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Sample records for physiology plant

  1. Polyamines in plant physiology

    NASA Technical Reports Server (NTRS)

    Galston, A. W.; Sawhney, R. K.

    1990-01-01

    The diamine putrescine, the triamine spermidine, and the tetramine spermine are ubiquitous in plant cells, while other polyamines are of more limited occurrence. Their chemistry and pathways of biosynthesis and metabolism are well characterized. They occur in the free form as cations, but are often conjugated to small molecules like phenolic acids and also to various macromolecules. Their titer varies from approximately micromolar to more than millimolar, and depends greatly on environmental conditions, especially stress. In cereals, the activity of one of the major polyamine biosynthetic enzymes, arginine decarboxylase, is rapidly and dramatically increased by almost every studied external stress, leading to 50-fold or greater increases in putrescine titer within a few hours. The physiological significance of this increase is not yet clear, although most recent work suggests an adaptive, protective role. Polyamines produced through the action of ornithine decarboxylase, by contrast, seem essential for DNA replication and cell division. The application of exogenous polyamines produces effects on patterns of senescence and morphogenesis, suggesting but not proving a regulatory role for polyamines in these processes. The evidence for such a regulatory role is growing.

  2. Plant Physiological Aspects of Silicon

    SciTech Connect

    Epstein, E.; Fan, T.W-M.; Higashi, R.M.; Silk, W.K.

    2002-07-10

    The element silicon, Si, represents an anomaly in plant physiology (Epstein, 1994, 1999b). Plants contain the element in amounts comparable to those of such macronutrient elements as phosphorus, calcium, magnesium, viz. at tissue concentrations (dry weight basis) of about 0.1-10%, although both lower and higher values may be encountered. In some plants, such as rice and sugarcane, Si may be the mineral element present in largest amount. In much of plant physiological research, however, Si is considered a nonentity. Thus, not a single formulation of the widely used nutrient solutions includes Si. Experimental plants grown in these solutions are therefore abnormally low in their content of the element, being able to obtain only what Si is present as an unavoidable contaminant of the nutrient salts used, and from the experimental environment and their own seeds. The reason for the astonishing discrepancy between the prominence of Si in plants and its neglect in much of the enterprise of plant physiological research is that Si does not qualify as an ''essential'' element. Ever since the introduction of the solution culture method in the middle of the last century (Epstein, 1999a, b) it has been found that higher plants can grow in nutrient solutions in the formulation of which Si is not included. The only exceptions are the Equisitaceae (horsetails or scouring rushes), for which Si is a quantitatively major essential element.

  3. Some Recent Advances in Plant Physiology

    ERIC Educational Resources Information Center

    Stafford, G. A.

    1972-01-01

    A popular review of plant physiological research, emphasizing those apsects of plant metabolism where there has been a recent shift in emphasis that is not yet reflected in secondary school advanced texts. (AL)

  4. Plant physiology for profitable pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A basic question of pasture-based livestock production is whether producers should manage pastures on the basis of what is best for the animal or what is best for the plant. Given that pastures are the principal and most economical source of feed, producers should carefully consider how they manage...

  5. Evolutionary plant physiology: Charles Darwin's forgotten synthesis

    NASA Astrophysics Data System (ADS)

    Kutschera, Ulrich; Niklas, Karl J.

    2009-11-01

    Charles Darwin dedicated more than 20 years of his life to a variety of investigations on higher plants (angiosperms). It has been implicitly assumed that these studies in the fields of descriptive botany and experimental plant physiology were carried out to corroborate his principle of descent with modification. However, Darwin’s son Francis, who was a professional plant biologist, pointed out that the interests of his father were both of a physiological and an evolutionary nature. In this article, we describe Darwin’s work on the physiology of higher plants from a modern perspective, with reference to the following topics: circumnutations, tropisms and the endogenous oscillator model; the evolutionary patterns of auxin action; the root-brain hypothesis; phloem structure and photosynthesis research; endosymbioses and growth-promoting bacteria; photomorphogenesis and phenotypic plasticity; basal metabolic rate, the Pfeffer-Kleiber relationship and metabolic optimality theory with respect to adaptive evolution; and developmental constraints versus functional equivalence in relationship to directional natural selection. Based on a review of these various fields of inquiry, we deduce the existence of a Darwinian (evolutionary) approach to plant physiology and define this emerging scientific discipline as the experimental study and theoretical analysis of the functions of green, sessile organisms from a phylogenetic perspective.

  6. Elements of plant physiology in theophrastus' botany.

    PubMed

    Pennazio, Sergio

    2014-01-01

    For thousands of years the plants were considered only as a source of food and medicine, and as ornamental objects. Only from the fifth century BC, some philosophers of Ancient Greece realized that the plants were living organisms but, unfortunately, their works have come to us as fragments that we often know from the biological works of Aristotle. This eminent philosopher and man of science, however, did not give us a complete work on the plants, which he often promised to write. From scattered fragments of his conspicuous biological work, it emerges a concept of nutritive soul that, in the presence of heat and moisture, allows plants to grow and reproduce. The task of writing a comprehensive botanical work was delegated to his first pupil, Theophrastus, who left us two treatises over time translated into the various languages up to the current versions (Enquiry into plants, On the causes of plants). The plant life is described and interpreted on the basis of highly accurate observations. The physiological part of his botany is essentially the nutrition: According to Theophrastus, plants get matter and moisture from the soil through root uptake and process the absorbed substances transforming them into food, thanks to the heat. The processing (pepsis, coction) of matter into the food represents an extraordinary physiological intuition because individual organs of a plant appear to perform its specific transformation. Despite that Theophrastus did not do scientific experiments or use special methods other than the sharpness of his observations, he can be considered the forerunner of a plant physiology that would take rebirth only after two millennia.

  7. Physiological conjunction of allelochemicals and desert plants.

    PubMed

    Yosef Friedjung, Avital; Choudhary, Sikander Pal; Dudai, Nativ; Rachmilevitch, Shimon

    2013-01-01

    Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds) were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

  8. The need for plant electro-physiology

    NASA Astrophysics Data System (ADS)

    Gorgolewski, S.

    The already experimentaly evidenced existance of electrotropism for some plant species permits me to propose to extend these studies. Electrotropism is not well defined in plant physiology handbooks. There is a confusion of current and electric field which leads to communication problems between biologists and physicists. The electric field E, is measured in units of volts/metre=newtons/coulomb. We do not attach any wires to the plant leaves but subject them to the electric field. The plant distords the electrical field lines which in turn modify the shape of the plant. It has been verified in fitotron experiments that the direction and strength of the E vector relative to the gravitational force has different effects on plant growth. The natural fair weather global value of E is close to 130 V/m with positive charges in the air and negative on the ground. The most important results are: fields of (1.6 kV/m) enhance plant growth. Reversed fields overwhelm the gravitational field and plants grow towards the grownd. Horizontal E also enhances the plant growth in the horizontal direction ignoring the gravity. It shows that we can restore the directional orientation for plants in the absence of gravity by means of electrotropism. This is an important result for the plant growth in micro-gravity, basic advantage for long duration space fligths for raising edible crops for the vegetarian crew. It has the advantage of selecting in laboratory environment the plants which are suitable for space applications. The use of electic fields in ground based and space plant cultivation opens up important applications based on these novel trends also in modern greenhouses including the Biosphere 2. In addition to the fitotron experiments we have also studied plant growth in natural and modified natural electrical field environment. Two pioneering papers describing the above mentioned results and their possible ground based and space applications are cited as well as several

  9. Plant organ chambers in plant physiology field research

    SciTech Connect

    Sinclair, T.R.

    1980-10-01

    Plant organ chambers used for measuring gas exchange demonstrate that with due-concern for the chamber environment and for the normal growth of the plants, useful data on physiological performance under field conditions can be collected. Recent advances in electronics, particularly the development of minicomputers and microprocessors, have greatly expanded the potential for monitoring and controlling plant organ chambers in field physiology research. These tools allow the scope of the research to be considerably broadened because many chambers can be observed essentially simultaneously and continuously on a long-term basis. The inherent limitations of artificialities and ambiguities in the data can be minimized by good control of the chamber environment and a multiplicity of chambers. While these technological advances allow intensive field physiological research, they also require a substantial commitment from the experimenter. During the data collection, a continuing, long-term effort is required to assure high quality data. Having completed the data collection, the experimenter is confronted with a very large volume of data that must be analyzed and interpreted. Yet, the rewards of these commitments appear to be an ever-increasing understanding of the physiological processes existing in plants grown under field conditions.

  10. Current topics in plant biochemistry and physiology: Volume 6

    SciTech Connect

    Randall, D.D.; Sharp, R.E.; Novacky, A.J.; Blevins, D.G.

    1987-01-01

    These proceedings represent papers presented at the Sixth Annual Plant Biochemistry and Physiology Symposium held at the University of Missouri-Columbia, April 1-3, 1987 and hosted by the Interdisciplinary Plant Biochemistry and Physiology Group. The Interdisciplinary Plant Group was organized to facilitate research and training through interdisciplinary and cooperative approaches to problems facing Plant Biochemistry and Physiology. This annual Symposium is a means of maintaining an awareness of the advances in pertinent research areas.

  11. Comparative physiology of elemental distributions in plants

    PubMed Central

    Conn, Simon; Gilliham, Matthew

    2010-01-01

    Background Plants contain relatively few cell types, each contributing a specialized role in shaping plant function. With respect to plant nutrition, different cell types accumulate certain elements in varying amounts within their storage vacuole. The role and mechanisms underlying cell-specific distribution of elements in plants is poorly understood. Scope The phenomenon of cell-specific elemental accumulation has been briefly reviewed previously, but recent technological advances with the potential to probe mechanisms underlying elemental compartmentation have warranted an updated evaluation. We have taken this opportunity to catalogue many of the studies, and techniques used for, recording cell-specific compartmentation of particular elements. More importantly, we use three case-study elements (Ca, Cd and Na) to highlight the basis of such phenomena in terms of their physiological implications and underpinning mechanisms; we also link such distributions to the expression of known ion or solute transporters. Conclusions Element accumulation patterns are clearly defined by expression of key ion or solute transporters. Although the location of element accumulation is fairly robust, alterations in expression of certain solute transporters, through genetic modifications or by growth under stress, result in perturbations to these patterns. However, redundancy or induced pleiotropic expression effects may complicate attempts to characterize the pathways that lead to cell-specific elemental distribution. Accumulation of one element often has consequences on the accumulation of others, which seems to be driven largely to maintain vacuolar and cytoplasmic osmolarity and charge balance, and also serves as a detoxification mechanism. Altered cell-specific transcriptomics can be shown, in part, to explain some of this compensation. PMID:20410048

  12. Current topics in plant biochemistry and physiology, 1986: Volume 5

    SciTech Connect

    Randall, D.D.; Miles, C.D.; Nelson, C.J.; Blevins, D.G.; Miernyk, J.A.

    1986-01-01

    These proceedings represent papers presented at the Fifth Annual Plant Biochemistry and Physiology Symposium held at the University of Missouri-Columbia, April 2-4, 1986, and hosted by the Interdisciplinary Plant Biochemistry and Physiology Group. The Interdisciplinary Group was organized to facilitate research and training through interdisciplinary and cooperative approaches to problems facing Plant Biochemistry and Physiology. This annual symposium is a means of maintaining an awareness of the advances in research in this field.

  13. Current topics in plant biochemistry and physiology: Volume 4: Proceedings

    SciTech Connect

    Randall, D.D.; Blevins, D.G.; Larson, R.L.

    1985-01-01

    These proceedings represent papers presented at the Fourth Annual Plant Biochemistry and Physiology Symposium held at the University of Missouri-Columbia, April 10-12, 1985 and hosted by the Interdisciplinary Plant Biochemistry and Physiology Group. This Interdisciplinary Group was organized to facilitate research and training through interdisciplinary and cooperative approaches to problems facing Plant Biochemistry and Physiology. A key objective of this group is to maintain an awareness of the advances in research in this field. This annual symposium is one means of meeting this objective. Topics are selected each year in three to five areas in order to broaden our individual horizons.

  14. Plant Sterols: Diversity, Biosynthesis, and Physiological Functions.

    PubMed

    Valitova, J N; Sulkarnayeva, A G; Minibayeva, F V

    2016-08-01

    Sterols, which are isoprenoid derivatives, are structural components of biological membranes. Special attention is now being given not only to their structure and function, but also to their regulatory roles in plants. Plant sterols have diverse composition; they exist as free sterols, sterol esters with higher fatty acids, sterol glycosides, and acylsterol glycosides, which are absent in animal cells. This diversity of types of phytosterols determines a wide spectrum of functions they play in plant life. Sterols are precursors of a group of plant hormones, the brassinosteroids, which regulate plant growth and development. Furthermore, sterols participate in transmembrane signal transduction by forming lipid microdomains. The predominant sterols in plants are β-sitosterol, campesterol, and stigmasterol. These sterols differ in the presence of a methyl or an ethyl group in the side chain at the 24th carbon atom and are named methylsterols or ethylsterols, respectively. The balance between 24-methylsterols and 24-ethylsterols is specific for individual plant species. The present review focuses on the key stages of plant sterol biosynthesis that determine the ratios between the different types of sterols, and the crosstalk between the sterol and sphingolipid pathways. The main enzymes involved in plant sterol biosynthesis are 3-hydroxy-3-methylglutaryl-CoA reductase, C24-sterol methyltransferase, and C22-sterol desaturase. These enzymes are responsible for maintaining the optimal balance between sterols. Regulation of the ratios between the different types of sterols and sterols/sphingolipids can be of crucial importance in the responses of plants to stresses.

  15. Electrical signals and their physiological significance in plants.

    PubMed

    Fromm, Jörg; Lautner, Silke

    2007-03-01

    Electrical excitability and signalling, frequently associated with rapid responses to environmental stimuli, are well known in some algae and higher plants. The presence of electrical signals, such as action potentials (AP), in both animal and plant cells suggested that plant cells, too, make use of ion channels to transmit information over long distances. In the light of rapid progress in plant biology during the past decade, the assumption that electrical signals do not only trigger rapid leaf movements in 'sensitive' plants such as Mimosa pudica or Dionaea muscipula, but also physiological processes in ordinary plants proved to be correct. Summarizing recent progress in the field of electrical signalling in plants, the present review will focus on the generation and propagation of various electrical signals, their ways of transmission within the plant body and various physiological effects.

  16. Physiology of Plants, Science (Experimental): 5315.41.

    ERIC Educational Resources Information Center

    Gunn, William C.

    This unit of instruction deals with the physiological activities of plants. Attention is focused on the principles which underlie the activities of the typical green land plant. Emphasis is placed on biological processes such as photosynthesis, water transport, light responses, mineral nutrition, reproduction, and growth. The prerequisite for…

  17. Physiological implications of arginine metabolism in plants

    PubMed Central

    Winter, Gudrun; Todd, Christopher D.; Trovato, Maurizio; Forlani, Giuseppe; Funck, Dietmar

    2015-01-01

    Nitrogen is a limiting resource for plant growth in most terrestrial habitats since large amounts of nitrogen are needed to synthesize nucleic acids and proteins. Among the 21 proteinogenic amino acids, arginine has the highest nitrogen to carbon ratio, which makes it especially suitable as a storage form of organic nitrogen. Synthesis in chloroplasts via ornithine is apparently the only operational pathway to provide arginine in plants, and the rate of arginine synthesis is tightly regulated by various feedback mechanisms in accordance with the overall nutritional status. While several steps of arginine biosynthesis still remain poorly characterized in plants, much wider attention has been paid to inter- and intracellular arginine transport as well as arginine-derived metabolites. A role of arginine as alternative source besides glutamate for proline biosynthesis is still discussed controversially and may be prevented by differential subcellular localization of enzymes. Apparently, arginine is a precursor for nitric oxide (NO), although the molecular mechanism of NO production from arginine remains unclear in higher plants. In contrast, conversion of arginine to polyamines is well documented, and in several plant species also ornithine can serve as a precursor for polyamines. Both NO and polyamines play crucial roles in regulating developmental processes as well as responses to biotic and abiotic stress. It is thus conceivable that arginine catabolism serves on the one hand to mobilize nitrogen storages, while on the other hand it may be used to fine-tune development and defense mechanisms against stress. This review summarizes the recent advances in our knowledge about arginine metabolism, with a special focus on the model plant Arabidopsis thaliana, and pinpoints still unresolved critical questions. PMID:26284079

  18. Root bacterial endophytes alter plant phenotype, but not physiology

    PubMed Central

    Weston, David J.; Pelletier, Dale A.; Jawdy, Sara S.; Classen, Aimée T.

    2016-01-01

    Plant traits, such as root and leaf area, influence how plants interact with their environment and the diverse microbiota living within plants can influence plant morphology and physiology. Here, we explored how three bacterial strains isolated from the Populus root microbiome, influenced plant phenotype. We chose three bacterial strains that differed in predicted metabolic capabilities, plant hormone production and metabolism, and secondary metabolite synthesis. We inoculated each bacterial strain on a single genotype of Populus trichocarpa and measured the response of plant growth related traits (root:shoot, biomass production, root and leaf growth rates) and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light–Asat, and saturating CO2–Amax). Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf growth rate up to 137% relative to non-inoculated control plants, evidence that plants respond to bacteria by modifying morphology. However, endophyte inoculation had no influence on total plant biomass and photosynthetic traits (net photosynthesis, chlorophyll content). In sum, bacterial inoculation did not significantly increase plant carbon fixation and biomass, but their presence altered where and how carbon was being allocated in the plant host. PMID:27833797

  19. Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology?

    PubMed

    Savage, Jessica A; Clearwater, Michael J; Haines, Dustin F; Klein, Tamir; Mencuccini, Maurizio; Sevanto, Sanna; Turgeon, Robert; Zhang, Cankui

    2016-04-01

    Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment.

  20. Plant senescence: Its biochemistry and physiology

    SciTech Connect

    Thomson, W.W.; Nothnagel, E.A.; Huffaker, R.C. )

    1987-01-01

    Considering the early phylogenetic appearance of functional xylem and phloem elements and the range of senescent processes expressed onto genetically, it becomes apparent that such processes are inextricably linked to the evolution, development, reproduction, form, and function of higher plants. The importance of these senescent processes to man are patently obvious since, in one form or another, these processes provide major sources of wood, fiber, and fuel, and are involved in seed development and grain and fruit ripening. To many, the results of senescent processes also have esthetic value including, for example, the grandeur of a Sequoia, the blaze of colors across a desert landscape covered in the spring by ephermal flowers, or the rich tones and panoramic splendor of a deciduous forest in autumn. Senescent processes are widespread, but varied in kind and degree, ranging from whole plants to individual tissues and cells. This symposium was organized primarily around cellular and biochemical aspects of senescence. A major emphasis was the view that senescent processes, and those which developmentally lead to senescence, are highly regulated with an underlying genetic component. Individual papers were processed separately for the database.

  1. Methods for determining the physiological state of a plant

    DOEpatents

    Kramer, David M.; Sacksteder, Colette

    2003-09-23

    The present invention provides methods for measuring a photosynthetic parameter. The methods of the invention include the steps of: (a) illuminating a plant leaf until steady-state photosynthesis is achieved; (b) subjecting the illuminated plant leaf to a period of darkness; (c) using a kinetic spectrophotometer or kinetic spectrophotometer/fluorimeter to collect spectral data from the plant leaf treated in accordance with steps (a) and (b); and (d) determining a photosynthetic parameter from the spectral data. In another aspect, the invention provides methods for determining the physiological state of a plant.

  2. Natural selection on plant physiological traits in an urban environment

    NASA Astrophysics Data System (ADS)

    Lambrecht, Susan C.; Mahieu, Stephanie; Cheptou, Pierre-Olivier

    2016-11-01

    Current rates of urbanization are creating new opportunities for studying urban plant ecology, but our knowledge of urban plant physiology lags behind that of other ecosystems. Moreover, higher temperatures, elevated CO2, and increased inorganic nitrogen deposition along with altered moisture regimes of urban as compared to rural areas creates a compelling analog for studying adaptations of plants to climate change. We grew plants under common conditions in a greenhouse to determine whether populations of Crepis sancta (Asteraceae) differed in phenological, morphological, and physiological traits. We also used a field experiment to test for natural selection on these traits in urban Montpellier, France. Urban plants flowered and senesced later than rural plants, and natural selection favored later phenology in the urban habitat. Natural selection also favored larger plants with more leaves, and increased photosynthesis and leaf nitrogen concentration. Ours is the first study to document selection on plant functional traits in an urban habitat and, as such, advances our understanding of urban plant ecology and possible adaptations to climate change.

  3. Urban plant physiology: adaptation-mitigation strategies under permanent stress.

    PubMed

    Calfapietra, Carlo; Peñuelas, Josep; Niinemets, Ülo

    2015-02-01

    Urban environments that are stressful for plant function and growth will become increasingly widespread in future. In this opinion article, we define the concept of 'urban plant physiology', which focuses on plant responses and long term adaptations to urban conditions and on the capacity of urban vegetation to mitigate environmental hazards in urbanized settings such as air and soil pollution. Use of appropriate control treatments would allow for studies in urban environments to be comparable to expensive manipulative experiments. In this opinion article, we propose to couple two approaches, based either on environmental gradients or manipulated gradients, to develop the concept of urban plant physiology for assessing how single or multiple environmental factors affect the key environmental services provided by urban forests.

  4. Circadian regulation of hormone signaling and plant physiology.

    PubMed

    Atamian, Hagop S; Harmer, Stacey L

    2016-08-01

    The survival and reproduction of plants depend on their ability to cope with a wide range of daily and seasonal environmental fluctuations during their life cycle. Phytohormones are plant growth regulators that are involved in almost every aspect of growth and development as well as plant adaptation to myriad abiotic and biotic conditions. The circadian clock, an endogenous and cell-autonomous biological timekeeper that produces rhythmic outputs with close to 24-h rhythms, provides an adaptive advantage by synchronizing plant physiological and metabolic processes to the external environment. The circadian clock regulates phytohormone biosynthesis and signaling pathways to generate daily rhythms in hormone activity that fine-tune a range of plant processes, enhancing adaptation to local conditions. This review explores our current understanding of the interplay between the circadian clock and hormone signaling pathways.

  5. Mineral nutrition of plants: a short history of plant physiology.

    PubMed

    Pennazio, Sergio

    2005-01-01

    The development of the knowledge on the mineral nutrition of plants begins between the 17th and 18th centuries when some European naturalists gave the first experimental evidences of what had been empirically known for about two millennia. The works of Hales and Ingenhousz were of absolute importance in relation to the transport of water and solutes, and assimilation of "fixed air" (carbon dioxide), respectively. The early chemistry introduced by Lavoisier benefited the first physiologists Senebier and De Saussure to reject the "theory of humus", which imposed the soil as the unique source of carbon. During the first half of the 19th century, Sprengel and Liebig investigated on the problems related to some indispensable mineral salts, while Boussingault and Ville attempted to prove the nitrogen fixation from air without giving any convincing evidence. Liebig was the pioneer of the agricultural chemistry: he epitomised the knowledge of that period by imposing the so-called "law of the minima", already acknowledged by Sprengel, and patronised the use of mineral fertilisers in Europe by devising several formulas of mineral manure. He, however, did not recognise the needs of external supplies of nitrogen salts for the crops, in open dispute with the English school of Lawes and Gilbert, who were instead convinced assertors of such needs. At the end of the 19th century Hellriegel showed that leguminous plants presenting peculiar nodules on their roots could really fix the gaseous nitrogen. From these nodules Beijerinck and Prazmowski isolated for the first time some bacteria which were recognised as the real agents fixing nitrogen. This discovery was of fundamental importance for plant nutrition, only second to the discovery of photosynthesis. Another basic contribution came from early research of Sachs on plants grown on aqueous solutions: these techniques allowed to impose the concept of "essential elements", which was fixed as a principle by Arnon and Stout in 1939

  6. The physiology of invasive plants in low-resource environments

    PubMed Central

    Funk, Jennifer L.

    2013-01-01

    While invasive plant species primarily occur in disturbed, high-resource environments, many species have invaded ecosystems characterized by low nutrient, water, and light availability. Species adapted to low-resource systems often display traits associated with resource conservation, such as slow growth, high tissue longevity, and resource-use efficiency. This contrasts with our general understanding of invasive species physiology derived primarily from studies in high-resource environments. These studies suggest that invasive species succeed through high resource acquisition. This review examines physiological and morphological traits of native and invasive species in low-resource environments. Existing data support the idea that species invading low-resource environments possess traits associated with resource acquisition, resource conservation or both. Disturbance and climate change are affecting resource availability in many ecosystems, and understanding physiological differences between native and invasive species may suggest ways to restore invaded ecosystems. PMID:27293610

  7. The physiology of invasive plants in low-resource environments.

    PubMed

    Funk, Jennifer L

    2013-01-01

    While invasive plant species primarily occur in disturbed, high-resource environments, many species have invaded ecosystems characterized by low nutrient, water, and light availability. Species adapted to low-resource systems often display traits associated with resource conservation, such as slow growth, high tissue longevity, and resource-use efficiency. This contrasts with our general understanding of invasive species physiology derived primarily from studies in high-resource environments. These studies suggest that invasive species succeed through high resource acquisition. This review examines physiological and morphological traits of native and invasive species in low-resource environments. Existing data support the idea that species invading low-resource environments possess traits associated with resource acquisition, resource conservation or both. Disturbance and climate change are affecting resource availability in many ecosystems, and understanding physiological differences between native and invasive species may suggest ways to restore invaded ecosystems.

  8. Molecular and physiological strategies to increase aluminum resistance in plants.

    PubMed

    Inostroza-Blancheteau, Claudio; Rengel, Zed; Alberdi, Miren; de la Luz Mora, María; Aquea, Felipe; Arce-Johnson, Patricio; Reyes-Díaz, Marjorie

    2012-03-01

    Aluminum (Al) toxicity is a primary limitation to plant growth on acid soils. Root meristems are the first site for toxic Al accumulation, and therefore inhibition of root elongation is the most evident physiological manifestation of Al toxicity. Plants may resist Al toxicity by avoidance (Al exclusion) and/or tolerance mechanisms (detoxification of Al inside the cells). The Al exclusion involves the exudation of organic acid anions from the root apices, whereas tolerance mechanisms comprise internal Al detoxification by organic acid anions and enhanced scavenging of free oxygen radicals. One of the most important advances in understanding the molecular events associated with the Al exclusion mechanism was the identification of the ALMT1 gene (Al-activated malate transporter) in Triticum aestivum root cells, which codes for a plasma membrane anion channel that allows efflux of organic acid anions, such as malate, citrate or oxalate. On the other hand, the scavenging of free radicals is dependent on the expression of genes involved in antioxidant defenses, such as peroxidases (e.g. in Arabidopsis thaliana and Nicotiana tabacum), catalases (e.g. in Capsicum annuum), and the gene WMnSOD1 from T. aestivum. However, other recent findings show that reactive oxygen species (ROS) induced stress may be due to acidic (low pH) conditions rather than to Al stress. In this review, we summarize recent findings regarding molecular and physiological mechanisms of Al toxicity and resistance in higher plants. Advances have been made in understanding some of the underlying strategies that plants use to cope with Al toxicity. Furthermore, we discuss the physiological and molecular responses to Al toxicity, including genes involved in Al resistance that have been identified and characterized in several plant species. The better understanding of these strategies and mechanisms is essential for improving plant performance in acidic, Al-toxic soils.

  9. Anatomy and physiology of plant conductive systems. Book chapter

    SciTech Connect

    McFarlane, C.

    1993-01-01

    Mathematical models considered in the book are representations of the physical features and chemical reactions that define interactions between plants and their environment. By centering attention on equations, it is easy to lose sight of the intricate and complex nature of the problem. The particular chapter describes the anatomy of important plant features and briefly discuss some physiological principles that will help to visualize and perceive the conditions which are represented in the models. Because of the many competing interactions, the fate of chemicals in the soil/plant/air environment is not obvious. Models were thus developed to intelligently integrate available knowledge, to increase understanding of the complex interactions, to aid in presentation of plant functions, and to help make predictions about chemical fate.

  10. Physiological roles of autophagy in plants: does plant autophagy have a pro-death function?

    PubMed

    Yoshimoto, Kohki

    2010-05-01

    Autophagy is an evolutionarily conserved intracellular process for vacuolar degradation of cytoplasmic components. Early morphological studies suggested that autophagy occurs in plant cells and predicted that autophagy has a variety of functions in plant growth and development. However, it is only since the identification of autophagy genes that the physiological roles of autophagy in plants have become apparent. Recent reverse genetic studies indicate that autophagy defects in higher plants result in early senescence and excessive immunity-related programmed cell death (PCD), irrespective of nutrient conditions, suggesting that plant autophagy has an important pro-survival function during these types of cell death. Further biochemical and pharmacological studies in combination with double mutant analyses revealed that excessive salicylic acid (SA) signaling is a major factor in autophagy-defective plant-dependent cell death and that the SA signal can induce autophagy. These results demonstrate a novel physiological function for plant autophagy that operates a negative feedback loop to modulate SA signaling.

  11. Small plants, large plants: the importance of plant size for the physiological ecology of vascular epiphytes.

    PubMed

    Zotz, G; Hietz, P; Schmidt, G

    2001-10-01

    Recently, a number of publications have reported that many physiological properties of vascular epiphytes are a function of plant size. This short review will summarize what is known to date about this phenomenon, describe the possible mechanism and will discuss the consequences for the present understanding of epiphyte biology. Size-related changes are also known from other plant groups and it is argued that close attention should be paid to the size of the organisms under study in order to understand the performance and survival of a species in the field. In the light of these findings, the results of many earlier studies on epiphyte ecophysiology are now difficult to interpret because essential information on the size of the specimens used is missing.

  12. Plant Ion Channels: Gene Families, Physiology, and Functional Genomics Analyses

    PubMed Central

    Ward, John M.; Mäser, Pascal; Schroeder, Julian I.

    2016-01-01

    Distinct potassium, anion, and calcium channels in the plasma membrane and vacuolar membrane of plant cells have been identified and characterized by patch clamping. Primarily owing to advances in Arabidopsis genetics and genomics, and yeast functional complementation, many of the corresponding genes have been identified. Recent advances in our understanding of ion channel genes that mediate signal transduction and ion transport are discussed here. Some plant ion channels, for example, ALMT and SLAC anion channel subunits, are unique. The majority of plant ion channel families exhibit homology to animal genes; such families include both hyperpolarization-and depolarization-activated Shaker-type potassium channels, CLC chloride transporters/channels, cyclic nucleotide–gated channels, and ionotropic glutamate receptor homologs. These plant ion channels offer unique opportunities to analyze the structural mechanisms and functions of ion channels. Here we review gene families of selected plant ion channel classes and discuss unique structure-function aspects and their physiological roles in plant cell signaling and transport. PMID:18842100

  13. Physiological responses in potato plants under continuous irradiation

    NASA Technical Reports Server (NTRS)

    Cao, W.; Tibbitts, T. W.

