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Sample records for reproductive allocation growth

  1. Mortality affects adaptive allocation to growth and reproduction: field evidence from a guild of body snatchers

    PubMed Central

    2010-01-01

    Background The probability of being killed by external factors (extrinsic mortality) should influence how individuals allocate limited resources to the competing processes of growth and reproduction. Increased extrinsic mortality should select for decreased allocation to growth and for increased reproductive effort. This study presents perhaps the first clear cross-species test of this hypothesis, capitalizing on the unique properties offered by a diverse guild of parasitic castrators (body snatchers). I quantify growth, reproductive effort, and expected extrinsic mortality for several species that, despite being different species, use the same species' phenotype for growth and survival. These are eight trematode parasitic castrators—the individuals of which infect and take over the bodies of the same host species—and their uninfected host, the California horn snail. Results As predicted, across species, growth decreased with increased extrinsic mortality, while reproductive effort increased with increased extrinsic mortality. The trematode parasitic castrator species (operating stolen host bodies) that were more likely to be killed by dominant species allocated less to growth and relatively more to current reproduction than did species with greater life expectancies. Both genders of uninfected snails fit into the patterns observed for the parasitic castrator species, allocating as much to growth and to current reproduction as expected given their probability of reproductive death (castration by trematode parasites). Additionally, species differences appeared to represent species-specific adaptations, not general plastic responses to local mortality risk. Conclusions Broadly, this research illustrates that parasitic castrator guilds can allow unique comparative tests discerning the forces promoting adaptive evolution. The specific findings of this study support the hypothesis that extrinsic mortality influences species differences in growth and reproduction

  2. Life history implications of allocation to growth versus reproduction in dynamic energy budgets.

    PubMed

    Lika, Konstadia; Kooijman, Sebastiaan A L M

    2003-09-01

    We compare the implications of determinate vs. indeterminate growth of a parthenogenetic iteroparous ectotherm at constant food density in the context of the dynamic energy budget theory, which specifies the tight links between life history traits, such as feeding, aging, growth and reproduction. We do a comparative analysis using, as measure of fitness, the life span reproduction, the population growth rate, and the conversion efficiency of food to biomass. When extrinsic mortality is constant, indeterminate growth cannot maximize fitness if measured by the population growth rate or the conversion efficiency, except when mortality is low, in which case both types of animals are similar. If the fitness measure is life span reproduction, indeterminate growth maximizes fitness even with constant mortality, provided it is not very high. When mortality decreases with size, indeterminate growth maximizes fitness for almost all measures of fitness. Finally, we suggest an evolutionary link between allocation strategies and expected life span. In populations of long living species, each type of animal can establish in the population of the other. In populations of short living species, determinate growers can invade, and displace, a population of indeterminate ones. However, when the mortality risk of organisms with small size is much higher than those of large size, indeterminate growers can be superior.

  3. Optimizing reproductive phenology in a two-resource world: a dynamic allocation model of plant growth predicts later reproduction in phosphorus-limited plants

    PubMed Central

    Nord, Eric A.; Shea, Katriona; Lynch, Jonathan P.

    2011-01-01

    Background and Aims Timing of reproduction is a key life-history trait that is regulated by resource availability. Delayed reproduction in soils with low phosphorus availability is common among annuals, in contrast to the accelerated reproduction typical of other low-nutrient environments. It is hypothesized that this anomalous response arises from the high marginal value of additional allocation to root growth caused by the low mobility of phosphorus in soils. Methods To better understand the benefits and costs of such delayed reproduction, a two-resource dynamic allocation model of plant growth and reproduction is presented. The model incorporates growth, respiration, and carbon and phosphorus acquisition of both root and shoot tissue, and considers the reallocation of resources from senescent leaves. The model is parameterized with data from Arabidopsis and the optimal reproductive phenology is explored in a range of environments. Key Results The model predicts delayed reproduction in low-phosphorus environments. Reproductive timing in low-phosphorus environments is quite sensitive to phosphorus mobility, but is less sensitive to the temporal distribution of mortality risks. In low-phosphorus environments, the relative metabolic cost of roots was greater, and reproductive allocation reduced, compared with high-phosphorus conditions. The model suggests that delayed reproduction in response to low phosphorus availability may be reduced in plants adapted to environments where phosphorus mobility is greater. Conclusions Delayed reproduction in low-phosphorus soils can be a beneficial response allowing for increased acquisition and utilization of phosphorus. This finding has implications both for efforts to breed crops for low-phosphorus soils, and for efforts to understand how climate change may impact plant growth and productivity in low-phosphorus environments. PMID:21712299

  4. Resource allocation to reproduction in animals.

    PubMed

    Kooijman, Sebastiaan A L M; Lika, Konstadia

    2014-11-01

    The standard Dynamic Energy Budget (DEB) model assumes that a fraction κ of mobilised reserve is allocated to somatic maintenance plus growth, while the rest is allocated to maturity maintenance plus maturation (in embryos and juveniles) or reproduction (in adults). All DEB parameters have been estimated for 276 animal species from most large phyla and all chordate classes. The goodness of fit is generally excellent. We compared the estimated values of κ with those that would maximise reproduction in fully grown adults with abundant food. Only 13% of these species show a reproduction rate close to the maximum possible (assuming that κ can be controlled), another 4% have κ lower than the optimal value, and 83% have κ higher than the optimal value. Strong empirical support hence exists for the conclusion that reproduction is generally not maximised. We also compared the parameters of the wild chicken with those of races selected for meat and egg production and found that the latter indeed maximise reproduction in terms of κ, while surface-specific assimilation was not affected by selection. We suggest that small values of κ relate to the down-regulation of maximum body size, and large values to the down-regulation of reproduction. We briefly discuss the ecological context for these findings.

  5. Quantifying and understanding reproductive allocation schedules in plants.

    PubMed

    Wenk, Elizabeth Hedi; Falster, Daniel S

    2015-12-01

    A plant's reproductive allocation (RA) schedule describes the fraction of surplus energy allocated to reproduction as it increases in size. While theorists use RA schedules as the connection between life history and energy allocation, little is known about RA schedules in real vegetation. Here we review what is known about RA schedules for perennial plants using studies either directly quantifying RA or that collected data from which the shape of an RA schedule can be inferred. We also briefly review theoretical models describing factors by which variation in RA may arise. We identified 34 studies from which aspects of an RA schedule could be inferred. Within those, RA schedules varied considerably across species: some species abruptly shift all resources from growth to reproduction; most others gradually shift resources into reproduction, but under a variety of graded schedules. Available data indicate the maximum fraction of energy allocated to production ranges from 0.1 to 1 and that shorter lived species tend to have higher initial RA and increase their RA more quickly than do longer-lived species. Overall, our findings indicate, little data exist about RA schedules in perennial plants. Available data suggest a wide range of schedules across species. Collection of more data on RA schedules would enable a tighter integration between observation and a variety of models predicting optimal energy allocation, plant growth rates, and biogeochemical cycles.

  6. Quantifying and understanding reproductive allocation schedules in plants.

    PubMed

    Wenk, Elizabeth Hedi; Falster, Daniel S

    2015-12-01

    A plant's reproductive allocation (RA) schedule describes the fraction of surplus energy allocated to reproduction as it increases in size. While theorists use RA schedules as the connection between life history and energy allocation, little is known about RA schedules in real vegetation. Here we review what is known about RA schedules for perennial plants using studies either directly quantifying RA or that collected data from which the shape of an RA schedule can be inferred. We also briefly review theoretical models describing factors by which variation in RA may arise. We identified 34 studies from which aspects of an RA schedule could be inferred. Within those, RA schedules varied considerably across species: some species abruptly shift all resources from growth to reproduction; most others gradually shift resources into reproduction, but under a variety of graded schedules. Available data indicate the maximum fraction of energy allocated to production ranges from 0.1 to 1 and that shorter lived species tend to have higher initial RA and increase their RA more quickly than do longer-lived species. Overall, our findings indicate, little data exist about RA schedules in perennial plants. Available data suggest a wide range of schedules across species. Collection of more data on RA schedules would enable a tighter integration between observation and a variety of models predicting optimal energy allocation, plant growth rates, and biogeochemical cycles. PMID:27069603

  7. Density-dependent reproductive and vegetative allocation in the aquatic plant Pistia stratiotes (Araceae).

    PubMed

    Coelho, Flávia Freitas; Deboni, Liene; Lopes, Frederico Santos

    2005-01-01

    Pistia stratiotes is an aquatic macrophyte that grows in temporary-ponds in the southern Pantanal, Brazil. It reproduces both sexually and asexually and is usually observed forming dense mats on the water surface, a condition favored by the plant's vegetative reproduction coupled with an ability for rapid growth. In this study we examined the effect of densely crowded conditions on the production of reproductive and vegetative structures. In addition, we verified whether there is a trade-off between clonal growth and investment in sexual reproductive structures, and whether there is an allocation pattern with plant size. Individual plant biomass and the number of the rosettes producing sexual reproductive structures and vegetative growth structures both increased with density. Increase in plant size resulted in increased proportional allocation to sexual reproductive structures and vegetative growth structures. Allocation of biomass to reproduction did not occur at the expense of clonal growth. Thus, the density response appears as a increase of rosettes producing sexual reproductive structures and vegetative growth structures. Therefore, long leaves and stolons may be adaptive under densely crowded conditions where competition for light is intense. An important aspect in the study of trade-offs is the size-dependency of the allocation patterns .Usually, larger plants produce more biomass. Therefore, larger plants can allocate more biomass to both vegetative and sexual reproduction than smaller plants and thus show a positive correlation between both traits rather than the expected negative one. PMID:17354448

  8. Reproductive success and failure: the role of winter body mass in reproductive allocation in Norwegian moose.

    PubMed

    Milner, Jos M; van Beest, Floris M; Solberg, Erling J; Storaas, Torstein

    2013-08-01

    A life history strategy that favours somatic growth over reproduction is well known for long-lived iteroparous species, especially in unpredictable environments. Risk-sensitive female reproductive allocation can be achieved by a reduced reproductive effort at conception, or the subsequent adjustment of investment during gestation or lactation in response to unexpected environmental conditions or resource availability. We investigated the relative importance of reduced investment at conception compared with later in the reproductive cycle (i.e. prenatal, perinatal or neonatal mortality) in explaining reproductive failure in two high-density moose (Alces alces) populations in southern Norway. We followed 65 multiparous, global positioning system (GPS)-collared females throughout the reproductive cycle and focused on the role of maternal nutrition during gestation in determining reproductive success using a quasi-experimental approach to manipulate winter forage availability. Pregnancy rates in early winter were normal (≥0.8) in all years while spring calving rates ranged from 0.4 to 0.83, with prenatal mortality accounting for most of the difference. Further losses over summer reduced autumn recruitment rates to 0.23-0.69, despite negligible predation. Over-winter mass loss explained variation in both spring calving and autumn recruitment success better than absolute body mass in early or late winter. Although pregnancy was related to body mass in early winter, overall reproductive success was unrelated to pre-winter body condition. We therefore concluded that reproductive success was limited by winter nutritional conditions. However, we could not determine whether the observed reproductive allocation adjustment was a bet-hedging strategy to maximise reproduction without compromising survival or whether females were simply unable to invest more resources in their offspring.

  9. Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive decisions.

    PubMed

    Johnson, Elizabeth L; Cunningham, Tyler W; Marriner, Sarah M; Kovacs, Jennifer L; Hunt, Brendan G; Bhakta, Dimpal B; Goodisman, Michael A D

    2009-07-01

    Organisms must make important decisions on how to allocate resources to reproduction. We investigated allocation decisions in the social wasp Vespula maculifrons to understand how social insects make reproductive choices. We first determined how annual colonies apportioned resources to growth and reproduction by analysing developing brood. In contrast to expectations, colonies invested in both growth (workers) and reproduction (males) simultaneously. In addition, colonies showed evidence of producing males in pulses and reversing their reproductive choices by decreasing investment in males late in the season. This reversal is consistent with theory suggesting that colonies decrease production in males if fitness of late emerging males is low. To further investigate reproductive decisions within colonies, we determined if the male mates of multiply-mated queens varied in their reproductive success over time. Sperm use by queens did vary over time suggesting that male success may depend on sperm clumping within the female reproductive tract. Finally, we tested if colony sex ratio conformed to expectations under kin selection theory that nestmate relatedness would positively correlate with investment in new queens if workers controlled sex allocation. Surprisingly, the proportion of queens produced by colonies was negatively correlated with nestmate relatedness, suggesting that allocation may be shaped by advantages arising from increased genetic diversity resulting from multiple mating by queens. Overall, our study suggests that the reproductive decisions of colonies are flexible and may depend both on environmental cues arising from energetic needs of the colony and genetic cues arising from mating behaviours of queens.

  10. Temporal Uncoupling between Energy Acquisition and Allocation to Reproduction in a Herbivorous-Detritivorous Fish

    PubMed Central

    Villamarín, Francisco; Magnusson, William E.; Jardine, Timothy D.; Valdez, Dominic; Woods, Ryan; Bunn, Stuart E.

    2016-01-01

    Although considerable knowledge has been gathered regarding the role of fish in cycling and translocation of nutrients across ecosystem boundaries, little information is available on how the energy obtained from different ecosystems is temporally allocated in fish bodies. Although in theory, limitations on energy budgets promote the existence of a trade-off between energy allocated to reproduction and somatic growth, this trade-off has rarely been found under natural conditions. Combining information on RNA:DNA ratios and carbon and nitrogen stable-isotope analyses we were able to achieve novel insights into the reproductive allocation of diamond mullet (Liza alata), a catadromous, widely distributed herbivorous-detritivorous fish. Although diamond mullet were in better condition during the wet season, most reproductive allocation occurred during the dry season when resources are limited and fish have poorer body condition. We found a strong trade-off between reproductive and somatic investment. Values of δ13C from reproductive and somatic tissues were correlated, probably because δ13C in food resources between dry and wet seasons do not differ markedly. On the other hand, data for δ15N showed that gonads are more correlated to muscle, a slow turnover tissue, suggesting long term synthesis of reproductive tissues. In combination, these lines of evidence suggest that L. alata is a capital breeder which shows temporal uncoupling of resource ingestion, energy storage and later allocation to reproduction. PMID:26938216

  11. Temporal Uncoupling between Energy Acquisition and Allocation to Reproduction in a Herbivorous-Detritivorous Fish.

    PubMed

    Villamarín, Francisco; Magnusson, William E; Jardine, Timothy D; Valdez, Dominic; Woods, Ryan; Bunn, Stuart E

    2016-01-01

    Although considerable knowledge has been gathered regarding the role of fish in cycling and translocation of nutrients across ecosystem boundaries, little information is available on how the energy obtained from different ecosystems is temporally allocated in fish bodies. Although in theory, limitations on energy budgets promote the existence of a trade-off between energy allocated to reproduction and somatic growth, this trade-off has rarely been found under natural conditions. Combining information on RNA:DNA ratios and carbon and nitrogen stable-isotope analyses we were able to achieve novel insights into the reproductive allocation of diamond mullet (Liza alata), a catadromous, widely distributed herbivorous-detritivorous fish. Although diamond mullet were in better condition during the wet season, most reproductive allocation occurred during the dry season when resources are limited and fish have poorer body condition. We found a strong trade-off between reproductive and somatic investment. Values of δ13C from reproductive and somatic tissues were correlated, probably because δ13C in food resources between dry and wet seasons do not differ markedly. On the other hand, data for δ15N showed that gonads are more correlated to muscle, a slow turnover tissue, suggesting long term synthesis of reproductive tissues. In combination, these lines of evidence suggest that L. alata is a capital breeder which shows temporal uncoupling of resource ingestion, energy storage and later allocation to reproduction. PMID:26938216

  12. Temporal Uncoupling between Energy Acquisition and Allocation to Reproduction in a Herbivorous-Detritivorous Fish.

    PubMed

    Villamarín, Francisco; Magnusson, William E; Jardine, Timothy D; Valdez, Dominic; Woods, Ryan; Bunn, Stuart E

    2016-01-01

    Although considerable knowledge has been gathered regarding the role of fish in cycling and translocation of nutrients across ecosystem boundaries, little information is available on how the energy obtained from different ecosystems is temporally allocated in fish bodies. Although in theory, limitations on energy budgets promote the existence of a trade-off between energy allocated to reproduction and somatic growth, this trade-off has rarely been found under natural conditions. Combining information on RNA:DNA ratios and carbon and nitrogen stable-isotope analyses we were able to achieve novel insights into the reproductive allocation of diamond mullet (Liza alata), a catadromous, widely distributed herbivorous-detritivorous fish. Although diamond mullet were in better condition during the wet season, most reproductive allocation occurred during the dry season when resources are limited and fish have poorer body condition. We found a strong trade-off between reproductive and somatic investment. Values of δ13C from reproductive and somatic tissues were correlated, probably because δ13C in food resources between dry and wet seasons do not differ markedly. On the other hand, data for δ15N showed that gonads are more correlated to muscle, a slow turnover tissue, suggesting long term synthesis of reproductive tissues. In combination, these lines of evidence suggest that L. alata is a capital breeder which shows temporal uncoupling of resource ingestion, energy storage and later allocation to reproduction.

  13. The effect of a rosette-crown fly, Botanophila turcica, on growth,biomass allocation and reproduction of the thistle Carthamus lanatus

    NASA Astrophysics Data System (ADS)

    Sheppard, Andrew W.; Vitou, Janine

    2000-12-01

    Plant growth and reproductive output of the winter annual invasive thistle, Carthamus lanatus was characterised in relation to plant size in three native populations in southern France. The effects of the rosette-crown feeding fly Botanophila turcica on these plant characteristics were assessed by comparing unattacked with naturally attacked plants at each site and by a field experiment. Indirect effects of B. turcica on plant seed production were also compared with direct seed loss caused by a guild of capitulum-feeding insects that incidentally attacked the marked plants at these sites. C. lanatus showed no size or weight requirement for flowering, but larger flowering plants produced less total receptacle surface and less seed production (female reproductive potential) in proportion to plant weight than smaller flowering plants. B. turcica did not select hosts on the basis of size or density. B. turcica reduced plant relative growth rate (RGR) in all situations, but attacked plants compensated fully at two of three sites as attack failed to halt rosette growth. Attacked plants suffered 12 % mortality, and 71 % lower seed production than unattacked plants at the site with the lowest RGR. This corresponded to 9 % lower seed production for the whole thistle population compared to 8.6-19.5 % direct seed loss to capitulum insects across all sites.

  14. Clonal Patch Size and Ramet Position of Leymus chinensis Affected Reproductive Allocation

    PubMed Central

    Zhang, Zhuo; Yang, Yunfei

    2015-01-01

    Reproductive allocation is critically important for population maintenance and usually varies with not only environmental factors but also biotic ones. As a typical rhizome clonal plant in China's northern grasslands, Leymus chinensis usually dominates the steppe communities and grows in clonal patches. In order to clarify the sexual reproductive allocation of L. chinensis in the process of the growth and expansion, we selected L. chinensis clonal patches of a range of sizes to examine the reproductive allocation and allometric growth of the plants. Moreover, the effects of position of L. chinensis ramets within the patch on their reproductive allocation were also examined. Clonal patch size and position both significantly affected spike biomass, reproductive tiller biomass and SPIKE/TILLER biomass ratio. From the central to the marginal zone, both the spike biomass and reproductive tiller biomass displayed an increasing trend in all the five patch size categories except for reproductive tiller biomass in 15–40m2 category. L. chinensis had significantly larger SPIKE/TILLER biomass ratio in marginal zone than in central zone of clonal patches that are larger than 15 m2 in area. Regression analysis showed that the spike biomass and SPIKE/TILLER biomass ratio were negatively correlated with clonal patch size while patch size showed significantly positive effect on SEED/SPIKE biomass ratio, but the reproductive tiller biomass and SEED/TILLER biomass ratio were not dependent on clonal patch size. The relationships between biomass of spike and reproductive tiller, between mature seed biomass and spike biomass and between mature seed biomass and reproductive tiller biomass were significant allometric for all or some of patch size categories, respectively. The slopes of all these allometric relationships were significantly different from 1. The allometric growth of L. chinensis is patch size-dependent. This finding will be helpful for developing appropriate practices for

  15. The dynamics of resource allocation and costs of reproduction in a sexually dimorphic, wind-pollinated dioecious plant.

    PubMed

    Teitel, Z; Pickup, M; Field, D L; Barrett, S C H

    2016-01-01

    Sexual dimorphism in resource allocation is expected to change during the life cycle of dioecious plants because of temporal differences between the sexes in reproductive investment. Given the potential for sex-specific differences in reproductive costs, resource availability may contribute to variation in reproductive allocation in females and males. Here, we used Rumex hastatulus, a dioecious, wind-pollinated annual plant, to investigate whether sexual dimorphism varies with life-history stage and nutrient availability, and determine whether allocation patterns differ depending on reproductive commitment. To examine if the costs of reproduction varied between the sexes, reproduction was either allowed or prevented through bud removal, and biomass allocation was measured at maturity. In a second experiment to assess variation in sexual dimorphism across the life cycle, and whether this varied with resource availability, plants were grown in high and low nutrients and allocation to roots, aboveground vegetative growth and reproduction were measured at three developmental stages. Males prevented from reproducing compensated with increased above- and belowground allocation to a much larger degree than females, suggesting that male reproductive costs reduce vegetative growth. The proportional allocation to roots, reproductive structures and aboveground vegetative growth varied between the sexes and among life-cycle stages, but not with nutrient treatment. Females allocated proportionally more resources to roots than males at peak flowering, but this pattern was reversed at reproductive maturity under low-nutrient conditions. Our study illustrates the importance of temporal dynamics in sex-specific resource allocation and provides support for high male reproductive costs in wind-pollinated plants.

  16. Reproductive efficiency and metabolism of female broiler breeders as affected by genotype, feed allocation, and age at photostimulation. 1. Pullet growth and development.

    PubMed

    Robinson, F E; Zuidhof, M J; Renema, R A

    2007-10-01

    A 3 x 4 x 2 factorial design was carried out to determine the effect of 3 broiler breeder strains, 4 target BW profiles, and 2 photostimulation ages on pullet growth and development. A total of 560 pullets from each strain (Hubbard Hi-Y, Ross 508, and Ross 708) were reared on BW profiles that separated at 4 wk and converged at 32 wk of age as follows: standard (mean target BW profile of the 3 strains used), low (12-wk BW target = 25% lower than standard followed by rapid gain to 32 wk), moderate (12-wk BW target = 150% of standard followed by lower rate of gain to 32 wk), and high (12-wk BW target = 200% of standard followed by minimal growth to 32 wk). Birds were photostimulated at 18 (18WK) or 22 wk (22WK). During the prephotostimulation phase (2 to 18 wk of age), 4 birds were killed for each of the 12 interactions at 14-d intervals to characterize changes in carcass traits. After 18 wk (wk 20, 22, and 24), 4 birds from each of the 24 interactions were killed and dissected (n = 768). Growth rate restricted frame size (e.g., 18-wk shank length: low = 101.8; standard = 105.6; moderate = 109.5; and high = 112.3 mm). At 24 wk of age, the 22WK birds had similar amounts of breast muscle compared with 18WK birds, whereas the later photostimulated hens had heavier abdominal fat pads. Early photo-stimulation resulted in increased 24-wk liver weights in all strains, but the difference was greatest in Ross 708 birds. The 22-wk ovary weight was influenced by age at photostimulation in high (18WK = 17.3; 22WK = 1.6 g) and moderate (18WK = 14.1; 22WK = 1.1 g) birds. The more extensive feed restriction of LOW birds before 12 wk of age appeared to limit breast muscle and fat pad growth and slow reproductive tract development following photostimulation. Pullets on heavier BW profiles respond to early PS by developing the reproductive system at the expense of breast muscle and fat pad growth. Genetic strain modulates some of the effect of very different target BW profiles.

  17. Plant reproductive allocation predicts herbivore dynamics across spatial and temporal scales.

    PubMed

    Miller, Tom E X; Tyre, Andrew J; Louda, Svata M

    2006-11-01

    Life-history theory suggests that iteroparous plants should be flexible in their allocation of resources toward growth and reproduction. Such plasticity could have consequences for herbivores that prefer or specialize on vegetative versus reproductive structures. To test this prediction, we studied the response of the cactus bug (Narnia pallidicornis) to meristem allocation by tree cholla cactus (Opuntia imbricata). We evaluated the explanatory power of demographic models that incorporated variation in cactus relative reproductive effort (RRE; the proportion of meristems allocated toward reproduction). Field data provided strong support for a single model that defined herbivore fecundity as a time-varying, increasing function of host RRE. High-RRE plants were predicted to support larger insect populations, and this effect was strongest late in the season. Independent field data provided strong support for these qualitative predictions and suggested that plant allocation effects extend across temporal and spatial scales. Specifically, late-season insect abundance was positively associated with interannual changes in cactus RRE over 3 years. Spatial variation in insect abundance was correlated with variation in RRE among five cactus populations across New Mexico. We conclude that plant allocation can be a critical component of resource quality for insect herbivores and, thus, an important mechanism underlying variation in herbivore abundance across time and space.

  18. Roots, shoots and reproduction: sexual dimorphism in size and costs of reproductive allocation in an annual herb.

    PubMed

    Harris, Mark S; Pannell, John R

    2008-11-22

    Females tend to be smaller than males in woody dioecious plant species, but they tend to be larger in herbs. The smaller size of females in woody species has been attributed to higher reproductive costs, yet no satisfactory explanation has been provided for their larger size in herbs. Because herbs have higher nitrogen concentrations in their tissues than woody plants, and because pollen is particularly rich in nitrogen, we predicted that male growth would be more compromised by reproduction than female growth. To test this hypothesis, we conducted three experiments on the annual dioecious herb Mercurialis annua. First, we compared the timing of reproduction between males and females and found that males started flowering earlier than females; early flowering is expected to compromise growth more than later flowering. Second, we compared plants allowed to flower with those prevented from flowering by experimental debudding and found that males incurred a higher reproductive cost than females in terms of both biomass and, particularly, nitrogen. Third, we grew plants under varying levels of nitrogen availability and found that although sexual size dimorphism was unaffected by nitrogen, females, but not males, decreased their relative allocation to both roots and reproduction under high nitrogen availability. We propose that males deal with the high cost of pollen production in terms of nitrogen by allocating biomass to nitrogen-harvesting roots, whereas females pay for carbon-rich seeds and fruits by investing in photosynthetic organs. Sexual dimorphism would thus seem to be the outcome of allocation to above- versus below-ground sinks that supply resources (carbon versus nitrogen) limiting the female and male reproduction differentially.

  19. Energy allocation and reproductive investment in a temperate protogynous hermaphrodite, the ballan wrasse Labrus bergylta

    NASA Astrophysics Data System (ADS)

    Villegas-Ríos, David; Alonso-Fernández, Alexandre; Domínguez-Petit, Rosario; Saborido-Rey, Fran

    2014-02-01

    Energy allocation is an important component of life-history variation since it determines the tradeoff between growth and reproduction. In this study we investigated the state-dependent and sex-specific energy allocation pattern and the reproductive investment of a protogynous hermaphrodite fish with parental care. Individuals of Labrus bergylta, a temperate wrasse displaying two main different colour patterns (plain and spotted), were obtained from the fish markets in NW Spain between 2009 and 2012. Total energy of the gonad, liver, mesenteric fat and muscle (obtained by calorimetric analysis) and gut weight (as a proxy of feeding intensity) were modelled in relation to the reproductive phase of the individuals. A decrease in the energy stored as mesenteric fat from prespawning to spawning paralleled the increase in the gonad total energy in the same period. The predicted reduction in stored total energy over the reproductive cycle was higher than the energy required to develop the ovaries for the full range of female sizes analysed, suggesting a capital breeding strategy. Males stored less energy over a season and invested fewer resources in gamete production than females. Reproductive investment (both fecundity and energy required to produce the gonads) was higher in plain than in spotted females, which is in agreement with the different growth patterns described for the species.

  20. To grow or to seed: ecotypic variation in reproductive allocation and cone production by young female Aleppo pine (Pinus halepensis, Pinaceae).

    PubMed

    Climent, José; Prada, M Aránzazu; Calama, Rafael; Chambel, M Regina; de Ron, David Sánchez; Alía, Ricardo

    2008-07-01

    Age and size at the first reproduction and the reproductive allocation of plants are linked to different life history strategies. Aleppo pine only reproduces through seed, and, as such, early female reproduction confers high fitness in its infertile highly fire-prone habitats along the Mediterranean coast because life expectancy is short. We investigated the extent of ecotypic differentiation in female reproductive allocation and examined the relation between early female reproduction and vegetative growth. In a common-garden experiment, the threshold age and size at first female reproduction and female reproductive allocation at age seven differed significantly among Aleppo pine provenances of ecologically distinct origin. Significant correlations among reproductive features of the provenances and the ecological traits of origin were found using different analytical tools. In nonlinear models of cone counts vs. stem volume, medium-sized trees (not the largest trees) produced the highest cone yield, confirming that, at the individual level, early female reproduction is incompatible with fast vegetative growth. The contribution of founder effects and adaptation to contrasting fire regimes may be confounding factors. But considering all traits analyzed, the geographical patterns of resource allocation by Aleppo pine suggest ecotypic specialization for either resource-poor (favoring early reproduction) or resource-rich (favoring vegetative growth) habitats.

  1. The impact of diet switching on resource allocation to reproduction and longevity in Mediterranean fruitflies.

    PubMed Central

    Romanyukha, A. A.; Carey, J. R.; Karkach, A. S.; Yashin, A. I.

    2004-01-01

    Understanding the factors that determine the allocation and utilization of organism resources may provide an insight into the mechanisms of adaptation, ageing and reproduction. Resource allocation, which is regarded as a method of adaptation, increases fitness and is genetically controlled. Experiments with variable diet feeding of female Mediterranean fruitflies (Ceratitis capitata) demonstrated that the feeding regime dramatically influences lifespan, mortality and the reproduction of flies. An analysis of experimental data and numerical experiments reveals that resource allocation could explain lifespan increase when females are switched from a sugar-only to a protein-containing diet. The heterogeneity of the initial female cohort in terms of the total amount of resources and its allocation to the processes of maintenance and reproduction plays a significant role in this. PMID:15306357

  2. Differential allocation of protein resources to flight muscles and reproductive organs in the flightless wing-polymorphic bug, Pyrrhocoris apterus (L.) (Heteroptera).

    PubMed

    Socha, R; Sula, J

    2008-02-01

    Differences in the growth of dorsolongitudinal flight muscles and gonads in 1-28 days old long-winged (macropterous) and short-winged (brachypterous) adults of the firebug (Pyrrhocoris apterus L.) and the resource allocation to these organs were studied by means of total protein analysis. We found predominant allocation of food resources to flight muscles compared to reproductive organs in both macropterous males and females during the first 5 days of adult life. Subsequent histolysis of developed flight muscles coincided with increased total protein content in some reproductive organs. Initiation of intensive food intake after starvation or application of higher dose of methoprene on macropterous adults changed the resource allocation in favour of growth of reproductive organs and induced precocious histolysis of flight muscles. It indicates an involvement of juvenile hormone in wing morph-related differential allocation of resources in the bug. Increased total protein contents in the ovaries and accessory glands of starved macropterous females and males treated with methoprene, respectively, indicate that proteins derived from the methoprene-induced histolysis of the flight muscles are re-utilized for the growth of the reproductive organs. It is the first report of persistence of differential resource allocation to flight muscles and reproductive organs in the wing-polymorphic insects with non-functional macropterism.

  3. Effects of aspect on clonal reproduction and biomass allocation of layering modules of Nitraria tangutorum in nebkha dunes.

    PubMed

    Li, Qinghe; Xu, Jun; Li, Huiqing; Wang, Saixiao; Yan, Xiu; Xin, Zhiming; Jiang, Zeping; Wang, Linlong; Jia, Zhiqing

    2013-01-01

    The formation of many nebkha dunes relies on the layering of clonal plants. The microenvironmental conditions of such phytogenic nebkha are heterogeneous depending on the aspect and slope. Exploring the effects of aspect on clonal reproduction and biomass allocation can be useful in understanding the ecological adaptation of species. We hypothesized that on the windward side layering propagation would be promoted, that biomass allocation to leaves and stems of ramets would increase, and that the effects of aspect would be greater in the layering with larger biomass. To test these hypotheses, we surveyed the depth of germination points of axillary buds, the rate of ramet sprouting, the density of adventitious root formation points, and the biomass of modules sprouting from layering located on the NE, SE, SW and NW, aspects of Nitraria tangutorum nebkhas. The windward side was located on the NW and SW aspects. The results indicated that conditions of the NW aspect were more conducive to clonal reproduction and had the highest rate of ramet sprouting and the highest density of adventitious formation points. For the modules sprouting from layering on the SW aspect, biomass allocation to leaves and stems was greatest with biomass allocation to adventitious roots being lowest. This result supported our hypothesis. Contrary to our hypothesis, the effects of aspect were greater in layering of smaller biomass. These results support the hypothesis that aspect does affect layering propagation capacity and biomass allocation in this species. Additionally, clonal reproduction and biomass allocation of modules sprouting from layering with smaller biomass was more affected by aspect. These results suggest that the clonal growth of N. tangutorum responses to the microenvironmental heterogeneity that results from aspect of the nebkha.

  4. Effects of Aspect on Clonal Reproduction and Biomass Allocation of Layering Modules of Nitraria tangutorum in Nebkha Dunes

    PubMed Central

    Li, Qinghe; Xu, Jun; Li, Huiqing; Wang, Saixiao; Yan, Xiu; Xin, Zhiming; Jiang, Zeping; Wang, Linlong; Jia, Zhiqing

    2013-01-01

    The formation of many nebkha dunes relies on the layering of clonal plants. The microenvironmental conditions of such phytogenic nebkha are heterogeneous depending on the aspect and slope. Exploring the effects of aspect on clonal reproduction and biomass allocation can be useful in understanding the ecological adaptation of species. We hypothesized that on the windward side layering propagation would be promoted, that biomass allocation to leaves and stems of ramets would increase, and that the effects of aspect would be greater in the layering with larger biomass. To test these hypotheses, we surveyed the depth of germination points of axillary buds, the rate of ramet sprouting, the density of adventitious root formation points, and the biomass of modules sprouting from layering located on the NE, SE, SW and NW, aspects of Nitraria tangutorum nebkhas. The windward side was located on the NW and SW aspects. The results indicated that conditions of the NW aspect were more conducive to clonal reproduction and had the highest rate of ramet sprouting and the highest density of adventitious formation points. For the modules sprouting from layering on the SW aspect, biomass allocation to leaves and stems was greatest with biomass allocation to adventitious roots being lowest. This result supported our hypothesis. Contrary to our hypothesis, the effects of aspect were greater in layering of smaller biomass. These results support the hypothesis that aspect does affect layering propagation capacity and biomass allocation in this species. Additionally, clonal reproduction and biomass allocation of modules sprouting from layering with smaller biomass was more affected by aspect. These results suggest that the clonal growth of N. tangutorum responses to the microenvironmental heterogeneity that results from aspect of the nebkha. PMID:24205391

  5. FT Duplication Coordinates Reproductive and Vegetative Growth

    SciTech Connect

    Hsu, Chuan-Yu; Adams, Joshua P.; Kim, Hyejin; No, Kyoungok; Ma, Caiping; Strauss, Steven; Drnevich, Jenny; Wickett, Norman; Vandervelde, Lindsay; Ellis, Jeffrey D.; Rice, Brandon; Gunter, Lee E; Tuskan, Gerald A; Brunner, Amy M.; Page, Grier P.; Carlson, John E.; DePamphilis, Claude; Luthe, Dawn S.; Yuceer, Cetin

    2011-01-01

    Annual plants grow vegetatively at early developmental stages and then transition to the reproductive stage, followed by senescence in the same year. In contrast, after successive years of vegetative growth at early ages, woody perennial shoot meristems begin repeated transitions between vegetative and reproductive growth at sexual maturity. However, it is unknown how these repeated transitions occur without a developmental conflict between vegetative and reproductive growth. We report that functionally diverged paralogs FLOWERING LOCUS T1 (FT1) and FLOWERING LOCUS T2 (FT2), products of whole-genome duplication and homologs of Arabidopsis thaliana gene FLOWERING LOCUS T (FT), coordinate the repeated cycles of vegetative and reproductive growth in woody perennial poplar (Populus spp.). Our manipulative physiological and genetic experiments coupled with field studies, expression profiling, and network analysis reveal that reproductive onset is determined by FT1 in response to winter temperatures, whereas vegetative growth and inhibition of bud set are promoted by FT2 in response to warm temperatures and long days in the growing season. The basis for functional differentiation between FT1 and FT2 appears to be expression pattern shifts, changes in proteins, and divergence in gene regulatory networks. Thus, temporal separation of reproductive onset and vegetative growth into different seasons via FT1 and FT2 provides seasonality and demonstrates the evolution of a complex perennial adaptive trait after genome duplication.

  6. Individual heterogeneity and offspring sex affect the growth-reproduction trade-off in a mammal with indeterminate growth.

    PubMed

    Gélin, Uriel; Wilson, Michelle E; Cripps, Jemma; Coulson, Graeme; Festa-Bianchet, Marco

    2016-04-01

    Reproduction can lead to a trade-off with growth, particularly when individuals reproduce before completing body growth. Kangaroos have indeterminate growth and may always face this trade-off. We combined an experimental manipulation of reproductive effort and multi-year monitoring of a large sample size of marked individuals in two populations of eastern grey kangaroos to test the predictions (1) that reproduction decreases skeletal growth and mass gain and (2) that mass loss leads to reproductive failure. We also tested if sex-allocation strategies influenced these trade-offs. Experimental reproductive suppression revealed negative effects of reproduction on mass gain and leg growth from 1 year to the next. Unmanipulated females, however, showed a positive correlation between number of days lactating and leg growth over periods of 2 years and longer, suggesting that over the long term, reproductive costs were masked by individual heterogeneity in resource acquisition. Mass gain was necessary for reproductive success the subsequent year. Although mothers of daughters generally lost more mass than females nursing sons, mothers in poor condition experienced greater mass gain and arm growth if they had daughters than if they had sons. The strong links between individual mass changes and reproduction suggest that reproductive tactics are strongly resource-dependent.

  7. Reproductive Allocation of Biomass and Nitrogen in Annual and Perennial Lesquerella Crops

    PubMed Central

    PLOSCHUK, E. L.; SLAFER, G. A.; RAVETTA, D. A.

    2005-01-01

    • Background and Aims The use of perennial crops could contribute to increase agricultural sustainability. However, almost all of the major grain crops are herbaceous annuals and opportunities to replace them with more long-lived perennials have been poorly explored. This follows the presumption that the perennial life cycle is associated with a lower potential yield, due to a reduced allocation of biomass to grains. The hypothesis was tested that allocation to perpetuation organs in the perennial L. mendocina would not be directly related to a lower allocation to seeds. • Methods Two field experiments were carried on with the annual Lesquerella fendleri and the iteroparous perennial L. mendocina, two promising oil-seed crops for low-productivity environments, subjected to different water and nitrogen availability. • Key Results Seed biomass allocation was similar for both species, and unresponsive to water and nitrogen availability. Greater root and vegetative shoot allocation in the perennial was counterbalanced by a lower allocation to other reproductive structures compared with the annual Lesquerella. Allometric relationships revealed that allocation differences between the annual and the perennial increased linearly with plant size. The general allocation patterns for nitrogen did not differ from those of biomass. However, nitrogen concentrations were higher in the vegetative shoot and root of L. mendocina than of L. fendleri but remained stable in seeds of both species. • Conclusions It is concluded that vegetative organs are more hierarchically important sinks in L. mendocina than in the annual L. fendleri, but without disadvantages in seed hierarchy. PMID:15863469

  8. Plasticity in reproduction and growth among 52 range-wide populations of a Mediterranean conifer: adaptive responses to environmental stress.

    PubMed

    Santos-Del-Blanco, L; Bonser, S P; Valladares, F; Chambel, M R; Climent, J

    2013-09-01

    A plastic response towards enhanced reproduction is expected in stressful environments, but it is assumed to trade off against vegetative growth and efficiency in the use of available resources deployed in reproduction [reproductive efficiency (RE)]. Evidence supporting this expectation is scarce for plants, particularly for long-lived species. Forest trees such as Mediterranean pines provide ideal models to study the adaptive value of allocation to reproduction vs. vegetative growth given their among-population differentiation for adaptive traits and their remarkable capacity to cope with dry and low-fertility environments. We studied 52 range-wide Pinus halepensis populations planted into two environmentally contrasting sites during their initial reproductive stage. We investigated the effect of site, population and their interaction on vegetative growth, threshold size for female reproduction, reproductive-vegetative size relationships and RE. We quantified correlations among traits and environmental variables to identify allocation trade-offs and ecotypic trends. Genetic variation for plasticity was high for vegetative growth, whereas it was nonsignificant for reproduction. Size-corrected reproduction was enhanced in the more stressful site supporting the expectation for adverse conditions to elicit plastic responses in reproductive allometry. However, RE was unrelated with early reproductive investment. Our results followed theoretical predictions and support that phenotypic plasticity for reproduction is adaptive under stressful environments. Considering expectations of increased drought in the Mediterranean, we hypothesize that phenotypic plasticity together with natural selection on reproductive traits will play a relevant role in the future adaptation of forest tree species.

  9. Relationship between Reproductive Allocation and Relative Abundance among 32 Species of a Tibetan Alpine Meadow: Effects of Fertilization and Grazing

    PubMed Central

    Niu, Kechang; Schmid, Bernhard; Choler, Philippe; Du, Guozhen

    2012-01-01

    Background Understanding the relationship between species traits and species abundance is an important goal in ecology and biodiversity science. Although theoretical studies predict that traits related to performance (e.g. reproductive allocation) are most directly linked to species abundance within a community, empirical investigations have rarely been done. It also remains unclear how environmental factors such as grazing or fertilizer application affect the predicted relationship. Methodology We conducted a 3-year field experiment in a Tibetan alpine meadow to assess the relationship between plant reproductive allocation (RA) and species relative abundance (SRA) on control, grazed and fertilized plots. Overall, the studied plant community contained 32 common species. Principal Findings At the treatment level, (i) RA was negatively correlated with SRA on control plots and during the first year on fertilized plots. (ii) No negative RA–SRA correlations were observed on grazed plots and during the second and third year on fertilized plots. (iii) Seed size was positively correlated with SRA on control plots. At the plot level, the correlation between SRA and RA were not affected by treatment, year or species composition. Conclusions/Significance Our study shows that the performance-related trait RA can negatively affect SRA within communities, which is possibly due to the tradeoffs between clonal growth (for space occupancy) and sexual reproduction. We propose that if different species occupy different positions along these tradeoffs it will contribute to biodiversity maintenance in local communities or even at lager scale. PMID:22536385

  10. Effects of Tidal Action on Pollination and Reproductive Allocation in an Estuarine Emergent Wetland Plant–Sagittaria graminea (Alismataceae)

    PubMed Central

    Zhang, Yanwen; Zhang, Lihui; Zhao, Xingnan; Huang, Shengjun; Zhao, Jimin

    2013-01-01

    In estuarine wetlands, the daily periodic tidal activity has a profound effect on plant growth and reproduction. We studied the effects of tidal action on pollination and reproductive allocation of Sagittaria graminea. Results showed that the species had very different reproductive allocation in tidal and non-tidal habitats. In the tidal area, seed production was only 9.7% of that in non-tidal habitat, however, plants produced more male flowers and nearly twice the corms compared to those in non-tidal habitat. An experiment showed that the time available for effective pollination determined the pollination rate and pollen deposition in the tidal area. A control experiment suggested that low pollen deposition from low visitation frequency is not the main cause of very low seed sets or seed production in this plant in tidal habitat. The negative effects of tides (water) on pollen germination may surpass the influence of low pollen deposition from low visitation frequency. The length of time from pollen deposition to flower being submerged by water affected pollen germination rate on stigmas; more than three hours is necessary to allow pollen germination and complete fertilization to eliminate the risk of pollen grains being washed away by tidal water. PMID:24244393

  11. Symbiotic regulation of plant growth, development and reproduction

    USGS Publications Warehouse

    Rodriguez, R.J.; Freeman, D. Carl; McArthur, E.D.; Kim, Y.-O.; Redman, R.S.

    2009-01-01

    The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte colonized (symbiotic) plants preferentially allocated resources into root growth until root hairs were well established. During that time symbiotic roots expanded at five times the rate observed in nonsymbiotic plants. Endophytes also influenced sexual reproduction of mature big sagebrush (Artemisia tridentata) plants. Two spatially distinct big sagebrush subspecies and their hybrids were symbiotic with unique fungal endophytes, despite being separated by only 380 m distance and 60 m elevation. A double reciprocal transplant experiment of parental and hybrid plants, and soils across the hybrid zone showed that fungal endophytes interact with the soils and different plant genotypes to confer enhanced plant reproduction in soil native to the endophyte and reduced reproduction in soil alien to the endophyte. Moreover, the most prevalent endophyte of the hybrid zone reduced the fitness of both parental subspecies. Because these endophytes are passed to the next generation of plants on seed coats, this interaction provides a selective advantage, habitat specificity, and the means of restricting gene flow, thereby making the hybrid zone stable, narrow and potentially leading to speciation. ?? 2009 Landes Bioscience.

  12. Alternative reproductive tactics in snail shell-brooding cichlids diverge in energy reserve allocation.

    PubMed

    von Kuerthy, Corinna; Tschirren, Linda; Taborsky, Michael

    2015-05-01

    Life history theory predicts that the amount of resources allocated to reproduction should maximize an individual's lifetime reproductive success. So far, resource allocation in reproduction has been studied mainly in females. Intraspecific variation of endogenous energy storage and utilization patterns of males has received little attention, although these patterns may vary greatly between individuals pursuing alternative reproductive tactics (ARTs). ARTs are characterized by systematic variation of behavioral, physiological, and often morphological traits among same-sex conspecifics. Some individuals may rely on previously accumulated reserves, because of limited foraging opportunities during reproduction. Others may be able to continue foraging during reproduction, thus relying on reserves to a lesser extent. We therefore predicted that, if male tactics involve such divergent limitations and trade-offs within a species, ARTs should correspondingly differ in energy reserve allocation and utilization. To test this prediction, we studied short-term and long-term reserve storage patterns of males in the shell-brooding cichlid Lamprologus callipterus. In this species, bourgeois males investing in territory defense, courtship, and guarding of broods coexist with two distinct parasitic male tactics: (1) opportunistic sneaker males attempting to fertilize eggs by releasing sperm into the shell opening when a female is spawning; and (2) specialized dwarf males attempting to enter the shell past the spawning female to fertilize eggs from inside the shell. Sneaker males differed from other male types by showing the highest amount of accumulated short-term and long-term fat stores, apparently anticipating their upcoming adoption of the nest male status. In contrast, nest males depleted previously accumulated energy reserves with increasing nest holding period, as they invest heavily into costly reproductive behaviors while not taking up any food. This conforms to a capital

  13. Alternative reproductive tactics in snail shell-brooding cichlids diverge in energy reserve allocation

    PubMed Central

    von Kuerthy, Corinna; Tschirren, Linda; Taborsky, Michael

    2015-01-01

    Life history theory predicts that the amount of resources allocated to reproduction should maximize an individual's lifetime reproductive success. So far, resource allocation in reproduction has been studied mainly in females. Intraspecific variation of endogenous energy storage and utilization patterns of males has received little attention, although these patterns may vary greatly between individuals pursuing alternative reproductive tactics (ARTs). ARTs are characterized by systematic variation of behavioral, physiological, and often morphological traits among same-sex conspecifics. Some individuals may rely on previously accumulated reserves, because of limited foraging opportunities during reproduction. Others may be able to continue foraging during reproduction, thus relying on reserves to a lesser extent. We therefore predicted that, if male tactics involve such divergent limitations and trade-offs within a species, ARTs should correspondingly differ in energy reserve allocation and utilization. To test this prediction, we studied short-term and long-term reserve storage patterns of males in the shell-brooding cichlid Lamprologus callipterus. In this species, bourgeois males investing in territory defense, courtship, and guarding of broods coexist with two distinct parasitic male tactics: (1) opportunistic sneaker males attempting to fertilize eggs by releasing sperm into the shell opening when a female is spawning; and (2) specialized dwarf males attempting to enter the shell past the spawning female to fertilize eggs from inside the shell. Sneaker males differed from other male types by showing the highest amount of accumulated short-term and long-term fat stores, apparently anticipating their upcoming adoption of the nest male status. In contrast, nest males depleted previously accumulated energy reserves with increasing nest holding period, as they invest heavily into costly reproductive behaviors while not taking up any food. This conforms to a capital

  14. Allometry of within-fruit reproductive allocation in subtropical dicot woody species.

    PubMed

    Chen, Hong; Felker, Sara; Sun, Shucun

    2010-04-01

    Angiosperm fruits typically consist of pericarp and seed, which collectively function to maximize plant reproductive success. Within-fruit reproductive allocation has been scarcely examined across a wide range of fruit types and taxa although it is critical to the understanding of the evolution of fruit size and seed size. We investigated seed size, fruit size, seed number per fruit (SNF), and within-fruit biomass allocation between seed mass and pericarp mass for 62 dicot woody species (27 deciduous and 35 evergreen species) of a subtropical evergreen forest in southwest China. At the fruit level, total pericarp mass (TPM) isometrically scaled with increasing total seed mass (TSM) in the evergreen species and in the pooled data set, while TPM increased faster than TSM in the deciduous species. The slope difference is possibly due to the difference in the timing of fruit development between the two species groups. At the seed level, seed package (pericarp mass per seed) isometrically scaled with increasing seed size in the deciduous group, but less than isometrically in the evergreens and in the pooled data set. SNF was negatively correlated with seed size but positively correlated with the proportion of pericarp within fruits. In conclusion, within-fruit biomass allocation is significantly affected by seed size, fruit size, and SNF in both deciduous and evergreen species. The implications of the observed scaling relationships are discussed in relation to seed size evolution and global patterns of seed size variation.

  15. Photosynthate allocations patterns and mode of postfire reproduction in two shrub species from the California chaparral

    SciTech Connect

    Sparks, S.R.

    1989-01-01

    Age-specific patterns of photosynthate allocation in leaves were investigated for two chaparral shrubs, Adenostoma fasciculatum and Ceanothus greggii, in five stands of various ages. Branches of shrubs were labeled with {sup 14}CO{sub 2}, and seasonal allocation of {sup 14}C-labeled photosynthate to storage, defense, metabolic, and structural compounds was followed. Age-specific allocation patterns were found only in the spring, when older shrubs showed a reduced allocation of photosynthate within leaves to storage compounds. Older shrubs may be less able than younger shrubs to allocate photosynthate to storage compounds when demands on photosynthate for growth are high. The influence of senescence on postfire sprouting was investigated by quantifying the proportion of standing dead biomass in A. fasciculatum, as well as other shrub structural characteristics, before an experimental burn. After the burn, sprout production during the first postfire season was determined and correlated with prefire structural characteristics. Photosynthate allocation to shoots and roots was investigated for seedlings of both species.

  16. Metabolic stressors and signals differentially affect energy allocation between reproduction and immune function.

    PubMed

    Carlton, Elizabeth D; Cooper, Candace L; Demas, Gregory E

    2014-11-01

    Most free-living animals have finite energy stores that they must allocate to different physiological and behavioral processes. In times of energetic stress, trade-offs in energy allocation among these processes may occur. The manifestation of trade-offs may depend on the source (e.g., glucose, lipids) and severity of energy limitation. In this study, we investigated energetic trade-offs between the reproductive and immune systems by experimentally limiting energy availability to female Siberian hamsters (Phodopus sungorus) with 2-deoxy-d-glucose, a compound that disrupts cellular utilization of glucose. We observed how glucoprivation at two levels of severity affected allocation to reproduction and immunity. Additionally, we treated a subset of these hamsters with leptin, an adipose hormone that provides a direct signal of available fat stores, in order to determine how increasing this signal of fat stores influences glucoprivation-induced trade-offs. We observed trade-offs between the reproductive and immune systems and that these trade-offs depended on the severity of energy limitation and exogenous leptin signaling. The majority of the animals experiencing mild glucoprivation entered anestrus, whereas leptin treatment restored estrous cycling in these animals. Surprisingly, virtually all animals experiencing more severe glucoprivation maintained normal estrous cycling throughout the experiment; however, exogenous leptin resulted in lower antibody production in this group. These data suggest that variation in these trade-offs may be mediated by shifts between glucose and fatty acid utilization. Collectively, the results of the present study highlight the context-dependent nature of these trade-offs, as trade-offs induced by the same metabolic stressor can manifest differently depending on its intensity.

  17. Hierarchical reproductive allocation and allometry within a perennial bunchgrass after 11 years of nutrient addition.

    PubMed

    Tian, Dashuan; Pan, Qingmin; Simmons, Matthew; Chaolu, Hada; Du, Baohong; Bai, Yongfei; Wang, Hong; Han, Xingguo

    2012-01-01

    Bunchgrasses are one of the most important plant functional groups in grassland ecosystems. Reproductive allocation (RA) for a bunchgrass is a hierarchical process; however, how bunchgrasses adjust their RAs along hierarchical levels in response to nutrient addition has never been addressed. Here, utilizing an 11-year nutrient addition experiment, we examined the patterns and variations in RA of Agropyron cristatum at the individual, tiller and spike levels. We evaluated the reproductive allometric relationship at each level by type II regression analysis to determine size-dependent and size-independent effects on plant RA variations. Our results indicate that the proportion of reproductive individuals in A. cristatum increased significantly after 11 years of nutrient addition. Adjustments in RA in A. cristatum were mainly occurred at the individual and tiller levels but not at the spike level. A size-dependent effect was a dominant mechanism underlying the changes in plant RA at both individual and tiller levels. Likewise, the distribution of plant size was markedly changed with large individuals increasing after nutrient addition. Tiller-level RA may be a limiting factor for the adjustment of RA in A. cristatum. To the best of our knowledge, this study is the first to examine plant responses in terms of reproductive allocation and allometry to nutrient enrichment within a bunchgrass population from a hierarchical view. Our findings have important implications for understanding the mechanisms underlying bunchgrass responses in RA to future eutrophication due to human activities. In addition, we developed a hierarchical analysis method for disentangling the mechanisms that lead to variation in RA for perennial bunchgrasses.

  18. Ant species identity mediates reproductive traits and allocation in an ant-garden bromeliad

    PubMed Central

    Leroy, Céline; Corbara, Bruno; Pélozuelo, Laurent; Carrias, Jean-François; Dejean, Alain; Céréghino, Régis

    2012-01-01

    Background and Aims Determining the sources of variation in floral morphology is crucial to understanding the mechanisms underlying Angiosperm evolution. The selection of floral and reproductive traits is influenced by the plant's abiotic environment, florivores and pollinators. However, evidence that variations in floral traits result from mutualistic interactions with insects other than pollinators is lacking in the published literature and has rarely been investigated. We aimed to determine whether the association with either Camponotus femoratus or Pachycondyla goeldii (both involved in seed dispersal and plant protection) mediates the reproductive traits and allocation of Aechmea mertensii, an obligatory ant-garden tank-bromeliad, differently. Methods Floral and reproductive traits were compared between the two A. mertensii ant-gardens. The nitrogen flux from the ants to the bromeliads was investigated through experimental enrichments with stable isotopes (15N). Key Results Camponotus femoratus-associated bromeliads produced inflorescences up to four times longer than did P. goeldii-associated bromeliads. Also, the numbers of flowers and fruits were close to four times higher, and the number of seeds and their mass per fruit were close to 1·5 times higher in C. femoratus than in P. goeldii-associated bromeliads. Furthermore, the 15N-enrichment experiment showed that C. femoratus-associated bromeliads received more nitrogen from ants than did P. goeldii-associated bromeliads, with subsequent positive repercussions on floral development. Greater benefits were conferred to A. mertensii by the association with C. femoratus compared with P. goeldii ants. Conclusions We show for the first time that mutualistic associations with ants can result in an enhanced reproductive allocation for the bromeliad A. mertensii. Nevertheless, the strength and direction of the selection of floral and fruit traits change based on the ant species and were not related to light

  19. Risk-sensitive reproductive allocation: fitness consequences of body mass losses in two contrasting environments

    PubMed Central

    Bårdsen, Bård-Jørgen; Næss, Marius Warg; Tveraa, Torkild; Langeland, Knut; Fauchald, Per

    2014-01-01

    For long-lived organisms, the fitness value of survival is greater than that of current reproduction. Asymmetric fitness rewards suggest that organisms inhabiting unpredictable environments should adopt a risk-sensitive life history, predicting that it is adaptive to allocate resources to increase their own body reserves at the expense of reproduction. We tested this using data from reindeer populations inhabiting contrasting environments and using winter body mass development as a proxy for the combined effect of winter severity and density dependence. Individuals in good and harsh environments responded similarly: Females who lost large amounts of winter body mass gained more body mass the coming summer compared with females losing less mass during winter. Additionally, females experienced a cost of reproduction: On average, barren females gained more body mass than lactating females. Winter body mass development positively affected both the females' reproductive success and offspring body mass. Finally, we discuss the relevance of our findings with respect to scenarios for future climate change. PMID:24772280

  20. [Effects of UV-B radiation on the growth and reproduction of Vicia angustifolia].

    PubMed

    Wang, Ying; Wang, Xing-An; Wang, Ren-Jun; Qiu, Nian-Wei; Ma, Zong-Qi; Du, Guo-Zhen

    2012-05-01

    A simulation experiment with supplementation and exclusion of solar ultraviolet-B (UV-B) radiation was conducted to study the effects of enhanced and near ambient UV-B radiation on the growth and reproduction of alpine annual pasture Vicia angustifolia on Qinghai-Tibet Plateau. Enhanced UV-B decreased the plant height and biomass, biomass allocation to fruit, flower number, and 100-seed mass significantly, delayed flowering stage, increased the concentration degree of flowering and success rate of reproduction, but had little effect on seed yield. Near ambient UV-B radiation made the plant height increased after an initial decrease, decreased biomass allocation to fruit and 100-seed mass, but little affected flowering duration, flower number, and seed yield. Both enhanced and near ambient UV-B radiation could inhibit the growth and production of V. angustifolia, and the effect of enhanced UV-B radiation was even larger.

  1. Renewable and nonrenewable resources: amino acid turnover and allocation to reproduction in Lepidoptera.

    PubMed

    O'Brien, Diane M; Fogel, Marilyn L; Boggs, Carol L

    2002-04-01

    The allocation of nutritional resources to reproduction in animals is a complex process of great evolutionary significance. We use compound-specific stable isotope analysis of carbon (GC/combustion/isotope ratio MS) to investigate the dietary sources of egg amino acids in a nectar-feeding hawkmoth. Previous work suggests that the nutrients used in egg manufacture fall into two classes: those that are increasingly synthesized from adult dietary sugar over a female's lifetime (renewable resources), and those that remain exclusively larval in origin (nonrenewable resources). We predict that nonessential and essential amino acids correspond to these nutrient classes and test this prediction by analyzing egg amino acids from females fed isotopically distinct diets as larvae and as adults. The results demonstrate that essential egg amino acids originate entirely from the larval diet. In contrast, nonessential egg amino acids were increasingly synthesized from adult dietary sugars, following a turnover pattern across a female's lifetime. This study demonstrates that female Lepidoptera can synthesize a large fraction of egg amino acids from nectar sugars, using endogenous sources of nitrogen. However, essential amino acids derive only from the larval diet, placing an upper limit on the use of adult dietary resources to enhance reproductive success.

  2. Renewable and nonrenewable resources: amino acid turnover and allocation to reproduction in Lepidoptera.

    PubMed

    O'Brien, Diane M; Fogel, Marilyn L; Boggs, Carol L

    2002-04-01

    The allocation of nutritional resources to reproduction in animals is a complex process of great evolutionary significance. We use compound-specific stable isotope analysis of carbon (GC/combustion/isotope ratio MS) to investigate the dietary sources of egg amino acids in a nectar-feeding hawkmoth. Previous work suggests that the nutrients used in egg manufacture fall into two classes: those that are increasingly synthesized from adult dietary sugar over a female's lifetime (renewable resources), and those that remain exclusively larval in origin (nonrenewable resources). We predict that nonessential and essential amino acids correspond to these nutrient classes and test this prediction by analyzing egg amino acids from females fed isotopically distinct diets as larvae and as adults. The results demonstrate that essential egg amino acids originate entirely from the larval diet. In contrast, nonessential egg amino acids were increasingly synthesized from adult dietary sugars, following a turnover pattern across a female's lifetime. This study demonstrates that female Lepidoptera can synthesize a large fraction of egg amino acids from nectar sugars, using endogenous sources of nitrogen. However, essential amino acids derive only from the larval diet, placing an upper limit on the use of adult dietary resources to enhance reproductive success. PMID:11930002

  3. Maternal nutrition affects reproductive output and sex allocation in a lizard with environmental sex determination

    PubMed Central

    Warner, Daniel A; Lovern, Matthew B; Shine, Richard

    2007-01-01

    Life-history traits such as offspring size, number and sex ratio are affected by maternal feeding rates in many kinds of animals, but the consequences of variation in maternal diet quality (rather than quantity) are poorly understood. We manipulated dietary quality of reproducing female lizards (Amphibolurus muricatus; Agamidae), a species with temperature-dependent sex determination, to examine strategies of reproductive allocation. Females maintained on a poor-quality diet produced fewer clutches but massively (twofold) larger eggs with lower concentrations of yolk testosterone than did conspecific females given a high-quality diet. Although all eggs were incubated at the same temperature, and yolk steroid hormone levels were not correlated with offspring sex, the nutrient-deprived females produced highly male-biased sex ratios among their offspring. These responses to maternal nutrition generate a link between sex and offspring size, in a direction likely to enhance maternal fitness if large body size enhances reproductive success more in sons than in daughters (as seems plausible, given the mating system of this species). Overall, our results show that sex determination in these animals is more complex, and responsive to a wider range of environmental cues, than that suggested by the classification of ‘environmental sex determination’. PMID:17251109

  4. Maternal effects shape dynamic trajectories of reproductive allocation in the ladybird Coleomegilla maculata.

    PubMed

    Vargas, G; Michaud, J P; Nechols, J R

    2012-10-01

    We followed lifetime trajectories of reproductive allocation in Coleomegilla maculata females of three different size classes produced by rearing beetles on three different daily larval feeding regimes (30 min, 6 h or ad libitum access to eggs of Ephestia kuehniella). We hypothesized that small females would produce fewer and smaller eggs than larger females and that reproductive effort would decline with female age. Females were mated with a male from the same treatment and then isolated with ad libitum food for their entire adult lives. Egg size increased over time in all treatments; small females started off laying the smallest eggs, but increased egg size more rapidly than larger females, until all treatments converged on a similar egg size around the 20th day of oviposition. Large females realized a larger proportion of their fecundity early in life, but smaller females increased daily fecundity over time. Reproductive effort (egg mass/body mass) did not decline over 30 oviposition days; it remained constant in large females, but increased among small and medium females, suggesting gradual compensation for larval food deprivation. An increase in egg size with maternal age may be an adaptive strategy to maximize fitness on ephemeral patches of aphid prey, assuming females reproduce in a single aphid outbreak and that offspring produced later in the aphid cycle experience greater competition and risk of mortality compared to those produced earlier. We demonstrate for the first time in Coleoptera that dynamic changes in both egg size and number occur as a function of female age and illustrate that such changes are constrained by larval feeding histories via their effects on maternal body size.

  5. Tradeoffs in basal area growth and reproduction shift over the lifetime of a long-lived tropical species.

    PubMed

    Staudhammer, Christina L; Wadt, Lúcia H O; Kainer, Karen A

    2013-09-01

    Understanding of the extent to which reproductive costs drive growth largely derives from reproductively mature temperate trees in masting and non-masting years. We modeled basal area increment (BAI) and explored current growth-reproduction tradeoffs and changes in such allocation over the life span of a long-lived, non-masting tropical tree. We integrated rainfall and soil variables with data from 190 Bertholletia excelsa trees of different diameter at breast height (DBH) sizes, crown characteristics, and liana loads, quantifying BAI and reproductive output over 4 and 6 years, respectively. While rainfall explains BAI in all models, regardless of DBH class or ontogenic stage, light (based on canopy position and crown form) is most critical in the juvenile (5 cm ≤ DBH < 50 cm) phase. Suppressed trees are only present as juveniles and grow ten times slower (1.45 ± 2.73 m(2) year(-1)) than trees in dominant and co-dominant positions (13.25 ± 0.82 and 12.90 ± 1.35 m(2) year(-1), respectively). Additionally, few juvenile trees are reproductive, and those that are, demonstrate reduced growth, as do reproductive trees in the next 50 to 100 cm DBH class, suggesting growth-reproduction tradeoffs. Upon reaching the canopy, however, and attaining a sizeable girth, this pattern gradually shifts to one where BAI and reproduction are influenced independently by variables such as liana load, crown size and soil properties. At this stage, BAI is largely unaffected by fruit production levels. Thus, while growth-reproduction tradeoffs clearly exist during early life stages, effects of reproductive allocation diminish as B. excelsa increases in size and maturity. PMID:23404069

  6. Effects of carbofuran on growth, biomass allocation, and intraspecific competition in Bouteloua gracilis.

    PubMed

    Ingham, R E; Detling, J K

    1982-01-01

    Growth, biomass allocation and competition between blue grama plants were examined with and without application of carbofuran, a pesticide which has been used to study insect and nematode effects on primary production. Carbofuran had no apparent effect on total plant growth, biomass allocation, or competition between neighboring plants.

  7. Reproductive allocation and output in herbaceous annuals of the genera Polygonum, Ipomoea, and Cassia in elevated CO[sub 2] environments

    SciTech Connect

    Farnsworth, E.J.; Bazzaz, F.A. )

    1994-06-01

    In assessing the capacity of plants to adapt to rapidly changing global climate, we must elucidate the impacts of elevated carbon dioxide on reproduction, fitness and evolution. We investigated how elevated CO[sub 2] influenced reproduction and growth of plants exhibiting a range of floral displays, the implications of shifts in allocation for fitness in these species, and whether related taxa would show similar patterns of response. Three herbaceous, annual species each of the genera Polygonum, Ipomoea, and Cassia were grown under 350 or 700 ppm CO[sub 2]. Vegetative growth and reproductive output were non-destructively measured throughout the full life span, and biomass calibrated with a subsample harvest at first flowering. Viability and germination studies of seed progeny were conducted to more precisely characterize fitness. Timecourse and numbers of floral buds, flowers, unripe and abscised fruits differed between CO[sub 2] treatments. Genera differed significantly in their phenological responses to elevated CO[sub 2], Polygonum and Cassia species (but not Ipomoea) showed accelerated, enhanced reproduction. Elevated CO[sub 2] ameliorated trade-offs between vegetative and floral production. However, seed [open quotes]quality[close quotes] and fitness were not always directly correlated with quantity produced. Species within general responded more consistently to CO[sub 2], indicating that phylogeny and life form may be general predictors of performance under global change.

  8. Optimal defense: snails avoid reproductive parts of the lichen Lobaria scrobiculata due to internal defense allocation.

    PubMed

    Asplund, Johan; Solhaug, Knut Asbjørn; Gauslaa, Yngvar

    2010-10-01

    The optimal defense theory (ODT) deals with defensive compounds improving fitness of a particular organism. It predicts that these compounds are allocated in proportion to the risk for a specific plant tissue being attacked and this tissue's value for plant fitness. As the benefit of defense cannot easily be measured in plants, the empirical evidence for ODT is limited. However, lichens are unique in the sense that their carbon-based secondary compounds can nondestructively be removed or reduced in concentration by acetone rinsing. By using such an extraction protocol, which is lethal to plants, we have tested the ODT by studying lichens instead of plants as photosynthetically active organisms. Prior to acetone rinsing, we found five times higher concentration of meta-scrobiculin in the reproductive parts (soralia) of Lobaria scrobiculata compared to somatic parts of this foliose epiphytic lichen species. At this stage, the lichen-feeding snail Cochlodina laminata avoided the soralia. However, after removal of secondary compounds, the snail instead preferred the soralia. In this way, we have successfully shown that grazing pattern inversely reflects the partitioning of the secondary compounds that have a documented deterring effect. Thus our study provides strong and novel evidence for the ODT.

  9. Energy allocation during the maturation of adults in a long-lived insect: implications for dispersal and reproduction.

    PubMed

    David, G; Giffard, B; van Halder, I; Piou, D; Jactel, H

    2015-10-01

    Energy allocation strategies have been widely documented in insects and were formalized in the context of the reproduction process by the terms 'capital breeder' and 'income breeder'. We propose here the extension of this framework to dispersal ability, with the concepts of 'capital disperser' and 'income disperser', and explore the trade-off in resource allocation between dispersal and reproduction. We hypothesized that flight capacity was sex-dependent, due to a trade-off in energy allocation between dispersal and egg production in females. We used Monochamus galloprovincialis as model organism, a long-lived beetle which is the European vector of the pine wood nematode. We estimated the flight capacity with a flight mill and used the number of mature eggs as a proxy for the investment in reproduction. We used the ratio between dry weights of the thorax and the abdomen to investigate the trade-off. The probability of flying increased with the adult weight at emergence, but was not dependent on insect age or sex. Flight distance increased with age in individuals but did not differ between sexes. It was also positively associated with energy allocation to thorax reserves, which increased with age. In females, the abdomen weight and the number of eggs also increase with age with no negative effect on flight capacity, indicating a lack of trade-off. This long-lived beetle has a complex strategy of energy allocation, being a 'capital disperser' in terms of flight ability, an 'income disperser' in terms of flight performance and an 'income breeder' in terms of egg production.

  10. Trade-off between allocation to reproductive ramets and rhizome buds in Carex brevicuspis populations along a small-scale elevational gradient.

    PubMed

    Chen, Xin-sheng; Li, Ya-fang; Xie, Yong-hong; Deng, Zheng-miao; Li, Xu; Li, Feng; Hou, Zhi-yong

    2015-07-31

    The trade-off between allocation to sexual and clonal reproduction in clonal plants is influenced by a variety of environmental factors; however, it has rarely been examined under field conditions. In this study, we investigated the trade-off between two modes of reproduction in Carex brevicuspis C. B. Clarke across a small-scale elevational gradient (21-27 m a.s.l.) at the Dongting Lake wetlands, China. The proportion of biomass allocated to and the density of reproductive ramets were higher at low than at intermediate and high elevations. In contrast, the proportion of biomass allocated to and the density of rhizome buds were lower at low than at intermediate and high elevations. Redundancy analysis showed that sexual reproduction was positively correlated with soil moisture content, soil organic matter, total phosphorus, and pH, and negatively correlated with elevation and ramet density. Our findings suggested that allocation to sexual reproduction is favored in disturbed habitats with fertile soils, whereas allocation to vegetative propagation is favored in stable and competitive habitats. Trade-off between allocation to sexual reproduction and vegetative propagation along an elevational gradient might be a reproductive strategy of C. brevicuspis to adapt to the water level fluctuations in wetland habitats.

  11. Trade-off between allocation to reproductive ramets and rhizome buds in Carex brevicuspis populations along a small-scale elevational gradient.

    PubMed

    Chen, Xin-sheng; Li, Ya-fang; Xie, Yong-hong; Deng, Zheng-miao; Li, Xu; Li, Feng; Hou, Zhi-yong

    2015-01-01

    The trade-off between allocation to sexual and clonal reproduction in clonal plants is influenced by a variety of environmental factors; however, it has rarely been examined under field conditions. In this study, we investigated the trade-off between two modes of reproduction in Carex brevicuspis C. B. Clarke across a small-scale elevational gradient (21-27 m a.s.l.) at the Dongting Lake wetlands, China. The proportion of biomass allocated to and the density of reproductive ramets were higher at low than at intermediate and high elevations. In contrast, the proportion of biomass allocated to and the density of rhizome buds were lower at low than at intermediate and high elevations. Redundancy analysis showed that sexual reproduction was positively correlated with soil moisture content, soil organic matter, total phosphorus, and pH, and negatively correlated with elevation and ramet density. Our findings suggested that allocation to sexual reproduction is favored in disturbed habitats with fertile soils, whereas allocation to vegetative propagation is favored in stable and competitive habitats. Trade-off between allocation to sexual reproduction and vegetative propagation along an elevational gradient might be a reproductive strategy of C. brevicuspis to adapt to the water level fluctuations in wetland habitats. PMID:26228352

  12. Trade-off between allocation to reproductive ramets and rhizome buds in Carex brevicuspis populations along a small-scale elevational gradient

    PubMed Central

    Chen, Xin-sheng; Li, Ya-fang; Xie, Yong-hong; Deng, Zheng-miao; Li, Xu; Li, Feng; Hou, Zhi-yong

    2015-01-01

    The trade-off between allocation to sexual and clonal reproduction in clonal plants is influenced by a variety of environmental factors; however, it has rarely been examined under field conditions. In this study, we investigated the trade-off between two modes of reproduction in Carex brevicuspis C. B. Clarke across a small-scale elevational gradient (21–27 m a.s.l.) at the Dongting Lake wetlands, China. The proportion of biomass allocated to and the density of reproductive ramets were higher at low than at intermediate and high elevations. In contrast, the proportion of biomass allocated to and the density of rhizome buds were lower at low than at intermediate and high elevations. Redundancy analysis showed that sexual reproduction was positively correlated with soil moisture content, soil organic matter, total phosphorus, and pH, and negatively correlated with elevation and ramet density. Our findings suggested that allocation to sexual reproduction is favored in disturbed habitats with fertile soils, whereas allocation to vegetative propagation is favored in stable and competitive habitats. Trade-off between allocation to sexual reproduction and vegetative propagation along an elevational gradient might be a reproductive strategy of C. brevicuspis to adapt to the water level fluctuations in wetland habitats. PMID:26228352

  13. REPRODUCTIVE TOXICITY OF ANDROGENIC GROWTH PROMOTORS IN THE FATHEAD MINNOW

    EPA Science Inventory

    Reproductive Toxicity of Androgenic Growth Promoters in the Fathead Minnow. Jensen, KM*, Kahl, MD, Makynen, EA, Hornung, MW, Ankley, GT. U.S. Environmental Protection Agency, Duluth, MN. Trenbolone acetate is a synthetic steroid which is extensively used in the US as a growth pro...

  14. Genetic correlations between growth and reproductive traits in Zandi sheep.

    PubMed

    Mohammadi, Kourosh; Beigi Nassiri, Mohammad Taghi; Rahmatnejad, Enayat; Abdollahi-Arpanahi, Rostam; Hossaini, Seyed Mohammad Reza; Hagh Nadar, Saman

    2014-06-01

    For the first time, the current study reports the genetic and phenotypic correlations between growth and reproductive traits in Zandi sheep. The data were comprised of 4,309 records of lamb growth traits from 1,378 dams and 273 sires plus 2,588 records of reproductive traits from 577 ewes. These data were extracted from available performance records at Khojir Breeding Station of Zandi sheep in Tehran, Iran, from 1993 to 2008. Correlations were estimated from two animal models in a bivariate analysis using restricted maximum likelihood procedure between lamb growth traits [birth weight (BW), weaning weight at 3 months of age (WW), as well as six-month weight (6 MW)] and ewe reproductive traits [litter size at birth (LSB), litter size at weaning (LSW), total litter weight at birth (TLWB), and total litter weight at weaning (TLWW)]. The genetic correlations between BW and reproductive traits varied from low to high ranges from 0.10 for BW-LSB to 0.86 for BW-TLWB. WW was moderately (0.37) to highly (0.96) correlated with all the reproductive traits. Moreover, the genetic correlations were observed between 6 MW and reproductive traits, varied from 0.19 to 0.95. Relationships between growth and reproductive traits ranged from 0.01 for BW-LSW to 0.28 for BW-TLWB in phenotypic effects. Results indicated that selection to improve WW would have high effect on genetic response in TLWW, and also, these results could be effective for all of the reproductive traits in Zandi sheep.

  15. Genetic correlations between growth and reproductive traits in Zandi sheep.

    PubMed

    Mohammadi, Kourosh; Beigi Nassiri, Mohammad Taghi; Rahmatnejad, Enayat; Abdollahi-Arpanahi, Rostam; Hossaini, Seyed Mohammad Reza; Hagh Nadar, Saman

    2014-06-01

    For the first time, the current study reports the genetic and phenotypic correlations between growth and reproductive traits in Zandi sheep. The data were comprised of 4,309 records of lamb growth traits from 1,378 dams and 273 sires plus 2,588 records of reproductive traits from 577 ewes. These data were extracted from available performance records at Khojir Breeding Station of Zandi sheep in Tehran, Iran, from 1993 to 2008. Correlations were estimated from two animal models in a bivariate analysis using restricted maximum likelihood procedure between lamb growth traits [birth weight (BW), weaning weight at 3 months of age (WW), as well as six-month weight (6 MW)] and ewe reproductive traits [litter size at birth (LSB), litter size at weaning (LSW), total litter weight at birth (TLWB), and total litter weight at weaning (TLWW)]. The genetic correlations between BW and reproductive traits varied from low to high ranges from 0.10 for BW-LSB to 0.86 for BW-TLWB. WW was moderately (0.37) to highly (0.96) correlated with all the reproductive traits. Moreover, the genetic correlations were observed between 6 MW and reproductive traits, varied from 0.19 to 0.95. Relationships between growth and reproductive traits ranged from 0.01 for BW-LSW to 0.28 for BW-TLWB in phenotypic effects. Results indicated that selection to improve WW would have high effect on genetic response in TLWW, and also, these results could be effective for all of the reproductive traits in Zandi sheep. PMID:24705699

  16. Effect of environment on reproduction and growth of Mysis relicta

    USGS Publications Warehouse

    Beeton, Alfred M.; Gannon, John E.

    1991-01-01

    Published and unpublished data were examined to determine whether the time to first reproduction, brood size, and growth rate of Mysis relicta are related to environmental conditions. Time to first reproduction ranged from 1 year in eutrophic lakes to 4 years in a ultraoligotrophic lake. Mysids in nutrient-rich lakes may have 45 eggs per brood, whereas those in less productive lakes had 10-12 eggs per brood. Growth rates ranged from 1.0 to 1.5 mm/month in productive lakes to only 0.2 mm/month in ultraoligotrophic Lake Tahoe. Some differences in reproduction and growth rate consistent with the above observation occurred between areas of Lakes Tahoe and Michigan that differed in trophic conditions.

  17. Differences in Patterns of Reproductive Allocation between the Sexes in Nicrophorus orbicollis.

    PubMed

    Smith, Ashlee N; Creighton, J Curtis; Belk, Mark C

    2015-01-01

    Organisms are selected to maximize lifetime reproductive success by balancing the costs of current reproduction with costs to future survival and fecundity. Males and females typically face different reproductive costs, which makes comparisons of their reproductive strategies difficult. Burying beetles provide a unique system that allows us to compare the costs of reproduction between the sexes because males and females are capable of raising offspring together or alone and carcass preparation and offspring care represent the majority of reproductive costs for both sexes. Because both sexes perform the same functions of carcass preparation and offspring care, we predict that they would experience similar costs and have similar life history patterns. In this study we assess the cost of reproduction in male Nicrophorus orbicollis and compare to patterns observed in females. We compare the reproductive strategies of single males and females that provided pre- and post-hatching parental care. There is a cost to reproduction for both males and females, but the sexes respond to these costs differently. Females match brood size with carcass size, and thus maximize the lifetime number of offspring on a given size carcass. Males cull proportionately more offspring on all carcass sizes, and thus have a lower lifetime number of offspring compared to females. Females exhibit an adaptive reproductive strategy based on resource availability, but male reproductive strategies are not adaptive in relation to resource availability.

  18. Differences in Patterns of Reproductive Allocation between the Sexes in Nicrophorus orbicollis

    PubMed Central

    2015-01-01

    Organisms are selected to maximize lifetime reproductive success by balancing the costs of current reproduction with costs to future survival and fecundity. Males and females typically face different reproductive costs, which makes comparisons of their reproductive strategies difficult. Burying beetles provide a unique system that allows us to compare the costs of reproduction between the sexes because males and females are capable of raising offspring together or alone and carcass preparation and offspring care represent the majority of reproductive costs for both sexes. Because both sexes perform the same functions of carcass preparation and offspring care, we predict that they would experience similar costs and have similar life history patterns. In this study we assess the cost of reproduction in male Nicrophorus orbicollis and compare to patterns observed in females. We compare the reproductive strategies of single males and females that provided pre- and post-hatching parental care. There is a cost to reproduction for both males and females, but the sexes respond to these costs differently. Females match brood size with carcass size, and thus maximize the lifetime number of offspring on a given size carcass. Males cull proportionately more offspring on all carcass sizes, and thus have a lower lifetime number of offspring compared to females. Females exhibit an adaptive reproductive strategy based on resource availability, but male reproductive strategies are not adaptive in relation to resource availability. PMID:26600016

  19. HIV treatment and reproductive health in the health system in Burkina Faso: resource allocation and the need for integration.

    PubMed

    Windisch, Ricarda; de Savigny, Don; Onadja, Geneviève; Somda, Antoine; Wyss, Kaspar; Sié, Ali; Kouyaté, Bocar

    2011-11-01

    Organizational changes, increased funding and the demands of HIV antiretroviral (ARV) treatment create particular challenges for governance in the health sector. We assess resource allocation, policy making and integration of the national responses to ARV provision and reproductive health in Burkina Faso, using national and district budgets related to disease burden, policy documents, organizational structures, and coordination and implementation processes. ARV provision represents the concept of a "crisis scenario", in which reforms are pushed due to a perception of urgent need, whereas the national reproductive health programme, which is older and more integrated, represents a "politics-as-usual scenario". Findings show that the early years of the national response to HIV and AIDS were characterized by new institutions with overlapping functions, and failure to integrate with and strengthen existing structures. National and district budget allocations for HIV compared to other interventions were disproportionately high when assessed against burden of disease. Strategic documents for ARV provision were relatively less developed and referred to, compared to those of the Ministry of Health Directorates for HIV and for Family Health and district health planning teams for reproductive health services. Imbalances and new structures potentially trigger important adverse effects which are difficult to remedy and likely to increase due to the dynamics they create. It therefore becomes crucial, from the outset, to integrate HIV/AIDS funding and responses into health systems.

  20. Changes in cellular energy allocation in Enchytraeus crypticus exposed to copper and silver--linkage to effects at higher level (reproduction).

    PubMed

    Gomes, Susana I L; Soares, Amadeu M V M; Amorim, Mónica J B

    2015-09-01

    Under stressful conditions, organisms often try to detoxify by mobilizing certain energy sources with costs to various functions, e.g. growth or reproduction. Cellular energy allocation (CEA) is a commonly used methodology to evaluate the energetic status of an organism. In the present study, the effects of copper (Cu) and silver (Ag) were evaluated on the total energy budget of Enchytraeus crypticus (Oligochaeta) over periods of exposure (0-2, 2-4 and 4-8 days). The parameters measured were the total energy reserves available (protein, carbohydrate and lipid budgets) and the energy consumption (based on electron transport system activity) being further integrated to obtain the CEA. Results showed that Enchytraeids responded differently to Ag and Cu, mobilizing lipids and proteins in response to Ag and carbohydrates and proteins in response to Cu. Overall, it was possible to distinguish between effect concentrations (reproduction effect concentrations-EC10 and EC50), with EC10 causing an increase in energy consumption (Ec); while for the EC50, the increase in Ec is followed by a steep decrease in Ec, with a corresponding decrease in CEA in the longer exposure periods. These results could be linked with effects at higher levels of biological organization (effects on reproduction) providing evidences that CEA can be used as faster and sensitive endpoints towards metal exposure in E. crypticus. PMID:25971807

  1. How do sink and source activities influence the reproduction and vegetative growth of spring ephemeral herbs under different light conditions?

    PubMed

    Sunmonu, Ninuola; Kudo, Gaku

    2014-07-01

    Spring ephemeral herbs inhabiting deciduous forests commonly complete reproduction and vegetative growth before canopy closure in early summer. Effects of shading by early canopy closure on reproductive output and vegetative growth, however, may vary depending on the seasonal allocation patterns of photosynthetic products between current reproduction and storage for future growth in each species. To clarify the effects of sink-source balance on seed production and bulb growth in a spring ephemeral herb, Gagea lutea, we performed a bract removal treatment (source reduction) and a floral-bud removal treatment (sink reduction) under canopy and open conditions. Leaf carbon fixations did not differ between the forest and open sites and among treatments. Bract carbon fixations were also similar between sites but tended to decrease when floral buds were removed. Seed production was higher under open condition but decreased by the bract-removal treatment under both light conditions. In contrast, bulb growth was independent of light conditions and the bract-removal treatment but increased greatly by the bud-removal treatment. Therefore, leaves and bracts acted as specialized source organs for vegetative and reproductive functions, respectively, but photosynthetic products by bracts were flexibly used for bulb growth when plants failed to set fruits. Extension of bright period was advantageous for seed production (i.e., source limited) but not for vegetative growth (i.e., sink limited) in this species.

  2. Aboveground Tree Growth Varies with Belowground Carbon Allocation in a Tropical Rainforest Environment

    PubMed Central

    Raich, James W.; Clark, Deborah A.; Schwendenmann, Luitgard; Wood, Tana E.

    2014-01-01

    Young secondary forests and plantations in the moist tropics often have rapid rates of biomass accumulation and thus sequester large amounts of carbon. Here, we compare results from mature forest and nearby 15–20 year old tree plantations in lowland Costa Rica to evaluate differences in allocation of carbon to aboveground production and root systems. We found that the tree plantations, which had fully developed, closed canopies, allocated more carbon belowground - to their root systems - than did mature forest. This increase in belowground carbon allocation correlated significantly with aboveground tree growth but not with canopy production (i.e., leaf fall or fine litter production). In contrast, there were no correlations between canopy production and either tree growth or belowground carbon allocation. Enhanced allocation of carbon to root systems can enhance plant nutrient uptake, providing nutrients beyond those required for the production of short-lived tissues such as leaves and fine roots, and thus enabling biomass accumulation. Our analyses support this deduction at our site, showing that enhanced allocation of carbon to root systems can be an important mechanism promoting biomass accumulation during forest growth in the moist tropics. Identifying factors that control when, where and for how long this occurs would help us to improve models of forest growth and nutrient cycling, and to ascertain the role that young forests play in mitigating increased atmospheric carbon dioxide. PMID:24945351

  3. Aboveground tree growth varies with belowground carbon allocation in a tropical rainforest environment.

    PubMed

    Raich, James W; Clark, Deborah A; Schwendenmann, Luitgard; Wood, Tana E

    2014-01-01

    Young secondary forests and plantations in the moist tropics often have rapid rates of biomass accumulation and thus sequester large amounts of carbon. Here, we compare results from mature forest and nearby 15-20 year old tree plantations in lowland Costa Rica to evaluate differences in allocation of carbon to aboveground production and root systems. We found that the tree plantations, which had fully developed, closed canopies, allocated more carbon belowground - to their root systems - than did mature forest. This increase in belowground carbon allocation correlated significantly with aboveground tree growth but not with canopy production (i.e., leaf fall or fine litter production). In contrast, there were no correlations between canopy production and either tree growth or belowground carbon allocation. Enhanced allocation of carbon to root systems can enhance plant nutrient uptake, providing nutrients beyond those required for the production of short-lived tissues such as leaves and fine roots, and thus enabling biomass accumulation. Our analyses support this deduction at our site, showing that enhanced allocation of carbon to root systems can be an important mechanism promoting biomass accumulation during forest growth in the moist tropics. Identifying factors that control when, where and for how long this occurs would help us to improve models of forest growth and nutrient cycling, and to ascertain the role that young forests play in mitigating increased atmospheric carbon dioxide.

  4. The relationship of spectral sensitivity with growth and reproductive response in avian breeders (Gallus gallus)

    PubMed Central

    Yang, Ye-Feng; Jiang, Jing-Song; Pan, Jin-Ming; Ying, Yi-Bin; Wang, Xiao-Shuang; Zhang, Ming-Li; Lu, Min-Si; Chen, Xian-Hui

    2016-01-01

    A previous study demonstrated that birds that are exposed to light at night develop advanced reproductive systems. However, spectrum might also affect the photoperiodic response of birds. The present study was aimed to investigate the effects of spectral composition on the growth and reproductive physiology of female breeders, using pure light-emitting diode spectra. A total of 1,000 newly hatched female avian breeders (Gallus gallus) were equally allocated to white-, red-, yellow-, green- and blue-light treated groups. We found that blue-light treated birds had a greater and faster weight gain than did red- and yellow-light treated birds (P = 0.02 and 0.05). The red light expedited the sexual maturation of the chicks, whose age at sexual maturity was 7 and 14 days earlier than that of the green- and blue-light treated birds, respectively. The accumulative egg production of the red-light treated birds was 9 and 8 eggs more than that of the blue- and green-light treated birds. The peak lay rate of the red-light treated groups was significantly greater than the blue-light treated birds (P = 0.028). In conclusion, exposure to short-wavelength light appears to promote growth of female breeder birds, whereas exposure to long-wavelength light appears to accelerate reproductive performance. PMID:26765747

  5. The relationship of spectral sensitivity with growth and reproductive response in avian breeders (Gallus gallus).

    PubMed

    Yang, Ye-Feng; Jiang, Jing-Song; Pan, Jin-Ming; Ying, Yi-Bin; Wang, Xiao-Shuang; Zhang, Ming-Li; Lu, Min-Si; Chen, Xian-Hui

    2016-01-01

    A previous study demonstrated that birds that are exposed to light at night develop advanced reproductive systems. However, spectrum might also affect the photoperiodic response of birds. The present study was aimed to investigate the effects of spectral composition on the growth and reproductive physiology of female breeders, using pure light-emitting diode spectra. A total of 1,000 newly hatched female avian breeders (Gallus gallus) were equally allocated to white-, red-, yellow-, green- and blue-light treated groups. We found that blue-light treated birds had a greater and faster weight gain than did red- and yellow-light treated birds (P = 0.02 and 0.05). The red light expedited the sexual maturation of the chicks, whose age at sexual maturity was 7 and 14 days earlier than that of the green- and blue-light treated birds, respectively. The accumulative egg production of the red-light treated birds was 9 and 8 eggs more than that of the blue- and green-light treated birds. The peak lay rate of the red-light treated groups was significantly greater than the blue-light treated birds (P = 0.028). In conclusion, exposure to short-wavelength light appears to promote growth of female breeder birds, whereas exposure to long-wavelength light appears to accelerate reproductive performance. PMID:26765747

  6. The relationship of spectral sensitivity with growth and reproductive response in avian breeders (Gallus gallus)

    NASA Astrophysics Data System (ADS)

    Yang, Ye-Feng; Jiang, Jing-Song; Pan, Jin-Ming; Ying, Yi-Bin; Wang, Xiao-Shuang; Zhang, Ming-Li; Lu, Min-Si; Chen, Xian-Hui

    2016-01-01

    A previous study demonstrated that birds that are exposed to light at night develop advanced reproductive systems. However, spectrum might also affect the photoperiodic response of birds. The present study was aimed to investigate the effects of spectral composition on the growth and reproductive physiology of female breeders, using pure light-emitting diode spectra. A total of 1,000 newly hatched female avian breeders (Gallus gallus) were equally allocated to white-, red-, yellow-, green- and blue-light treated groups. We found that blue-light treated birds had a greater and faster weight gain than did red- and yellow-light treated birds (P = 0.02 and 0.05). The red light expedited the sexual maturation of the chicks, whose age at sexual maturity was 7 and 14 days earlier than that of the green- and blue-light treated birds, respectively. The accumulative egg production of the red-light treated birds was 9 and 8 eggs more than that of the blue- and green-light treated birds. The peak lay rate of the red-light treated groups was significantly greater than the blue-light treated birds (P = 0.028). In conclusion, exposure to short-wavelength light appears to promote growth of female breeder birds, whereas exposure to long-wavelength light appears to accelerate reproductive performance.

  7. GROWTH, SURVIVORSHIP, AND REPRODUCTION OF DAPHNIA MIDDENDORFFIANA IN SEVERAL ARCTIC LAKES AND PONDS

    EPA Science Inventory

    The growth, survivorship and reproduction of Arctic region Daphnia middendorffiana was investigated in several lakes and ponds on the tundra in northern Alaska and additionally in a laboratory study. Growth rate equations, reproduction rates and survivorship under natural conditi...

  8. A modeling framework for inferring tree growth and allocation from physiological, morphological and allometric traits.

    PubMed

    Ogle, Kiona; Pacala, Stephen W

    2009-04-01

    Predictions of forest succession, diversity and function require an understanding of how species differ in their growth, allocation patterns and susceptibility to mortality. These processes in turn are affected by allometric constraints and the physiological state of the tree, both of which are coupled to the tree's labile carbon status. Ultimately, insight into the hidden labile pools and the processes affecting the allocation of labile carbon to storage, maintenance and growth will improve our ability to predict tree growth, mortality and forest dynamics. We developed the 'Allometrically Constrained Growth and Carbon Allocation' (ACGCA) model that explicitly couples tree growth, mortality, allometries and labile carbon. This coupling results in (1) a semi-mechanistic basis for predicting tree death, (2) an allocation scheme that simultaneously satisfies allometric relationships and physiology-based carbon dynamics and (3) a range of physiological states that are consistent with tree behavior (e.g., healthy, static, shrinking, recovering, recovered and dead). We present the ACGCA model and illustrate aspects of its behavior by conducting simulations under different forest gap dynamics scenarios and with parameter values obtained for two ecologically dissimilar species: loblolly pine (Pinus taeda L.) and red maple (Acer rubrum L.). The model reproduces growth and mortality patterns of these species that are consistent with their shade-tolerance and succession status. The ACGCA framework provides an alternative, and potentially improved, approach for predicting tree growth, mortality and forest dynamics. PMID:19203984

  9. Extrapituitary growth hormone in the chicken reproductive system.

    PubMed

    Luna, Maricela; Martínez-Moreno, Carlos G; Ahumada-Solórzano, Marisela S; Harvey, Steve; Carranza, Martha; Arámburo, Carlos

    2014-07-01

    Increasing evidence shows that growth hormone (GH) expression is not limited to the pituitary, as it can be produced in many other tissues. It is known that growth hormone (GH) plays a role in the control of reproductive tract development. Acting as an endocrine, paracrine and/or autocrine regulator, GH influences proliferation, differentiation and function of reproductive tissues. In this review we substantiate the local expression of GH mRNA and GH protein, as well as the GH receptor (GHR) in both male and female reproductive tract, mainly in the chicken. Locally expressed GH was found to be heterogeneous, with a 17 kDa variant being predominant. GH secretagogues, such as GHRH and TRH co-localize with GH expression in the chicken testis and induce GH release. In the ovarian follicular granulosa cells, GH and GHR are co-expressed and stimulate progesterone production, which was neutralized by a specific GH antibody. Both testicular and follicular cells in primary cultures were able to synthesize and release GH to the culture medium. We also characterized GH and GH mRNA expression in the hen's oviduct and showed that it had 99.6% sequence identity with pituitary GH. Data suggest local reproductive GH may have important autocrine/paracrine effects.

  10. Insulin-like growth factors and fish reproduction.

    PubMed

    Reinecke, Manfred

    2010-04-01

    Knowledge of fish reproduction is of high relevance to basic fish biology and comparative evolution. Furthermore, fish are excellent biomedical models, and the impact of aquaculture on worldwide food production is steadily increasing. Consequently, research on fish reproduction and the potential modes of its manipulation has become more and more important. Reproduction in fish is regulated by the integration of endogenous neuroendocrine (gonadotropins), endocrine, and autocrine/paracrine signals with exogenous (environmental) factors. The main endocrine regulators of gonadal sex differentiation and function are steroid hormones. However, recent studies suggest that other hormones are also involved. Most prominent among these hormones are the insulin-like growth factors (Igfs), i.e., Igf1, Igf2, and, most recently, Igf3. Thus, the present review deals with the expression patterns and potential physiological functions of Igf1 and Igf2 in male and female gonads. It further considers the potential involvement of growth hormone (Gh) and balances the reasons for endocrine vs. autocrine/paracrine action of the Igfs on the gonads of fish. Finally, this review discusses the early and late development of gonadal Igf1 and Igf2 and whether they are targets of endocrine-disrupting compounds. Future topics for novel research investigation on Igfs and fish reproduction are presented. PMID:19864315

  11. Male Snakes Allocate Time and Energy according to Individual Energetic Status: Body Condition, Steroid Hormones, and Reproductive Behavior in Timber Rattlesnakes, Crotalus horridus.

    PubMed

    Lind, Craig M; Beaupre, Steven J

    2015-01-01

    Life-history theory predicts that organisms will hedge current reproductive investment against potential costs in terms of survivorship and future fecundity. However, little is known regarding the endocrine mechanisms underlying bet-hedging strategies in free-ranging male vertebrates. We examined the relationships among individual energetic status, steroid hormones, mate search, and reproductive behavior in free-ranging male timber rattlesnakes. Snakes were monitored over four active seasons in order to test two hypotheses: (1) males adjust the amount of time and energy allocated toward reproduction according to the level of individual energy stores, and (2) observed condition-dependent reproductive allocation is associated with circulating concentrations of steroid hormones (testosterone and corticosterone) thought to regulate reproductive behaviors in vertebrates. A positive relationship between body condition and testosterone was observed in both the field and the laboratory. Male mate search effort was positively correlated with both body condition and testosterone. Body condition and testosterone concentrations were negatively related to time allocated toward foraging during the breeding season. A strong effect of year was observed in the analysis of testosterone and search effort, suggesting that multiple environmental factors impact hormone production and reproductive investment. Corticosterone was not related to any measured variable. Therefore, our results did not indicate a clear role of corticosterone in mediating observed relationships between energetic status and behavior. Observed relationships are consistent with the hypothesis that males allocate time and energy toward reproduction according to individual energetic status and that testosterone plays a role in mediating the trade-off between current reproductive investment and residual reproductive value.

  12. Male Snakes Allocate Time and Energy according to Individual Energetic Status: Body Condition, Steroid Hormones, and Reproductive Behavior in Timber Rattlesnakes, Crotalus horridus.

    PubMed

    Lind, Craig M; Beaupre, Steven J

    2015-01-01

    Life-history theory predicts that organisms will hedge current reproductive investment against potential costs in terms of survivorship and future fecundity. However, little is known regarding the endocrine mechanisms underlying bet-hedging strategies in free-ranging male vertebrates. We examined the relationships among individual energetic status, steroid hormones, mate search, and reproductive behavior in free-ranging male timber rattlesnakes. Snakes were monitored over four active seasons in order to test two hypotheses: (1) males adjust the amount of time and energy allocated toward reproduction according to the level of individual energy stores, and (2) observed condition-dependent reproductive allocation is associated with circulating concentrations of steroid hormones (testosterone and corticosterone) thought to regulate reproductive behaviors in vertebrates. A positive relationship between body condition and testosterone was observed in both the field and the laboratory. Male mate search effort was positively correlated with both body condition and testosterone. Body condition and testosterone concentrations were negatively related to time allocated toward foraging during the breeding season. A strong effect of year was observed in the analysis of testosterone and search effort, suggesting that multiple environmental factors impact hormone production and reproductive investment. Corticosterone was not related to any measured variable. Therefore, our results did not indicate a clear role of corticosterone in mediating observed relationships between energetic status and behavior. Observed relationships are consistent with the hypothesis that males allocate time and energy toward reproduction according to individual energetic status and that testosterone plays a role in mediating the trade-off between current reproductive investment and residual reproductive value. PMID:26658410

  13. Phenotypic plasticity in growth and fecundity induced by strong population fluctuations affects reproductive traits of female fish.

    PubMed

    Karjalainen, Juha; Urpanen, Olli; Keskinen, Tapio; Huuskonen, Hannu; Sarvala, Jouko; Valkeajärvi, Pentti; Marjomäki, Timo J

    2016-02-01

    Fish are known for their high phenotypic plasticity in life-history traits in relation to environmental variability, and this is particularly pronounced among salmonids in the Northern Hemisphere. Resource limitation leads to trade-offs in phenotypic plasticity between life-history traits related to the reproduction, growth, and survival of individual fish, which have consequences for the age and size distributions of populations, as well as their dynamics and productivity. We studied the effect of plasticity in growth and fecundity of vendace females on their reproductive traits using a series of long-term incubation experiments. The wild parental fish originated from four separate populations with markedly different densities, and hence naturally induced differences in their growth and fecundity. The energy allocation to somatic tissues and eggs prior to spawning served as a proxy for total resource availability to individual females, and its effects on offspring survival and growth were analyzed. Vendace females allocated a rather constant proportion of available energy to eggs (per body mass) despite different growth patterns depending on the total resources in the different lakes; investment into eggs thus dictated the share remaining for growth. The energy allocation to eggs per mass was higher in young than in old spawners and the egg size and the relative fecundity differed between them: Young females produced more and smaller eggs and larvae than old spawners. In contrast to earlier observations of salmonids, a shortage of maternal food resources did not increase offspring size and survival. Vendace females in sparse populations with ample resources and high growth produced larger eggs and larvae. Vendace accommodate strong population fluctuations by their high plasticity in growth and fecundity, which affect their offspring size and consequently their recruitment and productivity, and account for their persistence and resilience in the face of high

  14. Challenges associated with tracking resources allocation for reproductive health in sub-Saharan African countries: the UNFPA/NIDI resource flows project experience.

    PubMed

    Sidze, Estelle M; Beekink, Erik; Maina, Beatrice W

    2015-01-01

    Universal access to reproductive health services entails strengthening health systems, but requires significant resource commitments as well as efficient and effective use of those resources. A number of international organizations and governments in developing countries are putting efforts into tracking the flow of health resources in order to inform resource mobilization and allocation, strategic planning, priority setting, advocacy and general policy making. The UNFPA/NIDI-led Resource Flows Project ("The UNFPA/NIDI RF Project") has conducted annual surveys since 1997 to monitor progress achieved by developing countries in implementing reproductive health financial targets. This commentary summarizes the Project experiences and challenges in gathering data on allocation of resources for reproductive health at the domestic level in sub-Saharan African countries. One key lesson learnt from the Project experience is the need for strengthening tracking mechanisms in sub-Saharan African countries and making information on reproductive health resources and expenditures available, in particular the private sector resources. PMID:26012472

  15. Challenges associated with tracking resources allocation for reproductive health in sub-Saharan African countries: the UNFPA/NIDI resource flows project experience.

    PubMed

    Sidze, Estelle M; Beekink, Erik; Maina, Beatrice W

    2015-05-05

    Universal access to reproductive health services entails strengthening health systems, but requires significant resource commitments as well as efficient and effective use of those resources. A number of international organizations and governments in developing countries are putting efforts into tracking the flow of health resources in order to inform resource mobilization and allocation, strategic planning, priority setting, advocacy and general policy making. The UNFPA/NIDI-led Resource Flows Project ("The UNFPA/NIDI RF Project") has conducted annual surveys since 1997 to monitor progress achieved by developing countries in implementing reproductive health financial targets. This commentary summarizes the Project experiences and challenges in gathering data on allocation of resources for reproductive health at the domestic level in sub-Saharan African countries. One key lesson learnt from the Project experience is the need for strengthening tracking mechanisms in sub-Saharan African countries and making information on reproductive health resources and expenditures available, in particular the private sector resources.

  16. Graph theoretical stable allocation as a tool for reproduction of control by human operators

    NASA Astrophysics Data System (ADS)

    van Nooijen, Ronald; Ertsen, Maurits; Kolechkina, Alla

    2016-04-01

    During the design of central control algorithms for existing water resource systems under manual control it is important to consider the interaction with parts of the system that remain under manual control and to compare the proposed new system with the existing manual methods. In graph theory the "stable allocation" problem has good solution algorithms and allows for formulation of flow distribution problems in terms of priorities. As a test case for the use of this approach we used the algorithm to derive water allocation rules for the Gezira Scheme, an irrigation system located between the Blue and White Niles south of Khartoum. In 1925, Gezira started with 300,000 acres; currently it covers close to two million acres.

  17. Carbon allocation during defoliation: testing a defense-growth trade-off in balsam fir

    PubMed Central

    Deslauriers, Annie; Caron, Laurie; Rossi, Sergio

    2015-01-01

    During repetitive defoliation events, carbon can become limiting for trees. To maintain growth and survival, the resources have to be shared more efficiently, which could result in a trade-off between the different physiological processes of a plant. The objective of this study was to assess the effect of defoliation in carbon allocation of balsam fir [Abies balsamea (L.) Mill.] to test the presence of a trade-off between allocation to growth, carbon storage, and defense. Three defoliation intensities [control (C-trees, 0% defoliation), moderately (M-trees, 41–60%), and heavily (H-trees, 61–80%) defoliated] were selected in order to monitor several variables related to stem growth (wood formation in xylem), carbon storage in stem and needle (non-structural soluble sugars and starch), and defense components in needles (terpenoids compound) from May to October 2011. The concentration of starch was drastically reduced in both wood and leaves of H-trees with a quasi-absence of carbon partitioning to storage in early summer. Fewer kinds of monoterpenes and sesquiterpenes were formed with an increasing level of defoliation indicating a lower carbon allocation for the production of defense. The carbon allocation to wood formation gradually reduced at increasing defoliation intensities, with a lower growth rate and fewer tracheids resulting in a reduced carbon sequestration in cell walls. The hypothesis of a trade-off between the allocations to defense components and to non-structural (NCS) and structural (growth) carbon was rejected as most of the measured variables decreased with increasing defoliation. The starch amount was highly indicative of the tree carbon status at different defoliation intensity and future research should focus on the mechanism of starch utilization for survival and growth following an outbreak. PMID:26029235

  18. Biomass allocation and long-term growth patterns of temperate lianas in comparison with trees.

    PubMed

    Ichihashi, Ryuji; Tateno, Masaki

    2015-08-01

    The host-dependent support habit of lianas is generally interpreted as a strategy designed to reduce resource investment in mechanical tissues; this allows preferential allocation to leaf and stem extension, thereby enhancing productivity and competitive abilities. However, this hypothesis has not been rigorously tested. We examined the aboveground allometries regarding biomass allocation (leaf mass and current-year stem mass (approximated as biomass allocated to extension growth) vs total aboveground mass) and long-term apparent growth patterns (height and aboveground mass vs age, i.e. numbers of growth rings) for nine deciduous liana species in Japan. Lianas had, on average, three- and five-fold greater leaf and current-year stem mass, respectively, than trees for a given aboveground mass, whereas the time course to reach the forest canopy was comparable and biomass accumulation during that period was only one-tenth that of co-occurring canopy trees. The balance between the lengths of yearly stem extension and existing older stems indicated that lianas lost c. 75% of stem length during growth to the canopy, which is probably a consequence of the host-dependent growth. Our observations suggest that, although lianas rely on hosts mechanically, allowing for short-term vigorous growth, this habit requires a large cost and could limit plant growth over protracted periods.

  19. Allocation changes buffer CO2 effect on tree growth since the last ice age

    NASA Astrophysics Data System (ADS)

    Li, G.; Harrison, S. P.; Prentice, I. C. C.; Gerhart, L. M.; Ward, J. K.

    2015-12-01

    Isotopic measurements on junipers growing in southern California during the last glacial, when the ambient atmospheric [CO2] (ca) was ~180 ppm, show the leaf- internal [CO2] (ci) was close to the modern CO2 compensation point for C3 plants. Despite this, stem growth rates were similar to today. Using a coupled light-use efficiency and tree growth model, we show that the ci/ca ratio was stable because both vapor pressure deficit and temperature were decreased with compensating effects. Reduced photorespiration at lower temperatures partly mitigated the effect of low ci on gross primary production, but maintenance of present-day radial growth also required changes in carbon allocation, including a ~25% reduction in below-ground carbon allocation and a ~7% in allocation to leaves. Such a shift was possible due to reduced drought stress. Our findings are consistent with the observed increase in below-ground allocation in FACE experiments and the apparent homoeostasis of measured radial growth as ca increases today; results which our model can also reproduce.

  20. The effect of Bt-transgene introgression on plant growth and reproduction in wild Brassica juncea.

    PubMed

    Liu, Yong-Bo; Darmency, Henry; Stewart, C Neal; Wei, Wei; Tang, Zhi-Xi; Ma, Ke-Ping

    2015-06-01

    This study aims to investigate the relative plant growth and reproduction of insect-resistant and susceptible plants following the introgression of an insect-resistance Bt-transgene from Brassica napus, oilseed rape, to wild Brassica juncea. The second backcrossed generation (BC2) from a single backcross family was grown in pure and mixed stands of Bt-transgenic and non-transgenic siblings under two insect treatments. Various proportions of Bt-transgenic plants were employed in mixed stands to study the interaction between resistant and susceptible plants. In the pure stands, Bt-transgenic BC2 plants performed better than non-transgenic plants with or without insect treatments. In mixed stands, Bt-transgenic BC2 plants produced fewer seeds than their non-Bt counterparts at low proportions of Bt-transgenic BC2 plants in the absence of insects. Reproductive allocation of non-transgenic plants marginally increased with increasing proportions of Bt-transgenic plants under herbivore pressure, which resulted in increased total biomass and seed production per stand. The results showed that the growth of non-transgenic plants was protected by Bt-transgenic plants under herbivore pressure. The Bt-transgene might not be advantageous in mixed stands of backcrossed hybrids; thus transgene introgression would not be facilitated when herbivorous insects are not present. However, a relatively large initial population of Bt-transgenic plants might result in transgene persistence when target herbivores are present. PMID:25487040

  1. The effect of Bt-transgene introgression on plant growth and reproduction in wild Brassica juncea.

    PubMed

    Liu, Yong-Bo; Darmency, Henry; Stewart, C Neal; Wei, Wei; Tang, Zhi-Xi; Ma, Ke-Ping

    2015-06-01

    This study aims to investigate the relative plant growth and reproduction of insect-resistant and susceptible plants following the introgression of an insect-resistance Bt-transgene from Brassica napus, oilseed rape, to wild Brassica juncea. The second backcrossed generation (BC2) from a single backcross family was grown in pure and mixed stands of Bt-transgenic and non-transgenic siblings under two insect treatments. Various proportions of Bt-transgenic plants were employed in mixed stands to study the interaction between resistant and susceptible plants. In the pure stands, Bt-transgenic BC2 plants performed better than non-transgenic plants with or without insect treatments. In mixed stands, Bt-transgenic BC2 plants produced fewer seeds than their non-Bt counterparts at low proportions of Bt-transgenic BC2 plants in the absence of insects. Reproductive allocation of non-transgenic plants marginally increased with increasing proportions of Bt-transgenic plants under herbivore pressure, which resulted in increased total biomass and seed production per stand. The results showed that the growth of non-transgenic plants was protected by Bt-transgenic plants under herbivore pressure. The Bt-transgene might not be advantageous in mixed stands of backcrossed hybrids; thus transgene introgression would not be facilitated when herbivorous insects are not present. However, a relatively large initial population of Bt-transgenic plants might result in transgene persistence when target herbivores are present.

  2. Deciphering the Costs of Reproduction in Mango – Vegetative Growth Matters

    PubMed Central

    Capelli, Mathilde; Lauri, Pierre-Éric; Normand, Frédéric

    2016-01-01

    Irregular fruit production across successive years is a major issue that limits the profitability of most temperate and tropical fruit crops. It is particularly affected by the reciprocal relationships between vegetative and reproductive growth. The concept of the costs of reproduction is defined in terms of losses in the potential future reproductive success caused by current investment in reproduction. This concept, developed in ecology and evolutionary biology, could provide a methodological framework to analyze irregular bearing in fruit crops, especially in relation to the spatial scale at which studies are done. The objective of this study was to investigate the direct effects of reproduction during a growing cycle on reproduction during the following growing cycle and the indirect effects through vegetative growth between these two reproductive events, for four mango cultivars and during two growing cycles. Two spatial scales were considered: the growth unit (GU) and the scaffold branch. Costs of reproduction were detected between two successive reproductive events and between reproduction and vegetative growth. These costs were scale-dependent, generally detected at the GU scale and infrequently at the scaffold branch scale, suggesting partial branch autonomy with respect to processes underlying the effects of reproduction on vegetative growth. In contrast, the relationships between vegetative growth and reproduction were positive at the GU scale and at the scaffold branch scale in most cases, suggesting branch autonomy for the processes, mainly local, underlying flowering and fruiting. The negative effect of reproduction on vegetative growth prevailed over the positive effect of vegetative growth on the subsequent reproduction. The costs of reproduction were also cultivar-dependent. Those revealed at the GU scale were related to the bearing behavior of each cultivar. Our results put forward the crucial role of vegetative growth occurring between two

  3. Appendicularian ecophysiology I: Food concentration dependent clearance rate, assimilation efficiency, growth and reproduction of Oikopleura dioica

    NASA Astrophysics Data System (ADS)

    Lombard, Fabien; Renaud, Florent; Sainsbury, Christopher; Sciandra, Antoine; Gorsky, Gabriel

    2009-11-01

    Three aspects of the appendicularian O. dioica' s ecophysiology were measured here: 1) morphological parameters over a wide range of appendicularian sizes, including mature animals in order to document the morphological characteristics inducing reproduction; 2) clearance rate and assimilation efficiency using feeding incubations with different algal concentrations and 3) the effect of food concentration on growth, mortality and reproduction. The relationship between the body carbon weight and the clearance rate follows a power function, with an exponent of 0.91 (± 0.07). The rate of particles retention increases with the food concentration following a Michaelis-Menten relationship (half-saturation constant = 151 ± 22 µg C l - 1 , maximum clearance rate = 12 ± 1 µg C µg C - 1 d - 1 ). The carbon assimilation efficiency decreases with the increasing food concentration. As a result, appendicularian growth which is limited in concentrations lower than 50 µg C l - 1 is saturated above 100 µg C l - 1 . In immature animals the gonad represents less than 30% of the body volume whereas in mature individuals, its volume varies between 50% and 87% (mean 63%) suggesting that gonad/total volume ratio can be used as indicator of the maturation stages. The gonad weight in mature animals represents 70.3 (± 4.6)% of the total body carbon weight. Two major maturity stages can explain the changes in energy allocation: i) the somatic growth, when less energy is invested in gonad growth when compared to the rest of the body and ii) the maturation phase where most of the assimilated matter is invested in gonad maturation. This process is rapid, lasting only few hours. For this reason we measured completely mature organisms that are generally not measured during the experimental work with appendicularians. In food-limited conditions, the gonad maturation process starts with smaller individuals and ends with smaller reproductive animals having the same gonad to total volume ratio

  4. Water availability and population origin affect the expression of the tradeoff between reproduction and growth in Plantago coronopus.

    PubMed

    Hansen, C F; García, M B; Ehlers, B K

    2013-05-01

    Investment in reproduction and growth represent a classic tradeoff with implication for life history evolution. The local environment can play a major role in the magnitude and evolutionary consequences of such a tradeoff. Here, we examined the investment in reproductive and vegetative tissue in 40 maternal half-sib families from four different populations of the herb Plantago coronopus growing in either a dry or wet greenhouse environment. Plants originated from populations with an annual or a perennial life form, with annuals prevailing in drier habitats with greater seasonal variation in both temperature and precipitation. We found that water availability affected the expression of the tradeoff (both phenotypic and genetic) between reproduction and growth, being most accentuated under dry condition. However, populations responded very differently to water treatments. Plants from annual populations showed a similar response to drought condition with little variation among maternal families, suggesting a history of selection favouring genotypes with high allocation to reproduction when water availability is low. Plants from annual populations also expressed the highest level of plasticity. For the perennial populations, one showed a large variation among maternal families in resource allocation and expressed significant negative genetic correlations between reproductive and vegetative biomass under drought. The other perennial population showed less variation in response to treatment and had trait values similar to those of the annuals, although it was significantly less plastic. We stress the importance of considering intraspecific variation in response to environmental change such as drought, as conspecific plants exhibited very different abilities and strategies to respond to high versus low water availability even among geographically close populations.

  5. Water availability and population origin affect the expression of the tradeoff between reproduction and growth in Plantago coronopus.

    PubMed

    Hansen, C F; García, M B; Ehlers, B K

    2013-05-01

    Investment in reproduction and growth represent a classic tradeoff with implication for life history evolution. The local environment can play a major role in the magnitude and evolutionary consequences of such a tradeoff. Here, we examined the investment in reproductive and vegetative tissue in 40 maternal half-sib families from four different populations of the herb Plantago coronopus growing in either a dry or wet greenhouse environment. Plants originated from populations with an annual or a perennial life form, with annuals prevailing in drier habitats with greater seasonal variation in both temperature and precipitation. We found that water availability affected the expression of the tradeoff (both phenotypic and genetic) between reproduction and growth, being most accentuated under dry condition. However, populations responded very differently to water treatments. Plants from annual populations showed a similar response to drought condition with little variation among maternal families, suggesting a history of selection favouring genotypes with high allocation to reproduction when water availability is low. Plants from annual populations also expressed the highest level of plasticity. For the perennial populations, one showed a large variation among maternal families in resource allocation and expressed significant negative genetic correlations between reproductive and vegetative biomass under drought. The other perennial population showed less variation in response to treatment and had trait values similar to those of the annuals, although it was significantly less plastic. We stress the importance of considering intraspecific variation in response to environmental change such as drought, as conspecific plants exhibited very different abilities and strategies to respond to high versus low water availability even among geographically close populations. PMID:23621367

  6. Does ozone exposure alter growth and carbon allocation of mycorrhizal plants

    SciTech Connect

    Yoshida, L.C.; Gamon, J.A. ); Andersen, C.P. )

    1994-06-01

    Ozone is known to adversely affect plant growth. However, it is less clear how ozone affects belowground processes. This study tests the hypothesis that ozone alters growth and carbon allocation of vesicular arbuscular mycorrhizal (VAM) plants. Two ecotypes of Elymus glaucus (blue wild rye) were exposed to mycorrhizal inoculation and episodic ozone exposures simulating atmospheric conditions in the Los Angeles Basin. Preliminary results show that effects of ozone on growth were subtle. In both ecotypes, growth of aboveground biomass was not affected by ozone while root growth was decreased. In most treatments, mycorrhizal inoculation decreased growth of leaves and stems, but had no significant effect on root growth. Three-way ANOVA tests indicated interactive effects between ecotype, mycorrhiza and ozone. Further experimental work is needed to reveal the biological processes governing these responses.

  7. Watching sexy displays improves hatching success and offspring growth through maternal allocation.

    PubMed

    Loyau, Adeline; Lacroix, Frédéric

    2010-11-22

    Male attractiveness can have tremendous effects on the fitness of his offspring via good genes, but also via enhanced maternal allocation of resources. Yet the proximate mechanisms influencing differential maternal allocation in relation to male sexiness are poorly known. Here, we studied the importance of visual stimulation for maternal allocation in the Houbara bustard, a vulnerable bird species bred in captivity to support wild populations. Artificial insemination allowed controlling for potential confounding factors, such as a male's territory quality, social interactions or sperm quality/quantity, probably linked to mate attractiveness. We show that artificially inseminated females stimulated by highly displaying males increased their hatching success, owing to increased fertilization success. The females also increased the allocation of maternal androgens in their eggs, leading to an increase of circulating testosterone and growth rate in chicks. Hence, visual stimulation of the females can promote differential maternal allocation and favour offspring fitness. Our results further suggest that using artificial insemination for species conservation without appropriate stimulation of the breeding females probably has negative impacts on their breeding performance and therefore on population viability.

  8. Watching sexy displays improves hatching success and offspring growth through maternal allocation.

    PubMed

    Loyau, Adeline; Lacroix, Frédéric

    2010-11-22

    Male attractiveness can have tremendous effects on the fitness of his offspring via good genes, but also via enhanced maternal allocation of resources. Yet the proximate mechanisms influencing differential maternal allocation in relation to male sexiness are poorly known. Here, we studied the importance of visual stimulation for maternal allocation in the Houbara bustard, a vulnerable bird species bred in captivity to support wild populations. Artificial insemination allowed controlling for potential confounding factors, such as a male's territory quality, social interactions or sperm quality/quantity, probably linked to mate attractiveness. We show that artificially inseminated females stimulated by highly displaying males increased their hatching success, owing to increased fertilization success. The females also increased the allocation of maternal androgens in their eggs, leading to an increase of circulating testosterone and growth rate in chicks. Hence, visual stimulation of the females can promote differential maternal allocation and favour offspring fitness. Our results further suggest that using artificial insemination for species conservation without appropriate stimulation of the breeding females probably has negative impacts on their breeding performance and therefore on population viability. PMID:20538650

  9. Effect of protein supplementation and forage allowance on the growth and reproduction of beef heifers grazing stockpiled tall fescue.

    PubMed

    Lyons, S E; Shaeffer, A D; Drewnoski, M E; Poore, M H; Poole, D H

    2016-04-01

    Stockpiled tall fescue can provide adequate winter forage for beef cattle, although unsupplemented replacement heifers may display marginal performance before breeding. The objective of this study was to determine if protein supplementation and/or additional forage improves growth and reproductive performance of replacement heifers grazing stockpiled fescue. Cattle averaging 272 ± 1.59 kg were stratified by BW and then randomly assigned to 1 of 4 plots within a pasture replication. Treatment combinations were assigned in a 2 × 2 factorial arrangement and included 1) a conservative forage allocation ("normal," targeting 85% forage use) and mineral supplement (normal forage allocation with mineral supplement [FM]), 2) normal forage allocation with protein tub (FT), 3) more liberal forage allocation ("extra," targeting 70% forage use) and mineral supplement (extra forage allocation with mineral supplement [EM]), and 4) "extra forage allocation with protein tub (ET). Treatments were administered for 8 wk from early November to early January. Heifers were fed fescue hay for 1 wk before breeding in late January. Heifers were synchronized with the 7-d CO-Synch + controlled internal drug release device protocol and inseminated in late January. Heifers were checked for pregnancy by ultrasonography at 35 and 90 d after AI. Main and interaction effects between the 2 treatments were determined. Total supplement intake was greater for protein tub than mineral supplement (0.36 vs. 0.11 kg·heifer·d, respectively; < 0.0001), and the additional dietary protein in the tub groups resulted in greater serum urea N concentrations ( < 0.0001; 8.15 vs. 10.4 mg/dL for mineral and protein tub, respectively). Forage utilization efficiency was greater for normal than extra forage allocation (74.7 vs. 65.8%, respectively; < 0.0001). Main effects of both treatments on ADG were significant ( < 0.0001; 0.28, 0.43, 0.43, and 0.51 kg·heifer·d for FM, FT, EM, and ET, respectively). There was

  10. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana.

    PubMed

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W; Ryu, Choong-Min

    2015-09-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation. PMID:26361480

  11. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana

    PubMed Central

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W.; Ryu, Choong-Min

    2015-01-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation. PMID:26361480

  12. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana.

    PubMed

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W; Ryu, Choong-Min

    2015-09-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation.

  13. Growth and reproduction of earthworms in ultramafic soils.

    PubMed

    Maleri, R; Reinecke, S A; Mesjasz-Przybylowicz, J; Reinecke, A J

    2007-04-01

    Ultramafic soils are characterized by high concentrations of heavy metals of natural origin-such as chromium, cobalt, manganese, and nickel-as well as a shortage of primary nutrients. This can result in extremely disadvantageous living conditions for all soil-dwelling organisms. Responses to these conditions were addressed by studying growth, cocoon production, and fecundity of earthworms as endpoints of sublethal effects and how this influences the reproductive system and, consequently, population development. Mature specimens of two ecophysiologically different species of earthworms, Eisenia fetida (Savigny) and Aporrectodea caliginosa (Savigny), were exposed for 56 days to an uncontaminated soil and ultramafic soils collected from six ultramafic sites in the Barberton greenstone belt. In all ultramafic soil samples, the specimens of both species grew slower than those in the control soil. In A. caliginosa, an autotomization of the tail section was observed at higher concentrations of heavy metals. At high levels of heavy metals such as manganese, chromium, nickel, and cobalt, a significantly lower cocoon production was recorded for E. fetida, and at medium levels, a time delay in cocoon production was found. A. caliginosa showed an increase in production at medium levels and a decrease at high levels of heavy metals. In both species, no correlation between growth and cocoon viability was found, indicating different target levels for toxicants present in ultramafic soils. To determine effects of these soils on population dynamics, hatching success may be a more useful endpoint of reproduction. PMID:17354041

  14. Food restriction alters energy allocation strategy during growth in tobacco hornworms (Manduca sexta larvae).

    PubMed

    Jiao, Lihong; Amunugama, Kaushalya; Hayes, Matthew B; Jennings, Michael; Domingo, Azriel; Hou, Chen

    2015-08-01

    Growing animals must alter their energy budget in the face of environmental changes and prioritize the energy allocation to metabolism for life-sustaining requirements and energy deposition in new biomass growth. We hypothesize that when food availability is low, larvae of holometabolic insects with a short development stage (relative to the low food availability period) prioritize biomass growth at the expense of metabolism. Driven by this hypothesis, we develop a simple theoretical model, based on conservation of energy and allometric scaling laws, for understanding the dynamic energy budget of growing larvae under food restriction. We test the hypothesis by manipulative experiments on fifth instar hornworms at three temperatures. At each temperature, food restriction increases the scaling power of growth rate but decreases that of metabolic rate, as predicted by the hypothesis. During the fifth instar, the energy budgets of larvae change dynamically. The free-feeding larvae slightly decrease the energy allocated to growth as body mass increases and increase the energy allocated to life sustaining. The opposite trends were observed in food restricted larvae, indicating the predicted prioritization in the energy budget under food restriction. We compare the energy budgets of a few endothermic and ectothermic species and discuss how different life histories lead to the differences in the energy budgets under food restriction. PMID:26105046

  15. Food restriction alters energy allocation strategy during growth in tobacco hornworms ( Manduca sexta larvae)

    NASA Astrophysics Data System (ADS)

    Jiao, Lihong; Amunugama, Kaushalya; Hayes, Matthew B.; Jennings, Michael; Domingo, Azriel; Hou, Chen

    2015-08-01

    Growing animals must alter their energy budget in the face of environmental changes and prioritize the energy allocation to metabolism for life-sustaining requirements and energy deposition in new biomass growth. We hypothesize that when food availability is low, larvae of holometabolic insects with a short development stage (relative to the low food availability period) prioritize biomass growth at the expense of metabolism. Driven by this hypothesis, we develop a simple theoretical model, based on conservation of energy and allometric scaling laws, for understanding the dynamic energy budget of growing larvae under food restriction. We test the hypothesis by manipulative experiments on fifth instar hornworms at three temperatures. At each temperature, food restriction increases the scaling power of growth rate but decreases that of metabolic rate, as predicted by the hypothesis. During the fifth instar, the energy budgets of larvae change dynamically. The free-feeding larvae slightly decrease the energy allocated to growth as body mass increases and increase the energy allocated to life sustaining. The opposite trends were observed in food restricted larvae, indicating the predicted prioritization in the energy budget under food restriction. We compare the energy budgets of a few endothermic and ectothermic species and discuss how different life histories lead to the differences in the energy budgets under food restriction.

  16. Food restriction alters energy allocation strategy during growth in tobacco hornworms (Manduca sexta larvae).

    PubMed

    Jiao, Lihong; Amunugama, Kaushalya; Hayes, Matthew B; Jennings, Michael; Domingo, Azriel; Hou, Chen

    2015-08-01

    Growing animals must alter their energy budget in the face of environmental changes and prioritize the energy allocation to metabolism for life-sustaining requirements and energy deposition in new biomass growth. We hypothesize that when food availability is low, larvae of holometabolic insects with a short development stage (relative to the low food availability period) prioritize biomass growth at the expense of metabolism. Driven by this hypothesis, we develop a simple theoretical model, based on conservation of energy and allometric scaling laws, for understanding the dynamic energy budget of growing larvae under food restriction. We test the hypothesis by manipulative experiments on fifth instar hornworms at three temperatures. At each temperature, food restriction increases the scaling power of growth rate but decreases that of metabolic rate, as predicted by the hypothesis. During the fifth instar, the energy budgets of larvae change dynamically. The free-feeding larvae slightly decrease the energy allocated to growth as body mass increases and increase the energy allocated to life sustaining. The opposite trends were observed in food restricted larvae, indicating the predicted prioritization in the energy budget under food restriction. We compare the energy budgets of a few endothermic and ectothermic species and discuss how different life histories lead to the differences in the energy budgets under food restriction.

  17. Gravitational Effects on Reproduction, Growth, and Development of Mammals

    NASA Technical Reports Server (NTRS)

    Oyama, J.

    1985-01-01

    The broad objective of this research program is to determine the role which gravity plays in the growth and development of mammalian animals. Current studies are focused on the effects of graded hypergravitatinal field intensities on mice, rats and other small sized laboratory animals using the chronic centrifugation technique. They include studies on reproduction and prenatal and postnatel growth and development. Among the important questions addressed are: (1) what stage or stages in animal development are affected by hypergravity and what are the effects? (2) is there a minimum or critical body size for hypergravity to produce a significant effect on growth and development? (3) are there field intensity thresholds for the preceding questions? From analysis of the body masses at birth of rats conceived and allowed to undergo gestation under 2.1G and under normal gravity (1G), it was found that there was no significant difference between the two groups. Futhermore, their growth rates postnatally were the same until they reached a body mass of approximately 50 grams when the 2.1G group showed a significantly slower rate. Results from these studies support the conclusion that prenatal as well as the early postnatal stages of growth and development of the rat are refractory to hyper-G.

  18. Does the silver moss Bryum argenteum exhibit sex-specific patterns in vegetative growth rate, asexual fitness or prezygotic reproductive investment?

    PubMed Central

    Horsley, Kimberly; Stark, Lloyd R.; McLetchie, D. Nicholas

    2011-01-01

    Background and Aims Expected life history trade-offs associated with sex differences in reproductive investment are often undetected in seed plants, with the difficulty arising from logistical issues of conducting controlled experiments. By controlling genotype, age and resource status of individuals, a bryophyte was assessed for sex-specific and location-specific patterns of vegetative, asexual and sexual growth/reproduction across a regional scale. Methods Twelve genotypes (six male, six female) of the dioecious bryophyte Bryum argenteum were subcultured to remove environmental effects, regenerated asexually to replicate each genotype 16 times, and grown over a period of 92 d. Plants were assessed for growth rates, asexual and sexual reproductive traits, and allocation to above- and below-ground regenerative biomass. Key Results The degree of sexual versus asexual reproductive investment appears to be under genetic control, with three distinct ecotypes found in this study. Protonemal growth rate was positively correlated with asexual reproduction and sexual reproduction, whereas asexual reproduction was negatively correlated (appeared to trade-off) with vegetative growth (shoot production). No sex-specific trade-offs were detected. Female sex-expressing shoots were longer than males, but the sexes did not differ in growth traits, asexual traits, sexual induction times, or above- and below-ground biomass. Males, however, had much higher rates of inflorescence production than females, which translated into a significantly higher (24x) prezygotic investment for males relative to females. Conclusions Evidence for three distinct ecotypes is presented for a bryophyte based on regeneration traits. Prior to zygote production, the sexes of this bryophyte did not differ in vegetative growth traits but significantly differed in reproductive investment, with the latter differences potentially implicated in the strongly biased female sex ratio. The disparity between males and

  19. Effects of growth hormone overexpression and growth hormone resistance on neuroendocrine and reproductive functions in transgenic and knock-out mice.

    PubMed

    Bartke, A; Chandrashekar, V; Turyn, D; Steger, R W; Debeljuk, L; Winters, T A; Mattison, J A; Danilovich, N A; Croson, W; Wernsing, D R; Kopchick, J J

    1999-11-01

    Transgenic mice overexpressing growth hormone (GH) exhibit alterations in the function of the hypothalamic-pituitary-gonadal (HPG) axis and the H-P-adrenal axis. Alterations in the turnover of hypothalamic neurotransmitters, in plasma hormone levels, and in regulation of their release are associated with reproductive deficits, particularly in females. Results reported after publication of our minireview on this subject provided evidence that GH-transgenic mice have increased binding of GH to GH binding proteins in plasma, are hyperinsulinemic and insulin resistant, and have major alterations in energy budgets with increased allocation to growth. Reduced life span and fertility of these animals may be related to insufficient allocation of energy to reproduction and maintenance. Growth hormone resistance induced by transgenic expression of an antagonistic bGH analog or by targeted disruption (knock-out, KO) of the GH receptor (GH-R) gene leads to dramatic suppression of plasma levels of insulin-like growth factor-1 (IGF-1), and dwarf phenotype due to reduced growth and increased adiposity. In both models of GH resistance, there are marked reproductive deficits in females, decline of breeding performance of males, and alterations in the function of the HPG axis. In GH-R-KO females, puberty is delayed, and litter size is reduced. Fetal weights are reduced whereas placental weights are increased, and the weight of newborn pups is reduced despite an increase in the length of gestation. In GH-R-KO males, copulatory behavior and fertility are reduced, plasma PRL is elevated, and responses to luteinizing hormone releasing hormone (LHRH) in vivo and to LH in vitro are suppressed. However, reproductive deficits in GH-R-KO mice are very mild when compared to those described previously in IGF-KO animals. Apparently, the amounts of IGF-1 that may be produced locally in the absence of GH stimulation are sufficient for sexual maturation and fertility in both sexes, whereas

  20. [Effects of Cuscuta australis parasitism on the growth, reproduction and defense of Solidago canadensis].

    PubMed

    Yang, Bei-fen; Du, Le-shan; Li, Jun-min

    2015-11-01

    In order to find out how parasitic Cuscuta australis influences the growth and reproduction of Solidago canadensis, the effects of the parasitism of C. australis on the morphological, growth and reproductive traits of S. canadensis were examined and the relationships between the biomass and the contents of the secondary metabolites were analyzed. The results showed that the parasitism significantly reduced the plant height, basal diameter, root length, root diameter, root biomass, stem biomass, leaf biomass, total biomass, number of inflorescences branches, axis length of inflorescence, and number of inflorescence. In particular, plant height, number of inflorescence and the stem biomass of parasitized S. canadensis were only 1/2, 1/5 and 1/8 of non-parasitized plants, respectively. There was no significant difference of plant height, root length, stem biomass and total biomass between plants parasitized with high and low intensities. But the basal diameter, root volume, leaf biomass, root biomass, the number of inflorescences branches, axis length of inflorescence and number of inflorescence of S. canadensis parasitized with high intensity were significantly lower than those of plants parasitized with low intensity. The parasitism of C. australis significantly increased the tannins content in the root and the flavonoids content in the stem of S. canadensis. The biomass of S. canadensis was significantly negatively correlated with the tannin content in the root and the flavonoids content in the stem. These results indicated that the parasitism of C. australis could inhibit the growth of S. canadensis by changing the resources allocation patterns as well as reducing the resources obtained by S. canadensis. PMID:26915184

  1. Onset of and recovery from nitrogen stress during reproductive growth of soybean

    NASA Technical Reports Server (NTRS)

    Henry, L. T.; Raper, C. D. Jr; Rideout, J. W.; Raper CD, J. r. (Principal Investigator)

    1992-01-01

    Photosynthetic rates and allocation of dry matter, nitrogen, and nonstructural carbohydrates were determined during onset of and recovery from a nitrogen stress for reproductive soybean (Glycine max [L.] Merrill cv Ransom) plants. Until the beginning of seed fill, non-nodulated plants were grown in flowing solution culture with 1.0 mM NO3- in a complete nutrient solution. One set of plants then was transferred to minus-nitrogen solution for 24 d of seed fill; a second set was transferred to a minus-nitrogen solution for 14 d followed by return to the complete solution with 1.0 mM NO3- for the remaining 10 d of seed fill; and a third set was continued on the complete solution. Net CO2 exchange rates of individual leaves, which remained nearly constant during seed fill for nonstressed plants, declined at an accelerated rate during onset of nitrogen stress as the specific content of reduced nitrogen in the leaves was decreased by remobilization of nitrogen to support pod growth. The rate of nitrogen remobilization out of leaves initially was relatively greater than the decrease in photosynthetic rate. While rate of pod growth declined in response to the developing nitrogen stress, photosynthetic assimilation of carbon exceeded reproductive demand and nonstructural carbohydrates accumulated within tissues. Following resupply of exogenous NO3-, specific rate of NO3- uptake by roots was enhanced relative to nonstressed plants. While there was little increase in content of reduced nitrogen in leaves, net remobilization of nitrogen out of leaves ceased, and the decline in photosynthetic rate stabilized at about 51% of that for nonstressed plants. This level of photosynthesis, combined with the availability of elevated pools of carbohydrates accumulated during stress, was sufficient to support the increases in both the specific rates of NO3- uptake and the rate of pod growth during recovery.

  2. Onset of and recovery from nitrogen stress during reproductive growth of soybean.

    PubMed

    Henry, L T; Raper, C D; Rideout, J W

    1992-01-01

    Photosynthetic rates and allocation of dry matter, nitrogen, and nonstructural carbohydrates were determined during onset of and recovery from a nitrogen stress for reproductive soybean (Glycine max [L.] Merrill cv Ransom) plants. Until the beginning of seed fill, non-nodulated plants were grown in flowing solution culture with 1.0 mM NO3- in a complete nutrient solution. One set of plants then was transferred to minus-nitrogen solution for 24 d of seed fill; a second set was transferred to a minus-nitrogen solution for 14 d followed by return to the complete solution with 1.0 mM NO3- for the remaining 10 d of seed fill; and a third set was continued on the complete solution. Net CO2 exchange rates of individual leaves, which remained nearly constant during seed fill for nonstressed plants, declined at an accelerated rate during onset of nitrogen stress as the specific content of reduced nitrogen in the leaves was decreased by remobilization of nitrogen to support pod growth. The rate of nitrogen remobilization out of leaves initially was relatively greater than the decrease in photosynthetic rate. While rate of pod growth declined in response to the developing nitrogen stress, photosynthetic assimilation of carbon exceeded reproductive demand and nonstructural carbohydrates accumulated within tissues. Following resupply of exogenous NO3-, specific rate of NO3- uptake by roots was enhanced relative to nonstressed plants. While there was little increase in content of reduced nitrogen in leaves, net remobilization of nitrogen out of leaves ceased, and the decline in photosynthetic rate stabilized at about 51% of that for nonstressed plants. This level of photosynthesis, combined with the availability of elevated pools of carbohydrates accumulated during stress, was sufficient to support the increases in both the specific rates of NO3- uptake and the rate of pod growth during recovery.

  3. [Effects of Cuscuta australis parasitism on the growth, reproduction and defense of Solidago canadensis].

    PubMed

    Yang, Bei-fen; Du, Le-shan; Li, Jun-min

    2015-11-01

    In order to find out how parasitic Cuscuta australis influences the growth and reproduction of Solidago canadensis, the effects of the parasitism of C. australis on the morphological, growth and reproductive traits of S. canadensis were examined and the relationships between the biomass and the contents of the secondary metabolites were analyzed. The results showed that the parasitism significantly reduced the plant height, basal diameter, root length, root diameter, root biomass, stem biomass, leaf biomass, total biomass, number of inflorescences branches, axis length of inflorescence, and number of inflorescence. In particular, plant height, number of inflorescence and the stem biomass of parasitized S. canadensis were only 1/2, 1/5 and 1/8 of non-parasitized plants, respectively. There was no significant difference of plant height, root length, stem biomass and total biomass between plants parasitized with high and low intensities. But the basal diameter, root volume, leaf biomass, root biomass, the number of inflorescences branches, axis length of inflorescence and number of inflorescence of S. canadensis parasitized with high intensity were significantly lower than those of plants parasitized with low intensity. The parasitism of C. australis significantly increased the tannins content in the root and the flavonoids content in the stem of S. canadensis. The biomass of S. canadensis was significantly negatively correlated with the tannin content in the root and the flavonoids content in the stem. These results indicated that the parasitism of C. australis could inhibit the growth of S. canadensis by changing the resources allocation patterns as well as reducing the resources obtained by S. canadensis.

  4. Environmental control of reproductive phenology and the effect of pollen supplementation on resource allocation in the cleistogamous weed, Ruellia nudiflora (Acanthaceae)

    PubMed Central

    Munguía-Rosas, Miguel A.; Parra-Tabla, Victor; Ollerton, Jeff; Cervera, J. Carlos

    2012-01-01

    • Background and Aims Mixed reproductive strategies may have evolved as a response of plants to cope with environmental variation. One example of a mixed reproductive strategy is dimorphic cleistogamy, where a single plant produces closed, obligately self-pollinated (CL) flowers and open, potentially outcrossed (CH) flowers. Frequently, optimal environmental conditions favour production of more costly CH structures whilst economical and reliable CL structures are produced under less favourable conditions. In this study we explore (1) the effect of light and water on the reproductive phenology and (2) the effect of pollen supplementation on resource allocation to seeds in the cleistogamous weed Ruellia nudiflora. • Methods Split-plot field experiments were carried out to assess the effect of shade (two levels: ambient light vs. a reduction of 50 %) and watering (two levels: non-watered vs. watered) on the onset, end and duration of the production of three reproductive structures: CH flowers, CH fruit and CL fruit. We also looked at the effect of these environmental factors on biomass allocation to seeds (seed weight) from obligately self-pollinated flowers (CL), open-pollinated CH flowers and pollen-supplemented CH flowers. • Key Results CH structures were produced for a briefer period and ended earlier under shaded conditions. These conditions also resulted in an earlier production of CL fruit. Shaded conditions also produced greater biomass allocation to CH seeds receiving extra pollen. • Conclusions Sub-optimal (shaded) conditions resulted in a briefer production period of CH structures whilst these same conditions resulted in an earlier production of CL structures. However, under sub-optimal conditions, plants also allocated more resources to seeds sired from CH flowers receiving large pollen loads. Earlier production of reproductive structures and relatively larger seed might improve subsequent success of CL and pollen-supplemented CH seeds

  5. Concentrative nitrogen allocation to sun-lit branches and the effects on whole-plant growth under heterogeneous light environments.

    PubMed

    Sugiura, D; Tateno, M

    2013-08-01

    We investigated the nitrogen and carbohydrate allocation patterns of trees under heterogeneous light environments using saplings of the devil maple tree (Acer diabolicum) with Y-shaped branches. Different branch groups were created: all branches of a sapling exposed to full light (L-branches), all branches exposed to full shade (S-branches), and half of the branches of a sapling exposed to light (HL-branches) and the other half exposed to shade (HS-branches). Throughout the growth period, nitrogen was preferentially allocated to HL-branches, whereas nitrogen allocation to HS-branches was suppressed compared to L- and S-branches. HL-branches with the highest leaf nitrogen content (N(area)) also had the highest rates of growth, and HS-branches with the lowest N(area) had the lowest observed growth rates. In addition, net nitrogen assimilation, estimated using a photosynthesis model, was strongly correlated with branch growth and whole-plant growth. In contrast, patterns of photosynthate allocation to branches and roots were not affected by the light conditions of the other branch. These observations suggest that tree canopies develop as a result of resource allocation patterns, where the growth of sun-lit branches is favoured over shaded branches, which leads to enhanced whole-plant growth in heterogeneous light environments. Our results indicate that whole-plant growth is enhanced by the resource allocation patterns created for saplings in heterogeneous light environments.

  6. Evaluation of bioelectrical impedance analysis (BIA) to measure condition and energy allocated to reproduction in marine fishes

    NASA Astrophysics Data System (ADS)

    Fitzhugh, G. R.; Wuenschel, M. J.; McBride, R. S.

    2010-04-01

    Reliable estimates of fish energy density at specific times prior to spawning may provide suitable proxies for egg production, and thereby help to explain some of the observed annual variation in recruits per spawner. Our goal is to develop and test modifications of BIA technology to measure energy allocation to reproduction for a variety of marine fishes. To date, a newly developed measuring board and probe system stabilized readings, which was demonstrated by a significant reduction in the coefficients of variation for impedance measures. Total body water, wet and dry weights could be predicted with very good precision (r2 = 0.92-0.99) using BIA measures of reactance or resistance for a number of finfish species. While constituent relationships (e.g. body water- body mass functions) did not differ seasonally, we did find that BIA measures are sensitive to body composition changes related to the seasonal spawning cycle. In an examination of monthly samples of tilefish, phase angle decreased below 15° in post-spawning (regressed) females. Such a monthly trend, which suggests available energy had decreased following the spawning season, was not evident from other, more traditional measures of condition including body-muscle water content, Fulton's K or ordinal measures of fat deposition (such as mesenteric fat). These preliminary results show that BIA technology is a promising application for tracking and efficiently predicting energetic condition of marine fishes.

  7. Dynamical Allocation of Cellular Resources as an Optimal Control Problem: Novel Insights into Microbial Growth Strategies.

    PubMed

    Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc; Geiselmann, Johannes; de Jong, Hidde

    2016-03-01

    Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to dynamical environments, using a self-replicator model. We formulate dynamical growth maximization as an optimal control problem that can be solved using Pontryagin's Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-optimal control strategy in dynamical conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for optimizing growth in a changing environment.

  8. Dynamical Allocation of Cellular Resources as an Optimal Control Problem: Novel Insights into Microbial Growth Strategies

    PubMed Central

    Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc

    2016-01-01

    Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to dynamical environments, using a self-replicator model. We formulate dynamical growth maximization as an optimal control problem that can be solved using Pontryagin’s Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-optimal control strategy in dynamical conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for optimizing growth in a changing environment. PMID:26958858

  9. Juvenile compensatory growth has negative consequences for reproduction in Trinidadian guppies (Poecilia reticulata).

    PubMed

    Auer, Sonya K; Arendt, Jeffrey D; Chandramouli, Radhika; Reznick, David N

    2010-08-01

    Compensatory or 'catch-up' growth may be an adaptive mechanism that buffers the growth trajectory of young organisms from deviations caused by reduced food availability. Theory generally assumes that rapid juvenile compensatory growth impacts reproduction only through its positive effects on age and size at maturation, but potential reproductive costs to juvenile compensatory growth remain virtually unexplored. We used a food manipulation experiment to examine the reproductive consequences of compensatory growth in Trinidadian guppies (Poecilia reticulata). Compensatory growth did not affect adult growth rates, litter production rates or investment in offspring size. However, compensatory growth had negative effects on litter size, independent of the effects of female body length, resulting in a 20% decline in offspring production. We discuss potential mechanisms behind this observed cost to reproduction.

  10. Acclimation dynamics and sub-optimality in carbon allocation for C3 and C4 plants subject to growth under elevated CO2

    NASA Astrophysics Data System (ADS)

    Srinivasan, V.; Kumar, P.