    1991-01-01

    The physiological responses of four potato (Solanum tuberosum L.) cultivars to continuous irradiation were determined in a controlled environment. Under a constant 18C and a constant photoperiod of 470 micromoles s-1 m-2 of photosynthetic photon flux, 'Denali' and 'Haig' grew well and produced large plant and tuber dry weights when harvested 56 days after transplanting. 'Kennebec' and 'Superior' were severely stunted, producing only 10% of the plant dry matter produced by 'Denali' and 'Haig'. The differences in leaf chlorophyll concentration and stomatal conductance were not consistent between these two groups of cultivars. The leaf net CO2 assimilation rates in 'Kennebec' and 'Superior' were lower, and intercellular CO2 partial pressures were higher than in 'Denali' and 'Haig'. These results indicate that inhibition of net CO2 assimilation in 'Kennebec' and 'Superior' was not due to a limiting amount of chlorophyll or to CO2 in the leaf tissues. Concentrations of starch in leaflets of 'Kennebec' and 'Superior' plants were only 10% of those in 'Denali' and 'Haig' plants, although soluble sugar concentrations were similar in the four cultivars. Therefore, the lower net CO2 assimilation rates in stunted 'Kennebec' and 'Superior' plants were not associated with an excess carbohydrate accumulation in the leaves.

  14. Human pathogens in plant biofilms: Formation, physiology, and detection.

    PubMed

    Ximenes, Eduardo; Hoagland, Lori; Ku, Seockmo; Li, Xuan; Ladisch, Michael

    2017-01-09

    Fresh produce, viewed as an essential part of a healthy life style is usually consumed in the form of raw or minimally processed fruits and vegetables, and is a potentially important source of food-borne human pathogenic bacteria and viruses. These are passed on to the consumer since the bacteria can form biofilms or otherwise populate plant tissues, thereby using plants as vectors to infect animal hosts. The life cycle of the bacteria in plants differs from those in animals or humans and results in altered physiochemical and biological properties (e.g., physiology, immunity, native microflora, physical barriers, mobility, and temperature). Mechanisms by which healthy plants may become contaminated by microorganisms, develop biofilms, and then pass on their pathogenic burden to people are explored in the context of hollow fiber microfiltration by which plant-derived microorganisms may be recovered and rapidly concentrated to facilitate study of their properties. Enzymes, when added to macerated plant tissues, hydrolyze or alter macromolecules that would otherwise foul hollow-fiber microfiltration membranes. Hence, microfiltration may be used to quickly increase the concentration of microorganisms to detectable levels. This review discusses microbial colonization of vegetables, formation and properties of biofilms, and how hollow fiber microfiltration may be used to concentrate microbial targets to detectable levels. The use of added enzymes helps to disintegrate biofilms and minimize hollow fiber membrane fouling, thereby providing a new tool for more time effectively elucidating mechanisms by which biofilms develop and plant tissue becomes contaminated with human pathogens. Biotechnol. Bioeng. 2016;9999: 1-16. © 2017 Wiley Periodicals, Inc.

  15. Emerging Use of Gene Expression Microarrays in Plant Physiology

    DOE PAGES

    Wullschleger, Stan D.; Difazio, Stephen P.

    2003-01-01

    Microarrays have become an important technology for the global analysis of gene expression in humans, animals, plants, and microbes. Implemented in the context of a well-designed experiment, cDNA and oligonucleotide arrays can provide highthroughput, simultaneous analysis of transcript abundance for hundreds, if not thousands, of genes. However, despite widespread acceptance, the use of microarrays as a tool to better understand processes of interest to the plant physiologist is still being explored. To help illustrate current uses of microarrays in the plant sciences, several case studies that we believe demonstrate the emerging application of gene expression arrays in plant physiology weremore » selected from among the many posters and presentations at the 2003 Plant and Animal Genome XI Conference. Based on this survey, microarrays are being used to assess gene expression in plants exposed to the experimental manipulation of air temperature, soil water content and aluminium concentration in the root zone. Analysis often includes characterizing transcript profiles for multiple post-treatment sampling periods and categorizing genes with common patterns of response using hierarchical clustering techniques. In addition, microarrays are also providing insights into developmental changes in gene expression associated with fibre and root elongation in cotton and maize, respectively. Technical and analytical limitations of microarrays are discussed and projects attempting to advance areas of microarray design and data analysis are highlighted. Finally, although much work remains, we conclude that microarrays are a valuable tool for the plant physiologist interested in the characterization and identification of individual genes and gene families with potential application in the fields of agriculture, horticulture and forestry.« less

  16. Flowering plant physiology triggered the expansion of tropical rainforest

    NASA Astrophysics Data System (ADS)

    Lee, J.; Boyce, C. K.

    2009-12-01

    Transpiration has long been known to feed precipitation, but unique hydraulic characteristics of flowering plants recently have been recognized to impart transpiration capacities dramatically higher than any other plants, living or extinct. Here we show through climate modeling that the replacement of angiosperm with non-angiosperm vegetation would result in a hotter, drier, and more seasonal Amazon basin—dry season length increases by 80 days over the eastern Amazon and overall area of everwet conditions decreases by a factor of five. Evolution of angiosperm physiology has uniquely facilitated spread of warm everwet forests and their enormous biodiversity, perhaps including their early Cenozoic expansion to extra-tropical latitudes. Divergent responses may be expected to general climate parameters and discrete environmental perturbations before and after evolution of angiosperm dominated ecosystems.

  17. Soil cadmium enrichment: Allocation and plant physiological manifestations.

    PubMed

    Irfan, Mohd; Hayat, Shamsul; Ahmad, Aqil; Alyemeni, Mohammed Nasser

    2013-01-01

    Cadmium (Cd) in soil is enriched through several leaky management agricultural practices and natural resources. Cd enriched soil is inevitable cause of nutritional stress besides Cd induced toxicity symptoms and physiological malfunctions. Redox signals shift toward oxidative stress which accelerates cellular damage and elicits defense mechanism at the cost of growth. Plants get enriched with this toxic, abundant and undesirable element through 'mineral uptake system' non-specifically. Different components and pathways have been marked cooperating in cellular sequestration and systemic localization of Cd, escaped from avoidance and efflux. Cd induced metabolic alteration led to electron leakage as ROS, reduced photosynthesis and carbon fixation. Compromised primary metabolism negatively feedbacks the plant growth, result into loss of potential crop yield.

  18. Soil cadmium enrichment: Allocation and plant physiological manifestations

    PubMed Central

    Irfan, Mohd; Hayat, Shamsul; Ahmad, Aqil; Alyemeni, Mohammed Nasser

    2012-01-01

    Cadmium (Cd) in soil is enriched through several leaky management agricultural practices and natural resources. Cd enriched soil is inevitable cause of nutritional stress besides Cd induced toxicity symptoms and physiological malfunctions. Redox signals shift toward oxidative stress which accelerates cellular damage and elicits defense mechanism at the cost of growth. Plants get enriched with this toxic, abundant and undesirable element through ‘mineral uptake system’ non-specifically. Different components and pathways have been marked cooperating in cellular sequestration and systemic localization of Cd, escaped from avoidance and efflux. Cd induced metabolic alteration led to electron leakage as ROS, reduced photosynthesis and carbon fixation. Compromised primary metabolism negatively feedbacks the plant growth, result into loss of potential crop yield. PMID:23961213

  19. Physiological changes in certain test plants under automobile exhaust pollution.

    PubMed

    Mandal, Madhumanjari

    2006-01-01

    Plants are the only living organisms which have to suffer a lot from automobile exhaust pollution because they remain static at their habitat. But such roadside plants like Nerium indicum Mill., Boerhaavia diffusa L., Amaranthus spinosus L., Cephalandra indica Naud., and Tabemaemontana divaricata L. can easily avoid the effects of air pollution by altering their physiological pathways pertaining to photosynthesis and respiration. Stomatal closure in Boerhaavia, Amaranthus, Cephlandra and stomatal clogging in Nerium and Tabemaemontana help these plants in preventing the entry of poisonous gases. The increased activity of the enzyme Phosphoenol Pyruvate Carboxylase (PEPCase) belonging to C4 pathway helps Nerium and Boerhaavia (both C3 plants) in carbon fixation under stress condition. Photorespiration is favoured in Amaranthus, Cephalandra and Tabernaemontana to compensate for the over production of ATP in them. Owing an inefficient gaseous exchange in Boerhaavia and Tabemaemontana, the activity of Glucose 6--Phosphate Dehydrogenase (G6-PD) also increases for the preferential shift to Pentose Phosphate Pathway to produce excess NADPH+H+ which are likely to re-oxidize by metabolic reactions not linked to electron transport chain.

  20. Evaluating physiological responses of plants to salinity stress

    PubMed Central

    Negrão, S.; Schmöckel, S. M.; Tester, M.

    2017-01-01

    Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making it difficult to study in toto. Instead, it is more tractable to dissect the plant’s response into traits that are hypothesized to be involved in the overall tolerance of the plant to salinity. Scope and conclusions We discuss how to quantify the impact of salinity on different traits, such as relative growth rate, water relations, transpiration, transpiration use efficiency, ionic relations, photosynthesis, senescence, yield and yield components. We also suggest some guidelines to assist with the selection of appropriate experimental systems, imposition of salinity stress, and obtaining and analysing relevant physiological data using appropriate indices. We illustrate how these indices can be used to identify relationships amongst the proposed traits to identify which traits are the most important contributors to salinity tolerance. Salinity tolerance is complex and involves many genes, but progress has been made in studying the mechanisms underlying a plant’s response to salinity. Nevertheless, several previous studies on salinity tolerance could have benefited from improved experimental design. We hope that this paper will provide pertinent information to researchers on performing proficient assays and interpreting results from salinity tolerance experiments. PMID:27707746

  1. Causes of Low and High Citation Potentials in Science: Citation Analysis of Biochemistry and Plant Physiology Journals.

    ERIC Educational Resources Information Center

    Marton, Janos

    1983-01-01

    Citation data of 16 biochemistry and plant physiology journals show that reasons for lower citation potentials of plant physiology articles are: (1) readership is narrower for plant physiology journals; (2) plant physiologists can cite fewer thematically relevant new articles; and (3) plant physiology research fields are more isolated. References…

  2. Physiological parameters controlling plant-atmosphere ammonia exchange

    NASA Astrophysics Data System (ADS)

    Schjoerring, Jan K.; Husted, Søren; Mattsson, Marie

    Recent advances in characterizing the influence of different physiological and environmental parameters on NH 3 exchange between plants and the atmosphere are presented. A central parameter in controlling the rate and direction of NH 3 fluxes is the NH 3 compensation point. It may vary from below 1 to over 20 nmol NH 3 mol -1 air. High compensation points seem to be a result of high tissue N status, rapid absorption of NH +4 from the root medium and/or low activity of glutamine synthetase, a key enzyme in NH +4 assimilation. These conditions cause the NH +4 concentration in leaf apoplast and leaf cells to increase. The NH 3 compensation point also depends on plant developmental stage with peaks in NH 3 emission related to leaf senescence and N remobilization. The leaf temperature has a profound influence on the NH 3 compensation point: an increase in temperature from 15 to 30°C may cause a plant to switch from being a strong sink for atmospheric NH 3 to being a significant NH 3 source. Stomatal conductance for NH 3 relative to that of water vapour increases with tissue N status and with leaf senescence. At a given leaf temperature, the NH 3 compensation point can be successfully predicted on basis of the pH and NH +4 concentration in the apoplast of the mesophyll cells.

  3. Physiological responses of plant leaves to atmospheric ammonia and ammonium

    NASA Astrophysics Data System (ADS)

    Pearson, J.; Soares, A.

    Misting of leaves of several plant species with 3 mM aqueous NH +4 at pH 5, or fumigation with 3000 μg m -3 gaseous NH 3 for 1 h, elicits similar biochemical and physiological changes in the species tested. The enzyme glutamine synthetase (GS) was shown to increase its activity in all species, while that of nitrate reductase (NR) was inhibited, at least in those species which possessed the ability to induce foliar NR. At the same time there were marked changes in organic anion concentrations, with malate and citrate in particular being reduced in concentration, following either NH +4 or NH 3 application to leaves. The changes in organic anions are also discussed in the light of pH regulation by the cell. A stimulation of photosynthesis was also evident when leaves were treated with either NH 3 or NH +4. It is argued that, because of the differences in solution chemistry of the two ammonia forms, the aqueous form applied at pH 5 and the gaseous form being an alkali in solution, these changes can only have occurred through the ability of the leaves to readily assimilate both forms of the ammonia. The biochemical changes might have potential as markers for the onset of physiological perturbation by atmospheric ammonia pollution, particularly changes in organic acid concentration; their use in an index of pollution stress is briefly discussed.

  4. Alteration of plant physiology by glyphosate and its by-product aminomethylphosphonic acid: an overview.

    PubMed

    Gomes, Marcelo P; Smedbol, Elise; Chalifour, Annie; Hénault-Ethier, Louise; Labrecque, Michel; Lepage, Laurent; Lucotte, Marc; Juneau, Philippe

    2014-09-01

    It is generally claimed that glyphosate kills undesired plants by affecting the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme, disturbing the shikimate pathway. However, the mechanisms leading to plant death may also be related to secondary or indirect effects of glyphosate on plant physiology. Moreover, some plants can metabolize glyphosate to aminomethylphosphonic acid (AMPA) or be exposed to AMPA from different environmental matrices. AMPA is a recognized phytotoxin, and its co-occurrence with glyphosate could modify the effects of glyphosate on plant physiology. The present review provides an overall picture of alterations of plant physiology caused by environmental exposure to glyphosate and its metabolite AMPA, and summarizes their effects on several physiological processes. It particularly focuses on photosynthesis, from photochemical events to C assimilation and translocation, as well as oxidative stress. The effects of glyphosate and AMPA on several plant physiological processes have been linked, with the aim of better understanding their phytotoxicity and glyphosate herbicidal effects.

  5. How to Do It. Plant Eco-Physiology: Experiments on Crassulacean Acid Metabolism, Using Minimal Equipment.

    ERIC Educational Resources Information Center

    Friend, Douglas J. C.

    1990-01-01

    Features of Crassulacean Acid Metabolism plants are presented. Investigations of a complex eco-physiological plant adaptation to the problems of growth in an arid environment are discussed. Materials and procedures for these investigations are described. (CW)

  6. Regulation by arbuscular mycorrhizae of the integrated physiological response to salinity in plants: new challenges in physiological and molecular studies.

    PubMed

    Ruiz-Lozano, Juan Manuel; Porcel, Rosa; Azcón, Charo; Aroca, Ricardo

    2012-06-01

    Excessive salt accumulation in soils is a major ecological and agronomical problem, in particular in arid and semi-arid areas. Excessive soil salinity affects the establishment, development, and growth of plants, resulting in important losses in productivity. Plants have evolved biochemical and molecular mechanisms that may act in a concerted manner and constitute the integrated physiological response to soil salinity. These include the synthesis and accumulation of compatible solutes to avoid cell dehydration and maintain root water uptake, the regulation of ion homeostasis to control ion uptake by roots, compartmentation and transport into shoots, the fine regulation of water uptake and distribution to plant tissues by the action of aquaporins, the reduction of oxidative damage through improved antioxidant capacity and the maintenance of photosynthesis at values adequate for plant growth. Arbuscular mycorrhizal (AM) symbiosis can help the host plants to cope with the detrimental effects of high soil salinity. There is evidence that AM symbiosis affects and regulates several of the above mentioned mechanisms, but the molecular bases of such effects are almost completely unknown. This review summarizes current knowledge about the effects of AM symbiosis on these physiological mechanisms, emphasizing new perspectives and challenges in physiological and molecular studies on salt-stress alleviation by AM symbiosis.

  7. Mechanism of Salinity Tolerance in Plants: Physiological, Biochemical, and Molecular Characterization

    PubMed Central

    Huang, Bingru

    2014-01-01

    Salinity is a major abiotic stress limiting growth and productivity of plants in many areas of the world due to increasing use of poor quality of water for irrigation and soil salinization. Plant adaptation or tolerance to salinity stress involves complex physiological traits, metabolic pathways, and molecular or gene networks. A comprehensive understanding on how plants respond to salinity stress at different levels and an integrated approach of combining molecular tools with physiological and biochemical techniques are imperative for the development of salt-tolerant varieties of plants in salt-affected areas. Recent research has identified various adaptive responses to salinity stress at molecular, cellular, metabolic, and physiological levels, although mechanisms underlying salinity tolerance are far from being completely understood. This paper provides a comprehensive review of major research advances on biochemical, physiological, and molecular mechanisms regulating plant adaptation and tolerance to salinity stress. PMID:24804192

  8. Evolutionary history underlies plant physiological responses to global change since the last glacial maximum.

    PubMed

    Becklin, Katie M; Medeiros, Juliana S; Sale, Kayla R; Ward, Joy K

    2014-06-01

    Assessing family- and species-level variation in physiological responses to global change across geologic time is critical for understanding factors that underlie changes in species distributions and community composition. Here, we used stable carbon isotopes, leaf nitrogen content and stomatal measurements to assess changes in leaf-level physiology in a mixed conifer community that underwent significant changes in composition since the last glacial maximum (LGM) (21 kyr BP). Our results indicate that most plant taxa decreased stomatal conductance and/or maximum photosynthetic capacity in response to changing conditions since the LGM. However, plant families and species differed in the timing and magnitude of these physiological responses, and responses were more similar within families than within co-occurring species assemblages. This suggests that adaptation at the level of leaf physiology may not be the main determinant of shifts in community composition, and that plant evolutionary history may drive physiological adaptation to global change over recent geologic time.

  9. Physiological changes induced by chromium stress in plants: an overview.

    PubMed

    Hayat, Shamsul; Khalique, Gulshan; Irfan, Mohammad; Wani, Arif Shafi; Tripathi, Bhumi Nath; Ahmad, Aqil

    2012-07-01

    This article presents an overview of the mechanism of chromium (Cr) stress in plants. Toxic effects of Cr on plant growth and development depend primarily on its valence state. Cr(VI) is highly toxic and mobile whereas Cr(III) is less toxic. Cr-induced oxidative stress involves induction of lipid peroxidation in plants that cause severe damage to cell membranes which includes degradation of photosynthetic pigments causing deterioration in growth. The potential of plants with the adequacy to accumulate or to stabilize Cr compounds for bioremediation of Cr contamination has gained engrossment in recent years.

  10. Physiology

    ERIC Educational Resources Information Center

    Kay, Ian

    2008-01-01

    Underlying recent developments in health care and new treatments for disease are advances in basic medical sciences. This edition of "Webwatch" focuses on sites dealing with basic medical sciences, with particular attention given to physiology. There is a vast amount of information on the web related to physiology. The sites that are included here…

  11. Remote Detection of Plant Physiological Responses to TNT Soil Contamination

    DTIC Science & Technology

    2010-01-01

    were significantly affected by TNT exposure at all treatment levels, and photosynthetic decline likely resulted from metabolic impairment rather than...exposure at all treatment levels, and photosynthetic decline likely resulted from metabolic impairment rather than stomatal closure as the experiment...Physiological measurements were significantly affect- ed by TNT exposure at all treatment levels, and photosynthetic decline likely resulted from

  12. Cell physiology of plants growing in cold environments.

    PubMed

    Lütz, Cornelius

    2010-08-01

    The life of plants growing in cold extreme environments has been well investigated in terms of morphological, anatomical, and ecophysiological adaptations. In contrast, long-term cellular or metabolic studies have been performed by only a few groups. Moreover, a number of single reports exist, which often represent just a glimpse of plant behavior. The review draws together the literature which has focused on tissue and cellular adaptations mainly to low temperatures and high light. Most studies have been done with European alpine plants; comparably well studied are only two phanerogams found in the coastal Antarctic. Plant adaptation in northern polar regions has always been of interest in terms of ecophysiology and plant propagation, but nowadays, this interest extends to the effects of global warming. More recently, metabolic and cellular investigations have included cold and UV resistance mechanisms. Low-temperature stress resistance in plants from cold environments reflects the climate conditions at the growth sites. It is now a matter of molecular analyses to find the induced genes and their products such as chaperones or dehydrins responsible for this resistance. Development of plants under snow or pollen tube growth at 0 degrees C shows that cell biology is needed to explain the stability and function of the cytoskeleton. Many results in this field are based on laboratory studies, but several publications show that it is not difficult to study cellular mechanisms with the plants adapted to a natural stress. Studies on high light and UV loads may be split in two parts. Many reports describe natural UV as harmful for the plants, but these studies were mainly conducted by shielding off natural UV (as controls). Other experiments apply additional UV in the field and have had practically no negative impact on metabolism. The latter group is supported by the observations that green overwintering plants increase their flavonoids under snow even in the absence of

  13. Air and the origin of the experimental plant physiology.

    PubMed

    Pennazio, Sergio

    2005-01-01

    It is well known that oxygen and carbon dioxide are two chemicals which enter the plant metabolism as nutrients. The bases of this nowadays obvious statement were placed in the 18th century by means of the works of ingenious naturalists such as Robert Boyle, Stephen Hales, Joseph Priestley, Jam Ingenhousz, Lazzaro Spallanzani and Theodore De Saussure. Till the end of the 17th century, the atmospheric air was considered as an ineffable spirit, the function of which was of physical nature. Boyle was the first naturalist to admit the possibility that respiration were an exchange of vapours occurring in the blood. Stephen Hales realised that air could be fixed by plants under the influence of solar light. Priestley showed that plants could regenerate the bad air making it breathable. Ingenhousz demonstrated that the green parts of plants performed the complete purification of air only under the influence of the light. Spallanzani discovered that plants respire and guessed that the good air (oxygen) originated from the fixed air (carbon dioxide). Finally, Theodore De Saussure showed that plants were able to adsorb carbon dioxide and to release oxygen in a proportional air. All these discoveries benefited of the results coming from investigations of scholars of the so-called "pneumatic chemistry" (Boyle himself, George Ernst Stahl, Joseph Black, Priestley himself, and many more others. But among all the eminent scientists above mentioned stands out the genius of Antoine Laurent Lavoisier, who revolutionised the chemistry of the 18th century ferrying it towards the modern chemistry.

  14. ROS and RNS in plant physiology: an overview.

    PubMed

    Del Río, Luis A

    2015-05-01

    The production of reactive oxygen species (ROS) is the unavoidable consequence of aerobic life. ROS is a collective term that includes both oxygen radicals, like superoxide (O 2. -) and hydroxyl (·OH) radicals, and other non-radicals such as hydrogen peroxide (H2O2), singlet oxygen ((1)O2 or (1)Δg), etc. In plants, ROS are produced in different cell compartments and are oxidizing species, particularly hydroxyl radicals and singlet oxygen, that can produce serious damage in biological systems (oxidative stress). However, plant cells also have an array of antioxidants which, normally, can scavenge the excess oxidants produced and so avoid deleterious effects on the plant cell bio-molecules. The concept of 'oxidative stress' was re-evaluated in recent years and the term 'oxidative signalling' was created. This means that ROS production, apart from being a potentially harmful process, is also an important component of the signalling network that plants use for their development and for responding to environmental challenges. It is known that ROS play an important role regulating numerous biological processes such as growth, development, response to biotic and environmental stresses, and programmed cell death. The term reactive nitrogen species (RNS) includes radicals like nitric oxide (NO· ) and nitric dioxide (NO2.), as well as non-radicals such as nitrous acid (HNO2) and dinitrogen tetroxide (N2O4), among others. RNS are also produced in plants although the generating systems have still not been fully characterized. Nitric oxide (NO·) has an important function as a key signalling molecule in plant growth, development, and senescence, and RNS, like ROS, also play an important role as signalling molecules in the response to environmental (abiotic) stress. Similarly, NO· is a key mediator, in co-operation with ROS, in the defence response to pathogen attacks in plants. ROS and RNS have been demonstrated to have an increasingly important role in biology and medicine.

  15. Physiological Functions of the COPI Complex in Higher Plants.

    PubMed

    Ahn, Hee-Kyung; Kang, Yong Won; Lim, Hye Min; Hwang, Inhwan; Pai, Hyun-Sook

    2015-10-01

    COPI vesicles are essential to the retrograde transport of proteins in the early secretory pathway. The COPI coatomer complex consists of seven subunits, termed α-, β-, β'-, γ-, δ-, ε-, and ζ-COP, in yeast and mammals. Plant genomes have homologs of these subunits, but the essentiality of their cellular functions has hampered the functional characterization of the subunit genes in plants. Here we have employed virus-induced gene silencing (VIGS) and dexamethasone (DEX)-inducible RNAi of the COPI subunit genes to study the in vivo functions of the COPI coatomer complex in plants. The β'-, γ-, and δ-COP subunits localized to the Golgi as GFP-fusion proteins and interacted with each other in the Golgi. Silencing of β'-, γ-, and δ-COP by VIGS resulted in growth arrest and acute plant death in Nicotiana benthamiana, with the affected leaf cells exhibiting morphological markers of programmed cell death. Depletion of the COPI subunits resulted in disruption of the Golgi structure and accumulation of autolysosome-like structures in earlier stages of gene silencing. In tobacco BY-2 cells, DEX-inducible RNAi of β'-COP caused aberrant cell plate formation during cytokinesis. Collectively, these results suggest that COPI vesicles are essential to plant growth and survival by maintaining the Golgi apparatus and modulating cell plate formation.

  16. Physiological responses of Vicia faba plants to sulfur dioxide

    SciTech Connect

    Nandi, P.K.; Agrawal, M.; Agrawal, S.B.; Rao, D.N. )

    1990-02-01

    Exposure of broad bean (Vicia faba L.) plants to 270 +/- 32 and 670 +/- 45 micrograms m 3SO{sub 2} for 1.5 hr daily between 40 and 85 days of their ages resulted in an increase in their transpiration rate, water saturation deficit, phenol content, and peroxidase activity and a decrease in protein content. With the increase in number of exposures of plants to SO{sub 2}, chlorotic and brown, necrotic visible injury signs were also developed in leaves. It was further noted that the magnitude of undesirable biochemical changes, which possibly helped in the formation of new pigment characteristic of necrotic tissue of SO{sub 2}-exposed plants, was not totally dependent on the pollutant concentration.

  17. What Has Natural Variation Taught Us about Plant Development, Physiology, and Adaptation?

    PubMed Central

    Alonso-Blanco, Carlos; Aarts, Mark G.M.; Bentsink, Leonie; Keurentjes, Joost J.B.; Reymond, Matthieu; Vreugdenhil, Dick; Koornneef, Maarten

    2009-01-01

    Nearly 100 genes and functional polymorphisms underlying natural variation in plant development and physiology have been identified. In crop plants, these include genes involved in domestication traits, such as those related to plant architecture, fruit and seed structure and morphology, as well as yield and quality traits improved by subsequent crop breeding. In wild plants, comparable traits have been dissected mainly in Arabidopsis thaliana. In this review, we discuss the major contributions of the analysis of natural variation to our understanding of plant development and physiology, focusing in particular on the timing of germination and flowering, plant growth and morphology, primary metabolism, and mineral accumulation. Overall, functional polymorphisms appear in all types of genes and gene regions, and they may have multiple mutational causes. However, understanding this diversity in relation to adaptation and environmental variation is a challenge for which tools are now available. PMID:19574434

  18. Effects of rare earth elements and REE-binding proteins on physiological responses in plants.

    PubMed

    Liu, Dongwu; Wang, Xue; Chen, Zhiwei

    2012-02-01

    Rare earth elements (REEs), which include 17 elements in the periodic table, share chemical properties related to a similar external electronic configuration. REEs enriched fertilizers have been used in China since the 1980s. REEs could enter the cell and cell organelles, influence plant growth, and mainly be bound with the biological macromolecules. REE-binding proteins have been found in some plants. In addition, the chlorophyll activities and photosynthetic rate can be regulated by REEs. REEs could promote the protective function of cell membrane and enhance the plant resistance capability to stress produced by environmental factors, and affect the plant physiological mechanism by regulating the Ca²⁺ level in the plant cells. The focus of present review is to describe how REEs and REE-binding proteins participate in the physiological responses in plants.

  19. Molecular and physiological mechanisms of plant tolerance to toxic metals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants have evolved a myriad of adaptive mechanisms based on a number of genes to deal with the different toxic metals they encounter in the soils worldwide. These genes encode a range of different metal and organic compound transporters and enzyme pathways for the synthesis of metal detoxifying lig...

  20. Regulating Intracellular Calcium in Plants: From Molecular Genetics to Physiology

    SciTech Connect

    Heven Sze

    2008-06-22

    To grow, develop, adapt, and reproduce, plants have evolved mechanisms to regulate the uptake, translocation and sorting of calcium ions into different cells and subcellular compartments. Yet how plants accomplish this remarkable feat is still poorly understood. The spatial and temporal changes in intracellular [Ca2+] during growth and during responses to hormonal and environmental stimuli indicate that Ca2+ influx and efflux transporters are diverse and tightly regulated in plants. The specific goals were to determine the biological roles of multiple Ca pumps (ECAs) in the model plant Arabidopsis thaliana. We had pioneered the use of K616 yeast strain to functionally express plant Ca pumps, and demonstrated two distinct types of Ca pumps in plants (Sze et al., 2000. Annu Rev Plant Biol. 51,433). ACA2 represented one type that was auto-inhibited by the N-terminal region and stimulated by calmodulin. ECA1 represented another type that was not sensitive to calmodulin and phylogenetically distinct from ACAs. The goal to determine the biological roles of multiple ECA-type Ca pumps in Arabidopsis has been accomplished. Although we demonstrated ECA1 was a Ca pump by functional expression in yeast, the in vivo roles of ECAs was unclear. A few highlights are described. ECA1 and/or ECA4 are Ca/Mn pumps localized to the ER and are highly expressed in all cell types. Using homozygous T-DNA insertional mutants of eca1, we demonstrated that the ER-bound ECA1 supports growth and confers tolerance of plants growing on medium low in Ca or containing toxic levels of Mn. This is the first genetic study to determine the in vivo function of a Ca pump in plants. A phylogenetically distinct ECA3 is also a Ca/Mn pump that is localized to endosome, such as post-Golgi compartments. Although it is expressed at lower levels than ECA1, eca3 mutants are impaired in Ca-dependent root growth and in pollen tube elongation. Increased secretion of wall proteins in mutants suggests that Ca and Mn

  1. Dominant role of plant physiology in trend and variability of gross primary productivity in North America

    PubMed Central

    Zhou, Sha; Zhang, Yao; Ciais, Philippe; Xiao, Xiangming; Luo, Yiqi; Caylor, Kelly K.; Huang, Yuefei; Wang, Guangqian

    2017-01-01

    Annual gross primary productivity (GPP) varies considerably due to climate-induced changes in plant phenology and physiology. However, the relative importance of plant phenology and physiology on annual GPP variation is not clear. In this study, a Statistical Model of Integrated Phenology and Physiology (SMIPP) was used to evaluate the relative contributions of maximum daily GPP (GPPmax) and the start and end of growing season (GSstart and GSend) to annual GPP variability, using a regional GPP product in North America during 2000–2014 and GPP data from 24 AmeriFlux sites. Climatic sensitivity of the three indicators was assessed to investigate the climate impacts on plant phenology and physiology. The SMIPP can explain 98% of inter-annual variability of GPP over mid- and high latitudes in North America. The long-term trend and inter-annual variability of GPP are dominated by GPPmax both at the ecosystem and regional scales. During warmer spring and autumn, GSstart is advanced and GSend delayed, respectively. GPPmax responds positively to summer temperature over high latitudes (40–80°N), but negatively in mid-latitudes (25–40°N). This study demonstrates that plant physiology, rather than phenology, plays a dominant role in annual GPP variability, indicating more attention should be paid to physiological change under futher climate change. PMID:28145496

  2. Dominant role of plant physiology in trend and variability of gross primary productivity in North America

    NASA Astrophysics Data System (ADS)

    Zhou, Sha; Zhang, Yao; Ciais, Philippe; Xiao, Xiangming; Luo, Yiqi; Caylor, Kelly K.; Huang, Yuefei; Wang, Guangqian

    2017-02-01

    Annual gross primary productivity (GPP) varies considerably due to climate-induced changes in plant phenology and physiology. However, the relative importance of plant phenology and physiology on annual GPP variation is not clear. In this study, a Statistical Model of Integrated Phenology and Physiology (SMIPP) was used to evaluate the relative contributions of maximum daily GPP (GPPmax) and the start and end of growing season (GSstart and GSend) to annual GPP variability, using a regional GPP product in North America during 2000–2014 and GPP data from 24 AmeriFlux sites. Climatic sensitivity of the three indicators was assessed to investigate the climate impacts on plant phenology and physiology. The SMIPP can explain 98% of inter-annual variability of GPP over mid- and high latitudes in North America. The long-term trend and inter-annual variability of GPP are dominated by GPPmax both at the ecosystem and regional scales. During warmer spring and autumn, GSstart is advanced and GSend delayed, respectively. GPPmax responds positively to summer temperature over high latitudes (40–80°N), but negatively in mid-latitudes (25–40°N). This study demonstrates that plant physiology, rather than phenology, plays a dominant role in annual GPP variability, indicating more attention should be paid to physiological change under futher climate change.

  3. Physiological Response of Plants to Temporary Changes in Gravity Conditions

    NASA Astrophysics Data System (ADS)

    Pandolfi, Camilla; Mugnai, Sergio; Masi, Elisa; Azzarello, Elisa; Voigt, Boris; Baluska, Frantisek; Volkmann, Dieter; Mancuso, Stefano

    Gravity is the main factor that influences the direction of growth of plant organs, and has also a direct effect on the plant metabolism. When an organ, mainly roots, is turned by between 0 (vertical) and 90 (horizontal), the change of orientation is perceived by its organs producing the so-called gravitropic reaction, which involves a strong metabolic response. In order to study these reaction in real microgravity conditions, some experiments have been set up during six ESA parabolic flight campaign. Oxygen concentration in the solution, in which roots of Zea mays were placed, have been constantly monitored during normal, hyper-and microgravity conditions. An evident burst in oxygen fluxes started just 2.0 0.5 s after the imposition of microgravity conditions. No significant changes were noticed neither in normal nor in hyper-gravity conditions. These measurements were done using oxymeters, that revealed the onset of long lasting oxygen bursts appearing only during microgravity. Although the chemical nature of these oxygen bursts is still unknown, they may implicate a strong generation of reactive oxygen species as they exactly match the microgravity situation. Thus, our data strongly sug-gest that the sensing mechanism is not related to a general mechano-stress, which was imposed also during hypergravity, but is very specific of the microgravity situation. Moreover, it is well-known that stress rapidly induces reactive oxygen bursts which are associated with oxygen influx and reactive oxygen efflux from stressed plant tissues. Accordingly, our data indicate that microgravity represents a stress situation for plants, especially for root apices, and these bursts, probably ROS, are initiating and integrating adaptive responses of plant roots which resemble other unrelated stress situations. To validate this hypothesis we added to our ex-perimental set-up two very sensitive selective microelectrodes for H2 O2 and NO, and, even if the parabolic flights are not

  4. Polyploidy in aspen alters plant physiology and drought sensitivity

    NASA Astrophysics Data System (ADS)

    Greer, B.; Still, C. J.; Brooks, J. R.; Meinzer, F. C.

    2015-12-01

    Polyploids of quaking aspen (Populus tremuloides) may be better suited to dry climatic conditions than diploids. However, the expression of diploid and polyploid functional traits, including water use efficiency, an important component of drought avoidance and tolerance, are not well understood in quaking aspen. In this study diploid and triploid aspen clones' leaf, ramet, and stand functional traits were measured near the Rocky Mountain Biological Laboratory in Gothic, Colorado. The physiology of diploid and triploid aspen, including leaf size, chlorophyll content, stomatal size and density and stomatal conductance, as well as growth rates and carbon isotope discrimination in response to climate (measured in tree rings), were found to be significantly different between ploidy levels. These findings demonstrate different sensitivities of diploid and triploid clones to drought related climate stressors which may impact strategies for aspen forest management and conservation.

  5. Physiological Response of Plants Grown on Porous Ceramic Tubes

    NASA Technical Reports Server (NTRS)

    Tsao, David; Okos, Martin

    1997-01-01

    This research involves the manipulation of the root-zone water potential for the purposes of discriminating the rate limiting step in the inorganic nutrient uptake mechanism utilized by higher plants. This reaction sequence includes the pathways controlled by the root-zone conditions such as water tension and gradient concentrations. Furthermore, plant based control mechanisms dictated by various protein productions are differentiated as well. For the nutrients limited by the environmental availability, the kinetics were modeled using convection and diffusion equations. Alternatively, for the nutrients dependent upon enzyme manipulations, the uptakes are modeled using Michaelis-Menten kinetics. In order to differentiate between these various mechanistic steps, an experimental apparatus known as the Porous Ceramic Tube - Nutrient Delivery System (PCT-NDS) was used. Manipulation of the applied suction pressure circulating a nutrient solution through this system imposes a change in the matric component of the water potential. This compensates for the different osmotic components of water potential dictated by nutrient concentration. By maintaining this control over the root-zone conditions, the rate limiting steps in the uptake of the essential nutrients into tomato plants (Lycopersicon esculentum cv. Cherry Elite) were differentiated. Results showed that the uptake of some nutrients were mass transfer limited while others were limited by the enzyme kinetics. Each of these were adequately modeled with calculations and discussions of the parameter estimations provided.

  6. Physiological and gene expression responses of sunflower (Helianthus annuus L.) plants differ according to irrigation placement.

    PubMed

    Aguado, Ana; Capote, Nieves; Romero, Fernando; Dodd, Ian C; Colmenero-Flores, José M

    2014-10-01

    To investigate effects of soil moisture heterogeneity on plant physiology and gene expression in roots and leaves, three treatments were implemented in sunflower plants growing with roots split between two compartments: a control (C) treatment supplying 100% of plant evapotranspiration, and two treatments receiving 50% of plant evapotranspiration, either evenly distributed to both compartments (deficit irrigation - DI) or unevenly distributed to ensure distinct wet and dry compartments (partial rootzone drying - PRD). Plants receiving the same amount of water responded differently under the two irrigation systems. After 3 days, evapotranspiration was similar in C and DI, but 20% less in PRD, concomitant with decreased leaf water potential (Ψleaf) and increased leaf xylem ABA concentration. Six water-stress responsive genes were highly induced in roots growing in the drying soil compartment of PRD plants, and their expression was best correlated with local soil water content. On the other hand, foliar gene expression differed significantly from that of the root and correlated better with xylem ABA concentration and Ψleaf. While the PRD irrigation strategy triggered stronger physiological and molecular responses, suggesting a more intense and systemic stress reaction due to local dehydration of the dry compartment of PRD plants, the DI strategy resulted in similar water savings without strongly inducing these responses. Correlating physiological and molecular responses in PRD/DI plants may provide insights into the severity and location of water deficits and may enable a better understanding of long-distance signalling mechanisms.

  7. The gravitational plant physiology facility-Description of equipment developed for biological research in spacelab

    NASA Technical Reports Server (NTRS)

    Heathcote, D. G.; Chapman, D. K.; Brown, A. H.; Lewis, R. F.

    1994-01-01

    In January 1992, the NASA Suttle mission STS 42 carried a facility designed to perform experiments on plant gravi- and photo-tropic responses. This equipment, the Gravitational Plant Physiology Facility (GPPF) was made up of a number of interconnected units mounted within a Spacelab double rack. The details of these units and the plant growth containers designed for use in GPPF are described. The equipment functioned well during the mission and returned a substantial body of time-lapse video data on plant responses to tropistic stimuli under conditions of orbital microgravity. GPPF is maintained by NASA Ames Research Center, and is flight qualifiable for future spacelab missions.

  8. The Gravitational Plant Physiology Facility--description of equipment developed for biological research in Spacelab.

    PubMed

    Heathcote, D G; Chapman, D K; Brown, A H; Lewis, R F

    1994-09-01

    In January 1992, the NASA Shuttle mission STS 42 carried a facility designed to perform experiments on plant gravi- and photo-tropic responses. This equipment, the Gravitational Plant Physiology Facility (GPPF) was made up of a number of interconnected units mounted within a Spacelab double rack. The details of these units and the plant growth containers designed for use in GPPF are described. The equipment functioned well during the mission and returned a substantial body of time-lapse video data on plant responses to tropistic stimuli under conditions of orbital microgravity. GPPF is maintained by NASA Ames Research Center, and is flight qualifiable for future Spacelab missions.

  9. Potato type I and II proteinase inhibitors: modulating plant physiology and host resistance.

    PubMed

    Turra, David; Lorito, Matteo

    2011-08-01

    Serine protease inhibitors (PIs) are a large and complex group of plant proteins. Members of the potato type I (Pin1) and II (Pin2) proteinase inhibitor families are among the first and most extensively characterized plant PIs. Many insects and phytopathogenic microorganisms use intracellular and extracellular serine proteases playing important roles in pathogenesis. Plants, however, are able to fight these pathogens through the activation of an intricate defence system that leads to the accumulation of various PIs, including Pin1 and Pin2. Several transgenic plants over-expressing members of the Pin1 and Pin2 families have been obtained in the last twenty years and their enhanced defensive capabilities demonstrated against insects, fungi and bacteria. Furthermore, Pin1 and Pin2 genetically engineered plants showed altered regulation of different plant physiological processes (e.g., dehydratation response, programmed cell death, plant growth, trichome density and branching), supporting an endogenous role in various plant species in addition to the well established defensive one. This review summarizes the current knowledge about Pin1 and Pin2 structure, the role of these proteins in plant defence and physiology, and their potential exploitation in biotechnology.

  10. The phytotronist and the phenotype: plant physiology, Big Science, and a Cold War biology of the whole plant.

    PubMed

    Munns, David P D

    2015-04-01

    This paper describes how, from the early twentieth century, and especially in the early Cold War era, the plant physiologists considered their discipline ideally suited among all the plant sciences to study and explain biological functions and processes, and ranked their discipline among the dominant forms of the biological sciences. At their apex in the late-1960s, the plant physiologists laid claim to having discovered nothing less than the "basic laws of physiology." This paper unwraps that claim, showing that it emerged from the construction of monumental big science laboratories known as phytotrons that gave control over the growing environment. Control meant that plant physiologists claimed to be able to produce a standard phenotype valid for experimental biology. Invoking the standards of the physical sciences, the plant physiologists heralded basic biological science from the phytotronic produced phenotype. In the context of the Cold War era, the ability to pursue basic science represented the highest pinnacle of standing within the scientific community. More broadly, I suggest that by recovering the history of an underappreciated discipline, plant physiology, and by establishing the centrality of the story of the plant sciences in the history of biology can historians understand the massive changes wrought to biology by the conceptual emergence of the molecular understanding of life, the dominance of the discipline of molecular biology, and the rise of biotechnology in the 1980s.

  11. Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.

    PubMed

    Bokhorst, Stef; Bjerke, Jarle W; Davey, Matthew P; Taulavuori, Kari; Taulavuori, Erja; Laine, Kari; Callaghan, Terry V; Phoenix, Gareth K

    2010-10-01

    Insulation provided by snow cover and tolerance of freezing by physiological acclimation allows Arctic plants to survive cold winter temperatures. However, both the protection mechanisms may be lost with winter climate change, especially during extreme winter warming events where loss of snow cover from snow melt results in exposure of plants to warm temperatures and then returning extreme cold in the absence of insulating snow. These events cause considerable damage to Arctic plants, but physiological responses behind such damage remain unknown. Here, we report simulations of extreme winter warming events using infrared heating lamps and soil warming cables in a sub-Arctic heathland. During these events, we measured maximum quantum yield of photosystem II (PSII), photosynthesis, respiration, bud swelling and associated bud carbohydrate changes and lipid peroxidation to identify physiological responses during and after the winter warming events in three dwarf shrub species: Empetrum hermaphroditum, Vaccinium vitis-idaea and Vaccinium myrtillus. Winter warming increased maximum quantum yield of PSII, and photosynthesis was initiated for E. hermaphroditum and V. vitis-idaea. Bud swelling, bud carbohydrate decreases and lipid peroxidation were largest for E. hermaphroditum, whereas V. myrtillus and V. vitis-idaea showed no or less strong responses. Increased physiological activity and bud swelling suggest that sub-Arctic plants can initiate spring-like development in response to a short winter warming event. Lipid peroxidation suggests that plants experience increased winter stress. The observed differences between species in physiological responses are broadly consistent with interspecific differences in damage seen in previous studies, with E. hermaphroditum and V. myrtillus tending to be most sensitive. This suggests that initiation of spring-like development may be a major driver in the damage caused by winter warming events that are predicted to become more

  12. Lack of physiological improvement in performance of Callosamia promethea larvae on local host plant favorites.

    PubMed

    Scriber, J Mark; Potter, Juliana; Johnson, Kelly

    1991-04-01

    As a species, the promethea silkmoth, Callosamia promethea (Saturniidae: Lepidoptera) exhibits a wide host range on 6-10 families of plants, although specific populations are known to have local foodplant favorites. We tested the hypothesis that larvae from a particular host plant lineage would show physiological adaptations to this host compared with larvae from other host plant lineages. We found no evidence that larval survival and growth was any better for larvae fed the natural plant of the parental population than for larvae from other host lineages. These natural host lineages include: black cherry (Prunus serotina Ehrh.), tuliptree (Liriodendron tulipifera L.), sassafras (Sassafras albidum (Nutt.) Nees) and spicebush (Lindera benzoin (L.) Blume). The only apparent manifestation of physiological specialization was the inability of tuliptree lineages of C. promethea to survive on paper birch (Betula papyrifera Marsh), although this may reflect the geographical pattern of adaptation to birch, rather than a negative correlation with adaptation to tuliptree. These results suggest that for C. promethea larvae, growth performance and survival is primarily influenced by plant nutritional quality, rather than physiological adaptations to the locally preferred host plant.

  13. Phytotoxicity assessment of atrazine on growth and physiology of three emergent plants.

    PubMed

    Wang, Qinghai; Que, Xiaoe; Zheng, Ruilun; Pang, Zuo; Li, Cui; Xiao, Bo

    2015-07-01

    The emergent plants Acorus calamus, Lythrum salicaria, and Scirpus tabernaemontani were exposed to atrazine for 15, 30, 45, and 60 days in a hydroponic system. Effects were evaluated investigating plant growth, chlorophyll (Chl) content, peroxidase (POD) activity, and malondialdehyde (MDA) content. Results showed that selected plants survived in culture solution with atrazine ≤8 mg L(-1), but relative growth rates decreased significantly in the first 15-day exposure. Chla content decreased, but MDA increased with increasing atrazine concentration. S. tabernaemontani was the most insensitive species, followed by A. calamus and L.salicaria. The growth indicators exhibited significant changes in the early stage of atrazine exposure; subsequently, the negative impacts weakened and disappeared. Plant growth may be more representative of emergent plant fitness than physiological endpoints in toxicity assessment of herbicides to emergent plants.

  14. The medical plant butterbur (Petasites): analytical and physiological (re)view.

    PubMed

    Aydın, Ahmet Alper; Zerbes, Valentin; Parlar, Harun; Letzel, Thomas

    2013-03-05

    Butterbur (Petasites) is an ancient plant which has been used for medical and edible purposes with its spasmolytic agents. However, toxic alkaloid content of the plant limits its direct usage. The paper covers the pyrrolizidine alkaloids (PAs) and butterbur themes in detail in order to display the outline of alkaloid-free plant extract production for medical and edible purposes. The toxic PAs and medicinal constituents of the plant are described with emphasis on analytics, physiological effects and published patent data on alkaloid free extract production. The analytics is based on several commonly used analytical methods including liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry and enzyme linked immunoassay analysis of PAs and N-oxides based on published literature data of butterbur. The analyses of major medicinal constituents of butterbur are given and the physiological effects of these compounds have been discussed to attract attention to the importance of alkaloid-free extract production. The concentration distributions of the medicinal constituents and toxic PAs in different parts of the plant and the outcomes of the published patent data provide comprehensive information for proper plant raw-material selection and production of alkaloid-free butterbur extracts. The review is intended to guide researchers interested in medical plant extracts by providing comprehensive data on the medical plant butterbur and its chemical constituents.

  15. Plant Physiological, Morphological and Yield-Related Responses to Night Temperature Changes across Different Species and Plant Functional Types.

    PubMed

    Jing, Panpan; Wang, Dan; Zhu, Chunwu; Chen, Jiquan

    2016-01-01

    Land surface temperature over the past decades has shown a faster warming trend during the night than during the day. Extremely low night temperatures have occurred frequently due to the influence of land-sea thermal difference, topography and climate change. This asymmetric night temperature change is expected to affect plant ecophysiology and growth, as the plant carbon consumption processes could be affected more than the assimilation processes because photosynthesis in most plants occurs during the daytime whereas plant respiration occurs throughout the day. The effects of high night temperature (HNT) and low night temperature (LNT) on plant ecophysiological and growing processes and how the effects vary among different plant functional types (PFTs) have not been analyzed extensively. In this meta-analysis, we examined the effect of HNT and LNT on plant physiology and growth across different PFTs and experimental settings. Plant species were grouped according to their photosynthetic pathways (C3, C4, and CAM), growth forms (herbaceous, woody), and economic purposes (crop, non-crop). We found that HNT and LNT both had a negative effect on plant yield, but the effect of HNT on plant yield was primarily related to a reduction in biomass allocation to reproduction organs and the effect of LNT on plant yield was more related to a negative effect on total biomass. Leaf growth was stimulated at HNT and suppressed at LNT. HNT accelerated plants ecophysiological processes, including photosynthesis and dark respiration, while LNT slowed these processes. Overall, the results showed that the effects of night temperature on plant physiology and growth varied between HNT and LNT, among the response variables and PFTs, and depended on the magnitude of temperature change and experimental design. These findings suggest complexities and challenges in seeking general patterns of terrestrial plant growth in HNT and LNT. The PFT specific responses of plants are critical for

  16. Plant Physiological, Morphological and Yield-Related Responses to Night Temperature Changes across Different Species and Plant Functional Types

    PubMed Central

    Jing, Panpan; Wang, Dan; Zhu, Chunwu; Chen, Jiquan

    2016-01-01

    Land surface temperature over the past decades has shown a faster warming trend during the night than during the day. Extremely low night temperatures have occurred frequently due to the influence of land-sea thermal difference, topography and climate change. This asymmetric night temperature change is expected to affect plant ecophysiology and growth, as the plant carbon consumption processes could be affected more than the assimilation processes because photosynthesis in most plants occurs during the daytime whereas plant respiration occurs throughout the day. The effects of high night temperature (HNT) and low night temperature (LNT) on plant ecophysiological and growing processes and how the effects vary among different plant functional types (PFTs) have not been analyzed extensively. In this meta-analysis, we examined the effect of HNT and LNT on plant physiology and growth across different PFTs and experimental settings. Plant species were grouped according to their photosynthetic pathways (C3, C4, and CAM), growth forms (herbaceous, woody), and economic purposes (crop, non-crop). We found that HNT and LNT both had a negative effect on plant yield, but the effect of HNT on plant yield was primarily related to a reduction in biomass allocation to reproduction organs and the effect of LNT on plant yield was more related to a negative effect on total biomass. Leaf growth was stimulated at HNT and suppressed at LNT. HNT accelerated plants ecophysiological processes, including photosynthesis and dark respiration, while LNT slowed these processes. Overall, the results showed that the effects of night temperature on plant physiology and growth varied between HNT and LNT, among the response variables and PFTs, and depended on the magnitude of temperature change and experimental design. These findings suggest complexities and challenges in seeking general patterns of terrestrial plant growth in HNT and LNT. The PFT specific responses of plants are critical for

  17. Preliminary results of Physiological plant growth modelling for human life support in space

    NASA Astrophysics Data System (ADS)

    Sasidharan L, Swathy; Dussap, Claude-Gilles; Hezard, Pauline

    2012-07-01

    Human life support is fundamental and crucial in any kind of space explorations. MELiSSA project of European Space Agency aims at developing a closed, artificial ecological life support system involving human, plants and micro organisms. Consuming carbon dioxide and water from the life support system, plants grow in one of the chambers and convert it into food and oxygen along with potable water. The environmental conditions, nutrient availability and its consumption of plants should be studied and necessarily modeled to predict the amount of food, oxygen and water with respect to the environmental changes and limitations. The reliability of a completely closed system mainly depends on the control laws and strategies used. An efficient control can occur, only if the system to control is itself well known, described and ideally if the responses of the system to environmental changes are predictable. In this aspect, the general structure of plant growth model has been designed together with physiological modelling.The physiological model consists of metabolic models of leaves, stem and roots, of which concern specific metabolisms of the associated plant parts. On the basis of the carbon source transport (eg. sucrose) through stem, the metabolic models (leaf and root) can be interconnected to each other and finally coupled to obtain the entire plant model. For the first step, leaf metabolic model network was built using stoichiometric, mass and energy balanced metabolic equations under steady state approach considering all necessary plant pathways for growth and maintenance of leaves. As the experimental data for lettuce plants grown in closed and controlled environmental chambers were available, the leaf metabolic model has been established for lettuce leaves. The constructed metabolic network is analyzed using known stoichiometric metabolic technique called metabolic flux analysis (MFA). Though, the leaf metabolic model alone is not sufficient to achieve the

  18. Physiological and genomic basis of mechanical-functional trade-off in plant vasculature

    PubMed Central

    Sengupta, Sonali; Majumder, Arun Lahiri

    2014-01-01

    Some areas in plant abiotic stress research are not frequently addressed by genomic and molecular tools. One such area is the cross reaction of gravitational force with upward capillary pull of water and the mechanical-functional trade-off in plant vasculature. Although frost, drought and flooding stress greatly impact these physiological processes and consequently plant performance, the genomic and molecular basis of such trade-off is only sporadically addressed and so is its adaptive value. Embolism resistance is an important multiple stress- opposition trait and do offer scopes for critical insight to unravel and modify the input of living cells in the process and their biotechnological intervention may be of great importance. Vascular plants employ different physiological strategies to cope with embolism and variation is observed across the kingdom. The genomic resources in this area have started to emerge and open up possibilities of synthesis, validation and utilization of the new knowledge-base. This review article assesses the research till date on this issue and discusses new possibilities for bridging physiology and genomics of a plant, and foresees its implementation in crop science. PMID:24904619

  19. Detecting plant metabolic responses induced by ground shock using hyperspectral remote sensing and physiological contact measurements

    SciTech Connect

    Pickles, W.L.; Cater, G.A.

    1996-12-03

    A series of field experiments were done to determine if ground shock could have induced physiological responses in plants and if the level of the response could be observed. The observation techniques were remote sensing techniques and direct contact physiological measurements developed by Carter for detecting pre-visual plant stress. The remote sensing technique was similar to that used by Pickles to detect what appeared to be ground shock induced plant stress above the 1993 Non Proliferation Experiment`s underground chemical explosion. The experiment was designed to provide direct plant physiological measurements and remote sensing ratio images and from the same plants at the same time. The simultaneous direct and remote sensing measurements were done to establish a ground truth dataset to compare to the results of the hyperspectral remote sensing measurements. In addition, the experiment was designed to include data on what was thought to be the most probable interfering effect, dehydration. The experimental design included investigating the relative magnitude of the shock induced stress effects compared to dehydration effects.

  20. Molecular and physiological interactions of urea and nitrate uptake in plants

    PubMed Central

    Pinton, Roberto; Tomasi, Nicola; Zanin, Laura

    2016-01-01

    While nitrate acquisition has been extensively studied, less information is available on transport systems of urea. Furthermore, the reciprocal influence of the two sources has not been clarified, so far. In this review, we will discuss recent developments on plant response to urea and nitrate nutrition. Experimental evidence suggests that, when urea and nitrate are available in the external solution, the induction of the uptake systems of each nitrogen (N) source is limited, while plant growth and N utilization is promoted. This physiological behavior might reflect cooperation among acquisition processes, where the activation of different N assimilatory pathways (cytosolic and plastidic pathways), allow a better control on the nutrient uptake. Based on physiological and molecular evidence, plants might increase (N) metabolism promoting a more efficient assimilation of taken-up nitrogen. The beneficial effect of urea and nitrate nutrition might contribute to develop new agronomical approaches to increase the (N) use efficiency in crops. PMID:26338073

  1. Design of Plant Eco-physiology Monitoring System Based on Embedded Technology

    NASA Astrophysics Data System (ADS)

    Li, Yunbing; Wang, Cheng; Qiao, Xiaojun; Liu, Yanfei; Zhang, Xinlu

    A real time system has been developed to collect plant's growth information comprehensively. Plant eco-physiological signals can be collected and analyzed effectively. The system adopted embedded technology: wireless sensors network collect the eco-physiological information. Touch screen and ARM microprocessor make the system work independently without PC. The system is versatile and all parameters can be set by the touch screen. Sensors' intelligent compensation can be realized in this system. Information can be displayed by either graphically or in table mode. The ARM microprocessor provides the interface to connect with the internet, so the system support remote monitoring and controlling. The system has advantages of friendly interface, flexible construction and extension. It's a good tool for plant's management.

  2. Physiological Significance of Low Atmospheric CO 2 for Plant-Climate Interactions

    NASA Astrophysics Data System (ADS)

    Cowling, Sharon A.; Sykes, Martin T.

    1999-09-01

    Methods of palaeoclimate reconstruction from pollen are built upon the assumption that plant-climate interactions remain the same through time or that these interactions are independent of changes in atmospheric CO2. The latter may be problematic because air trapped in polar ice caps indicates that atmospheric CO2 has fluctuated significantly over at least the past 400,000 yr, and likely the last 1.6 million yr. Three other points indicate potential biases for vegetation-based climate proxies. First, C3-plant physiological research shows that the processes that determine growth optima in plants (photosynthesis, mitochondrial respiration, photorespiration) are all highly CO2-dependent, and thus were likely affected by the lower CO2 levels of the last glacial maximum. Second, the ratio of carbon assimilation per unit transpiration (called water-use efficiency) is sensitive to changes in atmospheric CO2 through effects on stomatal conductance and may have altered C3-plant responses to drought. Third, leaf gas-exchange experiments indicate that the response of plants to carbon-depleting environmental stresses are strengthened under low CO2 relative to today. This paper reviews the scope of research addressing the consequences of low atmospheric CO2 for plant and ecosystem processes and highlights why consideration of the physiological effects of low atmospheric CO2 on plant function is recommended for any future refinements to pollen-based palaeoclimatic reconstructions.

  3. The effect of differential growth rates across plants on spectral predictions of physiological parameters.

    PubMed

    Rapaport, Tal; Hochberg, Uri; Rachmilevitch, Shimon; Karnieli, Arnon

    2014-01-01

    Leaves of various ages and positions in a plant's canopy can present distinct physiological, morphological and anatomical characteristics, leading to complexities in selecting a single leaf for spectral representation of an entire plant. A fortiori, as growth rates between canopies differ, spectral-based comparisons across multiple plants--often based on leaves' position but not age--becomes an even more challenging mission. This study explores the effect of differential growth rates on the reflectance variability between leaves of different canopies, and its implication on physiological predictions made by widely-used spectral indices. Two distinct irrigation treatments were applied for one month, in order to trigger the formation of different growth rates between two groups of grapevines. Throughout the experiment, the plants were physiologically and morphologically monitored, while leaves from every part of their canopies were spectrally and histologically sampled. As the control vines were constantly developing new leaves, the water deficit plants were experiencing growth inhibition, resulting in leaves of different age at similar nodal position across the treatments. This modification of the age-position correlation was characterized by a near infrared reflectance difference between younger and older leaves, which was found to be exponentially correlated (R(2) = 0.98) to the age-dependent area of intercellular air spaces within the spongy parenchyma. Overall, the foliage of the control plant became more spectrally variable, creating complications for intra- and inter-treatment leaf-based comparisons. Of the derived indices, the Structure-Insensitive Pigment Index (SIPI) was found indifferent to the age-position effect, allowing the treatments to be compared at any nodal position, while a Normalized Difference Vegetation Index (NDVI)-based stomatal conductance prediction was substantially affected by differential growth rates. As various biotic and abiotic

  4. The Effect of Differential Growth Rates across Plants on Spectral Predictions of Physiological Parameters

    PubMed Central

    Rapaport, Tal; Hochberg, Uri; Rachmilevitch, Shimon; Karnieli, Arnon

    2014-01-01

    Leaves of various ages and positions in a plant's canopy can present distinct physiological, morphological and anatomical characteristics, leading to complexities in selecting a single leaf for spectral representation of an entire plant. A fortiori, as growth rates between canopies differ, spectral-based comparisons across multiple plants – often based on leaves' position but not age – becomes an even more challenging mission. This study explores the effect of differential growth rates on the reflectance variability between leaves of different canopies, and its implication on physiological predictions made by widely-used spectral indices. Two distinct irrigation treatments were applied for one month, in order to trigger the formation of different growth rates between two groups of grapevines. Throughout the experiment, the plants were physiologically and morphologically monitored, while leaves from every part of their canopies were spectrally and histologically sampled. As the control vines were constantly developing new leaves, the water deficit plants were experiencing growth inhibition, resulting in leaves of different age at similar nodal position across the treatments. This modification of the age-position correlation was characterized by a near infrared reflectance difference between younger and older leaves, which was found to be exponentially correlated (R2 = 0.98) to the age-dependent area of intercellular air spaces within the spongy parenchyma. Overall, the foliage of the control plant became more spectrally variable, creating complications for intra- and inter-treatment leaf-based comparisons. Of the derived indices, the Structure-Insensitive Pigment Index (SIPI) was found indifferent to the age-position effect, allowing the treatments to be compared at any nodal position, while a Normalized Difference Vegetation Index (NDVI)-based stomatal conductance prediction was substantially affected by differential growth rates. As various biotic and

  5. Host physiological condition regulates parasitic plant performance: Arceuthobium vaginatum subsp. cryptopodum on Pinus ponderosa.