    2012-12-01

    Soybean-Maize agro ecosystem covers about 9% of the mainland US and its acclimation response due to climate change has the potential to significantly impact local and regional ecohydrology and climate. C3 and C4 species exhibit different acclimation strategies to elevated CO2 in terms of their carbon assimilation. While C3 species have a direct enhancement in carbon assimilation, C4 species have a mild indirect carbon assimilation enhancement effect due to decreased water stress. However, the fate of the assimilated carbon in terms of its allocation to different plant parts remains unknown to a large extent. This has the potential to alter above and below ground respiration water uptake patterns and crop productivity. In this study, we investigate the dynamics of carbon allocation, translocation and partitioning in C3 and C4 plants under ambient and elevated CO2 conditions using a multi-layer land surface model MLCan (Drewry et al. 2010) and flux and biomass data from Ameriflux and SoyFACE research facilities (Morgan et al. 2004). Furthermore, we compare the observed carbon allocation patterns with an optimal carbon allocation model that maximizes end of season seed yield. Our results show that, only C3 species exhibits acclimation response in carbon allocation under elevated CO2. While the structural, bio-chemical and eco-physiological acclimation effect of elevated CO2 in C3 plants have been documented in earlier studies (Drewry et al. 2010), our study provides a direct evidence of carbon allocation acclimation in C3 plants. Under acclimation C3 plants allocate more carbon to vegetative parts (leaf, stem and root) compared to reproductive part (seed) thus changing their allometric relationships. This explains the apparent lower than expected yields in C3 plants observed in FACE experiments (Morgan et al 2004). Comparison of our results with an optimal carbon allocation model reveals that under ambient CO2 concentrations, C3 and C4 plants allocate sub

  11. Growth and reproduction of the highfin grouper Epinephelus maculatus.

    PubMed

    Rhodes, K L; Taylor, B M; Hernandez-Ortiz, D; Cuetos-Bueno, J

    2016-05-01

    Highfin grouper Epinephelus maculatus sampled in Chuuk, Micronesia, exhibited a moderate growth rate and a relatively short life span compared to other epinephelids of a similar size. Combined gonad and otolith analysis provide preliminary evidence that the species conforms to a protogynous sexual pattern. Mean total length at maturity for females was 308 mm with first age at maturity 2·8 years for females and 4 years for males, which differs from other regional studies. Based on the gonado-somatic index and microscopic analysis of gonads, E. maculatus in Chuuk have a 4 month spawning season (January to April) that corresponds with seasonal lows in sea surface water temperature and overlaps with that of other aggregating epinephelids. The estimated von Bertalanffy growth factor (K) was 0·51 year(-1) , while total mortality was 0·34 year(-1) . Current management for E. maculatus in Chuuk includes a January to May catch, sale and export ban, which overlaps with its reproductive season. The effectiveness of these arrangements will require on-going monitoring to determine whether alternative management strategies are required to ensure population persistence. PMID:27021483

  12. Impact of tree leaf phenology on growth rates and reproduction in the spring flowering species Trillium erectum (Liliaceae).

    PubMed

    Routhier, Marie-Claude; Lapointe, Line

    2002-03-01

    We investigated the impact of overstory tree leaf phenology on growth rates, carbon allocation pattern, and fruit characteristics in the spring flowering species, Trillium erectum (Liliaceae). Air temperature, overstory canopy closure, and T. erectum phenology were monitored at three locations following a latitudinal gradient in Québec, Canada. Northern sugar maple trees leaf out at cooler temperatures than more southern populations, while Trillium development was initiated at the same soil temperature irrespective of the latitude. Therefore, in northern areas, the time between initiation of T. erectum leaf expansion and canopy closure was shorter than in southern areas, which left less time for northern plants to accumulate reserves before canopy closure. Differences in growth patterns were noted between T. erectum populations. From a south-north gradient, investment to reproduction, total plant biomass, and annual growth rate decreased, while specific leaf area and stem height increased, indicating shade acclimation. The length of the high light period in early spring seems to be a determinant for spring flowering plants' growth and reproduction and may explain the northern distribution limit of some of these species. PMID:21665648

  13. Sapling biomass allocation and growth in the understory of a deciduous hardwood forest.

    PubMed

    Delucia, E; Sipe, T; Herrick, J; Maherali, H

    1998-07-01

    Above- and belowground tissues of co-occurring saplings (0.1-1 m height) of Acer saccharum Marsh. (very shade tolerant), Acer rubrum L. (shade tolerant), Fraxinus americana L. (intermediate shade tolerant), and Prunus serotina Ehrh. (shade intolerant) were harvested from a forest understory to test the hypothesis that the pattern of biomass allocation varied predictably with shade-tolerance rank. The placement and length of branches along the main axis were consistent with the formation of a monolayer of foliage for the tolerant and intermediate species. Other morphological characteristics did not vary predictably with shade-tolerance rank. The maintenance of high specific leaf area (SLA; leaf area/leaf mass) and leaf area ratio (LAR; leaf area/sapling mass) is considered important for growth under extreme shade, yet these traits were not clearly related to the shade-tolerance rank of these species. Fraxinus americana, an intermediate species, had the highest LAR and growth rate in the understory, and with the exception of P. serotina, the very shade-tolerant A. saccharum had the lowest LAR. Prunus serotina maintained a large starch-rich tap root and shoot dieback was common, yielding the largest root/shoot ratio for these species. The observed allocation patterns were not similar to the long-standing expectation for the phenotypic response of juvenile trees to shade, but were consistent with three hypothetical "growth strategies" in the understory: (1) the low SLA and LAR of A. saccharum may provide a measure of defense against herbivores and pathogens and thus promote persistence in the understory, (2) the high SLA for F. americana and high LAR for F. americana and A. rubrum may enable these species to achieve high growth rates in shade, and (3) the large carbohydrate stores of P. serotina may poise this species for opportunistic growth following disturbance. The relative importance of resistance to herbivores and pathogens vs. the maintenance of high growth

  14. Sapling biomass allocation and growth in the understory of a deciduous hardwood forest.

    PubMed

    Delucia, E; Sipe, T; Herrick, J; Maherali, H

    1998-07-01

    Above- and belowground tissues of co-occurring saplings (0.1-1 m height) of Acer saccharum Marsh. (very shade tolerant), Acer rubrum L. (shade tolerant), Fraxinus americana L. (intermediate shade tolerant), and Prunus serotina Ehrh. (shade intolerant) were harvested from a forest understory to test the hypothesis that the pattern of biomass allocation varied predictably with shade-tolerance rank. The placement and length of branches along the main axis were consistent with the formation of a monolayer of foliage for the tolerant and intermediate species. Other morphological characteristics did not vary predictably with shade-tolerance rank. The maintenance of high specific leaf area (SLA; leaf area/leaf mass) and leaf area ratio (LAR; leaf area/sapling mass) is considered important for growth under extreme shade, yet these traits were not clearly related to the shade-tolerance rank of these species. Fraxinus americana, an intermediate species, had the highest LAR and growth rate in the understory, and with the exception of P. serotina, the very shade-tolerant A. saccharum had the lowest LAR. Prunus serotina maintained a large starch-rich tap root and shoot dieback was common, yielding the largest root/shoot ratio for these species. The observed allocation patterns were not similar to the long-standing expectation for the phenotypic response of juvenile trees to shade, but were consistent with three hypothetical "growth strategies" in the understory: (1) the low SLA and LAR of A. saccharum may provide a measure of defense against herbivores and pathogens and thus promote persistence in the understory, (2) the high SLA for F. americana and high LAR for F. americana and A. rubrum may enable these species to achieve high growth rates in shade, and (3) the large carbohydrate stores of P. serotina may poise this species for opportunistic growth following disturbance. The relative importance of resistance to herbivores and pathogens vs. the maintenance of high growth

  15. Genetic relationship between growth and reproductive traits in Nellore cattle.

    PubMed

    Santana, M L; Eler, J P; Ferraz, J B S; Mattos, E C

    2012-04-01

    The objective of this study was to evaluate the genetic relationship between postweaning weight gain (PWG), heifer pregnancy (HP), scrotal circumference (SC) at 18 months of age, stayability at 6 years of age (STAY) and finishing visual score at 18 months of age (PREC), and to determine the potential of these traits as selection criteria for the genetic improvement of growth and reproduction in Nellore cattle. The HP was defined as the observation that a heifer conceived and remained pregnant, which was assessed by rectal palpation at 60 days. The STAY was defined as whether or not a cow calved every year up to the age of 6 years, given that she was provided the opportunity to breed. The Bayesian linear-threshold analysis via the Gibbs sampler was used to estimate the variance and covariance components applying a multitrait model. Posterior mean estimates of direct heritability were 0.15 ± 0.00, 0.42 ± 0.02, 0.49 ± 0.01, 0.11 ± 0.01 and 0.19 ± 0.00 for PWG, HP, SC, STAY and PREC, respectively. The genetic correlations between traits ranged from 0.17 to 0.62. The traits studied generally have potential for use as selection criteria in genetic breeding programs. The genetic correlations between all traits show that selection for one of these traits does not imply the loss of the others.

  16. Growth reproductive potential and control strategies for deeproot sedge (Cyperus entreianus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse, growth chamber, and field studies were conducted at Stoneville, MS in 2000-2008 to determine the growth rate, reproductive and overwintering potential, and control of deeproot sedge. In growth chamber studies, deeproot sedge growth rate (height) and plant dry weights were greatest for 2...

  17. The effects of defoliation on carbon allocation: can carbon limitation reduce growth in favour of storage?

    PubMed

    Wiley, Erin; Huepenbecker, Sarah; Casper, Brenda B; Helliker, Brent R

    2013-11-01

    There is no consensus about how stresses such as low water availability and temperature limit tree growth. Sink limitation to growth and survival is often inferred if a given stress does not cause non-structural carbohydrate (NSC) concentrations or levels to decline along with growth. However, trees may actively maintain or increase NSC levels under moderate carbon stress, making the pattern of reduced growth and increased NSCs compatible with carbon limitation. To test this possibility, we used full and half defoliation to impose severe and moderate carbon limitation on 2-year-old Quercus velutina Lam. saplings grown in a common garden. Saplings were harvested at either 3 weeks or 4 months after treatments were applied, representing short- and longer-term effects on woody growth and NSC levels. Both defoliation treatments maintained a lower total leaf area than controls throughout the experiment with no evidence of photosynthetic up-regulation, and resulted in a similar total biomass reduction. While fully defoliated saplings had lower starch levels than controls in the short term, half defoliated saplings maintained control starch levels in both the short and longer term. In the longer term, fully defoliated saplings had the greatest starch concentration increment, allowing them to recover to near-control starch levels. Furthermore, between the two harvest dates, fully and half defoliated saplings allocated a greater proportion of new biomass to starch than did controls. The maintenance of control starch levels in half defoliated saplings indicates that these trees actively store a substantial amount of carbon before growth is carbon saturated. In addition, the allocation shift favouring storage in defoliated saplings is consistent with the hypothesis that, as an adaptation to increasing carbon stress, trees can prioritize carbon reserve formation at the expense of growth. Our results suggest that as carbon limitation increases, reduced growth is not necessarily

  18. Is growth reduction in defoliated trees a consequence of prioritized carbon allocation to reserves?

    NASA Astrophysics Data System (ADS)

    Hoch, Guenter; Schmid, Sandra; Palacio, Sara

    2015-04-01

    Tissue concentrations of carbon reserve compounds are frequently used as proxies for the carbon balance of trees, but the mechanisms regulating the formation of carbon reserves are still under debate. It is often assumed that carbon storage in trees is largely a consequence of surplus carbon supply (reserve accumulation). In contrast, carbon storage might also occur against prevailing carbon demand from other sink activities, like growth (reserve formation), in which case carbon reserve pools might increase even at carbon limitation, and thus, cannot be used as indicators for a tree's carbon supply status. Such a situation might be severe defoliation by herbivores. Especially in evergreen tree species, it has been shown that natural and experimental defoliation leads to a reduction of growth that is proportional to the lost leaf area. Compared to this strong effect on growth, carbon reserve pools (i.e. sugars, starch and storage lipids) of defoliated trees often exert only a temporary decrease immediately after defoliation, while tissue concentrations of carbon reserves return to those of undefoliated trees by the end of the growing season. Within a recent experiment, we investigated, if the growth decline in trees following early season defoliation is the consequence of prioritized carbon allocation to carbon reserves over growth. To test this hypothesis we grew seedlings of evergreen Quecus ilex and deciduous Quercus petraea trees under low (140 ppm), medium (280 ppm) and high (560 ppm) CO2 concentrations and completely defoliated half of the seedlings in each CO2 treatment at the beginning of the growing season. In undefoliated control trees, CO2 had a significant positive effect on the seasonal growth in both species. Defoliation had a strong negative impact on growth in the evergreen Q. illex, but less in the deciduous Q. petraea. In both species, the growth reduction after defoliation relative to undefoliated controls was very similar at all three CO2

  19. Unisexual reproduction enhances fungal competitiveness by promoting habitat exploration via hyphal growth and sporulation.

    PubMed

    Phadke, Sujal S; Feretzaki, Marianna; Heitman, Joseph

    2013-08-01

    Unisexual reproduction is a novel homothallic sexual cycle recently discovered in both ascomycetous and basidiomycetous pathogenic fungi. It is a form of selfing that induces the yeast-to-hyphal dimorphic transition in isolates of the α mating type of the human fungal pathogen Cryptococcus neoformans. Unisexual reproduction may benefit the pathogen by facilitating sexual reproduction in the absence of the opposite a mating type and by generating infectious propagules called basidiospores. Here, we report an independent potential selective advantage of unisexual reproduction beyond genetic exchange and recombination. We competed a wild-type strain capable of undergoing unisexual reproduction with mutants defective in this developmental pathway and found that unisexual reproduction provides a considerable dispersal advantage through hyphal growth and sporulation. Our results show that unisexual reproduction may serve to facilitate access to both nutrients and potential mating partners and may provide a means to maintain the capacity for dimorphic transitions in the environment.

  20. Influence of organic wastes and seasonal environmental factors on growth and reproduction of Eisenia fetida.

    PubMed

    Biradar, Pulikeshi M; Amoji, Sharabanna D

    2003-01-01

    Epigeic earthworms (E. fetida) were cultured on variety of organic wastes amended with cattle manure to determine the influence of diets and the seasonal environmental factors on growth and reproduction. The results showed that growth and reproductive strategies of E. fetida varied with different diets and seasons. Growth and reproduction of worms in all wastes were significantly more in winter and monsoon than in summer season. Hence winter and monsoon seasons could be considered congenial for vermiculture. During all seasons, worm activities were more in cattle manure followed by amended Bengal gram grain husk and Mixed Organic waste by E. fetida. Parthenin containing diet had deleterious effects on cocoon production. PMID:12974416

  1. Growth Hormone and Reproduction: A Review of Endocrine and Autocrine/Paracrine Interactions

    PubMed Central

    Hull, Kerry L.; Harvey, Steve

    2014-01-01

    The somatotropic axis, consisting of growth hormone (GH), hepatic insulin-like growth factor I (IGF-I), and assorted releasing factors, regulates growth and body composition. Axiomatically, since optimal body composition enhances reproductive function, general somatic actions of GH modulate reproductive function. A growing body of evidence supports the hypothesis that GH also modulates reproduction directly, exerting both gonadotropin-dependent and gonadotropin-independent actions in both males and females. Moreover, recent studies indicate GH produced within reproductive tissues differs from pituitary GH in terms of secretion and action. Accordingly, GH is increasingly used as a fertility adjunct in males and females, both humans and nonhumans. This review reconsiders reproductive actions of GH in vertebrates in respect to these new conceptual developments. PMID:25580121

  2. The effect of sediment on survival, growth, reproductive success and bioaccumulation in Neanthes: Summary report

    SciTech Connect

    Gerlinger, T.V.; Fanizzi, M.; Soong, K.; Armstrong, J.; Reish, D.J.

    1995-12-31

    Sediments taken from the vicinity of the County Sanitation Districts of Orange County ocean outfall were tested for survival, growth, reproduction and bioaccumulation of toxicants on the polychaete, Neanthes arenaceodentata. The end points were survival, growth (dry weight), reproductive success (as number of emerged larvae) and bioaccumulation (metals, DDT, PCBs). Ten experiments have been conducted over a 2 year period of which 2 measured reproductive success. The experiments for survival and growth utilized 2--3 week old post-emergence juvenile worms and subjected them to different test sediments including an inert sediment and plain sea water control. Worms were fed during the experiments. Experiments for reproductive success and bioaccumulation consisted of placing 100 juvenile worms each in 10 gallon aquaria together with test sediment for a 35--40 day period. After which, 10--15 pairs were made and each pair was placed in a separate 1 liter beaker together with sediment for the reproductive experiment. The remaining worms in each aquarium were used for chemical analysis. No toxic responses, as measured by survival, growth and reproductive success, were noted at any station during the 2 year study. Growth was generally lower in the inert sediment and sea water controls compared to test sediments indicating that worms were obtaining some nutrients from the sediment. No difference was noted in the number of emerged juveniles in any test container. While worms accumulated metals and organics in their tissue, there was neither a relationship to the station location nor to survival, growth or reproduction.

  3. Investment choices in post-embryonic development: quantifying interactions among growth, regeneration, and asexual reproduction in the annelid Pristina leidyi.

    PubMed

    Zattara, Eduardo E; Bely, Alexandra E

    2013-12-01

    Animals capable of multiple forms of post-embryonic development, such as growth, regeneration, and asexual reproduction, must make choices about which processes to invest in. What strategies guide post-embryonic resource allocation investments? We investigated this question in the annelid Pristina leidyi, which can grow continuously, regenerates well, and reproduces asexually by fission. We found that in this species growth is concentrated in three zones: a subterminal posterior zone (forming new segments), a mid-body zone (forming fission zones), and a previously undescribed subterminal anterior zone at the base of the prostomium (which we suggest continually builds the prostomium through a "conveyor-belt" like process). Body-wide counts of proliferating cells are greater under high food than low food conditions but proliferation patterns themselves are independent of feeding level. Proliferation patterns are strongly affected by amputation, however, with proliferation rapidly shutting-down throughout the body, except at the wound site, following injury. Relative investment to fission and regeneration is highly context-dependent, being sensitive to the position of the cut and the stage of fission. Outcomes range from fission acceleration and regeneration stalling (high fission:regeneration investment) to resorption of fission zones and progression of regeneration (low fission:regeneration investment). Our findings reveal strong interactions between growth, regeneration, and fission and demonstrate a particularly important effect of injury on resource allocation patterns. Patterns of resource investment in P. leidyi show similarities to those described in two other groups that evolved fission independently (naidine annelids and catenulid flatworms), suggesting that similar developmental and physiological contexts may drive convergent evolution of resource allocation strategies. PMID:23913524

  4. Investment choices in post-embryonic development: quantifying interactions among growth, regeneration, and asexual reproduction in the annelid Pristina leidyi.

    PubMed

    Zattara, Eduardo E; Bely, Alexandra E

    2013-12-01

    Animals capable of multiple forms of post-embryonic development, such as growth, regeneration, and asexual reproduction, must make choices about which processes to invest in. What strategies guide post-embryonic resource allocation investments? We investigated this question in the annelid Pristina leidyi, which can grow continuously, regenerates well, and reproduces asexually by fission. We found that in this species growth is concentrated in three zones: a subterminal posterior zone (forming new segments), a mid-body zone (forming fission zones), and a previously undescribed subterminal anterior zone at the base of the prostomium (which we suggest continually builds the prostomium through a "conveyor-belt" like process). Body-wide counts of proliferating cells are greater under high food than low food conditions but proliferation patterns themselves are independent of feeding level. Proliferation patterns are strongly affected by amputation, however, with proliferation rapidly shutting-down throughout the body, except at the wound site, following injury. Relative investment to fission and regeneration is highly context-dependent, being sensitive to the position of the cut and the stage of fission. Outcomes range from fission acceleration and regeneration stalling (high fission:regeneration investment) to resorption of fission zones and progression of regeneration (low fission:regeneration investment). Our findings reveal strong interactions between growth, regeneration, and fission and demonstrate a particularly important effect of injury on resource allocation patterns. Patterns of resource investment in P. leidyi show similarities to those described in two other groups that evolved fission independently (naidine annelids and catenulid flatworms), suggesting that similar developmental and physiological contexts may drive convergent evolution of resource allocation strategies.

  5. Effect of development system on growth and reproductive performance of beef heifers.

    PubMed

    Lardner, H A; Damiran, D; Hendrick, S; Larson, K; Funston, R

    2014-07-01

    Reproductive performance was evaluated in beef heifers born over a 2-yr period to determine the effects of target breeding weight (TBW) and development system (SYS) on growth and subsequent reproductive efficiency. Spring-born Angus heifers (253 ± 0.7 kg) were randomly allocated over 2 consecutive yr (yr 1, n = 80; yr 2, n = 96) to be developed to either 55% (350 kg) of mature BW (moderate gain, MG) or 62% (395 kg) of mature BW (high gain, HG). Each MG and HG group was further assigned to 1 of 2 replicated systems: (1) bale graze bromegrass-alfalfa round bales in field paddocks (BG) or (2) fed bromegrass-alfalfa round bales in drylot pens (DL). Heifers were fed a diet of bromegrass-alfalfa hay (56.9% TDN; 9.8% CP) and barley grain supplement (85.1% TDN; 12.3% CP). After the 202-d development period, heifers were exposed to bulls for a 63-d breeding season. Target BW × SYS interactions were not detected for any measured parameters. During the winter development period, MG heifers had lower (P = 0.01) ADG than HG heifers and MG heifers had lighter (P = 0.01) BW at breeding. The proportion of heifers attaining puberty by 14.5 mo of age was less (P = 0.05) in MG (20 ± 4%) than HG heifers (52 ± 3%). From the end of the 202-d development period to pregnancy diagnosis, ADG was greater (P = 0.04) in MG heifers than HG heifers (0.83 vs. 0.71 kg/d). First-calf pregnancy rates were 86 and 88% for MG and HG heifers, respectively (P = 0.41). Second- and third-calf pregnancy rates of cows, developed in either a MG or HG system as heifers, were not different (P = 0.74; 94.7 vs. 95.9% and 93.8 vs. 93.9%, respectively). Economic analysis revealed a $58 reduced development cost for heifers developed to 55% compared with 62% of mature BW without a loss in reproductive performance. PMID:24778339

  6. Effect of development system on growth and reproductive performance of beef heifers.

    PubMed

    Lardner, H A; Damiran, D; Hendrick, S; Larson, K; Funston, R

    2014-07-01

    Reproductive performance was evaluated in beef heifers born over a 2-yr period to determine the effects of target breeding weight (TBW) and development system (SYS) on growth and subsequent reproductive efficiency. Spring-born Angus heifers (253 ± 0.7 kg) were randomly allocated over 2 consecutive yr (yr 1, n = 80; yr 2, n = 96) to be developed to either 55% (350 kg) of mature BW (moderate gain, MG) or 62% (395 kg) of mature BW (high gain, HG). Each MG and HG group was further assigned to 1 of 2 replicated systems: (1) bale graze bromegrass-alfalfa round bales in field paddocks (BG) or (2) fed bromegrass-alfalfa round bales in drylot pens (DL). Heifers were fed a diet of bromegrass-alfalfa hay (56.9% TDN; 9.8% CP) and barley grain supplement (85.1% TDN; 12.3% CP). After the 202-d development period, heifers were exposed to bulls for a 63-d breeding season. Target BW × SYS interactions were not detected for any measured parameters. During the winter development period, MG heifers had lower (P = 0.01) ADG than HG heifers and MG heifers had lighter (P = 0.01) BW at breeding. The proportion of heifers attaining puberty by 14.5 mo of age was less (P = 0.05) in MG (20 ± 4%) than HG heifers (52 ± 3%). From the end of the 202-d development period to pregnancy diagnosis, ADG was greater (P = 0.04) in MG heifers than HG heifers (0.83 vs. 0.71 kg/d). First-calf pregnancy rates were 86 and 88% for MG and HG heifers, respectively (P = 0.41). Second- and third-calf pregnancy rates of cows, developed in either a MG or HG system as heifers, were not different (P = 0.74; 94.7 vs. 95.9% and 93.8 vs. 93.9%, respectively). Economic analysis revealed a $58 reduced development cost for heifers developed to 55% compared with 62% of mature BW without a loss in reproductive performance.

  7. The Nuclear Receptor DAF-12 Regulates Nutrient Metabolism and Reproductive Growth in Nematodes

    PubMed Central

    Wang, Zhu; Stoltzfus, Jonathan; You, Young-jai; Ranjit, Najju; Tang, Hao; Xie, Yang; Lok, James B.; Mangelsdorf, David J.; Kliewer, Steven A.

    2015-01-01

    Appropriate nutrient response is essential for growth and reproduction. Under favorable nutrient conditions, the C. elegans nuclear receptor DAF-12 is activated by dafachronic acids, hormones that commit larvae to reproductive growth. Here, we report that in addition to its well-studied role in controlling developmental gene expression, the DAF-12 endocrine system governs expression of a gene network that stimulates the aerobic catabolism of fatty acids. Thus, activation of the DAF-12 transcriptome coordinately mobilizes energy stores to permit reproductive growth. DAF-12 regulation of this metabolic gene network is conserved in the human parasite, Strongyloides stercoralis, and inhibition of specific steps in this network blocks reproductive growth in both of the nematodes. Our study provides a molecular understanding for metabolic adaptation of nematodes to their environment, and suggests a new therapeutic strategy for treating parasitic diseases. PMID:25774872

  8. Asexual endophytes in a native grass: Tradeoffs in mortality, growth, reproduction, and alkaloid production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neotyphodium endophytes are asexual, seed-borne fungal symbionts that are thought to interact mutualistically with their grass hosts. Benefits include increased growth, reproduction, and resistance of herbivores via endophytic alkaloids. Although these benefits are well established in infected int...

  9. EFFECTS OF CORPUS CHRISTI BAY SEDIMENTS ON SURVIVAL, GROWTH AND REPRODUCTION OF THE MYSID, MYSIDOPSIS BAHIA

    EPA Science Inventory

    The study described here examined effects on mortality, growth, reproduction, and behavior of Americamysis bahi exposed under extended static conditions to bedded sediments from Corpus Christi Bay.

  10. Stand density, tree social status and water stress influence allocation in height and diameter growth of Quercus petraea (Liebl.).

    PubMed

    Trouvé, Raphaël; Bontemps, Jean-Daniel; Seynave, Ingrid; Collet, Catherine; Lebourgeois, François

    2015-10-01

    Even-aged forest stands are competitive communities where competition for light gives advantages to tall individuals, thereby inducing a race for height. These same individuals must however balance this competitive advantage with height-related mechanical and hydraulic risks. These phenomena may induce variations in height-diameter growth relationships, with primary dependences on stand density and tree social status as proxies for competition pressure and access to light, and on availability of local environmental resources, including water. We aimed to investigate the effects of stand density, tree social status and water stress on the individual height-circumference growth allocation (Δh-Δc), in even-aged stands of Quercus petraea Liebl. (sessile oak). Within-stand Δc was used as surrogate for tree social status. We used an original long-term experimental plot network, set up in the species production area in France, and designed to explore stand dynamics on a maximum density gradient. Growth allocation was modelled statistically by relating the shape of the Δh-Δc relationship to stand density, stand age and water deficit. The shape of the Δh-Δc relationship shifted from linear with a moderate slope in open-grown stands to concave saturating with an initial steep slope in closed stands. Maximum height growth was found to follow a typical mono-modal response to stand age. In open-grown stands, increasing summer soil water deficit was found to decrease height growth relative to radial growth, suggesting hydraulic constraints on height growth. A similar pattern was found in closed stands, the magnitude of the effect however lowering from suppressed to dominant trees. We highlight the high phenotypic plasticity of growth in sessile oak trees that further adapt their allocation scheme to their environment. Stand density and tree social status were major drivers of growth allocation variations, while water stress had a detrimental effect on height in the

  11. Exposure of Enchytraeus albidus to Cd and Zn - changes in cellular energy allocation (CEA) and linkage to transcriptional, enzymatic and reproductive effects.

    PubMed

    Novais, Sara C; Soares, Amadeu M V M; De Coen, Wim; Amorim, Mónica J B

    2013-01-01

    Cellular energy allocation (CEA) is a measure of the energy status of an organism. The effects of Cd and Zn (reproduction EC(50)s and EC(90)s) on the total energy budget of Enchytraeus albidus (Oligochaeta) were assessed through CEA determination, over periods of time from 0 to 8 d. Results showed reduction on the energy reserves for both metals after 2 d exposure. Lipids were the first reserves to be used and carbohydrates were reduced exclusively after Cd exposure. Electron transport system (ETS) activities were enhanced, suggesting increased metabolism and higher energy requirements for metal detoxification. This was supported by previous results at transcription level, where an up-regulation of genes involved in the mitochondrial oxidative phosphorylation was verified. Additionally, the reduction of CEA may be related with the decrease on the reproductive output. These results showed the relevance of integrating various endpoints, which enabled an overview of various processes and to unravel mechanisms of action of chemicals.

  12. Exposure of Enchytraeus albidus to Cd and Zn - changes in cellular energy allocation (CEA) and linkage to transcriptional, enzymatic and reproductive effects.

    PubMed

    Novais, Sara C; Soares, Amadeu M V M; De Coen, Wim; Amorim, Mónica J B

    2013-01-01

    Cellular energy allocation (CEA) is a measure of the energy status of an organism. The effects of Cd and Zn (reproduction EC(50)s and EC(90)s) on the total energy budget of Enchytraeus albidus (Oligochaeta) were assessed through CEA determination, over periods of time from 0 to 8 d. Results showed reduction on the energy reserves for both metals after 2 d exposure. Lipids were the first reserves to be used and carbohydrates were reduced exclusively after Cd exposure. Electron transport system (ETS) activities were enhanced, suggesting increased metabolism and higher energy requirements for metal detoxification. This was supported by previous results at transcription level, where an up-regulation of genes involved in the mitochondrial oxidative phosphorylation was verified. Additionally, the reduction of CEA may be related with the decrease on the reproductive output. These results showed the relevance of integrating various endpoints, which enabled an overview of various processes and to unravel mechanisms of action of chemicals. PMID:23062832

  13. Reproductive allocation in plants as affected by elevated carbon dioxide and other environmental changes: a synthesis using meta-analysis and graphical vector analysis.

    PubMed

    Wang, Xianzhong; Taub, Daniel R; Jablonski, Leanne M

    2015-04-01

    Reproduction is an important life history trait that strongly affects dynamics of plant populations. Although it has been well documented that elevated carbon dioxide (CO2) in the atmosphere greatly enhances biomass production in plants, the overall effect of elevated CO2 on reproductive allocation (RA), i.e., the proportion of biomass allocated to reproductive structures, is little understood. We combined meta-analysis with graphical vector analysis to examine the overall effect of elevated CO2 on RA and how other environmental factors, such as low nutrients, drought and elevated atmospheric ozone (O3), interacted with elevated CO2 in affecting RA in herbaceous plants. Averaged across all species of different functional groups and environmental conditions, elevated CO2 had little effect on RA (-0.9%). RA in plants of different reproductive strategies and functional groups, however, differed in response to elevated CO2. For example, RA in iteroparous wild species decreased by 8%, while RA in iteroparous crops increased significantly (+14%) at elevated CO2. RA was unaffected by CO2 in plants grown with no stress or in low-nutrient soils. RA decreased at elevated CO2 and elevated O3, but increased in response to elevated CO2 in drought-stressed plants, suggesting that elevated CO2 could ameliorate the adverse effect of drought on crop production to some extent. Our results demonstrate that elevated CO2 and other global environmental changes have the potential to greatly alter plant community composition through differential effects on RA of different plant species and thus affect the dynamics of natural and agricultural ecosystems in the future. PMID:25537120

  14. Reproductive allocation in plants as affected by elevated carbon dioxide and other environmental changes: a synthesis using meta-analysis and graphical vector analysis.

    PubMed

    Wang, Xianzhong; Taub, Daniel R; Jablonski, Leanne M

    2015-04-01

    Reproduction is an important life history trait that strongly affects dynamics of plant populations. Although it has been well documented that elevated carbon dioxide (CO2) in the atmosphere greatly enhances biomass production in plants, the overall effect of elevated CO2 on reproductive allocation (RA), i.e., the proportion of biomass allocated to reproductive structures, is little understood. We combined meta-analysis with graphical vector analysis to examine the overall effect of elevated CO2 on RA and how other environmental factors, such as low nutrients, drought and elevated atmospheric ozone (O3), interacted with elevated CO2 in affecting RA in herbaceous plants. Averaged across all species of different functional groups and environmental conditions, elevated CO2 had little effect on RA (-0.9%). RA in plants of different reproductive strategies and functional groups, however, differed in response to elevated CO2. For example, RA in iteroparous wild species decreased by 8%, while RA in iteroparous crops increased significantly (+14%) at elevated CO2. RA was unaffected by CO2 in plants grown with no stress or in low-nutrient soils. RA decreased at elevated CO2 and elevated O3, but increased in response to elevated CO2 in drought-stressed plants, suggesting that elevated CO2 could ameliorate the adverse effect of drought on crop production to some extent. Our results demonstrate that elevated CO2 and other global environmental changes have the potential to greatly alter plant community composition through differential effects on RA of different plant species and thus affect the dynamics of natural and agricultural ecosystems in the future.

  15. Selection of optimal measures of growth and reproduction for the sublethal Leptocheirus plumulosus sediment bioassay

    SciTech Connect

    Gray, B.R.; Wright, R.B.; Duke, B.M.; Farrar, J.D.; Emery, V.L. Jr.; Brandon, D.L.; Moore, D.W.

    1998-11-01

    This article describes the selection process used to identify optimal measures of growth and reproduction for the proposed 28-d sublethal sediment bioassay with the estuarine amphipod Leptocheirus plumulosus. The authors used four criteria (relevance of each measure to its respective endpoint, signal-to-noise ratio, redundancy relative to other measures of the same endpoint, and cost) to evaluate nine growth and seven reproductive measures. Optimal endpoint measures were identified as those receiving relatively high scores for all or most criteria. Measures of growth scored similarly on all criteria, except for cost. The cost of the pooled (female plus male) growth measures was substantially lower than the cost of the female and male growth measures because the latter required more labor (by approx. 25 min per replicate). Pooled dry weight was identified as the optimal growth measure over pooled length because the latter required additional labor and nonstandard software and equipment. Embryo and neonate measures of reproduction exhibited wide differences in labor costs but yielded similar scores for other criteria. In contrast, brooding measures of reproduction scored relatively low on endpoint relevance, signal-to-noise ratio, and redundancy criteria. The authors recommend neonates/survivor as the optimal measure of L. plumulosus reproduction because it exhibited high endpoint relevance and signal-to-noise ratios, was redundant to other reproductive measures, and required minimal time.

  16. Ozone affects gas exchange, growth and reproductive development in Brassica campestris (Wisconsin fast plants).

    PubMed

    Black, V J; Stewart, C A; Roberts, J A; Black, C R

    2007-01-01

    Exposure to ozone (O(3)) may affect vegetative and reproductive development, although the consequences for yield depend on the effectiveness of the compensatory processes induced. This study examined the impact on reproductive development of exposing Brassica campestris (Wisconsin Fast Plants) to ozone during vegetative growth. Plants were exposed to 70 ppb ozone for 2 d during late vegetative growth or 10 d spanning most of the vegetative phase. Effects on gas exchange, vegetative growth, reproductive development and seed yield were determined. Impacts on gas exchange and foliar injury were related to pre-exposure stomatal conductance. Exposure for 2 d had no effect on growth or reproductive characteristics, whereas 10-d exposure reduced vegetative growth and reproductive site number on the terminal raceme. Mature seed number and weight per pod and per plant were unaffected because seed abortion was reduced. The observation that mature seed yield per plant was unaffected by exposure during the vegetative phase, despite adverse effects on physiological, vegetative and reproductive processes, shows that indeterminate species such as B. campestris possess sufficient compensatory flexibility to avoid reductions in seed production. PMID:17803646

  17. Ozone affects gas exchange, growth and reproductive development in Brassica campestris (Wisconsin fast plants).

    PubMed

    Black, V J; Stewart, C A; Roberts, J A; Black, C R

    2007-01-01

    Exposure to ozone (O(3)) may affect vegetative and reproductive development, although the consequences for yield depend on the effectiveness of the compensatory processes induced. This study examined the impact on reproductive development of exposing Brassica campestris (Wisconsin Fast Plants) to ozone during vegetative growth. Plants were exposed to 70 ppb ozone for 2 d during late vegetative growth or 10 d spanning most of the vegetative phase. Effects on gas exchange, vegetative growth, reproductive development and seed yield were determined. Impacts on gas exchange and foliar injury were related to pre-exposure stomatal conductance. Exposure for 2 d had no effect on growth or reproductive characteristics, whereas 10-d exposure reduced vegetative growth and reproductive site number on the terminal raceme. Mature seed number and weight per pod and per plant were unaffected because seed abortion was reduced. The observation that mature seed yield per plant was unaffected by exposure during the vegetative phase, despite adverse effects on physiological, vegetative and reproductive processes, shows that indeterminate species such as B. campestris possess sufficient compensatory flexibility to avoid reductions in seed production.

  18. Early growth, dominance acquisition and lifetime reproductive success in male and female cooperative meerkats.

    PubMed

    English, Sinead; Huchard, Elise; Nielsen, Johanna F; Clutton-Brock, Tim H

    2013-11-01

    In polygynous species, variance in reproductive success is higher in males than females. There is consequently stronger selection for competitive traits in males and early growth can have a greater influence on later fitness in males than in females. As yet, little is known about sex differences in the effect of early growth on subsequent breeding success in species where variance in reproductive success is higher in females than males, and competitive traits are under stronger selection in females. Greater variance in reproductive success has been documented in several singular cooperative breeders. Here, we investigated consequences of early growth for later reproductive success in wild meerkats. We found that, despite the absence of dimorphism, females who exhibited faster growth until nutritional independence were more likely to become dominant, whereas early growth did not affect dominance acquisition in males. Among those individuals who attained dominance, there was no further influence of early growth on dominance tenure or lifetime reproductive success in males or females. These findings suggest that early growth effects on competitive abilities and fitness may reflect the intensity of intrasexual competition even in sexually monomorphic species.

  19. Early growth, dominance acquisition and lifetime reproductive success in male and female cooperative meerkats.

    PubMed

    English, Sinead; Huchard, Elise; Nielsen, Johanna F; Clutton-Brock, Tim H

    2013-11-01

    In polygynous species, variance in reproductive success is higher in males than females. There is consequently stronger selection for competitive traits in males and early growth can have a greater influence on later fitness in males than in females. As yet, little is known about sex differences in the effect of early growth on subsequent breeding success in species where variance in reproductive success is higher in females than males, and competitive traits are under stronger selection in females. Greater variance in reproductive success has been documented in several singular cooperative breeders. Here, we investigated consequences of early growth for later reproductive success in wild meerkats. We found that, despite the absence of dimorphism, females who exhibited faster growth until nutritional independence were more likely to become dominant, whereas early growth did not affect dominance acquisition in males. Among those individuals who attained dominance, there was no further influence of early growth on dominance tenure or lifetime reproductive success in males or females. These findings suggest that early growth effects on competitive abilities and fitness may reflect the intensity of intrasexual competition even in sexually monomorphic species. PMID:24340181

  20. The ontogeny of postmaturation resource allocation in turtles.

    PubMed

    Bowden, R M; Paitz, Ryan T; Janzen, Fredric J

    2011-01-01

    Resource-allocation decisions vary with life-history strategy, and growing evidence suggests that long-lived endothermic vertebrates direct resources toward growth and self-maintenance when young, increasing allocation toward reproductive effort over time. Few studies have tracked the ontogeny of resource allocation (energy, steroid hormones, etc.) in long-lived ectothermic vertebrates, limiting our understanding of the generality of life-history strategies among vertebrates. We investigated how reproductively mature female painted turtles (Chrysemys picta) from two distinct age classes allocated resources over a 4-yr period and whether resource-allocation patterns varied with nesting experience. We examined age-related variation in body size, egg mass, reproductive frequency, and yolk steroids and report that younger females were smaller and allocated fewer resources to reproduction than did older females. Testosterone levels were higher in eggs from younger females, whereas eggs from second (seasonal) clutches contained higher concentrations of progesterone and estradiol. These allocation patterns resulted in older, larger females laying larger eggs and producing second clutches more frequently than their younger counterparts. We conclude that resource-allocation patterns do vary with age in a long-lived ectotherm.

  1. Growth and reproductive patterns of Undaria pinnatifida sporophytes in a cultivation farm in Busan, Korea

    PubMed Central

    Kim, Young Sik; Lee, Soon Jeong

    2006-01-01

    Monthly growth and reproduction of Undaria pinnatifida sporophytes were examined over a period of 5 months in a cultivation farm in Korea. A total of 11 characters of Undaria were measured to determine a reliable morphological character representing its growth and reproduction. Plant weight of Undaria sporophytes increased steadily over the experimental period, but it increased in four different ways. Undaria pinnatifida increased body weight by growth in length and width (October–early December), and by growth in width with the thickening of blade and stipe when sporophytes began to be fertile (December–January). In the middle of January, growth in length and width had almost stopped with the maturation of Undaria sporophytes. Finally, the weight of Undaria increased again by growth in width at the end of February. Present results indicate that Undaria sporophytes increase body weight by growth in length and width at different times, and the relationship between reproduction and vegetative growth is exclusive. Plant weight was positively correlated and fitted well with stipe width and blade width. The blade of Undaria was very thin (ca. 254 μm) and breakable by wave action, but its stipe was strong and relatively thick (ca. 8.7 mm). Furthermore, the fertility of U. pinnatifida was fitted better with stipe width than blade width. Thus, we suggest that the stipe width is the most feasible character with which to estimate the growth and reproduction of U. pinnatifida sporophytes in the cultivation farm. PMID:19396348

  2. Growth, allocation and tissue chemistry of Picea abies seedlings affected by nutrient supply during the second growing season.

    PubMed

    Kaakinen, Seija; Jolkkonen, Annika; Iivonen, Sari; Vapaavuori, Elina

    2004-06-01

    One-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were grown hydroponically in a growth chamber to investigate the effects of low and high nutrient availability (LN; 0.25 mM N and HN; 2.50 mM N) on growth, biomass allocation and chemical composition of needles, stem and roots during the second growing season. Climatic conditions in the growth chamber simulated the mean growing season from May to early October in Flakaliden, northern Sweden. In the latter half of the growing season, biomass allocation changed in response to nutrient availability: increased root growth and decreased shoot growth led to higher root/shoot ratios in LN seedlings than in HN seedlings. At high nutrient availability, total biomass, especially stem biomass, increased, as did total nonstructural carbohydrate and nitrogen contents per seedling. Responses of stem chemistry to nutrient addition differed from those of adult trees of the same provenance. In HN seedlings, concentrations of alpha-cellulose, hemicellulose and lignin decreased in the secondary xylem. Our results illustrate the significance of retranslocation of stored nutrients to support new growth early in the season when root growth and nutrient uptake are still low. We conclude that nutrient availability alters allocation patterns, thereby influencing the success of 2-year-old Norway spruce seedlings at forest planting sites. PMID:15059771

  3. Negative correlation does not imply a tradeoff between growth and reproduction in California oaks

    PubMed Central

    Knops, Johannes M. H.; Koenig, Walter D.; Carmen, William J.

    2007-01-01

    A tradeoff between growth and reproduction, often inferred from an inverse correlation between these two variables, is a fundamental paradigm of life-history evolution. Oak species provide a unique test of this relationship because different species mature acorns either in the year of pollination or in the year after pollination. This difference allows for an interspecific comparison testing whether the apparent tradeoff is causal or the result of confounding factors influencing growth and reproduction independently. Based on 13 years of data on five California oak species, we found significant negative correlations between radial growth and seed production in the three species that produce acorns the same year in which pollination occurs, but not in two species that mature acorns the year after pollination. Rainfall, which correlates positively with radial growth and correlates negatively with acorn production (based on the year of pollination), appears to be driving this pattern. We conclude that the observed negative correlations are not causal, but rather a consequence of growth and reproduction being dependent, in opposite ways, on environmental conditions. Thus, contrary to the current consensus, growth and reproduction in these species are apparently largely independent of each other. In contrast, tradeoffs between current and future reproduction appear to be much more important in the life-history evolution of these long-lived plants. We also conclude that a negative correlation does not necessarily imply a causal mechanism and should not be used as the only evidence supporting a tradeoff. PMID:17940035

  4. Reproduction, larval growth, and reproductive development in African clawed frogs (Xenopus laevis) exposed to atrazine.

    PubMed

    Du Preez, Louis H; Kunene, Nisile; Everson, Gideon J; Carr, James A; Giesy, John P; Gross, Timothy S; Hosmer, Alan J; Kendall, Ronald J; Smith, Ernest E; Solomon, Keith R; Van Der Kraak, Glen J

    2008-03-01

    Reproductive success and development of F2 offspring from F1 adult African clawed frogs (Xenopus laevis) exposed to atrazine throughout larval development and as sexually mature adults was examined. Larval X. laevis were exposed to one of four nominal concentrations of atrazine (0, 1, 10, 25 microg atrazine/l) beginning 96 hr after fertilization and continuing through two years post-metamorphosis. Clutch size and survival of offspring were used as measurement endpoints to gauge reproductive success of the F1 frogs. Larval survivorship and time to metamorphosis were used to gauge developmental success of the F2 offspring from atrazine-exposed frogs. Testes in F1 and F2 frogs were examined for incidence of anomalies, such as testicular ovarian follicles, and sex ratios in F2 offspring were investigated to determine if exposure to atrazine caused trans-generational effects (effects on F2 individuals due to exposure of F1 individuals). There were no effects of any of the studied concentrations of atrazine on clutch size of F1 frogs. There were also no effects on hatching success or time to metamorphosis. Sex ratios did not differ between F2 offspring among treatments. There was no evidence to suggest a transgenerational effect of atrazine on spawning success or reproductive development of X. laevis. This is consistent with the presence of robust populations of X. laevis in areas where they are exposed to atrazine that has been used for several decades for weed control in production of corn. Our observations also are consistent with the results of most other studies of frogs where no effects were found to be associated with exposure to atrazine. Our data do not support the hypothesis that atrazine significantly affects reproductive fitness and development of frogs.

  5. Population level consequences of toxicological influences on individual growth and reproduction in Lumbricus rubellus (Lumbricidae, Oligochaeta).

    PubMed

    Klok, C; de Roos, A M

    1996-03-01

    The effects of increased environmental concentrations of copper on the population dynamics of Lumbricus rubellus are investigated. A size-structured matrix model is used to translate sublethal effects on individual growth and reproduction into their population dynamical consequences. Laboratory data on growth and reproduction under different, sublethal conditions of copper stress are used to parameterize the model. An estimate for the critical threshold concentration of copper (critical in a sense that the population growth rate at this concentration equals zero), obtained from the model analysis, agrees well with observations on field populations of L. rubellus. PMID:8723748

  6. Distributed Generators Allocation in Radial Distribution Systems with Load Growth using Loss Sensitivity Approach

    NASA Astrophysics Data System (ADS)

    Kumar, Ashwani; Vijay Babu, P.; Murty, V. V. S. N.

    2016-07-01

    Rapidly increasing electricity demands and capacity shortage of transmission and distribution facilities are the main driving forces for the growth of distributed generation (DG) integration in power grids. One of the reasons for choosing a DG is its ability to support voltage in a distribution system. Selection of effective DG characteristics and DG parameters is a significant concern of distribution system planners to obtain maximum potential benefits from the DG unit. The objective of the paper is to reduce the power losses and improve the voltage profile of the radial distribution system with optimal allocation of the multiple DG in the system. The main contribution in this paper is (i) combined power loss sensitivity (CPLS) based method for multiple DG locations, (ii) determination of optimal sizes for multiple DG units at unity and lagging power factor, (iii) impact of DG installed at optimal, that is, combined load power factor on the system performance, (iv) impact of load growth on optimal DG planning, (v) Impact of DG integration in distribution systems on voltage stability index, (vi) Economic and technical Impact of DG integration in the distribution systems. The load growth factor has been considered in the study which is essential for planning and expansion of the existing systems. The technical and economic aspects are investigated in terms of improvement in voltage profile, reduction in total power losses, cost of energy loss, cost of power obtained from DG, cost of power intake from the substation, and savings in cost of energy loss. The results are obtained on IEEE 69-bus radial distribution systems and also compared with other existing methods.

  7. The significance of growth in Chironomus tentans sediment toxicity tests: Relationship to reproduction and demographic endpoints

    SciTech Connect

    Sibley, P.K.; Benoit, D.A.; Ankley, G.T.

    1997-02-01

    In the Chironomus tentans 10-d growth test, changes in larval growth relative to sediment contamination are often ascribed ecological relevance by assuming that such changes become manifest at the population level through effects on reproductive output. The objective of this study was to evaluate the relationship between growth and reproduction in C. tentans and to use these data in a demographic model to predict the growth and size of a theoretical population. Growth was manipulated by varying food supply. The test was initiated with 12 newly hatched larvae per replicate and carried through one complete generation. Larval growth and survival were determined at 20 d, and reproduction was monitored daily during emergence. Food supply did not significantly affect survivorship at any life stage; survival of larvae at 20 d, pupae, and adults exceeded 83%, while survival of larvae in the reproduction replicates exceeded 65%. Both larval and adult dry weight declined significantly with a reduction in food supply. Total emergence was reduced at the lowest feeding level only, whereas the rate of emergence declined at food supplies below 0.42 mg/individual per d. Based on the relationship between larval and adult dry weight, a minimum larval tissue mass of between 0.5 and 0.6 mg dry weight/individual appears to be necessary before emergence can take place. The number of eggs/female declined significantly with a decrease in food supply below 0.42 mg/individual per d. Above this level, the addition of more food had no effect on reproductive output. Fecundity (number of daughters/female) and expected number of progeny declined linearly with reduced food supply. Application of the data in a demographic model showed that the growth and predicted size of a population would decline significantly with a decline in larval growth and reproductive output.

  8. Sexual Reproduction in a Simple Growth Population Model

    NASA Astrophysics Data System (ADS)

    Lemos, Carlos Gentil Oro; Santos, Marcio

    2012-05-01

    One of the most important characteristics in the survival of a species is related to the kind of reproduction responsible for the offspring generation. However, only in the last years the role played by sexual reproduction has been investigated. Then, for a better understanding of this kind of process we introduce, in this work, a surface reaction model that describes the role of the sexual reproduction. In our model two different elements of the species, representing male and female, can interact to reproduce a new element. The sex of this new element is chosen with a given probability and in order to take into account the mortality rate we introduce another kind of individual. The value of the spatial density of this element remains constant during the time evolution of the system. The model is studied using Monte Carlo simulations and mean field approximation. Depending on the values of the control parameters of the model, the system can attain two stationary states: In one of them the population survives and in the other it can be extinguished. Besides, accordingly to our results, the phase diagram of the model shows a discontinuous transition between these two states.

  9. Carbon budget for Scots pine trees: effects of size, competition and site fertility on growth allocation and production.

    PubMed

    Vanninen, Petteri; Mäkelä, Annikki

    2005-01-01

    Time series of carbon fluxes in individual Scots pine (Pinus sylvestris L.) trees were constructed based on biomass measurements and information about component-specific turnover and respiration rates. Foliage, branch, stem sapwood, heartwood and bark components of aboveground biomass were measured in 117 trees sampled from 17 stands varying in age, density and site fertility. A subsample of 32 trees was measured for belowground biomass excluding fine roots. Biomass of fine roots was estimated from the results of an earlier study. Statistical models were constructed to predict dry mass (DW) of components from tree height and basal area, and time derivatives of these models were used to estimate biomass increments from height growth and basal area growth. Biomass growth (G) was estimated by adding estimated biomass turnover rates to increments, and gross photosynthetic production (P) was estimated by adding estimated component respiration rates to growth. The method, which predicts the time course of G, P and biomass increment in individual trees as functions of height growth and basal area growth, was applied to eight example trees representing different dominance positions and site fertilities. Estimated G and P of the example trees varied with competition, site fertility and tree height, reaching maximum values of 22 and 43 kg(DW) year(-1), respectively. The site types did not show marked differences in productivity of trees of the same height, although height growth was greater on the fertile site. The G:P ratio decreased with tree height from 65 to 45%. Growth allocation to needles and branches increased with increasing dominance, whereas growth allocation to the stem decreased. Growth allocation to branches decreased and growth allocation to coarse roots increased with increasing tree size. Trees at the poor site allocated 49% more to fine roots than trees at the fertile site. The belowground parts accounted for 25 to 55% of annual G, increasing with tree size

  10. Relative importance of photosynthetic physiology and biomass allocation for tree seedling growth across a broad light gradient.

    PubMed

    Montgomery, Rebecca

    2004-02-01

    Studies of tree seedling physiology and growth under field conditions provide information on the mechanisms underlying inter- and intraspecific differences in growth and survival at a critical period during forest regeneration. I compared photosynthetic physiology, growth and biomass allocation in seedlings of three shade-tolerant tree species, Virola koschynii Warb., Dipteryx panamensis (Pittier) Record & Mell and Brosimum alicastrum Swartz., growing across a light gradient created by a forest-pasture edge (0.5 to 67% diffuse transmittance (%T)). Most growth and physiological traits showed nonlinear responses to light availability, with the greatest changes occurring between 0.5 and 20 %T. Specific leaf area (SLA) and nitrogen per unit leaf mass (N mass) decreased, maximum assimilation per unit leaf area (A area) and area-based leaf N concentration (N area) increased, and maximum assimilation per unit leaf mass (A mass) did not change with increasing irradiance. Plastic responses in SLA were important determinants of leaf N and A area across the gradient. Species differed in magnitude and plasticity of growth; B. alicastrum had the lowest relative growth rates (RGR) and low plasticity. Its final biomass varied only 10-fold across the light gradient. In contrast, the final biomass of D. panamensis and V. koschynii varied by 100- and 50-fold, respectively, and both had higher RGR than B. alicastrum. As light availability increased, all species decreased biomass allocation to leaf tissue (mass and area) and showed a trade-off between allocation to leaf area at a given plant mass (LAR) and net gain in mass per unit leaf area (net assimilation rate, NAR). This trade-off largely reflected declines in SLA with increasing light. Finally, A area was correlated with NAR and both were major determinants of intraspecific variation in RGR. These data indicate the importance of plasticity in photosynthetic physiology and allocation for variation in tree seedling growth among

  11. SuMoToRI, an Ecophysiological Model to Predict Growth and Sulfur Allocation and Partitioning in Oilseed Rape (Brassica napus L.) Until the Onset of Pod Formation.

    PubMed

    Brunel-Muguet, Sophie; Mollier, Alain; Kauffmann, François; Avice, Jean-Christophe; Goudier, Damien; Sénécal, Emmanuelle; Etienne, Philippe

    2015-01-01

    Sulfur (S) nutrition in rapeseed (Brassica napus L.) is a major concern for this high S-demanding crop, especially in the context of soil S oligotrophy. Therefore, predicting plant growth, S plant allocation (between the plant's compartments) and S pool partitioning (repartition of the mobile-S vs. non-mobile-S fractions) until the onset of reproductive phase could help in the diagnosis of S deficiencies during the early stages. For this purpose, a process-based model, SuMoToRI (Sulfur Model Toward Rapeseed Improvement), was developed up to the onset of pod formation. The key features rely on (i) the determination of the S requirements used for growth (structural and metabolic functions) through critical S dilution curves and (ii) the estimation of a mobile pool of S that is regenerated by daily S uptake and remobilization from senescing leaves. This study describes the functioning of the model and presents the model's calibration and evaluation. SuMoToRI was calibrated and evaluated with independent datasets from greenhouse experiments under contrasting S supply conditions. It is run with a small number of parameters with generic values, except in the case of the radiation use efficiency, which was shown to be modulated by S supply. The model gave satisfying predictions of the dynamics of growth, S allocation between compartments and S partitioning, such as the mobile-S fraction in the leaves, which is an indicator of the remobilization potential toward growing sinks. The mechanistic features of SuMoToRI provide a process-based framework that has enabled the description of the S remobilizing process in a species characterized by senescence during the vegetative phase. We believe that this model structure could be useful for modeling S dynamics in other arable crops that have similar senescence-related characteristics. PMID:26635825

  12. SuMoToRI, an Ecophysiological Model to Predict Growth and Sulfur Allocation and Partitioning in Oilseed Rape (Brassica napus L.) Until the Onset of Pod Formation

    PubMed Central

    Brunel-Muguet, Sophie; Mollier, Alain; Kauffmann, François; Avice, Jean-Christophe; Goudier, Damien; Sénécal, Emmanuelle; Etienne, Philippe

    2015-01-01

    Sulfur (S) nutrition in rapeseed (Brassica napus L.) is a major concern for this high S-demanding crop, especially in the context of soil S oligotrophy. Therefore, predicting plant growth, S plant allocation (between the plant’s compartments) and S pool partitioning (repartition of the mobile-S vs. non-mobile-S fractions) until the onset of reproductive phase could help in the diagnosis of S deficiencies during the early stages. For this purpose, a process-based model, SuMoToRI (Sulfur Model Toward Rapeseed Improvement), was developed up to the onset of pod formation. The key features rely on (i) the determination of the S requirements used for growth (structural and metabolic functions) through critical S dilution curves and (ii) the estimation of a mobile pool of S that is regenerated by daily S uptake and remobilization from senescing leaves. This study describes the functioning of the model and presents the model’s calibration and evaluation. SuMoToRI was calibrated and evaluated with independent datasets from greenhouse experiments under contrasting S supply conditions. It is run with a small number of parameters with generic values, except in the case of the radiation use efficiency, which was shown to be modulated by S supply. The model gave satisfying predictions of the dynamics of growth, S allocation between compartments and S partitioning, such as the mobile-S fraction in the leaves, which is an indicator of the remobilization potential toward growing sinks. The mechanistic features of SuMoToRI provide a process-based framework that has enabled the description of the S remobilizing process in a species characterized by senescence during the vegetative phase. We believe that this model structure could be useful for modeling S dynamics in other arable crops that have similar senescence-related characteristics. PMID:26635825

  13. Seedling growth and biomass allocation in relation to leaf habit and shade tolerance among 10 temperate tree species.

    PubMed

    Modrzyński, Jerzy; Chmura, Daniel J; Tjoelker, Mark G

    2015-08-01

    Initial growth of germinated seeds is an important life history stage, critical for establishment and succession in forests. Important questions remain regarding the differences among species in early growth potential arising from shade tolerance. In addition, the role of leaf habit in shaping relationships underlying shade tolerance-related differences in seedling growth remains unresolved. In this study we examined variation in morphological and physiological traits among seedlings of 10 forest tree species of the European temperate zone varying in shade tolerance and leaf habit (broadleaved winter-deciduous species vs needle-leaved conifers) during a 10-week period. Seeds were germinated and grown in a controlled environment simulating an intermediate forest understory light environment to resolve species differences in initial growth and biomass allocation. In the high-resource experimental conditions during the study, seedlings increased biomass allocation to roots at the cost of leaf biomass independent of shade tolerance and leaf habit. Strong correlations between relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA) and leaf mass fraction (LMF) indicate that physiology and biomass allocation were equally important determinants of RGR as plant structure and leaf morphology among these species. Our findings highlight the importance of seed mass- and seed size-related root morphology (specific root length-SRL) for shade tolerance during early ontogeny. Leaf and plant morphology (SLA, LAR) were more successful in explaining variation among species due to leaf habit than shade tolerance. In both broadleaves and conifers, shade-tolerant species had lower SRL and greater allocation of biomass to stems (stem mass fraction). Light-seeded shade-intolerant species with greater SRL had greater RGR in both leaf habit groups. However, the greatest plant mass was accumulated in the group of heavy-seeded shade

  14. Seedling growth and biomass allocation in relation to leaf habit and shade tolerance among 10 temperate tree species.

    PubMed

    Modrzyński, Jerzy; Chmura, Daniel J; Tjoelker, Mark G

    2015-08-01

    Initial growth of germinated seeds is an important life history stage, critical for establishment and succession in forests. Important questions remain regarding the differences among species in early growth potential arising from shade tolerance. In addition, the role of leaf habit in shaping relationships underlying shade tolerance-related differences in seedling growth remains unresolved. In this study we examined variation in morphological and physiological traits among seedlings of 10 forest tree species of the European temperate zone varying in shade tolerance and leaf habit (broadleaved winter-deciduous species vs needle-leaved conifers) during a 10-week period. Seeds were germinated and grown in a controlled environment simulating an intermediate forest understory light environment to resolve species differences in initial growth and biomass allocation. In the high-resource experimental conditions during the study, seedlings increased biomass allocation to roots at the cost of leaf biomass independent of shade tolerance and leaf habit. Strong correlations between relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA) and leaf mass fraction (LMF) indicate that physiology and biomass allocation were equally important determinants of RGR as plant structure and leaf morphology among these species. Our findings highlight the importance of seed mass- and seed size-related root morphology (specific root length-SRL) for shade tolerance during early ontogeny. Leaf and plant morphology (SLA, LAR) were more successful in explaining variation among species due to leaf habit than shade tolerance. In both broadleaves and conifers, shade-tolerant species had lower SRL and greater allocation of biomass to stems (stem mass fraction). Light-seeded shade-intolerant species with greater SRL had greater RGR in both leaf habit groups. However, the greatest plant mass was accumulated in the group of heavy-seeded shade

  15. Simulation of tree-ring widths with a model for primary production, carbon allocation, and growth

    NASA Astrophysics Data System (ADS)

    Li, G.; Harrison, S. P.; Prentice, I. C.; Falster, D.

    2014-12-01

    We present a simple, generic model of annual tree growth, called "T". This model accepts input from a first-principles light-use efficiency model (the "P" model). The P model provides values for gross primary production (GPP) per unit of absorbed photosynthetically active radiation (PAR). Absorbed PAR is estimated from the current leaf area. GPP is allocated to foliage, transport tissue, and fine-root production and respiration in such a way as to satisfy well-understood dimensional and functional relationships. Our approach thereby integrates two modelling approaches separately developed in the global carbon-cycle and forest-science literature. The T model can represent both ontogenetic effects (the impact of ageing) and the effects of environmental variations and trends (climate and CO2) on growth. Driven by local climate records, the model was applied to simulate ring widths during the period 1958-2006 for multiple trees of Pinus koraiensis from the Changbai Mountains in northeastern China. Each tree was initialised at its actual diameter at the time when local climate records started. The model produces realistic simulations of the interannual variability in ring width for different age cohorts (young, mature, and old). Both the simulations and observations show a significant positive response of tree-ring width to growing-season total photosynthetically active radiation (PAR0) and the ratio of actual to potential evapotranspiration (α), and a significant negative response to mean annual temperature (MAT). The slopes of the simulated and observed relationships with PAR0 and α are similar; the negative response to MAT is underestimated by the model. Comparison of simulations with fixed and changing atmospheric CO2 concentration shows that CO2 fertilisation over the past 50 years is too small to be distinguished in the ring-width data, given ontogenetic trends and interannual variability in climate.

  16. Simulating the effects of fluctuating dissolved oxygen on growth, reproduction, and survival of fish and shrimp.

    PubMed

    Miller Neilan, Rachael; Rose, Kenneth

    2014-02-21

    Individuals are commonly exposed to fluctuating levels of stressors, while most laboratory experiments focus on constant exposures. We develop and test a mathematical model for predicting the effects of low dissolved oxygen (hypoxia) on growth, reproduction, and survival using laboratory experiments on fish and shrimp. The exposure-effects model simulates the hourly reductions in growth and survival, and the reduction in reproduction (fecundity) at times of spawning, of an individual as it is exposed to constant or hourly fluctuating dissolved oxygen (DO) concentrations. The model was applied to seven experiments involving fish and shrimp that included constant and fluctuating DO exposures, with constant exposures used for parameter estimation and the model then used to simulate the growth, reproduction, and survival in the fluctuating treatments. Cumulative effects on growth, reproduction, and survival were predicted well by the model, but the model did not replay the observed episodic low survival days. Further investigation should involve the role of acclimation, possible inclusion of repair effects in reproduction and survival, and the sensitivity of model predictions to the shape of the immediate effects function. Additional testing of the model with other taxa, different patterns of fluctuating exposures, and different stressors is needed to determine the model's generality and robustness.

  17. Evaluation of Moringa oleifera as a dietary supplement on growth and reproductive performance in zebrafish

    PubMed Central

    Paul, Latoya T.; Fowler, Lauren A.; Barry, Robert J.; Watts, Stephen A.

    2016-01-01

    The leaves of the Moringa oleifera (Moringa) tree contain a significant source of protein, vitamins and minerals, and are considered as an important dietary supplement in countries where chronic malnourishment is linked to poor fetal development. We evaluated the effectiveness of the Moringa leaf as a supplemental replacement for vitamins, minerals, and protein in a formulated zebrafish diet and the impact that it may have on growth and reproductive outcome. Diets included a formulated control (FC) containing an array of vitamins and mineral supplements (pre-mixes), dried ground Moringa only (M), formulated control minus vitamin and mineral pre-mixes (Fvm), and formulated control minus vitamin and mineral pre-mixes and supplemented with Moringa (FM). Juvenile zebrafish were fed experimental diets ad libitum. After a 12 week feeding period, each treatment group was evaluated based on growth and reproductive performance. The M treatment showed the least growth performance (length and weight gain) and no reproductive success (no egg production). Although small, M fish appeared otherwise healthy, with survivorship at ca. 70%, suggesting, Moringa can serve as a single ingredient source for a short period of time. FC showed the highest growth performance, and had the highest reproductive success. Growth performance and reproduction in the Fvm diet was greatly reduced. However, inclusion of Moringa (FM) promoted significant, but not total, recovery of growth and reproductive metrics. These data suggest that Moringa leaves can serve as an acceptable supplement for macro and micronutrients in the diet and could, in part, reduce problems associated with nutrient deficiencies. PMID:27570785

  18. Complex Genetic Effects on Early Vegetative Development Shape Resource Allocation Differences Between Arabidopsis lyrata Populations

    PubMed Central

    Remington, David L.; Leinonen, Päivi H.; Leppälä, Johanna; Savolainen, Outi

    2013-01-01

    Costs of reproduction due to resource allocation trade-offs have long been recognized as key forces in life history evolution, but little is known about their functional or genetic basis. Arabidopsis lyrata, a perennial relative of the annual model plant A. thaliana with a wide climatic distribution, has populations that are strongly diverged in resource allocation. In this study, we evaluated the genetic and functional basis for variation in resource allocation in a reciprocal transplant experiment, using four A. lyrata populations and F2 progeny from a cross between North Carolina (NC) and Norway parents, which had the most divergent resource allocation patterns. Local alleles at quantitative trait loci (QTL) at a North Carolina field site increased reproductive output while reducing vegetative growth. These QTL had little overlap with flowering date QTL. Structural equation models incorporating QTL genotypes and traits indicated that resource allocation differences result primarily from QTL effects on early vegetative growth patterns, with cascading effects on later vegetative and reproductive development. At a Norway field site, North Carolina alleles at some of the same QTL regions reduced survival and reproductive output components, but these effects were not associated with resource allocation trade-offs in the Norway environment. Our results indicate that resource allocation in perennial plants may involve important adaptive mechanisms largely independent of flowering time. Moreover, the contributions of resource allocation QTL to local adaptation appear to result from their effects on developmental timing and its interaction with environmental constraints, and not from simple models of reproductive costs. PMID:23979581

  19. Physical stress modifies top-down and bottom-up forcing on plant growth and reproduction in a coastal ecosystem.

    PubMed

    Daleo, Pedro; Alberti, Juan; Bruschetti, Carlos Martin; Pascual, Jesos; Iribarne, Oscar; Silliman, Brian R

    2015-08-01

    Bottom-up and top-down effects act together to exert strong control over plant growth and reproduction, but how physical stress modifies those interactive forces remains unclear. Even though empirical evidence is scarce, theory predicts that the importance of both top-down- and bottom-up forces may decrease as physical stress increases. Here, we experimentally evaluate in the field the separate and interactive effect of salinity, nutrient availability, and crab herbivory on plant above- and belowground biomass, as well as on sexual and clonal reproduction in the salt marsh plant Spartina densiflora. Results show that the outcome of the interaction between nutrient availability and herbivory is highly context dependent, not only varying with the abiotic context (i.e., with or without increased salinity stress), but also with the dependent variable considered. Contrary to theoretical predictions, our results show that, consistently across different measured variables, salinity stress did not cancel bottom-up (i.e., nutrients) or top-down (i.e., consumers) control, but has additive effects. Our results support emerging theory by highlighting that, under many conditions, physical stress can act additively with, or even stimulate, consumer control, especially in cases where the physical stress is only experienced by basal levels of the trophic chain. Abiotic stress, as well as bottom-up and top-down factors, can affect salt marsh structure and function not only by affecting biomass production but also by having other indirect effects, such as changing patterns in plant biomass allocation and reproduction. PMID:26405740

  20. Biomass Allocation of Stoloniferous and Rhizomatous Plant in Response to Resource Availability: A Phylogenetic Meta-Analysis.

    PubMed

    Xie, Xiu-Fang; Hu, Yu-Kun; Pan, Xu; Liu, Feng-Hong; Song, Yao-Bin; Dong, Ming

    2016-01-01

    Resource allocation to different functions is central in life-history theory. Plasticity of functional traits allows clonal plants to regulate their resource allocation to meet changing environments. In this study, biomass allocation traits of clonal plants were categorized into absolute biomass for vegetative growth vs. for reproduction, and their relative ratios based on a data set including 115 species and derived from 139 published literatures. We examined general pattern of biomass allocation of clonal plants in response to availabilities of resource (e.g., light, nutrients, and water) using phylogenetic meta-analysis. We also tested whether the pattern differed among clonal organ types (stolon vs. rhizome). Overall, we found that stoloniferous plants were more sensitive to light intensity than rhizomatous plants, preferentially allocating biomass to vegetative growth, aboveground part and clonal reproduction under shaded conditions. Under nutrient- and water-poor condition, rhizomatous plants were constrained more by ontogeny than by resource availability, preferentially allocating biomass to belowground part. Biomass allocation between belowground and aboveground part of clonal plants generally supported the optimal allocation theory. No general pattern of trade-off was found between growth and reproduction, and neither between sexual and clonal reproduction. Using phylogenetic meta-analysis can avoid possible confounding effects of phylogeny on the results. Our results shown the optimal allocation theory explained a general trend, which the clonal plants are able to plastically regulate their biomass allocation, to cope with changing resource availability, at least in stoloniferous and rhizomatous plants. PMID:27200071

  1. Biomass Allocation of Stoloniferous and Rhizomatous Plant in Response to Resource Availability: A Phylogenetic Meta-Analysis.

    PubMed

    Xie, Xiu-Fang; Hu, Yu-Kun; Pan, Xu; Liu, Feng-Hong; Song, Yao-Bin; Dong, Ming

    2016-01-01

    Resource allocation to different functions is central in life-history theory. Plasticity of functional traits allows clonal plants to regulate their resource allocation to meet changing environments. In this study, biomass allocation traits of clonal plants were categorized into absolute biomass for vegetative growth vs. for reproduction, and their relative ratios based on a data set including 115 species and derived from 139 published literatures. We examined general pattern of biomass allocation of clonal plants in response to availabilities of resource (e.g., light, nutrients, and water) using phylogenetic meta-analysis. We also tested whether the pattern differed among clonal organ types (stolon vs. rhizome). Overall, we found that stoloniferous plants were more sensitive to light intensity than rhizomatous plants, preferentially allocating biomass to vegetative growth, aboveground part and clonal reproduction under shaded conditions. Under nutrient- and water-poor condition, rhizomatous plants were constrained more by ontogeny than by resource availability, preferentially allocating biomass to belowground part. Biomass allocation between belowground and aboveground part of clonal plants generally supported the optimal allocation theory. No general pattern of trade-off was found between growth and reproduction, and neither between sexual and clonal reproduction. Using phylogenetic meta-analysis can avoid possible confounding effects of phylogeny on the results. Our results shown the optimal allocation theory explained a general trend, which the clonal plants are able to plastically regulate their biomass allocation, to cope with changing resource availability, at least in stoloniferous and rhizomatous plants.

  2. Biomass Allocation of Stoloniferous and Rhizomatous Plant in Response to Resource Availability: A Phylogenetic Meta-Analysis

    PubMed Central

    Xie, Xiu-Fang; Hu, Yu-Kun; Pan, Xu; Liu, Feng-Hong; Song, Yao-Bin; Dong, Ming

    2016-01-01

    Resource allocation to different functions is central in life-history theory. Plasticity of functional traits allows clonal plants to regulate their resource allocation to meet changing environments. In this study, biomass allocation traits of clonal plants were categorized into absolute biomass for vegetative growth vs. for reproduction, and their relative ratios based on a data set including 115 species and derived from 139 published literatures. We examined general pattern of biomass allocation of clonal plants in response to availabilities of resource (e.g., light, nutrients, and water) using phylogenetic meta-analysis. We also tested whether the pattern differed among clonal organ types (stolon vs. rhizome). Overall, we found that stoloniferous plants were more sensitive to light intensity than rhizomatous plants, preferentially allocating biomass to vegetative growth, aboveground part and clonal reproduction under shaded conditions. Under nutrient- and water-poor condition, rhizomatous plants were constrained more by ontogeny than by resource availability, preferentially allocating biomass to belowground part. Biomass allocation between belowground and aboveground part of clonal plants generally supported the optimal allocation theory. No general pattern of trade-off was found between growth and reproduction, and neither between sexual and clonal reproduction. Using phylogenetic meta-analysis can avoid possible confounding effects of phylogeny on the results. Our results shown the optimal allocation theory explained a general trend, which the clonal plants are able to plastically regulate their biomass allocation, to cope with changing resource availability, at least in stoloniferous and rhizomatous plants. PMID:27200071

  3. THE INFLUENCE OF MODEL TIME STEP ON THE RELATIVE SENSITIVITY OF POPULATION GROWTH TO SURVIVAL, GROWTH AND REPRODUCTION

    EPA Science Inventory

    Matrix population models are often used to extrapolate from life stage-specific stressor effects on survival and reproduction to population-level effects. Demographic elasticity analysis of a matrix model allows an evaluation of the relative sensitivity of population growth rate ...