    PubMed

    Bickford, Christopher P; Kolb, Thomas E; Geils, Brian W

    2005-12-01

    Much research has focused on effects of plant parasites on host-plant physiology and growth, but little is known about effects of host physiological condition on parasite growth. Using the parasitic dwarf mistletoe Arceuthobium vaginatum subsp. cryptopodum (Viscaceae) and its host Pinus ponderosa, we investigated whether changes in host physiological condition influenced mistletoe shoot development in northern Arizona forests. We conducted two studies in two consecutive years and used forest thinning (i.e., competitive release) to manipulate host physiological condition. We removed dwarf mistletoe shoots in April, before the onset of the growing season, and measured the amount of regrowth in the first season after forest thinning (Study I: n=38 trees; Study II: n=35 trees). Thinning increased tree uptake of water and carbon in both studies, but had no effect on leaf N concentration or delta13C. Mistletoe shoot growth was greater on trees with high uptake of water and carbon in thinned stands than trees with low uptake in unthinned stands. These findings show that increased resource uptake by host trees increases resources to these heterotrophic dwarf mistletoes, and links mistletoe performance to changes in host physiological condition.

  6. Biological consilience of hydrogen sulfide and nitric oxide in plants: Gases of primordial earth linking plant, microbial and animal physiologies.

    PubMed

    Yamasaki, Hideo; Cohen, Michael F

    2016-05-01

    Hydrogen sulfide (H2S) is produced in the mammalian body through the enzymatic activities of cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3MST). A growing number of studies have revealed that biogenic H2S produced in tissues is involved in a variety of physiological responses in mammals including vasorelaxation and neurotransmission. It is now evident that mammals utilize H2S to regulate multiple signaling systems, echoing the research history of the gaseous signaling molecules nitric oxide (NO) and carbon monoxide (CO) that had previously only been recognized for their cytotoxicity. In the human diet, meats (mammals, birds and fishes) and vegetables (plants) containing cysteine and other sulfur compounds are the major dietary sources for endogenous production of H2S. Plants are primary producers in ecosystems on the earth and they synthesize organic sulfur compounds through the activity of sulfur assimilation. Although plant H2S-producing activities have been known for a long time, our knowledge of H2S biology in plant systems has not been updated to the extent of mammalian studies. Here we review recent progress on H2S studies, highlighting plants and bacteria. Scoping the future integration of H2S, NO and O2 biology, we discuss a possible linkage between physiology, ecology and evolutional biology of gas metabolisms that may reflect the historical changes of the Earth's atmospheric composition.

  7. Ecosystem services and plant physiological status during endophyte-assisted phytoremediation of metal contaminated soil.

    PubMed

    Burges, Aritz; Epelde, Lur; Blanco, Fernando; Becerril, José M; Garbisu, Carlos

    2017-04-15

    Mining sites shelter a characteristic biodiversity with large potential for the phytoremediation of metal contaminated soils. Endophytic plant growth-promoting bacteria were isolated from two metal-(hyper)accumulator plant species growing in a metal contaminated mine soil. After characterizing their plant growth-promoting traits, consortia of putative endophytes were used to carry out an endophyte-assisted phytoextraction experiment using Noccaea caerulescens and Rumex acetosa (singly and in combination) under controlled conditions. We evaluated the influence of endophyte-inoculated plants on soil physicochemical and microbial properties, as well as plant physiological parameters and metal concentrations. Data interpretation through the grouping of soil properties within a set of ecosystem services was also carried out. When grown together, we observed a 41 and 16% increase in the growth of N. caerulescens and R. acetosa plants, respectively, as well as higher values of Zn phytoextraction and soil microbial biomass and functional diversity. Inoculation of the consortia of putative endophytes did not lead to higher values of plant metal uptake, but it improved the plants' physiological status, by increasing the content of chlorophylls and carotenoids by up to 28 and 36%, respectively, indicating a reduction in the stress level of plants. Endophyte-inoculation also stimulated soil microbial communities: higher values of acid phosphatase activity (related to the phosphate solubilising traits of the endophytes), bacterial and fungal abundance, and structural diversity. The positive effects of plant growth and endophyte inoculation on soil properties were reflected in an enhancement of some ecosystem services (biodiversity, nutrient cycling, water flow regulation, water purification and contamination control).

  8. Basic versus applied research: Julius Sachs (1832–1897) and the experimental physiology of plants

    PubMed Central

    Kutschera, Ulrich

    2015-01-01

    The German biologist Julius Sachs was the first to introduce controlled, accurate, quantitative experimentation into the botanical sciences, and is regarded as the founder of modern plant physiology. His seminal monograph Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants) was published 150 y ago (1865), when Sachs was employed as a lecturer at the Agricultural Academy in Poppelsdorf/Bonn (now part of the University). This book marks the beginning of a new era of basic and applied plant science. In this contribution, I summarize the achievements of Sachs and outline his lasting legacy. In addition, I show that Sachs was one of the first biologists who integrated bacteria, which he considered to be descendants of fungi, into the botanical sciences and discussed their interaction with land plants (degradation of wood etc.). This “plant-microbe-view” of green organisms was extended and elaborated by the laboratory botanist Wilhelm Pfeffer (1845–1920), so that the term “Sachs-Pfeffer-Principle of Experimental Plant Research” appears to be appropriate to characterize this novel way of performing scientific studies on green, photoautotrophic organisms (embryophytes, algae, cyanobacteria). PMID:26146794

  9. Basic versus applied research: Julius Sachs (1832-1897) and the experimental physiology of plants.

    PubMed

    Kutschera, Ulrich

    2015-01-01

    The German biologist Julius Sachs was the first to introduce controlled, accurate, quantitative experimentation into the botanical sciences, and is regarded as the founder of modern plant physiology. His seminal monograph Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants) was published 150 y ago (1865), when Sachs was employed as a lecturer at the Agricultural Academy in Poppelsdorf/Bonn (now part of the University). This book marks the beginning of a new era of basic and applied plant science. In this contribution, I summarize the achievements of Sachs and outline his lasting legacy. In addition, I show that Sachs was one of the first biologists who integrated bacteria, which he considered to be descendants of fungi, into the botanical sciences and discussed their interaction with land plants (degradation of wood etc.). This "plant-microbe-view" of green organisms was extended and elaborated by the laboratory botanist Wilhelm Pfeffer (1845-1920), so that the term "Sachs-Pfeffer-Principle of Experimental Plant Research" appears to be appropriate to characterize this novel way of performing scientific studies on green, photoautotrophic organisms (embryophytes, algae, cyanobacteria).

  10. Beyond the climate envelope: using trait filtering models to predict biome boundaries from plant physiology.

    NASA Astrophysics Data System (ADS)

    Fisher, R.; Hoffmann, W. A.; Muszala, S.

    2014-12-01

    The introduction of second-generation dynamic vegetation models - which simulate the distribution of light resources between plant types along the vertical canopy profile, and therefore facilitate the representation of plant competition explicitly - is a large increase in the complexity and fidelity with which the terrestrial biosphere is abstracted into Earth System Models. In this new class of model, biome boundaries are predicted as the emergent properties of plant physiology, and are therefore sensitive to the high-dimensional parameterizations of plant functional traits. These new approaches offer the facility to quantitatively test ecophysiological hypotheses of plant distribution at large scales, a field which remains surprisingly under-developed. Here we describe experiments conducted with the Community Land Model Ecosystem Demography component, CLM(ED), in which we reduce the complexity of the problem by testing how individual plant functional trait changes to control the location of biome boundaries between functional types. Specifically, we investigate which physiological trade-offs determine the boundary between frequently burned savanna and forest biomes, and attempt to distinguish how each strategic life-history trade-off (carbon storage, bark investment, re-sprouting strategy) contributes towards the maintenance of sharp geographical gradients between fire adapted and typically inflammable closed canopy ecosystems. This study forms part of the planning for a model-inspired fire manipulation experiment at the cerrado-forest boundary in South-Eastern Brazil, and the results will be used to guide future data-collection and analysis strategies.

  11. Near-UV radiation acts as a beneficial factor for physiological responses in cucumber plants.

    PubMed

    Mitani-Sano, Makiko; Tezuka, Takafumi

    2013-11-05

    Effects of near-UV radiation on the growth and physiological activity of cucumber plants were investigated morphologically, physiologically and biochemically using 3-week-old seedlings grown under polyvinyl chloride films featuring transmission either above 290 nm or above 400 nm in growth chambers. The hypocotyl length and leaf area of cucumber seedlings were reduced but the thickness of leaves was enhanced by near-UV radiation, due to increased upper/lower epidermis thickness, palisade parenchyma thickness and volume of palisade parenchyma cells. Photosynthetic and respiratory activities were also promoted by near-UV radiation, associated with general enhancement of physiological/biochemical responses. Particularly, metabolic activities in the photosynthetic system of chloroplasts and the respiratory system of mitochondria were analyzed under the conditions of visible light with and without near-UV radiation. For example, the activities of NAD(P)-dependent enzymes such as glyceraldehyde-3-phosphate dehydrogenase (G3PDH) in chloroplasts and isocitrate dehydrogenase (ICDH) in mitochondria were elevated, along with levels of pyridine nucleotides (nicotinamide coenzymes) [NAD(H) and NADP(H)] and activity of NAD kinase (NADP forming enzyme). Taken together, these data suggest that promotion of cucumber plant growth by near-UV radiation involves activation of carbon and nitrogen metabolism in plants. The findings of this research showed that near-UV radiation reaching the Earth's surface is a beneficial factor for plant growth.

  12. Plant neighbor identity influences plant biochemistry and physiology related to defense

    PubMed Central

    2010-01-01

    Background Chemical and biological processes dictate an individual organism's ability to recognize and respond to other organisms. A small but growing body of evidence suggests that plants may be capable of recognizing and responding to neighboring plants in a species specific fashion. Here we tested whether or not individuals of the invasive exotic weed, Centaurea maculosa, would modulate their defensive strategy in response to different plant neighbors. Results In the greenhouse, C. maculosa individuals were paired with either conspecific (C. maculosa) or heterospecific (Festuca idahoensis) plant neighbors and elicited with the plant defense signaling molecule methyl jasmonate to mimic insect herbivory. We found that elicited C. maculosa plants grown with conspecific neighbors exhibited increased levels of total phenolics, whereas those grown with heterospecific neighbors allocated more resources towards growth. To further investigate these results in the field, we conducted a metabolomics analysis to explore chemical differences between individuals of C. maculosa growing in naturally occurring conspecific and heterospecific field stands. Similar to the greenhouse results, C. maculosa individuals accumulated higher levels of defense-related secondary metabolites and lower levels of primary metabolites when growing in conspecific versus heterospecific field stands. Leaf herbivory was similar in both stand types; however, a separate field study positively correlated specialist herbivore load with higher densities of C. maculosa conspecifics. Conclusions Our results suggest that an individual C. maculosa plant can change its defensive strategy based on the identity of its plant neighbors. This is likely to have important consequences for individual and community success. PMID:20565801

  13. The role of plant physiology in hydrology: looking backwards and forwards

    NASA Astrophysics Data System (ADS)

    Roberts, J.

    2007-01-01

    The implementation of plant physiological studies at the Institute of Hydrology focussed both on examining and understanding the physiological controls of transpiration as well as evaluating the value of using physiological methods to measure transpiration. Transpiration measurement by physiological methods would be particularly valuable where this could not be achieved by micrometeorological and soil physics methods. The principal physiological measurements used were determinations of leaf stomatal conductance and leaf water relations to monitor plant water stress. In this paper the value of these approaches is illustrated by describing a few case studies in which plant physiological insight, provided both as new measurements and existing knowledge, would aid in the interpretation of the hydrological behaviour of important vegetation. Woody vegetation figured largely in these studies, conducted in the UK and overseas. Each of these case studies is formulated as a quest to answer a particular question. A collaborative comparison of conifer forest transpiration in Thetford forest using micrometeorological and soil physics techniques exhibited a substantially larger (~1 mm day-1) estimate from the micrometeorological approach. So the question - Why is there a disagreement in the estimates of forest transpiration made using micrometeorological and soil physics approaches? A range of physiological studies followed that suggested that there was no one simple answer but that the larger estimate from the micrometeorology technique might include contributions of water taken up by deep roots, from shallow-rooted vegetation and possibly also from water previously stored in trees. These sources of water were probably not included in the soil physics estimate of transpiration. The annual transpiration from woodlands in NW Europe shows a low magnitude and notable similarity between different sites raising the question - Why is transpiration from European forests low and

  14. Plants and men in space - A new field in plant physiology

    NASA Technical Reports Server (NTRS)

    Andre, M.; Macelroy, R. D.

    1990-01-01

    Results are presented on a comparison of nutritional values of and human psychological responses to algae and of higher plants considered for growth as food on long-term missions in space, together with the technological complexities of growing these plants. The comparison shows the advantages of higher plants, with results suggesting that a high level of material recycling can be obtained. It is noted that the issue of space gravity may be not a major problem for plants because of the possibility that phototropism can provide an alternative sense of direction. Problems of waste recycling can be solved in association with plant cultivation, and a high degree of autonomy of food production can be obtained.

  15. Physiological Implications of Hydrogen Sulfide in Plants: Pleasant Exploration behind Its Unpleasant Odour

    PubMed Central

    Jin, Zhuping

    2015-01-01

    Recently, overwhelming evidence has proven that hydrogen sulfide (H2S), which was identified as a gasotransmitter in animals, plays important roles in diverse physiological processes in plants as well. With the discovery and systematic classification of the enzymes producing H2S in vivo, a better understanding of the mechanisms by which H2S influences plant responses to various stimuli was reached. There are many functions of H2S, including the modulation of defense responses and plant growth and development, as well as the regulation of senescence and maturation. Additionally, mounting evidence indicates that H2S signaling interacts with plant hormones, hydrogen peroxide, nitric oxide, carbon monoxide, and other molecules in signaling pathways. PMID:26078806

  16. Plant chromium uptake and transport, physiological effects and recent advances in molecular investigations.

    PubMed

    Gomes, Maria Angélica da Conceição; Hauser-Davis, Rachel Ann; Suzuki, Marina Satika; Vitória, Angela Pierre

    2017-06-01

    Increasingly, anthropogenic perturbations of the biosphere manifest in a broad array of global phenomena, causing widespread contamination of most ecosystems, with high dispersion rates of many contaminants throughout different environmental compartments, including metals. Chromium (Cr) contamination in particular, is, increasingly, posing a serious threat to the environment, emerging as a major health hazard to the biota. However, although the molecular and physiological mechanisms of plant responses to many heavy metals, especially lead (Pb) and cadmium (Cd), have been focused upon in recent years, chromium has attracted significantly less attention. In this context, this review discusses aspects of Cr uptake and transport, some physiological and biochemical effects of Cr exposure in plants, and molecular defense mechanisms against this metal. Recent advances in determining these responses, in fields of knowledge such as genomics, proteomics and metallomics, are discussed herein.

  17. [Plant physiological and molecular biological mechanism in response to aluminium toxicity].

    PubMed

    Liu, Qiang; Zheng, Shaojian; Lin, Xianyong

    2004-09-01

    Aluminium toxicity is the major factor limiting crop growth on acid soils, which greatly affects the crop productivity on about 40% cultivated soils of the world and 21% of China. In the past decades, a lot of researches on aluminium toxicity and resistant mechanisms have been doing, and great progress was achieved. This paper dealt with the genetic differences in aluminium tolerance among plants, screening and selecting methods and technologies for identifying aluminium resistance in plants, and physiological and molecular mechanism resistance to aluminium toxicity. Some aspects needed to be further studied were also briefly discussed.

  18. Emerging technologies for non-invasive quantification of physiological oxygen transport in plants.

    PubMed

    Chaturvedi, P; Taguchi, M; Burrs, S L; Hauser, B A; Salim, W W A W; Claussen, J C; McLamore, E S

    2013-09-01

    Oxygen plays a critical role in plant metabolism, stress response/signaling, and adaptation to environmental changes (Lambers and Colmer, Plant Soil 274:7-15, 2005; Pitzschke et al., Antioxid Redox Signal 8:1757-1764, 2006; Van Breusegem et al., Plant Sci 161:405-414, 2001). Reactive oxygen species (ROS), by-products of various metabolic pathways in which oxygen is a key molecule, are produced during adaptation responses to environmental stress. While much is known about plant adaptation to stress (e.g., detoxifying enzymes, antioxidant production), the link between ROS metabolism, O2 transport, and stress response mechanisms is unknown. Thus, non-invasive technologies for measuring O2 are critical for understanding the link between physiological O2 transport and ROS signaling. New non-invasive technologies allow real-time measurement of O2 at the single cell and even organelle levels. This review briefly summarizes currently available (i.e., mainstream) technologies for measuring O2 and then introduces emerging technologies for measuring O2. Advanced techniques that provide the ability to non-invasively (i.e., non-destructively) measure O2 are highlighted. In the near future, these non-invasive sensors will facilitate novel experimentation that will allow plant physiologists to ask new hypothesis-driven research questions aimed at improving our understanding of physiological O2 transport.

  19. Physiological and growth response of rice plants (Oryza sativa L.) to Trichoderma spp. inoculants

    PubMed Central

    2014-01-01

    Trichoderma spp., a known beneficial fungus is reported to have several mechanisms to enhance plant growth. In this study, the effectiveness of seven isolates of Trichoderma spp. to promote growth and increase physiological performance in rice was evaluated experimentally using completely randomized design under greenhouse condition. This study indicated that all the Trichoderma spp. isolates tested were able to increase several rice physiological processes which include net photosynthetic rate, stomatal conductance, transpiration, internal CO2 concentration and water use efficiency. These Trichoderma spp. isolates were also able to enhance rice growth components including plant height, leaf number, tiller number, root length and root fresh weight. Among the Trichoderma spp. isolates, Trichoderma sp. SL2 inoculated rice plants exhibited greater net photosynthetic rate (8.66 μmolCO2 m−2 s−1), internal CO2 concentration (336.97 ppm), water use efficiency (1.15 μmoCO2/mmoH2O), plant height (70.47 cm), tiller number (12), root length (22.5 cm) and root fresh weight (15.21 g) compared to the plants treated with other Trichoderma isolates tested. We conclude that beneficial fungi can be used as a potential growth promoting agent in rice cultivation. PMID:24949276

  20. Pollen viability, physiology, and production of maize plants exposed to pyraclostrobin+epoxiconazole.

    PubMed

    Junqueira, Verônica Barbosa; Costa, Alan Carlos; Boff, Tatiana; Müller, Caroline; Mendonça, Maria Andréia Corrêa; Batista, Priscila Ferreira

    2017-04-01

    The use of fungicides in maize has been more frequent due to an increase in the incidence of diseases and also the possible physiological benefits that some of these products may cause. However, some of these products (e.g., strobilurins and triazoles) may interfere with physiological processes and the formation of reproductive organs. Therefore, the effect of these products on plants at different developmental stages needs to be better understood to reduce losses and maximize production. The effect of the fungicide pyraclostrobin+epoxiconazole (P+E) was evaluated at different growth stages in meiosis, pollen grain viability and germination, physiology, and production of maize plants in the absence of disease. An experiment was carried out with the hybrid DKB390 PROII and the application of pyraclostrobin+epoxiconazole at the recommended dose and an untreated control at 3 different timings (S1 - V10; S2 - V14; S3 - R1) with 5 replications. Gas exchange, chlorophyll fluorescence, pollen viability and germination, as well as the hundred-grain weight were evaluated. Anthers were collected from plants of S1 for cytogenetic analysis. The fungicide pyraclostrobin+epoxiconazole reduced the viability of pollen grains (1.4%), but this was not enough to reduce production. Moreover, no differences were observed in any of the other parameters analyzed, suggesting that P+E at the recommended dose and the tested stages does not cause toxic effects.

  1. Physiological and proteomic characterization of salt tolerance in a mangrove plant, Bruguiera gymnorrhiza (L.) Lam.

    PubMed

    Zhu, Zhu; Chen, Juan; Zheng, Hai-Lei

    2012-11-01

    Salinity is a major abiotic stress that is responsible for growth reduction in most higher plants. Bruguiera gymnorrhiza (L.) Lam., a mangrove plant, is a halophyte and is one of the most salt-tolerant plant species. Physiological and proteomic characteristics of B. gymnorrhiza were investigated under three NaCl concentrations (0, 200 and 500 mM) in this study. Maximum seedling growth occurred at 200 mM NaCl. Leaf osmotic potential was more negative as salt levels increased further. Physiological results revealed that inorganic ions (especially Na(+) and Cl(-)) played a key role in osmotic adjustment of B. gymnorrhiza leaves under salinity treatments. Comparative proteomic analysis revealed 23 salt-responsive proteins in B. gymnorrhiza leaves, which were differentially expressed under salt treatment compared with control. Ten protein spots were analyzed by liquid chromatography-tandem mass spectrometry, leading to identification of proteins involved in photosynthesis, antioxidation, protein folding, cell organization and metabolism. Salt-responsive mechanism was different between 200 and 500 mM NaCl-treated plants on the basis of the physiological and proteomic analyses. Salt tolerance under 200 mM NaCl treatment was due to effective osmotic adjustment, accumulation of inorganic ions (especially Na(+) and Cl(-)) as well as increased expression of photosynthesis-related proteins and antioxidant enzymes, which improved the salt tolerance of B. gymnorrhiza, and furthermore promoted plant growth. On the other hand, 500 mM NaCl reduced the growth of B. gymnorrhiza, which appears to have been caused by the accumulation of NaCl (ionic effect) and energy consumption by organic solute synthesis. Moreover, the repressed expression of photosynthesis-related proteins and antioxidant enzymes led to the reduction of growth. Protein folding and degradation-related proteins and cell organization-related protein were up-regulated and played important roles in salt tolerance of B

  2. Resolving the role of plant glutamate dehydrogenase: II. Physiological characterization of plants overexpressing the two enzyme subunits individually or simultaneously.

    PubMed

    Tercé-Laforgue, Thérèse; Bedu, Magali; Dargel-Grafin, Céline; Dubois, Frédéric; Gibon, Yves; Restivo, Francesco M; Hirel, Bertrand

    2013-10-01

    Glutamate dehydrogenase (GDH; EC 1.4.1.2) is able to carry out the deamination of glutamate in higher plants. In order to obtain a better understanding of the physiological function of GDH in leaves, transgenic tobacco (Nicotiana tabacum L.) plants were constructed that overexpress two genes from Nicotiana plumbaginifolia (GDHA and GDHB under the control of the Cauliflower mosiac virus 35S promoter), which encode the α- and β-subunits of GDH individually or simultaneously. In the transgenic plants, the GDH protein accumulated in the mitochondria of mesophyll cells and in the mitochondria of the phloem companion cells (CCs), where the native enzyme is normally expressed. Such a shift in the cellular location of the GDH enzyme induced major changes in carbon and nitrogen metabolite accumulation and a reduction in growth. These changes were mainly characterized by a decrease in the amount of sucrose, starch and glutamine in the leaves, which was accompanied by an increase in the amount of nitrate and Chl. In addition, there was an increase in the content of asparagine and a decrease in proline. Such changes may explain the lower plant biomass determined in the GDH-overexpressing lines. Overexpressing the two genes GDHA and GDHB individually or simultaneously induced a differential accumulation of glutamate and glutamine and a modification of the glutamate to glutamine ratio. The impact of the metabolic changes occurring in the different types of GDH-overexpressing plants is discussed in relation to the possible physiological function of each subunit when present in the form of homohexamers or heterohexamers.

  3. Changes in the Physiological Parameters of SbPIP1-Transformed Wheat Plants under Salt Stress

    PubMed Central

    Yu, G. H.; Zhang, X.; Ma, H. X.

    2015-01-01

    The SbPIP1 gene is a new member of the plasma membrane major intrinsic gene family cloned from the euhalophyte Salicornia bigelovii Torr. In order to understand the physiological responses in plants that are mediated by the SbPIP1 gene, SbPIP1-overexpressing wheat lines and WT plants of the wheat cv. Ningmai 13 were treated with salt stress. Several physiological parameters, such as the proline content, the malondialdehyde (MDA) content, and the content of soluble sugars and proteins, were compared between SbPIP1-transformed lines and WT plants under normal growth or salt stress conditions. The results indicate that overexpression of the SbPIP1 gene can increase the accumulation of the osmolyte proline, decrease the MDA content, and enhance the soluble sugar biosynthesis in the early period but has no influence on the regulation of soluble protein biosynthesis in wheat. The results suggest that SbPIP1 contributes to salt tolerance by facilitating the accumulation of the osmolyte proline, increasing the antioxidant response, and increasing the biosynthesis of soluble sugar in the early period. These results indicate SbPIP1 plays an important role in the salt stress response. Overexpression of SbPIP1 might be used to improve the salt tolerance of important crop plants. PMID:26495278

  4. Isoprene improves photochemical efficiency and enhances heat dissipation in plants at physiological temperatures.

    PubMed

    Pollastri, Susanna; Tsonev, Tsonko; Loreto, Francesco

    2014-04-01

    Isoprene-emitting plants are better protected against thermal and oxidative stresses. Isoprene may strengthen membranes avoiding their denaturation and may quench reactive oxygen and nitrogen species, achieving a similar protective effect. The physiological role of isoprene in unstressed plants, up to now, is not understood. It is shown here, by monitoring the non-photochemical quenching (NPQ) of chlorophyll fluorescence of leaves with chemically or genetically altered isoprene biosynthesis, that chloroplasts of isoprene-emitting leaves dissipate less energy as heat than chloroplasts of non-emitting leaves, when exposed to physiologically high temperatures (28-37 °C) that do not impair the photosynthetic apparatus. The effect was especially remarkable at foliar temperatures between 30 °C and 35 °C, at which isoprene emission is maximized and NPQ is quenched by about 20%. Isoprene may also allow better stability of photosynthetic membranes and a more efficient electron transfer through PSII at physiological temperatures, explaining most of the NPQ reduction and the slightly higher photochemical quenching that was also observed in isoprene-emitting leaves. The possibility that isoprene emission helps in removing thermal energy at the thylakoid level is also put forward, although such an effect was calculated to be minimal. These experiments expand current evidence that isoprene is an important trait against thermal and oxidative stresses and also explains why plants invest resources in isoprene under unstressed conditions. By improving PSII efficiency and reducing the need for heat dissipation in photosynthetic membranes, isoprene emitters are best fitted to physiologically high temperatures and will have an evolutionary advantage when adapting to a warming climate.

  5. Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients

    USGS Publications Warehouse

    Spasojevic, Marko J.; Grace, James B.; Harrison, Susan; Damschen, Ellen Ingman

    2013-01-01

    1. The physiological tolerance hypothesis proposes that plant species richness is highest in warm and/or wet climates because a wider range of functional strategies can persist under such conditions. Functional diversity metrics, combined with statistical modeling, offer new ways to test whether diversity-environment relationships are consistent with this hypothesis. 2. In a classic study by R. H. Whittaker (1960), herb species richness declined from mesic (cool, moist, northerly) slopes to xeric (hot, dry, southerly) slopes. Building on this dataset, we measured four plant functional traits (plant height, specific leaf area, leaf water content and foliar C:N) and used them to calculate three functional diversity metrics (functional richness, evenness, and dispersion). We then used a structural equation model to ask if ‘functional diversity’ (modeled as the joint responses of richness, evenness, and dispersion) could explain the observed relationship of topographic climate gradients to species richness. We then repeated our model examining the functional diversity of each of the four traits individually. 3. Consistent with the physiological tolerance hypothesis, we found that functional diversity was higher in more favorable climatic conditions (mesic slopes), and that multivariate functional diversity mediated the relationship of the topographic climate gradient to plant species richness. We found similar patterns for models focusing on individual trait functional diversity of leaf water content and foliar C:N. 4. Synthesis. Our results provide trait-based support for the physiological tolerance hypothesis, suggesting that benign climates support more species because they allow for a wider range of functional strategies.

  6. Regulation of K+ channel activities in plants: from physiological to molecular aspects.

    PubMed

    Chérel, Isabelle

    2004-02-01

    Plant voltage-gated channels belonging to the Shaker family participate in sustained K+ transport processes at the cell and whole plant levels, such as K+ uptake from the soil solution, long-distance K+ transport in the xylem and phloem, and K+ fluxes in guard cells during stomatal movements. The attention here is focused on the regulation of these transport systems by protein-protein interactions. Clues to the identity of the regulatory mechanisms have been provided by electrophysiological approaches in planta or in heterologous systems, and through analogies with their animal counterparts. It has been shown that, like their animal homologues, plant voltage-gated channels can assemble as homo- or heterotetramers associating polypeptides encoded by different Shaker genes, and that they can bind auxiliary subunits homologous to those identified in mammals. Furthermore, several regulatory processes (involving, for example, protein kinases and phosphatases, G proteins, 14-3-3s, or syntaxins) might be common to plant and animal Shakers. However, the molecular identification of plant channel partners is still at its beginning. This paper reviews current knowledge on plant K+ channel regulation at the physiological and molecular levels, in the light of the corresponding knowledge in animal cells, and discusses perspectives for the deciphering of regulatory networks in the future.

  7. The role of silicon in physiology of the medicinal plant (Lonicera japonica L.) under salt stress

    NASA Astrophysics Data System (ADS)

    Gengmao, Zhao; Shihui, Li; Xing, Sun; Yizhou, Wang; Zipan, Chang

    2015-08-01

    Silicon(Si) is the only element which can enhance the resistance to multiple stresses. However, the role of silicon in medicinal plants under salt stress is not yet understood. This experiment was conducted to study the effects of silicon addition on the growth, osmotic adjustments, photosynthetic characteristics, chloroplast ultrastructure and Chlorogenic acid (CGA) production of Honeysuckle plant (Lonicera japonica L.) under salt-stressed conditions. Salinity exerted an adverse effect on the plant fresh weight and dry weight, whilst 0.5 g L-1 K2SiO3·nH2O addition obviously improved the plant growth. Although Na+ concentration in plant organs was drastically increased with increasing salinity, higher levels of K+/Na+ ratio was obtained after K2SiO3·nH2O addition. Salinity stress induced the destruction of the chloroplast envelope; however, K2SiO3·nH2O addition counteracted the adverse effect by salinity on the structure of the photosynthetic apparatus. K2SiO3·nH2O addition also enhanced the activities of superoxide dismutase and catalase. To sum up, exogenous Si plays a key role in enhancing its resistance to salt stresses in physiological base, thereby improving the growth and CGA production of Honeysuckle plant.

  8. An exceptional role for flowering plant physiology in the expansion of tropical rainforests and biodiversity

    PubMed Central

    Boyce, C. Kevin; Lee, Jung-Eun

    2010-01-01

    Movement of water from soil to atmosphere by plant transpiration can feed precipitation, but is limited by the hydraulic capacities of plants, which have not been uniform through time. The flowering plants that dominate modern vegetation possess transpiration capacities that are dramatically higher than any other plants, living or extinct. Transpiration operates at the level of the leaf, however, and how the impact of this physiological revolution scales up to the landscape and larger environment remains unclear. Here, climate modelling demonstrates that angiosperms help ensure aseasonally high levels of precipitation in the modern tropics. Most strikingly, replacement of angiosperm with non-angiosperm vegetation would result in a hotter, drier and more seasonal Amazon basin, decreasing the overall area of ever-wet rainforest by 80 per cent. Thus, flowering plant ecological dominance has strongly altered climate and the global hydrological cycle. Because tropical biodiversity is closely tied to precipitation and rainforest area, angiosperm climate modification may have promoted diversification of the angiosperms themselves, as well as radiations of diverse vertebrate and invertebrate animal lineages and of epiphytic plants. Their exceptional potential for environmental modification may have contributed to divergent responses to similar climates and global perturbations, like mass extinctions, before and after angiosperm evolution. PMID:20554551

  9. The role of silicon in physiology of the medicinal plant (Lonicera japonica L.) under salt stress.

    PubMed

    Gengmao, Zhao; Shihui, Li; Xing, Sun; Yizhou, Wang; Zipan, Chang

    2015-08-03

    Silicon(Si) is the only element which can enhance the resistance to multiple stresses. However, the role of silicon in medicinal plants under salt stress is not yet understood. This experiment was conducted to study the effects of silicon addition on the growth, osmotic adjustments, photosynthetic characteristics, chloroplast ultrastructure and Chlorogenic acid (CGA) production of Honeysuckle plant (Lonicera japonica L.) under salt-stressed conditions. Salinity exerted an adverse effect on the plant fresh weight and dry weight, whilst 0.5 g L(-1) K2SiO3 · nH2O addition obviously improved the plant growth. Although Na(+) concentration in plant organs was drastically increased with increasing salinity, higher levels of K(+)/Na(+) ratio was obtained after K2SiO3 · nH2O addition. Salinity stress induced the destruction of the chloroplast envelope; however, K2SiO3 · nH2O addition counteracted the adverse effect by salinity on the structure of the photosynthetic apparatus. K2SiO3 · nH2O addition also enhanced the activities of superoxide dismutase and catalase. To sum up, exogenous Si plays a key role in enhancing its resistance to salt stresses in physiological base, thereby improving the growth and CGA production of Honeysuckle plant.

  10. Wired to the roots: impact of root-beneficial microbe interactions on aboveground plant physiology and protection.

    PubMed

    Kumar, Amutha Sampath; Bais, Harsh P

    2012-12-01

    Often, plant-pathogenic microbe interactions are discussed in a host-microbe two-component system, however very little is known about how the diversity of rhizospheric microbes that associate with plants affect host performance against pathogens. There are various studies, which specially direct the importance of induced systemic defense (ISR) response in plants interacting with beneficial rhizobacteria, yet we don't know how rhizobacterial associations modulate plant physiology. In here, we highlight the many dimensions within which plant roots associate with beneficial microbes by regulating aboveground physiology. We review approaches to study the causes and consequences of plant root association with beneficial microbes on aboveground plant-pathogen interactions. The review provides the foundations for future investigations into the impact of the root beneficial microbial associations on plant performance and innate defense responses.

  11. Physiological and biochemical characterization of Trichoderma harzianum, a biological control agent against soilborne fungal plant pathogens.

    PubMed Central

    Grondona, I; Hermosa, R; Tejada, M; Gomis, M D; Mateos, P F; Bridge, P D; Monte, E; Garcia-Acha, I

    1997-01-01

    Monoconidial cultures of 15 isolates of Trichoderma harzianum were characterized on the basis of 82 morphological, physiological, and biochemical features and 99 isoenzyme bands from seven enzyme systems. The results were subjected to numerical analysis which revealed four distinct groups. Representative sequences of the internal transcribed spacer 1 (ITS 1)-ITS 2 region in the ribosomal DNA gene cluster were compared between groups confirming this distribution. The utility of the groupings generated from the morphological, physiological, and biochemical data was assessed by including an additional environmental isolate in the electrophoretic analysis. The in vitro antibiotic activity of the T. harzianum isolates was assayed against 10 isolates of five different soilborne fungal plant pathogens: Aphanomyces cochlioides, Rhizoctonia solani, Phoma betae, Acremonium cucurbitacearum, and Fusarium oxysporum f. sp. radicis lycopersici. Similarities between levels and specificities of biological activity and the numerical characterization groupings are both discussed in relation to antagonist-specific populations in known and potential biocontrol species. PMID:9251205

  12. Physiological relevance of plant 2-Cys peroxiredoxin overoxidation level and oligomerization status.

    PubMed

    Cerveau, Delphine; Ouahrani, Djelloul; Marok, Mohamed Amine; Blanchard, Laurence; Rey, Pascal

    2016-01-01

    Peroxiredoxins are ubiquitous thioredoxin-dependent peroxidases presumed to display, upon environmental constraints, a chaperone function resulting from a redox-dependent conformational switch. In this work, using biochemical and genetic approaches, we aimed to unravel the factors regulating the redox status and the conformation of the plastidial 2-Cys peroxiredoxin (2-Cys PRX) in plants. In Arabidopsis, we show that in optimal growth conditions, the overoxidation level mainly depends on the availability of thioredoxin-related electron donors, but not on sulfiredoxin, the enzyme reducing the 2-Cys PRX overoxidized form. We also observed that upon various physiological temperature, osmotic and light stress conditions, the overoxidation level and oligomerization status of 2-Cys PRX can moderately vary depending on the constraint type. Further, no major change was noticed regarding protein conformation in water-stressed Arabidopsis, barley and potato plants, whereas species-dependent up- and down-variations in overoxidation were observed. In contrast, both 2-Cys PRX overoxidation and oligomerization were strongly induced during a severe oxidative stress generated by methyl viologen. From these data, revealing that the oligomerization status of plant 2-Cys PRX does not exhibit important variation and is not tightly linked to the protein redox status upon physiologically relevant environmental constraints, the possible in planta functions of 2-Cys PRX are discussed.

  13. Mechanism of physiological effects of titanium leaf sprays on plants grown on soil.

    PubMed

    Kuzel, Stanislav; Hruby, Martin; Cígler, Petr; Tlustos, Pavel; Van, Phu Nguyen

    2003-02-01

    Titanium (Ti) has significant biological effects on plants, being beneficial at low and toxic at higher concentrations. From results of our hydroponical experiment with oats, we have recently proposed that the effect called hormesis is the mechanism of Ti action in plants. Here, we present the experiment with oats (Avena sativa L. cv. Zlat'ák) grown on soil where Ti was applied using leaf sprays. Two different soils, three different concentrations of Ti(IV) citrate spray solution (0, 20, and 50 mg Ti/kg), and three different Mg concentrations in each soil were tested. Some physiological parameters (dry and raw weights, top heights, chlorophyll content) and element contents (Mg, Fe, Zn, Mn) were determined. Ti showed considerable effects on all physiological parameters and the element's contents were determined. Differences between the two different soil types used was only in the strength of the effect of Ti; the trends remained unchanged. Generally, the effect of Ti is considerably weaker if Ti is applied on leaves than if being added to the nutrient solution. Thus, we confirm here that the action of Ti on plants could be explained by the hormesis effect.

  14. A comparison of physiological indicators of sublethal cadmium stress in wetland plants

    USGS Publications Warehouse

    Mendelssohn, I.A.; McKee, K.L.; Kong, T.

    2001-01-01

    Physiological indices, including photosynthesis, chlorophyll fluorescence, adenylate energy charge (AEC) ratio, and leaf reflectance, were determined for Typha domingensis and Spartina alterniflora in response to increasing concentrations of Cd and compared with the growth responses of these species. Leaf expansion, the live/total ratio of plant aboveground biomass, and the aboveground regrowth rate after the initial harvests were significantly reduced with increasing Cd concentration in the growth medium. Of the four physiological responses measured, only photosynthesis and AEC responded to the Cd treatment before damage was visually apparent. Also, these indices were significantly correlated with leaf expansion rate and live/total ratio in most instances. Except at the end of the experiment, when the most stressed plants began to die, the Fv/Fm ratio was not significantly affected by the Cd treatment. The leaf spectral reflectance parameters showed no significant change during the entire treatment period. The significant correlation between the stress indicators and plant growth supported the findings that photosynthesis and AEC were the most responsive of the indicators tested, however, further research investigating other chlorophyll fluorescence and leaf reflectance parameters may demonstrate as well the value of these indicators in quantifying sublethal stress. ?? 2001 Elsevier Science B.V. All rights reserved.

  15. Non-linear effects of drought under shade: reconciling physiological and ecological models in plant communities.

    PubMed

    Holmgren, Milena; Gómez-Aparicio, Lorena; Quero, José Luis; Valladares, Fernando

    2012-06-01

    The combined effects of shade and drought on plant performance and the implications for species interactions are highly debated in plant ecology. Empirical evidence for positive and negative effects of shade on the performance of plants under dry conditions supports two contrasting theoretical models about the role of shade under dry conditions: the trade-off and the facilitation hypotheses. We performed a meta-analysis of field and greenhouse studies evaluating the effects of drought at two or more irradiance levels on nine response variables describing plant physiological condition, growth, and survival. We explored differences in plant response across plant functional types, ecosystem types and methodological approaches. The data were best fit using quadratic models indicating a humped-back shape response to drought along an irradiance gradient for survival, whole plant biomass, maximum photosynthetic capacity, stomatal conductance and maximal photochemical efficiency. Drought effects were ameliorated at intermediate irradiance, becoming more severe at higher or lower light levels. This general pattern was maintained when controlling for potential variations in the strength of the drought treatment among light levels. Our quantitative meta-analysis indicates that dense shade ameliorates drought especially among drought-intolerant and shade-tolerant species. Wet tropical species showed larger negative effects of drought with increasing irradiance than semiarid and cold temperate species. Non-linear responses to irradiance were stronger under field conditions than under controlled greenhouse conditions. Non-linear responses to drought along the irradiance gradient reconciliate opposing views in plant ecology, indicating that facilitation is more likely within certain range of environmental conditions, fading under deep shade, especially for drought-tolerant species.

  16. Root growth, mycorrhization and physiological effects of plants growing on oil tailing sands

    NASA Astrophysics Data System (ADS)

    Boldt-Burisch, Katja M.; Naeth, Anne M.; Schneider, Bernd Uwe; Hüttl, Reinhard F.

    2015-04-01

    Surface mining creates large, intense disturbances of soils and produces large volumes of by-products and waste materials. After mining processes these materials often provide the basis for land reclamation and ecosystem restoration. In the present study, tailing sands (TS) and processed mature fine tailings (pMFT) from Fort McMurray (Alberta, Canada) were used. They represent challenging material for ecosystem rebuilding because of very low nutrient contents of TS and oil residuals, high density of MFT material. In this context, little is known about the interactions of pure TS, respectively mixtures of TS and MFT and root growth, mycorrhization and plant physiological effects. Four herbaceous plant species (Elymus trachycaulus, Koeleria macrantha, Deschampsia cespitosa, Lotus corniculatus) were chosen to investigate root development, chlorophyll fluorescence and mycorrhization intensity with and without application of Glomus mosseae (arbuscular mycorrhizae) on mainly tailing sands. Surprisingly both, plants growing on pure TS and plants growing on TS with additional AM-application showed mycorrhization of roots. In general, the mycorrhization intensity was lower for plants growing on pure tailings sands, but it is an interesting fact that there is a potential for mycorrhization available in tailing sands. The mycorrhizal intensity strongly increased with application of G. mosseae for K. macrantha and L. corniculatus and even more for E. trachycaulus. For D. cespitosa similar high mycorrhiza infection frequency was found for both variants, with and without AM-application. By the application of G. mosseae, root growth of E. trachycaulus and K. macrantha was significantly positively influenced. Analysis of leaf chlorophyll fluorescence showed no significant differences for E. trachycaulus but significant positive influence of mycorrhizal application on the physiological status of L. corniculatus. However, this effect could not be detected when TS was mixed with MFT

  17. Mycorrhizal association between the desert truffle Terfezia boudieri and Helianthemum sessiliflorum alters plant physiology and fitness to arid conditions.

    PubMed

    Turgeman, Tidhar; Asher, Jiftach Ben; Roth-Bejerano, Nurit; Kagan-Zur, Varda; Kapulnik, Yoram; Sitrit, Yaron

    2011-10-01

    The host plant Helianthemum sessiliflorum was inoculated with the mycorrhizal desert truffle Terfezia boudieri Chatin, and the subsequent effects of the ectomycorrhizal relationship on host physiology were determined. Diurnal measurements revealed that mycorrhizal (M) plants had higher rates of photosynthesis (35%), transpiration (18%), and night respiration (49%) than non-mycorrhizal (NM) plants. Consequently, M plants exhibited higher biomass accumulation, higher shoot-to-root ratios, and improved water use efficiency compared to NM plants. Total chlorophyll content was higher in M plants, and the ratio between chlorophyll a to chlorophyll b was altered in M plants. The increase in chlorophyll b content was significantly higher than the increase in chlorophyll a content (2.58- and 1.52-fold, respectively) compared to control. Calculation of the photosynthetic activation energy indicated lower energy requirements for CO(2) assimilation in M plants than in NM plants (48.62 and 61.56 kJ mol(-1), respectively). Continuous measurements of CO(2) exchange and transpiration in M plants versus NM plants provided a complete picture of the daily physiological differences brought on by the ectomycorrhizal relationships. The enhanced competence of M plants to withstand the harsh environmental conditions of the desert is discussed in view of the mycorrhizal-derived alterations in host physiology.

  18. Beyond cellular detoxification: a plethora of physiological roles for MDR transporter homologs in plants

    PubMed Central

    Remy, Estelle; Duque, Paula

    2014-01-01

    Higher plants possess a multitude of Multiple Drug Resistance (MDR) transporter homologs that group into three distinct and ubiquitous families—the ATP-Binding Cassette (ABC) superfamily, the Major Facilitator Superfamily (MFS), and the Multidrug And Toxic compound Extrusion (MATE) family. As in other organisms, such as fungi, mammals, and bacteria, MDR transporters make a primary contribution to cellular detoxification processes in plants, mainly through the extrusion of toxic compounds from the cell or their sequestration in the central vacuole. This review aims at summarizing the currently available information on the in vivo roles of MDR transporters in plant systems. Taken together, these data clearly indicate that the biological functions of ABC, MFS, and MATE carriers are not restricted to xenobiotic and metal detoxification. Importantly, the activity of plant MDR transporters also mediates biotic stress resistance and is instrumental in numerous physiological processes essential for optimal plant growth and development, including the regulation of ion homeostasis and polar transport of the phytohormone auxin. PMID:24910617

  19. Effects of foliage plants on human physiological and psychological responses at different temperatures

    NASA Astrophysics Data System (ADS)

    Jumeno, Desto; Matsumoto, Hiroshi

    2015-02-01

    Escalation of task demands and time pressures tends to make a worker run into work stress, which leads to mental fatigue and depression. The mental fatigue can be reduced when attention capacity is restored. Nature can serve as a source of fascination which can restore the attention capacity. People bring plants indoors so they can experience nature in their workplace. The stress and fatigue are also affected by air temperatures. The increase or decrease of temperatures from the comfort zone may induce the stress and fatigue. The objective of this study is to investigate the intervention of using foliage plants placed inside a building at different air temperature levels. The effects of foliage plants on human stress and fatigue were measured by human physiological responses such as heart rate, amylase level, electroencephalography (EEG), and the secondary task-reaction time. Several different tasks, namely typing, math and logical sequences are included in the investigation of these studies. Fifteen subjects, with the age ranged from 22 to 38 years old have participated in the study using within subject design. From the study, it is revealed that the presence of foliage plants at several temperatures have different effects on meditation, secondary task reaction time and typing accuracy. This study also revealed that the presence of plants on several types of tasks has different effects of attention which are useful for increasing work performance.

  20. Tomato Plant Proteins Actively Responding to Fungal Applications and Their Role in Cell Physiology

    PubMed Central

    Bashir, Zoobia; Shafique, Sobiya; Ahmad, Aqeel; Shafique, Shazia; Yasin, Nasim A.; Ashraf, Yaseen; Ibrahim, Asma; Akram, Waheed; Noreen, Sibgha

    2016-01-01

    The pattern of protein induction in tomato plants has been investigated after the applications of pathogenic and non-pathogenic fungal species. Moreover, particular roles of the most active protein against biological applications were also determined using chromatographic techniques. Alternaria alternata and Penicillium oxalicum were applied as a pathogenic and non-pathogenic fungal species, respectively. Protein profile analysis revealed that a five protein species (i.e., protein 1, 6, 10, 12, and 13) possessed completely coupled interaction with non-pathogenic inducer application (P. oxalicum). However, three protein species (i.e., 10, 12, and 14) recorded a strong positive interaction with both fungal species. Protein 14 exhibited the maximum interaction with fungal applications, and its role in plant metabolism was studied after its identification as protein Q9M1W6. It was determined that protein Q1M1W6 was involved in guaiacyl lignin biosynthesis, and its inhibition increased the coumarin contents in tomato plants. Moreover, it was also observed that the protein Q9M1W6 takes significant part in the biosynthesis of jasmonic acid and Indole acetic acid contents, which are defense and growth factors of tomato plants. The study will help investigators to design fundamental rules of plant proteins affecting cell physiology under the influence of external fungal applications. PMID:27445848

  1. Effect of excess iron and copper on physiology of aquatic plant Spirodela polyrrhiza (L.) Schleid.

    PubMed

    Xing, Wei; Huang, Wenmin; Liu, Guihua

    2010-04-01

    To elucidate effect of chemical reagents addition on growth of aquatic plants in restoration of aquatic ecosystem, Spirodela polyrrhiza (L.) Schleid was used to evaluate its physiological responses to excess iron (Fe(3+)) and copper (Cu(2+)) in the study. Results showed that accumulation of iron and copper both reached maximum at 100 mg L(-1) iron or copper after 24 h short-term stress, but excess iron and copper caused plants necrosis or death and colonies disintegration as well as roots abscission at excess metal concentrations except for 1 mg L(-1) iron. Significant differences in chlorophyll fluorescence (Fv/Fm) were observed at 1-100 mg L(-1) iron or copper. The synthesis of chlorophyll and protein as well as carbohydrate and the uptake of phosphate and nitrogen were inhibited seriously by excess iron and copper. Proline content decreased with increasing iron or copper concentration, however, MDA content increased with increasing iron or copper concentration.

  2. The plant Ca2+ -ATPase repertoire: biochemical features and physiological functions.

    PubMed

    Bonza, M C; De Michelis, M I

    2011-05-01

    Ca(2+)-ATPases are P-type ATPases that use the energy of ATP hydrolysis to pump Ca(2+) from the cytoplasm into intracellular compartments or into the apoplast. Plant cells possess two types of Ca(2+) -pumping ATPase, named ECAs (for ER-type Ca(2+)-ATPase) and ACAs (for auto-inhibited Ca(2+)-ATPase). Each type comprises different isoforms, localised on different membranes. Here, we summarise available knowledge of the biochemical characteristics and the physiological role of plant Ca(2+)-ATPases, greatly improved after gene identification, which allows both biochemical analysis of single isoforms through heterologous expression in yeast and expression profiling and phenotypic analysis of single isoform knock-out mutants.

  3. Quantifying succulence: a rapid, physiologically meaningful metric of plant water storage.

    PubMed

    Ogburn, R Matthew; Edwards, Erika J

    2012-09-01

    Quantification of succulence should ideally convey information about physiological function and yet also be straightforward to measure. While important aspects of succulence and its physiological consequences may be quantified using parameters derived from pressure-volume (P-V) curves, this technique applied to succulent tissues is difficult, time consuming and generally not suitable for large comparative datasets. We performed P-V curves on leaves of 25 taxa from across Caryophyllales and compared the results with direct measures of saturated water content (SWC(meas) ), the ratio of water mass at full saturation to tissue dry mass, for the same taxa. SWC(meas) was significantly related to relative capacitance, the most physiologically relevant parameter describing tissue succulence. We developed a linear model describing SWC(meas) as a function of relative capacitance and leaf volume, which is also supported when accounting for the phylogenetic relationships among taxa. These results indicate that SWC(meas) is a suitable proxy for tissue succulence, and that both cellular properties and variation in gross morphology contribute towards a plant's relative water storage capacity. Quantifying SWC(meas) across many taxa showing variation in tissue succulence will provide a new avenue for exploring the evolutionary dynamics of this important ecological adaptation.

  4. PPDB - A tool for investigation of plants physiology based on gene ontology.

    PubMed

    Sharma, Ajay Shiv; Gupta, Hari Om; Prasad, Rajendra

    2014-09-02

    Representing the way forward, from functional genomics and its ontology to functional understanding and physiological model, in a computationally tractable fashion is one of the ongoing challenges faced by computational biology. To tackle the standpoint, we herein feature the applications of contemporary database management to the development of PPDB, a searching and browsing tool for the Plants Physiology Database that is based upon the mining of a large amount of gene ontology data currently available. The working principles and search options associated with the PPDB are publicly available and freely accessible on-line ( http://www.iitr.ernet.in/ajayshiv/ ) through a user friendly environment generated by means of Drupal-6.24. By knowing that genes are expressed in temporally and spatially characteristic patterns and that their functionally distinct products often reside in specific cellular compartments and may be part of one or more multi-component complexes, this sort of work is intended to be relevant for investigating the functional relationships of gene products at a system level and, thus, helps us approach to the full physiology.

  5. PPDB: A Tool for Investigation of Plants Physiology Based on Gene Ontology.

    PubMed

    Sharma, Ajay Shiv; Gupta, Hari Om; Prasad, Rajendra

    2015-09-01

    Representing the way forward, from functional genomics and its ontology to functional understanding and physiological model, in a computationally tractable fashion is one of the ongoing challenges faced by computational biology. To tackle the standpoint, we herein feature the applications of contemporary database management to the development of PPDB, a searching and browsing tool for the Plants Physiology Database that is based upon the mining of a large amount of gene ontology data currently available. The working principles and search options associated with the PPDB are publicly available and freely accessible online ( http://www.iitr.ac.in/ajayshiv/ ) through a user-friendly environment generated by means of Drupal-6.24. By knowing that genes are expressed in temporally and spatially characteristic patterns and that their functionally distinct products often reside in specific cellular compartments and may be part of one or more multicomponent complexes, this sort of work is intended to be relevant for investigating the functional relationships of gene products at a system level and, thus, helps us approach to the full physiology.

  6. Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.

    PubMed

    Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

    2015-01-01

    Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P

  7. Physiological, biochemical and molecular responses of the potato (Solanum tuberosum L.) plant to moderately elevated temperature.

    PubMed

    Hancock, Robert D; Morris, Wayne L; Ducreux, Laurence J M; Morris, Jenny A; Usman, Muhammad; Verrall, Susan R; Fuller, John; Simpson, Craig G; Zhang, Runxuan; Hedley, Pete E; Taylor, Mark A

    2014-02-01

    Although significant work has been undertaken regarding the response of model and crop plants to heat shock during the acclimatory phase, few studies have examined the steady-state response to the mild heat stress encountered in temperate agriculture. In the present work, we therefore exposed tuberizing potato plants to mildly elevated temperatures (30/20 °C, day/night) for up to 5 weeks and compared tuber yield, physiological and biochemical responses, and leaf and tuber metabolomes and transcriptomes with plants grown under optimal conditions (22/16 °C). Growth at elevated temperature reduced tuber yield despite an increase in net foliar photosynthesis. This was associated with major shifts in leaf and tuber metabolite profiles, a significant decrease in leaf glutathione redox state and decreased starch synthesis in tubers. Furthermore, growth at elevated temperature had a profound impact on leaf and tuber transcript expression with large numbers of transcripts displaying a rhythmic oscillation at the higher growth temperature. RT-PCR revealed perturbation in the expression of circadian clock transcripts including StSP6A, previously identified as a tuberization signal. Our data indicate that potato plants grown at moderately elevated temperatures do not exhibit classic symptoms of abiotic stress but that tuber development responds via a diversity of biochemical and molecular signals.

  8. Development of sensors for monitoring oxygen and free radicals in plant physiology

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Prachee

    Oxygen plays a critical role in the physiology of photosynthetic organisms, including bioenergetics, metabolism, development, and stress response. Oxygen levels affect photosynthesis, respiration, and alternative oxidase pathways. Likewise, the metabolic rate of spatially distinct plant cells (and therefore oxygen flux) is known to be affected by biotic stress (e.g., herbivory) and environmental stress (e.g., salt/nutrient stress). During aerobic metabolism, cells produce reactive oxygen species (ROS) as a by product. Plants also produce ROS during adaptation to stress (e.g., abscisic acid (ABA) mediated stress responses). If stress conditions are prolonged, ROS levels surpass the capacity of detoxifying mechanisms within the cell, resulting in oxidative damage. While stress response pathways such as ABA-mediated mechanisms have been well characterized (e.g., water stress, inhibited shoot growth, synthesis of storage proteins in seeds), the connection between ROS production, oxygen metabolism and stress response remains unknown. In part, this is because details of oxygen transport at the interface of cell(s) and the surrounding microenvironment remains nebulous. The overall goal of this research was to develop oxygen and Free radical sensors for studying stress signaling in plants. Recent developments in nanomaterials and data acquisition systems were integrated to develop real-time, non-invasive oxygen and Free radical sensors. The availability of these sensors for plant physiologists is an exciting opportunity to probe the functional realm of cells and tissues in ways that were not previously possible.

  9. NaCl-induced physiological and biochemical adaptative mechanisms in the ornamental Myrtus communis L. plants.

    PubMed

    Acosta-Motos, José Ramón; Diaz-Vivancos, Pedro; Álvarez, Sara; Fernández-García, Nieves; Sánchez-Blanco, María Jesús; Hernández, José Antonio

    2015-07-01

    Physiological and biochemical changes in Myrtus communis L. plants after being subjected to different solutions of NaCl (44, and 88 mM) for up to 30 days (Phase I) and after recovery from the salinity period (Phase II) were studied. Myrtle plants showed salinity tolerance by displaying a series of adaptative mechanisms to cope with salt-stress, including controlled ion homeostasis, the increase in root/shoot ratio, the reduction of water potentials and stomatal conductance to limit water loss. In addition, they displayed different strategies to protect the photosynthetic machinery, including limiting toxic ion accumulation in leaves, increase in chlorophyll content, and changes in chlorophyll fluorescence parameters, leaf anatomy and increases in catalase activity. Anatomical modifications in leaves, including a decrease in spongy parenchyma and increased intercellular spaces, allow CO2 diffusion in a situation of reduced stomatal aperture. In spite of all these changes, salinity produced oxidative stress in myrtle plants as monitored by increases in oxidative stress parameter values. The post-recovery period is perceived as a new stress situation, as observed through effects on plant growth and alterations in non-photochemical quenching parameters and lipid peroxidation values.

  10. Phenotypical, physiological and biochemical analyses provide insight into selenium-induced phytotoxicity in rice plants.

    PubMed

    Mostofa, Mohammad Golam; Hossain, Mohammad Anwar; Siddiqui, Md Nurealam; Fujita, Masayuki; Tran, Lam-Son Phan

    2017-03-11

    The present study investigated the phenotypical, physiological and biochemical changes of rice plants exposed to high selenium (Se) concentrations to gain an insight into Se-induced phytotoxicity. Results showed that exposure of rice plants to excessive Se resulted in growth retardation and biomass reduction in connection with the decreased levels of chlorophyll, carotenoids and soluble proteins. The reduced water status and an associated increase in sugar and proline levels indicated Se-induced osmotic stress in rice plants. Measurements of Se contents in roots, leaf sheaths and leaves revealed that Se was highly accumulated in leaves followed by leaf sheaths and roots. Se also potentiated its toxicity by impairing oxidative metabolism, as evidenced by enhanced accumulation of hydrogen peroxide, superoxide and lipid peroxidation product. Se toxicity also displayed a desynchronized antioxidant system by elevating the level of glutathione and the activities of superoxide dismutase, glutathione-S-transferase and glutathione peroxidase, whereas decreasing the level of ascorbic acid and the activities of catalase, glutathione reductase and dehydroascorbate reductase. Furthermore, Se triggered methylglyoxal toxicity by inhibiting the activities of glyoxalases I and II, particularly at higher concentrations of Se. Collectively, our results suggest that excessive Se caused phytotoxic effects on rice plants by inducing chlorosis, reducing sugar, protein and antioxidant contents, and exacerbating oxidative stress and methylglyoxal toxicity. Accumulation levels of Se, proline and glutathione could be considered as efficient biomarkers to indicate degrees of Se-induced phytotoxicity in rice, and perhaps in other crops.