  4. Interaction of diet and photoperiod on growth and reproduction in male golden hamsters.

    PubMed

    Johnson, L B; Hoffman, R A

    1985-01-01

    Two basic diets (commercial rodent pellets or seeds) with or without supplements of carbohydrate were tested for growth and development, and effects on organ weights and serum calcium in male golden hamsters. The additional influence of photoperiod was measured. The data suggest that a seed diet alone is not adequate for growth. Addition of seeds and/or carbohydrate to the pellet diet increases growth rates substantially compared to the pellet diet alone. There are significant interaction effects on reproduction between diet and photoperiod indicating that diet can modify responses to short photic input. While reproduction remains essentially normal in seed-fed animals in long photoperiods, the rate of reproductive involution in short photoperiods is greatly enhanced. Added carbohydrate appears to offer some protection against the adverse effect of short photoperiods on reproduction. Even though calcium supplements to the diet increase serum calcium levels toward normal, growth rates are not improved. Addition of Tenebrio (grain beetle) larvae to the seed diet induces growth rates comparable to those of control animals, yet serum calcium levels remain significantly lower.

  5. Impact of tail-nipping on mortality, growth and reproduction of Arenicola marina

    NASA Astrophysics Data System (ADS)

    Bergman, Magda J. N.; Van Der Veer, Henk W.; Karczmarski, Leszek

    The impact of predation by amputation of regenerating body parts (tail tips) of the lugworm Arenicola marina on species mortality, growth and reproduction has been studied under laboratory conditions by the artificial removal of tail tips at different frequencies. The loss of body weight by amputation was not compensated for by an increased growth. Within a wide range of amputation frequencies, total growth (body growth + amount of tail tip amputated) and reproduction of the lugworm were not affected. Also, both egg development and amount of energy stored in reproduction remained the same. Only at the highest frequency of amputation (once a week) did total growth decrease in the course of time, resulting even in a loss of body weight. The amount of energy stored in reproduction was also significantly less at the highest rate of amputation. Lugworms appeared to be unable to sustain this high level of amputation and the anaerobic sediment conditions in the cuvettes suggest a reduced pumping activity and food intake. Mortality in this group was also higher than in the other groups. The consequences of tail-nipping by flatfish for A. marina in the field situation are discussed.

  6. Emerging role of PLAG1 as a regulator of growth and reproduction.

    PubMed

    Juma, Almas R; Damdimopoulou, Pauliina E; Grommen, Sylvia V H; Van de Ven, Wim J M; De Groef, Bert

    2016-02-01

    Pleomorphic adenoma gene 1 (PLAG1) belongs to the PLAG family of zinc finger transcription factors along with PLAG-like 1 and PLAG-like 2. The PLAG1 gene is best known as an oncogene associated with certain types of cancer, most notably pleomorphic adenomas of the salivary gland. While the mechanisms of PLAG1-induced tumorigenesis are reasonably well understood, the role of PLAG1 in normal physiology is less clear. It is known that PLAG1 is involved in cell proliferation by directly regulating a wide array of target genes, including a number of growth factors such as insulin-like growth factor 2. This is likely to be a central mode of action for PLAG1 both in embryonic development and in cancer. The phenotype of Plag1 knockout mice suggests an important role for PLAG1 also in postnatal growth and reproduction, as PLAG1 deficiency causes growth retardation and reduced fertility. A role for PLAG1 in growth and reproduction is further corroborated by genome-wide association studies in humans and domestic animals in which polymorphisms in the PLAG1 genomic region are associated with body growth and reproductive traits. Here we review the current evidence for PLAG1 as a regulator of growth and fertility and discuss possible endocrine mechanisms involved. PMID:26577933

  7. Emerging role of PLAG1 as a regulator of growth and reproduction.

    PubMed

    Juma, Almas R; Damdimopoulou, Pauliina E; Grommen, Sylvia V H; Van de Ven, Wim J M; De Groef, Bert

    2016-02-01

    Pleomorphic adenoma gene 1 (PLAG1) belongs to the PLAG family of zinc finger transcription factors along with PLAG-like 1 and PLAG-like 2. The PLAG1 gene is best known as an oncogene associated with certain types of cancer, most notably pleomorphic adenomas of the salivary gland. While the mechanisms of PLAG1-induced tumorigenesis are reasonably well understood, the role of PLAG1 in normal physiology is less clear. It is known that PLAG1 is involved in cell proliferation by directly regulating a wide array of target genes, including a number of growth factors such as insulin-like growth factor 2. This is likely to be a central mode of action for PLAG1 both in embryonic development and in cancer. The phenotype of Plag1 knockout mice suggests an important role for PLAG1 also in postnatal growth and reproduction, as PLAG1 deficiency causes growth retardation and reduced fertility. A role for PLAG1 in growth and reproduction is further corroborated by genome-wide association studies in humans and domestic animals in which polymorphisms in the PLAG1 genomic region are associated with body growth and reproductive traits. Here we review the current evidence for PLAG1 as a regulator of growth and fertility and discuss possible endocrine mechanisms involved.

  8. Larval growth rate and sex determine resource allocation and stress responsiveness across life stages in juvenile frogs.

    PubMed

    Warne, Robin W; Crespi, Erica J

    2015-03-01

    The extent to which interactions between environmental stressors and phenotypic variation during larval life stages impose carry-over effects on adult phenotypes in wildlife are not clear. Using semi-natural mesocosms, we examined how chronically low food availability and size-specific phenotypes in larval amphibians interact and carry over to influence frog growth, resource allocation, endocrine activity and survival. We tagged three cohorts of larvae that differed in body size and developmental stage at 3 weeks after hatching, and tracked them through 10 weeks after metamorphosis in high and low food conditions. We found that growth and development rates during the early tadpole stage not only affected metamorphic rates, but also shaped resource allocation and stress responsiveness in frogs: the slowest growing larvae from low-food mesocosms exhibited a suppressed glucocorticoid response to a handling stressor; reduced growth rate and fat storage as frogs. We also show for the first time that larval developmental trajectories varied with sex, where females developed faster than males especially in food-restricted conditions. Last, while larval food restriction profoundly affected body size in larvae and frogs, time to metamorphosis was highly constrained, which suggests that the physiology and development of this ephemeral pond-breeding amphibian is adapted for rapid metamorphosis despite large potential variation in nutrient availability. Taken together, these results suggest that larval phenotypic variation significantly influences multiple dimensions of post-metamorphic physiology and resource allocation, which likely affect overall performance.

  9. Leaf dynamics in growth and reproduction of Xanthium canadense as influenced by stand density

    PubMed Central

    Ogawa, Takahiro; Oikawa, Shimpei; Hirose, Tadaki

    2015-01-01

    Background and Aims Leaf longevity is controlled by the light gradient in the canopy and also by the nitrogen (N) sink strength in the plant. Stand density may influence leaf dynamics through its effects on light gradient and on plant growth and reproduction. This study tests the hypothesis that the control by the light gradient is manifested more in the vegetative period, whereas the opposite is true when the plant becomes reproductive and develops a strong N sink. Methods Stands of Xanthium canadense were established at two densities. Emergence, growth and death of every leaf on the main stem and branches, and plant growth and N uptake were determined from germination to full senescence. Mean residence time and dry mass productivity were calculated per leaf number, leaf area, leaf mass and leaf N (collectively termed ‘leaf variables’) in order to analyse leaf dynamics and its effect on plant growth. Key Results Branching and reproductive activities were higher at low than at high density. Overall there was no significant difference in mean residence time of leaf variables between the two stands. However, early leaf cohorts on the main stem had a longer retention time at low density, whereas later cohorts had a longer retention time at high density. Branch leaves emerged earlier and tended to live longer at low than at high density. Leaf efficiencies, defined as carbon export per unit investment of leaf variables, were higher at low density in all leaf variables except for leaf number. Conclusions In the vegetative phase of plant growth, the light gradient strongly controls leaf longevity, whereas later the effects of branching and reproductive activities become stronger and over-rule the effect of light environment. As leaf N supports photosynthesis and also works as an N source for plant development, N use is pivotal in linking leaf dynamics with plant growth and reproduction. PMID:26248476

  10. Sudden cold temperature delays plant carbon transport and shifts allocation from growth to respiratory demand

    NASA Astrophysics Data System (ADS)

    Barthel, M.; Cieraad, E.; Zakharova, A.; Hunt, J. E.

    2014-03-01

    Since substrates for respiration are supplied mainly by recent photo-assimilates, there is a strong but time-lagged link between short-term above- and belowground carbon (C) cycling. However, regulation of this coupling by environmental variables is poorly understood. Whereas recent studies focussed on the effect of drought and shading on the link between above- and belowground short-term C cycling, the effect of temperature remains unclear. We used a 13CO2 pulse-chase labelling experiment to investigate the effect of a sudden temperature change from 25 to 10 °C on the short-term coupling between assimilatory C uptake and respiratory loss. The study was done in the laboratory using two-month-old perennial rye-grass plants (Lolium perenne L.). After label application, the δ13C signal of respired shoot and root samples was analysed at regular time intervals using laser spectroscopy. In addition, δ13C was analysed in bulk root and shoot samples. Cold temperature (10 °C) reduced the short-term coupling between shoot and roots by delaying belowground transfer of recent assimilates and its subsequent respiratory use, as indicated by the δ13C signal of root respiration (δ13CRR). That is, the time lag from the actual shoot labelling to the first appearance of the label in 13CRR was about 1.5 times longer under cold temperature. Moreover, analysis of bulk shoot and root material revealed that plants at cold temperature invest relatively more carbon into respiration compared to growth or storage. While the whole plant C turnover increased under cold temperature, the turnover time of the labile C pool decreased, probably because less 13C is used for growth and/or storage. That is, (almost) all recent C remained in the labile pool serving respiration under these conditions. Overall, our results highlight the importance of temperature as a driver of C transport and relative C allocation within the plant-soil system.

  11. The effect of positive air ions on reproduction and growth in laboratory rats

    NASA Astrophysics Data System (ADS)

    Hinsull, S. M.; Head, E. L.

    1986-03-01

    The aim of the present investigation was to determine the growth rates, reproductive success and early mortality of laboratory rats maintained at 10,000 positive ions/ml over two generations. These findings were compared with those from animals maintained at ambient ion levels. The present work indicates that positive ions do not have any adverse effects on the reproductive capabilities or the growth of laboratory rats. In contrast it is shown that exposure to elevated levels of positive ions promotes overall growth, particularly in male rats. This action of positive ions increases with each successive generation exposed to the ions. It is suggested that the growth promoting effect of positive ions may be mediated via some modulation of the endocrine system.

  12. Production, reproduction, health, and growth traits in backcross holstein x jersey cows and their holstein contemporaries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 648 purebred Holstein and 319 backcross Holstein × Jersey dairy cattle were compared for production, reproduction, health, linear type, and growth traits. Animals were born between 2003 and 2009 and were housed in the University of Wisconsin–Madison Integrated Dairy Facility. All animals ...

  13. Differences between wheat genotypes in damage from freezing temperatures during reproductive growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter cereal crops in the reproductive stage of growth are considerably more susceptible to freezing temperatures than they are during their vegetative stage during the fall. While damage resulting from spring-freeze events has been documented, information on genotypic differences in tolerance to ...

  14. Characterization of reproduction and growth of American robins at the Fernald Environmental Management Project, 1991

    SciTech Connect

    Osborne, D.R.; Ambrose, D.M.; Simpson, J.C.

    1992-11-01

    As part of a Biological and Ecological Site Characterization of the Fernald Environmental Management Project (FEMP), suppressed growth in onsite American robin nestlings was discovered in 1987 and in 1990. However, the causal factors relating to suppressed growth were not investigated. This study was initiated to determine if growth suppression still existed, and if so, the possible relationship of FEMP land management practices and soil contaminants through food chains to growth and reproductive fitness. This study was expanded to include five offsite sampling sites, as well as analyses of soils and earthworms for uranium, pesticides/herbicides, and heavy metals.

  15. Growth and reproductive performance by different feed types in fresh water angelfish (Pterophyllum scalare Schultze, 1823).

    PubMed

    Kasiri, Milad; Farahi, Amin; Sudagar, Mohammad

    2012-01-01

    It is well established that reproduction is sensitive to the state of energy reserves, and that there is a balance between energy homeostasis and fertility. In this view, this study examined the effects of different diets on growth and reproductive performance of fresh water angelfish. Twenty four pairs of angelfish (weighing 3.58 ± 0.24 g) were fed with four types of diets including live earth worm (LEW), dried Tubifex (DT), dried Gammarus (DG) and prepared granulated feed (PGF), twice a day for 90 days. Reproductive parameters were measured between days 60 and 90. The significant increase in the gonadosomatic index (GSI), fecundity and hatchability brought about by the LEW were demonstrated by the higher number of spawned eggs and hatched larvae. The best growth observed significantly in PGF, and length of larvae was enhanced in this group, consequently. The numbers of dead and deformed fry were lower in the fish fed with PGF and LEW, but there was no significant difference among experimental groups. This study showed that breeders benefit from inclusion of prepared granulated feed and living earth worm during their growth and reproductive stages, and simultaneous using of them for achieving better results is suggested.

  16. Reproduction and growth in American robins at the Feed Materials Production Center

    SciTech Connect

    Osborne, D.R.; Jones, F.A. . Dept. of Zoology)

    1991-01-01

    Birds have been useful in environmental monitoring within forest ecosystems and at a variety of industrial sites. Growth analyses have been shown to be a sensitive measure of environmental stress in gulls, eagles, and in passerine birds. As part of an intensive year-long baseline ecological study investigations were initiated in late spring 1987 in order to characterize growth and reproductive success in Mourning Doves (Zenaida macroura) and American Robins (Turdus migratorius) at the Feed Materials Production Center (FMPC). The current study was initiated in order to determine whether the pattern of suppressed growth and reproduction in FMPC birds still existed onsite. We selected only American robins (Turdus migratorius) for study because they appeared the most severely affected in 1987. 44 refs., 3 figs., 3 tabs.

  17. Potassium enrichment stimulates the growth and reproduction of a clone of Daphnia dentifera.

    PubMed

    Civitello, David J; Hite, Jessica L; Hall, Spencer R

    2014-07-01

    Nutrient limitation commonly constrains organisms in natural ecosystems. Typically, ecologists focus on limitation by N and P. However, other nutrients can limit growth or reproduction. Here we focus on K limitation of invertebrate consumers (Daphnia dentifera) and phytoplankton in freshwater lakes. All organisms require K for several metabolic processes. In freshwater, K could limit growth because low external concentrations can increase the energetic costs of accumulating K. Furthermore, in a study linking K to disease, we previously found that K enrichment of water from one low-K lake stimulated the growth and reproduction of Daphnia. Here we test whether K could limit the production of Daphnia and phytoplankton across lakes and years. We repeated a life table experiment using water collected from a low-K lake during a different year. K again stimulated Daphnia reproduction. We also enriched water from 12 lakes with K or P and measured short-term growth of Daphnia and the resident algal community. Both nutrients increased Daphnia growth in five lakes. However, only P enhanced algal production. P stimulation of Daphnia positively correlated with algal quantity and the ratio of C to P in seston. However, K stimulation of Daphnia was not correlated with these factors or the background concentration of K. Thus, this study shows repeatable K-limited animal physiology in nature. Further, we can exclude the hypothesis that K stimulates Daphnia indirectly by enhancing algal production. These patterns call for future physiological studies to uncover the mechanistic basis of K limitation in natural systems.

  18. New horizons at the caudal embryos; coordinated urogenital/reproductive organ formation by growth factor signaling

    PubMed Central

    Suzuki, Kentaro; Economides, Aris; Yanagita, Motoko; Graf, Daniel; Yamada, Gen

    2009-01-01

    Summary The cloaca/urogenital sinus and its adjacent region differentiate into the urogenital/reproductive organs. Caudal regression syndrome (CRS; including Mermaid syndrome), a type of severe cloacal malformation displays hindlimb fusion and urogenital organ defects, thus suggesting that such defects are caused by several morphogenetic alterations during early development. The attenuation of Bone Morphogenetic Protein (Bmp) signaling at the posterior primitive streak of embryos leads to the caudal dysmorphogenesis including the cloaca and fusion of both hindlimbs. Genetic tissue lineage studies indicate the presence of coordinated organogenesis. Hedgehog (HH)-responding cells derived from peri-cloacal mesenchyme (PCM) contribute to the urogenital/reproductive organs. These findings indicate the existence o f developmental programs for the coordinated organogenesis of urogenital/reproductive tissues based on growth factor function and crosstalk. PMID:19765973

  19. Toxicant-disease-environment interactions associated with suppression of immune system, growth, and reproduction. [PCB

    SciTech Connect

    Porter, W.P.; Hinsdill, R.; Fairbrother, A.; Olson, L.J.; Jaeger, J.; Yuill, T.; Bisgaard, S.; Hunter, W.G.; Nolan, K.

    1984-06-01

    The effects of marginal malnourishment, infections, and environmental chemicals on growth and reproductive success in Swiss-Webster white mice and wild deer mice were studied with fractional factorial designs. Interaction effects were discovered. For example, malnourished mice were more sensitive to virus exposure and environmental chemicals (a plant growth regulator or polychlorinated biphenyls). Since several commercial plant growth regulators also appear to suppress the immune system, these results cast doubt on the adequacy of current toxicity testing procedures in which factors are studied individually and not in combination.

  20. Human Disturbance Influences Reproductive Success and Growth Rate in California Sea Lions (Zalophus californianus)

    PubMed Central

    French, Susannah S.; González-Suárez, Manuela; Young, Julie K.; Durham, Susan; Gerber, Leah R.

    2011-01-01

    The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations. PMID:21436887

  1. Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus).

    PubMed

    French, Susannah S; González-Suárez, Manuela; Young, Julie K; Durham, Susan; Gerber, Leah R

    2011-03-16

    The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations.

  2. Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus).

    PubMed

    French, Susannah S; González-Suárez, Manuela; Young, Julie K; Durham, Susan; Gerber, Leah R

    2011-01-01

    The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations. PMID:21436887

  3. Differential Growth of the Reproductive Organs during the Peripubertal Period in Male Rats.

    PubMed

    Han, Seung Hee; Lee, Sung-Ho

    2013-12-01

    In mammals, puberty is a process of acquiring reproductive competence, triggering by activation of hypothalamic kisspeptin (KiSS)-gonadotropin releasing hormone (GnRH) neuronal circuit. During peripubertal period, not only the external genitalia but the internal reproductive organs have to be matured in response to the hormonal signals from hypothalamic-pituitary-gonadal (H-P-G) axis. In the present study, we evaluated the maturation of male rat accessory sex organs during the peripubertal period using tissue weight measurement, histological analysis and RT-PCR assay. Male rats were sacrificed at 25, 30, 35, 40, 45, 50, and 70 postnatal days (PND). The rat accessory sex organs exhibited differential growth patterns compared to those of non-reproductive organs. The growth rate of the accessory sex organs were much higher than the those of non-reproductive organs. Also, the growth spurts occurred differentially even among the accessory sex organs; the order of prepubertal organ growth spurts is testis = epididymis > seminal vesicle = prostate. Histological study revealed that the presence of sperms in seminiferous tubules and epididymal ducts at day 50, indicating the puberty onset. The number of duct and the volume of duct in epididymis and prostate were inversely correlated during the experimental period. Our RT-PCR revealed that the levels of hypothalamic GnRH transcript were increased significantly on PND 40, suggesting the activation of hypothalamic GnRH pulse-generator before puberty onset. Studies on the peripubertal male accessory sex organs will provide useful references on the growth regulation mechanism which is differentially regulated during the period in andevrepogen-sensitive organs. The detailed references will render easier development of endocrine disruption assay.

  4. Growth, reproductive productivity and longevity of mice fed polyunsaturated ruminant-derived foodstuffs.

    PubMed

    Fogerty, A C; Pennycuik, P R; Ferris, M C; Baxter, R I; Johnson, A R

    1979-02-01

    The effects on the well-being of mice of feeding linoleic acid-enriched foodstuffs derived from ruminants receiving protected polyunsaturated oil were determined. Growth, reproductive productivity and longevity were compared in mice fed freeze-dried human diets containing either these products or the corresponding conventional ruminant-derived foods. A laboratory mouse pellet diet was used as a standard for the comparison. Growth rates and life spans were found to be similar in all three groups. Although the reproductive productivity of the mice on the polyunsaturated diet was never significantly different from that of mice on the conventional human diet, productivities of both groups on human diets were usually significantly below those of mice eating pellets. By the third generation of the second reproduction study, productivities of both these groups of mice had returned to the same level as those of mice eating pellets. Possible reasons for the depression in reproductive productivity in mice on the human diets are discussed. It was concluded that the polyunsaturated human diet neither impaired nor improved the lives of the animals eating the diet relative to the lives of animals eating the conventional human diet.

  5. Why Cells Grow and Divide? General Growth Mechanism and How it Defines Cells’ Growth, Reproduction and Metabolic Properties

    NASA Astrophysics Data System (ADS)

    Shestopaloff, Yuri K.

    2015-02-01

    We consider a general growth mechanism, which acts at cellular level and above (organs, systems and whole organisms). Using its mathematical representation, the growth equation, we study the growth and division mechanisms of amoeba and fission yeast Schizosaccharomyces pombe. We show how this mechanism, together with biomolecular machinery, governs growth and reproduction of cells, and these organisms in particular. This mechanism provides revealing answers to fundamental questions of biology, like why cells grow and divide, why and when cells’ growth stops. It also sheds light on questions like why and how life originated and developed. Solving the growth equation, we obtain analytical expression for the growth curve of fission yeast as a function of geometrical characteristics and nutrient influxes for RNA and protein synthesis, and compare the computed growth curves with 85 experiments. Statistical evaluation shows that these growth curves correspond to experimental data significantly better than all previous approximations. Also, using the general growth mechanism, we show how metabolic characteristics of cells, their size and evolutionary traits relate, considering fission yeast. In particular, we found that fission yeast S. pombe consumes about 16-18 times more nutrients for maintenance needs than for biomass synthesis.

  6. Reproduction, growth, and tissue residues of deer fed dieldrin

    USGS Publications Warehouse

    Murphy, D.A.; Korschgen, L.J.

    1970-01-01

    Feeding tests were conducted from January, 1966, to January, 1969, to ascertain the effects of daily ingestions of sublethal amounts of dieldrin on white-tailed deer (Odocoileus virginianus). Groups of deer on 0 ppm dieldrin (controls), 5 ppm, and 25 ppm dieldrin were maintained at these respective levels, as were their progeny. Treated food was readily accepted. Dieldrin intoxication was not observed, and 9 of 10 animals of each group survived 3 years of treatment. No differences in conception or in utero mortality were found between groups. Fawns from dieldrin-fed does were smaller at birth and greater post-partum mortality occurred. Fertility of male progeny was not affected. Growth was slower and remained reduced in dieldrin-treated females which were immature when the study began. Hematologic values and serum protein concentrations were not significantly (P > 0.05) related to treatment. Liver/body weight ratios were significantly (P < 0.05) larger for the 25-ppm-dieldrin group. Pituitary glands were smaller and thyroids were larger in dieldrin-fed deer. Weight gains of fawns were significantly (P < 0.05) reduced 2 of 3 years in dieldrin-treated groups. Placental transfer of dieldrin occurred. Whole milk from does fed 25 ppm dieldrin contained residues of 17 ppm. Residue levels in brain, liver, and thigh muscle tissues showed no evidence of increasing with length of treatment, but showed definite relationships to levels of dieldrin in daily diets. Nursing fawns had higher residues in brain tissues than did older deer on 5 ppm a d 25 ppm dieldrin. Highest brain residues (12.60 and 12.10 ppm, wet weight) occurred in fawns only a few days of age at death. Equilibrium between ingestion and storage or excretion of dieldrin occurred prior to 200 days and continued until nearly 1,100 days. There was no evidence of a sharp decline in residues after a long period of continued dosage. Daily ingestion of 100 and 200 ppm of dieldrin proved fatal to yearling male deer at 27

  7. Allocation of new growth between shoot, root and mycorrhiza in relation to carbon, nitrogen and phosphate supply: teleonomy with maximum growth rate.

    PubMed

    Thornley, John H M; Parsons, Anthony J

    2014-02-01

    Treating resource allocation within plants, and between plants and associated organisms, is essential for plant, crop and ecosystem modelling. However, it is still an unresolved issue. It is also important to consider quantitatively when it is efficient and to what extent a plant can invest profitably in a mycorrhizal association. A teleonomic model is used to address these issues. A six state-variable model giving exponential growth is constructed. This represents carbon (C), nitrogen (N) and phosphorus (P) substrates with structure in shoot, root and mycorrhiza. The shoot is responsible for uptake of substrate C, the root for substrates N and P, and the mycorrhiza also for substrates N and P. A teleonomic goal, maximizing proportional growth rate, is solved analytically for the allocation fractions. Expressions allocating new dry matter to shoot, root and mycorrhiza are derived which maximize growth rate. These demonstrate several key intuitive phenomena concerning resource sharing between plant components and associated mycorrhizae. For instance, if root uptake rate for phosphorus is equal to that achievable by mycorrhiza and without detriment to root uptake rate for nitrogen, then this gives a faster growing mycorrhizal-free plant. However, if root phosphorus uptake is below that achievable by mycorrhiza, then a mycorrhizal association may be a preferred strategy. The approach offers a methodology for introducing resource sharing between species into ecosystem models. Applying teleonomy may provide a valuable short-term means of modelling allocation, avoiding the circularity of empirical models, and circumventing the complexities and uncertainties inherent in mechanistic approaches. However it is subjective and brings certain irreducible difficulties with it.

  8. Genetic relationships among traits related to reproduction and growth of Nelore females.

    PubMed

    Eler, J P; Bignardi, A B; Ferraz, J B S; Santana, M L

    2014-09-15

    The objective of the study presented here was to analyze the genetic relationships among heifer pregnancy (HP), age at first calving (AFC), stayability (STAY), average annual productivity of the cow, in kilograms of weaned calf per cow per year (PRODAM), postweaning weight gain (PWG), and hip height (HH) of Nelore females from 12 Brazilian herds. (Co)variance components were obtained by six-trait animal model using Gibbs sampling. The posterior mean of the heritability estimates were 0.37, 0.18, 0.19, 0.16, 0.21, and 0.37 for HP, AFC, STAY, PRODAM, PWG, and HH, respectively. In general, the genetic correlations were strong between traits related to reproduction, for example, -0.85 between HP and AFC, and 0.94 between STAY and PRODAM. Weak genetic correlations were obtained between reproductive and growth traits (absolute values ranging from 0.02 to 0.30). Although weak, the genetic correlations between PWG and reproductive traits were favorable, whereas the genetic correlations between HH and reproductive traits were close to zero and slightly unfavorable for HP, AFC, and STAY. An increase of HH is therefore expected to have little or no negative effect on the reproductive performance of females. The posterior mean of genetic correlation between PWG and HH was moderate (0.50). On the basis of the heritability, genetic correlation estimates, and time to obtain data, HP and PRODAM seems to show the best potential as selection criteria to improve the productive and reproductive performance of Nelore females. In principle, it is possible to select for increased PWG without compromising the reproduction of Nelore females. However, selection for PWG may result in an increase of female HH as a correlated response, a fact that could increase management costs in advanced generations of selection. In the light of the results, all traits studied here can be used as selection criteria and there is no strong evidence of genetic antagonism among traits related to reproduction

  9. Growth hormone production and role in the reproductive system of female chicken.

    PubMed

    Hrabia, Anna

    2015-09-01

    The expression and role of growth hormone (GH) in the reproductive system of mammals is rather well established. In birds the limited information thus far available suggests that GH is an endocrine or paracrine/autocrine regulator of ovarian and oviductal functions too. GH and its receptors are expressed in all compartments of the ovary and oviduct and change accordingly to physiological state. The intra-ovarian role of GH likely includes the regulation of steroidogenesis, cell proliferation and apoptosis, the modulation of LH action and the synthesis of IGFs (insulin-like growth factors). In the oviduct, GH is also involved in the regulation of oviduct-specific protein expression. The present study provides a review of current knowledge on the presence and action of GH in the female reproduction, in which it is likely that act in endocrine, autocrine or paracrine mechanisms.

  10. Effects of propagation phenomena and frequency allocation on the growth of satellite communications

    NASA Technical Reports Server (NTRS)

    Freibaum, J.

    1976-01-01

    The development of new allocations and new frequency and orbit sharing criteria for satellite communications below 10 GHz is discussed. These criteria are dependent on the outcome of current spectrum and orbit utilization and propagation studies addressing such problems as intersystem interference, satellite spacing, positioning, and repositioning, spillover of radio signals across geographic boundaries, and the adverse effects of propagation phenomena. These problems are discussed in relation to preparations for the 1979 General World Administrative Radio Conference.

  11. Neuroendocrine and reproductive consequences of overexpression of growth hormone in transgenic mice.

    PubMed

    Bartke, A; Cecim, M; Tang, K; Steger, R W; Chandrashekar, V; Turyn, D

    1994-09-01

    Availability of recombinant growth hormone (GH) and development of long-acting formulations of this material will undoubtedly lead to widespread use of GH in animal industry and in medicine. GH can act, directly or indirectly, on multiple targets, but its influence on the reproductive system and on the hormonal control of reproduction is poorly understood. Overexpression of GH genes in transgenic animals provides a unique opportunity to study the effects of long-term GH excess. Transgenic mice overexpressing bovine, ovine, or rat GH (hormones with actions closely resembling, if not identical to, those of endogenous [mouse] GH), exhibit enhancement of growth, increased adult body size, and reduced life-span as well as a number of endocrine and reproductive abnormalities. Ectopic overexpression of bovine GH (bGH) driven by metallothionein or phosphoenolpyruvate carboxykinase promoters is associated with altered activity of hypothalamic neurons which produce somatostatin, loss of adenohypophyseal GH releasing hormone (GHRH) receptors, and suppression of endogenous (mouse) GH release. Elevation of plasma levels of GH (primarily bGH) and insulin-like growth factor (IGF-I) in these transgenic mice leads to increases in the number of hepatic GH and prolactin (PRL) receptors, in the serum levels of GH-binding protein (GHBP), in the percent of GHBP complexed with GH, and in the circulating insulin levels. In addition, plasma adrenocorticotropic hormone (ACTH) and corticosterone levels are elevated. Plasma levels of luteinizing hormone (LH), as well as its synthesis and release, are not consistently affected, but follicle-stimulating hormone (FSH) levels are suppressed, apparently due to pre- and post-translational effects. Pituitary lactotrophs exhibit characteristics of chronic enhancement of secretory activity, and plasma PRL levels are elevated. Prolactin responses to mating or to pharmacological blockade of dopamine synthesis are abnormal. Reproductive life span and

  12. Energy allocation strategy modifies growth-survival trade-offs in juvenile fish across ecological and environmental gradients.

    PubMed

    Mogensen, Stephanie; Post, John R

    2012-04-01

    In young temperate zone fishes, conflicting energy demands lead to variability in growing season and winter survival. Growing season survival is driven by size-dependent predation risk whereas winter survival is constrained by autumn body size, energy storage and winter duration. We developed a model of the seasonality of energetics coupled to empirical measures of resource availability, size-dependent predation and temperature seasonality for rainbow trout (Oncorhynchus mykiss) in two sets of lakes in British Columbia, Canada, representing endpoints of a gradient of temperature, growing season duration and winter duration. This model was used to determine the energy allocation strategy which maximized first-year survival across these gradients. Survival was sensitive to the timing of the switch from somatic to storage strategies in cold, short growing season, low resource environments. A broader range of energy allocation strategies were viable in warmer, longer growing season and higher resource lakes. We used empirical observations of autumn energy storage and our modeled values for size-dependent minimal lipid levels needed to survive winter in each system to estimate winter survival for juvenile rainbow trout. Winter survival estimates were 6% in cold lakes with low resources, 82% in warm, lakes with low resources and 100% in warm lakes with high resources. Fish in warm lakes with ample resources allocated substantially more to storage than the minimum required to survive winter generated from our model, suggesting additional selection pressures for increased storage when there was ample surplus energy. We concluded that growth-survival trade-offs, modified by seasonality of the environment, influenced the growing season energy allocation strategies for young-of-the-year fish, and suggested this may be important for understanding population viability across environmental gradients.

  13. Reproductive toxicity and growth effects in rats exposed to lead at different periods during development.

    PubMed

    Ronis, M J; Badger, T M; Shema, S J; Roberson, P K; Shaikh, F

    1996-02-01

    The reproductive toxicity and growth effects of developmental lead exposure were assessed using a rat model in which 0.6% (w/v) lead acetate was administered in the drinking water ad libitum. Three series of experiments were conducted in which lead exposure was initiated beginning in utero, prepubertally, or postpubertally. Lead effects were measured on reproductive physiology and endocrinology, sexually dimorphic hepatic testosterone hydroxylation, and growth rates in both male and female animals. In male animals secondary sex organ weights were significantly decreased only in animals exposed prepubertally. In addition, serum testosterone levels were significantly suppressed, most severely in animals exposed from in utero (in the in utero group). Little effect was observed in adult female rats. However, in female animals exposed prepubertally, delayed vaginal opening and disrupted estrus cycling was observed. More severe reproductive disruption was accompanied by suppression of circulating estradiol in the in utero group. Effects on circulating sex steroids were accompanied by variable effects on circulating luteinizing hormone (LH) levels, pituitary LH, and pituitary LH beta mRNA, suggesting a dual site of lead action: (a) at the level of the hypothalamic pituitary unit, and (b) directly at the level of gonadal steroid biosynthesis. Prepubertal growth in both sexes was suppressed 25% in the in utero group. However, pubertal growth rates were significantly suppressed only in male animals and postpubertal growth was not significantly different from controls in any of the experiments, despite continued exposure to high lead levels in the drinking water. In addition, at age 85 days, male-specific hepatic hydroxylation of testosterone at positions 2 alpha and 16 alpha, which is catalyzed by a cytochrome P450 isozyme CYP 2C11, itself regulated by sexually dimorphic growth hormone secretion, was unaffected. This suggests that the growth effects of lead are possibly due

  14. Effect of environmental temperature on growth- and reproduction-related hormones gene expression in the female blue gourami (Trichogaster trichopterus).

    PubMed

    Levy, Gal; David, Dalia; Degani, Gad

    2011-11-01

    Fish are ectothermic vertebrates, and their gonadal development and spawning are affected by changes in environmental temperature. Recent global temperature changes have increased the importance of studying the effect of temperature on reproduction. The aim of this paper was to study the effect of temperature on oogenesis and hormone gene expression related to reproduction and growth in the blue gourami female maintained under non-reproductive and reproductive conditions. In females under non-reproductive conditions, vitellogenic oocytes, gonadotropin-releasing hormone 3 (GnRH3), β luteinizing hormone (βLH) and growth hormone (GH) mRNA levels were affected by temperature changes. In females maintained under reproductive conditions with non-reproductively active males, a percentage of females in the final oocyte maturation (FOM) stage, pituitary adenylyl cyclase activating polypeptide (PACAP and PRP-PACAP), gonadotropins and GH mRNA levels were affected due to temperature changes. In females maintained under reproductive conditions with reproductively active males, also GnRH3 and insulin-like growth factor 1 (IGF-1) were affected by temperature changes. In conclusion, in blue gourami females, changes in environmental temperature affect oogenesis through changes in brain and pituitary hormone mRNA levels.

  15. Multigenerational Effects of Heavy Metals on Feeding, Growth, Initial Reproduction and Antioxidants in Caenorhabditis elegans

    PubMed Central

    Yu, ZhenYang; Zhang, Jing; Yin, DaQiang

    2016-01-01

    Earlier studies showed that toxicities of excessive metals lasted over generations. Yet, these studies mainly employed one-generation exposure, and the effects of multigenerational challenges need further studies. Presently, Caenorhabditis elegans were exposed to cadmium, copper, lead and zinc for four consecutive generations (G1 to G4) at environmental concentrations. The feeding, growth, initial reproduction, superoxide dismutase (SOD) and catalase (CAT) were determined. All data were represented in the percentage of that in control (POC), and POC in the control was normalized to 100%. In G1 and G2, the POC values in feeding, growth and initial reproduction were generally within 10% of the control (100%), indicating non-significant effects. The POC values in SOD and CAT were significantly higher than 100%, showing stimulatory effects. In G3 and G4, the POC values in feeding, growth and initial reproduction were significantly lower than 100%, showing inhibitory effects which were more severe in G4 than in G3. Meanwhile, SOD and CAT continuously showed stimulatory effects, and the stimulatory effects on SOD increased from G1 to G4. The effects with multigenerational challenges were different from those in one-generation exposure. The effects in later generations demonstrated the importance of multigenerational challenges in judging long-term influences of metals. PMID:27116222

  16. Androgen Receptors Expression in Pituitary of Male Viscacha in relation to Growth and Reproductive Cycle

    PubMed Central

    Filippa, Verónica Palmira; Rosales, Gabriela Judith; Cruceño, Albana Andrea Marina; Mohamed, Fabian Heber

    2015-01-01

    The aim of this work was to study the androgen receptors (AR) expression in pituitary pars distalis (PD) of male viscachas in relation to growth and reproductive cycle. AR were detected by immunocytochemistry and quantified by image analysis. Pituitary glands from fetus, immature, prepubertal, and adult viscachas during their reproductive cycle were used. In the fetal PD, the immunoreactivity (ir) was mainly cytoplasmic. In immature and prepubertal animals, AR-ir was cytoplasmic (ARc-ir) and nuclear (ARn-ir) in medial region. In adult animals, ARn-ir cells were numerous at caudal end. AR regionalization varied between the PD zones in relation to growth. In immature animals, the ARn-ir increased whereas the cytoplasmic expression decreased in relation to the fetal glands. The percentage of ARc-ir cells increased in prepubertal animals whereas the nuclear AR expression was predominant in adult viscachas. The AR expression changed in adults, showing minimum percentage in the gonadal regression period. The variation of nuclear AR expression was directly related with testosterone concentration. These results demonstrated variations in the immunostaining pattern, regionalization, and number of AR-ir cells throughout development, growth, and reproductive cycle, suggesting the involvement of AR in the regulation of the pituitary activity of male viscacha. PMID:25945090

  17. Effects of growth hormone over-expression on reproduction in the common carp Cyprinus carpio L.

    PubMed

    Cao, Mengxi; Chen, Ji; Peng, Wei; Wang, Yaping; Liao, Lanjie; Li, Yongming; Trudeau, Vance L; Zhu, Zuoyan; Hu, Wei

    2014-01-01

    To study the complex interaction between growth and reproduction we have established lines of transgenic common carp (Cyprinus carpio) carrying a grass carp (Ctenopharyngodon idellus) growth hormone (GH) transgene. The GH-transgenic fish showed delayed gonadal development compared with non-transgenic common carp. To gain a better understanding of the phenomenon, we studied body growth, gonad development, changes of reproduction related genes and hormones of GH-transgenic common carp for 2years. Over-expression of GH elevated peripheral gh transcription, serum GH levels, and inhibited endogenous GH expression in the pituitary. Hormone analyses indicated that GH-transgenic common carp had reduced pituitary and serum level of luteinizing hormone (LH). Among the tested genes, pituitary lhβ was inhibited in GH-transgenic fish. Further analyses in vitro showed that GH inhibited lhβ expression. Localization of ghr with LH indicates the possibility of direct regulation of GH on gonadotrophs. We also found that GH-transgenic common carp had reduced pituitary sensitivity to stimulation by co-treatments with a salmon gonadotropin-releasing hormone (GnRH) agonist and a dopamine antagonist. Together these results suggest that the main cause of delayed reproductive development in GH transgenic common carp is reduced LH production and release.

  18. The significance of growth in Chironomus tentans sediment toxicity tests: Relationship to reproduction and demographic endpoints

    SciTech Connect

    Sibley, P.K.; Benoit, D.A.; Ankley, G.T.

    1995-12-31

    This study assessed the biological relevance of growth, as used in sediment toxicity bioassessment, through evaluation of the relationship between growth and reproduction in the midge C. tentans. Newly-hatched larvae were fed one of six food levels (3.5, 4.0, 4.5, 5.0, 5.5, 6.0 mg Tetrafin fish food) on a daily basis for one complete generation. Larvae were exposed in 300 ml beakers containing 100 ml of 75/{micro}m sand housed within an intermittent water renewal system. Food supply had no effect on larval (65--82%), pupal (93--95%), or adult (90--98%) survivorship. Larval growth and adult weight decreased significantly (p{<=}0.05) with decreasing food supply (r{sup 2} = 0.92, 0.91 respectively). The data suggest that a threshold larval dry weight of approximately 0.6 mg must be obtained for emergence to occur. This value also corresponded to the approximate minimum adult weight observed in this study. Emergence rate and total emergence were delayed at lower feeding levels; however, total emergence was not less than 60% for any treatment. Egg mass production, oviposition rate, and mean number of eggs produced per female declined significantly with reduced food supply. Larval growth and adult weight were significantly correlated with age-specific fecundity (r{sup 2} = 0.96). Application of the reproductive data in a demographic model showed that the expected number of offspring recruited to subsequent generations declined significantly with a decrease in food supply. The results of this study demonstrate a direct relationship between growth and reproduction in C. tentans and clearly emphasize the biological and ecological relevance of the growth endpoint in sediment toxicity bioassessment.

  19. Impact of growth hormone resistance on female reproductive function: new insights from growth hormone receptor knockout mice.

    PubMed

    Zaczek, Denise; Hammond, James; Suen, Lii; Wandji, Serge; Service, Darlene; Bartke, Andrzej; Chandrashekar, Varadaraj; Coschigano, Karen; Kopchick, John

    2002-10-01

    We examined multiple aspects of reproductive function in growth hormone receptor gene knockout (GHR-KO) and normal mice to clarify the role of growth hormone in female reproduction. In adult animals, estrous cycle duration was comparable in all mice housed individually but was significantly longer in group-housed GHR-KO females. Histological evaluation of ovaries of adult females at estrus showed that the numbers of preovulatory follicles and corpora lutea were significantly reduced in GHR-KO mice, as was the plasma estradiol level. The number of atretic preovulatory follicles was reduced in GHR gene-ablated animals. Although reverse transcription polymerase chain reaction analysis revealed reduced ovarian insulin-like growth factor I (IGF-I) mRNA expression in GHR-KO females, the expression of several steroidogenic enzyme mRNAs did not differ between groups. The numbers of active corpora lutea and uterine implantation sites were reduced in GHR-KO females at Day 7 of gestation. When young females were mated to normal males, latency to first mating and age of the female at first mating were significantly delayed in GHR-KO females, but maternal age at first conception was similar between groups. Significantly fewer virgin GHR-KO females exhibited pseudopregnancies when initially placed with vasectomized normal males than did normal female counterparts. Growth hormone resistance and IGF-I insufficiency negatively impacted 1) follicular development/ovulation rate, 2) sexual maturation, 3) production of and responsiveness to pheromonal signals, and 4) the ability of virgin females to respond to coitus by activation of luteal function. Although GHR-KO female mice are fertile, they exhibit quantitative deficits in various parameters of reproductive function.

  20. Fisheries-induced evolution in growth, maturation and reproductive investment of the sexually dimorphic North Sea plaice ( Pleuronectes platessa L.)

    NASA Astrophysics Data System (ADS)

    van Walraven, L.; Mollet, F. M.; van Damme, C. J. G.; Rijnsdorp, A. D.

    2010-07-01

    Changes in the onset of sexual maturation, reproductive investment and growth of North Sea plaice are studied between three periods: 1900s, 1980s and 2000s. Probabilistic maturation reaction norms of both males and females, describing the probability of becoming mature conditional on age and size, shifted towards smaller sizes and younger ages, indicating a fisheries-induced evolutionary change. A higher rate of change was observed during the past 20 years, which may be related to higher temperature conditions. Reproductive investment was estimated from the decrease in lipid, protein, dry weight content and condition factor of the whole body between pre- and post-spawning adults. Reproductive investment expressed as the energy loss over the spawning period increased with body size from 19% at 20 cm to 30% at 40 cm in males and from 35% at 30 cm to 48% at 50 cm in females. No change in reproductive investment could be detected between the 1980s and the 2000s. Von Bertalanffy (VB) growth parameters showed a decrease in L∞ the asymptotic size and an increase in K, the velocity to reach L∞, in both males and females. The changes in VB growth are consistent with an increase in energy acquisition and reproductive investment. The observed changes in maturation, reproductive investment and growth are consistent with fisheries-induced evolution, but the changes in reproductive investment and growth need further investigation to disentangle the role of phenotypic plasticity.

  1. Impacts of breeder loss on social structure, reproduction and population growth in a social canid.

    PubMed

    Borg, Bridget L; Brainerd, Scott M; Meier, Thomas J; Prugh, Laura R

    2015-01-01

    The importance of individuals to the dynamics of populations may depend on reproductive status, especially for species with complex social structure. Loss of reproductive individuals in socially complex species could disproportionately affect population dynamics by destabilizing social structure and reducing population growth. Alternatively, compensatory mechanisms such as rapid replacement of breeders may result in little disruption. The impact of breeder loss on the population dynamics of social species remains poorly understood. We evaluated the effect of breeder loss on social stability, recruitment and population growth of grey wolves (Canis lupus) in Denali National Park and Preserve, Alaska using a 26-year dataset of 387 radiocollared wolves. Harvest of breeding wolves is a highly contentious conservation and management issue worldwide, with unknown population-level consequences. Breeder loss preceded 77% of cases (n = 53) of pack dissolution from 1986 to 2012. Packs were more likely to dissolve if a female or both breeders were lost and pack size was small. Harvest of breeders increased the probability of pack dissolution, likely because the timing of harvest coincided with the breeding season of wolves. Rates of denning and successful recruitment were uniformly high for packs that did not experience breeder loss; however, packs that lost breeders exhibited lower denning and recruitment rates. Breeder mortality and pack dissolution had no significant effects on immediate or longer term population dynamics. Our results indicate the importance of breeding individuals is context dependent. The impact of breeder loss on social group persistence, reproduction and population growth may be greatest when average group sizes are small and mortality occurs during the breeding season. This study highlights the importance of reproductive individuals in maintaining group cohesion in social species, but at the population level socially complex species may be resilient

  2. Growth and carbon allocation of tropical and temperate N-fixing trees grown in elevated CO{sub 2}

    SciTech Connect

    Tissue, D.T.; Megonigal, J.P.; Thomas, R.B.

    1995-09-01

    Seeds of two tree species, Gliricidia seplum (tropical) and Robinia pseudoacacia (temperate), were inoculated with N-fixing Rhizobium bacteria and grown in environmentally controlled glasshouses for 75 days to determine the effects of atmospheric CO{sub 2} on seedling growth and carbon allocation. Seedlings were grown in ambient CO{sub 2}(35 Pa) and elevated CO{sub 22}(70 Pa) and watered with a N-deficient nutrient solution such that bacterial N-fixation was the only source of N. Elevated CO{sub 2} increased leaf, stem, root and total biomass in Gliricidia, but did not affect nodule mass; Robinia biomass was unchanged by CO{sub 2}. Leaf photosynthetic rates at 70 Pa CO{sub 2} were increased 49% in Gliricidia, but were unchanged in Robinia, and there was no change in respiration rate in either species. A {sup 14}CO{sub 2} labelling experiment demonstrated that elevated CO{sub 2} did not affect the kinetics or allocation patterns of photosynthetically fixed carbon to nodules or other plant parts in either species. Our results demonstrate that Gliricidia, but not Robinia, will show an early, positive growth and photosynthetic response to elevated CO{sub 2} in N-poor soils, suggesting that tropical N-fixing trees may be more responsive than temperate N-fixing trees to future atmospheric CO{sub 2} conditions.

  3. Phenotypic and genotypic components of growth and reproduction in Typha latifolia: experimental studies in three contrasting marshes

    SciTech Connect

    Grace, J.B.

    1980-01-01

    The magnitude and causes of intraspecific variation in biomass production and allocation, and morphology for Typha latifolia L. from three marshes which can be distinguished by their successional maturity were investigated. The first stage of investigation was to determine the environmental characteristics of the three marshes and the characteristics of the T. latifolia populations. Second, in situ studies of /sup 14/C fixation and allocation were used to determine the phenotypic variation in biomass production and allocation. Third, populations were sampled for genotypic variation in biomass allocation patterns by comparing growth in controlled garden experiments. Fourth, the growth of different biotypes was compared by transplantation into natural stands of T. latifolia. And fifth, the intraspecific variations were considered in terms of their consequences for the persistence of T. latifolia in habitats over successional time.

  4. Cyclic variations in nitrogen uptake rate in soybean plants: uptake during reproductive growth

    NASA Technical Reports Server (NTRS)

    Vessey, J. K.; Raper, C. D. Jr; Henry, L. T.; Raper CD, J. r. (Principal Investigator)

    1990-01-01

    Net uptake of NO3- by non-nodulated soybean plants [Glycine max (L.) Merr. cv. Ransom] growing in flowing hydroponic culture was measured daily during a 63 d period of reproductive development between the first florally inductive photoperiod and [unknown word] seed growth. Removal of NO3- from a replenished solution containing 1.0 mol m-3 NO3- was determined by ion chromatography. Uptake of NO3- continued throughout reproductive development. The net uptake rate of NO3- cycled between maxima and minima with a periodicity of oscillation of 3 to 7 d during the floral stage and about 6 d during the fruiting stage. Coupled with increasing concentrations of carbon and C : N ratios in tissues, the oscillations in net uptake rates of NO3- are evidence that the demand for carbohydrate by reproductive organs is contingent on the availability of nitrogen in the shoot pool rather than that the demand for nitrogen follows the flux of carbohydrate into reproductive tissues.

  5. [Effects of substrate nitrogen and phosphorus contents on Potamogeton crispus growth and reproduction].

    PubMed

    Huang, Wei; Chen, Kai-ning; Bai, Xiang

    2010-11-01

    Six nutritional levels were designed to study the effects of different nitrogen (N) and phosphorus (P) contents in sediment on the growth and reproduction of Potamogeton crispus. The results revealed that the germination rate of P. crispus was not affected by the N and P contents in sediment, and all reached 100%. With the increasing N and P contents in sediment, the N content in plant tissues increased first and approached to a stationary level then, while the P content presented a slow increasing trend. In the meantime, the initial fluorescence (Fo) declined rapidly, while the potential maximum quantum yield (Fv/Fm) increased first followed by a slight decrease, indicating that the photosynthetic efficiency was enhanced by the increasing N and P contents in sediment but decreased at excessively high N and P contents. The rapid light curves showed that P. crispus could effectively use weak light and was more susceptible to photoinhibition under intense light, but its resistance capability against intense light could be improved by the high N and P contents in sediment. The high N and P contents in sediment could also promote the total biomass of P. crispus, but reduce the root: shoot ratio of the plant. Under the increasing N and P contents in sediment, the asexual reproduction of P. crispus was improved, reproductive strategy was optimized, and also, the sexual reproduction occurred but the seed setting rate was low, only 19.6% on average.

  6. Effect of bovine colostrum intake on growth, reproductive parameters and survival in red kids.

    PubMed

    Abdou, H; Marichatou, H; Beckers, J-F; Dufrasne, I; Issa, M; Hornick, J-L

    2014-10-01

    The aim of this study is to evaluate the efficacy of frozen Azawak colostrum supplementation on body weight (BW), average daily gain (ADG), reproductive parameters (mean age at first parturition, fertility, fecundity, prolificacy) and mortality rate among red kids. The study was conducted at the goat farm secondary centre of Maradi in Niger from September 2010 to September 2011. The control animals (n = 20) were left with their mother, while the treatment animals (n = 20) received in addition 50 ml/animal/day of bovine colostrum at birth and 15 ml/animal/day from d2 to d15. Weight was measured weekly from birth to d365. Mortalities were also recorded over the same period. For reproductive parameters, observations began at weaning (d197). Growth rate was higher (p < 0.001) in supplemented animal, and the treatment effects on ADG were observed up to 150 day after the end of supplementation. A similar long-lasting trend was also observed in relation to the mortality rate (25% for ColG vs. 55% for ConG; p = 0.05). The age at first kidding tended to be lower in the treated group (13.8 ± 0.7 vs. 14.1 ± 0.8 month; p < 0.1). In conclusion, mild bovine colostrum supplementation induces a long-lasting positive impact on growth rate and to a lower extent on reproduction parameters and survival rate. PMID:25356485

  7. Effects of lithium on the survival, growth, and reproduction of Daphniopsis tibetana Sars (Crustacea: Cladocera)

    NASA Astrophysics Data System (ADS)

    Zhao, Wen; Huo, Yuanzi; Zhang, Tianmin; Wang, Shan; Shi, Tingting

    2016-08-01

    We evaluated the effects of lithium on the survival, growth, and reproduction of D. tibetana in the laboratory. The safe concentration value was 69.3 mg/L. The time to first brood was significant lower for individuals reared in 5 and 10 mg/L (24.4 and 24.0 d, respectively) compared with individuals reared in 20, 40, or 60 mg/L. Females reared in 5 mg/L lithium produced a mean of 16.5 neonates/brood and had the highest number of broods (3.0±1.95). The rate of egg production (a), the intrinsic rate of increase (r m ), net reproduction rate (R 0), and finite rate of increase (λ) were highest for D. tibetana reared at 5 and 10 mg/L lithium, and the duration of development was shorter than for the remaining groups. The results indicated that rearing in 5-10 mg/L lithium can accelerate the growth and reproduction of D. tibetana.

  8. Chronic ingestion of cadmium and/or tritium. II. Effects on growth, development, and reproductive function

    SciTech Connect

    Laskey, J.W.; Rehnberg, G.L.; Favor, M.J.; Cahill, D.F.; Pietrzak-Flis, Z.

    1980-08-01

    The effects of chronic low-level exposure to cadmium (Cd) and/or tritium (HTO) on the growth and reproduction were evaluated in Sprague-Dawley rats. Cadmium exposure levels ranged from less than 0.1 to 5.0 ppM as CdCl/sub 2/ in the drinking water, while HTO concentrations ranged from less than 0.1 to 13.0 ..mu..Ci/ml. Exposures were started with conception of the first generation. Both insults, at the higher doses, resulted in depressed adult body weight. Chronic Cd exposure caused liver weight decrements and a decrease in sperm counts. HTO effects were manifested in a depression of several reproductive parameters and brain weights in the F/sub 2/ neonates. Synergistic effects of simultaneous exposure were minimal.

  9. Survival, reproductive, and growth responses in fish to creosote exposure in aquatic mesocosms

    SciTech Connect

    Munro, K.A.; Solomon, K.R.; Bestari, K.T.; Robinson, R.D.

    1995-12-31

    Creosote is a coal tar distillate, consisting mainly of a mixture of polyaromatic hydrocarbons (PAHs). Its widespread use as a wood preservative presents a potential risk to aquatic ecosystems. The use of mesocosms (precolonized with zooplankton, phytoplankton, macroinvertebrates, and periphyton) enabled evaluation of the total impact of creosote exposure, resulting from both direct toxic effects and indirect community-level interactions. Two methods of creosote addition were used, resulting in two series of mesocosm exposures: sixteen ponds were dosed with liquid creosote (from 0 to 100 ppm), and eight were dosed using creosote impregnated pilings (0 to 6 pilings per pond). In addition to growth and survival in two species of fish, Carassius auratus and Pimephales promelas, a number of reproductive parameters were measured (reproductive hormones, egg production, hatching success, and weight/frequency distribution of juveniles).

  10. Asexual endophytes in a native grass: tradeoffs in mortality, growth, reproduction, and alkaloid production.

    PubMed

    Faeth, Stanley H; Hayes, Cinnamon J; Gardner, Dale R

    2010-10-01

    Neotyphodium endophytes are asexual, seed-borne fungal symbionts that are thought to interact mutualistically with their grass hosts. Benefits include increased growth, reproduction, and resistance to herbivores via endophytic alkaloids. Although these benefits are well established in infected introduced, agronomic grasses, little is known about the cost and benefits of endophyte infection in native grass populations. These populations exist as mosaics of uninfected and infected plants, with the latter often comprised of plants that vary widely in alkaloid content. We tested the costs and benefits of endophyte infections with varying alkaloids in the native grass Achnatherum robustum (sleepygrass). We conducted a 4-year field experiment, where herbivory and water availability were controlled and survival, growth, and reproduction of three maternal plant genotypes [uninfected plants (E-), infected plants with high levels of ergot alkaloids (E+A+), and infected plants with no alkaloids (E+A-)] were monitored over three growing seasons. Generally, E+A+ plants had reduced growth over the three growing seasons and lower seed production than E- or E+A- plants, suggesting a cost of alkaloid production. The reduction in vegetative biomass in E+A+ plants was most pronounced under supplemented water, contrary to the prediction that additional resources would offset the cost of alkaloid production. Also, E+A+ plants showed no advantage in growth, seed production, or reproductive effort under full herbivory relative to E- or E+A- grasses, contrary to the predictions of the defensive mutualism hypothesis. However, E+A+ plants had higher overwintering survival than E+A- plants in early plant ontogeny, suggesting that alkaloids associated with infection may protect against below ground herbivory or harsh winter conditions. Our results suggest that the mosaic of E-, E+A+, and E+A- plants observed in nature may result from varying biotic and abiotic selective factors that maintain

  11. A Minimalistic Resource Allocation Model to Explain Ubiquitous Increase in Protein Expression with Growth Rate

    PubMed Central

    Keren, Leeat; Segal, Eran; Milo, Ron

    2016-01-01

    Most proteins show changes in level across growth conditions. Many of these changes seem to be coordinated with the specific growth rate rather than the growth environment or the protein function. Although cellular growth rates, gene expression levels and gene regulation have been at the center of biological research for decades, there are only a few models giving a base line prediction of the dependence of the proteome fraction occupied by a gene with the specific growth rate. We present a simple model that predicts a widely coordinated increase in the fraction of many proteins out of the proteome, proportionally with the growth rate. The model reveals how passive redistribution of resources, due to active regulation of only a few proteins, can have proteome wide effects that are quantitatively predictable. Our model provides a potential explanation for why and how such a coordinated response of a large fraction of the proteome to the specific growth rate arises under different environmental conditions. The simplicity of our model can also be useful by serving as a baseline null hypothesis in the search for active regulation. We exemplify the usage of the model by analyzing the relationship between growth rate and proteome composition for the model microorganism E.coli as reflected in recent proteomics data sets spanning various growth conditions. We find that the fraction out of the proteome of a large number of proteins, and from different cellular processes, increases proportionally with the growth rate. Notably, ribosomal proteins, which have been previously reported to increase in fraction with growth rate, are only a small part of this group of proteins. We suggest that, although the fractions of many proteins change with the growth rate, such changes may be partially driven by a global effect, not necessarily requiring specific cellular control mechanisms. PMID:27073913

  12. Nitrogen, phosphorus and light effects on growth and allocation of biomass and nutrients in wild rice.

    PubMed

    Sims, Lee; Pastor, John; Lee, Tali; Dewey, Brad

    2012-09-01

    Separating plastic from ontogenetic and growth-limiting responses of plants to changes in resource availability can be challenging because there are a total of eight combinations of these three types of responses. These can, however, be uniquely distinguished on plots of root:shoot ratios against total biomass through time. We used this approach to separate ontogenetic, plastic, and growth-limiting responses of wild rice (Zizania palustris L.) to changes in nitrogen, phosphorus, and light availabilities. Relative growth rate was limited primarily by nitrogen but responded to increased light and phosphorus after nitrogen limitations were alleviated. Nitrogen addition increased relative growth rate because it simultaneously increased unit leaf rate, specific leaf area, and leaf weight ratio. Increased light did not change relative growth rate because decreased specific leaf area and leaf weight ratio compensated the increased unit leaf rate. Phosphorus did not change either relative growth rate or its underlying components. Plants responded ontogenetically to increased nitrogen and light availabilities by accelerating their developmental rate, and plastically by decreasing or increasing their root:shoot ratios, respectively. Plants did not respond either ontogenetically or plastically to increased phosphorus availability. Ontogenetic changes in growth can be separated from plastic and growth-limiting responses by plotting root:shoot ratio against total biomass in the context of the eight possible responses identified above, and also by examining how the underlying components of relative growth rate respond.

  13. Survival, growth and reproduction of cryopreserved larvae from a marine invertebrate, the Pacific oyster (Crassostrea gigas).

    PubMed

    Suquet, Marc; Labbé, Catherine; Puyo, Sophie; Mingant, Christian; Quittet, Benjamin; Boulais, Myrina; Queau, Isabelle; Ratiskol, Dominique; Diss, Blandine; Haffray, Pierrick

    2014-01-01

    This study is the first demonstration of successful post-thawing development to reproduction stage of diploid cryopreserved larvae in an aquatic invertebrate. Survival, growth and reproductive performances were studied in juvenile and adult Pacific oysters grown from cryopreserved embryos. Cryopreservation was performed at three early stages: trochophore (13±2 hours post fertilization: hpf), early D-larvae (24±2 hpf) and late D-larvae (43±2 hpf). From the beginning (88 days) at the end of the ongrowing phase (195 days), no mortality was recorded and mean body weights did not differ between the thawed oysters and the control. At the end of the growing-out phase (982 days), survival of the oysters cryopreserved at 13±2 hpf and at 43±2 hpf was significantly higher (P<0.001) than those of the control (non cryopreserved larvae). Only the batches cryopreserved at 24±2 hpf showed lower survival than the control. Reproductive integrity of the mature oysters, formely cryopreserved at 13±2 hpf and 24±2 hpf, was estimated by the sperm movement and the larval development of their offspring in 13 crosses gamete pools (five males and five females in each pool). In all but two crosses out of 13 tested (P<0.001), development rates of the offspring were not significantly different between frozen and unfrozen parents. In all, the growth and reproductive performances of oysters formerly cryopreserved at larval stages are close to those of controls. Furthermore, these performances did not differ between the three initial larval stages of cryopreservation. The utility of larvae cryopreservation is discussed and compared with the cryopreservation of gametes as a technique for selection programs and shellfish cryobanking.

  14. Placental phenotype and resource allocation to fetal growth are modified by the timing and degree of hypoxia during mouse pregnancy

    PubMed Central

    Higgins, J. S.; Vaughan, O. R.; Fernandez de Liger, E.; Fowden, A. L.

    2015-01-01

    Key points Hypoxia is a major cause of fetal growth restriction, particularly at high altitude, although little is known about its effects on placental phenotype and resource allocation to fetal growth.In the present study, maternal hypoxia induced morphological and functional changes in the mouse placenta, which depended on the timing and severity of hypoxia, as well as the degree of maternal hypophagia.Hypoxia at 13% inspired oxygen induced beneficial changes in placental morphology, nutrient transport and metabolic signalling pathways associated with little or no change in fetal growth, irrespective of gestational age.Hypoxia at 10% inspired oxygen adversely affected placental phenotype and resulted in severe fetal growth restriction, which was due partly to maternal hypophagia.There is a threshold between 13% and 10% inspired oxygen, corresponding to altitudes of ∼3700 m and 5800 m, respectively, at which the mouse placenta no longer adapts to support fetal resource allocation. This has implications for high altitude human pregnancies. Abstract The placenta adapts its transport capacity to nutritional cues developmentally, although relatively little is known about placental transport phenotype in response to hypoxia, a major cause of fetal growth restriction. The present study determined the effects of both moderate hypoxia (13% inspired O2) between days (D)11 and D16 or D14 and D19 of pregnancy and severe hypoxia (10% inspired O2) from D14 to D19 on placental morphology, transport capacity and fetal growth on D16 and D19 (term∼D20.5), relative to normoxic mice in 21% O2. Placental morphology adapted beneficially to 13% O2; fetal capillary volume increased at both ages, exchange area increased at D16 and exchange barrier thickness reduced at D19. Exposure to 13% O2 had no effect on placental nutrient transport on D16 but increased placental uptake and clearance of 3H‐methyl‐d‐glucose at D19. By contrast, 10% O2 impaired fetal vascularity

  15. EFFECTS OF CARBON DIOXIDE AND OZONE ON GROWTH AND BIOMASS ALLOCATION IN PINUS PONDEROSA

    EPA Science Inventory

    The future productivity of forests will be affected by combinations of elevated atmospheric CO2 and O3. Because productivity of forests will, in part, be determined by growth of young trees, we evaluated shoot growth and biomass responses of Pinus ponderosa seedlings exposed to ...

  16. Long-term hyperphagia and caloric restriction caused by low- or high-density husbandry have differential effects on zebrafish postembryonic development, somatic growth, fat accumulation and reproduction.

    PubMed

    Leibold, Sandra; Hammerschmidt, Matthias

    2015-01-01

    In recent years, the zebrafish (Danio rerio) has emerged as an alternative vertebrate model for energy homeostasis and metabolic diseases, including obesity and anorexia. It has been shown that diet-induced obesity (DIO) in zebrafish shares multiple pathophysiological features with obesity in mammals. However, a systematic and comprehensive analysis of the different pathways of energy expenditure in obese and starved fish had been missing thus far. Here, we carry out long-term ad libitum feeding (hyperphagia) and caloric restriction studies induced by low- or high-density husbandry, respectively, to investigate the impact of caloric intake on the timing of scale formation, a crucial step of postembryonic development and metamorphosis, and on somatic growth, body weight, fat storage and female reproduction. We show that all of them are positively affected by increased caloric intake, that middle-aged fish develop severe DIO, and that the body mass index (BMI) displays a strict linear correlation with whole-body triglyceride levels in adult zebrafish. Interestingly, juvenile fish are largely resistant to DIO, while BMI and triglyceride values drop in aged fish, pointing to aging-associated anorexic effects. Histological analyses further indicate that increased fat storage in white adipose tissue involves both hyperplasia and hypertrophy of adipocytes. Furthermore, in ovaries, caloric intake primarily affects the rate of oocyte growth, rather than total oocyte numbers. Finally, comparing the different pathways of energy expenditure with each other, we demonstrate that they are differentially affected by caloric restriction / high-density husbandry. In juvenile fish, scale formation is prioritized over somatic growth, while in sexually mature adults, female reproduction is prioritized over somatic growth, and somatic growth over fat storage. Our data will serve as a template for future functional studies to dissect the neuroendocrine regulators of energy homeostasis

  17. Long-Term Hyperphagia and Caloric Restriction Caused by Low- or High-Density Husbandry Have Differential Effects on Zebrafish Postembryonic Development, Somatic Growth, Fat Accumulation and Reproduction

    PubMed Central

    Leibold, Sandra; Hammerschmidt, Matthias

    2015-01-01

    In recent years, the zebrafish (Danio rerio) has emerged as an alternative vertebrate model for energy homeostasis and metabolic diseases, including obesity and anorexia. It has been shown that diet-induced obesity (DIO) in zebrafish shares multiple pathophysiological features with obesity in mammals. However, a systematic and comprehensive analysis of the different pathways of energy expenditure in obese and starved fish had been missing thus far. Here, we carry out long-term ad libitum feeding (hyperphagia) and caloric restriction studies induced by low- or high-density husbandry, respectively, to investigate the impact of caloric intake on the timing of scale formation, a crucial step of postembryonic development and metamorphosis, and on somatic growth, body weight, fat storage and female reproduction. We show that all of them are positively affected by increased caloric intake, that middle-aged fish develop severe DIO, and that the body mass index (BMI) displays a strict linear correlation with whole-body triglyceride levels in adult zebrafish. Interestingly, juvenile fish are largely resistant to DIO, while BMI and triglyceride values drop in aged fish, pointing to aging-associated anorexic effects. Histological analyses further indicate that increased fat storage in white adipose tissue involves both hyperplasia and hypertrophy of adipocytes. Furthermore, in ovaries, caloric intake primarily affects the rate of oocyte growth, rather than total oocyte numbers. Finally, comparing the different pathways of energy expenditure with each other, we demonstrate that they are differentially affected by caloric restriction / high-density husbandry. In juvenile fish, scale formation is prioritized over somatic growth, while in sexually mature adults, female reproduction is prioritized over somatic growth, and somatic growth over fat storage. Our data will serve as a template for future functional studies to dissect the neuroendocrine regulators of energy homeostasis

  18. Oestrogen and insulin-like growth factors during the reproduction and growth of the tilapia Oreochromis niloticus and their interactions.

    PubMed

    Baroiller, Jean-François; D'Cotta, Helena; Shved, Natalia; Berishvili, Giorgi; Toguyeni, Aboubacar; Fostier, Alexis; Eppler, Elisabeth; Reinecke, Manfred

    2014-09-01

    Oestrogens and insulin-like growth factors (Igfs) play both a central role in the regulation of reproduction and growth and can interact especially in species showing a clear-cut sex-linked growth dimorphism (SGD) like in tilapia. Aromatase is essential in ovarian differentiation and oogenesis since it controls oestrogen synthesis. During tilapia sex differentiation, aromatase cyp19a1a expression increases from 9 days post-fertilization (dpf), resulting in high oestradiol level. High temperature, exogenous androgens or aromatase inhibitors override genetic sex differentiation inducing testes development through the suppression of cyp19a1a gene expression and aromatase activity. Supplementation with 17ß-oestradiol (E2) of gonadectomized juveniles induced a sustained and higher E2 plasma level than in intact or gonadectomized controls and both sexes showed reduced growth. Juvenile and mature females treated with the aromatase inhibitor 1,4,6-androstatriene-3,17-dione had 19% lower E2 plasma level compared to controls and they showed a 32% increased growth after 28 days of treatment. Altogether, these data suggest that E2 inhibits female growth leading to the SGD. Regarding Igf-1, mRNA and peptide appeared in liver at ∼ 4 dpf and then in organs involved in growth and metabolism, indicating a role in early growth, metabolism and organogenesis. Gonad igf-1 showed an early expression and the peptide could be detected at ∼ 7 dpf in somatic cells. It appeared in germ cells at the onset of ovarian (29 dpf) and testicular (52 dpf) meiosis. In testis, Igf-1 together with steroids may regulate spermatogenesis whereas in ovary it participates in steroidogenesis regulation. Igf-1 and Igf-2 promote proliferation of follicular cells and oocyte maturation. Igf-3 expression is gonad specific and localized in the ovarian granulosa or testicular interstitial cells. In developing gonads igf-3 is up-regulated in males but down-regulated in females. In contrast, bream Gh injections

  19. Effects of nitrogen form on growth, CO₂ assimilation, chlorophyll fluorescence, and photosynthetic electron allocation in cucumber and rice plants.

    PubMed

    Zhou, Yan-hong; Zhang, Yi-li; Wang, Xue-min; Cui, Jin-xia; Xia, Xiao-jian; Shi, Kai; Yu, Jing-quan

    2011-02-01

    Cucumber and rice plants with varying ammonium (NH(4)(+)) sensitivities were used to examine the effects of different nitrogen (N) sources on gas exchange, chlorophyll (Chl) fluorescence quenching, and photosynthetic electron allocation. Compared to nitrate (NO(3)(-))-grown plants, cucumber plants grown under NH(4)(+)-nutrition showed decreased plant growth, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide (CO(2)) level, transpiration rate, maximum photochemical efficiency of photosystem II, and O(2)-independent alternative electron flux, and increased O(2)-dependent alternative electron flux. However, the N source had little effect on gas exchange, Chl a fluorescence parameters, and photosynthetic electron allocation in rice plants, except that NH(4)(+)-grown plants had a higher O(2)-independent alternative electron flux than NO(3)(-)-grown plants. NO(3)(-) reduction activity was rarely detected in leaves of NH(4)(+)-grown cucumber plants, but was high in NH(4)(+)-grown rice plants. These results demonstrate that significant amounts of photosynthetic electron transport were coupled to NO(3)(-) assimilation, an effect more significant in NO(3)(-)-grown plants than in NH(4)(+)-grown plants. Meanwhile, NH(4)(+)-tolerant plants exhibited a higher demand for the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) for NO(3)(-) reduction, regardless of the N form supplied, while NH(4)(+)-sensitive plants had a high water-water cycle activity when NH(4)(+) was supplied as the sole N source.

  20. Arabidopsis coordinates the diurnal regulation of carbon allocation and growth across a wide range of photoperiods.

    PubMed

    Sulpice, Ronan; Flis, Anna; Ivakov, Alexander A; Apelt, Federico; Krohn, Nicole; Encke, Beatrice; Abel, Christin; Feil, Regina; Lunn, John E; Stitt, Mark

    2014-01-01

    In short photoperiods, plants accumulate starch more rapidly in the light and degrade it more slowly at night, ensuring that their starch reserves last until dawn. To investigate the accompanying changes in the timing of growth, Arabidopsis was grown in a range of photoperiods and analyzed for rosette biomass, photosynthesis, respiration, ribosome abundance, polysome loading, starch, and over 40 metabolites at dawn and dusk. The data set was used to model growth rates in the daytime and night, and to identify metabolites that correlate with growth. Modeled growth rates and polysome loading were high in the daytime and at night in long photoperiods, but decreased at night in short photoperiods. Ribosome abundance was similar in all photoperiods. It is discussed how the amount of starch accumulated in the light period, the length of the night, and maintenance costs interact to constrain growth at night in short photoperiods, and alter the strategy for optimizing ribosome use. Significant correlations were found in the daytime and the night between growth rates and the levels of the sugar-signal trehalose 6-phosphate and the amino acid biosynthesis intermediate shikimate, identifying these metabolites as hubs in a network that coordinates growth with diurnal changes in the carbon supply.

  1. The dynamic of annual carbon allocation to wood in European forests is consistent with a combined source-sink limitation of growth: implications for modelling

    NASA Astrophysics Data System (ADS)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrêne, E.; François, C.; Soudani, K.; Ourcival, J. M.; Delpierre, N.

    2015-02-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will condition the response of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study is to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in five tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex, Quercus robur and Picea abies). Combining field measurements and process-based simulations at 49 sites (931 site-years), we assessed the stand biomass growth dependences at both inter-site and inter-annual scales. Specifically, the relative influence of forest C balance (source control), direct environmental control (water and temperature controls of sink activity) and allocation adjustments related to age, past climate conditions, competition intensity and soil nutrient availability on growth were quantified. The inter-site variability in stand C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual stand woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. We provide an evaluation of the spatio-temporal dynamics of annual carbon allocation to wood in European forests. Our study supports the premise that European forest growth is under a complex control including both source and sink limitations. The relative influences of the different growth drivers strongly vary across years and spatial ecological gradients. We suggest a

  2. Birth Weight, Intrauterine Growth Retardation and Fetal Susceptibility to Porcine Reproductive and Respiratory Syndrome Virus

    PubMed Central

    Ladinig, Andrea; Foxcroft, George; Ashley, Carolyn; Lunney, Joan K.; Plastow, Graham; Harding, John C. S.