  11. Effects of Three Fire-Suppressant Foams on the Germination and Physiological Responses of Plants

    NASA Astrophysics Data System (ADS)

    Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

    2014-10-01

    Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

  12. Effects of three fire-suppressant foams on the germination and physiological responses of plants.

    PubMed

    Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

    2014-10-01

    Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

  13. Mechanisms and effective control of physiological browning phenomena in plant cell cultures.

    PubMed

    Dong, Yan-Shan; Fu, Chun-Hua; Su, Peng; Xu, Xiang-Ping; Yuan, Jie; Wang, Sheng; Zhang, Meng; Zhao, Chun-Fang; Yu, Long-Jiang

    2016-01-01

    Browning phenomena are ubiquitous in plant cell cultures that severely hamper scientific research and widespread application of plant cell cultures. Up to now, this problem still has not been well controlled due to the unclear browning mechanisms in plant cell cultures. In this paper, the mechanisms were investigated using two typical materials with severe browning phenomena, Taxus chinensis and Glycyrrhiza inflata cells. Our results illustrated that the browning is attributed to a physiological enzymatic reaction, and phenolic biosynthesis regulated by sugar plays a decisive role in the browning. Furthermore, to confirm the specific compounds which participate in the enzymatic browning reaction, transcriptional profile and metabolites of T. chinensis cells, and UV scanning and high-performance liquid chromatography-mass spectrometry (HPLC-MS) profile of the browning compounds extracted from the brown-turned medium were analyzed, flavonoids derived from phenylpropanoid pathway were found to be the main compounds, and myricetin and quercetin were deduced to be the main substrates of the browning reaction. Inhibition of flavonoid biosynthesis can prevent the browning occurrence, and the browning is effectively controlled via blocking flavonoid biosynthesis by gibberellic acid (GA3 ) as an inhibitor, which further confirms that flavonoids mainly contribute to the browning. On the basis above, a model elucidating enzymatic browning mechanisms in plant cell cultures was put forward, and effective control approaches were presented.

  14. The impact of Ni on the physiology of a Mediterranean Ni-hyperaccumulating plant.

    PubMed

    Roccotiello, Enrica; Serrano, Helena Cristina; Mariotti, Mauro Giorgio; Branquinho, Cristina

    2016-06-01

    High nickel (Ni) levels exert toxic effects on plant growth and plant water content, thus affecting photosynthesis. In a pot experiment, we investigated the effect of the Ni concentration on the physiological characteristics of the Ni hyperaccumulator Alyssoides utriculata when grown on a vermiculite substrate in the presence of different external Ni concentrations (0-500 mg Ni L(-1)). The results showed that the Ni concentration was higher in leaves than in roots, as evidenced by a translocation factor = 3 and a bioconcentration factor = 10. At the highest concentration tested (500 mg Ni L(-1)), A. utriculata accumulated 1100 mg Ni per kilogram in its leaves, without an effects on its biomass. Plant water content increased significantly with Ni accumulation. Ni treatment did not, or only slightly, affected chlorophyll fluorescence parameters. The photosynthetic efficiency (FV/FM) of A. utriculata was stable between Ni treatments (always ≥ 0.8) and the photosynthetic performance of the plant under Ni stress remained high (performance index = 1.5). These findings support that A. utriculata has several mechanisms to avoid severe damage to its photosynthetic apparatus, confirming the tolerance of this species to Ni under hyperaccumulation.

  15. Improving intercropping: a synthesis of research in agronomy, plant physiology and ecology.

    PubMed

    Brooker, Rob W; Bennett, Alison E; Cong, Wen-Feng; Daniell, Tim J; George, Timothy S; Hallett, Paul D; Hawes, Cathy; Iannetta, Pietro P M; Jones, Hamlyn G; Karley, Alison J; Li, Long; McKenzie, Blair M; Pakeman, Robin J; Paterson, Eric; Schöb, Christian; Shen, Jianbo; Squire, Geoff; Watson, Christine A; Zhang, Chaochun; Zhang, Fusuo; Zhang, Junling; White, Philip J

    2015-04-01

    Intercropping is a farming practice involving two or more crop species, or genotypes, growing together and coexisting for a time. On the fringes of modern intensive agriculture, intercropping is important in many subsistence or low-input/resource-limited agricultural systems. By allowing genuine yield gains without increased inputs, or greater stability of yield with decreased inputs, intercropping could be one route to delivering ‘sustainable intensification’. We discuss how recent knowledge from agronomy, plant physiology and ecology can be combined with the aim of improving intercropping systems. Recent advances in agronomy and plant physiology include better understanding of the mechanisms of interactions between crop genotypes and species – for example, enhanced resource availability through niche complementarity. Ecological advances include better understanding of the context-dependency of interactions, the mechanisms behind disease and pest avoidance, the links between above- and below-ground systems, and the role of microtopographic variation in coexistence. This improved understanding can guide approaches for improving intercropping systems, including breeding crops for intercropping. Although such advances can help to improve intercropping systems, we suggest that other topics also need addressing. These include better assessment of the wider benefits of intercropping in terms of multiple ecosystem services, collaboration with agricultural engineering, and more effective interdisciplinary research.

  16. A Computer-Assisted Personalized Approach in an Undergraduate Plant Physiology Class1

    PubMed Central

    Artus, Nancy N.; Nadler, Kenneth D.

    1999-01-01

    We used Computer-Assisted Personalized Approach (CAPA), a networked teaching and learning tool that generates computer individualized homework problem sets, in our large-enrollment introductory plant physiology course. We saw significant improvement in student examination performance with regular homework assignments, with CAPA being an effective and efficient substitute for hand-graded homework. Using CAPA, each student received a printed set of similar but individualized problems of a conceptual (qualitative) and/or quantitative nature with quality graphics. Because each set of problems is unique, students were encouraged to work together to clarify concepts but were required to do their own work for credit. Students could enter answers multiple times without penalty, and they were able to obtain immediate feedback and hints until the due date. These features increased student time on task, allowing higher course standards and student achievement in a diverse student population. CAPA handles routine tasks such as grading, recording, summarizing, and posting grades. In anonymous surveys, students indicated an overwhelming preference for homework in CAPA format, citing several features such as immediate feedback, multiple tries, and on-line accessibility as reasons for their preference. We wrote and used more than 170 problems on 17 topics in introductory plant physiology, cataloging them in a computer library for general access. Representative problems are compared and discussed. PMID:10198076

  17. Mathematical literacy in Plant Physiology undergraduates: results of interventions aimed at improving students' performance

    NASA Astrophysics Data System (ADS)

    Vila, Francisca; Sanz, Amparo

    2013-09-01

    The importance of mathematical literacy in any scientific career is widely recognized. However, various studies report lack of numeracy and mathematical literacy in students from various countries. In the present work, we present a detailed study of the mathematical literacy of Spanish undergraduate students of Biology enrolled in a Plant Physiology course. We have performed individual analyses of results obtained during the period 2000-2011, for questions in the examinations requiring and not requiring mathematical skills. Additionally, we present the outcome of two interventions introduced with the aim of helping students improve their prospects for success in the course. Our results confirm previous research showing students' deficiencies in mathematical skills. However, the scores obtained for mathematical questions in the examinations are good predictors of the final grades attained in Plant Physiology, as there are strong correlations at the individual level between results for questions requiring and not requiring mathematical skills. The introduction of a laboratory session devoted to strengthening the application of students' previously acquired mathematical knowledge did not change significantly the results obtained for mathematical questions. Since mathematical abilities of students entering university have declined in recent years, this intervention may have helped to maintain students' performance to a level comparable to that of previous years. The outcome of self-assessment online tests indicates that although Mathematics anxiety is lower than during examinations, the poor results obtained for questions requiring mathematical skills are, at least in part, due to a lack of self-efficacy.

  18. Desiccation-induced physiological and biochemical changes in resurrection plant, Selaginella bryopteris.

    PubMed

    Pandey, Vivek; Ranjan, Sanjay; Deeba, Farah; Pandey, Ashutosh K; Singh, Ruchi; Shirke, Pramod A; Pathre, Uday V

    2010-11-01

    Selaginella bryopteris is a lycophyte resurrection plant, which incurves during desiccation and recovers on availability of moisture. The aim of the study was to test and understand the various physiological and biochemical changes the fronds undergo during desiccation and rehydration, to get an insight as to how this plant adapts and survives through the dry phase. Upon desiccation, S. bryopteris fronds showed drastic inhibition in net photosynthesis (A) and maximal photochemical efficiency of PSII (F(v)/F(m)) however, chlorophyll content did not show much variation. Dark respiration (R(d)) continued even at 10% relative water content (RWC), and showed a burst after rehydration, which is proposed to be crucial to establish protection mechanisms. Desiccation caused an enhanced production of reactive oxygen species (ROS) and increased lipid peroxidation. Proline accumulation increased substantially by 11-fold. Sucrose and starch contents decreased upon desiccation as compared to control. The antioxidative enzymes viz. superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) along with soluble acid invertase increased during desiccation. S. bryopteris shows mechanical as well as physiological mechanisms for tolerance to extreme levels of desiccation stress. The rapid and almost complete recovery of F(v)/F(m) after rehydration clearly indicates the absence of marked photoinhibitory or thermal injury to PSII during desiccation. This along with the homoiochlorophyllous characteristics enables S. bryopteris to recover its A. The antioxidant metabolism further plays an important role in the desiccation tolerance of S. bryopteris.

  19. Joint control of terrestrial gross primary productivity by plant phenology and physiology.

    PubMed

    Xia, Jianyang; Niu, Shuli; Ciais, Philippe; Janssens, Ivan A; Chen, Jiquan; Ammann, Christof; Arain, Altaf; Blanken, Peter D; Cescatti, Alessandro; Bonal, Damien; Buchmann, Nina; Curtis, Peter S; Chen, Shiping; Dong, Jinwei; Flanagan, Lawrence B; Frankenberg, Christian; Georgiadis, Teodoro; Gough, Christopher M; Hui, Dafeng; Kiely, Gerard; Li, Jianwei; Lund, Magnus; Magliulo, Vincenzo; Marcolla, Barbara; Merbold, Lutz; Montagnani, Leonardo; Moors, Eddy J; Olesen, Jørgen E; Piao, Shilong; Raschi, Antonio; Roupsard, Olivier; Suyker, Andrew E; Urbaniak, Marek; Vaccari, Francesco P; Varlagin, Andrej; Vesala, Timo; Wilkinson, Matthew; Weng, Ensheng; Wohlfahrt, Georg; Yan, Liming; Luo, Yiqi

    2015-03-03

    Terrestrial gross primary productivity (GPP) varies greatly over time and space. A better understanding of this variability is necessary for more accurate predictions of the future climate-carbon cycle feedback. Recent studies have suggested that variability in GPP is driven by a broad range of biotic and abiotic factors operating mainly through changes in vegetation phenology and physiological processes. However, it is still unclear how plant phenology and physiology can be integrated to explain the spatiotemporal variability of terrestrial GPP. Based on analyses of eddy-covariance and satellite-derived data, we decomposed annual terrestrial GPP into the length of the CO2 uptake period (CUP) and the seasonal maximal capacity of CO2 uptake (GPPmax). The product of CUP and GPPmax explained >90% of the temporal GPP variability in most areas of North America during 2000-2010 and the spatial GPP variation among globally distributed eddy flux tower sites. It also explained GPP response to the European heatwave in 2003 (r(2) = 0.90) and GPP recovery after a fire disturbance in South Dakota (r(2) = 0.88). Additional analysis of the eddy-covariance flux data shows that the interbiome variation in annual GPP is better explained by that in GPPmax than CUP. These findings indicate that terrestrial GPP is jointly controlled by ecosystem-level plant phenology and photosynthetic capacity, and greater understanding of GPPmax and CUP responses to environmental and biological variations will, thus, improve predictions of GPP over time and space.

  20. Joint control of terrestrial gross primary productivity by plant phenology and physiology

    PubMed Central

    Xia, Jianyang; Niu, Shuli; Ciais, Philippe; Janssens, Ivan A.; Chen, Jiquan; Ammann, Christof; Arain, Altaf; Blanken, Peter D.; Cescatti, Alessandro; Bonal, Damien; Buchmann, Nina; Curtis, Peter S.; Chen, Shiping; Dong, Jinwei; Flanagan, Lawrence B.; Frankenberg, Christian; Georgiadis, Teodoro; Gough, Christopher M.; Hui, Dafeng; Kiely, Gerard; Li, Jianwei; Lund, Magnus; Magliulo, Vincenzo; Marcolla, Barbara; Merbold, Lutz; Olesen, Jørgen E.; Piao, Shilong; Raschi, Antonio; Roupsard, Olivier; Suyker, Andrew E.; Vaccari, Francesco P.; Varlagin, Andrej; Vesala, Timo; Wilkinson, Matthew; Weng, Ensheng; Yan, Liming; Luo, Yiqi

    2015-01-01

    Terrestrial gross primary productivity (GPP) varies greatly over time and space. A better understanding of this variability is necessary for more accurate predictions of the future climate–carbon cycle feedback. Recent studies have suggested that variability in GPP is driven by a broad range of biotic and abiotic factors operating mainly through changes in vegetation phenology and physiological processes. However, it is still unclear how plant phenology and physiology can be integrated to explain the spatiotemporal variability of terrestrial GPP. Based on analyses of eddy–covariance and satellite-derived data, we decomposed annual terrestrial GPP into the length of the CO2 uptake period (CUP) and the seasonal maximal capacity of CO2 uptake (GPPmax). The product of CUP and GPPmax explained >90% of the temporal GPP variability in most areas of North America during 2000–2010 and the spatial GPP variation among globally distributed eddy flux tower sites. It also explained GPP response to the European heatwave in 2003 (r2 = 0.90) and GPP recovery after a fire disturbance in South Dakota (r2 = 0.88). Additional analysis of the eddy–covariance flux data shows that the interbiome variation in annual GPP is better explained by that in GPPmax than CUP. These findings indicate that terrestrial GPP is jointly controlled by ecosystem-level plant phenology and photosynthetic capacity, and greater understanding of GPPmax and CUP responses to environmental and biological variations will, thus, improve predictions of GPP over time and space. PMID:25730847

  1. Physiological effects of climate warming on flowering plants and insect pollinators and potential consequences for their interactions.

    PubMed

    Scaven, Victoria L; Rafferty, Nicole E

    2013-01-01

    Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interactions between them has led to a recent surge in research. Much of this research has addressed the consequences of warming for phenological and distributional shifts. In contrast, relatively little is known about the physiological responses of plants and insect pollinators to climate warming and, in particular, how these responses might affect plant-pollinator interactions. Here, we summarize the direct physiological effects of temperature on flowering plants and pollinating insects to highlight ways in which plant and pollinator responses could affect floral resources for pollinators, and pollination success for plants, respectively. We also consider the overall effects of these responses on plant-pollinator interaction networks. Plant responses to warming, which include altered flower, nectar, and pollen production, could modify floral resource availability and reproductive output of pollinating insects. Similarly, pollinator responses, such as altered foraging activity, body size, and life span, could affect patterns of pollen flow and pollination success of flowering plants. As a result, network structure could be altered as interactions are gained and lost, weakened and strengthened, even without the gain or loss of species or temporal overlap. Future research that addresses not only how plant and pollinator physiology are affected by warming but also how responses scale up to affect interactions and networks should allow us to better understand and predict the effects of climate change on this important ecosystem service.

  2. Plant physiology and proteomics reveals the leaf response to drought in alfalfa (Medicago sativa L.)

    PubMed Central

    Aranjuelo, Iker; Molero, Gemma; Erice, Gorka; Avice, Jean Christophe; Nogués, Salvador

    2011-01-01

    Despite its relevance, protein regulation, metabolic adjustment, and the physiological status of plants under drought is not well understood in relation to the role of nitrogen fixation in nodules. In this study, nodulated alfalfa plants were exposed to drought conditions. The study determined the physiological, metabolic, and proteomic processes involved in photosynthetic inhibition in relation to the decrease in nitrogenase (Nase) activity. The deleterious effect of drought on alfalfa performance was targeted towards photosynthesis and Nase activity. At the leaf level, photosynthetic inhibition was mainly caused by the inhibition of Rubisco. The proteomic profile and physiological measurements revealed that the reduced carboxylation capacity of droughted plants was related to limitations in Rubisco protein content, activation state, and RuBP regeneration. Drought also decreased amino acid content such as asparagine, and glutamic acid, and Rubisco protein content indicating that N availability limitations were caused by Nase activity inhibition. In this context, drought induced the decrease in Rubisco binding protein content at the leaf level and proteases were up-regulated so as to degrade Rubisco protein. This degradation enabled the reallocation of the Rubisco-derived N to the synthesis of amino acids with osmoregulant capacity. Rubisco degradation under drought conditions was induced so as to remobilize Rubisco-derived N to compensate for the decrease in N associated with Nase inhibition. Metabolic analyses showed that droughted plants increased amino acid (proline, a major compound involved in osmotic regulation) and soluble sugar (D-pinitol) levels to contribute towards the decrease in osmotic potential (Ψs). At the nodule level, drought had an inhibitory effect on Nase activity. This decrease in Nase activity was not induced by substrate shortage, as reflected by an increase in total soluble sugars (TSS) in the nodules. Proline accumulation in the nodule

  3. Effects of arbuscular-mycorrhizal glomus species on drought tolerance: physiological and nutritional plant responses.

    PubMed

    Ruiz-Lozano, J M; Azcon, R; Gomez, M

    1995-02-01

    The tolerance of lettuce plants (Lactuca sativa L. cv. Romana) to drought stress differed with the arbuscular-mycorrhizal fungal isolate with which the plants were associated. Seven fungal species belonging to the genus Glomus were studied for their ability to enhance the drought tolerance of lettuce plants. These fungi had different traits that affected the drought resistance of host plants. The ranking of arbuscular-mycorrhizal fungal effects on drought tolerance, based on the relative decreases in shoot dry weight, was as follows: Glomus deserticola > Glomus fasciculatum > Glomus mosseae > Glomus etunicatum > Glomus intraradices > Glomus caledonium > Glomus occultum. In this comparative study specific mycorrhizal fungi had consistent effects on plant growth, mineral uptake, the CO(inf2) exchange rate, water use efficiency, transpiration, stomatal conductance, photosynthetic phosphorus use efficiency, and proline accumulation under either well-watered or drought-stressed conditions. The ability of the isolates to maintain plant growth effectively under water stress conditions was related to higher transpiration rates, levels of leaf conductance, and proline, N, and P contents. Differences in proline accumulation in leaves among the fungal symbioses suggested that the fungi were able to induce different degrees of osmotic adjustment. The detrimental effects of drought were not related to decreases in photosynthesis or water use efficiency. Neither of these parameters was related to P nutrition. The differences in P and K acquisition, transpiration, and stomatal conductance were related to the mycorrhizal efficiencies of the different fungi. Our observations revealed the propensities of different Glomus species to assert their protective effects during plant water stress. The greater effectiveness of G. deserticola in improving water deficit tolerance was associated with the lowest level of growth reduction (9%) under stress conditions. The growth of plants

  4. Effects of Arbuscular-Mycorrhizal Glomus Species on Drought Tolerance: Physiological and Nutritional Plant Responses

    PubMed Central

    Ruiz-Lozano, J. M.; Azcon, R.; Gomez, M.

    1995-01-01

    The tolerance of lettuce plants (Lactuca sativa L. cv. Romana) to drought stress differed with the arbuscular-mycorrhizal fungal isolate with which the plants were associated. Seven fungal species belonging to the genus Glomus were studied for their ability to enhance the drought tolerance of lettuce plants. These fungi had different traits that affected the drought resistance of host plants. The ranking of arbuscular-mycorrhizal fungal effects on drought tolerance, based on the relative decreases in shoot dry weight, was as follows: Glomus deserticola > Glomus fasciculatum > Glomus mosseae > Glomus etunicatum > Glomus intraradices > Glomus caledonium > Glomus occultum. In this comparative study specific mycorrhizal fungi had consistent effects on plant growth, mineral uptake, the CO(inf2) exchange rate, water use efficiency, transpiration, stomatal conductance, photosynthetic phosphorus use efficiency, and proline accumulation under either well-watered or drought-stressed conditions. The ability of the isolates to maintain plant growth effectively under water stress conditions was related to higher transpiration rates, levels of leaf conductance, and proline, N, and P contents. Differences in proline accumulation in leaves among the fungal symbioses suggested that the fungi were able to induce different degrees of osmotic adjustment. The detrimental effects of drought were not related to decreases in photosynthesis or water use efficiency. Neither of these parameters was related to P nutrition. The differences in P and K acquisition, transpiration, and stomatal conductance were related to the mycorrhizal efficiencies of the different fungi. Our observations revealed the propensities of different Glomus species to assert their protective effects during plant water stress. The greater effectiveness of G. deserticola in improving water deficit tolerance was associated with the lowest level of growth reduction (9%) under stress conditions. The growth of plants

  5. Physiological and growth responses of C3 and C4 plants at the Pleistocene glacial maximum

    SciTech Connect

    Strain, B.R.

    1995-06-01

    A C3 plant (Abutilon theophrasti) and a C4 plant (Amaranthus retroflexus) were grown from seed in the Duke University Phytotron under four CO2 concentrations (15 Pa, below the Pleistocene minimum), 27 Pa (pre-industrial), 35 Pa (current), and 70 Pa (future) to examine photosynthetic, growth and reproduction responses of annual plants to historic and future levels of CO2. Net photosynthesis and growth were greatly inhibited at 15 Pa and greatly stimulated at 70 Pa. in the C3 Abutilon but only slightly affected in the C4 Amaranthus. Flower bud initiation was not affected by CO2 treatment in either species but all flower buds in 15 Pa CO2 aborted in the C3 within two days of appearance while no inhibition of reproduction was observed at low CO2 in the C4. Differences in physiology, growth and reproduction to the low levels of atmospheric CO2 of the Pleistocene suggest that competitive interactions of C3 and C4 annuals have changed through geologic time. A major question concerning the survival and evolution of obligate C3 annuals during the CO2 minima of the Pleistocene is raised by the results of this study.

  6. Eco-physiological Effects of Atmospheric Ozone and Polycyclic Aromatic Hydrocarbons (PAHs) on Plants

    NASA Astrophysics Data System (ADS)

    Bandai, S.; Sakugawa, H. H.

    2012-12-01

    [Introduction] Tropospheric ozone is one of most concerned air pollutant, by causing damage to trees and crops. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants found in various environmental compartments. Photo-induced toxicity of PAHs can be driven from formation of intracellular single oxygen and other reactive oxygen intermediates (ROI) leading to biological damages.(1) In the present study, we measured photosynthesis rate and other variables to investigate the effects of ozone and PAHs on the eco-physiological status of plants such as eggplant, common bean and strawberry. Plants treated with the single or combined air pollutants are expected to exhibit altered physiological, morphological and possibly growth changes. [Materials and Methods] We performed three exposure experiments. Exp.1. Eggplant (Solanum melongena) seedlings, were placed in the open-top chambers (n=6 plants/treatment). Treatment system was ozone (O)(120ppb), phenanthrene (P)(10μM), O+P, fluoranthene (F)(10μM), O+F, mannitol (M)(1mM) and the control (Milli-Q water)(C). P, F and M were sprayed three times weekly on the foliage part of eggplant. Average volume sprayed per seedling was 50mL. The treatment period was 30days and [AOT 40 (Accumulated exposure over a threshold of 40 ppb)]=28.8 ppmh. Exp.2, Common bean (Phaseolus vulgaris L.) seedlings were used (n=5 plants/treatment). The treatment system was the same as Exp.1. The treatment period was 40days and [AOT 40]=38.4ppmh. Exp.3. Strawberry (Fragaria L.) seedlings were used (n=5 plants/treatment). Treatment system was O (120ppb), F(10μM), O+F, F+M, O+M and C. The treatment period was 90days and [AOT 40]=86.4ppmh. Ecophysiological variables examined were photosynthesis rate measured at saturated irradiance (Amax), stomatal conductance to water vapour (gs), internal CO2 concentration (Ci), photochemical efficiency of PS2 in the dark (Fv/Fm), chlorophyll contents, visual symptom assessment and elemental composition in the

  7. Gravity Plant Physiology Facility (GPPF) Team in the Spacelab Payload Operations Control Center (SL

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The primary payload for Space Shuttle Mission STS-42, launched January 22, 1992, was the International Microgravity Laboratory-1 (IML-1), a pressurized manned Spacelab module. The goal of IML-1 was to explore in depth the complex effects of weightlessness of living organisms and materials processing. Around-the-clock research was performed on the human nervous system's adaptation to low gravity and effects of microgravity on other life forms such as shrimp eggs, lentil seedlings, fruit fly eggs, and bacteria. Materials processing experiments were also conducted, including crystal growth from a variety of substances such as enzymes, mercury iodide, and a virus. The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Featured is the Gravity Plant Physiology Facility (GPPF) team in the SL POCC during the IML-1 mission.

  8. Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter

    PubMed Central

    Schmitz, Oswald J.; Bradford, Mark A.; Strickland, Michael S.; Hawlena, Dror

    2013-01-01

    The quantity and quality of detritus entering the soil determines the rate of decomposition by microbial communities as well as recycle rates of nitrogen (N) and carbon (C) sequestration1,2. Plant litter comprises the majority of detritus3, and so it is assumed that decomposition is only marginally influenced by biomass inputs from animals such as herbivores and carnivores4,5. However, carnivores may influence microbial decomposition of plant litter via a chain of interactions in which predation risk alters the physiology of their herbivore prey that in turn alters soil microbial functioning when the herbivore carcasses are decomposed6. A physiological stress response by herbivores to the risk of predation can change the C:N elemental composition of herbivore biomass7,8,9 because stress from predation risk increases herbivore basal energy demands that in nutrient-limited systems forces herbivores to shift their consumption from N-rich resources to support growth and reproduction to C-rich carbohydrate resources to support heightened metabolism6. Herbivores have limited ability to store excess nutrients, so stressed herbivores excrete N as they increase carbohydrate-C consumption7. Ultimately, prey stressed by predation risk increase their body C:N ratio7,10, making them poorer quality resources for the soil microbial pool likely due to lower availability of labile N for microbial enzyme production6. Thus, decomposition of carcasses of stressed herbivores has a priming effect on the functioning of microbial communities that decreases subsequent ability to of microbes to decompose plant litter6,10,11. We present the methodology to evaluate linkages between predation risk and litter decomposition by soil microbes. We describe how to: induce stress in herbivores from predation risk; measure those stress responses, and measure the consequences on microbial decomposition. We use insights from a model grassland ecosystem comprising the hunting spider predator (Pisuarina

  9. Modelling of salad plants growth and physiological status in vitamin space greenhouse during lighting regime optimization

    NASA Astrophysics Data System (ADS)

    Konovalova, Irina; Berkovich, Yuliy A.; Smolyanina, Svetlana; Erokhin, Alexei; Yakovleva, Olga; Lapach, Sergij; Radchenko, Stanislav; Znamenskii, Artem; Tarakanov, Ivan

    2016-07-01

    The efficiency of the photoautotrophic element as part of bio-engineering life-support systems is determined substantially by lighting regime. The artificial light regime optimization complexity results from the wide range of plant physiological functions controlled by light: trophic, informative, biosynthetical, etc. An average photosynthetic photon flux density (PPFD), light spectral composition and pulsed light effects on the crop growth and plant physiological status were studied in the multivariate experiment, including 16 independent experiments in 3 replicates. Chinese cabbage plants (Brassica chinensis L.), cultivar Vesnianka, were grown during 24 days in a climatic chamber under white and red light-emitting diodes (LEDs): photoperiod 24 h, PPFD from 260 to 500 µM/(m ^{2}*s), red light share in the spectrum varying from 33% to 73%, pulsed (pulse period from 30 to 501 µs) and non-pulsed lighting. The regressions of plant photosynthetic and biochemical indexes as well as the crop specific productivity in response to the selected parameters of lighting regime were calculated. Developed models of crop net photosynthesis and dark respiration revealed the most intense gas exchange area corresponding to PPFD level 450 - 500 µM/(m ^{2}*s) with red light share in the spectrum about 60% and the pulse length 30 µs with a pulse period from 300 to 400 µs. Shoot dry weight increased monotonically in response to the increasing PPFD and changed depending on the pulse period under stabilized PPFD level. An increase in ascorbic acid content in the shoot biomass was revealed when increasing red light share in spectrum from 33% to 73%. The lighting regime optimization criterion (Q) was designed for the vitamin space greenhouse as the maximum of a crop yield square on its ascorbic acid concentration, divided by the light energy consumption. The regression model of optimization criterion was constructed based on the experimental data. The analysis of the model made it

  10. Physiologically available cyanide (PAC) in manufactured gas plant waste and soil samples

    SciTech Connect

    Magee, B.; Taft, A.; Ratliff, W.; Kelley, J.; Sullivan, J.; Pancorbo, O.

    1995-12-31

    Iron-complexed cyanide compounds, such as ferri-ferrocyanide (Prussian Blue), are wastes associated with former manufactured gas plant (MGP) facilities. When tested for total cyanide, these wastes often show a high total cyanide content. Because simple cyanide salts are acutely toxic, cyanide compounds can be the subject of concern. However, Prussian Blue and related species are known to have a low order of human and animal toxicity. Toxicology data on complexed cyanides will be presented. Another issue regarding Prussian Blue and related species is that the total cyanide method does not accurately represent the amount of free cyanide released from these cyanide species. The method involves boiling the sample in an acidic solution under vacuum to force the formation of HCN gas. Thus, Prussian Blue, which is known to be low in toxicity, cannot be properly evaluated with current methods. The Massachusetts Natural Gas Council initiated a program with the Massachusetts Department of Environmental Protection to develop a method that would define the amount of cyanide that is able to be converted into hydrogen cyanide under the pH conditions of the stomach. It is demonstrated that less than 1% of the cyanide present in Prussian Blue samples and soils from MGP sites can be converted to HCN under the conditions of the human stomach. The physiologically available cyanide method has been designed to be executed at a higher temperature for one hour. It is shown that physiologically available cyanide in MGP samples is < 5--15% of total cyanide.

  11. Instrumentation enabling study of plant physiological response to elevated night temperature

    PubMed Central

    Mohammed, Abdul R; Tarpley, Lee

    2009-01-01

    Background Global climate warming can affect functioning of crops and plants in the natural environment. In order to study the effects of global warming, a method for applying a controlled heating treatment to plant canopies in the open field or in the greenhouse is needed that can accept either square wave application of elevated temperature or a complex prescribed diurnal or seasonal temperature regime. The current options are limited in their accuracy, precision, reliability, mobility or cost and scalability. Results The described system uses overhead infrared heaters that are relatively inexpensive and are accurate and precise in rapidly controlling the temperature. Remote computer-based data acquisition and control via the internet provides the ability to use complex temperature regimes and real-time monitoring. Due to its easy mobility, the heating system can randomly be allotted in the open field or in the greenhouse within the experimental setup. The apparatus has been successfully applied to study the response of rice to high night temperatures. Air temperatures were maintained within the set points ± 0.5°C. The incorporation of the combination of air-situated thermocouples, autotuned proportional integrative derivative temperature controllers and phase angled fired silicon controlled rectifier power controllers provides very fast proportional heating action (i.e. 9 ms time base), which avoids prolonged or intense heating of the plant material. Conclusion The described infrared heating system meets the utilitarian requirements of a heating system for plant physiology studies in that the elevated temperature can be accurately, precisely, and reliably controlled with minimal perturbation of other environmental factors. PMID:19519906

  12. Plant phenomics and the need for physiological phenotyping across scales to narrow the genotype-to-phenotype knowledge gap.