    2014-01-01

    The severity of porcine reproductive and respiratory syndrome was compared in pregnant gilts originating from high and low birth weight litters. One-hundred and eleven pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus on gestation day 85 (±1) were necropsied along with their fetuses 21 days later. Ovulation rates and litter size did not differ between groups, but fetuses from low birth weight gilts were shorter, lighter and demonstrated evidence of asymmetric growth with large brain:organ weight ratios (i.e. brain sparing). The number of intrauterine growth retarded fetuses, defined by brain:organ weight ratios greater than 1 standard deviation from the mean, was significantly greater in low, compared to high, birth weight gilts. Although γδ T cells significantly decreased over time in high compared to low birth weight gilts, viral load in serum and tissues, gilt serum cytokine levels, and litter outcome, including the percent dead fetuses per litter, did not differ by birth weight group. Thus, this study provided no substantive evidence that the severity of porcine reproductive and respiratory syndrome is affected by dam birth weight. However, intrauterine growth retarded fetuses had lower viral loads in both fetal thymus and in endometrium adjacent to the umbilical stump. Crown rump length did not significantly differ between fetuses that survived and those that died at least one week prior to termination. Taken together, this study clearly demonstrates that birth weight is a transgenerational trait in pigs, and provides evidence that larger fetuses are more susceptible to transplacental PRRSv infection. PMID:25275491

  3. Evaluating the fitness of human lysozyme transgenic dairy goats: growth and reproductive traits.

    PubMed

    Jackson, Kathryn A; Berg, Jolene M; Murray, James D; Maga, Elizabeth A

    2010-12-01

    While there are many reports in the literature describing the attributes of specific applications of transgenic animals for agriculture, there are relatively few studies focusing on the fitness of the transgenic animals themselves. This work was designed to gather information on genetically modified food animals to determine if the presence of a transgene can impact general animal production traits. More specifically, we used a line of transgenic dairy goats expressing human lysozyme in their mammary gland to evaluate the reproductive fitness and growth and development of these animals compared to their non-transgenic counterparts and the impact of consuming a transgenic food product, lysozyme-containing milk. In males, none of the parameters of semen quality, including semen volume and concentration, total sperm per ejaculate, sperm morphology, viability and motility, were significantly different between transgenic bucks and non-transgenic full-sib controls. Likewise, transgenic females of this line did not significantly differ in the reproductive traits of gestation length and litter size compared to their non-transgenic counterparts. To evaluate growth, transgenic and non-transgenic kid goats received colostrum and milk from either transgenic or non-transgenic does from birth until weaning. Neither the presence of the transgene nor the consumption of milk from transgenic animals significantly affected birth weight, weaning weight, overall gain and post-wean gain. These results indicate that the analyzed reproductive and growth traits were not regularly or substantially impacted by the presence or expression of the transgene. The evaluation of these general parameters is an important aspect of defining the safety of applying transgenic technology to animal agriculture.

  4. Creep-feeding to stimulate metabolic imprinting in nursing beef heifers: impacts on heifer growth, reproductive and physiological variables.

    PubMed

    Reis, M M; Cooke, R F; Cappellozza, B I; Marques, R S; Guarnieri Filho, T A; Rodrigues, M C; Bradley, J S; Mueller, C J; Keisler, D H; Johnson, S E; Bohnert, D W

    2015-09-01

    This experiment compared growth, physiological, and reproductive responses of beef heifers with (MI) or without (CON) access to a creep-feeder, as a manner to stimulate metabolic imprinting while nursing their dams. On day 0, 60 Angus × Hereford heifers were ranked by BW and age (140 ± 3 kg and 68±3 days), and assigned to pairs so all ranking criteria were similar between heifers within each pair. On day 1, pairs were randomly assigned to MI (n=15) or CON (n=15). From day 1 to 51, MI pairs and their dams were allocated to 15 drylot pens where heifers had ad libitum access to a corn-based supplement through a creep-feeder. The CON pairs and their dams were maintained in an adjacent single drylot pen. From day 52 to 111, treatments were managed as a single group on a semiarid range pasture. On day 111, heifers were weaned and allocated to two pastures (one pasture/treatment), receiving hay and a corn-based concentrate until day 326. Heifer BW was recorded before and at the end of the creep-feeding period (day 1 to 51), and on days 112 and 326. On days 0, 51, 111, 187, 261, and 325, jugular blood was collected and real-time ultrasonography for longissimus muscle depth and backfat thickness assessment was performed. Blood was also collected every 10 days from days 113 to 323 for puberty evaluation via plasma progesterone. Liver and subcutaneous fat biopsies were performed on days 51, 111, 261 and 325. Average daily gain was greater (P<0.01) for MI than CON from day 1 to 51, tended (P=0.09) to be greater for CON than MI from day 112 to 326, while BW on day 326 was similar between treatments. On day 51, MI had greater (P ⩽ 0.01) plasma IGF-I and glucose concentrations, as well as mRNA expression of hepatic pyruvate carboxylase and adipose fatty acid synthase than CON. On days 261 and 325, plasma insulin concentrations were greater (P ⩽ 0.03) in CON than MI. Mean mRNA expression of hepatic IGF-I and adipose peroxisome proliferator-activated receptor gamma were

  5. C4 photosynthesis boosts growth by altering physiology, allocation and size.

    PubMed

    Atkinson, Rebecca R L; Mockford, Emily J; Bennett, Christopher; Christin, Pascal-Antoine; Spriggs, Elizabeth L; Freckleton, Robert P; Thompson, Ken; Rees, Mark; Osborne, Colin P

    2016-01-01

    C4 photosynthesis is a complex set of leaf anatomical and biochemical adaptations that have evolved more than 60 times to boost carbon uptake compared with the ancestral C3 photosynthetic type(1-3). Although C4 photosynthesis has the potential to drive faster growth rates(4,5), experiments directly comparing C3 and C4 plants have not shown consistent effects(1,6,7). This is problematic because differential growth is a crucial element of ecological theory(8,9) explaining C4 savannah responses to global change(10,11), and research to increase C3 crop productivity by introducing C4 photosynthesis(12). Here, we resolve this long-standing issue by comparing growth across 382 grass species, accounting for ecological diversity and evolutionary history. C4 photosynthesis causes a 19-88% daily growth enhancement. Unexpectedly, during the critical seedling establishment stage, this enhancement is driven largely by a high ratio of leaf area to mass, rather than fast growth per unit leaf area. C4 leaves have less dense tissues, allowing more leaves to be produced for the same carbon cost. Consequently, C4 plants invest more in roots than C3 species. Our data demonstrate a general suite of functional trait divergences between C3 and C4 species, which simultaneously drive faster growth and greater investment in water and nutrient acquisition, with important ecological and agronomic implications. PMID:27243645

  6. Reproductive performance of alternative male phenotypes of growth hormone transgenic Atlantic salmon (Salmo salar).

    PubMed

    Moreau, Darek T R; Conway, Corinne; Fleming, Ian A

    2011-11-01

    Growth hormone (GH) transgenic Atlantic salmon (Salmo salar) is one of the first transgenic animals being considered for commercial farming, yet ecological and genetic concerns remain should they enter the wild and interact reproductively with wild fish. Here, we provide the first empirical data reporting on the breeding performance of GH transgenic Atlantic salmon males, including that of an alternative male reproductive phenotype (i.e. small, precocially mature parr), in pair-wise competitive trials within a naturalised stream mesocosm. Wild anadromous (i.e. large, migratory) males outperformed captively reared transgenic counterparts in terms of nest fidelity, quivering frequency and spawn participation. Similarly, despite displaying less aggression, captively reared nontransgenic mature parr were superior competitors to their transgenic counterparts in terms of nest fidelity and spawn participation. Moreover, nontransgenic parr had higher overall fertilisation success than transgenic parr, and their offspring were represented in more spawning trials. Although transgenic males displayed reduced breeding performance relative to nontransgenics, both male reproductive phenotypes demonstrated the ability to participate in natural spawning events and thus have the potential to contribute genes to subsequent generations.

  7. Reproductive performance of alternative male phenotypes of growth hormone transgenic Atlantic salmon (Salmo salar)

    PubMed Central

    Moreau, Darek T R; Conway, Corinne; Fleming, Ian A

    2011-01-01

    Growth hormone (GH) transgenic Atlantic salmon (Salmo salar) is one of the first transgenic animals being considered for commercial farming, yet ecological and genetic concerns remain should they enter the wild and interact reproductively with wild fish. Here, we provide the first empirical data reporting on the breeding performance of GH transgenic Atlantic salmon males, including that of an alternative male reproductive phenotype (i.e. small, precocially mature parr), in pair-wise competitive trials within a naturalised stream mesocosm. Wild anadromous (i.e. large, migratory) males outperformed captively reared transgenic counterparts in terms of nest fidelity, quivering frequency and spawn participation. Similarly, despite displaying less aggression, captively reared nontransgenic mature parr were superior competitors to their transgenic counterparts in terms of nest fidelity and spawn participation. Moreover, nontransgenic parr had higher overall fertilisation success than transgenic parr, and their offspring were represented in more spawning trials. Although transgenic males displayed reduced breeding performance relative to nontransgenics, both male reproductive phenotypes demonstrated the ability to participate in natural spawning events and thus have the potential to contribute genes to subsequent generations. PMID:25568019

  8. Allocation trade-off under climate warming in experimental amphibian populations

    PubMed Central

    Gao, Xu; Jin, Changnan; Camargo, Arley

    2015-01-01

    Climate change could either directly or indirectly cause population declines via altered temperature, rainfall regimes, food availability or phenological responses. However few studies have focused on allocation trade-offs between growth and reproduction under marginal resources, such as food scarce that may be caused by climate warming. Such critical changes may have an unpredicted impact on amphibian life-history parameters and even population dynamics. Here, we report an allocation strategy of adult anuran individuals involving a reproductive stage under experimental warming. Using outdoor mesocosm experiments we simulated a warming scenario likely to occur at the end of this century. We examined the effects of temperature (ambient vs. pre-/post-hibernation warming) and food availability (normal vs. low) on reproduction and growth parameters of pond frogs (Pelophylax nigromaculatus). We found that temperature was the major factor influencing reproductive time of female pond frogs, which showed a significant advancing under post-hibernation warming treatment. While feeding rate was the major factor influencing reproductive status of females, clutch size, and variation of body size for females, showed significant positive correlations between feeding rate and reproductive status, clutch size, or variation of body size. Our results suggested that reproduction and body size of amphibians might be modulated by climate warming or food availability variation. We believe this study provides some new evidence on allocation strategies suggesting that amphibians could adjust their reproductive output to cope with climate warming. PMID:26500832

  9. Allocation trade-off under climate warming in experimental amphibian populations.

    PubMed

    Gao, Xu; Jin, Changnan; Camargo, Arley; Li, Yiming

    2015-01-01

    Climate change could either directly or indirectly cause population declines via altered temperature, rainfall regimes, food availability or phenological responses. However few studies have focused on allocation trade-offs between growth and reproduction under marginal resources, such as food scarce that may be caused by climate warming. Such critical changes may have an unpredicted impact on amphibian life-history parameters and even population dynamics. Here, we report an allocation strategy of adult anuran individuals involving a reproductive stage under experimental warming. Using outdoor mesocosm experiments we simulated a warming scenario likely to occur at the end of this century. We examined the effects of temperature (ambient vs. pre-/post-hibernation warming) and food availability (normal vs. low) on reproduction and growth parameters of pond frogs (Pelophylax nigromaculatus). We found that temperature was the major factor influencing reproductive time of female pond frogs, which showed a significant advancing under post-hibernation warming treatment. While feeding rate was the major factor influencing reproductive status of females, clutch size, and variation of body size for females, showed significant positive correlations between feeding rate and reproductive status, clutch size, or variation of body size. Our results suggested that reproduction and body size of amphibians might be modulated by climate warming or food availability variation. We believe this study provides some new evidence on allocation strategies suggesting that amphibians could adjust their reproductive output to cope with climate warming. PMID:26500832

  10. Effects of sap-feeding insect herbivores on growth and reproduction of woody plants: a meta-analysis of experimental studies.

    PubMed

    Zvereva, Elena L; Lanta, Vojtech; Kozlov, Mikhail V

    2010-08-01

    The majority of generalisations concerning plant responses to herbivory are based on studies of natural or simulated defoliation. However, effects caused by insects feeding on plant sap are likely to differ from the effects of folivory. We assessed the general patterns and sources of variation in the effects of sap feeding on growth, photosynthesis, and reproduction of woody plants through a meta-analysis of 272 effect sizes calculated from 52 papers. Sap-feeders significantly reduced growth (-29%), reproduction (-17%), and photosynthesis (-27%); seedlings suffered more than saplings and mature trees. Deciduous and evergreen woody plants did not differ in their abilities to tolerate damage imposed by sap-feeders. Different plant parts, in particular below- and above-ground organs, responded similarly to damage, indicating that sap-feeders did not change the resource allocation in plants. The strongest effects were caused by mesophyll and phloem feeders, and the weakest by xylem feeders. Generalist sap-feeders reduced plant performance to a greater extent than did specialists. Methodology substantially influenced the outcomes of the primary studies; experiments conducted in greenhouses yielded stronger negative effects than field experiments; shorter (<12 months) experiments showed bigger growth reduction in response to sap feeding than longer experiments; natural levels of herbivory caused weaker effects than infestation of experimental plants by sap-feeders. Studies conducted at higher temperatures yielded stronger detrimental effects of sap-feeders on their hosts. We conclude that sap-feeders impose a more severe overall negative impact on plant performance than do defoliators, mostly due to the lower abilities of woody plants to compensate for sap-feeders' damage in terms of both growth and photosynthesis.

  11. Patterns of reproduction in slave-making ants

    PubMed Central

    Herbers, J. M.; Stuart, R. J.

    1998-01-01

    Sex ratios in slave-making ants have been posed as important test cases for the hypothesis that eusociality evolved via kin selection in insects. Trivers and Hare proposed that sex ratios in slave-makers should reflect the queen's interests whereas sex ratios in free-living host ants should reflect the workers' interests. We analyse patterns of allocation to males versus females, as well as allocation to growth versus reproduction for slave-making ants in the tribe Formicoxenini. We find little support for the hypothesis of exclusive queen control; instead, our results implicate queen–worker conflict in slave-making ants, both over male allocation ratios and over allocation to growth versus reproduction.

  12. Simulation of wheat growth and development based on organ-level photosynthesis and assimilate allocation.

    PubMed

    Evers, J B; Vos, J; Yin, X; Romero, P; van der Putten, P E L; Struik, P C

    2010-05-01

    Intimate relationships exist between form and function of plants, determining many processes governing their growth and development. However, in most crop simulation models that have been created to simulate plant growth and, for example, predict biomass production, plant structure has been neglected. In this study, a detailed simulation model of growth and development of spring wheat (Triticum aestivum) is presented, which integrates degree of tillering and canopy architecture with organ-level light interception, photosynthesis, and dry-matter partitioning. An existing spatially explicit 3D architectural model of wheat development was extended with routines for organ-level microclimate, photosynthesis, assimilate distribution within the plant structure according to organ demands, and organ growth and development. Outgrowth of tiller buds was made dependent on the ratio between assimilate supply and demand of the plants. Organ-level photosynthesis, biomass production, and bud outgrowth were simulated satisfactorily. However, to improve crop simulation results more efforts are needed mechanistically to model other major plant physiological processes such as nitrogen uptake and distribution, tiller death, and leaf senescence. Nevertheless, the work presented here is a significant step forwards towards a mechanistic functional-structural plant model, which integrates plant architecture with key plant processes.

  13. Simulation of wheat growth and development based on organ-level photosynthesis and assimilate allocation.

    PubMed

    Evers, J B; Vos, J; Yin, X; Romero, P; van der Putten, P E L; Struik, P C

    2010-05-01

    Intimate relationships exist between form and function of plants, determining many processes governing their growth and development. However, in most crop simulation models that have been created to simulate plant growth and, for example, predict biomass production, plant structure has been neglected. In this study, a detailed simulation model of growth and development of spring wheat (Triticum aestivum) is presented, which integrates degree of tillering and canopy architecture with organ-level light interception, photosynthesis, and dry-matter partitioning. An existing spatially explicit 3D architectural model of wheat development was extended with routines for organ-level microclimate, photosynthesis, assimilate distribution within the plant structure according to organ demands, and organ growth and development. Outgrowth of tiller buds was made dependent on the ratio between assimilate supply and demand of the plants. Organ-level photosynthesis, biomass production, and bud outgrowth were simulated satisfactorily. However, to improve crop simulation results more efforts are needed mechanistically to model other major plant physiological processes such as nitrogen uptake and distribution, tiller death, and leaf senescence. Nevertheless, the work presented here is a significant step forwards towards a mechanistic functional-structural plant model, which integrates plant architecture with key plant processes. PMID:20231326

  14. Faster reproductive rates trade off against offspring growth in wild chimpanzees.

    PubMed

    Emery Thompson, Melissa; Muller, Martin N; Sabbi, Kris; Machanda, Zarin P; Otali, Emily; Wrangham, Richard W

    2016-07-12

    Life history theory predicts a trade-off between offspring quality and quantity. Among large-bodied mammals, prolonged lactation and infant dependence suggest particularly strong potential for a quality-quantity trade-off to exist. Humans are one of the only such species to have been examined, providing mixed evidence under a peculiar set of circumstances, including extensive nutritional provisioning by nonmothers and extrasomatic wealth transmission. Here, we examine trade-offs between reproductive rate and one aspect of offspring quality (body size) in wild chimpanzees (Pan troglodytes schweinfurthii), a species with long periods of infant dependence and little direct provisioning. Juvenile lean body mass, estimated using urinary creatinine excretion, was positively associated with the interval to the next sibling's birth. These effects persisted into adolescence and were not moderated by maternal identity. Maternal depletion could not explain poor offspring growth, as older mothers had larger offspring, and low maternal energy balance during lactation predicted larger, not smaller, juvenile size. Instead, our data suggest that offspring growth suffers when mothers wean early to invest in new reproductive efforts. These findings indicate that chimpanzee mothers with the resources to do so prioritize production of new offspring over prolonged investment in current offspring. PMID:27354523

  15. Epidemic growth rate and household reproduction number in communities of households, schools and workplaces.

    PubMed

    Pellis, Lorenzo; Ferguson, Neil M; Fraser, Christophe

    2011-10-01

    In this paper we present a novel and coherent modelling framework for the characterisation of the real-time growth rate in SIR models of epidemic spread in populations with social structures of increasing complexity. Known results about homogeneous mixing and multitype models are included in the framework, which is then extended to models with households and models with households and schools/workplaces. Efficient methods for the exact computation of the real-time growth rate are presented for the standard SIR model with constant infection and recovery rates (Markovian case). Approximate methods are described for a large class of models with time-varying infection rates (non-Markovian case). The quality of the approximation is assessed via comparison with results from individual-based stochastic simulations. The methodology is then applied to the case of influenza in models with households and schools/workplaces, to provide an estimate of a household-to-household reproduction number and thus asses the effort required to prevent an outbreak by targeting control policies at the level of households. The results highlight the risk of underestimating such effort when the additional presence of schools/workplaces is neglected. Our framework increases the applicability of models of epidemic spread in socially structured population by linking earlier theoretical results, mainly focused on time-independent key epidemiological parameters (e.g. reproduction numbers, critical vaccination coverage, epidemic final size) to new results on the epidemic dynamics. PMID:21120484

  16. Faster reproductive rates trade off against offspring growth in wild chimpanzees.

    PubMed

    Emery Thompson, Melissa; Muller, Martin N; Sabbi, Kris; Machanda, Zarin P; Otali, Emily; Wrangham, Richard W

    2016-07-12

    Life history theory predicts a trade-off between offspring quality and quantity. Among large-bodied mammals, prolonged lactation and infant dependence suggest particularly strong potential for a quality-quantity trade-off to exist. Humans are one of the only such species to have been examined, providing mixed evidence under a peculiar set of circumstances, including extensive nutritional provisioning by nonmothers and extrasomatic wealth transmission. Here, we examine trade-offs between reproductive rate and one aspect of offspring quality (body size) in wild chimpanzees (Pan troglodytes schweinfurthii), a species with long periods of infant dependence and little direct provisioning. Juvenile lean body mass, estimated using urinary creatinine excretion, was positively associated with the interval to the next sibling's birth. These effects persisted into adolescence and were not moderated by maternal identity. Maternal depletion could not explain poor offspring growth, as older mothers had larger offspring, and low maternal energy balance during lactation predicted larger, not smaller, juvenile size. Instead, our data suggest that offspring growth suffers when mothers wean early to invest in new reproductive efforts. These findings indicate that chimpanzee mothers with the resources to do so prioritize production of new offspring over prolonged investment in current offspring.

  17. Appendicularian ecophysiology. II. Modeling nutrition, metabolism, growth and reproduction of the appendicularian Oikopleura dioica

    NASA Astrophysics Data System (ADS)

    Lombard, Fabien; Sciandra, Antoine; Gorsky, Gabriel

    2009-11-01

    A model has been developed to simulate the growth of an individual appendicularian ( Oikopleura dioica) from egg to spawning. This model uses a new set of experimental data presented in a companion paper in this volume and estimates growth rates and generation times as well as clearance rates, house and fecal pellet production and reproductive capacity at different temperatures and food concentrations. According to the model outputs, the weight of a single house represents 11.5% of the individual's total weight, a lower value than previously estimated. The relative weight of one fecal pellet varies as a function of food concentration. The model also confirms that the minimum food concentration for growth is about 20-30 µg C l - 1 and that growth is maximal for a 100 µg C l - 1 feeding concentration. The limits of the growth optimum in relation to food concentration and temperature can be considered as a first description of the fundamental ecological niche of appendicularians. This model can be used both for predicting (1) the impact of in situ observed populations on the pico- and nanoseston and (2) the production of large aggregates. These two pieces of information are often needed for large-scale biogeochemical models.

  18. Carbon allocation, source-sink relations and plant growth: do we need to revise our carbon centric concepts?

    NASA Astrophysics Data System (ADS)

    Körner, Christian

    2014-05-01

    Since the discovery that plants 'eat air' 215 years ago, carbon supply was considered the largely unquestioned top driver of plant growth. The ease at which CO2 uptake (C source activity) can be measured, and the elegant algorithms that describe the responses of photosynthesis to light, temperature and CO2 concentration, explain why carbon driven growth and productivity became the starting point of all process based vegetation models. Most of these models, nowadays adopt other environmental drivers, such as nutrient availability, as modulating co-controls, but the carbon priority is retained. Yet, if we believe in the basic rules of stoichometry of all life, there is an inevitable need of 25-30 elements other then carbon, oxygen and hydrogen to build a healthy plant body. Plants compete for most of these elements, and their availability (except for N) is finite per unit land area. Hence, by pure plausibility, it is a highly unlikely situation that carbon plays the rate limiting role of growth under natural conditions, except in deep shade or on exceptionally fertile soils. Furthermore, water shortage and low temperature, both act directly upon tissue formation (meristems) long before photosynthetic limitations come into play. Hence, plants will incorporate C only to the extent other environmental drivers permit. In the case of nutrients and mature ecosystems, this sink control of plant growth may be masked in the short term by a tight, almost closed nutrient cycle or by widening the C to other element ratio. Because source and sink activity must match in the long term, it is not possible to identify the hierarchy of growth controls without manipulating the environment. Dry matter allocation to C rich structures and reserves may provide some stoichimetric leeway or periodic escapes from the more fundamental, long-term environmental controls of growth and productivity. I will explain why carbon centric explanations of growth are limited or arrive at plausible answers

  19. Effects of lighting and air movement on temperatures in reproductive organs of plants in a closed plant growth facility

    NASA Astrophysics Data System (ADS)

    Kitaya, Y.; Hirai, H.

    Temperature increases in plant reproductive organs such as anthers and stigmas could cause fertility impediments and thus produce sterile seeds under artificial lighting conditions without adequately controlled environments in closed plant growth facilities. There is a possibility such a situation could occur in Bioregenerative Life Support Systems under microgravity conditions in space because there will be little natural convective or thermal mixing. This study was conducted to determine the temperature of the plant reproductive organs as affected by illumination and air movement under normal gravitational forces on the earth and to make an estimation of the temperature increase in reproductive organs in closed plant growth facilities under microgravity in space. Thermal images of reproductive organs of rice and strawberry were captured using infrared thermography at air temperatures of 10 11 °C. Compared to the air temperature, temperatures of petals, stigmas and anthers of strawberry increased by 24, 22 and 14 °C, respectively, after 5 min of lighting at an irradiance of 160 W m-2 from incandescent lamps. Temperatures of reproductive organs and leaves of strawberry were significantly higher than those of rice. The temperatures of petals, stigmas, anthers and leaves of strawberry decreased by 13, 12, 13 and 14 °C, respectively, when the air velocity was increased from 0.1 to 1.0 ms-1. These results show that air movement is necessary to reduce the temperatures of plant reproductive organs in plant growth facilities.

  20. Herbivore-mediated ecological costs of reproduction shape the life history of an iteroparous plant.

    PubMed

    Miller, Tom E X; Tenhumberg, Brigitte; Louda, Svata M

    2008-02-01

    Plant reproduction yields immediate fitness benefits but can be costly in terms of survival, growth, and future fecundity. Life-history theory posits that reproductive strategies are shaped by trade-offs between current and future fitness that result from these direct costs of reproduction. Plant reproduction may also incur indirect ecological costs if it increases susceptibility to herbivores. Yet ecological costs of reproduction have received little empirical attention and remain poorly integrated into life-history theory. Here, we provide evidence for herbivore-mediated ecological costs of reproduction, and we develop theory to examine how these costs influence plant life-history strategies. Field experiments with an iteroparous cactus (Opuntia imbricata) indicated that greater reproductive effort (proportion of meristems allocated to reproduction) led to greater attack by a cactus-feeding insect (Narnia pallidicornis) and that damage by this herbivore reduced reproductive success. A dynamic programming model predicted strongly divergent optimal reproductive strategies when ecological costs were included, compared with when these costs were ignored. Meristem allocation by cacti in the field matched the optimal strategy expected under ecological costs of reproduction. The results indicate that plant reproductive allocation can strongly influence the intensity of interactions with herbivores and that associated ecological costs can play an important selective role in the evolution of plant life histories.

  1. Age, growth, and reproductive biology of three catostomids from the Apalachicola River, Florida

    USGS Publications Warehouse

    Grabowski, Timothy B.; Young, S.P.; Isely, J.J.; Ely, Patrick C.

    2012-01-01

    Riverine catostomids can show a wide range of interspecific variation in life-history characteristics. Understanding these differences is an important consideration in evaluating the sensitivity of these fishes to disturbance and in formulating effective conservation strategies, particularly when dealing with an assemblage consisting of multiple species within a watershed. We collected Apalachicola redhorse Moxostoma n. sp. cf. poecilurum (n = 125), spotted sucker Minytrema melanops (n = 94), and quillback Carpiodes cyprinus (n = 94) to determine age, growth, and reproductive biology of spawning catostomids in the Apalachicola River, Florida, during 2007. Quillback was the smallest in total length at age; longest-lived; most fecund; and produced the smallest eggs. Apalachicola redhorse was the largest in body size; had an intermediate life span; and produced the fewest yet largest eggs. Spotted sucker was more similar to Apalachicola redhorse in most characteristics. Growth during ages 1-3 in all three species seemed to be negatively related to the proportion of observations of extreme flow, both high (Q90) and low (Q10), per year and a positive response in growth rate to high flows (>Q75 but < Q90). However, Apalachicola redhorse and spotted sucker growth was more sensitive to flow conditions than that of quillback. Our results suggest the life histories and ecological response of Apalachicola River catostomids to flow regulation are important components for developing strategies that incorporate the needs of these fishery resources into an ecosystem-based management approach.

  2. Herbivores Influence the Growth, Reproduction, and Morphology of a Widespread Arctic Willow

    PubMed Central

    Christie, Katie S.; Ruess, Roger W.; Lindberg, Mark S.; Mulder, Christa P.

    2014-01-01

    Shrubs have expanded in Arctic ecosystems over the past century, resulting in significant changes to albedo, ecosystem function, and plant community composition. Willow and rock ptarmigan (Lagopus lagopus, L. muta) and moose (Alces alces) extensively browse Arctic shrubs, and may influence their architecture, growth, and reproduction. Furthermore, these herbivores may alter forage plants in such a way as to increase the quantity and accessibility of their own food source. We estimated the effect of winter browsing by ptarmigan and moose on an abundant, early-successional willow (Salix alaxensis) in northern Alaska by comparing browsed to unbrowsed branches. Ptarmigan browsed 82–89% of willows and removed 30–39% of buds, depending on study area and year. Moose browsed 17–44% of willows and browsed 39–55% of shoots. Browsing inhibited apical dominance and activated axillary and adventitious buds to produce new vegetative shoots. Ptarmigan- and moose-browsed willow branches produced twice the volume of shoot growth but significantly fewer catkins the following summer compared with unbrowsed willow branches. Shoots on browsed willows were larger and produced 40–60% more buds compared to unbrowsed shoots. This process of shoot production at basal parts of the branch is the mechanism by which willows develop a highly complex “broomed” architecture after several years of browsing. Broomed willows were shorter and more likely to be re-browsed by ptarmigan, but not moose. Ptarmigan likely benefit from the greater quantity and accessibility of buds on previously browsed willows and may increase the carrying capacity of their own habitat. Despite the observed tolerance of willows to browsing, their vertical growth and reproduction were strongly inhibited by moose and ptarmigan. Browsing by these herbivores therefore needs to be considered in future models of shrub expansion in the Arctic. PMID:25047582

  3. [Effects of NaCl stress on the seedling growth and K(+)- and Na(+) -allocation of four leguminous tree species].

    PubMed

    Mo, Hai-Bo; Yin, Yun-Long; Lu, Zhi-Guo; Wei, Xiu-Jun; Xu, Jian-Hua

    2011-05-01

    Taking the pot-cultured seedlings of four leguminous tree species (Albizia julibrissin, Robinia pseudoacacia, Sophora japonica, and Gleditsia sinensis) as test materials, this paper studied their growth indices, critical salt concentration (C50), and K+ and Na+ allocation under different levels of NaCl stress, aimed to understand the difference of test tree species in salt tolerance. NaCl stress inhibited the seedling growth of the tree species. Under NaCl stress, the dry matter accumulation decreased, while the root/shoot ratio increased, especially for A. julibrissin and G. sinensis. Quadratic regression analysis showed that the C50 of A. julibrissin, R. pseudoacacia, S. japonica, and G. sinensis was 3.0 per thousand, 5.0 per thousand, 4.5 per thousand, and 3.9 per thousand, respectively, i.e., the salt tolerance of the four tree species was in the order of R. pseudoacacia > S. japonica > G. sinensis > A. julibrissin. In the root, stem, and leaf of the four tree species seedlings, the Na+ content increased with the increase of NaCl stress, while the K+ content (except in the root of A. julibrissin) decreased after an initial increase, resulting in a larger difference in the K+/Na+ ratio in the organs. Under the same NaCl stress, the allocation of Na+ in different organs of the four tree species seedlings decreased in the order of root>stem>leaf, while that of K+ differed with tree species and NaCl stress, and leaf was the main storage organ for K+. The K+/Na+ ratio in different organs decreased in the sequence of leaf>stem>root. R. pseudoacacia under NaCl stress accumulated more K+ and less Na+ in stem and leaf, and had higher K+/Na+ ratio in all organs and higher dry mass, being assessed to be more salt-tolerant. In contrast, A. julibrissin under high NaCl stress accumulated more Na+ in stem and leaf, and had a lower K+/Na+ ratio in all organs and lower dry mass, being evaluated to be lesser salt-tolerant. The K+ accumulation in seedling stem and leaf and the Na

  4. Epidermal growth factor binding and receptor distribution in the mouse reproductive tract during development

    SciTech Connect

    Bossert, N.L.; Nelson, K.G.; Ross, K.A.; Takahashi, T.; McLachlan, J.A. )

    1990-11-01

    The ontogeny of the epidermal growth factor (EGF) receptor in the different cell types in the neonatal and immature mouse uterus and vagina was examined. Immunohistochemical examination of prenatal and neonatal reproductive tracts with a polyclonal antibody to the EGF receptor shows immunoreactive EGF receptors as early as Day 13 of gestation. Autoradiographic analysis of tissue sections at 3 to 17 days of age (the day of birth is Day 1) demonstrates that both uterine and vaginal epithelial and stromal cells are capable of binding 125I-labeled EGF. Both the 125I-labeled EGF autoradiography and immunohistochemistry in whole tissue show higher EGF receptor levels in the uterine epithelium than the uterine stroma. The presence of EGF receptors was also confirmed by affinity labeling and Scatchard analysis of isolated uterine cell types at 7 and/or 17 days of age. However, in contrast to the autoradiography and immunohistochemistry data of intact tissue, the affinity labeling and Scatchard data of isolated cells indicate that the uterine stroma contains higher levels of EGF receptor than that of the uterine epithelium. The reason for this discrepancy between the different techniques is, as yet, unknown. Regardless of the differences in the actual numbers of EGF receptors obtained, our data demonstrate that the developing mouse reproductive tract contains immunoreactive EGF receptors that are capable of binding 125I-labeled EGF.

  5. Reproduction and Growth in a Murine Model of Early Life-Onset Inflammatory Bowel Disease

    PubMed Central

    Nagy, Eniko; Rodriguiz, Ramona M.; Wetsel, William C.; MacIver, Nancie J.; Hale, Laura P.

    2016-01-01

    Studies in transgenic murine models have provided insight into the complexity underlying inflammatory bowel disease (IBD), a disease hypothesized to result from an injurious immune response against intestinal microbiota. We recently developed a mouse model of IBD that phenotypically and histologically resembles human childhood-onset ulcerative colitis (UC), using mice that are genetically modified to be deficient in the cytokines TNF and IL-10 (“T/I” mice). Here we report the effects of early life onset of colon inflammation on growth and reproductive performance of T/I mice. T/I dams with colitis often failed to get pregnant or had small litters with pups that failed to thrive. Production was optimized by breeding double homozygous mutant T/I males to females homozygous mutant for TNF deficiency and heterozygous for deficiency of IL-10 (“T/I-het” dams) that were not susceptible to spontaneous colon inflammation. When born to healthy (T/I-het) dams, T/I pups initially gained weight similarly to wild type (WT) pups and to their non-colitis-susceptible T/I-het littermates. However, their growth curves diverged between 8 and 13 weeks, when most T/I mice had developed moderate to severe colitis. The observed growth failure in T/I mice occurred despite a significant increase in their food consumption and in the absence of protein loss in the stool. This was not due to TNF-induced anorexia or altered food consumption due to elevated leptin levels. Metabolic studies demonstrated increased consumption of oxygen and water and increased production of heat and CO2 in T/I mice compared to their T/I-het littermates, without differences in motor activity. Based on the clinical similarities of this early life onset model of IBD in T/I mice to human IBD, these results suggest that mechanisms previously hypothesized to explain growth failure in children with IBD require re-evaluation. The T/I mouse model may be useful for further investigation of such mechanisms and for

  6. Reproduction and Growth in a Murine Model of Early Life-Onset Inflammatory Bowel Disease.

    PubMed

    Nagy, Eniko; Rodriguiz, Ramona M; Wetsel, William C; MacIver, Nancie J; Hale, Laura P

    2016-01-01

    Studies in transgenic murine models have provided insight into the complexity underlying inflammatory bowel disease (IBD), a disease hypothesized to result from an injurious immune response against intestinal microbiota. We recently developed a mouse model of IBD that phenotypically and histologically resembles human childhood-onset ulcerative colitis (UC), using mice that are genetically modified to be deficient in the cytokines TNF and IL-10 ("T/I" mice). Here we report the effects of early life onset of colon inflammation on growth and reproductive performance of T/I mice. T/I dams with colitis often failed to get pregnant or had small litters with pups that failed to thrive. Production was optimized by breeding double homozygous mutant T/I males to females homozygous mutant for TNF deficiency and heterozygous for deficiency of IL-10 ("T/I-het" dams) that were not susceptible to spontaneous colon inflammation. When born to healthy (T/I-het) dams, T/I pups initially gained weight similarly to wild type (WT) pups and to their non-colitis-susceptible T/I-het littermates. However, their growth curves diverged between 8 and 13 weeks, when most T/I mice had developed moderate to severe colitis. The observed growth failure in T/I mice occurred despite a significant increase in their food consumption and in the absence of protein loss in the stool. This was not due to TNF-induced anorexia or altered food consumption due to elevated leptin levels. Metabolic studies demonstrated increased consumption of oxygen and water and increased production of heat and CO2 in T/I mice compared to their T/I-het littermates, without differences in motor activity. Based on the clinical similarities of this early life onset model of IBD in T/I mice to human IBD, these results suggest that mechanisms previously hypothesized to explain growth failure in children with IBD require re-evaluation. The T/I mouse model may be useful for further investigation of such mechanisms and for development

  7. Factors modulating cottongrass seedling growth stimulation to enhanced nitrogen and carbon dioxide: compensatory tradeoffs in leaf dynamics and allocation to meet potassium-limited growth.

    PubMed

    Siegenthaler, Andy; Buttler, Alexandre; Grosvernier, Philippe; Gobat, Jean-Michel; Nilsson, Mats B; Mitchell, Edward A D

    2013-02-01

    Eriophorum vaginatum is a characteristic species of northern peatlands and a keystone plant for cutover bog restoration. Understanding the factors affecting E. vaginatum seedling establishment (i.e. growth dynamics and allocation) under global change has practical implications for the management of abandoned mined bogs and restoration of their C-sequestration function. We studied the responses of leaf dynamics, above- and belowground biomass production of establishing seedlings to elevated CO(2) and N. We hypothesised that nutrient factors such as limitation shifts or dilutions would modulate growth stimulation. Elevated CO(2) did not affect biomass, but increased the number of young leaves in spring (+400 %), and the plant vitality (i.e. number of green leaves/total number of leaves) (+3 %), both of which were negatively correlated to [K(+)] in surface porewater, suggesting a K-limited production of young leaves. Nutrient ratios in green leaves indicated either N and K co-limitation or K limitation. N addition enhanced the number of tillers (+38 %), green leaves (+18 %), aboveground and belowground biomass (+99, +61 %), leaf mass-to-length ratio (+28 %), and reduced the leaf turnover (-32 %). N addition enhanced N availability and decreased [K(+)] in spring surface porewater. Increased tiller and leaf production in July were associated with a doubling in [K(+)] in surface porewater suggesting that under enhanced N production is K driven. Both experiments illustrate the importance of tradeoffs in E. vaginatum growth between: (1) producing tillers and generating new leaves, (2) maintaining adult leaves and initiating new ones, and (3) investing in basal parts (corms) for storage or in root growth for greater K uptake. The K concentration in surface porewater is thus the single most important factor controlling the growth of E. vaginatum seedlings in the regeneration of selected cutover bogs.

  8. 13C and 15N allocations of two alpine species from early and late snowmelt locations reflect their different growth strategies.

    PubMed

    Baptist, Florence; Tcherkez, Guillaume; Aubert, Serge; Pontailler, Jean-Yves; Choler, Philippe; Nogués, Salvador

    2009-01-01

    Intense efforts are currently devoted to disentangling the relationships between plant carbon (C) allocation patterns and soil nitrogen (N) availability because of their consequences for growth and more generally for C sequestration. In cold ecosystems, only a few studies have addressed whole-plant C and/or N allocation along natural elevational or topographical gradients. (12)C/(13)C and (14)N/(15)N isotope techniques have been used to elucidate C and N partitioning in two alpine graminoids characterized by contrasted nutrient economies: a slow-growing species, Kobresia myosuroides (KM), and a fast-growing species, Carex foetida (CF), located in early and late snowmelt habitats, respectively, within the alpine tundra (French Alps). CF allocated higher labelling-related (13)C content belowground and produced more root biomass. Furthermore, assimilates transferred to the roots were preferentially used for growth rather than respiration and tended to favour N reduction in this compartment. Accordingly, this species had higher (15)N uptake efficiency than KM and a higher translocation of reduced (15)N to aboveground organs. These results suggest that at the whole-plant level, there is a compromise between N acquisition/reduction and C allocation patterns for optimized growth.

  9. Excessive dietary selenium to primiparous sows and their offspring. I. Influence on reproduction and growth.

    PubMed

    Poulsen, H D; Danielsen, V; Nielsen, T K; Wolstrup, C

    1989-01-01

    The effect of high dietary selenium (Se) on the reproductive performance, growth and health in pigs was examined. Addition of 0 to 16 mg Se per kg feed to sows and their piglets up to nine weeks of age did not cause any manifest toxic effect. None of the sows died due to the Se treatment. The piglets were all fullborn and showed no macroscopic abnormalities. The treatment did not influence neither the number of liveborn and stillborn piglets in the litter, nor the survival of the piglets until 9 weeks of age. The weight of the whole litter at birth was unaffected by the Se supplementation, while there was a significant difference in body weight of the piglets at 9 weeks of age. The weaned pigs receiving 8 or 16 mg Se per kg feed had a reduced feed intake. As the feed utilization was unaffected by treatment, these pigs had a significantly lower weight at 9 weeks of age.

  10. Nanoplastic affects growth of S. obliquus and reproduction of D. magna.

    PubMed

    Besseling, Ellen; Wang, Bo; Lürling, Miquel; Koelmans, Albert A

    2014-10-21

    The amount of nano- and microplastic in the aquatic environment rises due to the industrial production of plastic and the degradation of plastic into smaller particles. Concerns have been raised about their incorporation into food webs. Little is known about the fate and effects of nanoplastic, especially for the freshwater environment. In this study, effects of nano-polystyrene (nano-PS) on the growth and photosynthesis of the green alga Scenedesmus obliquus and the growth, mortality, neonate production, and malformations of the zooplankter Daphnia magna were assessed. Nano-PS reduced population growth and reduced chlorophyll concentrations in the algae. Exposed Daphnia showed a reduced body size and severe alterations in reproduction. Numbers and body size of neonates were lower, while the number of neonate malformations among neonates rose to 68% of the individuals. These effects of nano-PS were observed between 0.22 and 103 mg nano-PS/L. Malformations occurred from 30 mg of nano-PS/L onward. Such plastic concentrations are much higher than presently reported for marine waters as well as freshwater, but may eventually occur in sediment pore waters. As far as we know, these results are the first to show that direct life history shifts in algae and Daphnia populations may occur as a result of exposure to nanoplastic. PMID:25268330

  11. Growth and Reproduction of Glyphosate-Resistant and Susceptible Populations of Kochia scoparia

    PubMed Central

    Kumar, Vipan; Jha, Prashant

    2015-01-01

    Evolution of glyphosate-resistant kochia is a threat to no-till wheat-fallow and glyphosate-resistant (GR) cropping systems of the US Great Plains. The EPSPS (5-enol-pyruvylshikimate-3-phosphate synthase) gene amplification confers glyphosate resistance in the tested Kochia scoparia (L.) Schrad populations from Montana. Experiments were conducted in spring to fall 2014 (run 1) and summer 2014 to spring 2015 (run 2) to investigate the growth and reproductive traits of the GR vs. glyphosate-susceptible (SUS) populations of K. scoparia and to determine the relationship of EPSPS gene amplification with the level of glyphosate resistance. GR K. scoparia inbred lines (CHES01 and JOP01) exhibited 2 to 14 relative copies of the EPSPS gene compared with the SUS inbred line with only one copy. In the absence of glyphosate, no differences in growth and reproductive parameters were evident between the tested GR and SUS inbred lines, across an intraspecific competition gradient (1 to 170 plants m-2). GR K. scoparia plants with 2 to 4 copies of the EPSPS gene survived the field-use rate (870 g ha-1) of glyphosate, but failed to survive the 4,350 g ha-1 rate of glyphosate (five-times the field-use rate). In contrast, GR plants with 5 to 14 EPSPS gene copies survived the 4,350 g ha-1 of glyphosate. The results from this research indicate that GR K. scoparia with 5 or more EPSPS gene copies will most likely persist in field populations, irrespective of glyphosate selection pressure. PMID:26580558

  12. Anemonefish depletion reduces survival, growth, reproduction and fishery productivity of mutualistic anemone-anemonefish colonies

    NASA Astrophysics Data System (ADS)

    Frisch, Ashley J.; Rizzari, Justin R.; Munkres, Katherine P.; Hobbs, Jean-Paul A.

    2016-06-01

    Intimate knowledge of both partners in a mutualism is necessary to understand the ecology and evolution of each partner, and to manage human impacts that asymmetrically affect one of the partners. Although anemonefishes and their host anemones are iconic mutualists and widely sought by ornamental fisheries, the degree to which anemones depend on anemonefishes, and thus the colony-level effects of collecting anemonefishes, is not well understood. We tracked the size and abundance of anemone Entacmaea quadricolor and anemonefish Amphiprion melanopus colonies for 3 yr after none, some, or all of the resident anemonefish were experimentally removed. Total and partial removal of anemonefish had rapid and sustained negative effects on growth, reproduction and survival of anemones, as well as cascading effects on recruitment and productivity of anemonefish in the remaining colony. As predicted, total removal of anemonefish caused acute declines in size and abundance of anemones, although most anemone colonies (76 %) slowly resumed growth and reproduction after the arrival of anemonefish recruits, which subsequently grew and defended the hosts. Partial removal of anemonefish had similar but typically less severe effects on anemones. Remarkably, the colony-level effects on anemones and anemonefish were proportional to the size and number of anemonefish that were experimentally removed. In particular, anemone survival and anemonefish productivity were highest when one or more adult anemonefish remained in the colony, suggesting that adult fish not only enhanced the protection of anemones, but also increased the recruitment and/or survival of conspecifics. We conclude that the relationship between E. quadricolor and A. melanopus is not only obligate, but also demographically rigid and easily perturbed by anemonefish fisheries. Clearly, these two species must be managed together as a unit and with utmost precaution. To this end, we propose several tangible management actions

  13. Palladium uptake by Pisum sativum: partitioning and effects on growth and reproduction.

    PubMed

    Ronchini, Matteo; Cherchi, Laura; Cantamessa, Simone; Lanfranchi, Marco; Vianelli, Alberto; Gerola, Paolo; Berta, Graziella; Fumagalli, Alessandro

    2015-05-01

    Environmental palladium levels are increasing because of anthropogenic activities. The considerable mobility of the metal, due to solubilisation phenomena, and its known bioavailability may indicate interactions with higher organisms. The aim of the study was to determine the Pd uptake and distribution in the various organs of the higher plant Pisum sativum and the metal-induced effects on its growth and reproduction. P. sativum was grown in vermiculite with a modified Hoagland's solution of nutrients in the presence of Pd at concentrations ranging 0.10-25 mg/L. After 8-10 weeks in a controlled environment room, plants were harvested and dissected to isolate the roots, stems, leaves, pods and peas. The samples were analysed for Pd content using AAS and SEM-EDX. P. sativum absorbed Pd, supplied as K₂PdCl₄, beginning at seed germination and continuing throughout its life. Minimal doses (0.10-1.0 mg Pd/L) severely inhibited pea reproductive processes while showing a peculiar hormetic effect on root development. Pd concentrations ≥1 mg/L induced developmental delay, with late growth resumption, increased leaf biomass (up to 25%) and a 15-20% reduction of root mass. Unsuccessful repeated blossoming efforts led to misshapen pods and no seed production. Photosynthesis was also disrupted. The absorbed Pd (ca. 0.5 % of the supplied metal) was primarily fixed in the root, specifically in the cortex, reaching concentrations up to 200 μg/g. The metal moved through the stem (up to 1 μg/g) to the leaves (2 μg/g) and pods (0.3 μg/g). The presence of Pd in the pea fruits, together with established evidence of environmental Pd accumulation and bioavailability, suggests possible contamination of food plants and propagation in the food chain and must be the cause for concern.

  14. Effect of ruminally undegradable protein from fish meal on growth and reproduction of peripuberal Brahman bulls.

    PubMed

    Rocha, A; Carpena, M; Triplett, B; Forrest, D W; Randel, R D

    1995-04-01

    Thirty-nine Brahman bulls (301.7 +/- 4.1 d; 202.7 +/- 4.7 kg) were allotted to one of two treatments and fed soybean meal (SBM)- or fish meal (FIS)-based supplements and hay to examine the effects of source of protein on growth and reproductive development. The fish meal supplement had 72% ruminally undegradable protein (RUP) and the soybean meal supplement had 47% RUP. Bulls assigned to the FIS treatment had higher (P < .01) total weight gain (81.2 +/- 1.4 vs 71.2 +/- 2.2 kg), higher (P < .01) ADG (.97 +/- .02 vs .85 +/- .03 kg), and better (P < .05) feed:gain ratio (7.6 +/- .1 vs 8.6 +/- .1 feed/BW gain for FIS vs SBM, respectively). Age at first motile spermatozoa was not affected (P > .05) by source of protein (429.9 +/- 9.6 vs 427.2 +/- 9.5 d, for bulls receiving FIS or SBM supplements, respectively). Likewise, age at puberty (473.3 +/- 21.7 d vs 465.9 +/- 12.9 d for bulls receiving FIS and SBM supplements, respectively) was similar for both treatment groups. There were no differences between treatments in scrotal circumference at those stages. At puberty semen quality was similar for bulls receiving FIS or SBM treatments, and no differences existed in LH and testosterone concentrations between treatments. We conclude that fish meal supplement increased growth but did not alter reproductive parameters in Brahman bulls. PMID:7628971

  15. Calcium accumulation and regulation in Daphnia magna: Links with feeding, growth and reproduction.

    PubMed

    Muyssen, Brita T A; De Schamphelaere, Karel A C; Janssen, Colin R

    2009-01-01

    Calcium is involved in a wide variety of biological processes and has an important structural role in crustaceans. The present study aimed at exploring the possible link between Ca body concentrations and the ingestion rate and the role of soft tissue vs. total tissue Ca accumulation in Daphnia magna. D. magna was cultured for 21 days at different water Ca concentrations ranging from 3.4 to 32.5 mg/L. Every week Ca body concentrations (soft and total tissues), ingestion rate, growth, survival and reproduction were measured. Daily, algal food that was not deficient in Ca was supplied. Ca in the soft tissues represented 8 to 26% of the total Ca body concentrations. The ratio Ca in soft tissue/Ca in total tissue was generally not influenced by the Ca exposure concentration but decreased with time, i.e., age (from an average of 0.24 at day 7 to 0.09 at day 21). During week 1, a 54% decrease in Ca body concentrations was observed in daphnids exposed in medium with 3.4 mg/L Ca compared to those exposed to 32.5 mg/L. The concurrent decrease in ingestion rate was 14%. No significant differences among Ca treatments were observed during week 2 for ingestion rate and week 3 for calcium body concentrations. Also, no effects on growth and reproduction were observed, although these were expected at the lowest Ca concentration tested. It is hypothesised that Ca absorption from food in combination with an increased ingestion rate is used to maintain Ca homeostasis under Ca limiting conditions. PMID:18801454

  16. Growth and Reproduction of Glyphosate-Resistant and Susceptible Populations of Kochia scoparia.

    PubMed

    Kumar, Vipan; Jha, Prashant

    2015-01-01

    Evolution of glyphosate-resistant kochia is a threat to no-till wheat-fallow and glyphosate-resistant (GR) cropping systems of the US Great Plains. The EPSPS (5-enol-pyruvylshikimate-3-phosphate synthase) gene amplification confers glyphosate resistance in the tested Kochia scoparia (L.) Schrad populations from Montana. Experiments were conducted in spring to fall 2014 (run 1) and summer 2014 to spring 2015 (run 2) to investigate the growth and reproductive traits of the GR vs. glyphosate-susceptible (SUS) populations of K. scoparia and to determine the relationship of EPSPS gene amplification with the level of glyphosate resistance. GR K. scoparia inbred lines (CHES01 and JOP01) exhibited 2 to 14 relative copies of the EPSPS gene compared with the SUS inbred line with only one copy. In the absence of glyphosate, no differences in growth and reproductive parameters were evident between the tested GR and SUS inbred lines, across an intraspecific competition gradient (1 to 170 plants m-2). GR K. scoparia plants with 2 to 4 copies of the EPSPS gene survived the field-use rate (870 g ha-1) of glyphosate, but failed to survive the 4,350 g ha-1 rate of glyphosate (five-times the field-use rate). In contrast, GR plants with 5 to 14 EPSPS gene copies survived the 4,350 g ha-1 of glyphosate. The results from this research indicate that GR K. scoparia with 5 or more EPSPS gene copies will most likely persist in field populations, irrespective of glyphosate selection pressure.

  17. Growth and Reproduction of Glyphosate-Resistant and Susceptible Populations of Kochia scoparia.

    PubMed

    Kumar, Vipan; Jha, Prashant

    2015-01-01

    Evolution of glyphosate-resistant kochia is a threat to no-till wheat-fallow and glyphosate-resistant (GR) cropping systems of the US Great Plains. The EPSPS (5-enol-pyruvylshikimate-3-phosphate synthase) gene amplification confers glyphosate resistance in the tested Kochia scoparia (L.) Schrad populations from Montana. Experiments were conducted in spring to fall 2014 (run 1) and summer 2014 to spring 2015 (run 2) to investigate the growth and reproductive traits of the GR vs. glyphosate-susceptible (SUS) populations of K. scoparia and to determine the relationship of EPSPS gene amplification with the level of glyphosate resistance. GR K. scoparia inbred lines (CHES01 and JOP01) exhibited 2 to 14 relative copies of the EPSPS gene compared with the SUS inbred line with only one copy. In the absence of glyphosate, no differences in growth and reproductive parameters were evident between the tested GR and SUS inbred lines, across an intraspecific competition gradient (1 to 170 plants m-2). GR K. scoparia plants with 2 to 4 copies of the EPSPS gene survived the field-use rate (870 g ha-1) of glyphosate, but failed to survive the 4,350 g ha-1 rate of glyphosate (five-times the field-use rate). In contrast, GR plants with 5 to 14 EPSPS gene copies survived the 4,350 g ha-1 of glyphosate. The results from this research indicate that GR K. scoparia with 5 or more EPSPS gene copies will most likely persist in field populations, irrespective of glyphosate selection pressure. PMID:26580558

  18. Effects of lithium on growth, maturation, reproduction and gene expression in the nematode Caenorhabditis elegans.

    PubMed

    Inokuchi, Ayako; Yamamoto, Ryoko; Morita, Fumiyo; Takumi, Shota; Matsusaki, Hiromi; Ishibashi, Hiroshi; Tominaga, Nobuaki; Arizono, Koji

    2015-09-01

    Lithium (Li) has been widely used to treat bipolar disorder, and industrial use of Li has been increasing; thus, environmental pollution and ecological impacts of Li have become a concern. This study was conducted to clarify the potential biological effects of LiCl and Li(2)CO(3) on a nematode, Caenorhabditis elegans as a model system for evaluating soil contaminated with Li. Exposure of C. elegans to LiCl and Li(2)CO(3) decreased growth/maturation and reproduction. The lowest observed effect concentrations for growth, maturation and reproduction were 1250, 313 and 10 000 µm, respectively, for LiCl and 750, 750 and 3000 µm, respectively, for Li(2)CO(3). We also investigated the physiological function of LiCl and LiCO(3) in C. elegans using DNA microarray analysis as an eco-toxicogenomic approach. Among approximately 300 unique genes, including metabolic genes, the exposure to 78 µm LiCl downregulated the expression of 36 cytochrome P450, 16 ABC transporter, 10 glutathione S-transferase, 16 lipid metabolism and two vitellogenin genes. On the other hand, exposure to 375 µm Li(2)CO(3) downregulated the expression of 11 cytochrome P450, 13 ABC transporter, 13 lipid metabolism and one vitellogenin genes. No gene was upregulated by LiCl or Li(2)CO(3). These results suggest that LiCl and Li(2)CO(3) potentially affect the biological and physiological function in C. elegans associated with alteration of the gene expression such as metabolic genes. Our data also provide experimental support for the utility of toxicogenomics by integrating gene expression profiling into a toxicological study of an environmentally important organism such as C. elegans.

  19. Growth and reproductive performance of two rabbit breeds reared under intensive system in Ghana.

    PubMed

    Apori, Samuel Obeng; Hagan, Julius Kofi; Osei, Yaa Doris

    2015-01-01

    A study on the growth and reproductive performance of two rabbit breeds was undertaken. Data on 588 kits and 97 does of California White and 574 kits and 90 does of New Zealand White rabbits reared under hot and humid environment in Ghana were taken. The reproductive performance of the two breeds, in terms of litter size at birth and weaning, litter weight at birth and weaning, kindling interval, age at sexual maturity, and gestation length as influenced by breed, season of kindling (rainy and dry), year of kindling (2005-2012), and parity (first to sixth and over) were determined. The performance of California White in terms of litter size at birth, at weaning, kit weight at birth, and age at first kindling was 5.9 ± 0.2, 4.6 ± 0.1, 54.7 ± 0.4 g, and 159.8 ± 0.2 days, respectively. That of New Zealand White was 5.9 ± 0.1, 5.1 ± 0.1, 55.2 ± 1.0 g, and 159.9 ± 0.2 days, respectively. The results obtained also showed a significant breed effects on kit weight at birth, litter weight at weaning, and mortality; whereas no significant differences (p > 0.05) were observed between the two breeds regarding the other traits measured. Parity had significant effects (p < 0.05) on all the growth and reproductive parameters measured with the exception of age at first kindling. Year of kindling also had significant effect on litter weight at birth, kit weight at birth, and at weaning (p < 0.05) but did not have any significant effect on the age at sexual maturity and mortality. Season also had significant (p < 0.05) effects on kit weight at birth, gestation length, kindling interval, and mortality with better performance experienced during the rainy season.

  20. Fibroblast growth factor receptor-3 regulates Paneth cell lineage allocation and accrual of epithelial stem cells during murine intestinal development.

    PubMed

    Vidrich, Alda; Buzan, Jenny M; Brodrick, Brooks; Ilo, Chibuzo; Bradley, Leigh; Fendig, Kirstin Skaar; Sturgill, Thomas; Cohn, Steven M

    2009-07-01

    Fibroblast growth factor receptor 3 (FGFR-3) is expressed in the lower crypt epithelium, where stem cells of the intestine reside. The role of FGFR-3 signaling in regulating features of intestinal morphogenesis was examined in FGFR-3-null (FGFR-3(-/-)) mice. FGFR-3(-/-) mice had only about half the number of intestinal crypts and a marked decrease in the number of functional clonogenic stem cells, as assessed by an in vivo microcolony-forming assay, compared with wild-type littermates. A marked deficit in allocation of progenitor cells to Paneth cell differentiation was noted, although all the principal epithelial lineages were represented in FGFR-3(-/-) mice. The total cellular content and nuclear localization of beta-catenin protein were reduced in FGFR-3(-/-) mice, as was expression of cyclin D1 and matrix metalloproteinase-7, major downstream targets of beta-catenin/T cell factor-4 (Tcf-4) signaling. Activation of FGFR-3 in Caco-2 cells, an intestinal epithelial cell line, abrogated the fall in beta-catenin/Tcf-4 signaling activity that is normally observed in these cells as cultures become progressively more confluent. These findings are consistent with the hypothesis that, during intestinal development, FGFR-3 signaling regulates crypt epithelial stem cell expansion and crypt morphogenesis, as well as Paneth cell lineage specification, through beta-catenin/Tcf-4-dependent and -independent pathways. PMID:19407216

  1. Cation Uptake and Allocation by Red Pine Seedlings under Cation-Nutrient Stress in a Column Growth Experiment

    SciTech Connect

    Shi, Zhenqing; Balogh-Brunstad, Zsuzsanna; Grant, Michael R.; Harsh, James B.; Gill, Richard; Thomashow, Linda; Dohnalkova, Alice; Stacks, Daryl; Letourneau, Melissa; Keller, Chester K.

    2014-01-10

    Background and Aims Plant nutrient uptake is affected by environmental stress, but how plants respond to cation-nutrient stress is poorly understood. We assessed the impact of varying degrees of cation-nutrient limitation on cation uptake in an experimental plant-mineral system. Methods Column experiments, with red pine (Pinus resinosa Ait.) seedlings growing in sand/mineral mixtures, were conducted for up to nine months under a range of Ca- and K-limited conditions. The Ca and K were supplied from both minerals and nutrient solutions with varying Ca and K concentrations. Results Cation nutrient stress had little impact on carbon allocation after nine months of plant growth and K was the limiting nutrient for biomass production. The Ca/Sr and K/Rb ratio results allowed independent estimation of dissolution incongruency and discrimination against Sr and Rb during cation uptake processes. The fraction of K in biomass from biotite increased with decreasing K supply from nutrient solutions. The mineral anorthite was consistently the major source of Ca, regardless of nutrient treatment. Conclusions Red pine seedlings exploited more mineral K in response to more severe K deficiency. This did not occur for Ca. Plant discrimination factors must be carefully considered to accurately identify nutrient sources using cation tracers.

  2. Effects of space allocation within a deep-bedded finishing system on pig growth performance, fatty acid composition and pork quality.

    PubMed

    Patton, B S; Huff-Lonergan, E; Honeyman, M S; Kerr, B J; Lonergan, S M

    2008-03-01

    The objectives of the current study were to determine the degree to which space allocation in a deep-bedded system influences swine performance and pork quality. The deep-bedded method employed was hoop structures, which are large, tent-like shelters with cornstalks or straw for bedding. One hundred gilts ranging in weight from 59 to 71 kg were randomly assigned to treatments of low (0.70 m2 per pig, n = 50) or high (1.13 m2 per pig, n = 50) space allocation. During the 45-day experimental period, gilts were ad libitum fed a two-phase diet. Six gilts per treatment were used for carcass composition and pork quality evaluation for each replication. Five replications were conducted over a period of 4 months. Pigs finished with greater space allocation had smaller longissimus muscle area and produced pork that appeared to be darker. Variations in fatty acid composition and lipid percentage of subcutaneous adipose and longissimus dorsi muscle were observed when space allocation was changed within hoop structures. Less space resulted in greater proportion of lipid present as polyunsaturated fatty acids. Greater space allocation resulted in lower total lipid in subcutaneous pork adipose tissue. Space allocation did not affect fat firmness. Replications spanned the months of August to November, with temperatures ranging from 32°C to -2°C within the hoop structure. As environmental temperature declined, the proportion of monounsaturated fatty acids increased. Providing more space during finishing in these systems had only a small affect on pig growth and pork quality. Variations observed from replication to replication at fluctuating temperatures provide insight to seasonal differences in growth and adipose tissue composition and firmness. Therefore, finishing pigs in these systems may lead to seasonal variation in lipid composition.

  3. Non-structural carbon dynamics and allocation relate to growth rate and leaf habit in California oaks.

    PubMed

    Trumbore, Susan; Czimczik, Claudia I; Sierra, Carlos A; Muhr, Jan; Xu, Xiaomei

    2015-11-01

    Trees contain non-structural carbon (NSC), but it is unclear for how long these reserves are stored and to what degree they are used to support plant activity. We used radiocarbon ((14)C) to show that the carbon (C) in stemwood NSC can achieve ages of several decades in California oaks. We separated NSC into two fractions: soluble (∼50% sugars) and insoluble (mostly starch) NSC. Soluble NSC contained more C than insoluble NSC, but we found no consistent trend in the amount of either pool with depth in the stem. There was no systematic difference in C age between the two fractions, although ages increased with stem depth. The C in both NSC fractions was consistently younger than the structural C from which they were extracted. Together, these results indicate considerable inward mixing of NSC within the stem and rapid exchange between soluble and insoluble pools, compared with the timescale of inward mixing. We observed similar patterns in sympatric evergreen and deciduous oaks and the largest differences among tree stems with different growth rates. The (14)C signature of carbon dioxide (CO2) emitted from tree stems was higher than expected from very recent photoassimilates, indicating that the mean age of C in respiration substrates included a contribution from C fixed years previously. A simple model that tracks NSC produced each year, followed by loss (through conversion to CO2) in subsequent years, matches our observations of inward mixing of NSC in the stem and higher (14)C signature of stem CO2 efflux. Together, these data support the idea of continuous accumulation of NSC in stemwood and that 'vigor' (growth rate) and leaf habit (deciduous vs evergreen) control NSC pool size and allocation.

  4. Non-structural carbon dynamics and allocation relate to growth rate and leaf habit in California oaks.

    PubMed

    Trumbore, Susan; Czimczik, Claudia I; Sierra, Carlos A; Muhr, Jan; Xu, Xiaomei

    2015-11-01

    Trees contain non-structural carbon (NSC), but it is unclear for how long these reserves are stored and to what degree they are used to support plant activity. We used radiocarbon ((14)C) to show that the carbon (C) in stemwood NSC can achieve ages of several decades in California oaks. We separated NSC into two fractions: soluble (∼50% sugars) and insoluble (mostly starch) NSC. Soluble NSC contained more C than insoluble NSC, but we found no consistent trend in the amount of either pool with depth in the stem. There was no systematic difference in C age between the two fractions, although ages increased with stem depth. The C in both NSC fractions was consistently younger than the structural C from which they were extracted. Together, these results indicate considerable inward mixing of NSC within the stem and rapid exchange between soluble and insoluble pools, compared with the timescale of inward mixing. We observed similar patterns in sympatric evergreen and deciduous oaks and the largest differences among tree stems with different growth rates. The (14)C signature of carbon dioxide (CO2) emitted from tree stems was higher than expected from very recent photoassimilates, indicating that the mean age of C in respiration substrates included a contribution from C fixed years previously. A simple model that tracks NSC produced each year, followed by loss (through conversion to CO2) in subsequent years, matches our observations of inward mixing of NSC in the stem and higher (14)C signature of stem CO2 efflux. Together, these data support the idea of continuous accumulation of NSC in stemwood and that 'vigor' (growth rate) and leaf habit (deciduous vs evergreen) control NSC pool size and allocation. PMID:26452766

  5. Incorporating Temperature-driven Seasonal Variation in Survival, Growth, and Reproduction Models for Small Fish

    EPA Science Inventory

    Seasonal variation in survival and reproduction can be a large source of prediction uncertainty in models used for conservation and management. A seasonally varying matrix population model is developed that incorporates temperature-driven differences in mortality and reproduction...

  6. The dynamic of the annual carbon allocation to wood in European tree species is consistent with a combined source-sink limitation of growth: implications for modelling

    NASA Astrophysics Data System (ADS)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrene, E.; Francois, C.; Soudani, K.; Ourcival, J. M.; Delpierre, N.

    2015-05-01

    The extent to which wood growth is limited by carbon (C) supply (i.e. source control) or by cambial activity (i.e. sink control) will strongly determine the responses of trees to global changes. Nevertheless, the physiological processes that are responsible for limiting forest growth are still a matter of debate. The aim of this study was to evaluate the key determinants of the annual C allocation to wood along large soil and climate regional gradients over France. The study was conducted for five tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex, Quercus robur and Picea abies). The drivers of stand biomass growth were assessed on both inter-site and inter-annual scales. Our data set comprised field measurements performed at 49 sites (931 site-years) that included biometric measurements and a variety of stand characteristics (e.g. soil water holding capacity, leaf area index). It was complemented with process-based simulations when possible explanatory variables could not be directly measured (e.g. annual and seasonal tree C balance, bioclimatic water stress indices). Specifically, the relative influences of tree C balance (source control), direct environmental control (water and temperature controls of sink activity) and allocation adjustments related to age, past climate conditions, competition intensity and soil nutrient availability on growth were quantified. The inter-site variability in the stand C allocation to wood was predominantly driven by age-related decline. The direct effects of temperature and water stress on sink activity (i.e. effects independent from their effects on the C supply) exerted a strong influence on the annual stand wood growth in all of the species considered, including deciduous temperate species. The lagged effect of the past environmental conditions (e.g. the previous year's water stress and low C uptake) significantly affected the annual C allocation to wood. The C supply

  7. Reproductive efficiency and shade avoidance plasticity under simulated competition.

    PubMed

    Fazlioglu, Fatih; Al-Namazi, Ali; Bonser, Stephen P

    2016-07-01

    Plant strategy and life-history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life-history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life-history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants.

  8. Reproductive efficiency and shade avoidance plasticity under simulated competition.

    PubMed

    Fazlioglu, Fatih; Al-Namazi, Ali; Bonser, Stephen P

    2016-07-01

    Plant strategy and life-history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life-history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life-history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants. PMID:27547325

  9. Effect of dsRNA on growth rate and reproductive potential of Monosporascus cannonballus.

    PubMed

    Armengol, Josep; Alaniz, Sandra; Vicent, Antonio; Beltrán, Roberto; Abad-Campos, Paloma; Pérez-Sierra, Ana; García-Jiménez, José; Ben Salem, Ibtissem; Souli, Mounira; Boughalleb, Naima

    2011-03-01

    The effect of double stranded RNA (dsRNA) infection on growth rate and the reproductive potential of Monosporascus cannonballus was studied in 21 isolates collected in cucurbit growing areas of Spain and Tunisia. The isolates were incubated on potato dextrose agar (PDA) under different conditions of temperature, pH, and water potential (Ψ(s)). They showed optimal growth temperatures over the range of 27-34°C and perithecia formation was obtained mainly at 25 and 30°C, although some isolates were able to produce perithecia at 35°C. All isolates were able to produce perithecia in a broad range of pHs (4-8). Regarding the effect of Ψ(s,) the isolates were more tolerant to grow on KCl than on NaCl. For each solute, radial growth decreased progressively as Ψ(s) decreased and was severely limited at -5.0 to -6.0MPa. Perithecia formation was highest at -0.5MPa, decreased at -1.0MPa and occurred just in some isolates at -2.0MPa. Nine of the M. cannonballus isolates harboured dsRNA with 2-6 bands each and a size range of 1.9-18.0Kb. Phenotypical data were subjected to multivariate factorial analysis. Most of the isolates clustered in two groups corresponding with the presence/absence of dsRNA elements. Isolates without detectable dsRNA produced more perithecia. However, isolates with dsRNA produced lower number of perithecia depending on the pH, Ψ(s,) or solute used. These results improve our understanding of the behaviour and growth of this pathogen in soil, and can be useful to implement effective disease control.

  10. A trade-off between reproduction and feather growth in the barn swallow (Hirundo rustica).

    PubMed

    Saino, Nicola; Romano, Maria; Rubolini, Diego; Ambrosini, Roberto; Romano, Andrea; Caprioli, Manuela; Costanzo, Alessandra; Bazzi, Gaia

    2014-01-01

    Physiological trade-offs mediated by limiting energy, resources or time constrain the simultaneous expression of major functions and can lead to the evolution of temporal separation between demanding activities. In birds, plumage renewal is a demanding activity, which accomplishes fundamental functions, such as allowing thermal insulation, aerodynamics and socio-sexual signaling. Feather renewal is a very expensive and disabling process, and molt is often partitioned from breeding and migration. However, trade-offs between feather renewal and breeding have been only sparsely studied. In barn swallows (Hirundo rustica) breeding in Italy and undergoing molt during wintering in sub-Saharan Africa, we studied this trade-off by removing a tail feather from a large sample of individuals and analyzing growth bar width, reflecting feather growth rate, and length of the growing replacement feather in relation to the stage in the breeding cycle at removal and clutch size. Growth bar width of females and length of the growing replacement feather of both sexes were smaller when the original feather had been removed after clutch initiation. Importantly, in females both growth bar width and replacement feather length were negatively predicted by clutch size, and more strongly so for large clutches and when feather removal occurred immediately after clutch completion. Hence, we found strong, coherent evidence for a trade-off between reproduction, and laying effort in particular, and the ability to generate new feathers. These results support the hypothesis that the derived condition of molting during wintering in long-distance migrants is maintained by the costs of overlapping breeding and molt.

  11. Effect of dsRNA on growth rate and reproductive potential of Monosporascus cannonballus.

    PubMed

    Armengol, Josep; Alaniz, Sandra; Vicent, Antonio; Beltrán, Roberto; Abad-Campos, Paloma; Pérez-Sierra, Ana; García-Jiménez, José; Ben Salem, Ibtissem; Souli, Mounira; Boughalleb, Naima

    2011-03-01

    The effect of double stranded RNA (dsRNA) infection on growth rate and the reproductive potential of Monosporascus cannonballus was studied in 21 isolates collected in cucurbit growing areas of Spain and Tunisia. The isolates were incubated on potato dextrose agar (PDA) under different conditions of temperature, pH, and water potential (Ψ(s)). They showed optimal growth temperatures over the range of 27-34°C and perithecia formation was obtained mainly at 25 and 30°C, although some isolates were able to produce perithecia at 35°C. All isolates were able to produce perithecia in a broad range of pHs (4-8). Regarding the effect of Ψ(s,) the isolates were more tolerant to grow on KCl than on NaCl. For each solute, radial growth decreased progressively as Ψ(s) decreased and was severely limited at -5.0 to -6.0MPa. Perithecia formation was highest at -0.5MPa, decreased at -1.0MPa and occurred just in some isolates at -2.0MPa. Nine of the M. cannonballus isolates harboured dsRNA with 2-6 bands each and a size range of 1.9-18.0Kb. Phenotypical data were subjected to multivariate factorial analysis. Most of the isolates clustered in two groups corresponding with the presence/absence of dsRNA elements. Isolates without detectable dsRNA produced more perithecia. However, isolates with dsRNA produced lower number of perithecia depending on the pH, Ψ(s,) or solute used. These results improve our understanding of the behaviour and growth of this pathogen in soil, and can be useful to implement effective disease control. PMID:21354530

  12. Growth, biomass allocation and nutrient use efficiency in Cladium jamaicense and Typha domingensis as affected by phosphorus and oxygen availability

    USGS Publications Warehouse

    Lorenzen, B.; Brix, H.; Mendelssohn, I.A.; McKee, K.L.; Miao, S.L.

    2001-01-01

    The effects of phosphorus (P) and oxygen availability on growth, biomass allocation and nutrient use efficiency in Cladium jamaicense Crantz and Typha domingensis Pers. were studied in a growth facility equipped with steady-state hydroponic rhizotrons. The treatments included four P concentrations (10, 40, 80 and 500 ??g I-1) and two oxygen concentration (8.0 and <0.5 mg O2 I-1) in the culture solutions. In Cladium, no clear relationship was found between P availability and growth rate (19-37 mg g-1 d-1), the above to below ground biomass ratio (A/B) (mean = 4.6), or nitrogen use efficiency (NUE) (mean = 72 g dry weight g-1 N). However, the ratio between root supported tissue (leaves, rhizomes and ramets) and root biomass (S/R) (5.6-8) increased with P availability. In contrast, the growth rate (48-89 mg g-1 d-1) and the biomass ratios A/B (2.4-6.1) and S/R (5.4-10.3) of Typha increased with P availability, while NUE (71-30 g dry weight g-1 N) decreased. The proportion of root laterals was similar in the two species, but Typha had thinner root laterals (diameter = 186 ??m) than Cladium (diameter = 438 ??m) indicating a larger root surface area in Typha. The two species had a similar P use efficiency (PUE) at 10 ??g PI-1 (mean = 1134 g dry weight g-1 P) and at 40 and 80 ??g PI-1 (mean = 482 dry weight g-1 P) but the N/P ratio indicated imbalances in nutrient uptake at a higher P concentration (40 ??g PI-1) in Typha than in Cladium (10 ??g PI-1). The two species had similar root specific P accumulation rate at the two lowest P levels, whereas Typha had 3-13-fold higher P uptake rates at the two highest P levels, indicating a higher nutrient uptake capacity in Typha. The experimental oxygen concentration in the rhizosphere had only limited effect on the growth of the two species and had little effect on biomass partitioning and nutrient use efficiency. The aerenchyma in these species was probably sufficient to maintain adequate root oxygenation under partially oxygen

  13. Growth, reproductive biology and life cycle of the vermicomposting earthworm, Perionyx ceylanensis Mich. (Oligochaeta: Megascolecidae).

    PubMed

    Karmegam, Natchimuthu; Daniel, Thilagavathy

    2009-10-01

    In the present study, an attempt has been made to study the growth, reproduction and life cycle of the earthworm, Perionyx ceylanensis Mich. in cowdung for the period of 340 days. Results showed that the overall mean growth rate was 1.79, 1.57 and 1.34 mg/worm/day respectively for the worms cultured singly, in batches of four and eight. Cocoon production rate was found between 0.85 and 0.94 cocoons/worm/day and the hatching success between 74.67% and 82.67%. The majority of the cocoons (95.16-96.77%) hatched only one hatchling. Worms raised singly also produced viable cocoons indicating that P. ceylanensis reproduce parthenogenetically. The life cycle of the worms cultured singly was +/-57 days and it was +/-50 days for the worms cultured in batches of four and eight. There is a vast scope to utilize P. ceylanensis for vermiculture practices due to short period of life cycle.

  14. Effects of boron and selenium on mallard reproduction and duckling growth and survival

    USGS Publications Warehouse

    Stanley, T.R.; Smith, G.J.; Hoffman, D.J.; Heinz, G.H.; Rosscoe, R.

    1996-01-01

    Boron (B) and selenium (Se) sometimes occur together in high concentrations in the environment and can accumulate in plants and invertebrates consumed by waterfowl. One hundred twenty-six pairs of breeding mallards (Anas platyrhynchos) were fed diets supplemented with B (as boric acid) at 0, 450, or 900 ppm, in combination with Se (as seleno-DL-methionine) at 0, 3.5, or 7 ppm, in a replicated factorial experiment. Ducklings produced received the same treatment combination as their parents. Boron and Se accumulated in adult liver, egg, and duckling liver. In adults, B and Se caused weight loss, and B decreased hemoglobin concentration, egg weight, and egg fertility. Both B and Se reduced hatching success and duckling weight, and B reduced duckling growth and duckling production, and caused several alterations in duckling liver biochemistry. Duckling survival was not reduced by B or Se, and neither B nor Se had histopathologic effects on adult or duckling liver, kidney, or spleen. There was little evidence of interaction between B and Se. This study demonstrated that B and Se, in the chemical forms and at the dietary levels administered in this study, can adversely affect mallard reproduction and duckling growth.

  15. Growth, reproduction & population structure of the freshwater crab Sinopotamon yangtsekiense bott, 1967, from Zhejiang, China

    NASA Astrophysics Data System (ADS)

    Chen, Tao; Lai, Wei; Du, Nan-Shan

    1994-03-01

    Monthly investigations were mae on the population of Chinese freshwater crab, Sinopotamon yangtsekiense Bott, 1967 from April, 1984 to March, 1985. The data on 4413 specimens show that the growth was affected mainly by temperature. During the April to November growth period, the crabs' major development occurred from June through October. One year was required for a fine white oocyte to develop into a mature egg. The reproduction period was June October. Females bearing eggs were taken from June August, and crabs with young were found from July October. The females reproduced once a year but could for more than one year. The number of eggs carried by a female varied greatly according to the size of the crab, ranging from 30 to 100 eggs. New-born crabs become mature after 1 2 years. The sex ratio was approximately 1∶1 in the overall population. However, the larger crabs are predominantly male. The age distribution of S. yangtsekinese was estimated from size frequency histograms. There were more adult crabs (over 70%) from June to October and more immature crabs (over 50%) from November to May.

  16. Growth and reproduction of laboratory-reared neanurid Collembola using a novel slime mould diet

    NASA Astrophysics Data System (ADS)

    Hoskins, Jessica L.; Janion-Scheepers, Charlene; Chown, Steven L.; Duffy, Grant A.

    2015-07-01

    Although significant progress has been made using insect taxa as model organisms, non-tracheated terrestrial arthropods, such as Collembola, are underrepresented as model species. This underrepresentation reflects the difficulty in maintaining populations of specialist Collembola species in the laboratory. Until now, no species from the family Neanuridae have been successfully reared. Here we use controlled growth experiments to provide explicit evidence that the species Neanura muscorum can be raised under laboratory conditions when its diet is supplemented with slime mould. Significant gains in growth were observed in Collembola given slime mould rather than a standard diet of algae-covered bark. These benefits are further highlighted by the reproductive success of the experimental group and persistence of laboratory breeding stocks of this species and others in the family. The necessity for slime mould in the diet is attributed to the ‘suctorial’ mouthpart morphology characteristic of the Neanuridae. Maintaining laboratory populations of neanurid Collembola species will facilitate their use as model organisms, paving the way for studies that will broaden the current understanding of the environmental physiology of arthropods.

  17. Growth and reproduction of laboratory-reared neanurid Collembola using a novel slime mould diet.

    PubMed

    Hoskins, Jessica L; Janion-Scheepers, Charlene; Chown, Steven L; Duffy, Grant A

    2015-07-08

    Although significant progress has been made using insect taxa as model organisms, non-tracheated terrestrial arthropods, such as Collembola, are underrepresented as model species. This underrepresentation reflects the difficulty in maintaining populations of specialist Collembola species in the laboratory. Until now, no species from the family Neanuridae have been successfully reared. Here we use controlled growth experiments to provide explicit evidence that the species Neanura muscorum can be raised under laboratory conditions when its diet is supplemented with slime mould. Significant gains in growth were observed in Collembola given slime mould rather than a standard diet of algae-covered bark. These benefits are further highlighted by the reproductive success of the experimental group and persistence of laboratory breeding stocks of this species and others in the family. The necessity for slime mould in the diet is attributed to the 'suctorial' mouthpart morphology characteristic of the Neanuridae. Maintaining laboratory populations of neanurid Collembola species will facilitate their use as model organisms, paving the way for studies that will broaden the current understanding of the environmental physiology of arthropods.

  18. Growth and reproduction of laboratory-reared neanurid Collembola using a novel slime mould diet.

    PubMed

    Hoskins, Jessica L; Janion-Scheepers, Charlene; Chown, Steven L; Duffy, Grant A

    2015-01-01

    Although significant progress has been made using insect taxa as model organisms, non-tracheated terrestrial arthropods, such as Collembola, are underrepresented as model species. This underrepresentation reflects the difficulty in maintaining populations of specialist Collembola species in the laboratory. Until now, no species from the family Neanuridae have been successfully reared. Here we use controlled growth experiments to provide explicit evidence that the species Neanura muscorum can be raised under laboratory conditions when its diet is supplemented with slime mould. Significant gains in growth were observed in Collembola given slime mould rather than a standard diet of algae-covered bark. These benefits are further highlighted by the reproductive success of the experimental group and persistence of laboratory breeding stocks of this species and others in the family. The necessity for slime mould in the diet is attributed to the 'suctorial' mouthpart morphology characteristic of the Neanuridae. Maintaining laboratory populations of neanurid Collembola species will facilitate their use as model organisms, paving the way for studies that will broaden the current understanding of the environmental physiology of arthropods. PMID:26153104

  19. Growth and reproduction of laboratory-reared neanurid Collembola using a novel slime mould diet

    PubMed Central

    Hoskins, Jessica L.; Janion-Scheepers, Charlene; Chown, Steven L.; Duffy, Grant A.

    2015-01-01

    Although significant progress has been made using insect taxa as model organisms, non-tracheated terrestrial arthropods, such as Collembola, are underrepresented as model species. This underrepresentation reflects the difficulty in maintaining populations of specialist Collembola species in the laboratory. Until now, no species from the family Neanuridae have been successfully reared. Here we use controlled growth experiments to provide explicit evidence that the species Neanura muscorum can be raised under laboratory conditions when its diet is supplemented with slime mould. Significant gains in growth were observed in Collembola given slime mould rather than a standard diet of algae-covered bark. These benefits are further highlighted by the reproductive success of the experimental group and persistence of laboratory breeding stocks of this species and others in the family. The necessity for slime mould in the diet is attributed to the ‘suctorial’ mouthpart morphology characteristic of the Neanuridae. Maintaining laboratory populations of neanurid Collembola species will facilitate their use as model organisms, paving the way for studies that will broaden the current understanding of the environmental physiology of arthropods. PMID:26153104

  20. The dynamics of annual carbon allocation to wood in European forests is consistent with a combined source-sink limitation of growth.

    NASA Astrophysics Data System (ADS)

    Guillemot, Joannès; Martin-StPaul, Nicolas K.; Dufrêne, Eric; François, Christophe; Soudani, Kamel; Ourcival, Jean-Marc; Leadley, Paul; Delpierre, Nicolas

    2015-04-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will strongly determines the responses of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study was i) to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in four tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex and Picea abies) ii) to implement the identified key drivers in a new C allocation scheme within the CASTANEA terrestrial biosphere model (TBM). Combining field measurements and process-based simulations at 49 sites (931 site-years), our analyses revealed that the inter-site variability in C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. Our study supports the premise that European forest growth is under a complex panel of source- and sink- limitations, contradicting the simple source control implemented in most TBMs. The implementation of these combined forest growth limitations in the CASTANEA model significantly improved its performance when evaluated against independent stand growth data at the regional scale (mainland France, >10000 plots). We finally discuss how the sink imitation affects the CASTANEA simulated projections of forest productivity along the 21th century, especially with respect to the expected fertilizing effect of increasing atmospheric

  1. Impacts of an endoparasitic copepod, Ismaila belciki, on the reproduction, growth and survivorship of its nudibranch host, Janolus fuscus.

    PubMed

    Wolf, Maya; Young, Craig M

    2014-05-01

    Copepods from the genus Ismaila are large endoparasites that inhabit the main body cavity and/or cerata of opisthobranch molluscs. These parasites exhibit many life history characteristics typically found in parasitic castrators, yet the actual impact of infection on reproduction, growth or survivorship of the hosts are unknown. On the Oregon (USA) coast, Ismaila belciki can infect over 80% of their hermaphroditic hosts, Janolus fuscus. In laboratory mating experiments, we compared the reproductive output (egg mass weight, number of egg capsules, number of viable embryos) and the gonadal somatic index of infected versus uninfected J. fuscus. Infected J. fuscus could produce viable sperm and copulate. Mating with an infected individual did not limit a sea slug's reproductive output. However, infected J. fuscus had significantly lower reproductive output (by 34-54%), producing smaller egg masses with fewer capsules and viable embryos. Infected hosts had significantly lower gonadal somatic index than their uninfected counterparts, although there was no significant difference in gonadal somatic index between hosts with single and double infections. By collecting the egg sacs produced by the copepod parasite during experiments, we estimated that 25-34% of the host's reproductive output is usurped by the parasite and re-directed to the parasite's own reproduction. In the laboratory, infection did not alter growth in J. fuscus. However, infection significantly decreased survivorship in mature (but not immature) nudibranch hosts. These results suggest that I. belciki is not a true castrator, but it does reduce the reproductive output of its host and may therefore limit the natural population size of J. fuscus. PMID:24590063

  2. Transgenerational Effects of Early Life Starvation on Growth, Reproduction, and Stress Resistance in Caenorhabditis elegans

    PubMed Central

    Jobson, Meghan A.; Jordan, James M.; Sandrof, Moses A.; Hibshman, Jonathan D.; Lennox, Ashley L.; Baugh, L. Ryan

    2015-01-01

    Starvation during early development can have lasting effects that influence organismal fitness and disease risk. We characterized the long-term phenotypic consequences of starvation during early larval development in Caenorhabditis elegans to determine potential fitness effects and develop it as a model for mechanistic studies. We varied the amount of time that larvae were developmentally arrested by starvation after hatching (“L1 arrest”). Worms recovering from extended starvation grew slowly, taking longer to become reproductive, and were smaller as adults. Fecundity was also reduced, with the smallest individuals most severely affected. Feeding behavior was impaired, possibly contributing to deficits in growth and reproduction. Previously starved larvae were more sensitive to subsequent starvation, suggesting decreased fitness even in poor conditions. We discovered that smaller larvae are more resistant to heat, but this correlation does not require passage through L1 arrest. The progeny of starved animals were also adversely affected: Embryo quality was diminished, incidence of males was increased, progeny were smaller, and their brood size was reduced. However, the progeny and grandprogeny of starved larvae were more resistant to starvation. In addition, the progeny, grandprogeny, and great-grandprogeny were more resistant to heat, suggesting epigenetic inheritance of acquired resistance to starvation and heat. Notably, such resistance was inherited exclusively from individuals most severely affected by starvation in the first generation, suggesting an evolutionary bet-hedging strategy. In summary, our results demonstrate that starvation affects a variety of life-history traits in the exposed animals and their descendants, some presumably reflecting fitness costs but others potentially adaptive. PMID:26187123

  3. Effect on growth and reproduction of hormone immersed and masculinized fighting fish Betta splendens.

    PubMed

    Kirankumar, Santhakumar; Pandian, Thavamani Jegajothivel

    2002-11-01

    To produce all-male progenies in the fighting fish, Betta splendens, six groups of fry were subjected to discrete immersion treatment at different 17alpha-methyltestosterone (MT) doses (viz. 100, 200, 500, 700, 900, and 1,000 microg/l) for a constant duration (3 hr/day) and frequency (second, fifth, and eighth day after hatching). The treatment at 900 microg/l led to 98% masculinization and 71% survival at sexual maturity. Treated groups, which showed significant deviation from the 1:1 sex ratio, were classified into two different series: S1 and S2. The groups that showed nearly cent-percent masculinization were classified as S1, and the other groups were classified as S2. The S1 males showed remarkably slower growth and attained 3.5 cm total length compared to 6.0 cm attained by a normal male. The S2 males attained 5.4 cm total length. Apart from these morphological defects, both S1 and S2 males suffered functional (decreased sperm count and sperm motility) and behavioral defects (incomplete embracing during mating) in their reproductive ability, leading to approximately 50% and 30% reduction in fecundity per mating, respectively. The cumulative fecundity loss suffered by the S1 male during its active reproductive phase is discussed. When normal and sex-reversed males were presented, a female preferred the former. Progeny testing of the sex-reversed males showed the occurrence of 12.75% males, indicating the possible role of autosomal genes in the sex determination mechanism of this species. Discrete immersion treatment at optimal/super-optimal doses ensured not only a higher percentage of masculinization, but also a higher frequency of homogametic males (XX).

  4. Effect on growth and reproduction of hormone immersed and masculinized fighting fish Betta splendens.

    PubMed

    Kirankumar, Santhakumar; Pandian, Thavamani Jegajothivel

    2002-11-01

    To produce all-male progenies in the fighting fish, Betta splendens, six groups of fry were subjected to discrete immersion treatment at different 17alpha-methyltestosterone (MT) doses (viz. 100, 200, 500, 700, 900, and 1,000 microg/l) for a constant duration (3 hr/day) and frequency (second, fifth, and eighth day after hatching). The treatment at 900 microg/l led to 98% masculinization and 71% survival at sexual maturity. Treated groups, which showed significant deviation from the 1:1 sex ratio, were classified into two different series: S1 and S2. The groups that showed nearly cent-percent masculinization were classified as S1, and the other groups were classified as S2. The S1 males showed remarkably slower growth and attained 3.5 cm total length compared to 6.0 cm attained by a normal male. The S2 males attained 5.4 cm total length. Apart from these morphological defects, both S1 and S2 males suffered functional (decreased sperm count and sperm motility) and behavioral defects (incomplete embracing during mating) in their reproductive ability, leading to approximately 50% and 30% reduction in fecundity per mating, respectively. The cumulative fecundity loss suffered by the S1 male during its active reproductive phase is discussed. When normal and sex-reversed males were presented, a female preferred the former. Progeny testing of the sex-reversed males showed the occurrence of 12.75% males, indicating the possible role of autosomal genes in the sex determination mechanism of this species. Discrete immersion treatment at optimal/super-optimal doses ensured not only a higher percentage of masculinization, but also a higher frequency of homogametic males (XX). PMID:12410610

  5. Modelling Growth and Partitioning of Annual Above-Ground Vegetative and Reproductive Biomass of Grapevine

    NASA Astrophysics Data System (ADS)

    Meggio, Franco; Vendrame, Nadia; Maniero, Giovanni; Pitacco, Andrea

    2014-05-01

    In the current climate change scenarios, both agriculture and forestry inherently may act as carbon sinks and consequently can play a key role in limiting global warming. An urgent need exists to understand which land uses and land resource types have the greatest potential to mitigate greenhouse gas (GHG) emissions contributing to global change. A common believe is that agricultural fields cannot be net carbon sinks due to many technical inputs and repeated disturbances of upper soil layers that all contribute to a substantial loss both of the old and newly-synthesized organic matter. Perennial tree crops (vineyards and orchards), however, can behave differently: they grow a permanent woody structure, stand undisturbed in the same field for decades, originate a woody pruning debris, and are often grass-covered. In this context, reliable methods for quantifying and modelling emissions and carbon sequestration are required. Carbon stock changes are calculated by multiplying the difference in oven dry weight of biomass increments and losses with the appropriate carbon fraction. These data are relatively scant, and more information is needed on vineyard management practices and how they impact vineyard C sequestration and GHG emissions in order to generate an accurate vineyard GHG footprint. During the last decades, research efforts have been made for estimating the vineyard carbon budget and its allocation pattern since it is crucial to better understand how grapevines control the distribution of acquired resources in response to variation in environmental growth conditions and agronomic practices. The objective of the present study was to model and compare the dynamics of current year's above-ground biomass among four grapevine varieties. Trials were carried out over three growing seasons in field conditions. The non-linear extra-sums-of-squares method demonstrated to be a feasible way of growth models comparison to statistically assess significant differences among

  6. Main and interactive effects of arsenic and selenium on mallard reproduction and duckling growth and survival

    USGS Publications Warehouse

    Stanley, T.R.; Spann, J.W.; Smith, G.J.; Rosscoe, R.

    1994-01-01

    Arsenic (As) and selenium (Se) occur together in high concentrations in the environment and can accumulate in aquatic plants and invertebrates consumed by waterfowl. Ninety-nine pairs of breeding mallards (Anas platyrhynchos) were fed diets supplemented with As (sodium arsenate) at 0, 25, 100, or 400 ug/g, in combination with Se (seleno-DL-methionine) at 0 or 10 ug/g, in a replicated factorial experiment. Ducklings produced were placed on the same treatment combination as their parents. Arsenic accumulated in adult liver and egg, reduced adult weight gain and liver weight, delayed the onset of egg laying, decreased whole egg weight, and caused eggshell thinning. Arsenic did not affect hatching success and was not teratogenic. In ducklings, As accumulated in the liver and reduced body weight, growth, and liver weight. Arsenic did not increase duckling mortality, but it did decrease overall duckling production. Selenium accumulated in adult liver and egg, was teratogenic, and decreased hatching success. Selenium did not affect adult weight, liver weight, survival, onset of egg laying, egg fertility, egg weight, or eggshell thickness. In ducklings, Se accumulated in the liver and reduced body weight and growth, and increased liver weight. Selenium increased duckling mortality and decreased overall duckling production. Antagonistic interactions between As and Se occurred whereby As reduced Se accumulation in liver and egg, and alleviated the effects of Se on hatching success and embryo deformities. It was demonstrated that As and Se, in the chemical forms and at the dietary levels administered in this study, can adversely affect mallard reproduction and duckling growth and survival, and that As can alleviate toxic effects of Se.

  7. Subchronic effects of five di-ortho PCB congeners on survival, growth and reproduction in the fathead minnow Pimephales promelas

    SciTech Connect

    Suedel, B.C.; Dillon, T.M.; Benson, W.H.

    1997-07-01

    The effects of five di-ortho polychlorinated biphenyl (PCB) congeners on survival, growth, and reproduction in the fathead minnow. Pimephales promelas, were determined. Fish were exposed to one of two nominal concentrations of each congener for a total of 13 weeks (7-week prespawning period plus 6-week spawning period) under flow-through conditions using methanol as a carrier solvent. At termination, P. promelas survival was high in all PCB congener treatments. PCB congeners had no significant sublethal effects on reproductive success within the concentration range examined. The total number of eggs, clutch size, number of clutches, percent hatchability, and presence of terata in offspring were not significantly affected. Reproductive success was slightly but not significantly enhanced in the solvent control and high treatment concentrations for congeners 52, 101, 138, and 153. Growth expressed as wet weight was not affected for both adult males or females. Male lengths were not significantly affected but female lengths were significantly reduced when exposed to congeners 101, 138, 153, and 180. Pimephales promelas accumulated substantial amounts of all PCBs, with tissue concentrations ranging from 13 to 183 mg/kg wet weight at termination in PCB-exposed fish. These tissue residues are one to several orders of magnitude greater than those reported for these congeners in aquatic biota previously collected in industrial waterways of the Great Lakes. Several di-ortho PCB congeners frequently found in aquatic biota showed minimal adverse effects on fathead minnow survival, growth, and reproduction even though bioaccumulation of these congeners was substantial.

  8. Sex-related differences in growth and carbon allocation to defence in Populus tremula as explained by current plant defence theories.

    PubMed

    Randriamanana, Tendry R; Nybakken, Line; Lavola, Anu; Aphalo, Pedro J; Nissinen, Katri; Julkunen-Tiitto, Riitta

    2014-05-01

    Plant defence theories have recently evolved in such a way that not only the quantity but also the quality of mineral nutrients is expected to influence plant constitutive defence. Recently, an extended prediction derived from the protein competition model (PCM) suggested that nitrogen (N) limitation is more important for the production of phenolic compounds than phosphorus (P). We aimed at studying sexual differences in the patterns of carbon allocation to growth and constitutive defence in relation to N and P availability in Populus tremula L. seedlings. We compared the gender responses in photosynthesis, growth and whole-plant allocation to phenolic compounds at different combination levels of N and P, and studied how they are explained by the main plant defence theories. We found no sexual differences in phenolic concentrations, but interestingly, slow-growing females had higher leaf N concentration than did males, and genders differed in their allocation priority. There was a trade-off between growth and the production of flavonoid-derived phenylpropanoids on one hand, and between the production of salicylates and flavonoid-derived phenylpropanoids on the other. Under limited nutrient conditions, females prioritized mineral nutrient acquisition, flavonoid and condensed tannin (CT) production, while males invested more in above-ground biomass. Salicylate accumulation followed the growth differentiation balance hypothesis as low N mainly decreased the production of leaf and stem salicylate content while the combination of both low N and low P increased the amount of flavonoids and CTs allocated to leaves and to a lesser extent stems, which agrees with the PCM. We suggest that such a discrepancy in the responses of salicylates and flavonoid-derived CTs is linked to their clearly distinct biosynthetic origins and/or their metabolic costs.

  9. Effects of food availability on growth and reproduction of the deep-sea pedunculate barnacle Heteralepas canci

    NASA Astrophysics Data System (ADS)

    Yasuda, Natsumi; Miyamoto, Norio; Fujiwara, Yoshihiro; Yamamoto, Tomoko; Yusa, Yoichi

    2016-02-01

    Sessile animals living on continental shelves or slopes may adjust their growth and reproduction according to temporally and spatially variable food availability, but little information is available on these animals to date. We collected the pedunculate barnacle Heteralepas canci on a continental slope at a depth of 229 m off Cape Nomamisaki in southern Japan. We developed a rearing method for the barnacles and studied their growth and reproduction at different food levels in the laboratory. A total of 136 individual H. canci were fed with Artemia salina larvae and brewer's yeast at three different food levels for 100 days. Both the growth and the ovary development were delayed when food availability was low, whereas the survival rate was lower at the high food level. In addition, an individual survived under complete starvation for 167 days. We concluded that H. canci has plastic life history traits that are adaptive for variable food availability.

  10. Helminths infection patterns in a lizard (Tropidurus hispidus) population from a semiarid neotropical area: associations between female reproductive allocation and parasite loads.

    PubMed

    Galdino, Conrado A B; Ávila, Robson W; Bezerra, Castiele H; Passos, Daniel C; Melo, Gabriela C; Zanchi-Silva, Djan

    2014-12-01

    This study reports helminth infection patterns of the lizard Tropidurus hispidus from an area of semiarid caatinga in northeastern Brazil (Ceará state). The lizard population was parasitized by 8 helminth species, and the species composition of the component community resembles that found for other Neotropical lizards. The prevalence of parasites was higher for males compared with females, whereas no relation was found between intensity of infection of 2 parasites (Parapharyngodon alvarengai and Physaloptera lutzi) and the lizards body size. For reproductive females, parasite infection intensity was negatively correlated to reproductive investment.

  11. Effect of commercial grade endosulfan on growth and reproduction of the fighting fish Betta splendens.

    PubMed

    Balasubramani, A; Pandian, T J

    2014-09-01

    To study the effects of endosulfan on survival, growth and reproduction of the obligate air-breathing male heterogametic fighting fish Betta splendens, posthatchlings of the fighting fish were discretely immersed for 3 h/day during the labile period on the 2nd, 5th, and 8th day posthatching (dph) at selected concentrations of commercial grade endosulfan ranging from 175 to 1400 ng/L. The immersions at 1,400 ng/L led to 21% mortality, among the 79% of surviving fry, 80% developed into females. The endosulfan reduced the air-breathing frequency of 5- and 8-day old hatchlings, and the reduction in the frequency persisted even after a depuration period of 172 days. In the ovary of the treated females, reduced number of vitellogenic oocytes with increased vacuolar cavities was observed. In the testis of the treated males, the reduced number of spermatogonia with increased vacuolar cavities was observed. The treated male induced the female to spawn a fewer eggs, which were subsequently incubated in his smaller bubble nest. The control females attained puberty on the 138th dph and spawned 120 eggs once in every 15 days, the females, which were previously treated at 1400 ng/L, postponed puberty to the 179th dph and spawned 70 eggs once in every 32 days. During the 240-day experiment, endosulfan is found to reduce significantly the cumulative progeny production from 760 to 144, reducing significantly to 19% of the control.

  12. Association of milk protein types with growth and reproductive performance of dairy heifers.

    PubMed

    Lin, C Y; McAllister, A J; Ng-Kwai-Hang, K F; Hayes, J F; Batra, T R; Lee, A J; Roy, G L; Vesely, J A; Wauthy, J M; Winter, K A

    1987-01-01

    A total of 890 heifers was used to study the effects of four milk protein loci (alpha S1-casein, beta-casein, kappa-casein, and beta-lactoglobulin) on heifer growth and reproduction. The additive effects of gene substitutions at the four milk protein loci were significant only in 4 of 56 cases for all traits studied. Dominance effects at alpha S1-casein, beta-casein, and kappa-casein loci were not significant for any traits except beta-casein locus on body weight at first calving. Heifers with AB type of beta-lactoglobulin showed greater body weights and measurements and gestation length than the AA or BB type, indicating an overdominance effect. Heifers with AB type of beta-lactoglobulin were significantly younger at first conception and at first freshening and had fewer number of days from first service to conception than the AA or BB type, indicating underdominance effect. Thus, beta-lactoglobulin locus shows overdominance, underdominance, or no dominance, depending upon the traits considered. The four milk protein loci contributed more dominance variance than additive variance to total phenotypic variance. This might account for the existence of milk protein polymorphism in the cattle population. The combined genotypes of the four milk protein loci showed significant effects on 2 of 14 traits studied.

  13. [Effects of population density and culture volume on the growth and reproduction of Moina irrasa].

    PubMed

    Chen, Li-Na; Li, Yu-Ying; Deng, Dao-Gui; Jin, Xian-Wen; Ge, Qian; Wang, Shao-Qin

    2012-07-01

    A laboratory experiment was conducted to study the effects of different population density (D1 : 100 ind x L(-1), D2 : 150 ind x L(-1), D3 : 300 ind x L(-1)) and culture volume (V1: 50 mL, V2 : 100 mL, V3 : 400 mL) on the growth and reproduction of Moina irrasa at 25 degrees C. At the same culture density, the body length of the M. irrasa females at their first pregnancy, the first brood, and the total offsprings per female decreased with the increase of culture volumes, while the sex ratio (male/female) of the offsprings was in adverse. At the same culture volumes, the total offsprings per female decreased with the increase of culture density. At D1 V1, the body length of the females at their first pregnancy (0.95 +/- 0.10 mm) and the total offsprings (171.3 +/- 19.8 ind) per female were the maximum. At D3V2, the sex ratio was the maximum (0.54 +/- 0.05). Culture density, culture volume, and their interactions significantly affected the total offsprings per female and the sex ratio (P < 0.001). PMID:23173474

  14. 'Carolina' session growth, reproduction, and biomass of hydrilla in North Carolina

    SciTech Connect

    Harlan, S.M.; Davis, G.J.; Pesacreta, G.

    1984-06-01

    Certain morphological and physiological characteristics are associated with the phenomenal ability of hydrilla to invade an aquatic system, overtop more desirable native rooted aquatic species, and form very dense monospecific mats. One of these adaptations is the formation of tubers which are vegetative propagules formed at the ends of positively geotropic rhizomes (Van, Haller, and Garrard 1978). Tubers develop in the hydrosoil and thus are very resistant to all control methods. Also, hydrilla's ability to become established and photosynthesize under low light intensities is unequaled by any other submersed rooted aquatic macrophyte (Van, Haller, and Bowes 1976). Hydrilla growing in lakes in Umstead State Park in North Carolina was first identified by William Haller in 1981 and had apparently been established in the area for several years. Since its initial identification, hydrilla has been found in 18 other water bodies, all in Wake Country. Hydrilla has the potential to become a very serious problem as there are presently no effective means of halting its spreading or eradicating it after infestation occurs. For effective management in North Carolina, knowledge of the growth, reproduction, and biomass of hydrilla in North Carolina is needed. This research addresses these questions.

  15. [Effects of population density and culture volume on the growth and reproduction of Moina irrasa].

    PubMed

    Chen, Li-Na; Li, Yu-Ying; Deng, Dao-Gui; Jin, Xian-Wen; Ge, Qian; Wang, Shao-Qin

    2012-07-01

    A laboratory experiment was conducted to study the effects of different population density (D1 : 100 ind x L(-1), D2 : 150 ind x L(-1), D3 : 300 ind x L(-1)) and culture volume (V1: 50 mL, V2 : 100 mL, V3 : 400 mL) on the growth and reproduction of Moina irrasa at 25 degrees C. At the same culture density, the body length of the M. irrasa females at their first pregnancy, the first brood, and the total offsprings per female decreased with the increase of culture volumes, while the sex ratio (male/female) of the offsprings was in adverse. At the same culture volumes, the total offsprings per female decreased with the increase of culture density. At D1 V1, the body length of the females at their first pregnancy (0.95 +/- 0.10 mm) and the total offsprings (171.3 +/- 19.8 ind) per female were the maximum. At D3V2, the sex ratio was the maximum (0.54 +/- 0.05). Culture density, culture volume, and their interactions significantly affected the total offsprings per female and the sex ratio (P < 0.001).

  16. Effect of commercial grade endosulfan on growth and reproduction of the fighting fish Betta splendens.

    PubMed

    Balasubramani, A; Pandian, T J

    2014-09-01

    To study the effects of endosulfan on survival, growth and reproduction of the obligate air-breathing male heterogametic fighting fish Betta splendens, posthatchlings of the fighting fish were discretely immersed for 3 h/day during the labile period on the 2nd, 5th, and 8th day posthatching (dph) at selected concentrations of commercial grade endosulfan ranging from 175 to 1400 ng/L. The immersions at 1,400 ng/L led to 21% mortality, among the 79% of surviving fry, 80% developed into females. The endosulfan reduced the air-breathing frequency of 5- and 8-day old hatchlings, and the reduction in the frequency persisted even after a depuration period of 172 days. In the ovary of the treated females, reduced number of vitellogenic oocytes with increased vacuolar cavities was observed. In the testis of the treated males, the reduced number of spermatogonia with increased vacuolar cavities was observed. The treated male induced the female to spawn a fewer eggs, which were subsequently incubated in his smaller bubble nest. The control females attained puberty on the 138th dph and spawned 120 eggs once in every 15 days, the females, which were previously treated at 1400 ng/L, postponed puberty to the 179th dph and spawned 70 eggs once in every 32 days. During the 240-day experiment, endosulfan is found to reduce significantly the cumulative progeny production from 760 to 144, reducing significantly to 19% of the control. PMID:23225381

  17. Growth, mortality, and reproduction of Tagelus plebeius (Bivalvia: Solecurtidae) in Southeast Brazil

    NASA Astrophysics Data System (ADS)

    da Silva, Camila Fernanda; Corte, Guilherme Nascimento; Yokoyama, Leonardo Querobim; Abrahão, Jolnnye Rodrigues; Amaral, Antônia Cecília Zacagnini

    2015-03-01

    Tagelus plebeius (Lightfoot, 1786) is a stout razor clam that is economically exploited in several countries, including several local fisheries along the Brazilian coast. Despite its wide distribution and economic importance, there are few studies that have examined the population biology of this species. This study aimed to improve the current knowledge about the biology of T. plebeius by investigating its growth and mortality on a subtropical sandy beach in Southeast Brazil over a 1-year period. In addition, the reproduction of T. plebeius was analyzed through qualitative and quantitative histological analyses during the last 7 months of the study. The parameters of the von Bertalanffy growth function were estimated to be L ∞ = 74.14 mm, K = 0.52 year-1, C = 0.47, and WP = 0.94. The instantaneous mortality rate ( Z) was 2.16 year-1, and the life span was 2.58 years. We confirmed variations ( H = 651.35; P < 0.05) in the shell length over the months of the study, and the recruitment was higher—but still low—in summer. Four cohorts were observed in the distribution of shell length frequencies. The sex ratio of the population was 1:1 during the study period, and a synchronism in gonadal development and spawning was found between males and females. The high mortality ( Z) and low recruitment rates can be interpreted as reflecting that the population of T. plebeius is under a low restoration process and could be an indication that this species has an endangered status in the study area.

  18. The growth and reproduction performance of TALEN-mediated β-lactoglobulin-knockout bucks.

    PubMed

    Ge, Hengtao; Cui, Chenchen; Liu, Jun; Luo, Yan; Quan, Fusheng; Jin, Yaping; Zhang, Yong

    2016-10-01

    With the technological development of several engineered endonucleases (EENs), such as zinc-finger nucleases, transcription activator-like effector nucleases (TALENs) and CRISPR/Cas9, gene targeting by homologous recombination has been efficiently improved to generate site-specifically genetically modified livestock. However, few studies have been done to investigate the health and fertility of these animals. The purpose of the present study is to investigate if gene targeting events and a recloning procedure would affect the production traits of EEN-mediated gene targeted bucks. TALEN-mediated β-lactoglobulin (BLG) gene mono-allelic knockout (BLG (+/-)) goats and bi-allelic knockout (BLG (-/-)) buck produced by using sequential gene targeting combined with recloning in fibroblasts from BLG (+/-) buck were used to evaluate their health and fertility. Birth weight and postnatal growth of BLG (+/-) bucks were similar to the wild-type goats. None of the parameters for both fresh and frozen-thawed semen quality were significantly different in BLG (+/-) or BLG (-/-) bucks compared to their corresponding comparators. In vitro fertilization (IVF) test revealed that the proportion of IVF oocytes developing to the blastocyst stage was identical among BLG (+/-), BLG (-/-) and wild-type bucks. Conception rates of artificial insemination were respectively 42.3, 38.0 and 42.6 % for frozen-thawed semen from the BLG (+/-), BLG (-/-) and wild-type bucks. In addition, germline transmission of the targeted BLG modification was in accordance with Mendelian rules. These results demonstrated that the analyzed growth and reproductive traits were not impacted by targeting BLG gene and recloning, implicating the potential for dairy goat breeding of BLG (+/-) and BLG (-/-) bucks.

  19. The growth and reproduction performance of TALEN-mediated β-lactoglobulin-knockout bucks.

    PubMed

    Ge, Hengtao; Cui, Chenchen; Liu, Jun; Luo, Yan; Quan, Fusheng; Jin, Yaping; Zhang, Yong

    2016-10-01

    With the technological development of several engineered endonucleases (EENs), such as zinc-finger nucleases, transcription activator-like effector nucleases (TALENs) and CRISPR/Cas9, gene targeting by homologous recombination has been efficiently improved to generate site-specifically genetically modified livestock. However, few studies have been done to investigate the health and fertility of these animals. The purpose of the present study is to investigate if gene targeting events and a recloning procedure would affect the production traits of EEN-mediated gene targeted bucks. TALEN-mediated β-lactoglobulin (BLG) gene mono-allelic knockout (BLG (+/-)) goats and bi-allelic knockout (BLG (-/-)) buck produced by using sequential gene targeting combined with recloning in fibroblasts from BLG (+/-) buck were used to evaluate their health and fertility. Birth weight and postnatal growth of BLG (+/-) bucks were similar to the wild-type goats. None of the parameters for both fresh and frozen-thawed semen quality were significantly different in BLG (+/-) or BLG (-/-) bucks compared to their corresponding comparators. In vitro fertilization (IVF) test revealed that the proportion of IVF oocytes developing to the blastocyst stage was identical among BLG (+/-), BLG (-/-) and wild-type bucks. Conception rates of artificial insemination were respectively 42.3, 38.0 and 42.6 % for frozen-thawed semen from the BLG (+/-), BLG (-/-) and wild-type bucks. In addition, germline transmission of the targeted BLG modification was in accordance with Mendelian rules. These results demonstrated that the analyzed growth and reproductive traits were not impacted by targeting BLG gene and recloning, implicating the potential for dairy goat breeding of BLG (+/-) and BLG (-/-) bucks. PMID:27272006

  20. Use of an organotypic mammalian in vitro follicle growth (IVFG) assay to facilitate female reproductive toxicity screening

    PubMed Central

    Xu, Yuanming; Duncan, Francesca E.; Xu, Min; Woodruff, Teresa K.

    2015-01-01

    Screening of pharmaceutical, chemical, and environmental compounds for their effects on reproductive health relies on in vivo studies. More robust and efficient methods to assess thes effects are needed. Here we adapted and validated an organotypic in vitro follicle growth (IVFG) assay to determine the impact of compounds on markers of ovarian function. We isolated mammalian follicles and cultured them in the presence of compounds with 1) known fertotoxicity (i.e., toxicity to the reproductive system; cyclophosphamide and cisplatin); 2) no known fertotoxicity (nalbuphine); and 3) unknown fertotoxicity (Corexit EC 9500 A; CE). In each case we assayed follicle growth, hormone production, and the ability of follicle-enclosed oocytes to resume meiosis and produce a mature egg. We found that cyclophosphamide and cisplatin caused dose-dependent disruption of follicle dynamics, whereas nalbuphine did not. The reproductive toxicity of CE, an oil dispersant used heavily during the 2010 Deepwater Horizon oil spill, has never been examined in a mammalian system. We found that CE compromised follicle morphology and functional parameters. Our findings demonstrate that this IVFG assay system can be used to distinguish fertotoxic from non-toxic compounds, providing an in vitro tool for assessing effects of chemical compounds on reproductive function and health. PMID:25689754

  1. Estimation of the relationship between growth, consumption, and energy allocation in juvenile pacific cod (Gadus macrocephalus) as a function of temperature and ration

    NASA Astrophysics Data System (ADS)

    Sreenivasan, Ashwin; Heintz, Ron

    2016-10-01

    Pacific cod (Gadus macrocephalus) are generalist predators in the Gulf of Alaska (GOA), and are an important predator on other commercially important species. Efficient management of this species can benefit by knowing how these fish adapt to changing environmental conditions, with a focus on how growth and condition are affected by changes in temperature and diet. We conducted a feeding study to understand the relationship between growth, ration, and temperature, and how these factors interact to affect energy allocation strategies. Since growth and condition of juveniles can determine recruitment into the population, this study focused on growth and consumption of age 1+Pacific cod held over 4 temperature treatments (4 °C, 8 °C, 12 °C, and 16 °C) and 3 ration levels (unlimited ration, medium ration, and low ration). We also compared cellular nucleic acid (RNA/DNA) ratios, an instantaneous growth index, total-body lipid, and proximate composition between fish. At 4 °C, 8 °C, and 12 °C, fish at medium and low rations had higher growth rates relative to fish at high rations. Higher food consumption appears to negatively affect digestive ability, assimilation efficiency, and nutrient utilization. RNA/DNA was clearly correlated with growth rates at 4 °C and 8 °C, but this relationship did not hold at higher temperatures. A secondary growth study was conducted to test the reliability of the growth/consumption models derived from the main growth study. Temperature influenced energy reserves (lipid) while tissue growth (protein) was influenced by ration level. Average lipid values were higher at 4 °C than at 8 °C or 12 °C, suggesting a predisposition to heightened lipid synthesis at colder temperatures. Longer durations of warmer water temperature in the GOA could consequently affect energy allocation strategies, with dietary changes in the field potentially amplifying this effect in cold and warm years. This energy allocation strategy could be detrimental

  2. Production, reproduction, health, and growth traits in backcross Holstein × Jersey cows and their Holstein contemporaries.

    PubMed

    Bjelland, D W; Weigel, K A; Hoffman, P C; Esser, N M; Coblentz, W K; Halbach, T J

    2011-10-01

    A total of 648 purebred Holstein and 319 backcross Holstein × Jersey dairy cattle were compared for production, reproduction, health, linear type, and growth traits. Animals were born between 2003 and 2009 and were housed in the University of Wisconsin-Madison Integrated Dairy Facility. All animals had Holstein dams; lactating dams were mated to unproven Holstein sires to produce purebred (control) Holsteins or to unproven F(1) Jersey × Holstein crossbred sires to produce backcross animals, whereas nulliparous dams were mated to proven Holstein sires to produce purebred (other) Holsteins. Traits were analyzed using mixed linear models with effects of season of birth, age of dam, sire, birth year of sire, days in milk, lactation, and linear type score evaluator. Control Holsteins had greater 305-d milk yield (12,645 vs. 11,456 kg), 305-d mature equivalent milk yield (13,420 vs. 12,180 kg), peak daily milk yield (49.5 vs. 46.4 kg), total lactation milk yield (11,556 vs. 10,796 kg), and daily fat-corrected milk yield (43 vs. 40 kg) compared with backcrosses. Days open and services per conception as a heifer or cow did not differ between control Holsteins, other Holsteins, or backcrosses. The proportion of first-parity births that required assistance was less in control Holsteins than in backcross cows (3.7 vs. 11.2%). The incidence of scours or respiratory problems in calves did not differ between control Holsteins, other Holsteins, and backcrosses, nor did the incidence of mastitis, injury, or feet problems. Control Holstein heifers were heavier (629 vs. 557 kg), with greater hip height (145 vs. 139 cm), body length (167 vs. 163 cm), heart girth (205 vs. 198 cm), and hip width (54 vs. 53 cm) at 22 mo of age. On a 50-point scale for linear type traits, Holsteins were larger in stature compared with backcrosses (41 vs. 28), had wider rumps (37 vs. 33), and wider rear udders (34 vs. 32). Results of this study suggest that backcross Holstein × Jersey cattle have

  3. Influence of atmospheric [CO2] on growth, carbon allocation and cost of plant tissues on leaf nitrogen concentration maintenance in nodulated Medicago sativa

    NASA Astrophysics Data System (ADS)

    Pereyra, Gabriela; Hartmann, Henrik; Ziegler, Waldemar; Michalzik, Beate; Gonzalez-Meler, Miquel; Trumbore, Susan

    2015-04-01

    Plant carbon (C) allocation and plant metabolic processes (i.e. photosynthesis and respiration) can be affected by changes in C availability, for example from changing atmospheric [CO2]. In nodulated plants, C availability may also influence nitrogen (N) fixation by bacteriods. But C allocation and N fixation are often studied independently and hence do not allow elucidating interactive effects. We investigated how different atmospheric [CO2] (Pleistocene: 170 ppm, ambient: 400 ppm and projected future: 700 ppm) influence plant growth, allocation to nodules, and the ratio of photosynthesis-to-respiration (R:A) as an indicator of C cost in Medicago sativa inoculated with Ensifer meliloti. M. sativa grew c. 38% more nodules at 400 ppm and 700 ppm than at 170 ppm. However, ratios of above- and belowground plant biomass to nodule biomass were constant over time and independent of atmospheric [CO2]. Total non-structural carbohydrate concentrations were not significantly different between plants grown at 400 and 700 ppm, but were four to five-fold higher than in 170 ppm plants. Leaf level N concentration was similar across treatments, but N-based photosynthetic rates were 82% and 93% higher in leaves of plants grown at 400 and 700 ppm, respectively, than plants grown at 170 ppm. In addition, leaf R:A was greater (48% or 55%) in plants grown at 170 ppm than plants grown at 400 and 700 ppm. Similarly, the greatest proportion of assimilated CO2 released by root respiration occurred in rhizobial plants growing at 170 ppm. Our results suggest that C limitation in nodulated Medicago sativa plants did not influence C allocation to nodule biomass but caused a proportionally greater allocation of C to belowground respiration, most likely to bacteriods. This suggests that N tissue concentration was maintained at low [CO2] by revving up bacteriod metabolism and at the expense of non-structural carbohydrate reserves.

  4. The Effect of Latitudinal Variation on Shrimp Reproductive Strategies.

    PubMed

    van de Kerk, Madelon; Jones Littles, Chanda; Saucedo, Omar; Lorenzen, Kai

    2016-01-01

    Reproductive strategies comprise the timing and frequency of reproductive events and the number of offspring per reproductive event, depending on factors such as climate conditions. Therefore, species that exhibit plasticity in the allocation of reproductive effort can alter their behavior in response to climate change. Studying how the reproductive strategy of species varies along the latitudinal gradient can help us understand and predict how they will respond to climate change. We investigated the effects of the temporal allocation of reproductive effort on the population size of brown shrimp (Farfantepenaeus aztecus) along a latitudinal gradient. Multiple shrimp species exhibit variation in their reproductive strategies, and given the economic importance of brown shrimp to the commercial fishing sector of the Unites States, changes in the timing of their reproduction could have significant economic and social consequences. We used a stage-based, density-dependent matrix population model tailored to the life history of brown shrimp. Shrimp growth rates and environmental carrying capacity were varied based on the seasonal climate conditions at different latitudes, and we estimated the population size at equilibrium. The length of the growing season increased with decreasing latitude and the reproductive strategy leading to the highest population size changed from one annual birth pulse with high reproductive output to continuous low-output reproduction. Hence, our model confirms the classical paradigm of continuous reproduction at low latitudes, with increased seasonality of the breeding period towards the poles. Our results also demonstrate the potential for variation in climate to affect the optimal reproductive strategy for achieving maximum population sizes. Certainly, understanding these dynamics may inform more comprehensive management strategies for commercially important species like brown shrimp.

  5. The Effect of Latitudinal Variation on Shrimp Reproductive Strategies

    PubMed Central

    van de Kerk, Madelon; Jones Littles, Chanda; Saucedo, Omar; Lorenzen, Kai

    2016-01-01

    Reproductive strategies comprise the timing and frequency of reproductive events and the number of offspring per reproductive event, depending on factors such as climate conditions. Therefore, species that exhibit plasticity in the allocation of reproductive effort can alter their behavior in response to climate change. Studying how the reproductive strategy of species varies along the latitudinal gradient can help us understand and predict how they will respond to climate change. We investigated the effects of the temporal allocation of reproductive effort on the population size of brown shrimp (Farfantepenaeus aztecus) along a latitudinal gradient. Multiple shrimp species exhibit variation in their reproductive strategies, and given the economic importance of brown shrimp to the commercial fishing sector of the Unites States, changes in the timing of their reproduction could have significant economic and social consequences. We used a stage-based, density-dependent matrix population model tailored to the life history of brown shrimp. Shrimp growth rates and environmental carrying capacity were varied based on the seasonal climate conditions at different latitudes, and we estimated the population size at equilibrium. The length of the growing season increased with decreasing latitude and the reproductive strategy leading to the highest population size changed from one annual birth pulse with high reproductive output to continuous low-output reproduction. Hence, our model confirms the classical paradigm of continuous reproduction at low latitudes, with increased seasonality of the breeding period towards the poles. Our results also demonstrate the potential for variation in climate to affect the optimal reproductive strategy for achieving maximum population sizes. Certainly, understanding these dynamics may inform more comprehensive management strategies for commercially important species like brown shrimp. PMID:27158895

  6. Resource Allocation.

    ERIC Educational Resources Information Center

    Stennett, R. G.

    A research allocation formula employed in London, Ontario elementary schools, as well as supporting data on the method, are provided in this report. Attempts to improve on the traditional methods of resource allocation in London's schools were based on two principles: (1) that need for a particular service could and should be determined…

  7. Influence of arbuscular mycorrhiza on growth and reproductive response of plants under water deficit: a meta-analysis.

    PubMed

    Jayne, Benjamin; Quigley, Martin

    2014-02-01

    Despite a large body of literature that describes the effects of arbuscular mycorrhizal colonization on plant response to water deficit, reviews of these works have been mainly in narrative form, and it is therefore difficult to quantify the magnitude of the effect. We performed a meta-analysis to examine the effect of mycorrhizal colonization on growth and yield of plants exposed to water deficit stress. Data were compared in the context of annual vs. perennial plants, herbaceous vs. woody plants, field vs. greenhouse conditions, degree of stress, functional group, regions of plant growth, and mycorrhizal and host species. We found that, in terms of biomass measurements, mycorrhizal plants have better growth and reproductive response under water stress compared to non-mycorrhizal plants. When variables such as habit, life cycle, or water stress level are considered, differences in mycorrhizal effect on plant growth between variables are observed. While growth of both annual and perennial plants is improved by symbiosis, perennials respond more favorably to colonization than annuals. Overall, our meta-analysis reveals a quantifiable corroboration of the commonly held view that, under water-deficit conditions, plants colonized by mycorrhizal fungi have better growth and reproductive response than those that are not.

  8. Reproductive and growth performance in Jin Hua pigs cloned from somatic cell nuclei and the meat quality of their offspring.

    PubMed

    Shibata, Masatoshi; Otake, Masayoshi; Tsuchiya, Seiko; Chikyu, Mikio; Horiuchi, Atsushi; Kawarasaki, Tatsuo

    2006-10-01

    Somatic cell cloning is expected to be a valuable method for conserving genetic resources in pigs. In this study, we compared the reproductive and growth performance of Jin Hua cloned pigs with that of naturally bred Jin Hua pigs. In addition, we generated offspring from the cloned sows and examined the productivity and quality of meat in the progeny. The birth weights and growth rates of somatic cell-cloned pigs were similar to those of Jin Hua pigs. The cloned pigs reached puberty very early, and this is typical of the Jin Hua breed. Furthermore, reproductive performance, in terms of traits such as gestation period, litter size, and raising rate in the cloned pigs were similar to Jin Hua pigs. Although the offspring of the cloned (OC) pigs had lower birth weights than the Jin Hua breed, the daily weight gain of the OC pigs was significantly higher, especially at the finishing stage. The carcass quality of the OC pigs had similar characteristics to the Jin Hua breed, namely thick back fat and a small loin area. Furthermore, the meat qualities of the OC pigs were similar to those of Jin Hua pigs in terms of intramuscular fat content and tenderness. These results demonstrate that cloned pigs and their offspring were similar to the Jin Hua breed in most of the growth, reproductive, and meat productive performances. This strongly suggests that pigs cloned from somatic cell nuclei have the potential to be a valuable genetic resource for breeding.

  9. Effects of lead on delta-aminolevulinic acid dehydratase activity, growth, hemoglobin content, and reproduction in Daphnia magna

    SciTech Connect

    Berglind, R.; Dave, G.; Sjoebeck, M.L.

    1985-04-01

    The effects of continuous exposure to lead for various periods and recovery in clean water on delta-aminolevulinic acid dehydratase (ALA-D) activity, hemoglobin content, growth, and reproduction were studied in Daphnia magna. Steady-state inhibition of ALA-D activity was reached within 2 days in 16, 64, and 256 micrograms Pb liter-1, but restoration in clean water was prolonged in relation to previous exposure. In spite of the inhibition of ALA-D activity hemoglobin content increased after 2 days in 16 and 24 micrograms Pb liter-1. Furthermore, hemoglobin content in previously exposed animals increased during recovery in clean water. Maximum hemoglobin content (2.9 times control value) was found after 2 days recovery of animals exposed to 64 micrograms Pb liter-1. These findings suggest that some enzyme(s) other than ALA-D in the biosynthetic pathway of hemoglobin formation is (are) more sensitive to lead. Growth, in contrast to reproduction, was stimulated by low concentrations of lead (less than 64 micrograms Pb liter-1), although in 256 micrograms Pb liter-1 growth was also significantly impaired. After 19 days the 16 and 50% reproductive impairment concentrations were less than or equal to 1 and 10 micrograms Pb liter-1, respectively.

  10. Tumour incidence, growth, reproduction and longevity in female C3H mice fed polyunsaturated ruminant-derived foodstuffs.

    PubMed

    Pennycuik, P R; Fogerty, A C; Willcox, M E; Ferris, M C; Baxter, R I; Johnson, A R

    1979-06-01

    Earlier studies with the random-bred Quackenbush mouse strain showed that human-type diets based on linoleic acid-enriched foodstuffs derived from ruminants fed protected polyunsaturated oils have no detrimental effects on growth, reproduction or longevity. Tumour incidence and time of onset of tumour development have now been studied in the inbred, tumour-prone mouse strain C3H, in addition to growth, reproduction and longevity. Mice were fed a polyunsaturated human diet, a conventional human diet, or mouse cubes. The results with C3H mice tended to confirm those with Quackenbush strain mice-growth rates and reproductive productivities were very similar in the two groups eating human diets. Mice on the conventional human diet tended to survive better to about 60 weeks of age than mice on the polyunsaturated diet or the cube diet, after which the mortality rates of the mice on the three diets were similar. The degree of unsaturation of the dietary fat had no significant effect on the incidence of tumours. The tumour incidence was about 40% which, taken in conjunction with the average age of onset (about 80 weeks), suggested that the NIV virus rather than the MMTV virus was responsible. It would appear that the high-fat human diets had no effect on the incidence of mammary tumours caused by this virus.

  11. The dynamics of reproductive rate, offspring survivorship and growth in the lined seahorse, Hippocampus erectus Perry, 1810.

    PubMed

    Lin, Qiang; Li, Gang; Qin, Geng; Lin, Junda; Huang, Liangmin; Sun, Hushan; Feng, Peiyong

    2012-04-15

    Seahorses are the vertebrate group with the embryonic development occurring within a special pouch in males. To understand the reproductive efficiency of the lined seahorse, Hippocampus erectus Perry, 1810 under controlled breeding experiments, we investigated the dynamics of reproductive rate, offspring survivorship and growth over births by the same male seahorses. The mean brood size of the 1-year old pairs in the 1(st) birth was 85.4±56.9 per brood, which was significantly smaller than that in the 6(th) birth (465.9±136.4 per brood) (P<0.001). The offspring survivorship and growth rate increased with the births. The fecundity was positively correlated with the length of brood pouches of males and trunk of females. The fecundity of 1-year old male and 2-year old female pairs was significantly higher than that from 1-year old couples (P<0.001). The brood size (552.7±150.4) of the males who mated with females that were isolated for the gamete-preparation, was larger than those (467.8±141.2) from the long-term pairs (P<0.05). Moreover, the offspring from the isolated females had higher survival and growth rates. Our results showed that the potential reproductive rate of seahorses H. erectus increased with the brood pouch development.

  12. Particle size as a modifying factor in sediment toxicity tests: Effects on growth, reproduction, and behavior in Chironomus tentans

    SciTech Connect

    Sibley, P.K.; Benoit, D.A.; Ankley, G.T.

    1995-12-31

    The potential for sediment grain size to interfere with the assessment of sublethal endpoints in sediment toxicity tests was evaluated using the midge C. tentans. Substrates, ranging in mean grain size from < 10 (clay) to 600 {micro}m, were used to evaluate growth in 2 and 10-day old larvae (10-day growth tests) and reproduction using newly hatched larvae (monitored through one complete generation). In a separate study, substrate selection behavior was evaluated using pair-wise choice experiments. Survivorship (> 85%) was not affected by grain size in any of the tests. Larval growth (10-day tests) was highest in substrates with mean grain size between 30 and 150 {micro}m, with maximum growth occurring at 75 pm. This relationship was observed for both 2 and 10 d old larvae, but was statistically significant only for 10 d old larvae. Reproductive potential (fecundity) was correlated with larval growth, being highest in smaller grain sizes (< 150 {micro}m). In pair-wise selection tests, larvae demonstrated only a slight preference (approximately 60:40) for the smaller of two particle sizes when the two substrates were supplied with equal amounts of food. However, when food was supplied to only one of the two grain sizes, larvae were significantly more abundant on the substrate containing food, independent of particle size. When the amount of available food was reduced, the proportion of larvae occurring on fed substrates declined. It is concluded that food availability is much more important than particle size in substrate selection by C. tentans, Together, the results of this study indicate that particle size can modify growth and reproductive potential in larval C. tentans and should be included in the interpretation of sediment toxicity tests results.

  13. Environmental Influences on Kelp Performance across the Reproductive Period: An Ecological Trade-Off between Gametophyte Survival and Growth?

    PubMed Central

    Mohring, Margaret B.; Kendrick, Gary A.; Wernberg, Thomas; Rule, Michael J.; Vanderklift, Mathew A.

    2013-01-01

    Most kelps (order Laminariales) exhibit distinct temporal patterns in zoospore production, gametogenesis and gametophyte reproduction. Natural fluctuations in ambient environmental conditions influence the intrinsic characteristics of gametes, which define their ability to tolerate varied conditions. The aim of this work was to document seasonal patterns in reproduction and gametophyte growth and survival of Ecklonia radiata (C. Agardh) J. Agardh in south-western Australia. These results were related to patterns in local environmental conditions in an attempt to ascertain which factors explain variation throughout the season. E. radiata was fertile (produced zoospores) for three and a half months over summer and autumn. Every two weeks during this time, gametophytes were grown in a range of temperatures (16–22°C) in the laboratory. Zoospore densities were highly variable among sample periods; however, zoospores released early in the season produced gametophytes which had greater rates of growth and survival, and these rates declined towards the end of the reproductive season. Growth rates of gametophytes were positively related to day length, with the fastest growing recruits released when the days were longest. Gametophytes consistently survived best in the lowest temperature (16°C), yet exhibited optimum growth in higher culture temperatures (20–22°C). These results suggest that E. radiata releases gametes when conditions are favourable for growth, and E. radiata gametophytes are tolerant of the range of temperatures observed at this location. E. radiata releases the healthiest gametophytes when day length and temperature conditions are optimal for better germination, growth, and sporophyte production, perhaps as a mechanism to help compete against other species for space and other resources. PMID:23755217

  14. Pseudoloma neurophilia infections in zebrafish Danio rerio: effects of stress on survival, growth, and reproduction.

    USGS Publications Warehouse

    Ramsay, J.M.; Watral, V.; Schreck, C.B.; Kent, M.L.

    2009-01-01

    Pseudoloma neurophilia (Microsporidia) is a common disease of zebrafish Danio rerio, including those used as research models. We conducted a study comprised of 4 separate experiments to determine the effects of husbandry stress on preexisting and experimental P. neurophilia infections and the subsequent effects on survival, infection onset and intensity, fish growth, and reproduction. In fish (AB strain) with preexisting infections, stress or feeding cortisol significantly increased mortality over 7 wk compared to no stress or cortisol treatment. In contrast, no mortality was observed in fish (TL strain) experimentally exposed to P. neurophilia over 10 wk. A third experiment involved experimental exposure of AB fish to P. neurophilia and exposure to crowding and handling stressors. No mortality was associated with P. neurophilia regardless of stress treatment over a period of 20 wk. However, the onset of infection occurred sooner in stress-treated fish. Stress significantly increased the mean intensity of infection (described as xenoma area/spinal cord area in histological sections) at Week 20 post-exposure (PE). In fish with preexisting infections, myositis was significantly greater in stressed and cortisol-treated fish than those not stressed. With experimental exposure of AB fish, stressed and infected groups weighed significantly less than the control group at Week 20 PE. Regarding fecundity, the number of larvae hatched at 5 d post fertilization was negatively associated with mean infection intensity among P. neurophilia-infected and stressed AB fish. These experiments are the first to show empirically that P. neurophilia can be associated with reduced weight and fecundity, and that stress can exacerbate the severity of the infection.

  15. Effect of neem seed extract on feeding, growth, survival, and reproduction of Diaprepes abbreviatus (Coleoptera: Curculionidae).

    PubMed

    Weathersbee, A A; Tang, Y Q

    2002-08-01

    A commercially available neem seed extract, Neemix 4.5, containing 4.5% azadirachtin (AZA), was assessed for biological activity against the root weevil Diaprepes abbreviatus (L.), an important exotic insect pest of Florida citrus. Laboratory bioassays against neonatal and 3-wk-old larvae fed sliced carrot treated with Neemix produced dose-dependent larval mortality and reduced fresh weights among survivors of treatments. The weight response was greater than the mortality response for both larval age groups. Neonates treated with 45 mg/liter AZA weighed 60% less than those in the control after 4 wk. Three-week-old larvae treated with 45 mg/ liter AZA weighed 30% less than those in the control after 5 wk. When neonates were exposed to insect diet incorporated with Neemix, reductions in larval survival and weight were observed at concentrations as low as 4.8 mg/liter AZA after 6 wk. Larval growth was inhibited by >97% with 42.9 mg/liter AZA in the diet. A soil drench containing 30 mg/liter AZA reduced the survival and weight gain of neonates added to potted citrus and provided protection to the roots in a greenhouse experiment. A concentration of 90 mg/liter AZA was required to provide protection of citrus roots against 4-wk-old larvae. Reproductive effects were observed when adult weevils were fed foliage treated with Neemix. The numbers of larvae hatching per egg mass were reduced by 27% and 68% at 30 and 90 mg/liter AZA, respectively. These results suggest that Neemix should be further evaluated for use in integrated pest management (IPM) programs of citrus. PMID:12216804

  16. Individual growth and reproductive behavior in a newly established population of northern snakehead (Channa argus), Potomac River, USA

    USGS Publications Warehouse

    Landis, Andrew M. Gascho; Lapointe, Nicolas W. R.; Angermeier, Paul L.

    2010-01-01

    Northern snakehead (Channa argus) were first found in the Potomac River in 2004. In 2007, we documented feeding and reproductive behavior to better understand how this species is performing in this novel environment. From April to October, we used electrofishing surveys to collect data on growth, condition, and gonad weight of adult fish. Growth rates of young were measured on a daily basis for several weeks. Mean length-at-age for Potomac River northern snakehead was lower than for fish from China, Russia, and Uzbekistan. Fish condition was above average during spring and fall, but below average in summer. Below-average condition corresponded to periods of high spawning activity. Gonadosomatic index indicated that females began spawning at the end of April and continued through August. Peak spawning occurred at the beginning of June when average temperatures reached 26°C. Larval fish growth rate, after the transition to exogenous feeding, was 2.3 (SD ± 0.7) mm (total length, TL) per day. Although Potomac River northern snakehead exhibited lower overall growth rates when compared to other populations, these fish demonstrated plasticity in timing of reproduction and rapid larval growth rates. Such life history characteristics likely contribute to the success of northern snakehead in its new environment and limit managers’ options for significant control of its invasion.

  17. The Dynamic of Annual Carbon Allocation to Wood in European Forests Is Consistent with a Combined Source-Sink Limitation of Growth: Implications on Growth Simulations in a Terrestrial Biosphere Model

    NASA Astrophysics Data System (ADS)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrêne, E.; François, C.; Soudani, K.; Ourcival, J. M.; Leadley, P.; Delpierre, N.

    2014-12-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will strongly determines the responses of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study was i) to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in four tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex and Picea abies) ii) to implement the identified key drivers in a new C allocation scheme within the CASTANEA terrestrial biosphere model (TBM). Combining field measurements and process-based simulations at 49 sites (931 site-years), our analyses revealed that the inter-site variability in C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. Our study supports the premise that European forest growth is under a complex panel of source- and sink- limitations, contradicting the simple source control implemented in most TBMs. The implementation of these combined forest growth limitations in the CASTANEA model significantly improved its performance when evaluated against independent stand growth data at the regional scale (mainland France, >103 plots). We finally discuss how the sink imitation affects the CASTANEA simulated projections of forest productivity along the 21th century, especially with respect to the expected fertilizing effect of increasing atmospheric

  18. Experimental manipulation of female reproduction demonstrates its fitness costs in kangaroos.

    PubMed

    Gélin, Uriel; Wilson, Michelle E; Coulson, Graeme; Festa-Bianchet, Marco

    2015-01-01

    When resources are scarce, female mammals should face a trade-off between lactation and other life-history traits such as growth, survival and subsequent reproduction. Kangaroos are ideal to test predictions about reproductive costs because they may simultaneously lactate and carry a young, and have indeterminate growth and a long breeding season. An earlier study in three of our five study populations prevented female eastern grey kangaroos (Macropus giganteus) from reproducing during one reproductive season by either inserting contraceptive implants or removing very small pouch young. We explored how individual and environmental variables affect the costs of reproduction over time, combining this experimental reduction of reproductive effort with multi-year monitoring of 270 marked females. Experimental manipulation should control for individual heterogeneity, revealing the costs of reproduction and their likely sources. We also examined the fitness consequences of reproductive effort and offspring sex among unmanipulated individuals to test whether sex allocation strategies affected trade-offs. Costs of reproduction included longer inter-birth intervals and lower probability of producing a young that survived to 7 months in the subsequent reproductive event. Weaning success, however, did not differ significantly between manipulated and control females. By reducing reproductive effort, manipulation appeared to increase individual condition and subsequent reproductive success. Effects of offspring sex upon subsequent reproductive success varied according to year and study population. Mothers of sons were generally more likely to have a young that survived to 7 months, compared to mothers of daughters. The fitness costs of reproduction arise from constraints in both acquisition and allocation of resources. To meet these costs, females delay subsequent parturition and may manipulate offspring sex. Reproductive tactics thus vary according to the amount of resource

  19. Beef heifer growth and reproductive performance following two levels of pasture allowance during the fall grazing period.

    PubMed

    Bailey, B L; Griggs, T C; Rayburn, E B; Krause, K M

    2014-08-01

    The objective of this study was to compare heifer growth and reproductive performance following 2 levels of stockpiled fall forage allowance of orchardgrass (30.5%) and tall fescue (14.1%). Spring-born heifers (n = 203 and BW = 246 ± 28.9 kg) of primarily Angus background were allocated to 2 grazing treatments during the fall period (November 12 to December 17 in yr 1, November 7 to January 4 in yr 2, and November 7 to January 14 in yr 3) each replicated 3 times per year for 3 yr. Treatments consisted of daily pasture DM allowance of 3.5% of BW (LO) or daily pasture DM allowance of 7.0% of BW (HI) under strip-grazing management. Throughout the winter feeding period, mixed grass-legume haylage and soybean hulls were fed. Heifers were grazed as 1 group under continuous stocking after the winter period. Heifers in the LO group gained less than heifers in the HI group during the fall grazing period (0.12 vs. 0.40 kg/d; P < 0.0001). For each 1 10 g increase in NDF/kg fall pasture (DM basis), fall ADG decreased 0.14 kg (P = 0.01). During winter feeding, ADG was 0.30 and 0.39 kg/d for LO vs. HI heifers, respectively (P = 0.0008). During the spring grazing period (April 16 to May 24 in yr 1, April 22 to May 26 in yr 2, and April 5 to May 16 in yr 3), LO heifers had numerically greater ADG than HI heifers (1.38 vs. 1.30 kg/d; P = 0.64). Hip height (122.7 vs. 121.4 cm; P = 0.0055), BCS (5.8 vs. 5.6; P = 0.0057), and BW (356 vs. 335 kg; P < 0.0001) at the end of spring grazing was greater for HI than LO heifers. Heifers in the LO group compensated with greater summer ADG than heifers in the HI group (0.74 vs. 0.66 kg/d; P = 0.03). Total ADG from treatment initiation (November) through pregnancy diagnosis (August) was greater for HI than LO heifers (0.61 vs. 0.55 kg/d; P < 0.001) as was BW at pregnancy diagnosis (415 vs. 402 kg; P = 0.0055). Percentage of heifers reaching puberty by the time of AI was 34% for both groups (P = 0.93). Percentage of heifers becoming pregnant to

  20. Sensitivity of growth and biomass allocation patterns to increasing nitrogen: a comparison between ephemerals and annuals in the Gurbantunggut Desert, north-western China

    PubMed Central

    Zhou, Xiaobing; Zhang, Yuanming; Niklas, Karl J.

    2014-01-01

    Background and Aims Biomass accumulation and allocation patterns are critical to quantifying ecosystem dynamics. However, these patterns differ among species, and they can change in response to nutrient availability even among genetically related individuals. In order to understand this complexity further, this study examined three ephemeral species (with very short vegetative growth periods) and three annual species (with significantly longer vegetative growth periods) in the Gurbantunggut Desert, north-western China, to determine their responses to different nitrogen (N) supplements under natural conditions. Methods Nitrogen was added to the soil at rates of 0, 0·5, 1·0, 3·0, 6·0 and 24·0 g N m−2 year−1. Plants were sampled at various intervals to measure relative growth rate and shoot and root dry mass. Key Results Compared with annuals, ephemerals grew more rapidly, increased shoot and root biomass with increasing N application rates and significantly decreased root/shoot ratios. Nevertheless, changes in the biomass allocation of some species (i.e. Erodium oxyrrhynchum) in response to the N treatment were largely a consequence of changes in overall plant size, which was inconsistent with an optimal partitioning model. An isometric log shoot vs. log root scaling relationship for the final biomass harvest was observed for each species and all annuals, while pooled data of three ephemerals showed an allometric scaling relationship. Conclusions These results indicate that ephemerals and annuals differ observably in their biomass allocation patterns in response to soil N supplements, although an isometric log shoot vs. log root scaling relationship was maintained across all species. These findings highlight that different life history strategies behave differently in response to N application even when interspecific scaling relationships remain nearly isometric. PMID:24287812

  1. Effects of chemical contaminants on growth, age-structure, and reproduction of Mytilus edulis complex from Puget sound, Washington.

    PubMed

    Kagley, Anna N; Kardong, Kyle E; Snider, Robert G; Casillas, Edmundo

    2014-07-01

    Bivalves are used as sentinel species to detect chemical contaminants in the marine environment, but biological effects on indigenous populations that result from chemical exposure are largely unknown. We assessed age-weight, length-weight relationships, age structure, and reproductive status (i.e. fecundity, egg size) of the blue mussel Mytilus edulis complex from six sites in central Puget Sound, Washington, and one site in the relatively pristine area of northern Puget Sound. Results of this study suggest that mussels from urban areas of Puget Sound exhibit a lower growth rate, altered population age-structure, and potential reproductive impairment as a result of exposure to chemical contaminants. These findings support the use of mussels as sentinel species to assess the biological effects of contaminants on invertebrate populations.

  2. Growth, mortality and reproduction of the blue tilapia Oreochromis aureus (Perciformes: Cichlidae) in the Aguamilpa Reservoir, Mexico.