    PubMed

    Großkinsky, Dominik K; Svensgaard, Jesper; Christensen, Svend; Roitsch, Thomas

    2015-09-01

    Plants are affected by complex genome×environment×management interactions which determine phenotypic plasticity as a result of the variability of genetic components. Whereas great advances have been made in the cost-efficient and high-throughput analyses of genetic information and non-invasive phenotyping, the large-scale analyses of the underlying physiological mechanisms lag behind. The external phenotype is determined by the sum of the complex interactions of metabolic pathways and intracellular regulatory networks that is reflected in an internal, physiological, and biochemical phenotype. These various scales of dynamic physiological responses need to be considered, and genotyping and external phenotyping should be linked to the physiology at the cellular and tissue level. A high-dimensional physiological phenotyping across scales is needed that integrates the precise characterization of the internal phenotype into high-throughput phenotyping of whole plants and canopies. By this means, complex traits can be broken down into individual components of physiological traits. Since the higher resolution of physiological phenotyping by 'wet chemistry' is inherently limited in throughput, high-throughput non-invasive phenotyping needs to be validated and verified across scales to be used as proxy for the underlying processes. Armed with this interdisciplinary and multidimensional phenomics approach, plant physiology, non-invasive phenotyping, and functional genomics will complement each other, ultimately enabling the in silico assessment of responses under defined environments with advanced crop models. This will allow generation of robust physiological predictors also for complex traits to bridge the knowledge gap between genotype and phenotype for applications in breeding, precision farming, and basic research.

  13. Plastoquinone and Ubiquinone in Plants: Biosynthesis, Physiological Function and Metabolic Engineering

    PubMed Central

    Liu, Miaomiao; Lu, Shanfa

    2016-01-01

    review, we summarize and discuss recent research progresses in the biosynthetic pathways of PQ and UQ and enzymes and their encoding genes involved in side chain elongation and in the second stage of PQ and UQ biosynthesis. Physiological functions of PQ and UQ played in plants as well as the practical application and metabolic engineering of PQ and UQ are also included. PMID:28018418

  14. EDTA reduces the physiological damage of lead on cardoon plants grown hydroponically

    NASA Astrophysics Data System (ADS)

    Hernandez-Allica, J.; Barrutia, O.; Becerril, J. M.; Garbisu, C.

    2003-05-01

    Cardoon seedlings (Cynara cardunculus L.) were grown hydroponically in nutrient solution and exposed to lead (Pb^{2+}: ImM) in the presence of a range of different EDTA concentrations (EDTANa2: 0, 0.5, 1 or 2mM). Analyses were performed to establish whether the coordination of Pb^{2+} transport by EDTA enhances the mobility of this metal within the plant and to determine the toxic effects of these treatments during a phytoextraction process. Net photosynthesis, transpiration rate and stomatal conductance decreased dramatically in plants treated with Pb^{2+} or Pb-EDTA at doses below 1 mM. ln these treatments, most of the Pb^{2+} accumulated in the roots, alld only a very low amount of it was translocated to the shoots. Increasing the EDTA doses up to Pb^{2+} equimolarity, increased the Pb^{2+} shoot content more than 10-fold without any physiological evidence of toxicity. The treatment with higher doses of EDTA (Pb^{2+} 1 mM + EDTA 2 mM) did not show toxicity symptoms, but the Pb^{2+} concentration in the aboveground tissues decreased when compared with the equimolar treatment. The interaction with the absorption of some essential cations such as Ca^{2+} and phytotoxicity on chelated-assisted phytoextraction is discussed.

  15. Distinct physiological responses of tomato and cucumber plants in silicon-mediated alleviation of cadmium stress

    PubMed Central

    Wu, Jiawen; Guo, Jia; Hu, Yanhong; Gong, Haijun

    2015-01-01

    The alleviative effects of silicon (Si) on cadmium (Cd) toxicity were investigated in cucumber (Cucumis sativus L.) and tomato (Solanum lycopersicum L.) grown hydroponically. The growth of both plant species was inhibited by 100 μM Cd, but Si application counteracted the adverse effects on growth. Si application significantly decreased the Cd concentrations in shoots of both species and roots of cucumber. The root-to-shoot transport of Cd was depressed by added Si in tomato whereas it was increased by added Si in cucumber. The total content of organic acids was decreased in tomato leaves but increased in cucumber roots and leaves by Si application under Cd stress. Si application also increased the cell wall polysaccharide levels in the roots of both species under Cd toxicity. Si-mediated changes in levels of organic acids and cell wall polysaccharides might contribute to the differences in Cd transport in the two species. In addition, Si application also mitigated Cd-induced oxidative damage in both species. The results indicate that there were different mechanisms for Si-mediated decrease in shoot Cd accumulation: in tomato, Si supply decreased root-to-shoot Cd transport; whereas in cucumber, Si supply reduced the Cd uptake by roots. It is suggested that Si-mediated Cd tolerance is associated with different physiological responses in tomato and cucumber plants. PMID:26136764

  16. The response of marigold (Tagetes erecta Linn.) to ozone: impacts on plant growth and leaf physiology.

    PubMed

    Yang, Ning; Wang, Xiaoke; Zheng, Feixiang; Chen, Yuanyuan

    2017-01-01

    Progressively increasing ozone (O3) concentrations pose a potential threat to the value of marigold (Tagetes erecta Linn.), a plant widely used in urban landscaping. The response of marigold to elevated O3 has been reported earlier, but the mechanisms underlying the O3 effect have not been clearly elucidated. In the present study, we exposed marigold "Moonsong Deep Orange" plants to elevated O3, including ambient non-filtered air (NF) plus 60 ppb (NF+60) and 120 ppb (NF+120) O3, to assess visible injury and the possible physiological consequences of this pollutant. Yellow lesions appeared after 4 days under NF+120 treatment and 12 days under NF+60 treatment, with 85.6% and 36.8% of the leaves being injured at harvest time, respectively. Compared with NF, NF+60 inhibited leaf photosynthesis, stem-diameter growth, and biomass production significantly, while the parameters were decreased more by NF+120. Although the stomatal conductance decreased under elevated O3 exposure, the O3 flux into leaves increased by 28.0-104.8% under NF+60 treatment and 57.5-145.6% under NF+120 treatment. The total ascorbic acid (ASA) content increased due to elevated O3 exposure, while the reduced ASA content did not, resulting in a decreased ratio of reduced to total ASA. A lower level of jasmonic acid (JA) was observed under elevated O3 exposure. In conclusion, the impacts of elevated O3 on marigold plants may be ascribed to increased O3 flux into leaves and reduced protective capacity of leaves to convert oxidized to reduced ASA and synthesize endogenous JA.

  17. Plant physiological models of heat, water and photoinhibition stress for climate change modelling and agricultural prediction

    NASA Astrophysics Data System (ADS)

    Nicolas, B.; Gilbert, M. E.; Paw U, K. T.

    2015-12-01

    Soil-Vegetation-Atmosphere Transfer (SVAT) models are based upon well understood steady state photosynthetic physiology - the Farquhar-von Caemmerer-Berry model (FvCB). However, representations of physiological stress and damage have not been successfully integrated into SVAT models. Generally, it has been assumed that plants will strive to conserve water at higher temperatures by reducing stomatal conductance or adjusting osmotic balance, until potentially damaging temperatures and the need for evaporative cooling become more important than water conservation. A key point is that damage is the result of combined stresses: drought leads to stomatal closure, less evaporative cooling, high leaf temperature, less photosynthetic dissipation of absorbed energy, all coupled with high light (photosynthetic photon flux density; PPFD). This leads to excess absorbed energy by Photosystem II (PSII) and results in photoinhibition and damage, neither are included in SVAT models. Current representations of photoinhibition are treated as a function of PPFD, not as a function of constrained photosynthesis under heat or water. Thus, it seems unlikely that current models can predict responses of vegetation to climate variability and change. We propose a dynamic model of damage to Rubisco and RuBP-regeneration that accounts, mechanistically, for the interactions between high temperature, light, and constrained photosynthesis under drought. Further, these predictions are illustrated by key experiments allowing model validation. We also integrated this new framework within the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA). Preliminary results show that our approach can be used to predict reasonable photosynthetic dynamics. For instances, a leaf undergoing one day of drought stress will quickly decrease its maximum quantum yield of PSII (Fv/Fm), but it won't recover to unstressed levels for several days. Consequently, cumulative effect of photoinhibition on photosynthesis can cause

  18. The Use of Light-Emitting Diodes (LEDs) as Green and Red/Far-Red Light Sources in Plant Physiology.

    ERIC Educational Resources Information Center

    Jackson, David L.; And Others

    1985-01-01

    The use of green, red, and far-red light-emitting diodes (LEDs) as light sources for plant physiological studies is outlined and evaluated. Indicates that LED lamps have the advantage over conventional light sources in that they are lightweight, low-cost, portable, easily constructed, and do not require color filters. (Author/DH)

  19. Reversible, partial inactivation of plant betaine aldehyde dehydrogenase by betaine aldehyde: mechanism and possible physiological implications.

    PubMed

    Zárate-Romero, Andrés; Murillo-Melo, Darío S; Mújica-Jiménez, Carlos; Montiel, Carmina; Muñoz-Clares, Rosario A

    2016-04-01

    In plants, the last step in the biosynthesis of the osmoprotectant glycine betaine (GB) is the NAD(+)-dependent oxidation of betaine aldehyde (BAL) catalysed by some aldehyde dehydrogenase (ALDH) 10 enzymes that exhibit betaine aldehyde dehydrogenase (BADH) activity. Given the irreversibility of the reaction, the short-term regulation of these enzymes is of great physiological relevance to avoid adverse decreases in the NAD(+):NADH ratio. In the present study, we report that the Spinacia oleracea BADH (SoBADH) is reversibly and partially inactivated by BAL in the absence of NAD(+)in a time- and concentration-dependent mode. Crystallographic evidence indicates that the non-essential Cys(450)(SoBADH numbering) forms a thiohemiacetal with BAL, totally blocking the productive binding of the aldehyde. It is of interest that, in contrast to Cys(450), the catalytic cysteine (Cys(291)) did not react with BAL in the absence of NAD(+) The trimethylammonium group of BAL binds in the same position in the inactivating or productive modes. Accordingly, BAL does not inactivate the C(450)SSoBADH mutant and the degree of inactivation of the A(441)I and A(441)C mutants corresponds to their very different abilities to bind the trimethylammonium group. Cys(450)and the neighbouring residues that participate in stabilizing the thiohemiacetal are strictly conserved in plant ALDH10 enzymes with proven or predicted BADH activity, suggesting that inactivation by BAL is their common feature. Under osmotic stress conditions, this novel partial and reversible covalent regulatory mechanism may contribute to preventing NAD(+)exhaustion, while still permitting the synthesis of high amounts of GB and avoiding the accumulation of the toxic BAL.

  20. Phenolic metabolites in carnivorous plants: Inter-specific comparison and physiological studies.

    PubMed

    Kováčik, Jozef; Klejdus, Bořivoj; Repčáková, Klára

    2012-03-01

    Despite intensive phytochemical research, data related to the accumulation of phenols in carnivorous plants include mainly qualitative reports. We have quantified phenolic metabolites in three species: Drosera capensis, Dionaea muscipula and Nepenthes anamensis in the "leaf" (assimilatory part) and the "trap" (digestive part). For comparison, commercial green tea was analysed. Phenylalanine ammonia-lyase (PAL) activities in Dionaea and Nepenthes were higher in the trap than in the leaf while the opposite was found in Drosera. Soluble phenols and majority of phenolic acids were mainly accumulated in the trap among species. Flavonoids were abundant in Drosera and Dionaea traps but not in Nepenthes. Phenolic acids were preferentially accumulated in a glycosidically-bound form and gallic acid was the main metabolite. Green tea contained more soluble phenols and phenolic acids but less quercetin. In vitro experiments with Drosera spathulata revealed that nitrogen deficiency enhances PAL activity, accumulation of phenols and sugars while PAL inhibitor (2-aminoindane-2-phosphonic acid) depleted phenols and some amino acids (but free phenylalanine and sugars were elevated). Possible explanations in physiological, biochemical and ecological context are discussed.

  1. Mutual physiological genetic mechanism of plant high water use efficiency and nutrition use efficiency.

    PubMed

    Cao, Hong-Xing; Zhang, Zheng-Bin; Xu, Ping; Chu, Li-Ye; Shao, Hong-Bo; Lu, Zhao-Hua; Liu, Jun-Hong

    2007-05-15

    Water deficiency and lower fertilizer utilization efficiency are major constraints of productivity and yield stability. Improvements of crop water use efficiency (WUE) and nutrient use efficiency (NUE) is becoming an important objective in crop breeding. With the introduction of new physiological and biological approaches, we can better understand the mutual genetics mechanism of high use efficiency of water and nutrient. Much work has been done in past decades mainly including the interactions between different fertilizers and water influences on root characteristics and crop growth. Fertilizer quantity and form were regulated in order to improve crop WUE. The crop WUE and NUE shared the same increment tendency during evolution process; some genes associated with WUE and NUE have been precisely located and marked on the same chromosomes, some genes related to WUE and NUE have been cloned and transferred into wheat and rice and other plants, they can enhance water and nutrient use efficiency. The proteins transporting nutrient and water were identified such as some water channel proteins. The advance on the mechanism of higher water and nutrient use efficiency in crop was reviewed in this article, and it could provide some useful information for further research on WUE and NUE in crop.

  2. A novel ammonia-oxidizing archaeon from wastewater treatment plant: Its enrichment, physiological and genomic characteristics

    NASA Astrophysics Data System (ADS)

    Li, Yuyang; Ding, Kun; Wen, Xianghua; Zhang, Bing; Shen, Bo; Yang, Yunfeng

    2016-03-01

    Ammonia-oxidizing archaea (AOA) are recently found to participate in the ammonia removal processes in wastewater treatment plants (WWTPs), similar to their bacterial counterparts. However, due to lack of cultivated AOA strains from WWTPs, their functions and contributions in these systems remain unclear. Here we report a novel AOA strain SAT1 enriched from activated sludge, with its physiological and genomic characteristics investigated. The maximal 16S rRNA gene similarity between SAT1 and other reported AOA strain is 96% (with “Ca. Nitrosotenuis chungbukensis”), and it is affiliated with Wastewater Cluster B (WWC-B) based on amoA gene phylogeny, a cluster within group I.1a and specific for activated sludge. Our strain is autotrophic, mesophilic (25 °C–33 °C) and neutrophilic (pH 5.0–7.0). Its genome size is 1.62 Mb, with a large fragment inversion (accounted for 68% genomic size) inside. The strain could not utilize urea due to truncation of the urea transporter gene. The lack of the pathways to synthesize usual compatible solutes makes it intolerant to high salinity (>0.03%), but could adapt to low salinity (0.005%) environments. This adaptation, together with possibly enhanced cell-biofilm attachment ability, makes it suitable for WWTPs environment. We propose the name “Candidatus Nitrosotenuis cloacae” for the strain SAT1.

  3. A novel ammonia-oxidizing archaeon from wastewater treatment plant: Its enrichment, physiological and genomic characteristics

    PubMed Central

    Li, Yuyang; Ding, Kun; Wen, Xianghua; Zhang, Bing; Shen, Bo; Yang, Yunfeng

    2016-01-01

    Ammonia-oxidizing archaea (AOA) are recently found to participate in the ammonia removal processes in wastewater treatment plants (WWTPs), similar to their bacterial counterparts. However, due to lack of cultivated AOA strains from WWTPs, their functions and contributions in these systems remain unclear. Here we report a novel AOA strain SAT1 enriched from activated sludge, with its physiological and genomic characteristics investigated. The maximal 16S rRNA gene similarity between SAT1 and other reported AOA strain is 96% (with “Ca. Nitrosotenuis chungbukensis”), and it is affiliated with Wastewater Cluster B (WWC-B) based on amoA gene phylogeny, a cluster within group I.1a and specific for activated sludge. Our strain is autotrophic, mesophilic (25 °C–33 °C) and neutrophilic (pH 5.0–7.0). Its genome size is 1.62 Mb, with a large fragment inversion (accounted for 68% genomic size) inside. The strain could not utilize urea due to truncation of the urea transporter gene. The lack of the pathways to synthesize usual compatible solutes makes it intolerant to high salinity (>0.03%), but could adapt to low salinity (0.005%) environments. This adaptation, together with possibly enhanced cell-biofilm attachment ability, makes it suitable for WWTPs environment. We propose the name “Candidatus Nitrosotenuis cloacae” for the strain SAT1. PMID:27030530

  4. Physiological and molecular characterization of compost bacteria antagonistic to soilborne plant pathogens.

    PubMed

    Mohamed, Rowida; Groulx, Emma; Defilippi, Stefanie; Erak, Tamara; Tambong, James T; Tweddell, Russell J; Tsopmo, Apollinaire; Avis, Tyler J

    2017-02-08

    Disease suppressive composts have the potential to mitigate the risks associated with chemical pesticides. One of the main characteristics responsible for the suppressive nature of composts is their microbiological populations. In order to gain insight into the determinants responsible for their suppressive effects, composts were assayed (i) to isolate and identify beneficial antagonistic bacteria, (ii) to quantify their antifungal and anti-oomycetal activities, (iii) to extract inhibitory compounds produced by the bacteria, and (iv) to identify antimicrobial lipopeptides produced by these bacteria. The antagonistic bacteria belonged to the Arthrobacter, Pseudomonas, Bacillus, Brevibacillus, Paenibacillus, and Rummeliibacillus genera and had the ability to antagonise the growth of Fusarium sambucinum, Verticillium dahliae, and/or Pythium sulcatum. These bacteria produced antimicrobial compounds that affected the mycelial growth and/or conidial germination of the pathogens. Mass spectrometry analyses showed the presence of various antimicrobial lipopeptides in Bacillus and Bacillus-related spp. extracts, demonstrating that they are, at least in part, responsible for the antagonistic activity of the bacteria. Results from this work provide greater insight into some of the biological, biochemical, and physiological determinants of suppressiveness in composts involved in the control of plant pathogens.

  5. Estimating disturbance effects from military training using developmental instability and physiological measures of plant stress

    USGS Publications Warehouse

    Duda, J.J.; Freeman, D.C.; Brown, M.L.; Graham, J.H.; Krzysik, A.J.; Emlen, J.M.; Zak, J.C.; Kovacic, D.A.

    2004-01-01

    We used developmental instability, water potential, and variable fluorescence to determine if populations of winged sumac (Rhus copallinum) were being negatively effected by military training disturbance. We established nine sites that represented a land-use disturbance gradient with three impact levels (low, medium, and high), the effects mostly due to mechanized infantry training maneuvers. Although mean values of developmental instability, water potential, and variable fluorescence differed significantly among sites, the patterns did not consistently differentiate sites relative to the disturbance gradient. At the population level, some measures of developmental instability and variable fluorescence were positively correlated. All nine sites consisted of habitat mosaics, with the abundance of higher quality habitat patches and canopy gaps closely related to habitat impacts. It may be that R. copallinum is selecting similar micro-environments at all sites and therefore minimizing inter-site variation in stress measures, despite large differences in overall habitat condition. Our results call for caution in developing ecological indicators using the response of physiological and morphological measures from a single plant species. ?? 2003 Elsevier Ltd. All rights reserved.

  6. Physiological and biochemical characterization of Azospirillum brasilense strains commonly used as plant growth-promoting rhizobacteria.

    PubMed

    Di Salvo, Luciana P; Silva, Esdras; Teixeira, Kátia R S; Cote, Rosalba Esquivel; Pereyra, M Alejandra; García de Salamone, Inés E

    2014-12-01

    Azospirillum is a plant growth-promoting rhizobacteria (PGPR) genus vastly studied and utilized as agriculture inoculants. Isolation of new strains under different environmental conditions allows the access to the genetic diversity and improves the success of inoculation procedures. Historically, the isolation of this genus has been performed by the use of some traditional culture media. In this work we characterized the physiology and biochemistry of five different A. brasilense strains, commonly used as cereal inoculants. The aim of this work is to contribute to pose into revision some concepts concerning the most used protocols to isolate and characterize this bacterium. We characterized their growth in different traditional and non-traditional culture media, evaluated some PGPR mechanisms and characterized their profiles of fatty acid methyl esters and carbon-source utilization. This work shows, for the first time, differences in both profiles, and ACC deaminase activity of A. brasilense strains. Also, we show unexpected results obtained in some of the evaluated culture media. Results obtained here and an exhaustive knowledge revision revealed that it is not appropriate to conclude about bacterial species without analyzing several strains. Also, it is necessary to continue developing studies and laboratory techniques to improve the isolation and characterization protocols.

  7. Physiological, structural and molecular traits activated in strawberry plants after inoculation with the plant growth-promoting bacterium Azospirillum brasilense REC3.

    PubMed

    Guerrero-Molina, M F; Lovaisa, N C; Salazar, S M; Martínez-Zamora, M G; Díaz-Ricci, J C; Pedraza, R O

    2015-05-01

    The plant growth-promoting strain REC3 of Azospirillum brasilense, isolated from strawberry roots, prompts growth promotion and systemic protection against anthracnose disease in this crop. Hence, we hypothesised that A. brasilense REC3 can induce different physiological, structural and molecular responses in strawberry plants. Therefore, the aim of this work was to study these traits activated in Azospirillum-colonised strawberry plants, which have not been assessed until now. Healthy, in vitro micropropagated plants were root-inoculated with REC3 under hydroponic conditions; root and leaf tissues were sampled at different times, and oxidative burst, phenolic compound content, malondialdehyde (MDA) concentration, callose deposition, cell wall fortification and gene expression were evaluated. Azospirillum inoculation enhanced levels of soluble phenolic compounds after 12 h post-inoculation (hpi), while amounts of cell wall bound phenolics were similar in inoculated and control plants. Other early responses activated by REC3 (at 24 hpi) were a decline of lipid peroxidation and up-regulation of strawberry genes involved in defence (FaPR1), bacterial recognition (FaFLS2) and H₂O₂ depuration (FaCAT and FaAPXc). The last may explain the apparent absence of oxidative burst in leaves after bacterial inoculation. Also, REC3 inoculation induced delayed structural responses such as callose deposition and cell wall fortification (at 72 hpi). Results showed that A. brasilense REC3 is capable of exerting beneficial effects on strawberry plants, reinforcing their physiological and cellular characteristics, which in turns contribute to improve plant performance.

  8. Differential Response in Plant Taxa Morphology and Physiology During Increases in Late-Quaternary Atmospheric CO2 Concentrations Affect Plant-Climate Interactions.

    NASA Astrophysics Data System (ADS)

    van de Water, P. K.; Barnum, E.

    2004-12-01

    The effects of changing atmospheric CO2 on plant physiology mediate vegetation response to climate change. For example, growth chamber studies on short-lived plants show significant changes in plant morphology and physiological parameters such as changes in biomass and water-use efficiency (WUE; the amount of carbon assimilated to plant water-loss) as atmospheric CO2 concentrations increases from ˜200 p.p.m. to modern concentrations and beyond. Many modern studies show WUE increases linearly with rising atmospheric CO2 meaning that less water is expended for each unit of carbon assimilated. To test for the consistency of these findings with past, long-lived plants and in past communities growing under a similar range of atmospheric CO2 levels, macrofossils of select species were analyzed from packrat (Neotoma sp.) midden chronologies gathered throughout western North America. Measurement of and analysis for the stable isotope content of these macrofossils shows greater morphological and eco-physiological differences between species than expected from study results using growth chambers. For example, isotopic analysis shows long-standing associates, Pinus edulis and Juniperus spp. have significantly different WUE during the transition from the Pleistocene to the Holocene. The WUE in Pinus edulis matches changes in atmospheric CO2 whereas Juniperus spp. does not. Yet over the same period, changes observed in Pinus flexilis needles from trees growing in cooler habitats above the pinyon-juniper woodlands are more similar to Juniperus spp. changes compared against trends in the more closely related Pinus edulis. Morphology changes occurring during this period include increased biomass and reduced stomata. These results show taxonomic differences in the morphological and physiological adaptation to changing CO2 concentrations. These responses need further assessment especially in light of their direct affect on plant-climate interactions.

  9. Psychological and physiological effect in humans of touching plant foliage - using the semantic differential method and cerebral activity as indicators

    PubMed Central

    2013-01-01

    Background Numerous studies have reported on the healing powers of plants and nature, but there have not been so many instances of experimental research. In particular, there are very few psychological and physiological studies using tactile stimuli. This study examines the psychological and physiological effects of touching plant foliage by using an evaluation profile of the subjects’ impressions and investigating cerebral blood flow. Methods The subjects were 14 young Japanese men aged from 21 to 27 years (mean ± standard deviation: 23.6 ± 2.4). With their eyes closed, the subjects touched four different tactile samples including a leaf of natural pothos (Epipremnum aureum). The physiological indices were compared before and after each stimulus. Psychological indices were obtained using a ‘semantic differential’ method. Results The fabric stimulus gave people ‘soft’ and ‘rough’ impressions, ‘kind’, ‘peaceful’ and ‘pleasant’ feelings psychologically, and a sense of physiological calm. On the other hand, the metal stimulus gave people ‘cold’, ‘smooth’ and ‘hard’ impressions and an image of something ‘artificial’. The metal stimulus caused a stress response in human cerebral blood flow although its evaluation in terms of ‘pleasant or unpleasant’ was neutral. There were no remarkable differences between the stimuli of natural and artificial pothos compared with other types of stimulus psychologically. However, only the natural pothos stimulus showed a sense of physiological calm in the same appearance as the fabric stimulus. Conclusions This study shows that people experience an unconscious calming reaction to touching a plant. It is to be concluded that plants are an indispensable element of the human environment. PMID:23587233

  10. Does plasticity in plant physiological traits explain the rapid increase in water use efficiency? An ecohydrological modeling approach

    NASA Astrophysics Data System (ADS)

    Mastrotheodoros, Theodoros; Fatichi, Simone; Pappas, Christoforos; Molnar, Peter; Burlando, Paolo

    2016-04-01

    The rise of atmospheric CO2 concentration is expected to stimulate plant productivity by enhancing photosynthesis and reducing stomatal conductance and thus increasing plant water use efficiency (WUE) worldwide. An analysis of eddy covariance flux tower data from 21 forested ecosystems across the north hemisphere detected an unexpectedly large increase in WUE (Keenan et al, 2013), which was six times larger than the increase found by most previous studies based on controlled experiments (e.g., FACE), leaf-scale analyses, and numerical modelling. This increase could be solely attributed to the increase in atmospheric CO2 since other confounding factors were ruled out. Here, we investigate the potential contribution of plant plasticity, reflected in the temporal adjustment of major plant physiological traits, on changes in WUE using the ecohydrological model Tethys and Chloris (T&C). We hypothesize that the increase in WUE can be attributed to small variations in plant physiological traits, undetectable through observations, eventually triggered by the atmospheric CO2 increase. Data from the 21 sites in the above mentioned study are used to force the model. Simulation results with and without plasticity in the physiological traits (i.e., model parameters in our numerical experiments) are compared with the observed trends in WUE. We test several plant adaptation strategies in being effective in explaining the observed increase in WUE using a multifactorial numerical experiment in which we perturb in a systematic way selected plant parameters. Keenan, T. F., Hollinger, D. Y., Bohrer, G., Dragoni, D., Munger, J. W., Schmid, H. P., and Richardson, A. D. (2013). Increase in forest water-use efficiency as atmospheric carbon dioxide concentrations rise. Nature, 499(7458), 324-7.

  11. FPGA-based smart sensor for drought stress detection in tomato plants using novel physiological variables and discrete wavelet transform.

    PubMed

    Duarte-Galvan, Carlos; Romero-Troncoso, Rene de J; Torres-Pacheco, Irineo; Guevara-Gonzalez, Ramon G; Fernandez-Jaramillo, Arturo A; Contreras-Medina, Luis M; Carrillo-Serrano, Roberto V; Millan-Almaraz, Jesus R

    2014-10-09

    Soil drought represents one of the most dangerous stresses for plants. It impacts the yield and quality of crops, and if it remains undetected for a long time, the entire crop could be lost. However, for some plants a certain amount of drought stress improves specific characteristics. In such cases, a device capable of detecting and quantifying the impact of drought stress in plants is desirable. This article focuses on testing if the monitoring of physiological process through a gas exchange methodology provides enough information to detect drought stress conditions in plants. The experiment consists of using a set of smart sensors based on Field Programmable Gate Arrays (FPGAs) to monitor a group of plants under controlled drought conditions. The main objective was to use different digital signal processing techniques such as the Discrete Wavelet Transform (DWT) to explore the response of plant physiological processes to drought. Also, an index-based methodology was utilized to compensate the spatial variation inside the greenhouse. As a result, differences between treatments were determined to be independent of climate variations inside the greenhouse. Finally, after using the DWT as digital filter, results demonstrated that the proposed system is capable to reject high frequency noise and to detect drought conditions.

  12. FPGA-Based Smart Sensor for Drought Stress Detection in Tomato Plants Using Novel Physiological Variables and Discrete Wavelet Transform

    PubMed Central

    Duarte-Galvan, Carlos; de J. Romero-Troncoso, Rene; Torres-Pacheco, Irineo; Guevara-Gonzalez, Ramon G.; Fernandez-Jaramillo, Arturo A.; Contreras-Medina, Luis M.; Carrillo-Serrano, Roberto V.; Millan-Almaraz, Jesus R.

    2014-01-01

    Soil drought represents one of the most dangerous stresses for plants. It impacts the yield and quality of crops, and if it remains undetected for a long time, the entire crop could be lost. However, for some plants a certain amount of drought stress improves specific characteristics. In such cases, a device capable of detecting and quantifying the impact of drought stress in plants is desirable. This article focuses on testing if the monitoring of physiological process through a gas exchange methodology provides enough information to detect drought stress conditions in plants. The experiment consists of using a set of smart sensors based on Field Programmable Gate Arrays (FPGAs) to monitor a group of plants under controlled drought conditions. The main objective was to use different digital signal processing techniques such as the Discrete Wavelet Transform (DWT) to explore the response of plant physiological processes to drought. Also, an index-based methodology was utilized to compensate the spatial variation inside the greenhouse. As a result, differences between treatments were determined to be independent of climate variations inside the greenhouse. Finally, after using the DWT as digital filter, results demonstrated that the proposed system is capable to reject high frequency noise and to detect drought conditions. PMID:25302811

  13. Physiological Integration Affects Expansion of an Amphibious Clonal Plant from Terrestrial to Cu-Polluted Aquatic Environments.