    PubMed

    Peña Messina, Emilio; Tapia Varela, Raul; Velázquez Abunader, José Iván; Orbe Mendoza, Alma Araceli; Velazco Arce, Javier Marcial de Jesús Ruiz

    2010-12-01

    Tilapia production has increased in Aguamilpa Reservoir, in Nayarit, Mexico, in the last few years and represents a good economic activity for rural communities and the country. We determined growth parameters, mortality and reproductive aspects for 2413 specimens of blue tilapia Oreochromis aureus in this reservoir. Samples were taken monthly from July 2000 through June 2001, of which 1 371 were males and 1 042 were females. Standard length (SL) and total weight (TW) were measured in each organism. The SL/TW relationships through power models for sexes were determined. The growth parameters L infinity k, and t0 of the von Bertalanffy equation were estimated using frequency distribution of length through ELEFAN-I computer program. Finally the reproductive cycle and size of first maturity were established using morph chromatic maturity scale. The results suggested that the males and females had negative allometric growth (b < 3). Significant differences were found between SL/TW model for the sexes, suggesting separate models for males and females. Results indicate that there are no differences in growth rates between sexes; the proposed parameters were L infinity = 43.33 cm standard length, k = 0.36/year and t0 = -0.43 years. Natural and fishing mortality coefficients were 0.83/year and 1.10/year, respectively. The estimated exploitation rate (0.57/year) suggested that during the study period the fishery showed signs of overfishing. Blue tilapia reproduces year-round; the highest activity occurs from January through May and size of first maturity was 23 cm SL. We conclude that it is necessary to establish a minimum catch size in this reservoir based on the reproductive behavior of this species.

  3. Role of plants in the vegetative and reproductive growth of saprobic basidiomycetous ground fungi.

    PubMed

    Gramss, Gerhard; Bergmann, Hans

    2008-11-01

    Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbons or modify heavy-metal uptake of plants in soil remediations die back after their introduction into the target soils. Mycelia of saprobic basidiomycetes were therefore inoculated into soil samples of 1 l in glass vessels to record mycelial growth and reproduction in the immediate rhizosphere of up to 11 herbaceous plant species, or to study their responses to the separate volatiles from whole plant swards or their root balls whose emanations had been collected in 1.5-l plastic bags fixed to the glass vessels. Excess CO2 was controlled with NaOH solution. Volatiles from root balls of parsley and pea but not wheat, from unplanted soils, from the fungus-permeated, unplanted substrate soil itself, and from the rooting soil of whole wheat sward increased mycelial densities in Clitocybe sp. more than in Agaricus macrocarpus and indicated thus a higher nutrient state of the mycelia. Organic volatiles proved therefore to be a significant carbon source for certain basidiomycetes in poor natural soils. The contemporary decline in the number of basidiocarp initials to 0 to 36% in both fungi relative to the unplanted and aerated controls was caused by volatiles from rooted and unplanted soil and pointed thus to their ecological role as antibiotics, fumigants, toxins, and hormonal compounds. Aqueous extracts from root balls of wheat stimulated mycelial density and fruiting in A. macrocarpus contemporarily because of their contents in soil-derived macronutrients. They suppressed once more fruiting in the more sensitive Clitocybe sp. by active agents in the aqueous phase. Within plant rhizospheres, densities of Clitocybe sp. mycelia were stimulated in the presence of alfalfa, carrot, red clover, ryegrass, and spinach, whereas those of A. macrocarpus were halved by 7 of 10 plant species including alfalfa, red clover, ryegrass, and spinach. Mycelia of A. macrocarpus may thereby have

  4. Ewe lambs with higher breeding values for growth achieve higher reproductive performance when mated at age 8 months.

    PubMed

    Nieto, C A Rosales; Ferguson, M B; Macleay, C A; Briegel, J R; Wood, D A; Martin, G B; Thompson, A N

    2013-09-15

    We studied the relationships among growth, body composition and reproductive performance in ewe lambs with known phenotypic values for depth of eye muscle (EMD) and fat (FAT) and Australian Sheep Breeding Values for post-weaning live weight (PWT) and depth of eye muscle (PEMD) and fat (PFAT). To detect estrus, vasectomized rams were placed with 190 Merino ewe lambs when on average they were 157 days old. The vasectomized rams were replaced with entire rams when the ewe lambs were, on average, 226 days old. Lambs were weighed every week and blood was sampled on four occasions for assay of ghrelin, leptin and ß-hydroxybutyrate. Almost 90% of the lambs attained puberty during the experiment, at an average live weight of 41.4 kg and average age of 197 days. Ewe lambs with higher values for EMD (P < 0.001), FAT (P < 0.01), PWT (P < 0.001), PEMD (P < 0.05) and PFAT (P < 0.05) were more likely to achieve puberty by 251 days of age. Thirty-six percent of the lambs conceived and, at the estimated date of conception, the average live weight was 46.9 ± 0.6 kg and average age was 273 days. Fertility, fecundity and reproductive rate were positively related to PWT (P < 0.05) and thus live weight at the start of mating (P < 0.001). Reproductive performance was not correlated with blood concentrations of ghrelin, leptin or ß-hydroxybutyrate. Many ewe lambs attained puberty, as detected by vasectomized rams, but then failed to become pregnant after mating with entire rams. Nevertheless, we can conclude that in ewe lambs mated at 8 months of age, higher breeding values for growth, muscle and fat are positively correlated with reproductive performance, although the effects of breeding values and responses to live weight are highly variable.

  5. Analysis of 28 generations of selection for reproduction, growth, and carcass traits in swine.

    PubMed

    Hsu, W L; Johnson, R K

    2014-11-01

    Selection (28 generations, G) in a Large White-Landrace composite population for traits aimed at increasing live pigs born per litter (BA), with additional selection for increased 180-d weight (WT180) and longissimus muscle area (LMA) and decreased back fat (BF10) in the last 8 generations, was practiced. Objectives herein were to estimate genetic and phenotypic responses and genetic parameters (n = 1,883 to 54,174) and to investigate whether a plateau in response for BA occurred. Line 2 (L2) was selected for an index of ovulation rate and embryo survival (G0 to G11), fully formed pigs (FF) per litter (G12 to 14), and BA and pig birth weight (PBW, G15 to G19), and its control line (LC1) was selected randomly (G0 to G21). Line 4 (L4), derived from L2, and line 5 (L5), derived from LC1, at G8 were selected in 2 stages for ovulation rate and FF (G9 to G16) and BA and PBW (G17 to G19), and their control (LC6) was selected randomly. At G20, L4 and L5 were crossed to form L45, and L4 and L2 were crossed to continue L2; L2 and L45 were subsequently selected for BA, WT180, LMA, and BF10 (G21 to G28). At G21, LC1 and LC6 were reciprocally crossed to form LC16, control for L2, and LC61, control for L45. Selection in L2 and L45 was first for BA and then for other traits among pigs selected for BA. Line sizes were 40 to 60 litters by 15 to 20 sires/G. Cumulative selection differentials (CSD) were calculated. MTDFREML was used to estimate variance components, EBV, and responses. Genetic changes at G28 in L2 were 4.63 FF and 3.66 BA, with 72% (FF) and 86% (BA) of the change occurring after G11. Two-stage selection produced similar responses (P < 0.01) in FF in L4 and L5 (0.27 and 0.29 pigs/G) but a greater response in BA in L5 (0.19 vs. 0.28 pigs/G). Genetic change in L45 from G20 to G28 was 0.17 pigs/G for both FF and BA (P < 0.01). Genetic changes at G28 in L45 were 4.16 FF and 3.68 BA. Genetic correlations of reproductive and growth traits were near zero, ranging from -0

  6. Growth, population structure, and reproduction of western pond turtles (Actinemys marmorata) on the central coast of California

    USGS Publications Warehouse

    Germano, D.J.; Rathbun, G.B.

    2008-01-01

    We studied the population structure and growth of western pond turtles (Actinemys marmorata) at Vandenberg Air Force Base along the coast of central California in April 1995 and June 1996. We captured 179 individuals (115 males, 27 females) from 7 ponds during 26 days of trapping. Many turtles were adult-sized, but based on scute annuli, 74% were < 10 years of age, including many 2- to 3-year-olds. This population structure likely was due to a relatively fast growth rate, especially compared with closely related aquatic turtles in eastern North America. Mean clutch size was 5.2, but 66.7% of females were gravid, and 1 female produced 2 clutches. These reproductive data are similar to those reported for other populations in the southern portion of the species' range. Females reached reproductive maturity as early as 4 years of age. The relatively mild temperatures of California's Mediterranean climate, especially when compared to the seasonal extremes in more continental and northern regions of North America, may explain the different growth rates and population characteristics of freshwater turtles from these 2 regions of North America. ?? 2008 Chelonian Research Foundation.

  7. Carica papaya (Caricaceae): a case study into the effects of domestication on plant vegetative growth and reproduction.

    PubMed

    Niklas, Karl J; Marler, Thomas E

    2007-06-01

    Few studies have quantitatively evaluated the gender specific effects of cultivation on plant growth and reproduction. The availability of cultivated and wild populations of different genders of Carica papaya L. (Caricaceae) on Guam provided an opportunity to study these effects quantitatively. We compared the gender specific allometry of height vs. basal stem diameter (H vs. D), stem slenderness ratio (H/D), and the height at first flowering (H(fl)) of carpellate and staminate plants growing under natural conditions (N = 150 each) with those of carpellate and hermaphroditic plants (N = 250 each) from two cultivars (Sunrise and Tainung 2). These comparisons indicated that (1) wild carpellate and staminate plants are significantly taller than either gender of the two cultivars with equivalent D; (2) the scaling exponent governing the H vs. D relationship of both genders of wild plants is significantly higher than that of either cultivated gender; (3) cultivar type does not affect the H vs. D exponent, but gender expression does; (4) gender expression (but not cultivar-type) also affects H(fl) (cultivation substantially reduces carpellate plant H(fl)); and (5) the onset of sexual maturity is associated with a dramatic reversal in H/D ontogeny. Cultivation therefore has "condensed" patterns of vegetative growth in a gender specific manner, whereas gender expression alters both vegetative and reproductive growth significantly more so than does cultivar-type. PMID:21636469

  8. The effects of continuous and pulsed exposures of suspended clay on the survival, growth, and reproduction of Daphnia magna.

    PubMed

    Robinson, Sarah E; Capper, Neil A; Klaine, Stephen J

    2010-01-01

    Suspended sediments are a natural component of aquatic ecosystems, but anthropogenic activity such as land development can result in significant increases, especially after rain events. Continuous exposures of suspended clay and silt have been shown to affect growth and reproduction of Cladocera, leading to a decrease in population growth rate. The mechanism of clay toxicity in these filter-feeding organisms is clogging of the gut tract, resulting in decreased food uptake and assimilation. When placed in clean water, daphnids can purge clay from their gut and recover. In many surface waters, aquatic organisms experience episodic exposures of high concentrations of suspended solids driven by rain events. However, little is known about the consequences of pulsed exposures on individuals and populations. The objective of the present study was to characterize the effects of continuous and pulsed exposures of natural and defined clays on survival, growth, and reproduction of Daphnia magna. Two defined clays, montmorillonite and kaolinite, as well as clay isolated from the Piedmont region of South Carolina, USA, were used. Continuous exposures of clays elicited a dose dependent decrease in survival. Toxicity varied depending on clay source with montmorillonite > natural clay > kaolinite. Pulsed exposures caused a decrease in survival in a 24 h exposure of 734 mg/L kaolinite. Exposure to 73.9 mg/L also caused an increase in the time to gravidity, although there was not a corresponding decrease in neonate production over 21 d. No significant effects resulted from 12 h exposures even at 730 mg/L, almost 10 times the 24-h reproductive effects concentration. This suggests that exposure duration impacted toxicity more than exposure concentration in these pulsed exposures.

  9. Effects of a Glucocorticoid Receptor Agonist, Dexamethasone, on Fathead Minnow Reproduction, Growth, and Development.

    EPA Science Inventory

    Few studies have examined the effects of synthetic glucocorticoids on the reproductive axis of fish, despite the fact that these chemicals are therapeutically prescribed anti-inflammatory agents that are abundantly produced and consumed. To generate data to assess potential risk ...

  10. THE INFLUENCE OF MODEL TIME STEP ON THE RELATIVE SENSITIVIY OF POPULATION GROWTH RATE TO REPRODUCTION

    EPA Science Inventory

    In recent years there has been an increasing interest in using population models in environmental assessments. Matrix population models represent a valuable tool for extrapolating from life stage-specific stressor effects on survival and reproduction to effects on finite populati...

  11. Dynamics of reproductive growth of Lesquerella (Physaria fendleri) over different planting dates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetative and reproductive development information of lesquerella (Physaria fendleri), a new oilseed crop targeted for bio-products, is important to understand especially in the early commercialization stage of this new crop. We determined the effect of fall, winter, and spring planting dates over...

  12. EFFECTS OF THE HORMONAL GROWTH SUPPLEMENT TRENBOLONE ON REPRODUCTIVE ENDOCRINOLOGY OF THE FATHEAD MINNOW

    EPA Science Inventory

    As part of an ongoing effort to develop and validate a fathead minnow (Pimephales promelas) assay to detect chemicals that affect processes controlled by estrogens and androgens, we determined the effects of trenbolone on reproductive endocrinology of the fish. Trenbolone is a sy...

  13. Reproduction and progeny growth in rats fed clinoptilolite in the presence or absence of dietary cadmium

    SciTech Connect

    Pond, W.G.; Yen, J.T.

    1983-12-01

    The purposes of the experiment reported were to determine the effects of long-term ingestion of clinoptilolite on reproduction in female rats and on the postnatal development of their progeny and to ascertain whether or not clinoptilolite offers protection against the toxic effects of long-term Cd ingestion.

  14. Potential anthelmintic: D-psicose inhibits motility, growth and reproductive maturity of L1 larvae of Caenorhabditis elegans.

    PubMed

    Sato, Masashi; Kurose, Hiroyuki; Yamasaki, Toru; Izumori, Ken

    2008-04-01

    No anthelmintic sugars have yet been identified. Eight ketohexose stereoisomers (D- and L-forms of psicose, fructose, tagatose and sorbose), along with D-galactose and D-glucose, were examined for potency against L1 stage Caenorhabditis elegans fed Escherichia coli. Of the sugars, D-psicose specifically inhibited the motility, growth and reproductive maturity of the L1 stage. D-Psicose probably interferes with the nematode nutrition. The present results suggest that D-psicose, one of the rare sugars, is a potential anthelmintic.

  15. Preliminary Evaluation on the Effects of Feeds on the Growth and Early Reproductive Performance of Zebrafish (Danio rerio)

    PubMed Central

    2012-01-01

    This study evaluated the effects of several commercially available feeds and different feeding regimes on the growth and early reproductive performance of zebrafish (Danio rerio). Juvenile zebrafish (n= 20; 5.06 ± 0.69 mg) were stocked into each of 24 tanks (volume, 2 L); 3 tanks were assigned to each of 8 feeding combinations for a period of 60 d. At the end of 60 d, 2 male and 2 female fish from each tank were pooled by dietary treatment (n = 6) and used to evaluate the effects of feeding combinations on early reproductive performance. Zebrafish fed dietary treatments 3 and 7 had significantly greater weight gain than zebrafish fed diet 5. Mean spawning success was significantly greater in zebrafish fed the control diet (Artemiaonly) than in those fed diet 1. Mean hatch rates were greater in zebrafish fed the control feed and diets 1, 2, 3, 5, and 6 than zebrafish fed diet 4. Additional results suggest that female zebrafish are sexually mature after 90 d post fertilization and that fertilization rates are the limiting factor in early reproduction. PMID:23043806

  16. Variability in growth, development and reproduction of the non-native seaweed Sargassum muticum (Phaeophyceae) on the Irish west coast

    NASA Astrophysics Data System (ADS)

    Baer, Julia; Stengel, Dagmar B.

    2010-12-01

    This study compared seasonal growth, development and reproduction of the invasive brown macroalga Sargassum muticum in habitats with different wave exposure on the Irish west coast. Three field sites with different degrees of wave exposure were chosen for monthly observations to reflect different habitats that were characteristic of the Irish west coast. Growth and receptacle development differed considerably between sites. Growth and receptacle development was lower at the most sheltered site. Here, S. muticum showed signs of early fragmentation in April/May during the two years of investigation (2007 and 2008), whilst the population at an exposed site developed normally and plants grew to a maximum average length of 163 cm by July, with the onset of fragmentation in August. Sargassum muticum in a tide pool exhibited a similar seasonal growth cycle as plants at the exposed open shore site. Overall growth however was stunted, with plants reaching a maximum length of only 30-40 cm in July. Receptacle development was also inhibited at the sheltered site, with a maximum of only 10% of plants found to be fertile during spring and summer 2008, while plants at the exposed site and the tide pool exhibited 100% plant fertility by August. An extensive occurrence of the native epiphyte Pylaiella littoralis on S. muticum was noticed during field sampling at the sheltered study site which may have contributed to inhibited development of S. muticum observed in this area. Seasonal biomass production, photosynthetic activity and plant/frond ratio development were contrasted between Sargassum muticum at the open shore and the tide pool. Sargassum muticum biomass production in the tide pool was 3.5 times lower than that of plants on the open shore. Receptacle development and seasonal photosynthetic activity were similar for tide pool and open shore plants, irrespective of morphological differences. Highest photosynthetic rates (fluorescence yield, Yo) were measured during active

  17. Evaluation of the Growth Process of Infants Conceived by Assisted Reproductive Techniques at Royan Institute from Birth to 9 Months

    PubMed Central

    Kermani, Ramin Mozafari; Zoljalali, Shabnam; Kouhpayezadeh, Jalil; Nateghi, Mohammad-Reza; Shahzadehfazeli, Abolhasan; Nedaifard, Leila

    2011-01-01

    Objective Due to recent scientific progress in assisted reproductive techniques (ART), infertile couples can now become fertile. Thus, a number of infants in our country are the results of these costly interventions. This study has been undertaken to evaluate the physical growth process of different methods of ART infants by standard growth charts from birth until nine months of age. Methods This was a descriptive cross-sectional study of 333 infants conceived through ART [intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF)] at Royan Institute. A sequential, non-random sampling method in a period of 22 months was used. Their growth was assessed by measuring infants’ weight, height and head circumference, and physical examination. The growth patterns were calculated by recording the values in standard growth charts. The final analysis was done with SPSS version 16 and by using Chi-square test. Findings In comparison with growth charts, the weights of one-third of the infants were less than two standard deviations (SD) at birth and one-fourth had head circumference less than three SD at birth. Low birth weight (LBW) infants were six times more than infants of normal population. From birth to six months of age, growth abnormalities were seen in a substantial number of infants. However, at nine months of age, there was no significant difference observed between infants conceived by different methods of ART (IVF and ICSI). Conclusion Multiple births are the most important confounding factor impacting the growth process of ART infants. Multiple pregnancies can lead to low birth weight, height and head circumference, and growth abnormalities up to six months of age. This abnormality improves by increasing age of the infants. PMID:23056830

  18. Heterogeneous light supply affects growth and biomass allocation of the understory fern Diplopterygium glaucum at high patch contrast.

    PubMed

    Guo, Wei; Song, Yao-Bin; Yu, Fei-Hai

    2011-01-01

    Spatial heterogeneity in resource supply is common and responses to heterogeneous resource supply have been extensively documented in clonal angiosperms but not in pteridophytes. To test the hypotheses that clonal integration can modify responses of pteridophytes to heterogeneous resource supply and the integration effect is larger at higher patch contrast, we conducted a field experiment with three homogeneous and two heterogeneous light treatments on the rhizomatous, understory fern Diplopterygium glaucum in an evergreen broad-leaved forest in East China. In homogeneous treatments, all D. glaucum ramets in 1.5 m×1.5 m units were subjected to 10, 40 and 100% natural light, respectively. In the heterogeneous treatment of low patch contrast, ramets in the central 0.5 m×0.5 m plots of the units were subjected to 40% natural light and their interconnected ramets in the surrounding area of the units to 100%; in the heterogeneous treatment of high patch contrast, ramets in the central plots were subjected to 10% natural light and those in the surrounding area to 100%. In the homogeneous treatments, biomass and number of living ramets in the central plots decreased and number of dead ramets increased with decreasing light supply. At low contrast heterogeneous light supply did not affect performance or biomass allocation of D. glaucum in the central plots, but at high contrast it increased lamina biomass and number of living ramets older than annual and modified biomass allocation to lamina and rhizome. Thus, clonal integration can affect responses of understory ferns to heterogeneous light supply and ramets in low light patches can be supported by those in high light. The results also suggest that effects of clonal integration depend on the degree of patch contrast and a significant integration effect may be found only under a relatively high patch contrast.

  19. Effects of fluoride on screech owl reproduction: Teratological evaluation, growth, and blood chemistry in hatchlings

    USGS Publications Warehouse

    Hoffman, D.J.; Pattee, O.H.; Wiemeyer, Stanley N.

    1985-01-01

    The effects on reproduction in screech owls (Otus asio) of chronic dietary sodium fluoride administration at 0, 40, and 200 ppm were examined. Fluoride at 40 ppm resulted in a significantly smaller egg volume, while 200 ppm also resulted in lower egg weights and lengths. Day-one hatchlings in the 200 ppm group weighed almost 10% less than controls and had shorter crown-rump lengths. No gross abnormalities were apparent. Skeletal clearing and staining revealed significantly shorter tibiotarsus lengths in the 40 ppm and 200 ppm groups and a shorter radius-ulna length in the 200 ppm group. By 7 days of age, body weights and lengths did not differ from controls, but the tibiotarsus in the 200 ppm group remained shorter. No significant differences were detected in hematocrit, hemoglobin, plasma calcium or alkaline phosphatase. Plasma phosphorus levels were higher in the 40 ppm group than in controls. These results, in combination with the findings of Pattee et al. [25], revealed significant impairment of overall reproduction, suggesting that sodium fluoride could cause slight to moderate reproduction disorders in owls in fluoride-polluted areas.

  20. Long-term disruption of growth, reproduction, and behavior after embryonic exposure of zebrafish to PAH-spiked sediment.

    PubMed

    Vignet, Caroline; Devier, Marie-Hélène; Le Menach, Karyn; Lyphout, Laura; Potier, Jérémy; Cachot, Jérôme; Budzinski, Hélène; Bégout, Marie-Laure; Cousin, Xavier

    2014-12-01

    A natural sediment spiked with three individual polycyclic aromatic hydrocarbons (PAHs; pyrene, phenanthrene and benzo[a]pyrene) was used to expose zebrafish embryos and larvae during 4 days. The total PAH concentration was 4.4 μg g(-1) which is in the range found in sediment from contaminated areas. Quantification of metabolites in the larvae after exposure confirmed the actual contamination of the larvae and indicated an active metabolism especially for pyrene and benzo[a]pyrene. After a transfer in a clean medium, the larvae were reared to adulthood and evaluated for survival, growth, reproduction, and behavior. Measured endpoints revealed a late disruption of growth (appearing at 5 months) and a trend toward a lower reproductive ability. Adults of embryos exposed to sediment spiked with PAHs displayed lethargic and/or anxiety-like behaviors. This latter behavior was also identified in offspring at larval stage. All together, these effects could have detrimental consequences on fish performances and contribution to recruitment.

  1. Effects of decabromodiphenyl ether (BDE-209) on the avoidance response, survival, growth and reproduction of earthworms (Eisenia fetida).

    PubMed

    Xie, Xianchuan; Qian, Yan; Wu, Yingxin; Yin, Jun; Zhai, Jianping

    2013-04-01

    The effects of decabromodiphenyl ether (BDE-209) on avoidance response, survival, growth, and reproduction of earthworms (Eisenia fetida) were investigated under laboratory conditions using natural and artificial soils as substrate. Results showed that no significant avoidance response was observed when earthworms were exposed to 0.1-1000 mg/kg of BDE-209 for 48 h. After 28-days exposure, no significant effects on survival and growth of adult earthworms was induced by 0.1-1000 mg/kg of BDE-209 indicating the Lowest Observed Effect Level (LOEL) of BDE-209 on their survival and body weight was more than 1000 mg/kg. Except for a significant decrease in the number of juveniles per hatched cocoon in artificial soils at 1000 mg/kg of BDE-209, no significant effects on reproductive parameters (e.g. cocoon production per earthworms, weight per cocoon and cocoon hatchability) were observed. These results suggest that adult earthworms have a strong tolerance for BDE-209 exposure in soils, but a potential toxicity does exist for earthworm embryos or juveniles.

  2. Growth, reproduction and population growth of Ceriodaphnia cornuta sars and comparison of 7-day fecundity with Ceriodaphnia dubia richard

    NASA Astrophysics Data System (ADS)

    Zhuang, Dehui

    1989-06-01

    Biology of parthenogenetic females of Ceriodaphnia cornuta Sars was studied under laboratory conditions. The mean length of neonates (first-young instars) of Ceriodaphnia cornuta was found to be 0.27 mm at 25±1°C and that of the first adult instars 0.50 mm. A maximum length of 0.69 mm was attained at the 8th adult instar. The mean longevity was found to be 19.0 days for 3 preadult and 8 adult instars. Sex maturity was reached in 4.26 days. The mean number of young per brood was 6.21. The total production for each adult reached 49.7. The maximum reproduction period occurred during the 4th adult instar. At this age, the animals were 10.25 days old, and had a body length of 0.65 mm. The innate capacity for increase ( r m) was 0.40 per female per day, the net reproduction rate ( R 0) was 33.601 per generation, the mean length of a generation ( T) was 8.786 days, and the finite rate for increase (λ) was 1.492 per female per day. Comparisons using the t-test indicated that the number of eggs produced and number of broods of C. cornuta and C. dubia were not significantly different ( p>0.05) after 7 days.

  3. Growth, reproduction and possible recruitment variability in the abyssal brittle star Ophiocten hastatum (Ophiuroidea: Echinodermata) in the NE Atlantic

    NASA Astrophysics Data System (ADS)

    Gage, John D.; Anderson, Roslyn M.; Tyler, Paul A.; Chapman, Rachel; Dolan, Emily

    2004-06-01

    Growth was studied from skeletal growth markers in the cosmopolitan abyssal brittle star Ophiocten hastatm. Samples for analysis were taken at five sites located in the southern (2900 m) and central (2000 m) Rockall Trough, at ca. 3000 and 4000 m in the Porcupine Seabight, and at 4850 m on the Porcupine Abyssal Plain. Growth bands were assumed to reflect an annual cycle in skeletal growth. Band measurements on arm vertebrae, standardised to disc diameter, were used to provide size-at-age data and size-increment data that took into account overgrowth of early bands in older individuals. The Richards growth function marginally provides best fit to pooled size-at-age data, although the asymptote-less Tanaka function and the Gompertz growth function also provided good fit to size-at-age data which showed a rather linear growth pattern with little indication of a growth asymptote. Log e transformed size-increment data were linearised by applying the Ford-Walford method to approximate Gompertz growth so that growth could be compared at the five sites. Grouped linear regression and analysis of covariance showed no significant differences between growth at the sites and a common fitted regression. However, pairwise comparisons suggest growth differences with increasing bathymetric separation. Oocyte size frequencies measured from histological preparations of the gonad of specimens from the Porcupine Abyssal Plain indicate marked reproductive periodicity, with spawn-out in late winter that is likely followed by planktotrophic early development in spring with benthic settlement in summer. Although usually rare in the trawl and epibenthic sled samples, several years of successful recruitment followed by a period when recruitment was low or absent might explain size structure observed in a single unusually large sample from the Rockall Trough. This is consistent with previous observations during the late 1990s of a large population increase on the Porcupine Abyssal Plain

  4. Assessment of chronic effects of tebuconazole on survival, reproduction and growth of Daphnia magna after different exposure times.

    PubMed

    Sancho, E; Villarroel, M J; Ferrando, M D

    2016-02-01

    The effect of the fungicide tebuconazole (0.41, 0.52, 0.71 and 1.14mg/L) on survival, reproduction and growth of Daphnia magna organisms was monitored using 14 and 21 days exposure tests. A third experiment was performed by exposing D. magna to the fungicide for 14 days followed by 7 days of recovery (14+7). In order to test fungicide effects on D. magna, parameters as survival, mean whole body length, mean total number of neonates per female, mean number of broods per female, mean brood size per female, time to first brood/reproduction and intrinsic rate of natural increase (r) were used. Reproduction was seriously affected by tebuconazole. All tebuconazole concentrations tested affected the number of broods per female and day to first brood. At 14-days test, number of neonates per female and body size decreased by concentrations of tebuconazole higher than 0.52mg/L, whereas at 21-days test both parameters were affected at all the concentrations tested. Survival of the daphnids after 14 days fungicide exposure did not exhibited differences among experimental and control groups. In this experiment r value was reduced (in a 22%) when animals were exposed to concentrations of 0.71mg/L and 1.14mg/L. Survival of daphnids exposed during 21 days to 1.14mg/L declined, and the intrinsic rate of natural increase (r) decreased in a 30 % for tebuconazole concentrations higher than 0.41mg/L. Longevity of daphnids pre-exposed to tebuconazole for 14 days and 7 days in clean water did not show differences from control values and all of them survived the 21 days of the test. However, after 7 days in fungicide free medium animals were unable to restore control values for reproductive parameters and length. The maximum acceptable toxicant concentration (MATC) was calculated using the r values as parameter of evaluation. MATC estimations were 0.61mg/L and 0.46mg/L for 14 and 21 days, respectively. Results showed that the number of neonates per female was the highest sensitive

  5. The relationship between growth hormone polymorphism and growth hormone receptor genes with milk yield and reproductive performance in Holstein dairy cows

    PubMed Central

    Hadi, Z; Atashi, H; Dadpasand, M; Derakhshandeh, A; Ghahramani Seno, M. M

    2015-01-01

    The aim of this study was to investigate the potential association between growth hormone GH/AluI and growth hormone receptor GHR/AluI polymorphisms with milk yield and reproductive performances in Holstein dairy cows in Iran. Blood samples of 150 Holstein cows were collected and their genomic DNA was extracted using Gene-Fanavaran DNA extracting kit. Fragments of the 428 bp of exon 5 growth hormone (GH) gene and the 342 bp of exon 10 growth hormone receptor (GHR) gene were amplified using the polymerase chain reaction (PCR) method. PCR products were digested by the AluI restriction enzyme and electrophoresed on 3% agarose gel. Continuous and categorical data were analyzed using linear mixed models through Proc MIXED and logistic regression models through Proc GENMOD of SAS software, respectively. The results showed no relationship between the examined traits and GH/AluI or GHR/AluI genes. A significant relationship was found between GH/AluI polymorphism and dystocia, but the presence of the GH-L allele reduced the incidence of dystocia. The results suggest that the GH-LL genotype reduces dystocia probably by affecting the release of growth hormone; nevertheless, further studies will be needed to examine the relationship between dystocia and GH genotypes. PMID:27175183

  6. Growth and allocation of Douglas-fir seedlings in response to CO[sub 2], temperature, and nitrogen

    SciTech Connect

    Gillham, M.L.; Perry, D.A.; Grulke, N.E.; Winner, W.E. )

    1994-06-01

    Douglas-fir seedlings were grown, from cold-stratified seed, for 32 weeks in controlled-environment chambers. This factorial experiment had two levels each of atmospheric CO[sub 2] (350 an 700 ppm), soil temperature (13 and 17[degrees]C), and soil nitrogen (soils from 1200-m-elevation in the western Cascade Mountains of Oregon contained roughly two times as much carbon and nitrogen than soils from 900-m-elevation). Each whole plot (chamber) treatment (CO[sub 2] [times] temperature) was replicated three times. Photosynthetic photon flux density and soil temperature (at 15-cm-depth) were determined for each seedling/pot, and were analyzed as covariates. Doubled atmospheric CO[sub 2] resulted in greater biomass of seedlings grown in higher N-content soils, and +4[degrees]C soil temperature increased biomass of seedlings grown in both soils, at both levels of CO[sub 2]. Root-to-shoot ratios were greatest for seedlings grown in lower N-content soils for all treatments except +CO[sub 2] [times] +T, where they were equal. Doubled CO[sub 2] increased c-allocation belowground for trees grown in both soil types and at both temperatures. Corresponding data include seedling height and basal caliper, mass of structural compartments, and C, N, and total nonstructural carbohydrate contents of biomass compartments.

  7. CO2 and fertility affect growth and reproduction but not susceptibility to aphids in field grown Solanum ptycanthum

    SciTech Connect

    Long, T.M.

    1995-09-01

    In general, C3 annual plants respond positively in terms of growth, reproduction and biomass accrued when grown under elevated levels of atmospheric carbon dioxide. However, most studies documenting this response have been conducted in growth chambers where plants can be reared under conditions free form environmental stressors such as nutrient and water constraints, UV exposure and damage from pests. During the 1993 fieldseason, I grew 200 individuals of Solanum ptycanthum in an array of 10 outdoor, open-topped CO2 enclosures (5 @ 700 ppm CO2) at the University of Michigan Biological Station in Pellston, MI. Half of the plants were grown in a 50;50 mix of native C-horizon soil and topsoil (low fertility); the other half were grown in 100% topsoil (high-fertility). Plants were censused throughout the growing season for flower and fruit production, growth rate and degree of infestation of aphids. Fertility and CO2 both significantly affected production of flowers and fruits, but only fertility was significantly related to vegetative growth. Aphid infestation varied significantly among enclosures, but was not related to CO2 or fertility.

  8. Impact of early season apical meristem injury by gall inducing tipworm (Diptera: Cecidomyiidae) on reproductive and vegetative growth of cranberry.

    PubMed

    Tewari, S; Buonaccorsi, J P; Averill, A L

    2013-06-01

    Larvae of cranberry tipworm, Dasineura oxycoccana Johnson, disrupt early season growth of cranberry (Vaccinium macrocarpon Aiton) uprights or shoots by feeding on apical meristem tissue. A 2-yr field study was carried out at three different locations to determine the impact of tipworm feeding injury on the reproductive and vegetative growth of two cranberry cultivars ('Howes' and 'Stevens') in Massachusetts. In addition to tipworm-injured and intact control uprights, an artificial injury treatment simulating tipworm feeding was also included. Individual uprights of cranberry exhibited tolerance to natural (tipworm) and simulated apical meristem injury in the current growing season (fruit production) and results were corroborated by a greenhouse study. In the field study, weight of fruit was higher in tipworm-injured uprights as compared with intact control uprights at the sites with Howes. However, majority of injured uprights (tipworm and simulated) did not produce new growth from lateral buds (side-shoots) before the onset of dormancy. In the next growing season, fewer injured uprights resumed growth and produced flowers as compared with intact uprights at two of the three sites. We suggest that multiple-year studies focusing on whole plant response to tipworm herbivory will be required to determine the costs of chronic feeding injury over time.

  9. Growth and reproductive development from weaning through 20 months of age among breeds of bulls in subtropical Florida.

    PubMed

    Chase, C C; Chenoweth, P J; Larsen, R E; Olson, T A; Hammond, A C; Menchaca, M A; Randel, R D

    1997-02-01

    To determine the effect of breed on growth and reproductive development, weaned bulls in each of 2 yr were managed as a single group for approximately a year. In Year 1, the study group consisted of 24 Angus, 24 Brahman, 20 Hereford and 14 Senepol bulls, while in Year 2, it contained 25 Angus, 17 Brahman. 13 Romosinuano and 9 Nellore x Brahman bulls. Body and testicular growth measurements were recorded at 6-wk intervals. At approximately 1 yr of age and quarterly thereafter (4 periods), bulls were evaluated for libido, pubertal status, and GnRH-induced LH and testosterone secretion. Significant breed-by-age interactions occurred for most growth measurements. Brahman bulls (Bos indicus ) were (P < 0.05) older and heavier at puberty than Angus, Hereford, Senepol and Romosinuano bulls (Bos taurus ). Libido scores were lowest for Brahman and Nell ore x Brahman bulls (Bos indicus ). highest for Angus and Hereford bulls (temperate Bos taurus breeds) and intermediate for Senepol and Romosinuano bulls (tropical Bos taurus breeds; P < 0.05). Differences were not consistent among breeds or between years for GnRH-induced LH secretion. In both years, basal testosterone concentrations and areas under the GnRH-induced testosterone curve were higher (P < 0.05) for Angus and Hereford bulls (temperate breeds) than for Brahman, Senepol, Romosinuano and Nellore x Brahman bulls (tropical breeds). In conclusion, reproductive development of Senepol and Romosinuano bulls (tropical Bos taurus breeds) was more similar to Angus and Hereford bulls (temperate Bos taurus breeds) than to Brahman and Nellore x Brahman bulls (Bos indicus ). PMID:16728024

  10. Successful survival, growth, and reproductive potential of quagga mussels in low calcium lake water: is there uncertainty of establishment risk?

    PubMed Central

    Ruhmann, Emma K.; Acharya, Kumud; Chandra, Sudeep; Jerde, Christopher L.

    2015-01-01

    The risk of quagga mussel (Dreissena rostriformis bugensis Andrusov 1897) establishment into water-bodies of the western US has expanded the geographic concern regarding the ecological and economic impacts this species will have in aquatic ecosystems. Thresholds based on calcium concentrations, an element critical for mussel growth and physiology, have been used as a primary predictor of quagga mussel establishment success to aid management decisions. We evaluated the invasion potential of quagga mussels in low calcium waters using laboratory experiments to compare the survival, growth and reproductive potential of adult mussels held for 90 days at low (9 and 12 ppm), moderate (15 to 32 ppm) and high (72 ppm) calcium water concentrations. In conjunction with adult experiments, veliger stage survival, growth and settlement were evaluated under similar low, moderate, and high calcium water treatments. Adult mussels survived, grew and showed reproductive potential in low calcium water (12 ppm). Veligers were also able to survive, grow and settle in low calcium water. Higher levels of natural seston biomass appeared to improve adult mussel life history performance in low calcium water. Survival curve analysis predicted that 99% adult mortality could occur in <170 days at 9 ppm and 12 ppm, however water with >15 ppm could have adults surviving more than a year. The results from these bioassays provide further evidence that quagga mussels have higher risk of establishment in low calcium lakes if habitats exist that have slightly elevated calcium. These results should help emphasize the vulnerability of water-body in the 12 to 15 ppm calcium range that could potentially be at risk of establishing sustainable quagga mussel populations. Furthermore, these results provide insights into the uncertainty of using a single parameter in assigning establishment risk given the complexity of variables in specific water-bodies that influence life history performance of introduced

  11. Weed host specificity of the aphid, Aphis spiraecola: developmental and reproductive performance of aphids in relation to plant growth and leaf chemicals of the Siam weed, Chromolaena odorata.

    PubMed

    Agarwala, B K; Das, Jhuma

    2012-01-01

    Density, distribution, and nutritional quality of plants are the causal basis of host plant selection in aphids. Nutritional qualities of a plant vary according to its growth stage and also in response to seasonal variation. How host plant growth stages shape aphid performance was studied in Aphis spiraecola Patch (Homoptera: Aphididae) on the perennial Siam weed, Chromolaena odorata (L.) King and Robinson (Asterales: Asteraceae). This plant species is the preferred host in the hot and humid tropical parts of northeast and southern India. Variations in developmental and reproductive performances in apterous viviparous female aphids were recorded in relation to differences in leaf chemicals in different growth stages of C. odorata. Aphids reproduced at higher rates in the vegetative stage of C. odorata when developmental time was shortest, and fecundity was higher in a longer reproductive time. Intrinsic rate of increase and net reproductive rate were also recorded to be higher in the vegetative stage of the weed host. In the vegetative stage, leaves contained higher quantity of proteins and nitrogen, which are vital for insect reproduction. Results of this study have demonstrated that A spiraecola showed synchronization of its developmental and reproductive performances to growth stages of C. odorata, which occur in high abundance in the study area.

  12. Growth and development of Brassica genotypes differing in endogenous gibberellin content. I. Leaf and reproductive development.

    PubMed

    Zanewich, K P; Rood, S B; Williams, P H

    1990-08-01

    Leaf and reproductive development were compared in 3 rapid cycling Brassica rapa genotypes grown for 4 weeks under greenhouse conditions. The dwarf mutant, rosette (ros), is gibberellin (GA)-deficient, while the tall mutant, elongated internode (ein), has enhanced endogenous GA levels. Germination was delayed in ros and a selection of a more severe form of ros, named dormant (do), has even more retarded germination and some seeds entirely fail to germinate. Seeds of do and ros respond to exogenous GA, by rapid germination. The 3 genotypes, ros, normal and ein, displayed similar developmental sequences, although floral bud formation and subsequent floral development and anthesis were delayed in ros. Conversely, anthesis was slightly accelerated in ein. Individual leaf areas were reduced in both ros and ein relative to the normal genotype, but leaf numbers were similar in all 3 genotypes. Differences in leaf morphology (heterophylly) were also observed; the normal genotype and ein plants possessed uniform leaf shapes and relatively smooth leaf margins, although petiole length was increased in ein. The mutant ros had scalloped leaf margins and convoluted leaf blades in addition to shortened petioles. These phenotypes suggest a role for GA in the regulation of germination and reproductive and leaf development in Brassica.

  13. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others

    PubMed Central

    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J.; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype’s baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  14. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others.

    PubMed

    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  15. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others.

    PubMed

    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  16. Effects of plant growth promoting bacteria and composed organic fertilizers on the reproduction of Meloidogyne incognita and tomato growth.

    PubMed

    Siddiqui, Zaki A

    2004-11-01

    Glasshouse experiments were conducted to assess the influence of Pseudomonas fluorescens, Azotobacter chroococcum, Azospirillum brasilense and composted organic fertilizers (cow dung, horse dung, goat dung and poultry manure) alone and in combination on the multiplication of Meloidogyne incognita and growth of tomato. P. fluorescens was better at improving tomato growth and reducing galling and nematode multiplication than A. chroococcum or A. brasilense. Among composted organic fertilizers, poultry manure resulted in less galling and nematode multiplication than occurred with goat dung. However, composted goat dung was better in reducing nematode multiplication and improving plant growth than horse dung. Cow dung was the composted organic fertilizer least effective in reducing galling and nematode multiplication. Poultry manure with P. fluorescens was the best combination for the management of M. incognita on tomato but improved management of M. incognita can also be obtained if goat dung is used with P. fluorescens or poultry manure with A. chroococcum. PMID:15246448

  17. Effects of plant growth promoting bacteria and composed organic fertilizers on the reproduction of Meloidogyne incognita and tomato growth.

    PubMed

    Siddiqui, Zaki A

    2004-11-01

    Glasshouse experiments were conducted to assess the influence of Pseudomonas fluorescens, Azotobacter chroococcum, Azospirillum brasilense and composted organic fertilizers (cow dung, horse dung, goat dung and poultry manure) alone and in combination on the multiplication of Meloidogyne incognita and growth of tomato. P. fluorescens was better at improving tomato growth and reducing galling and nematode multiplication than A. chroococcum or A. brasilense. Among composted organic fertilizers, poultry manure resulted in less galling and nematode multiplication than occurred with goat dung. However, composted goat dung was better in reducing nematode multiplication and improving plant growth than horse dung. Cow dung was the composted organic fertilizer least effective in reducing galling and nematode multiplication. Poultry manure with P. fluorescens was the best combination for the management of M. incognita on tomato but improved management of M. incognita can also be obtained if goat dung is used with P. fluorescens or poultry manure with A. chroococcum.

  18. Relative growth and reproductive cycle of the date mussel Lithophaga lithophaga (Linnaeus, 1758) sampled from the Bizerte Bay (Northern Tunisia)

    NASA Astrophysics Data System (ADS)

    Kefi, Ferdaous Jaafar; Boubaker, Samir; Menif, Najoua Trigui El

    2014-09-01

    Relative growth and the reproductive cycle of the date mussel Lithophaga lithophaga were studied from September 2002 to October 2003 in the Bizerte Bay (Northern Tunisia). Relationships between shell length and shell width, shell height as well as volume-related variables (shell dry weight, soft tissues dry weight and total wet weight) showed negative allometries in both sexes except for shell width in males (isometry) and shell height in both sexes (positive allometry). The sex ratio was unbalanced, within the length range of 6-48 mm, 49.43 % of the animals were males, 24.39 % females and 26.17 % sexually undifferentiated; within the length range of 49-92 mm, the respective values were 41.19, 52.7 and 6.1 %. Histological investigations as well as analyses of the condition index and the gonadosomatic index (CI and GSI) revealed the presence of a single reproductive cycle per year. Spawning occurred at the end of August and early September and was associated with a decrease in seawater temperature and salinity. A resting phase occurred in winter, coinciding with the lowest water temperatures. Histological examinations of the gonads of a total of 130 specimens revealed only two cases of hermaphroditism. The present study constitutes a useful baseline for a sustainable management of local wild stocks of L. lithophaga.

  19. The growth of vegetative and reproductive structures (leaves and silks) respond similarly to hydraulic cues in maize.

    PubMed

    Turc, Olivier; Bouteillé, Marie; Fuad-Hassan, Avan; Welcker, Claude; Tardieu, François

    2016-10-01

    The elongation of styles and stigma (silks) of maize (Zea mays) flowers is rapid (1-3 mm h(-1) ), occurs over a short period and plays a pivotal role in reproductive success in adverse environments. Silk elongation rate was measured using displacement transducers in 350 plants of eight genotypes during eight experiments with varying evaporative demand and soil water status. Measured time courses revealed that silk elongation rate closely followed changes in soil water status and evaporative demand, with day-night alternations similar to those in leaves. Day-night alternations were steeper with high than with low plant transpiration rate, manipulated via evaporative demand or by covering part of the leaf area. Half times of changes in silk elongation rate upon changes in evaporative demand or soil water status were 10-30 min, similar to those in leaves. The sensitivity of silk elongation rate to xylem water potential was genetically linked to that of leaf elongation rate. Lines greatly differed for these sensitivities. These results are consistent with a common hydraulic control of expansive growth in vegetative and reproductive structures upon changes in environmental conditions via a close connection with the xylem water potential. They have important implications for breeding, modelling and phenotyping. PMID:27400762

  20. Sexual systems and dwarf males in barnacles: integrating life history and sex allocation theories.

    PubMed

    Yamaguchi, Sachi; Yusa, Yoichi; Sawada, Kota; Takahashi, Satoshi

    2013-03-01

    Barnacles, which are sedentary marine crustaceans, have diverse sexual systems that include simultaneous hermaphroditism, androdioecy (coexistence of hermaphrodites and males) and dioecy (females and males). In dioecious and androdioecious species, the males are very small and are thus called dwarf males. These sexual systems are defined by two factors: sex allocation of non-dwarf individuals and the presence or absence of dwarf males. We constructed an ESS model treating sex allocation and life history simultaneously to explain sexual systems in barnacles. We analyzed the evolutionarily stable size-dependent resource allocation strategy to male reproductive function, female reproductive function and growth in non-dwarf barnacles, and the ESS proportion of dwarf males, under conditions of varying mortality and food availability. Sex allocation in non-dwarf individuals (hermaphrodites or females) is affected by mate availability and the proportion of dwarf males. When hermaphrodites appear, all hermaphrodites become protandric simultaneous hermaphrodites. Furthermore, high mortality and poor resource availability favor dwarf males because of their early maturation and weakened sperm competition. In conclusion, we showed that combining sex allocation and life history theories is a useful way to understand various sexual systems in barnacles and perhaps in other organisms as well.

  1. Influence of lameness on follicular growth, ovulation, reproductive hormone concentrations and estrus behavior in dairy cows

    PubMed Central

    Morris, M.J.; Kaneko, K.; Walker, S.L.; Jones, D.N.; Routly, J.E.; Smith, R.F.; Dobson, H.

    2011-01-01

    The objective of this study was to examine the effect of a chronic stressor, lameness, on reproductive parameters. Seventy cows 30–80 days post-partum were scored for lameness and follicular phases synchronized with GnRH followed seven days later by prostaglandin (PG). Fifteen Lame animals did not respond to GnRH ovarian stimulation. Milk progesterone for 5 days prior to PG was lower in the remaining Lame cows than Healthy herdmates. Fewer Lame cows ovulated (26/37 versus 17/18; P = 0.04) and the interval from PG to ovulation was shorter in Lame cows. In Subset 1 (20 animals), the LH pulse frequency was similar in ovulating animals (Lame and Healthy) but lower in Lame non-ovulators. An LH surge always preceded ovulation but lameness did not affect the interval from PG to LH surge onset or LH surge concentrations. Before the LH surge, estradiol was lower in non-ovulating cows compared to those that ovulated and estradiol concentrations were positively correlated with LH pulse frequency. In Subset 2 (45 cows), Lame ovulating cows had a less intense estrus than Healthy cows, although Lame cows began estrus and stood-to-be-mounted earlier than Healthy cows. In conclusion, we have identified several parameters to explain poor fertility in some chronically stressed animals. From 30 to 80 days post-partum, there was a graded effect that ranged from 29% Lame cows with absence of ovarian activity, whereas another 21% Lame cows failed to express estrus or ovulate a low estrogenic follicle; in 50% cows, many reproductive parameters were unaffected by lameness. PMID:21601262

  2. Adaptation to metal-contaminated soils in populations of the moss, Ceratodon purpureus: Vegetative growth and reproductive expression

    SciTech Connect

    Jules, E.S.; Shaw, A.J. )

    1994-06-01

    Many observations suggest that morphological evolution occurs slowly in bryophytes, and this has been suggested to reflect low genetic diversity within species. Isozyme studies, however, stand in apparent contrast and have shown that bryophytes can contain high levels of genetic variability within and among populations. In light of this conflict, we tested the potential of the moss, Ceratodon purpureus, to undergo adaptive change (i.e., ecotypic differentiation) in response to soils that have been contaminated with high levels of metals for 90 years by measuring gametophytic growth and reproductive expression under experimental conditions. Variation in protonemal growth in sterile culture indicates that plants from one population growing on contaminated soil near a smelter are significantly more tolerant of zinc, cadmium, and lead than plants from uncontaminated sites. Results from a common garden experiment, in which plants were grown on soil from the smelter site, indicate that plants from near the smelter are significantly more tolerant of contaminated soils than plants from uncontaminated sites for vegetative growth. The same experiment suggests that plants from the smelter site are also more tolerant in terms of gametangial production (although we could not test this statistically). Our results demonstrate that C. purpureus has been able to undergo relatively rapid evolution in response to strong selective pressures. 29 refs., 4 figs., 5 tabs.

  3. Sexually Dimorphic Gene Expression Associated with Growth and Reproduction of Tongue Sole (Cynoglossus semilaevis) Revealed by Brain Transcriptome Analysis.

    PubMed

    Wang, Pingping; Zheng, Min; Liu, Jian; Liu, Yongzhuang; Lu, Jianguo; Sun, Xiaowen

    2016-08-26

    In this study, we performed a comprehensive analysis of the transcriptome of one- and two-year-old male and female brains of Cynoglossus semilaevis by high-throughput Illumina sequencing. A total of 77,066 transcripts, corresponding to 21,475 unigenes, were obtained with a N50 value of 4349 bp. Of these unigenes, 33 genes were found to have significant differential expression and potentially associated with growth, from which 18 genes were down-regulated and 12 genes were up-regulated in two-year-old males, most of these genes had no significant differences in expression among one-year-old males and females and two-year-old females. A similar analysis was conducted to look for genes associated with reproduction; 25 genes were identified, among them, five genes were found to be down regulated and 20 genes up regulated in two-year-old males, again, most of the genes had no significant expression differences among the other three. The performance of up regulated genes in Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was significantly different between two-year-old males and females. Males had a high gene expression in genetic information processing, while female's highly expressed genes were mainly enriched on organismal systems. Our work identified a set of sex-biased genes potentially associated with growth and reproduction that might be the candidate factors affecting sexual dimorphism of tongue sole, laying the foundation to understand the complex process of sex determination of this economic valuable species.

  4. Sexually Dimorphic Gene Expression Associated with Growth and Reproduction of Tongue Sole (Cynoglossus semilaevis) Revealed by Brain Transcriptome Analysis

    PubMed Central

    Wang, Pingping; Zheng, Min; Liu, Jian; Liu, Yongzhuang; Lu, Jianguo; Sun, Xiaowen

    2016-01-01

    In this study, we performed a comprehensive analysis of the transcriptome of one- and two-year-old male and female brains of Cynoglossus semilaevis by high-throughput Illumina sequencing. A total of 77,066 transcripts, corresponding to 21,475 unigenes, were obtained with a N50 value of 4349 bp. Of these unigenes, 33 genes were found to have significant differential expression and potentially associated with growth, from which 18 genes were down-regulated and 12 genes were up-regulated in two-year-old males, most of these genes had no significant differences in expression among one-year-old males and females and two-year-old females. A similar analysis was conducted to look for genes associated with reproduction; 25 genes were identified, among them, five genes were found to be down regulated and 20 genes up regulated in two-year-old males, again, most of the genes had no significant expression differences among the other three. The performance of up regulated genes in Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was significantly different between two-year-old males and females. Males had a high gene expression in genetic information processing, while female’s highly expressed genes were mainly enriched on organismal systems. Our work identified a set of sex-biased genes potentially associated with growth and reproduction that might be the candidate factors affecting sexual dimorphism of tongue sole, laying the foundation to understand the complex process of sex determination of this economic valuable species. PMID:27571066

  5. Sexually Dimorphic Gene Expression Associated with Growth and Reproduction of Tongue Sole (Cynoglossus semilaevis) Revealed by Brain Transcriptome Analysis.

    PubMed

    Wang, Pingping; Zheng, Min; Liu, Jian; Liu, Yongzhuang; Lu, Jianguo; Sun, Xiaowen

    2016-01-01

    In this study, we performed a comprehensive analysis of the transcriptome of one- and two-year-old male and female brains of Cynoglossus semilaevis by high-throughput Illumina sequencing. A total of 77,066 transcripts, corresponding to 21,475 unigenes, were obtained with a N50 value of 4349 bp. Of these unigenes, 33 genes were found to have significant differential expression and potentially associated with growth, from which 18 genes were down-regulated and 12 genes were up-regulated in two-year-old males, most of these genes had no significant differences in expression among one-year-old males and females and two-year-old females. A similar analysis was conducted to look for genes associated with reproduction; 25 genes were identified, among them, five genes were found to be down regulated and 20 genes up regulated in two-year-old males, again, most of the genes had no significant expression differences among the other three. The performance of up regulated genes in Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was significantly different between two-year-old males and females. Males had a high gene expression in genetic information processing, while female's highly expressed genes were mainly enriched on organismal systems. Our work identified a set of sex-biased genes potentially associated with growth and reproduction that might be the candidate factors affecting sexual dimorphism of tongue sole, laying the foundation to understand the complex process of sex determination of this economic valuable species. PMID:27571066

  6. Role of growth hormone and prolactin in the control of reproduction: what are we learning from transgenic and knock-out animals?

    PubMed

    Bartke, A

    1999-09-01

    Growth hormone (GH), insulin-like growth factor (IGF-I), and prolactin (PRL) can influence various aspects of reproductive functions in both females and males. However, the physiological role of PRL and the GH-IGF-I axis in the control of reproduction has been difficult to define, and the recent availability of knock-out (KO) animals allows re-examination of this issue. PRL-receptor (R)-KO and PRL-KO females are sterile because of luteal failure. In addition, these mice have severe deficits in the development of oocytes and early embryos. However, male fertility is not affected in the PRL-KO and in most of the PRL-R-KO animals. IGF-KO animals have an infantile reproductive system and are sterile. GH-R-KO mice can reproduce, but their breeding performance is reduced, particularly in females. These data indicate that IGF-I signaling is required for normal reproductive development and confirm the requirement for PRL for fertility in the female mouse. GH resistance leads to quantitative deficits in reproductive development and functions, but does not preclude fertility in either sex. We suspect that PRL and the GH-IGF-I axis provide partially overlapping (redundant) regulatory inputs to the hypothalamic-pituitary-gonadal axis, and consequently, targeted disruption of either signaling pathway has relatively mild consequences on many functions related to reproduction. Overexpression of heterologous or homologous GH in transgenic animals can lead to severe reproductive deficits, including female sterility in some of the lines. Studies in GH transgenics should allow the identification of mechanisms that mediate the effects of chronic overexposure to GH on reproduction.

  7. Growth and reproductive development of male piglets are more vulnerable to midgestation maternal stress than that of female piglets.

    PubMed

    Mack, L A; Lay, D C; Eicher, S D; Johnson, A K; Richert, B T; Pajor, E A

    2014-02-01

    In many mammalian species, prenatal stress masculinizes female and feminizes male offspring impairing their reproductive capacity. Regrouping gestating sows is a common, stressful production practice, but its impact on the developing pigs of the sow is not fully known. This study examined the effects of regrouping gestating sows and the administration of exogenous glucocorticoids on the growth and external reproductive morphology of pigs. At 37.2 ± 0.26 d of gestation, 6 cohorts of 18 sows (N = 108) were placed in 1 of 3 treatments: socially stable (Stable), hydrocortisone acetate (HCA), or mixed (Mixed). The HCA sows were administered 70 mg HCA, a synthetic glucocorticoid, twice daily during the 21 d experimental period. Each Mixed sow was penned with 2 companion sows (Companion) and regrouped on d 7 and 14 with 2 different Companion sows in a new pen. Stable and HCA sows were penned in treatment groups of 3 sows. Sow social rank was assessed weekly during feeding. After the 21 d experimental period, all sows were housed in gestation stalls for the duration of pregnancy. During the 21 d, Companion sows gained more weight than HCA and Mixed sows (P < 0.05) with Stable sows intermediate. High ranked sows gained more weight than middle and low ranked sows (P < 0.05). Mixed sows had greater head lesion scores than Stable and HCA sows (P < 0.05) with Companion sows intermediate. Head lesions increased with lower social rank (P < 0.001). Sow treatment did not affect farrowing rate, litter size, or sex ratio (P > 0.10). Social rank also had no effect on farrowing rate (P > 0.10), but affected total litter size (P = 0.03). High ranked sows bore and weaned more live females than low ranked sows (P < 0.05), in part due to differential preweaning mortality among female pigs (P = 0.01). Only male pigs were affected by sow treatment. Preweaning mortality was higher among male pigs from HCA than from Mixed sows (P = 0.04) with other treatments intermediate. Despite no weight

  8. Substudies on Allocation and Targeting of Funds and Services, Assessment of Student Growth, and Effects of Attrition. Technical Report #13 from the Study of the Sustaining Effects of Compensatory Education on Basic Skills.

    ERIC Educational Resources Information Center

    Hoepfner, Ralph, Ed.

    This study of Compensatory Education is divided into four parts: allocation of Title I funds and services, achievement and Compensatory Education, measurement of student growth, and the effects of attrition. Part one examines poverty concentrations to determine which schools and districts are eligible for Title I or for concentration grants. The…

  9. Effects of food concentration, animal interactions, and water volume on survival, growth, and reproduction of daphnia magna under flow-through conditions

    SciTech Connect

    LeBlanc, G.A.; Schoenfeld, D.A.; Surpreant, D.C.

    1981-10-01

    The purpose of this study is to evaluate the effects of food concentration, animal interaction, and water volume on the survival, growth, and reproduction of Daphnia magna under flow-through conditions. A response surface design was used to determine the interactive, as well as the individual, effects of the three factors. The results indicated that there were no important interactive effects of the three factors on survival, growth, or reproduction of D. magna. Individual effects of the factors on reproduction were observed. Food concentration produced a linear trend, with increasing food concentration resulting in an increase in offspring production. The number of daphnids per container produced a quadratic trend, with the maximum offspring production occurring in vessels containing approximately 14 daphnids. Water volume produced a slight linear trend, with increasing water volume resulting in an increase in offspring production.

  10. Effect of thermal stress, restricted feeding and combined stresses (thermal stress and restricted feeding) on growth and plasma reproductive hormone levels of Malpura ewes under semi-arid tropical environment.

    PubMed

    Sejian, V; Maurya, V P; Naqvi, S M K

    2011-04-01

    A study was conducted to assess the effect of thermal, nutritional and combined stresses (thermal and nutritional) on the growth, oestradiol and progesterone levels during oestrus cycles in Malpura ewes. Twenty-eight adult Malpura ewes were used in the present study. The ewes were randomly allocated into four groups, viz., GI (n=7; control), GII (n=7; thermal stress), GIII (n=7; restricted feeding) and GIV (n=7; combined stress). The animals were stall fed with a diet consisting of 60% roughage and 40% concentrate. GI and GII ewes were provided with ad libitum feeding while GIII and GIV ewes were provided with restricted feed (30% intake of GI and GII ewes) to induce nutritional insufficiency. GII and GIV ewes were kept in climatic chamber at 40°C and 55% RH for 6 h a day between 10:00 and 16:00 hours to induce thermal stress for a period of two oestrous cycles. Parameters studied were body weight, oestrus incidences, plasma oestradiol 17-β, plasma progesterone, conception rate, gestation period, lambing rate, and birth weight of lambs. The results indicate that combined stress significantly (p<0.05) reduced body weight, oestrus duration, birth weight of lambs, and oestradiol 17-β whereas significantly (p < 0.05) increased oestrus cycle length and progesterone. Furthermore, the results reveal that on comparative basis, ewes were able to better adapt in terms of growth and reproduction to restricted feeding than thermal stress. However, when restricted feeding was coupled with thermal stress it had significant (p<0.05) influence on body weight, average daily gain, oestradiol 17-β and progesterone concentrations. This showed that combined stress were more detrimental for these reproductive hormones in Malpura ewes under a hot semi-arid environment.

  11. The role of growth hormone and insulin-like growth factor I in the regulation of male reproductive function.

    PubMed

    Spiteri-Grech, J; Nieschlag, E

    1992-01-01

    Animal experiments and clinical studies on the interactions between growth hormone (GH) and the male hypothalamic-pituitary-gonadal axis have predominantly concentrated on GH and sex steroid interactions in the regulation of growth and development, or on the metabolic effects of GH. In contrast, little attention has been paid to the possible effects of GH on spermatogenesis, although the first report dealing with this topic was published almost 30 years ago. The interactions of GH and its main mediator, insulin-like growth factor I (IGF-I), with the hypothalamic-pituitary-gonadal axis, and their role in spermatogenesis have recently been investigated using in vitro systems and different animal models (mice and rats). Using Leydig and Sertoli cell cultures, complex interactions between GH/IGF-I and the gonadotropins affecting differentiated cell functions, e.g. steroidogenesis and cell division, have been demonstrated at the cellular level. In vivo studies using immature and mature hypophysectomized rats and GH-deficient mutant male mice and rats indicate that IGF-I can play an important role in the regulation of steroidogenesis and spermatogenesis. Furthermore, although follicle-stimulating hormone and luteinizing hormone are the major regulators of testicular IGF-I production, GH may play an indirect role by potentiating the actions of the gonadotropins in regulating testicular IGF-I content. A large proportion of men presenting at male-infertility clinics are diagnosed as having idiopathic infertility. Further studies are necessary to investigate whether defects associated with GH and/or IGF-I effects in the testis are the cause of male infertility in a small group of these patients.

  12. Divergence in plant and microbial allocation strategies explains continental patterns in microbial allocation and biogeochemical fluxes.

    PubMed

    Averill, Colin

    2014-10-01

    Allocation trade-offs shape ecological and biogeochemical phenomena at local to global scale. Plant allocation strategies drive major changes in ecosystem carbon cycling. Microbial allocation to enzymes that decompose carbon vs. organic nutrients may similarly affect ecosystem carbon cycling. Current solutions to this allocation problem prioritise stoichiometric tradeoffs implemented in plant ecology. These solutions may not maximise microbial growth and fitness under all conditions, because organic nutrients are also a significant carbon resource for microbes. I created multiple allocation frameworks and simulated microbial growth using a microbial explicit biogeochemical model. I demonstrate that prioritising stoichiometric trade-offs does not optimise microbial allocation, while exploiting organic nutrients as carbon resources does. Analysis of continental-scale enzyme data supports the allocation patterns predicted by this framework, and modelling suggests large deviations in soil C loss based on which strategy is implemented. Therefore, understanding microbial allocation strategies will likely improve our understanding of carbon cycling and climate.

  13. Direct and maternal genetic effects on growth, reproduction, and ultrasound traits in zebu Brahman cattle in Colombia.

    PubMed

    Martínez, R A; Dassonneville, R; Bejarano, D; Jimenez, A; Even, G; Mészáros, G; Sölkner, J

    2016-07-01

    Covariance components and genetic parameters were estimated for birth weight (BiW); adjusted weights at 4, 7, 12, and 18 mo; and ADG between 0 and 4 mo, between 4 and 7 mo, between 7 and 12 mo, and between 12 and 18 mo. Additionally, reproductive traits, calving interval, and age at first calving were analyzed, together with traits measured by ultrasound: loin eye area, deep fat mean, back fat, and rump fat. Analyses were performed using an animal model, considering the fixed effects of the farm ( = 37), year and month of birth, sex, calving number (1 to 7), season (dry and rainy seasons), region (North Coast, Andean Region, and Oriental Savannas), and conception (natural mating or AI), whereas the age of the cows at calving was considered a polynomial covariate with linear and quadratic effects. Three different models were used to find the one with the best fit for each trait: a single-trait model with an additive direct genetic effect, a single-trait model with additive direct and maternal genetic effects, and finally, a multitrait model with an additive direct genetic effect. For the growth traits, the heritability was between 0.24 and 0.47, with the lowest value for weight at 7 mo and the greatest value for BiW, and the maternal heritability was found to be between 0.15 and 0.21 but did not decrease later on. The correlation between direct and maternal effects was high and negative (-0.59 to -0.76). With ultrasound traits, a model with only direct effects was used. The heritability was between 0.13 and 0.28 for back fat and loin eye area, respectively. The heritabilities for deep fat mean and rump fat were similar, being 0.19 and 0.21, respectively. The reproductive traits showed high residual variance. In particular, the heritability of calving interval was low (0.06). The results showed that the growth traits have an important genetic component, which is a favorable indicator for obtaining improvement progress in the zebu Brahman breed for beef production in

  14. The effect of feeding dairy heifers diets with and without supplemental phosphorus on growth, reproductive efficiency, health, and lactation performance.

    PubMed

    Bjelland, D W; Weigel, K A; Hoffman, P C; Esser, N M; Coblentz, W K

    2011-12-01

    The phosphorus requirements for dairy heifers (0.20-0.35%) and endogenous concentrations (0.20-35%) of P in feeds fed to dairy heifers are similar, suggesting that the need for supplemental P in dairy heifer diets may be minimal. Because long-term P feeding studies on dairy heifers are unavailable, 183 Holstein heifers and 182 backcross Holstein × Jersey heifers were offered diets with (SP=0.40% of dry matter) and without (NP=0.30% of dry matter) supplemental P from 4 to 22 mo of age in a replicated pen design. Forty-eight pens of 8 heifers each were split evenly by breed and treatment group. Heifers were evaluated for body weight (BW), external bone/frame growth, dystocia, calf BW, reproductive efficiency, and first-lactation performance. Growth phase data were analyzed using pen-based statistical models, and lactation data were analyzed using mixed linear models with effects of season of birth, age of dam, heifer pen, sire, sire birth year, and days in milk. Heifers fed NP had similar average daily gain from 170 to 410 and from 410 to 650 d of age compared with heifers fed SP. At 22 mo of age, heifers fed NP did not differ in BW, hip height, hip width, body length, heart girth, cannon bone circumference, or pelvic area compared with heifers fed SP. Blood P concentrations between heifers fed SP or NP did not differ at 8 or 18 mo of age, and heifers fed SP excreted more P (29.2 vs. 24.2g/d) than heifers fed NP. As heifers, services per conception and age at pregnancy were not different between heifers fed NP or SP. At parturition, heifers fed NP or SP had similar dystocia scores and calves were similar in BW. Complete first-lactation data (305 d) were available for 333 primiparous cows, and cows fed NP as heifers produced similar milk, fat, and protein compared with cows fed SP as heifers. Days open, days in milk at first breeding, and services per conception also were similar for primiparous cows fed NP or SP as heifers. No growth, reproductive, or lactation

  15. [Effects of microwave irradiation and electrostatic field on the survival, growth and reproduction of Moina mongolica Daday].

    PubMed

    Zhao, Wen; Xu, Xian-Zhong; Jin, Dong; Hu, Yu-Cai

    2008-09-01

    The study showed that 2 450 MHz microwave irradiation for 35 seconds or more had significant death effects on Moina mongolica Daday. Short-term (less than 25 seconds) microwave irradiation could obviously increase the larvae number per clutch and the total fecundity over life span of the animal, with the highest fecundity under 10 seconds irradiation. Microwave irradiation could significantly prolong the life span (15.8-18 d) of M. mongolica. The short-term microwave irradiation had less effect on the development of larvae animal, but inhibited the adult growth to some degree. Impulse electromagnetic field could significantly increase the fecundity of M. mongolica, with the highest effect of 29 kV x cm(-1); while high-voltage electrostatic field had less effect on the reproduction of M. mongolica. Both high-voltage and impulse electrostatic fields had no remarkable effects on the development of larvae animal. High-voltage electrostatic field had less effect on the growth of adult animal; while impulse electromagnetic field had definite inhibition effect on it, and the inhibition effect was increased with increasing voltage. PMID:19102328

  16. Effect of temperature and irradiance on the growth and reproduction of Enteromorpha prolifera J. Ag. (Chlorophycophyta, Chlorophyceae)

    NASA Astrophysics Data System (ADS)

    Fu, Gang; Yao, Jianting; Liu, Fuli; Liu, Jidong; Wang, Xiuliang; Fu, Wandong; Li, Dapeng; Zhou, Mingjiang; Sun, Song; Duan, Delin

    2008-11-01

    Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate (SGR) of 10.47 at 25°C/40 μmol m-2s-1. Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 μm in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues.

  17. Interactive effects of pollination and heavy metals on resource allocation in Potentilla anserina L.

    SciTech Connect

    Saikkonen, K. |; Koivunen, S.; Vuorisalo, T.; Mutikainen, P. |

    1998-07-01

    The authors studied resource allocation between sexual reproduction and clonal propagation in a perennial stoloniferous clonal plant, Potentilla anserina, an obligate outcrosser. They manipulated reproductive effort of Potentilla anserina either by hand-pollinating all flowers or by preventing pollination. To test the effect of resource-limiting conditions on resource allocation and reproductive output, the authors used a control and two levels of heavy metals (copper and nickel) to limit plant growth. The experiment was conducted as a 2 {times} 3 factorial design to reveal possible interactions between reproductive manipulation and resource limitation. Heavy metals decreased the total biomass of the plants and number of flowers and ramets produced. Only 50% of the plants grown with the higher level of heavy metals produced flowers. Pollination treatment interacted significantly with the heavy-metal treatment. In the metal control and lower heavy-metal treatment, there were no significant differences in total vegetative biomass between the two pollination treatments. Costs of reproduction in terms of subsequent flowering in the later season appeared to be clear, because the number of flowers per whole plant was lower if the plants were hand-pollinated and because the proportion of flowering ramets decreased due to hand-pollination. However, flowering may also be partly hormonally controlled. In contrast, hand-pollinated plants exposed to high concentrations of heavy metals tended to have greater biomass of vegetative plant structures and higher number of flowers compared to nonpollinated plants.

  18. Genetic correlations between visual slaughter conformation scores and growth and reproductive traits in Canchim cattle.

    PubMed

    Borba, L H F; Baldi, F; Feitosa, F L B; da Silva, L O C; Pereira, A S C; Alencar, M M

    2016-01-01

    We obtained heritability and (co)variance component estimates for slaughter conformation scores at 420 days of age (SCS420), age at calving (first, AFC; second, ASC), calving occurrence until 38 months of age (CP38), weight at 420 days of age (W420), and scrotal circumference at 420 days (SC420) in Canchim (5/8 Charolais + 3/8 Zebu) cattle. A total of 23,168 records of Canchim animals, including 12,493 females and 10,675 males, were analyzed. SCS420 indicated carcass structure, muscle development, and subcutaneous fat deposition. The slaughter conformation score of each animal was relative to the whole contemporary group; 1 corresponded to the lowest expression of the trait and 6 to the highest. Heritabilities, and genetic and residual correlation estimates between SCS420 and reproductive and weight traits, were estimated by multitrait analyses using an animal model with Bayesian inference, employing a linear model for AFC, ASC, SC420, and W420 and a threshold model for CP38 and SCS420. Heritability estimates for SCS420, AFC, ASC, CP38, W420, and SC420 were 0.11, 0.15, 0.15, 0.15, 0.30, and 0.30, respectively. Genetic correlation estimates between SCS420 and the other traits were 0.08 (AFC), 0.58 (ASC), 0.08 (CP38), 0.43 (W420), and 0.17 (SC420). Visual slaughter conformation scores respond to individual selection and can be used as selection criteria in Canchim cattle. Selection to improve sexual precocity would not be effective in improving carcass conformation and composition, and selection for animals with high breeding values for yearling weight may improve slaughter conformation at the yearling stage. PMID:27323049

  19. Reproduction, growth, and development of rats during exposure to electric fields at multiple strengths

    SciTech Connect

    Anderson, L.E. )

    1991-11-01

    A study with multiple exposure groups and large group sizes was performed to establish whether exposure to 60-Hz electric fields would result in reproductive and development toxicity. Female rats were mated, and sperm-positive animals randomly distributed among four groups: sham-exposed, or exposed to 10, 65, or 130 kV/m, 60-Hz vertical electric fields. During gestation, exposure to the higher field strengths resulted in slightly depressed weight gains of dams. Numbers ofpups per litter and pup mortality did not differ among the exposure groups. Dams exposed at 65 kV/m lost slightly more weight through the lactation period than the control group. Male pups exposed to high field strengths gained slightly less weight from 4 to 21 days of age than did sham exposed animals. At weaning, two F{sub 1} females per litter continued on the same exposure regimen, were mated at 11 weeks of age to unexposed males, and sacrificed at 20 days of gestation. Fertility and gestational weight gain of F{sub 1} females were not affected by exposure, nor was prenatal viability or fetal body weight. No significant increase in the incidence of litters with malformations was observed. Although no developmental toxicity was detected, exposures produced physical changes in the dams, evidenced as a rust-colored deposit on the muzzle and ears (chromodacryorrhea) that increased in incidence and severity at 65 and 130 kV/m. Incidence of chromodacryorrhea was not significantly different between sham-exposed rats and those exposed at 10 kV/m. 29 refs., 10 figs., 7 tabs.

  20. Effects of lanthanum and lanthanum-modified clay on growth, survival and reproduction of Daphnia magna.

    PubMed

    Lürling, Miquel; Tolman, Yora

    2010-01-01

    The novel lanthanum-modified clay water treatment technology (Phoslock seems very promising in remediation of eutrophied waters. Phoslock is highly efficient in stripping dissolved phosphorous from the water column and in intercepting phosphorous released from the sediments. The active phosphorous-sorbent in Phoslock is the Rare Earth Element lanthanum. A leachate experiment revealed that lanthanum could be released from the clay, but only in minute quantities of 0.13-2.13microgl(-1) for a worst-case Phoslock dosage of 250mgl(-1). A life-history experiment with the zooplankton grazer Daphnia magna revealed that lanthanum, up to the 1000microgl(-1) tested, had no toxic effect on the animals, but only in medium without phosphorous. In the presence of phosphorous, rhabdophane (LaPO(4).nH(2)O) formation resulted in significant precipitation of the food algae and consequently affected life-history traits. With increasing amounts of lanthanum, in the presence of phosphate, animals remained smaller, matured later, and reproduced less, resulting in lower population growth rates. Growth rates were not affected at 33microgLal(-1), but were 6% and 7% lower at 100 and 330microgl(-1), respectively, and 20% lower at 1000microgl(-1). A juvenile growth assay with Phoslock tested in the range 0-5000mgl(-1), yielded EC(50) (NOEC) values of 871 (100) and 1557 (500)mg Phoslock l(-1) for weight and length based growth rates, respectively. The results of this study show that no major detrimental effects on Daphnia are to be expected from Phoslock or its active ingredient lanthanum when applied in eutrophication control. PMID:19801159

  1. Effect of Monochromic Light-emitting Diode Light with Different Color on the Growth and Reproductive Performances of Breeder Geese

    PubMed Central

    Chang, S. C.; Lin, M. J.; Zhuang, Z. X.; Huang, S. Y.; Lin, T. Y.; Jea, Y. S.; Fan, Y. K.; Lee, T. T.

    2016-01-01

    The purpose of this study was to investigate the effect of monochromic light-emitting diode (LED) light with different color on the growth and reproductive performances of white Roman breeder geese. A randomized complete batch design was utilized for the trial, and the replicate was regarded as one batch. Twenty ganders and fifty-five dames were used in batch 1 (started on 2011/6/17 and ended on 2012/1/31), thirty ganders and eighty-four dames were used in batch 2 (started on 2012/3/23 and ended on 2012/10/26), and thirty ganders and seventy-two dames were used in batch 3 (started on 2013/3/12 and ended on 2013/12/20). Two hundred and ninety-one geese were randomly assigned to 6 rooms in an environmentally controlled house. They were randomly allotted into one of three monochromatic light treatments: Blue, red, or white. The results showed that there was no significant difference in body weight among the three lighting groups at any point throughout the experimental period. However, compared to the blue light group, significantly more eggs were produced by the red and white light groups (p<0.05). Furthermore, the laying period of the red light group was significantly longer than that of other two groups (p<0.05). In conclusion, our results suggested that red LED-light has the best effect on reproductive performance (i.e. longer laying period and higher total eggs number) at 30 lux light intensity, and is therefore a better choice for the management of breeding geese than blue or white LED-light. PMID:26954165

  2. Effect of growth rate from 6 to 16 months of age on sexual development and reproductive function in beef bulls.

    PubMed

    Brito, L F C; Barth, A D; Wilde, R E; Kastelic, J P

    2012-04-15

    Sexual development and reproductive function were studied in 22 Angus × Charolais and 17 Angus bulls from 6 to 16 mo of age. Associations of average daily gain (ADG) and body weight with ages at puberty and at maturity (satisfactory semen quality), scrotal circumference, paired-testes volume and weight, testicular vascular cone diameter and fat thickness, scrotal temperature, sperm production and morphology, and testicular histology, were determined. There were no significant correlations between cumulative average daily gain and any of the end points investigated. Body weight at various ages was negatively correlated with ages at puberty and maturity in Angus × Charolais bulls, positively correlated with paired-testes weight in Angus × Charolais and Angus bulls, and positively correlated with seminiferous tubule volume in Angus bulls (P < 0.05). Semen quality improved gradually with age and the interval between puberty and maturity (mean ± SD; 309.4 ± 29.7 and 357 ± 42 days of age) was approximately 50 days. Age, weight, scrotal circumference, and paired-testes volume were all good predictors of pubertal and mature status, with moderate to high sensitivity and specificity (71.6% to 92.4%). In summary, growth rate between 6 and 16 mo of age did not affect sexual development and reproductive function in beef bulls. However, greater body weight at various ages was associated with reduced age at puberty and maturity, and with larger testes at 16 mo of age, indicating that improved nutrition might be beneficial, but only when offered before 6 mo of age. Average daily gains of approximately 1 to 1.6 kg/day did not result in excessive fat accumulation in the scrotum, increased scrotal temperature, or reduction in sperm production and semen quality, and could be considered "safe" targets for growing beef bulls.

  3. Effect of Ocean acidification on growth, calcification and reproduction of calcifying and non-calcifying epibionts of brown algae

    NASA Astrophysics Data System (ADS)

    Saderne, V.; Wahl, M.

    2012-04-01

    Anthropogenic emissions of CO2 are leading to an acidification of the oceans of 0.4 pH units in the course of this century according to the more severe model scenarios. The excess of CO2 could notably affect the benthic communities of calcifiers and macrophytes in different aspects (photosynthesis, respiration and calcification). Seaweeds are one of the key species of nearshore benthic ecosystems of the Baltic Sea. They are the substratum of several fouling epibionts like bryozoans and tubeworms. Most of those species are bearing calcified structures and could therefore be potentially impacted by the seawater pCO2. On the other hand, the biological activity of the host may substantially modulate the pH and pCO2 conditions in the boundary layer where the epibionts live. The aim of the present study was to test the sensitivity of seaweed macrofouling communities to higher pCO2 concentration. Fragments of macroalgae Fucus serratus bearing the calcifiers Spirorbis spirorbis (Annelida) and Electra pilosa (Bryozoa) and the non-calcifier Alcyonidium gelatinosum (Bryozoa) were maintained for 30 days under three pCO2: natural 460 ± 59 µatm and enriched 1193 ± 166 µatm and 3150 ± 446 µatm. Our study showed a significant reduction of growth rates and reproduction of Spirorbis individuals at the highest pCO2. Tubeworms Juveniles exhibited enhanced calcification of 40 % when in the light compare to dark, presumably due to effect of photosynthetic and respiratory activities of the host alga. Electra colonies showed significantly improved growth rates at 1193 µatm. The overall net dissolution of the communities was significantly higher at 3150 µatm. No effect on Alcyonidium colonies growth rates was observed. Those results suggest a remarkable resistance of the algal macro-epibiontic communities to the most elevated pCO2 predicted for 2100 for open ocean (~1000 µatm) conditions. Concerns remains with regards to higher pCO2 possibly found in the future Baltic Sea.

  4. Somatotropic Signaling: Trade-Offs Between Growth, Reproductive Development, and Longevity

    PubMed Central

    Sun, Liou Y.; Longo, Valter

    2013-01-01

    Growth hormone (GH) is a key determinant of postnatal growth and plays an important role in the control of metabolism and body composition. Surprisingly, deficiency in GH signaling delays aging and remarkably extends longevity in laboratory mice. In GH-deficient and GH-resistant animals, the “healthspan” is also extended with delays in cognitive decline and in the onset of age-related disease. The role of hormones homologous to insulin-like growth factor (IGF, an important mediator of GH actions) in the control of aging and lifespan is evolutionarily conserved from worms to mammals with some homologies extending to unicellular yeast. The combination of reduced GH, IGF-I, and insulin signaling likely contributes to extended longevity in GH or GH receptor-deficient organisms. Diminutive body size and reduced fecundity of GH-deficient and GH-resistant mice can be viewed as trade-offs for extended longevity. Mechanisms responsible for delayed aging of GH-related mutants include enhanced stress resistance and xenobiotic metabolism, reduced inflammation, improved insulin signaling, and various metabolic adjustments. Pathological excess of GH reduces life expectancy in men as well as in mice, and GH resistance or deficiency provides protection from major age-related diseases, including diabetes and cancer, in both species. However, there is yet no evidence of increased longevity in GH-resistant or GH-deficient humans, possibly due to non-age-related deaths. Results obtained in GH-related mutant mice provide striking examples of mutations of a single gene delaying aging, reducing age-related disease, and extending lifespan in a mammal and providing novel experimental systems for the study of mechanisms of aging. PMID:23589828

  5. Effect of arbuscular mycorrhizal fungi on growth and on micronutrient and macronutrient uptake and allocation in olive plantlets growing under high total Mn levels.

    PubMed

    Briccoli Bati, Caterina; Santilli, Elena; Lombardo, Luca

    2015-02-01

    The reported work was designed to increase knowledge about the role of arbuscular mycorrhizal fungi (AMF) on the phytoavailability and allocation of some of the principal macroelements and microelements in young potted olive plants growing in a soil presenting high levels of manganese (Mn), taken from an experimental olive field. A greenhouse trial was performed using self-rooted cuttings of Ascolana tenera, Nocellara del Belice and Carolea cultivars inoculated or not with two mycorrhizal inocula (commercial vs native). Molecular characterization of the indigenous AMF indicated that the species found in the experimental soil were different from those present in the commercial inoculum. The important incidence of AMF on P uptake was confirmed with generally double the concentration in mycorrhizal olive plants as compared to non-mycorrhizal controls, irrespective of genotype and inocula. Furthermore, apart from promoting plant growth (from 1.7- to 5-fold), the symbiosis reduced Mn concentrations from 43 to 83%. The observed differences depended on the cultivar and the inoculum, with native AMF being more effective probably as a result of their adaptation to the experimental soil. No clear direct relationship was found between AMF inoculation and other elements analysed.

  6. Larval rearing, metamorphosis, growth and reproduction of the eolid nudibranch hermissenda crassicornis (eschscholtz, 1831) (gastropoda: opisthobranchia).

    PubMed

    Harrigan, J F; Alkon, D L

    1978-06-01

    1. Hermissenda crassicornis is a subannual nudibranch species that reproduces year-round. 2. There is a significant positive relationship between adult weight, diameter of the egg mass, estimated number of eggs per egg mass, and average number of eggs per capsule. 3. There is a planktonic veliger stage of 34 days minimum at 13 degrees -15 degrees C. 4. Larvae metamorphose on at least three species of hydroids. 5. To develop in reasonable numbers to a state competent to metamorphose veligers require a diet that includes phytoplankton of larger cell size (10-11 microm) than the commonly used Isochrysis and Monochrysis (5 microm). 6. Although Hermissenda feeds on a wide variety of sessile invertebrate species in the ocean, a diet of tunicate alone (Ciona intestinalis) promotes good growth and survival in the laboratory. 7. Egg mass deposition is initiated only after first copulation, except in the last month of life, and continues from about one-month post-metamorphosis to death, at about four months post-metamorphosis. Generation time (egg-to-egg) may be as short as 2.5 months. 8. A laboratory strain of Hermissenda is being established to provide animals of known history for research on the neural correlates of behavior. Animals, at least initially, are being selected for fast growth rate.

  7. Effects of juvenile hormone analogs on new reproductives and colony growth of Pharaoh ant (Hymenoptera: Formicidae).

    PubMed

    Lim, S P; Lee, C Y

    2005-12-01

    Two juvenile hormone analogs (JHAs), pyriproxyfen and S-methoprene, were impregnated into dried tuna fish and fed to colonies of Monomorium pharaonis (L.) at very low concentrations (1.0, 2.0, 3.0, 4.0, and 5.0 microg/ml). Its effects on the production of sexuals and colonial growth were observed. Colonies treated with pyriproxyfen yielded sexuals with physical abnormalities. Both female and male sexuals developed bulbous wings, decreased melanization, and died shortly after emergence. Sexuals emerged from colonies treated with S-methoprene did not possess anomalous characteristics. Both pyriproxyfen and S-methoprene did not have significant effects on colonial growth because of the low concentrations of the baits. A commercial bait containing 0.3% S-methoprene (Bioprene-BM) also was evaluated for its efficacy on Pharaoh's ant colonies. Results showed that Pharaoh's ant colonies succumbed to the lethal effects of S-methoprene. Colony members were reduced significantly. Production of queens also decreased significantly in treated colonies and treated queens were unable to lay eggs. JHAs are slow acting and eliminate ant colonies at a relatively slow rate. At low concentrations, pyriproxyfen recorded baffling results, i.e., bulbous wings and demelanized exoskeleton, and it is vital that further studies are initiated to solidify these findings.

  8. Growth, reproductive performance, carcass characteristics and meat quality in F1 and F2 progenies of somatic cell-cloned pigs.

    PubMed

    Adachi, Noritaka; Yamaguchi, Daisuke; Watanabe, Akiyuki; Miura, Narumi; Sunaga, Seiji; Oishi, Hitoshi; Hashimoto, Michiko; Oishi, Takatsugu; Iwamoto, Masaki; Hanada, Hirofumi; Kubo, Masanori; Onishi, Akira

    2014-04-24

    The objective of this study was to examine the health and meat production of cloned sows and their progenies in order to demonstrate the application of somatic cell cloning to the pig industry. This study compared the growth, reproductive performance, carcass characteristics and meat quality of Landrace cloned sows, F1 progenies and F2 progenies. We measured their body weight, growth rate and feed conversion and performed a pathological analysis of their anatomy to detect abnormalities. Three of the five cloned pigs were used for a growth test. Cloned pigs grew normally and had characteristics similar to those of the control purebred Landrace pigs. Two cloned gilts were bred with a Landrace boar and used for a progeny test. F1 progenies had characteristics similar to those of the controls. Two of the F1 progeny gilts were bred with a Duroc or Large White boar and used for the progeny test. F2 progenies grew normally. There were no biological differences in growth, carcass characteristics and amino acid composition among cloned sows, F1 progenies, F2 progenies and conventional pigs. The cloned sows and F1 progenies showed normal reproductive performance. No specific abnormalities were observed by pathological analysis, with the exception of periarteritis in the F1 progenies. All pigs had a normal karyotype. These results demonstrate that cloned female pigs and their progenies have similar growth, reproductive performance and carcass quality characteristics and that somatic cell cloning could be a useful technique for conserving superior pig breeds in conventional meat production.

  9. Growth and reproductive dynamics of the South American red shrimp, Pleoticus muelleri (Crustacea: Solenoceridae), from the southeastern coast of Brazil

    NASA Astrophysics Data System (ADS)

    Castilho, A. L.; Wolf, M. R.; Simões, S. M.; Bochini, G. L.; Fransozo, V.; Costa, R. C.

    2012-12-01

    The increase in the fishing fleet in southeastern Brazil and the decrease in the landings of profitable shrimp species have contributed to the incorporation of additional species into those fisheries, such as Pleoticus muelleri. The goal of the present study is to investigate the growth and reproductive dynamics of P. muelleri in the Southeastern coast of Brazil over a period of two years. Monthly collections were conducted in Ubatuba (UB) and Caraguatatuba (CA) using a commercial shrimp fishing boat equipped with “double-rig” nets. Each region was divided into 7 sampling stations up to 35 m deep. Population parameters from size frequency distributions (carapace length = CL), growth, longevity, sex ratio, and abundance of individuals in each life period (demographic class), from both sampling areas were analyzed and compared. The relationship between abiotic factors and abundance of each demographic class was assessed using a Canonical Correlation Analysis (CCorrA). A total of 19,816 individuals were collected, of which 5341 were measured, with an estimated longevity of 2.02 (UB) and 2.15 (CA) years for females and 1.80 (UB) and 1.96 (CA) years for males. There was a statistically significant bias in sex ratio toward females (Chi-square test, p < 0.05) in both regions. The CCorrA resulted in a canonical correlation coefficient of 0.32 (p < 0.00001). Both temperature and grain size composition of the sediment showed high correlation mainly with the presence of reproductive females, followed spermatophore-bearing males and recruits. In general, these demographic classes were most common in conditions of low temperature and fine sediments. These findings, as well as other studies carried out in colder regions with the same species, are consistent with the classical paradigm of lower longevity at lower latitudes. However, our results also suggest that this species maintained abiotic preference as populations located in cold temperate regions, mainly with

  10. Population dynamics of Salpa thompsoni near the Antarctic Peninsula: Growth rates and interannual variations in reproductive activity (1993-2009)

    NASA Astrophysics Data System (ADS)

    Loeb, V. J.; Santora, J. A.

    2012-04-01

    The salp Salpa thompsoni has exhibited increased abundance in high latitude portions of the Southern Ocean in recent decades and is now frequently the numerically dominant zooplankton taxon in the Antarctic Peninsula region. The abundance increase of this species in high latitude waters is believed related to ocean warming. Due to its continuous filter feeding and production of dense rapidly sinking fecal pellets S. thompsoni is considered to be an important link in the export of particulate carbon from the surface waters. Hence basic information on the life history of this component of the Antarctic marine ecosystem is essential for assessing its impact given continued climate warming. Here we cover various aspects of the life history of S. thompsoni collected in the north Antarctic Peninsula during annual austral summer surveys of the US Antarctic Marine Living Resources (AMLR) Program between 1993 and 2009. We focus on seasonal and interannual variations in the size composition and abundance of the aggregate (sexual) and solitary (asexual) stages. This information is valuable for refining components of Southern Ocean food web models that explicitly deal with size-structured and life history information on zooplankton. Intraseasonal changes in length-frequency distribution of both stages are used to estimate their growth rates. These average 0.40 mm day-1 for aggregates and 0.23 mm day-1 for solitaries; together these represent ∼7 week and ∼7.5 month generation times, respectively, and a 9 month life cycle (i.e., onset of aggregate production year 1 to aggregate production year 2). Based on the maximum lengths typically found during January-March, the life spans of the aggregate and solitary stages can reach at least ∼5 and ∼15 months, respectively. Length-frequency distributions each year reflect interannual differences in timing of the initiation and peak reproductive output. Interannual differences in the abundance of total salps and proportions of the

  11. The roles of the immune system in women's reproduction: evolutionary constraints and life history trade-offs.

    PubMed

    Abrams, Elizabeth T; Miller, Elizabeth M

    2011-01-01

    Life history theory posits that, as long as survival is assured, finite resources are available for reproduction, maintenance, and growth/storage. To maximize lifetime reproductive success, resources are subject to trade-offs both within individuals and between current and future investment. For women, reproducing is costly and time-consuming; the bulk of available resources must be allocated to reproduction at the expense of more flexible systems like immune function. When reproducing women contract infectious diseases, the resources required for immune activation can fundamentally shift the patterns of resource allocation. Adding to the complexity of the reproductive-immune trade-offs in women are the pleiotropic effects of many immune factors, which were modified to serve key roles in mammalian reproduction. In this review, we explore the complex intersections between immune function and female reproduction to situate proximate immunological processes within a life history framework. After a brief overview of the immune system, we discuss some important physiological roles of immune factors in women's reproduction and the conflicts that may arise when these factors must play dual roles. We then discuss the influence of reproductive-immune trade-offs on the patterning of lifetime reproductive success: (1) the effect of immune activation/infectious disease on the timing of life history events; (2) the role of the immune system, immune activation, and infectious disease on resource allocation within individual reproductive events, particularly pregnancy; and (3) the role of the immune system in shaping the offspring's patterns of future life history trade-offs. We close with a discussion of future directions in reproductive immunology for anthropologists.

  12. Experimentally decoupling reproductive investment from energy storage to test the functional basis of a life-history trade-off.

    PubMed

    Cox, Robert M; Lovern, Matthew B; Calsbeek, Ryan

    2014-07-01

    The ubiquitous life-history trade-off between reproduction and survival has long been hypothesized to reflect underlying energy-allocation trade-offs between reproductive investment and processes related to self-maintenance. Although recent work has questioned whether energy-allocation models provide sufficient explanations for the survival cost of reproduction, direct tests of this hypothesis are rare, especially in wild populations. This hypothesis was tested in a wild population of brown anole lizards (Anolis sagrei) using a two-step experiment. First, stepwise variation in reproductive investment was created using unilateral and bilateral ovariectomy (OVX) along with intact (SHAM) control. Next, this manipulation was decoupled from its downstream effects on energy storage by surgically ablating the abdominal fat stores from half of the females in each reproductive treatment. As predicted, unilateral OVX (intermediate reproductive investment) induced levels of growth, body condition, fat storage and breeding-season survival that were intermediate between the high levels of bilateral OVX (no reproductive investment) and the low levels of SHAM (full reproductive investment). Ablation of abdominal fat bodies had a strong and persistent effect on energy stores, but it did not influence post-breeding survival in any of the three reproductive treatments. This suggests that the energetic savings of reduced reproductive investment do not directly enhance post-breeding survival, with the caveat that only one aspect of energy storage was manipulated and OVX itself had no overall effect on post-breeding survival. This study supports the emerging view that simple energy-allocation models may often be insufficient as explanations for the life-history trade-off between reproduction and survival.

  13. Effect of milk replacer and rumen inert fat on growth and reproduction of Malpura ram lambs.

    PubMed

    Kumar, D; Bhatt, R S; Karim, S A; Naqvi, S M K

    2014-04-01

    The objective of this study was to assess the effects of milk replacer and rumen inert fat on growth, testicular development, puberty, semen production and sperm motion characteristics of ram lambs reared under intensive management in semi-arid climatic conditions. Seven-day-old male lambs of Malpura breed (n=20) were divided equally into two groups. Up to weaning, the lambs in G1 group (control) were fed concentrate, green khejri (Prosopis cineraria) leaves and cowpea (Vigna unguiculata) hay along with suckling of dams, whereas lambs in G2 group were fed reconstituted milk at 17 g/lamb per day for the 1st week and at 34 g/lamb per day from 2nd week in addition to the feed inputs given in G1. During post weaning, lambs in the G1 group were given control concentrate, whereas in G2 the control concentrate supplemented with 40 g rumen inert fat per kg of feed was offered along with dry pala (Zizyphus nummularia) and ardu (Ailanthus excelsa) leaves. BWs of lambs were recorded weekly up to 6 months of age. Ram lambs of both the groups were trained for semen collection at a weekly interval from the age of 5 months and simultaneously testicular measurements were recorded fortnightly. The feeding of milk replacer and rumen inert fat had positive (P<0.05) effects on BW, testicular length, testicular volume, semen volume, sperm concentration, mass motility, % motility, % rapid, medium or slow motile spermatozoa. However, no significant effect was observed on testicular breadth, scrotal circumference, age of puberty, sperm velocities and other CASA-derived parameters. The results of this study indicate that higher plane of nutrition in the form of milk-replacer feeding during preweaning and rumen inert fat-supplemented feed during the postweaning period to growing ram lambs enhances their growth, testicular development and semen quality.

  14. Developmental exposure to a brominated flame retardant: an assessment of effects on physiology, growth, and reproduction in a songbird, the zebra finch.

    PubMed

    Eng, Margaret L; Williams, Tony D; Elliott, John E

    2013-07-01

    Mixtures of polybrominated diphenyl ethers (PBDEs) have been widely used as additive flame retardants, and BDE-99 is one of the most predominant congeners found in the environment. BDE-99 has been reported in avian samples worldwide, yet knowledge of its toxicity to birds is minimal. We assessed the short- and long-term effects of nestling exposure to environmentally relevant levels of BDE-99 in a model passerine, the zebra finch. Early exposure to BDE-99 did not affect hematocrit, oxidative stress, or thyroid hormones in either the juvenile or adult stages, and there were no effects on chick growth or survival. BDE-99 exposure caused a dose-dependent delay in timing of reproduction, but there were no other effects on reproductive success. In zebra finches, endpoints related to reproductive behavior appear to be the most sensitive to BDE-99. However, passerines overall appear to be less sensitive than birds of prey or mammals to PBDE exposure. PMID:23603472

  15. Growth, reproduction, mortality, distribution, and biomass of freshwater drum in Lake Erie

    USGS Publications Warehouse

    Bur, Michael T.

    1984-01-01

    Predominant age-groups in the Lake Erie freshwater drum Aplodinotus grunnienspopulation were 3, 4, and 5 as determined from gill net, trap net, bottom trawl, and midwater trawl samples. Age and growth calculations indicated that females grew faster than males. However, the length-weight relation did not differ between sexes and was described by the equation: log W = −5.4383 + 3.1987 log L. Some males became sexually mature at age 2 and all were mature by age 6. Females matured 1 year later than males. Three sizes of eggs were present in ovaries; the average total number was 127,000 per female for 20 females over a length range of 270 to 478 mm. Seasonal analysis of the ovary-body weight ratio indicated that spawning extended from June to August. A total annual mortality rate of 49% for drum aged 4 through 11 was derived from catch-curve analysis. Freshwater drum were widely distributed throughout Lake Erie in 1977–1979, the greatest concentration being in the western basin. They moved into warm, shallow water (less than 10 m deep) during summer, and returned to deeper water in late fall. Summer biomass estimates for the western basin, based on systematic surveys with bottom trawls, were 9,545 t in 1977 and 2,333 t in 1978.

  16. Effect of CO/sub 2/ enrichment on growth and reproduction of wheat grown under low oxygen. [Triticum aestivum

    SciTech Connect

    Musgrave, M.E.; Scheld, H.W.; Strain, B.R.

    1987-04-01

    Two cultivars of wheat (Triticum aestivum L. cvs Sonoita and Yecoro Rojo) were grown to maturity in a Phytotron B chamber within four sub-chambers which imposed two CO/sub 2/ levels (350 or 1000 ppm) at either ambient (21%) or low oxygen (5%). Techniques of growth analysis were used to characterize changes in plant carbon budgets imposed by the gas regimes. Large increases in leaf area were seen in the low oxygen treatments, due primarily to a stimulation of tillering. No necrosis was observed in roots developing at 5% oxygen but rather root development increased dramatically. Flowering was much delayed in the low oxygen, 350 ppm carbon dioxide regime and the spikes which did develop did not mature. While one cultivar (Sonoita) did not respond to CO/sub 2/ enrichment (1000 ppm) at ambient oxygen in terms of increases in leaf area and head number, carbon dioxide enrichment overcame the low oxygen effect on flowering in both cultivars. The results demonstrate a previously unknown interaction between carbon dioxide enrichment and low oxygen as they affect reproduction and may help elucidate the nature of low-oxygen-induced infertility.

  17. Differential effects of type and quantity of leaf damage on growth, reproduction and defence of lima bean (Phaseolus lunatus L.).

    PubMed

    Blue, E; Kay, J; Younginger, B S; Ballhorn, D J

    2015-05-01

    Folivores are major plant antagonists in most terrestrial ecosystems. However, the quantitative effects of leaf area loss on multiple interacting plant traits are still little understood. We sought to contribute to filling this lack of understanding by applying different types of leaf area removal (complete leaflets versus leaflet parts) and degrees of leaf damage (0, 33 and 66%) to lima bean (Phaseolus lunatus) plants. We quantified various growth and fitness parameters including above- and belowground biomass as well as the production of reproductive structures (fruits, seeds). In addition, we measured plant cyanogenic potential (HCNp; direct chemical defence) and production of extrafloral nectar (EFN; indirect defence). Leaf damage reduced above- and belowground biomass production in general, but neither variation in quantity nor type of damage resulted in different biomass. Similarly, the number of fruits and seeds was significantly reduced in all damaged plants without significant differences between treatment groups. Seed mass, however, was affected by both type and quantity of leaf damage. Leaf area loss had no impact on HCNp, whereas production of EFN decreased with increasing damage. While EFN production was quantitatively affected by leaf area removal, the type of damage had no effect. Our study provides a thorough analysis of the quantitative and qualitative effects of defoliation on multiple productivity-related and defensive plant traits and shows strong differences in plant response depending on trait. Quantifying such plant responses is vital to our understanding of the impact of herbivory on plant fitness and productivity in natural and agricultural ecosystems.

  18. Growth and reproductive effects from dietary exposure to Aroclor 1268 in mink (Neovison vison), a surrogate model for marine mammals.

    PubMed

    Folland, William R; Newsted, John L; Fitzgerald, Scott D; Fuchsman, Phyllis C; Bradley, Patrick W; Kern, John; Kannan, Kurunthachalam; Remington, Richard E; Zwiernik, Matthew J

    2016-03-01

    Polychlorinated biphenyls (PCBs) from the commercial mixture Aroclor 1268 were historically released into the Turtle-Brunswick River estuary (southeastern Georgia, USA) from industrial operations. Sum PCBs (ΣPCBs) in blubber samples from Turtle-Brunswick River estuary bottlenose dolphins (Tursiops truncatus) have been reported at concentrations more than 10-fold higher than those observed in dolphins from adjacent regional estuaries. Given that toxicity data specific to Aroclor 1268 and applicable to marine mammals are limited, predicting the toxic effects of Aroclor 1268 in dolphins is uncertain, particularly because of its unique congener profile and associated physiochemical characteristics compared with other PCB mixtures. American mink (Neovison vison) were chosen as a surrogate model for cetaceans to develop marine mammalian PCB toxicity benchmarks. Mink are a suitable surrogate species for cetaceans in toxicity studies because of similarities in diet and taxonomic class, and a characteristic sensitivity to PCBs provides a potential safety factor when using mink toxicology data for cross-species extrapolations. Effects of dietary exposure to Aroclor 1268 on reproduction, growth, and mortality in mink were compared with both a negative control and a positive control (3,3',4,4',5-pentachlorobiphenyl, PCB 126). Aroclor 1268 dietary ΣPCB concentrations ranged from 1.8 µg/g feed wet weight to 29 µg/g feed wet weight. Whelp success was unaffected by Aroclor 1268 exposure at any level. Treatment mean litter size, kit growth, and kit survival were adversely affected relative to the negative control at dietary ΣPCB concentrations of 10.6 µg/g feed wet weight and greater. PMID:26313468

  19. Identification and genetic characterization of a gibberellin 2-oxidase gene that controls tree stature and reproductive growth in plum

    PubMed Central

    El-Sharkawy, I.; El Kayal, W.; Prasath, D.; Fernández, H.; Bouzayen, M.; Svircev, A. M.; Jayasankar, S.

    2012-01-01

    Several dwarf plum genotypes (Prunus salicina L.), due to deficiency of unknown gibberellin (GA) signalling, were identified. A cDNA encoding GA 2-oxidase (PslGA2ox), the major gibberellin catabolic enzyme in plants, was cloned and used to screen the GA-deficient hybrids. This resulted in the identification of a dwarf plum hybrid, designated as DGO24, that exhibits a markedly elevated PslGA2ox signal. Grafting ‘Early Golden’ (EG), a commercial plum cultivar, on DGO24 (EG/D) enhanced PslGA2ox accumulation in the scion part and generated trees of compact stature. Assessment of active GAs in such trees revealed that DGO24 and EG/D accumulated relatively much lower quantities of main bioactive GAs (GA1 and GA4) than control trees (EG/M). Moreover, the physiological function of PslGA2ox was studied by determining the molecular and developmental consequences due to ectopic expression in Arabidopsis. Among several lines, two groups of homozygous transgenics that exhibited contrasting phenotypes were identified. Group-1 displayed a dwarf growth pattern typical of mutants with a GA deficiency including smaller leaves, shorter stems, and delay in the development of reproductive events. In contrast, Group-2 exhibited a ‘GA overdose’ phenotype as all the plants showed elongated growth, a typical response to GA application, even under limited GA conditions, potentially due to co-suppression of closely related Arabidopsis homologous. The studies reveal the possibility of utilizing PslGA2ox as a marker for developing size-controlling rootstocks in Prunus. PMID:22080981

  20. Growth and reproduction of the alpine grasshopper Miramella alpina feeding on CO2-enriched dwarf shrubs at treeline.

    PubMed

    Asshoff, Roman; Hättenschwiler, Stephan

    2005-01-01

    The consequences for plant-insect interactions of atmospheric changes in alpine ecosystems are not well understood. Here, we tested the effects of elevated CO(2) on leaf quality in two dwarf shrub species (Vaccinium myrtillus and V. uliginosum) and the response of the alpine grasshopper (Miramella alpina) feeding on these plants in a field experiment at the alpine treeline (2,180 m a.s.l.) in Davos, Switzerland. Relative growth rates (RGR) of M. alpina nymphs were lower when they were feeding on V. myrtillus compared to V. uliginosum, and were affected by elevated CO(2) depending on plant species and nymph developmental stage. Changes in RGR correlated with CO(2)-induced changes in leaf water, nitrogen, and starch concentrations. Elevated CO(2) resulted in reduced female adult weight irrespective of plant species, and prolonged development time on V. uliginosum only, but there were no significant differences in nymphal mortality. Newly molted adults of M. alpina produced lighter eggs and less secretion (serving as egg protection) under elevated CO(2). When grasshoppers had a choice among four different plant species grown either under ambient or elevated CO(2), V. myrtillus and V. uliginosum consumption increased under elevated CO(2) in females while it decreased in males compared to ambient CO(2)-grown leaves. Our findings suggest that rising atmospheric CO(2) distinctly affects leaf chemistry in two important dwarf shrub species at the alpine treeline, leading to changes in feeding behavior, growth, and reproduction of the most important insect herbivore in this system. Changes in plant-grasshopper interactions might have significant long-term impacts on herbivore pressure, community dynamics and ecosystem stability in the alpine treeline ecotone. PMID:15480804

  1. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840).

    PubMed

    Usseglio, Paolo; Friedlander, Alan M; DeMartini, Edward E; Schuhbauer, Anna; Schemmel, Eva; Salinas de Léon, Pelayo

    2015-01-01

    The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2-3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L ∞ = 110 cm TL, and to = - 1.7 years) show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female) was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F), with a large majority of the individuals in our experimental catch being immature (79%). Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability.

  2. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840)

    PubMed Central

    Friedlander, Alan M.; DeMartini, Edward E.; Schuhbauer, Anna; Schemmel, Eva; Salinas de Léon, Pelayo

    2015-01-01

    The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2–3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L∞ = 110 cm TL, and to = − 1.7 years) show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female) was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F), with a large majority of the individuals in our experimental catch being immature (79%). Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability. PMID:26401463

  3. Heterosis, maternal and direct effects in double-muscled and normal cattle: I. Reproduction and growth traits.

    PubMed

    Arthur, P F; Makarechian, M; Price, M A; Berg, R T

    1989-04-01

    Data from a two-breed group diallel experiment involving double-muscled (DM) and normal (N) cattle were analyzed to evaluate the importance of heterosis, maternal and direct effects for reproduction and growth traits. The DM cattle were from a composite of primarily Angus, Charolais, Galloway and Hereford breeds, and N cattle were crossbred cattle with at least 50% Hereford breeding. The data comprised a total of 491 matings and 389 calvings in four breeding seasons. Records on calving performance, calving date, calf crop born and weaned, sex ratio of progeny and weight of calves were analyzed using least squares procedures. Significant heterosis of 5 to 12% was observed for all the calf crop and growth traits, except for birth weight. Heterosis resulted in 24% reduction in the incidence of dystocia and perinatal calf mortality (P less than .05). The significant heterosis was due mainly to poor production in DM X DM crosses. The DM cows were superior (P less than .05) to N cows in reciprocal crossing (maternal effect) for all the calf crop traits, but had higher incidence of calving difficulty and a higher proportion of male progeny. Significant direct effect was observed for all the traits except calving date and sex ratio among progeny. The N sires were superior for all the calf crop traits and caused less incidence of dystocia and perinatal mortality compared with the DM sires. Significant differences were obtained between the straightbreds for all the traits except calving date. The N straightbreds were superior to the DM straightbreds for all the significant traits.

  4. Allometry and development in herbaceous plants: functional responses of meristem allocation to light and nutrient availability.

    PubMed

    Bonser, Stephen P; Aarssen, Lonnie W

    2003-03-01

    We examined the relationship between meristem allocation and plant size for four annual plant species: Arabidopsis thaliana, Arenaria serphyllifolia, Brassica rapa, and Chaenorrhinum minus. Gradients of light and nutrient availability were used to obtain a range of plant sizes for each of these species. Relative allocation to reproductive, inactive, and growth meristems were used to measure reproductive effort, apical dominance, and branching intensity, respectively. We measured allocation to each of these three meristem fates at weekly intervals throughout development and at final developmental stage. At all developmental stages reproductive effort and branching intensity tended to increase with increasing plant size (i.e., due to increasing resource availability) and apical dominance tended to decrease with increasing plant size. We interpret these responses as a strategy for plants to maximize fitness across a range of environments. In addition, significant differences in meristem response among species may be important in defining the range of habitats in which a species can exist and may help explain patterns of species competition and coexistence in habitats with variable resource availability.

  5. Effects of age and reproductive experience on the distribution of prolactin and growth hormone secreting cells in the anterior pituitary of a passerine.

    PubMed

    Christensen, Debora; Vleck, Carol M

    2015-10-01

    Plasma prolactin (PRL) is released from lactotrophs in the anterior pituitary. As plasma PRL levels rise during incubation in domestic fowl, the number of lactotrophs (PRL-immunoreactive, PRL-IR cells) increases while the number of growth hormone secreting cells, somatotrophs (GH-IR cells), declines. We measured plasma PRL levels using radioimmunoassay (RIA) and examined the distribution of lactotrophs and somatotrophs in the anterior pituitary of breeding and nonbreeding zebra finches of known ages with and without prior breeding experience using fluorescent immunohistochemistry (IHC). Plasma PRL levels were higher in breeding than in nonbreeding birds, regardless of age, sex, or previous breeding history. PRL-IR cells were localized primarily, but not exclusively, to the cephalic aspect of the anterior pituitary (AP) and along the ventral margin. Birds with prior reproductive experience had more PRL-IR cells than birds with no prior reproductive experience and breeders had slightly higher PRL-IR cell counts than did nonbreeders, but there was no correlation between the number of PRL-IR cells and plasma PRL levels. GH-IR cells were concentrated in the caudal aspect of the AP with some cells in the cephalic lobe, but numbers did not differ between any of the groups studied. An increase in PRL-IR cells corresponded with an increase in GH-IR cells. An increase in lactotroph number with reproductive experience in zebra finches may facilitate future reproductive events by allowing for more robust PRL secretion and increased reproductive success.

  6. Growth characteristics, reproductive performance, and evaluation of their associative relationships in Brangus cattle managed in a Chihuahuan Desert production system1.

    PubMed

    Luna-Nevarez, P; Bailey, D W; Bailey, C C; VanLeeuwen, D M; Enns, R M; Silver, G A; DeAtley, K L; Thomas, M G

    2010-05-01

    Balancing growth and reproductive performance in beef cattle managed in desert environments is challenging. Our objectives were to 1) evaluate trends in growth and reproductive traits, and 2) assess associative relationships between growth characteristics and reproductive performance in a Brangus herd managed in a Chihuahuan Desert production system from 1972 to 2006. Data were from bull (n = 597) and heifer calves (n = 585; 1988 to 2006) and cows (n = 525; repeated records of cows, n = 2,611; 1972 to 2006). Variables describing the growth curve of each cow were estimated using a nonlinear logistic function (each cow needed 6 yr of data). Mixed-effect models and logistic regression were used to analyze trends across years in growth and reproductive traits (both continuous and categorical). For continuous traits of calves, a slight cubic response (P < 0.01) described the dynamics of birth weight, 205-d BW, and 365-d BW across years. For categorical traits of females, positive linear trends (P < 0.05) across years were observed in percent pregnant as yearlings, calved at 2 yr of age, and first-calf heifer rebreeding (slopes ranged from 0.007 to 0.014%/yr). Autumn cow BW increased gradually until 1997 (509 kg +/- 8.8) and then decreased gradually by 0.6 kg/yr, whereas pregnancy percentage decreased gradually until 1995 (78.4% +/- 1.0) and then increased slightly by 0.2%/yr. A quadratic effect best described the dynamics of these 2 variables across years (P < 0.01) as well as estimates describing the growth curve of each cow. Specifically, asymptotic BW and age increased (P < 0.05) from 1972 to 1983 and 1990, respectively. Asymptotic age then decreased by 27% from 1983 to 1996 (P < 0.05). The maturing rate index was negatively correlated with age at first calving and calving interval (r = -0.42 and -0.18, P < 0.01), which suggested that early-maturing cows had enhanced fertility in this environment and production system. In summary, minimal changes were observed in

  7. Maternal backfat depth in gestating sows has a greater influence on offspring growth and carcass lean yield than maternal feed allocation during gestation.

    PubMed

    Amdi, Charlotte; Giblin, Linda; Ryan, Tomas; Stickland, Neil C; Lawlor, Peadar G

    2014-02-01

    A commercial pig spends nearly half of its life in utero and its nutrition during this time can influence birth weight and postnatal growth. We hypothesised that postnatal growth is increased in pigs raised by sows with a high backfat depth and high level of energy intake during gestation compared with sows with a low backfat depth and low level of energy intake during gestation. This was tested in a 2 × 3 factorial design experiment with 2 factors for gilt backfat depth (Thin and Fat) and 3 factors for gestation feed allowance (Restricted, Control and High). Between d 25 and d 90 of gestation, Thin gilts (n=68; 12 ± 0.6 mm P2 backfat) and Fat gilts (n=72; 19 ± 0.6 mm P2 backfat) were randomly allocated, as individuals, to a gestation diet (6.19 g/kg lysine, 13.0 MJ DE/kg) at the following feed allowances: 1.8 kg/day (Restricted); 2.5 kg/day (Control) and 3.5 kg/day (High). For the remainder of gestation and during lactation all gilts were treated similarly. At weaning (day 28), 155 piglets were sacrificed and 272 were individually housed and followed through to slaughter (day 158). At day 80 of gestation, fasted Thin Restricted gilts had lower serum IGF-1 concentrations than Thin High or Thin Control fed gilts (P<0.001). Pigs born from Fat gilts had greater backfat depths (P<0.05), a lower lean meat yield (P<0.05) and were heavier (P<0.05) at slaughter than pigs born from Thin gilts. Gilt gestation feed allowance had only transitory effects on average daily gain and feed conversion efficiency and had no effect on pig weight at slaughter (P>0.05) or lean meat yield (P>0.05). In conclusion, gilts with a backfat depth of ~19 mm at insemination produced pigs that were heavier and fatter at ~158 days of age than those born from gilts with ~12 mm backfat depth at insemination. Maternal body condition during gestation had a more predominant influence on growth parameters of the offspring, such as weight at slaughter and backfat depth, than did feed level during

  8. Effects of development mode, contaminated sediments, and maternal characteristics on growth and reproduction in the polychaetes Streblospio benedicti (Spionidae) and Capitella sp. I (Capitellidae)

    SciTech Connect

    Bridges, T.S.

    1992-01-01

    Experiments were conducted to examine the effects of contaminated sediments (sewage, blue-green algae and hydrocarbons) and maternal characteristics on reproduction, and offspring success in S. benedicti (lecithotrophic) and Capitella sp. I. For S. benedicti, contaminated sediments had a negative effect on growth and age and size at first reproduction. Per brood fecundity was positively related to female size and negatively related to female age. Treatments did not have an effect on reproductive output. Per offspring C and N investment increased with female age. This increase in per offspring investment resulted in enhanced survivorship and juvenile growth in offspring of older females. For Capitella sp. I, growth was increased, age at first reproduction was accelerated, and per brood fecundity was 3--4 [times] higher in the algae and sewage treatments. Treatments did not have an effect on reproductive output. Fecundity was positively related to female size. Per brood and per offspring C and N investment decreased with female age, but not in all treatments. The C:N ratio of offspring increased with female age. Offspring from mothers in the sewage treatment were larger two weeks after release. Offspring in size two weeks after release decreased with female age in the sewage treatment. Differences in the response of S. benedicti and Capitella sp. I to contaminated sediments may be due to differences in feeding behavior, digestive physiology, nutritional requirements and their sensitivity to hydrocarbons, metals and low oxygen concentrations. Differences in the effect of female age between the two species appear related to development and ecological differences in the two species.

  9. Influence of host plant on growth and reproduction of Aphis nerii and feeding and prey utilization of its predator Menochilus sexmaculatus.

    PubMed

    Murugan, K; Jeyabalan, D; Kumar, N S; Nathan, S S; Sivaramakrishnan, S

    2000-06-01

    Influence of different physiological stages (young, mature and senescent) of Calotropis gigantea leaves on growth and reproductive ability of A. nerii and feeding, prey utilization, fecundity and lipid content of its predator M. sexmaculatus were investigated. Increased reproductive period, total life span and reproduction of nymphs per female of A. nerii were observed when reared on mature leaves. This relative preference of A. nerii and maximum utilization of mature leaves as compared to other physiological aged leaves are mainly due to changes in the chemical composition such as protein, carbohydrate, lipid, amino acid, nitrogen and phenolic of C. gigantea. Further, aphids reared on mature leaves influenced its predator's (M. sexmaculatus) growth, prey utilization and reproductive performances. Fecundity and longevity were high, while developmental time of predator was shorter on mature leaves fed aphid. Maximum prey utilization and increased efficiency of ingested and digested food of predator was observed on mature leaves reared aphid. The results are interpreted and discussed in relation to plant aphid and predator interaction (tritrophic).

  10. Breeding and Housing Laboratory Rats and Mice in the Same Room Does Not Affect the Growth or Reproduction of Either Species

    PubMed Central

    Pritchett-Corning, Kathleen R; Chang, Fon T; Festing, Michael F W

    2009-01-01

    Few data exist regarding the effects of long-term housing of rats and mice in the same secondary enclosure. Historical reproductive and growth data were compared for colonies of mice and rats maintained in open-topped cages in either single-species or dual-species barrier rooms. This analysis included reproductive parameters (litter size at birth, litter size at weaning, and pups missing at weaning) collected from 33 colonies of mice comprising 500 to 38,500 breeding females and 28 colonies of rats totaling 350 to 4,600 breeding females, and representative samples from 28 colonies of each species were analyzed for weight gain from weaning to adulthood. The presence or absence of the other species was not associated with statistically significant differences in weight gain or any of the reproductive parameters. These results suggest that breeding colonies of rats and mice of the same health status can be housed in the same room without a negative effect on the growth and reproduction of either species. PMID:19807969

  11. Ovarian follicular development and the follicular fluid hormones and growth factors in normal women of advanced reproductive age.

    PubMed

    Klein, N A; Battaglia, D E; Miller, P B; Branigan, E F; Giudice, L C; Soules, M R

    1996-05-01

    Reproductive aging in women (a physiological decline in the function of the hypothalamic-pituitary-ovarian axis) is an infrequently investigated and poorly understood biological phenomenon. Although menstrual irregularity and anovulation are known to precede the menopause, normal women in their fifth decade experience a profound decrease in fertility while still experiencing regular menstrual cycles. To further our understanding of the physiological changes associated with reproductive aging, this study examined the spontaneous development and function of ovarian follicles in normal women, aged 40-45 yr. The subjects were women (n = 21), aged 40-45 yr, who had regular 25- to 35-day ovulatory menstrual cycles, were not infertile, had no medical problems, and met specific criteria for weight, diet, and exercise. The controls were normal women (n = 20), age 20-25 yr, who met the same criteria. The subjects were monitored with daily hormone measurements [LH, FSH, estradiol (E), progesterone (P), and inhibin] and pelvic sonograms from day 1 of their study cycle until the dominant ovarian follicle reached a mean diameter of 15 mm and/or a serum E level of 550 pmol/L or higher was attained. At that time, 10,000 U hCG were given, and a transvaginal sonographic follicle aspiration was performed 32 h later. The follicular fluid (FF) was collected, stored frozen at -70 C, and later analyzed for E, P, testosterone (T), androstenedione, inhibin, insulin-like growth factor I (IGF-I), and IGF-II. The number of cycle days to aspiration was lower (11.6 vs. 15.6 days; P < 0.001) and the early follicular phase mean FSH and mean E levels were higher (9.3 vs. 6.6 mIU/mL and 305 vs. 160 pmol/L; P < 0.01) in the older (O) group compared to the younger group. There was a strong trend toward higher FF mean E (2280 vs. 1931 nmol/L) and lower FF mean T (978 vs. 2361 pmol/L) levels in group O. The E/T ratio was significantly higher (5253 vs. 2408; P < 0.03) in group O. In group O, the mean FF

  12. Ovarian follicular development and the follicular fluid hormones and growth factors in normal women of advanced reproductive age.

    PubMed

    Klein, N A; Battaglia, D E; Miller, P B; Branigan, E F; Giudice, L C; Soules, M R

    1996-05-01

    Reproductive aging in women (a physiological decline in the function of the hypothalamic-pituitary-ovarian axis) is an infrequently investigated and poorly understood biological phenomenon. Although menstrual irregularity and anovulation are known to precede the menopause, normal women in their fifth decade experience a profound decrease in fertility while still experiencing regular menstrual cycles. To further our understanding of the physiological changes associated with reproductive aging, this study examined the spontaneous development and function of ovarian follicles in normal women, aged 40-45 yr. The subjects were women (n = 21), aged 40-45 yr, who had regular 25- to 35-day ovulatory menstrual cycles, were not infertile, had no medical problems, and met specific criteria for weight, diet, and exercise. The controls were normal women (n = 20), age 20-25 yr, who met the same criteria. The subjects were monitored with daily hormone measurements [LH, FSH, estradiol (E), progesterone (P), and inhibin] and pelvic sonograms from day 1 of their study cycle until the dominant ovarian follicle reached a mean diameter of 15 mm and/or a serum E level of 550 pmol/L or higher was attained. At that time, 10,000 U hCG were given, and a transvaginal sonographic follicle aspiration was performed 32 h later. The follicular fluid (FF) was collected, stored frozen at -70 C, and later analyzed for E, P, testosterone (T), androstenedione, inhibin, insulin-like growth factor I (IGF-I), and IGF-II. The number of cycle days to aspiration was lower (11.6 vs. 15.6 days; P < 0.001) and the early follicular phase mean FSH and mean E levels were higher (9.3 vs. 6.6 mIU/mL and 305 vs. 160 pmol/L; P < 0.01) in the older (O) group compared to the younger group. There was a strong trend toward higher FF mean E (2280 vs. 1931 nmol/L) and lower FF mean T (978 vs. 2361 pmol/L) levels in group O. The E/T ratio was significantly higher (5253 vs. 2408; P < 0.03) in group O. In group O, the mean FF

  13. Female reproduction and pup survival and growth for mice fed a cadmium-containing purified diet through six consecutive rounds of gestation and lactation

    SciTech Connect

    Whelton, B.D.; Bhattacharyya, M.H.; Carnes, B.A.; Moretti, E.S.; Peterson, D.P.

    1988-01-01

    Female CF1 mice were bred for 6 consecutive, 42-d rounds of gestation-lactation. Their purified diets contained cadmium added at either 0.25, 5.0, or 50.0 ppm Cd; at each cadmium level, the diets were either sufficient or deficient in certain vitamins, minerals, and fat. The deficient diet at 5 ppm cadmium was designed to simulate conditions implicated in the etiology of itai-itai disease among multiparous women in Japan, Fertility, litter size, pup survival, and pup growth (weaning weight) are reported for mice on the six diets during each of the six rounds of gestation/lactation. Except for fertility, decreases in reproductive measures that occurred in response to dietary deficiencies of cadmium during round 1 or reproduction were repeated, unchanged in magnitude, in each successive round. For sufficient diet groups, 50 ppm cadmium had no effect on fertility or pup survival during lactation, but caused a 15% decrease in litter size at birth and a 25% decrease in pup growth. Dietary deficiencies alone decreased all four measures of reproductive performance; fertility by 12%, litter size by 30%, pup survival by 18%, and pup growth by 42%. In addition, dietary deficiencies strikingly decreased the incidence of consecutive pregnancies. Combined effects of 50 ppm cadmium and dietary deficiencies were additive for all reproductive measures except fertility; for fertility, cadmium caused no decrease in the fertility of sufficient-diet animals, but caused a striking 45% decrease in deficient-diet animals. Relating the authors results to humans, women who contracted the itai-itai disease (analogous to mice on the deficient, 5 ppm cadmium diet), in addition to their characteristic bone disease, could have experienced decreases in fertility and in growth of their offspring related to their dietary deficiencies.

  14. Do tiny males grow up? Sperm competition and optimal resource allocation schedule of dwarf males of barnacles.

    PubMed

    Yamaguchi, Sachi; Ozaki, Yuki; Yusa, Yoichi; Takahashi, Satoshi

    2007-03-21

    Barnacles, marine crustaceans, have three sexual patterns: simultaneous hermaphroditism, dioecy and androdioecy. In dioecy and androdioecy, large individuals (females and hermaphrodites, respectively) are attached by dwarf males. Depending on species, some dwarf males grow up, others do not in their life time. To investigate which environmental conditions affect growth patterns of dwarf males of barnacles, we investigate the evolutionarily stable life history strategy of dwarf males using Pontryagin's maximum principle. Sperm competition among dwarf males and that among dwarf males and large hermaphrodites is taken into account. Dwarf males grow up in food-rich environments, while they do not grow at all in food-poor environments. ESS of the resource allocation schedule between reproduction and growth follows an "intermediate growth strategy" (simultaneous growth and reproduction) for dioecious species, in which sperm competition is not severe. On the other hand, it approaches "bang-bang control" (switching from allocating all resources toward growth then to reproduction), as sperm competition against surrounding large hermaphrodites becomes severe in androdioecious species.

  15. Characterization of Growth and Reproduction Performance, Transgene Integration, Expression, and Transmission Patterns in Transgenic Pigs Produced by piggyBac Transposition-Mediated Gene Transfer.

    PubMed

    Zeng, Fang; Li, Zicong; Cai, Gengyuan; Gao, Wenchao; Jiang, Gelong; Liu, Dewu; Urschitz, Johann; Moisyadi, Stefan; Wu, Zhenfang

    2016-10-01

    Previously we successfully produced a group of EGFP-expressing founder transgenic pigs by a newly developed efficient and simple pig transgenesis method based on cytoplasmic injection of piggyBac plasmids. In this study, we investigated the growth and reproduction performance and characterized the transgene insertion, transmission, and expression patterns in transgenic pigs generated by piggyBac transposition. Results showed that transgene has no injurious effect on the growth and reproduction of transgenic pigs. Multiple copies of monogenic EGFP transgene were inserted at noncoding sequences of host genome, and passed from founder transgenic pigs to their transgenic offspring in segregation or linkage manner. The EGFP transgene was ubiquitously expressed in transgenic pigs, and its expression intensity was associated with transgene copy number but not related to its promoter DNA methylation level. To the best of our knowledge, this is first study that fully described the growth and reproduction performance, transgene insertion, expression, and transmission profiles in transgenic pigs produced by piggyBac system. It not only demonstrates that piggyBac transposition-mediated gene transfer is an effective and favorable approach for pig transgenesis, but also provides scientific information for understanding the transgene insertion, expression and transmission patterns in transgenic animals produced by piggyBac transposition. PMID:27565868

  16. Age-related variation in carbon allocation at tree and stand scales in beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.) using a chronosequence approach.

    PubMed

    Genet, H; Bréda, N; Dufrêne, E

    2010-02-01

    Two types of physiological mechanisms can contribute to growth decline with age: (i) the mechanisms leading to the reduction of carbon assimilation (input) and (ii) those leading to modification of the resource economy. Surprisingly, the processes relating to carbon allocation have been little investigated as compared to research on the processes governing carbon assimilation. The objective of this paper was thus to test the hypothesis that growth decrease related to age is accompanied by changes in carbon allocation to the benefit of storage and reproductive functions in two contrasting broad-leaved species: beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Age-related changes in carbon allocation were studied using a chronosequence approach. Chronosequences, each consisting of several even-aged stands ranging from 14 to 175 years old for beech and from 30 to 134 years old for sessile oak, were divided into five or six age classes. In this study, carbon allocations to growth, storage and reproduction were defined as the relative amount of carbon invested in biomass increment, carbohydrate increment and seed production, respectively. Tree-ring width and allometric relationships were used to assess biomass increment at the tree and stand scales. Below-ground biomass was assessed using a specific allometric relationship between root:shoot ratio and age, established from the literature review. Seasonal variations of carbohydrate concentrations were used to assess carbon allocation to storage. Reproduction effort was quantified for beech stands by collecting seed and cupule production. Age-related flagging of biomass productivity was assessed at the tree and stand scales, and carbohydrate quantities in trees increased with age for both species. Seed and cupule production increased with stand age in beech from 56 gC m(-)(2) year(-1) at 30 years old to 129 gC m(-2) year(-1) at 138 years old. In beech, carbon allocation to storage and

  17. Gonadotropins and Growth Hormone Family Characterization in an Endangered Siluriform Species, Steindachneridion parahybae (Pimelodidae): Relationship With Annual Reproductive Cycle and Induced Spawning in Captivity.

    PubMed

    Honji, Renato Massaaki; Caneppele, Danilo; Pandolfi, Matias; Nostro, Fabiana Laura Lo; Moreira, Renata Guimarães

    2015-09-01

    The aim of this study was to identify and characterize pituitary cells of Steindachneridion parahybae females in captivity, highlighting the possible relationship with reproductive disorders at this level, since this species shows oocyte final maturation, ovulation and spawning dysfunction in captivity. The localization and distribution of growth hormone (GH), prolactin (PRL), somatolactin (SL), β-luteinizing hormone (β-LH), and β-follicle stimulating hormone (β-FSH) immunoreactive (-ir) cells in the adenohypophysis was studied by immunohistochemical and Western blot methods. In addition, cellular morphometric analyses and semi-quantification of ir-cells optical density (OD) during the annual reproductive cycle and after artificial induced spawning (AIS) were performed. Results showed that the distribution and general localization of pituitary cell types were similar to that of other teleost species. However, the morphometrical study of adenohypophysial cells showed differences along the reproductive cycle and following AIS. In general, females at the vitellogenic stage presented greater OD values for GH, PRL and SL than at other maturation stages (previtellogenic and regression stages), probably indicating an increased cellular activity during this stage. Conversely, β-LH OD did not vary during the annual reproductive cycle. After AIS, β-LH, SL and GH ir-cells showed an increase in OD values suggesting a possible involvement on oocyte final maturation, ovulation and spawning or a feedback control on the brain-pituitary-gonads axis. Reproductive dysfunction in S. parahybae females in captivity may be due to alteration of the synthesis pathways of β-LH. In addition, GH family of hormones could modulate associated mechanisms that influence the reproductive status in this species.

  18. Influence of depth on sex-specific energy allocation patterns in a tropical reef fish

    NASA Astrophysics Data System (ADS)

    Hoey, J.; McCormick, M. I.; Hoey, A. S.

    2007-09-01

    The effect of depth on the distribution and sex-specific energy allocation patterns of a common coral reef fish, Chrysiptera rollandi (Pomacentridae), was investigated using depth-stratified collections over a broad depth range (5-39 m) and a translocation experiment. C. rollandi consistently selected rubble habitats at each depth, however abundance patterns did not reflect the availability of the preferred microhabitat suggesting a preference for depth as well as microhabitat. Reproductive investment (gonado-somatic index), energy stores (liver cell density and hepatocyte vacuolation), and overall body condition (hepato-somatic index and Fulton’s K) of female fish varied significantly among depths and among the three reefs sampled. Male conspecifics displayed no variation between depth or reef. Depth influenced growth dynamics, with faster initial growth rates and smaller mean asymptotic lengths with decreasing depth. In female fish, relative gonad weight and overall body condition (Fulton’s K and hepato-somatic index) were generally higher in shallower depths (≤10 m). Hepatic lipid storage was highest at the deepest sites sampled on each reef, whereas hepatic glycogen stores tended to decrease with depth. Depth was found to influence energy allocation dynamics in C. rollandi. While it is unclear what processes directly influenced the depth-related patterns in energy allocation, this study shows that individuals across a broad depth gradient are not all in the same physiological state and may contribute differentially to the population reproductive output.

  19. Effects of generalist herbivory on resistance and resource allocation by the invasive plant, Phytolacca americana.

    PubMed

    Huang, Wei; Ding, Jianqing

    2016-04-01

    Successful invasions by exotic plants are often attributed to a loss of co-evolved specialists and a re-allocation of resources from defense to growth and reproduction. However, invasive plants are rarely completely released from insect herbivory because they are frequently attacked by generalists in their introduced ranges. The novel generalist community may also affect the invasive plant's defensive strategies and resource allocation. Here, we tested this hypothesis using American pokeweed (Phytolacca americana L.), a species that has become invasive in China, which is native to North America. We examined resistance, tolerance, growth and reproduction of plant populations from both China and the USA when plants were exposed to natural generalist herbivores in China. We found that leaf damage was greater for invasive populations than for native populations, indicating that plants from invasive ranges had lower resistance to herbivory than those from native ranges. A regression of the percentage of leaf damage against mass showed that there was no significant difference in tolerance between invasive and native populations, even though the shoot, root, fruit and total mass were larger for invasive populations than for native populations. These results suggest that generalist herbivores are important drivers mediating the defensive strategies and resource allocation of the invasive American pokeweed.

  20. Enough is enough: the effects of symbiotic ant abundance on herbivory, growth, and reproduction in an African acacia.

    PubMed

    Palmer, Todd M; Brody, Alison K

    2013-03-01

    Understanding how cooperative interactions evolve and persist remains a central challenge in biology. Many mutualisms are thought to be maintained by "partner fidelity feedback," in which each partner bases their investment on the benefits they receive. Yet, we know little about how benefits change as mutualists vary their investment, which is critical to understanding the balance between mutualism and antagonism in any given partnership. Using an obligate ant-plant mutualism, we manipulated the density of symbiotic acacia ants (Crematogaster mimosae) and examined how the costs and benefits to Acacia drepanolobium trees scaled with ant abundance. Benefits of ants to plants saturated with increasing ant abundance for protection from branch browsing by elephants and attack by branch galling midges, while varying linearly for protection from cerambycid beetles. In addition, the risk of catastrophic whole-tree herbivory by elephants was highest for trees with very low ant abundance. However, there was no relationship between ant abundance and herbivory by leaf-feeding invertebrates, nor by vertebrate browsers such as giraffe, steinbuck, and Grant's gazelle. Ant abundance did not significantly influence rates of branch growth on acacias, but there was a significant negative relationship between ant abundance and the number of fruits produced by host plants, suggesting that maintaining high-density ant colonies is costly. Because benefits to plants largely saturated with increasing colony size, while costs to plant reproduction increased, we suggest that ant colonies may achieve abundances that are higher than optimal for host plants. Our results highlight the conflicts of interest inherent in many mutualisms, and demonstrate the value of examining the shape of curves relating costs and benefits within these globally important interactions.

  1. Transcriptome Analysis of the Trachinotus ovatus: Identification of Reproduction, Growth and Immune-Related Genes and Microsatellite Markers

    PubMed Central

    Chao, Fang; Qiongyu, Liu; Zihao, Li; Xiaochun, Liu; Yong, Zhang; Shuisheng, Li; Haoran, Lin

    2014-01-01

    Background The Trachinotus ovatus (Teleostei, Carangidae) is an economically important marine fish species in the world. However, the lack of genomic information regarding this species limits our understanding of the genetics and biological mechanisms in Trachinotus ovatus. In this study, high throughput transcriptome sequencing was used to obtain comprehensive genomic information in Trachinotus ovatus. Principal Findings Transcriptome sequencing was performed by using Illumina paired-end sequencing technology. The 98,534,862 high quality reads were yielded, and were de novo assembled into 156,094 unigenes with an average sequence length of 1179 bp. Transcriptome annotation revealed that 75,586 and 67,923 unigenes were functionally annotated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 67,923 unigenes were grouped into 25 Cluster of Orthologous Groups (COG) functional categories, 37,976 unigenes were clustered into 61 Gene Ontology (GO) terms, and 38,172 unigenes were assigned to 275 different Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Based on the transcriptome dataset, a large number of unigenes associated with reproduction, growth and immunity were identified. Furthermore, a total number of 38,794 simple sequence repeats (SSRs) were discovered and 16 polymorphic loci were characterized in Trachinotus ovatus. Conclusion/Significance The present study is the first transcriptome analysis of a fish species belonging to the genus Trachinotus and provides a valuable genomic resource for novel gene discovery, gene expression and regulation studies, and the identification of genetic markers in Trachinotus ovatus and the other fish of the genus Trachinotus. PMID:25303650

  2. Enough is enough: the effects of symbiotic ant abundance on herbivory, growth, and reproduction in an African acacia.

    PubMed

    Palmer, Todd M; Brody, Alison K

    2013-03-01

    Understanding how cooperative interactions evolve and persist remains a central challenge in biology. Many mutualisms are thought to be maintained by "partner fidelity feedback," in which each partner bases their investment on the benefits they receive. Yet, we know little about how benefits change as mutualists vary their investment, which is critical to understanding the balance between mutualism and antagonism in any given partnership. Using an obligate ant-plant mutualism, we manipulated the density of symbiotic acacia ants (Crematogaster mimosae) and examined how the costs and benefits to Acacia drepanolobium trees scaled with ant abundance. Benefits of ants to plants saturated with increasing ant abundance for protection from branch browsing by elephants and attack by branch galling midges, while varying linearly for protection from cerambycid beetles. In addition, the risk of catastrophic whole-tree herbivory by elephants was highest for trees with very low ant abundance. However, there was no relationship between ant abundance and herbivory by leaf-feeding invertebrates, nor by vertebrate browsers such as giraffe, steinbuck, and Grant's gazelle. Ant abundance did not significantly influence rates of branch growth on acacias, but there was a significant negative relationship between ant abundance and the number of fruits produced by host plants, suggesting that maintaining high-density ant colonies is costly. Because benefits to plants largely saturated with increasing colony size, while costs to plant reproduction increased, we suggest that ant colonies may achieve abundances that are higher than optimal for host plants. Our results highlight the conflicts of interest inherent in many mutualisms, and demonstrate the value of examining the shape of curves relating costs and benefits within these globally important interactions. PMID:23687894

  3. Soil water content and patterns of allocation to below- and above-ground biomass in the sexes of the subdioecious plant Honckenya peploides

    PubMed Central

    Sánchez-Vilas, Julia; Bermúdez, Raimundo; Retuerto, Rubén

    2012-01-01

    Background and aims Dioecious plants often show sex-specific differences in growth and biomass allocation. These differences have been explained as a consequence of the different reproductive functions performed by the sexes. Empirical evidence strongly supports a greater reproductive investment in females. Sex differences in allocation may determine the performance of each sex in different habitats and therefore might explain the spatial segregation of the sexes described in many dimorphic plants. Here, an investigation was made of the sexual dimorphism in seasonal patterns of biomass allocation in the subdioecious perennial herb Honckenya peploides, a species that grows in embryo dunes (i.e. the youngest coastal dune formation) and displays spatial segregation of the sexes at the studied site. The water content in the soil of the male- and female-plant habitats at different times throughout the season was also examined. Methods The seasonal patterns of soil-water availability and biomass allocation were compared in two consecutive years in male and female H. peploides plants by collecting soil and plant samples in natural populations. Vertical profiles of below-ground biomass and water content were studied by sampling soil in male- and female-plant habitats at different soil depths. Key Results The sexes of H. peploides differed in their seasonal patterns of biomass allocation to reproduction. Males invested twice as much in reproduction than females early in the season, but sexual differences became reversed as the season progressed. No differences were found in above-ground biomass between the sexes, but the allocation of biomass to below-ground structures varied differently in depth for males and females, with females usually having greater below-ground biomass than males. In addition, male and female plants of H. peploides had different water-content profiles in the soil where they were growing and, when differences existed (usually in the upper layers of the

  4. Age, Growth and Reproduction of the Eastern Mudminnow (Umbra pygmaea) at the Great Swamp National Wildlife Refuge, New Jersey.

    USGS Publications Warehouse

    Panek, Frank; Weis, Judith S.

    2012-01-01

    Umbra pygmaea DeKay (Eastern Mudminnow) is one of four species of Umbridae in North America. There is little published life-history information on the species within its native range, particularly on age, growth, and reproduction. This study focuses on these aspects of the life history of this fish at the Great Swamp National Wildlife Refuge in Morris County, NJ. A total of 336 fish of seven species was collected from June 1978 through May 1979, with the Eastern Mudminnow comprising 74% of the total. The average annual growth increment in total length for the Eastern Mudminnow was 15.3 2.06 mm, with age-1 fish averaging 40 mm total length and age-5 fish, the oldest collected, averaging 107 mm total length. The length-weight relationship was log10W = -5.291 + 3.182 log10TL mm for males and log10W = -4.999 + 3.032 log10TL mm for females. We observed no statistically significant sexually dimorphic differences in length-weight relationships in this population. The ratio of females to males increased from a low of 0.6 (predominance of male fish) at age-1 to a high of 4.6 (predominance of females) at age-5. Annual mortality for age 2–5 fish ranged from 40–76% with a mean of 59 13%. Age-specific fecundity estimates ranged from 250 eggs/female at age-1 to 2168 eggs/female at age-5. The relationship of number of mature ova to age was best described by the exponential function y = 149.29e0.5287x, where y = age-specific fecundity and x = age in years. Ova ranged from 0.1–0.2 mm in diameter in June and July and averaged 1.41 0.1 mm (range = 1.29–1.62 mm) in early February prior to spawning. Peak spawning occurred in mid-April at temperatures of 9–12 °C, and all females were spent by late April (13–15 °C).

  5. Comparison of diet, reproductive biology, and growth of the pig frog (Rana grylio) from harvested and protected areas of the Florida Everglades

    USGS Publications Warehouse

    Ugarte, C.A.; Rice, K.G.; Donnelly, M.A.

    2007-01-01

    Distinct differences in body size exist among three Rana grylio populations in areas of the Florida Everglades that differ in frog harvest pressure and hydroperiod. Frogs from two populations are harvested regularly throughout the year, while those in the third are protected from harvest. We compared seasonal and sex differences in diet, reproduction, and growth across these populations to examine life-history patterns. By volume, crayfish and anurans were the most abundant prey items for all adults across sites. Frogs from drier sites consumed more crayfish than frogs from the wettest site. Anurans were abundant in the diet during the wet season, while crayfish and fish were abundant during the dry season. More frogs with empty stomachs were captured during the wet season than the dry season. Feeding, growth, and fat deposition were greatest during the dry season across all sites. Although females were found in all reproductive stages throughout the year, the highest percentage of females had mature ova during the late dry season and spent ovaries during the early wet season. Individual patterns of growth were similar across all sites and matched historical growth data from the 1950s. Differences in body size among sites were most likely attributable to differential mortality (i.e., harvest pressure, predation) rather than to differences in food access or growth. ?? 2007 by the American Society of Ichthyologists and Herpetologists.

  6. Additive and non-additive effects of simulated leaf and inflorescence damage on survival, growth and reproduction of the perennial herb Arabidopsis lyrata.

    PubMed

    Puentes, Adriana; Ågren, Jon

    2012-08-01

    Herbivores may damage both leaves and reproductive structures, and although such combined damage may affect plant fitness non-additively, this has received little attention. We conducted a 2-year field experiment with a factorial design to examine the effects of simulated leaf (0, 12.5, 25, or 50% of leaf area removed) and inflorescence damage (0 vs. 50% of inflorescences removed) on survival, growth and reproduction in the perennial herb Arabidopsis lyrata. Leaf and inflorescence damage negatively and independently reduced flower, fruit and seed production in the year of damage; leaf damage also reduced rosette size by the end of the first season and flower production in the second year. Leaf damage alone reduced the proportion of flowers forming a fruit and fruit production per plant the second year, but when combined with inflorescence damage no such effect was observed (significant leaf × inflorescence damage interaction). Damage to leaves (sources) caused a greater reduction in future reproduction than did simultaneous damage to leaves and inflorescences (sinks). This demonstrates that a full understanding of the effects of herbivore damage on plant fitness requires that consequences of damage to vegetative and reproductive structures are evaluated over more than 1 year and that non-additive effects are considered.

  7. Additive and non-additive effects of simulated leaf and inflorescence damage on survival, growth and reproduction of the perennial herb Arabidopsis lyrata.

    PubMed

    Puentes, Adriana; Ågren, Jon

    2012-08-01

    Herbivores may damage both leaves and reproductive structures, and although such combined damage may affect plant fitness non-additively, this has received little attention. We conducted a 2-year field experiment with a factorial design to examine the effects of simulated leaf (0, 12.5, 25, or 50% of leaf area removed) and inflorescence damage (0 vs. 50% of inflorescences removed) on survival, growth and reproduction in the perennial herb Arabidopsis lyrata. Leaf and inflorescence damage negatively and independently reduced flower, fruit and seed production in the year of damage; leaf damage also reduced rosette size by the end of the first season and flower production in the second year. Leaf damage alone reduced the proportion of flowers forming a fruit and fruit production per plant the second year, but when combined with inflorescence damage no such effect was observed (significant leaf × inflorescence damage interaction). Damage to leaves (sources) caused a greater reduction in future reproduction than did simultaneous damage to leaves and inflorescences (sinks). This demonstrates that a full understanding of the effects of herbivore damage on plant fitness requires that consequences of damage to vegetative and reproductive structures are evaluated over more than 1 year and that non-additive effects are considered. PMID:22349755

  8. Reproductive strategies in snakes.

    PubMed Central

    Shine, Richard

    2003-01-01

    Snakes of both sexes display remarkable flexibility and diversity in their reproductive tactics. Many features of reproduction in female snakes (such as reproductive mode and frequency, seasonality and multiple mating) allow flexible maternal control. For example, females can manipulate not only the genotypes of their offspring (through mate choice or enhanced sperm competition) but also the phenotypes of their offspring (through allocation 'decisions', behavioural and physiological thermoregulation, and nest-site selection). Reliance on stored energy ('capital') to fuel breeding results in low frequencies of female reproduction and, in extreme cases, semelparity. A sophisticated vomeronasal system not only allows male snakes to locate reproductive females by following scent trails, but also facilitates pheromonally mediated mate choice by males. Male-male rivalry takes diverse forms, including female mimicry and mate guarding; combat bouts impose strong selection for large body size in males of s