    PubMed

    Xu, Liang; Zhou, Zhen-Feng

    2017-03-08

    The effects of physiological integration on clonal plants growing in aquatic and terrestrial habitats have been extensively studied, but little is known about the role in the extension of amphibious clonal plants in the heterogeneous aquatic-terrestrial ecotones, especially when the water environments are polluted by heavy metals. Ramets of the amphibious clonal herb Alternanthera philoxeroides were rooted in unpolluted soil and polluted water at three concentrations of Cu. The extension of populations from unpolluted terrestrial to polluted aqueous environments mainly relied on stem elongation rather than production of new ramets. The absorbed Cu in the ramets growing in polluted water could be spread horizontally to other ramets in unpolluted soil via physiological integration and redistributed in different organs. The performances of ramets in both terrestrial and aquatic habitats were negatively correlated with Cu intensities in different organs of plants. It is concluded that physiological integration might lessen the fitness of connected ramets in heterogeneously polluted environments. The mechanical strength of the stems decreased with increasing Cu levels, especially in polluted water. We suggest that, except for direct toxicity to growth and expansion, heavy metal pollution might also increase the mechanical risk in breaking failure of plants.

  14. Physiological Integration Affects Expansion of an Amphibious Clonal Plant from Terrestrial to Cu-Polluted Aquatic Environments

    PubMed Central

    Xu, Liang; Zhou, Zhen-Feng

    2017-01-01

    The effects of physiological integration on clonal plants growing in aquatic and terrestrial habitats have been extensively studied, but little is known about the role in the extension of amphibious clonal plants in the heterogeneous aquatic-terrestrial ecotones, especially when the water environments are polluted by heavy metals. Ramets of the amphibious clonal herb Alternanthera philoxeroides were rooted in unpolluted soil and polluted water at three concentrations of Cu. The extension of populations from unpolluted terrestrial to polluted aqueous environments mainly relied on stem elongation rather than production of new ramets. The absorbed Cu in the ramets growing in polluted water could be spread horizontally to other ramets in unpolluted soil via physiological integration and redistributed in different organs. The performances of ramets in both terrestrial and aquatic habitats were negatively correlated with Cu intensities in different organs of plants. It is concluded that physiological integration might lessen the fitness of connected ramets in heterogeneously polluted environments. The mechanical strength of the stems decreased with increasing Cu levels, especially in polluted water. We suggest that, except for direct toxicity to growth and expansion, heavy metal pollution might also increase the mechanical risk in breaking failure of plants. PMID:28272515

  15. Physiological Integration Affects Expansion of an Amphibious Clonal Plant from Terrestrial to Cu-Polluted Aquatic Environments

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Zhou, Zhen-Feng

    2017-03-01

    The effects of physiological integration on clonal plants growing in aquatic and terrestrial habitats have been extensively studied, but little is known about the role in the extension of amphibious clonal plants in the heterogeneous aquatic-terrestrial ecotones, especially when the water environments are polluted by heavy metals. Ramets of the amphibious clonal herb Alternanthera philoxeroides were rooted in unpolluted soil and polluted water at three concentrations of Cu. The extension of populations from unpolluted terrestrial to polluted aqueous environments mainly relied on stem elongation rather than production of new ramets. The absorbed Cu in the ramets growing in polluted water could be spread horizontally to other ramets in unpolluted soil via physiological integration and redistributed in different organs. The performances of ramets in both terrestrial and aquatic habitats were negatively correlated with Cu intensities in different organs of plants. It is concluded that physiological integration might lessen the fitness of connected ramets in heterogeneously polluted environments. The mechanical strength of the stems decreased with increasing Cu levels, especially in polluted water. We suggest that, except for direct toxicity to growth and expansion, heavy metal pollution might also increase the mechanical risk in breaking failure of plants.

  16. A novel bZIP gene from Tamarix hispida mediates physiological responses to salt stress in tobacco plants.

    PubMed

    Wang, Yucheng; Gao, Caiqiu; Liang, Yenan; Wang, Chao; Yang, Chuanping; Liu, Guifeng

    2010-02-15

    Basic leucine zipper proteins (bZIPs) are transcription factors that bind abscisic acid (ABA)-responsive elements (ABREs) and enable plants to withstand adverse environmental conditions. In the present study, a novel bZIP gene, ThbZIP1 was cloned from Tamarix hispida. Expression studies in T. hispida showed differential regulation of ThbZIP1 in response to treatment with NaCl, polyethylene glycol (PEG) 6000, NaHCO(3), and CdCl(2), suggesting that ThbZIP1 is involved in abiotic stress responses. To identify the physiological responses mediated by ThbZIP1, transgenic tobacco plants overexpressing exogenous ThbZIP1 were generated. Various physiological parameters related to salt stress were measured and compared between transgenic and wild type (WT) plants. Our results indicate that overexpression of ThbZIP1 can enhance the activity of both peroxidase (POD) and superoxide dismutase (SOD), and increase the content of soluble sugars and soluble proteins under salt stress conditions. These results suggest that ThbZIP1 contributes to salt tolerance by mediating signaling through multiple physiological pathways. Furthermore, ThbZIP1 confers stress tolerance to plants by enhancing reactive oxygen species (ROS) scavenging, facilitating the accumulation of compatible osmolytes, and inducing and/or enhancing the biosynthesis of soluble proteins.

  17. Contrasting plant physiological adaptation to climate in the native and introduced range of Hypericum perforatum.

    PubMed

    Maron, John L; Elmendorf, Sarah C; Vilà, Montserrat

    2007-08-01

    How introduced plants, which may be locally adapted to specific climatic conditions in their native range, cope with the new abiotic conditions that they encounter as exotics is not well understood. In particular, it is unclear what role plasticity versus adaptive evolution plays in enabling exotics to persist under new environmental circumstances in the introduced range. We determined the extent to which native and introduced populations of St. John's Wort (Hypericum perforatum) are genetically differentiated with respect to leaf-level morphological and physiological traits that allow plants to tolerate different climatic conditions. In common gardens in Washington and Spain, and in a greenhouse, we examined clinal variation in percent leaf nitrogen and carbon, leaf delta(13)C values (as an integrative measure of water use efficiency), specific leaf area (SLA), root and shoot biomass, root/shoot ratio, total leaf area, and leaf area ratio (LAR). As well, we determined whether native European H. perforatum experienced directional selection on leaf-level traits in the introduced range and we compared, across gardens, levels of plasticity in these traits. In field gardens in both Washington and Spain, native populations formed latitudinal clines in percent leaf N. In the greenhouse, native populations formed latitudinal clines in root and shoot biomass and total leaf area, and in the Washington garden only, native populations also exhibited latitudinal clines in percent leaf C and leaf delta(13)C. Traits that failed to show consistent latitudinal clines instead exhibited significant phenotypic plasticity. Introduced St. John's Wort populations also formed significant or marginally significant latitudinal clines in percent leaf N in Washington and Spain, percent leaf C in Washington, and in root biomass and total leaf area in the greenhouse. In the Washington common garden, there was strong directional selection among European populations for higher percent leaf N and

  18. Morphological and Physiological Responses of Cotton (Gossypium hirsutum L.) Plants to Salinity

    PubMed Central

    Zhang, Lei; Ma, Huijuan; Chen, Tingting; Pen, Jun; Yu, Shuxun; Zhao, Xinhua

    2014-01-01

    Salinization usually plays a primary role in soil degradation, which consequently reduces agricultural productivity. In this study, the effects of salinity on growth parameters, ion, chlorophyll, and proline content, photosynthesis, antioxidant enzyme activities, and lipid peroxidation of two cotton cultivars, [CCRI-79 (salt tolerant) and Simian 3 (salt sensitive)], were evaluated. Salinity was investigated at 0 mM, 80 mM, 160 mM, and 240 mM NaCl for 7 days. Salinity induced morphological and physiological changes, including a reduction in the dry weight of leaves and roots, root length, root volume, average root diameter, chlorophyll and proline contents, net photosynthesis and stomatal conductance. In addition, salinity caused ion imbalance in plants as shown by higher Na+ and Cl− contents and lower K+, Ca2+, and Mg2+ concentrations. Ion imbalance was more pronounced in CCRI-79 than in Simian3. In the leaves and roots of the salt-tolerant cultivar CCRI-79, increasing levels of salinity increased the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), but reduced catalase (CAT) activity. The activities of SOD, CAT, APX, and GR in the leaves and roots of CCRI-79 were higher than those in Simian 3. CAT and APX showed the greatest H2O2 scavenging activity in both leaves and roots. Moreover, CAT and APX activities in conjunction with SOD seem to play an essential protective role in the scavenging process. These results indicate that CCRI-79 has a more effective protection mechanism and mitigated oxidative stress and lipid peroxidation by maintaining higher antioxidant activities than those in Simian 3. Overall, the chlorophyll a, chlorophyll b, and Chl (a+b) contents, net photosynthetic rate and stomatal conductance, SOD, CAT, APX, and GR activities showed the most significant variation between the two cotton cultivars. PMID:25391141

  19. Morphological and physiological responses of cotton (Gossypium hirsutum L.) plants to salinity.

    PubMed

    Zhang, Lei; Ma, Huijuan; Chen, Tingting; Pen, Jun; Yu, Shuxun; Zhao, Xinhua

    2014-01-01

    Salinization usually plays a primary role in soil degradation, which consequently reduces agricultural productivity. In this study, the effects of salinity on growth parameters, ion, chlorophyll, and proline content, photosynthesis, antioxidant enzyme activities, and lipid peroxidation of two cotton cultivars, [CCRI-79 (salt tolerant) and Simian 3 (salt sensitive)], were evaluated. Salinity was investigated at 0 mM, 80 mM, 160 mM, and 240 mM NaCl for 7 days. Salinity induced morphological and physiological changes, including a reduction in the dry weight of leaves and roots, root length, root volume, average root diameter, chlorophyll and proline contents, net photosynthesis and stomatal conductance. In addition, salinity caused ion imbalance in plants as shown by higher Na+ and Cl- contents and lower K+, Ca2+, and Mg2+ concentrations. Ion imbalance was more pronounced in CCRI-79 than in Simian3. In the leaves and roots of the salt-tolerant cultivar CCRI-79, increasing levels of salinity increased the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), but reduced catalase (CAT) activity. The activities of SOD, CAT, APX, and GR in the leaves and roots of CCRI-79 were higher than those in Simian 3. CAT and APX showed the greatest H2O2 scavenging activity in both leaves and roots. Moreover, CAT and APX activities in conjunction with SOD seem to play an essential protective role in the scavenging process. These results indicate that CCRI-79 has a more effective protection mechanism and mitigated oxidative stress and lipid peroxidation by maintaining higher antioxidant activities than those in Simian 3. Overall, the chlorophyll a, chlorophyll b, and Chl (a+b) contents, net photosynthetic rate and stomatal conductance, SOD, CAT, APX, and GR activities showed the most significant variation between the two cotton cultivars.

  20. Evaluating the influence of plant-specific physiological parameterizations on the partitioning of land surface energy fluxes

    NASA Astrophysics Data System (ADS)

    Sulis, Mauro; Langensiepen, Matthias; Shrestha, Prabhakar; Schickling, Anke; Simmer, Clemens; Kollet, Stefan

    2015-04-01

    Vegetation has a significant influence on the partitioning of radiative forcing, the spatial and temporal variability of soil water and soil temperature. Therefore plant physiological properties play a key role in mediating and amplifying interactions and feedback mechanisms in the soil-vegetation-atmosphere continuum. Because of the direct impact on latent heat fluxes, these properties may also influence weather generating processes, such as the evolution of the atmospheric boundary layer (ABL). In land surface models, plant physiological properties are usually obtained from literature synthesis by unifying several plant/crop species in predefined vegetation classes. In this work, crop-specific physiological characteristics, retrieved from detailed field measurements, are included in the bio-physical parameterization of the Community Land Model (CLM), which is a component of the Terrestrial Systems Modeling Platform (TerrSysMP). The measured set of parameters for two typical European mid-latitudinal crops (sugar beet and winter wheat) is validated using eddy covariance measurements (sensible heat and latent heat) over multiple years from three measurement sites located in the North Rhine-Westphalia region, Germany. We found clear improvements of CLM simulations, when using the crop-specific physiological characteristics of the plants instead of the generic crop type when compared to the measurements. In particular, the increase of latent heat fluxes in conjunction with decreased sensible heat fluxes as simulated by the two new crop-specific parameter sets leads to an improved quantification of the diurnal energy partitioning. These findings are cross-validated using estimates of gross primary production extracted from net ecosystem exchange measurements. This independent analysis reveals that the better agreement between observed and simulated latent heat using the plant-specific physiological properties largely stems from an improved simulation of the

  1. Evaluating the physiological state of maize (Zea mays L.) plants by direct-injection electrospray mass spectrometry (DIESI-MS).

    PubMed

    García-Flores, Martín; Juárez-Colunga, Sheila; Montero-Vargas, Josaphat Miguel; López-Arciniega, Janet Ana Isabel; Chagolla, Alicia; Tiessen, Axel; Winkler, Robert

    2012-06-01

    Climatic change is an increasing challenge for agriculture that is driving the development of suitable crops in order to ensure supply for both human nutrition and animal feed. In this context, it is increasingly important to understand the biochemical responses of cells to environmental cues at the whole system level, an aim that is being brought closer by advances in high throughput, cost-efficient plant metabolomics. To support molecular breeding activities, we have assessed the economic, technical and statistical feasibility of using direct mass spectrometry methods to evaluate the physiological state of maize (Zea mays L.) plants grown under different stress conditions.

  2. Physiological relaxation induced by horticultural activity: transplanting work using flowering plants

    PubMed Central

    2013-01-01

    Background Despite increasing attention and a growing volume of research data, little physiological evidence is available on the benefits of horticultural activity and the different effects on individuals. Therefore, the aim of the present study was to investigate the physiological effects of horticultural activity and to examine how differences in personality alter these effects. Results The effects of transplanting real flowers (horticultural activity) and handling artificial flowers (control activity) on human physiological activity were compared. On the first day, eight participants engaged in horticultural activity and another eight in the control activity. On the second day, participants switched roles. Participants’ physiological conditions during each activity were assessed by measuring the heart rate and heart rate variability (HRV). Psychological responses, which were measured using a semantic differential rating scale, showed that the horticultural activity promoted comfortable, soothed, and natural feelings, compared to the control activity. Analysis of physiological responses using two-way repeated measures analysis of variance (ANOVA) revealed that sympathetic nervous activity significantly decreased in the late time period (11 to 15 minutes) of horticultural activity only in the type A group. Conclusions This study supports the fact that the horticultural activity can enhance psychological and physiological relaxation effects, although these physiological effects can differ among individuals with different personalities. PMID:24112302

  3. Work physiology of operating personnel at power plants in arid regions

    SciTech Connect

    Mommadov, I.M.; Grigoryan, A.G.; Tupikova, G.A.

    1985-02-01

    Various physiological parameters were observed in July and August when the ambient temperature exceeded 40 C on a cohort of 20 40-year old, clinically healthy, males. Evaluation of the functional status of the different physiological systems demonstrates that heat is the key factor affecting physiological well-being. The combination of heat and performance requirements placed considerable stress on the homeostatic mechanisms, as reflected in greater energy expenditures for task accomplishment and earlier onset of fatigue. Physiological reserves are directed at maintenance of body temperature balance at the expense of muscular performance under the climatic conditions prevalent in the region. To ensure optimum job performance, exposure to high temperatures must be limited and insolated, air-conditioned, rest facilities must be provided. Workers must have appropriate nutrition, clothing, and vitamin supplements, physical conditioning, and other medical measures that enhance adaptation to arid climates.

  4. Paclobutrazol induces tolerance in tomato to deficit irrigation through diversified effects on plant morphology, physiology and metabolism.

    PubMed

    Pal, Sikander; Zhao, Jiangsan; Khan, Asif; Yadav, Narendra Singh; Batushansky, Albert; Barak, Simon; Rewald, Boris; Fait, Aaron; Lazarovitch, Naftali; Rachmilevitch, Shimon

    2016-12-22

    Dwindling water resources combined with meeting the demands for food security require maximizing water use efficiency (WUE) both in rainfed and irrigated agriculture. In this regard, deficit irrigation (DI), defined as the administration of water below full crop-water requirements (evapotranspiration), is a valuable practice to contain irrigation water use. In this study, the mechanism of paclobutrazol (Pbz)-mediated improvement in tolerance to water deficit in tomato was thoroughly investigated. Tomato plants were subjected to normal irrigated and deficit irrigated conditions plus Pbz application (0.8 and 1.6 ppm). A comprehensive morpho-physiological, metabolomics and molecular analysis was undertaken. Findings revealed that Pbz application reduced plant height, improved stem diameter and leaf number, altered root architecture, enhanced photosynthetic rates and WUE of tomato plants under deficit irrigation. Pbz differentially induced expression of genes and accumulation of metabolites of the tricarboxylic acid (TCA) cycle, γ-aminobutyric acid (GABA-shunt pathway), glutathione ascorbate (GSH-ASC)-cycle, cell wall and sugar metabolism, abscisic acid (ABA), spermidine (Spd) content and expression of an aquaporin (AP) protein under deficit irrigation. Our results suggest that Pbz application could significantly improve tolerance in tomato plants under limited water availability through selective changes in morpho-physiology and induction of stress-related molecular processes.

  5. Paclobutrazol induces tolerance in tomato to deficit irrigation through diversified effects on plant morphology, physiology and metabolism

    PubMed Central

    Pal, Sikander; Zhao, Jiangsan; Khan, Asif; Yadav, Narendra Singh; Batushansky, Albert; Barak, Simon; Rewald, Boris; Fait, Aaron; Lazarovitch, Naftali; Rachmilevitch, Shimon

    2016-01-01

    Dwindling water resources combined with meeting the demands for food security require maximizing water use efficiency (WUE) both in rainfed and irrigated agriculture. In this regard, deficit irrigation (DI), defined as the administration of water below full crop-water requirements (evapotranspiration), is a valuable practice to contain irrigation water use. In this study, the mechanism of paclobutrazol (Pbz)-mediated improvement in tolerance to water deficit in tomato was thoroughly investigated. Tomato plants were subjected to normal irrigated and deficit irrigated conditions plus Pbz application (0.8 and 1.6 ppm). A comprehensive morpho-physiological, metabolomics and molecular analysis was undertaken. Findings revealed that Pbz application reduced plant height, improved stem diameter and leaf number, altered root architecture, enhanced photosynthetic rates and WUE of tomato plants under deficit irrigation. Pbz differentially induced expression of genes and accumulation of metabolites of the tricarboxylic acid (TCA) cycle, γ-aminobutyric acid (GABA-shunt pathway), glutathione ascorbate (GSH-ASC)-cycle, cell wall and sugar metabolism, abscisic acid (ABA), spermidine (Spd) content and expression of an aquaporin (AP) protein under deficit irrigation. Our results suggest that Pbz application could significantly improve tolerance in tomato plants under limited water availability through selective changes in morpho-physiology and induction of stress-related molecular processes. PMID:28004823

  6. Modifications of Morphometrical and Physiological Parameters of Pepper Plants Grown on Artificial Nutrient Medium for Experiments in Spaceflight

    NASA Astrophysics Data System (ADS)

    Nechitailo, Galina S.

    2016-07-01

    MODIFICATIONS OF MORPHOMETRICAL AND PHYSIOLOGICAL PARAMETERS OF PEPPER PLANTS GROWN ON ARTIFICIAL NUTRIENT MEDIUM FOR EXPERIMENTS IN SPACEFLIGHT Lui Min*, Zhao Hui*, Chen Yu*, Lu Jinying*, Li Huasheng*, Sun Qiao*, Nechitajlo G.S.**, Glushchenko N.N.*** *Shenzhou Space Biotechnology Group, China Academy of Space Technology (CAST), **Emanuel Institute of Biochemical Physics of Russian Academy of Sciences (IBCP RAS) mail: spacemal@mail.ru ***V.L. Talrose Institute for Energy Problems of Chemical Physics of Russian Academy of Science (INEPCP RAS) mail: nnglu@ mail.ru In circumstances of space flights, long residence of the staff at space stations and space settlements an optimal engineering system of the life-support allowing to solve a number of technical and psychological problems for successful work and a life of cosmonauts, researchers, etc. is important and prime. In this respect it is necessary to consider growing plants on board of spacecraft as one of the units in a life-support system. It is feasible due to modern development of biotechnologies in growing plants allowing us to receive materials with new improved properties. Thus, a composition and ratio of components of nutrient medium can considerably influence on plants properties. We have developed the nutrient medium in which essential metals such as iron, zinc, copper were added in an electroneutral state in the form of nanoparticles instead of sulfates or other salts of the same metals. Such replacement is appropriate through unique nanoparticles properties: metal nanoparticles are less toxic than their corresponding ionic forms; nanoparticles produce a prolonged effect, serving as a depot for elements in an organism; nanoparticles introduced in biotic doses stimulate the metabolic processes of the organism; nanoparticles effect is multifunctional. Pepper strain LJ-king was used for growing on a nutrient medium with ferrous, zinc, copper nanoparticles in different concentrations. Pepper plants grown on

  7. Soil organic matter influences cerium translocation and physiological processes in kidney bean plants exposed to cerium oxide nanoparticles.

    PubMed

    Majumdar, Sanghamitra; Peralta-Videa, Jose R; Trujillo-Reyes, Jesica; Sun, Youping; Barrios, Ana C; Niu, Genhua; Margez, Juan P Flores-; Gardea-Torresdey, Jorge L

    2016-11-01

    Soil organic matter plays a major role in determining the fate of the engineered nanomaterials (ENMs) in the soil matrix and effects on the residing plants. In this study, kidney bean plants were grown in soils varying in organic matter content and amended with 0-500mg/kg cerium oxide nanoparticles (nano-CeO2) under greenhouse condition. After 52days of exposure, cerium accumulation in tissues, plant growth and physiological parameters including photosynthetic pigments (chlorophylls and carotenoids), net photosynthesis rate, transpiration rate, and stomatal conductance were recorded. Additionally, catalase and ascorbate peroxidase activities were measured to evaluate oxidative stress in the tissues. The translocation factor of cerium in the nano-CeO2 exposed plants grown in organic matter enriched soil (OMES) was twice as the plants grown in low organic matter soil (LOMS). Although the leaf cover area increased by 65-111% with increasing nano-CeO2 concentration in LOMS, the effect on the physiological processes were inconsequential. In OMES leaves, exposure to 62.5-250mg/kg nano-CeO2 led to an enhancement in the transpiration rate and stomatal conductance, but to a simultaneous decrease in carotenoid contents by 25-28%. Chlorophyll a in the OMES leaves also decreased by 27 and 18% on exposure to 125 and 250mg/kg nano-CeO2. In addition, catalase activity increased in LOMS stems, and ascorbate peroxidase increased in OMES leaves of nano-CeO2 exposed plants, with respect to control. Thus, this study provides clear evidence that the properties of the complex soil matrix play decisive roles in determining the fate, bioavailability, and biological transport of ENMs in the environment.

  8. Morphological and Physiological Responses to Sediment Type and Light Availability in Roots of the Submerged Plant Myriophyllum spicatum

    PubMed Central

    Xie, Yonghong; Luo, Wenbo; Ren, Bo; Li, Feng

    2007-01-01

    Background and Aims Both sediment and light are essential factors regulating the growth of submerged macrophytes, but the role of these two factors in regulating root morphology and physiology is far from clear. The responses of root morphology and physiology to sediment type and light availability in the submerged plant Myriophyllum spicatum were studied and the hypothesis was tested that a trade-off exists in root growth strategy between internal aeration and nutrient acquisition. Method Plants were grown on two types of sediment (fertile mud and an infertile mixture of mud and sandy loam) and under three levels of light availability (600, 80 and 20 µ mol m−2 s−1) in a greenhouse. Key Results The significantly higher alcohol dehydrogenase (ADH) activity in root tissues indicated that oxygen deficiency existed in the plants growing in fertile mud and low (or high) light environments. Significantly, low plant N and P concentrations indicated that nutrient deficiency existed in the mixed sediment and high light environment. As a response to anoxia, plants did not change the porosity of the main roots. The effect of sediment type on root morphology was insignificant under higher light environments, whereas root diameter generally decreased but specific root length (SRL) increased with decreasing light availability. Both low light and fertile mud jointly led to lack of second-order laterals. More biomass was allocated to lateral roots in infertile environments, whereas mass fractions of laterals were lower in low light and mud environments. Conclusions These data indicate that this plant can achieve the trade-off between internal aeration and nutrient acquisition by adjusting the structure of the root system and the pattern of biomass allocation to different root orders rather than root morphology and root porosity. PMID:17959731

  9. Shared and unique responses of plants to multiple individual stresses and stress combinations: physiological and molecular mechanisms

    PubMed Central

    Pandey, Prachi; Ramegowda, Venkategowda; Senthil-Kumar, Muthappa

    2015-01-01

    In field conditions, plants are often simultaneously exposed to multiple biotic and abiotic stresses resulting in substantial yield loss. Plants have evolved various physiological and molecular adaptations to protect themselves under stress combinations. Emerging evidences suggest that plant responses to a combination of stresses are unique from individual stress responses. In addition, plants exhibit shared responses which are common to individual stresses and stress combination. In this review, we provide an update on the current understanding of both unique and shared responses. Specific focus of this review is on heat–drought stress as a major abiotic stress combination and, drought–pathogen and heat–pathogen as examples of abiotic–biotic stress combinations. We also comprehend the current understanding of molecular mechanisms of cross talk in relation to shared and unique molecular responses for plant survival under stress combinations. Thus, the knowledge of shared responses of plants from individual stress studies and stress combinations can be utilized to develop varieties with broad spectrum stress tolerance. PMID:26442037

  10. The fascinating facets of plant selenium accumulation - biochemistry, physiology, evolution and ecology.

    PubMed

    Schiavon, Michela; Pilon-Smits, Elizabeth A H

    2017-03-01

    Contents 1582 I. 1582 II. 1583 III. 1588 IV. 1590 V. 1592 1592 References 1592 SUMMARY: The importance of selenium (Se) for medicine, industry and the environment is increasingly apparent. Se is essential for many species, including humans, but toxic at elevated concentrations. Plant Se accumulation and volatilization may be applied in crop biofortification and phytoremediation. Topics covered here include beneficial and toxic effects of Se on plants, mechanisms of Se accumulation and tolerance in plants and algae, Se hyperaccumulation, and ecological and evolutionary aspects of these processes. Plant species differ in the concentration and forms of Se accumulated, Se partitioning at the whole-plant and tissue levels, and the capacity to distinguish Se from sulfur. Mechanisms of Se hyperaccumulation and its adaptive significance appear to involve constitutive up-regulation of sulfate/selenate uptake and assimilation, associated with elevated concentrations of defense-related hormones. Hyperaccumulation has evolved independently in at least three plant families, probably as an elemental defense mechanism and perhaps mediating elemental allelopathy. Elevated plant Se protects plants from generalist herbivores and pathogens, but also gives rise to the evolution of Se-resistant specialists. Plant Se accumulation affects ecological interactions with herbivores, pollinators, neighboring plants, and microbes. Hyperaccumulation tends to negatively affect Se-sensitive ecological partners while facilitating Se-resistant partners, potentially affecting species composition and Se cycling in seleniferous ecosystems.

  11. Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses

    NASA Astrophysics Data System (ADS)

    Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

    2013-12-01

    In terrestrial ecosystems, plant photosynthesis occurs at the expense of water losses through stomata, thus creating an inherent hydrologic constrain to carbon (C) gains and productivity. While such a constraint cannot be overcome, evolution has led to a number of adaptations that allow plants to thrive under highly variable and often limiting water availability. It may be hypothesized that these adaptations are optimal and allow maximum C gain for a given water availability. A corollary hypothesis is that these adaptations manifest themselves as coordination between the leaf photosynthetic machinery and the plant hydraulic system. This coordination leads to functional relations between the mean hydrologic state, plant hydraulic traits, and photosynthetic parameters that can be used as bridge across temporal scales. Here, optimality theories describing the behavior of stomata and plant morphological features in a fluctuating soil moisture environment are proposed. The overarching goal is to explain observed global patterns of plant water use and their ecological and biogeochemical consequences. The problem is initially framed as an optimal control problem of stomatal closure during drought of a given duration, where maximizing the total photosynthesis under limited and diminishing water availability is the objective function. Analytical solutions show that commonly used transpiration models (in which stomatal conductance is assumed to depend on soil moisture) are particular solutions emerging from the optimal control problem. Relations between stomatal conductance, vapor pressure deficit, and atmospheric CO2 are also obtained without any a priori assumptions under this framework. Second, the temporal scales of the model are expanded by explicitly considering the stochasticity of rainfall. In this context, the optimal control problem becomes a maximization problem for the mean photosynthetic rate. Results show that to achieve maximum C gains under these

  12. Physiological response and sulfur metabolism of the V. dahliae-infected tomato plants in tomato/potato onion companion cropping

    PubMed Central

    Fu, Xuepeng; Li, Chunxia; Zhou, Xingang; Liu, Shouwei; Wu, Fengzhi

    2016-01-01

    Companion cropping with potato onions (Allium cepa var. agrogatum Don.) can enhance the disease resistance of tomato plants (Solanum lycopersicum) to Verticillium dahliae infection by increasing the expressions of genes related to disease resistance. However, it is not clear how tomato plants physiologically respond to V. dahliae infection and what roles sulfur plays in the disease-resistance. Pot experiments were performed to examine changes in the physiology and sulfur metabolism of tomato roots infected by V. dahliae under the companion cropping (tomato/potato onion). The results showed that the companion cropping increased the content of total phenol, lignin and glutathione and increased the activities of peroxidase, polyphenol oxidase and phenylalanine ammonia lyase in the roots of tomato plants. RNA-seq analysis showed that the expressions of genes involved in sulfur uptake and assimilation, and the formation of sulfur-containing defense compounds (SDCs) were up-regulated in the V. dahlia-infected tomatoes in the companion cropping. In addition, the interactions among tomato, potato onion and V. dahliae induced the expression of the high- affinity sulfate transporter gene in the tomato roots. These results suggest that sulfur may play important roles in tomato disease resistance against V. dahliae. PMID:27808257

  13. Ascending migration of endophytic rhizobia, from roots to leaves, inside rice plants and assessment of benefits to rice growth physiology.

    PubMed

    Chi, Feng; Shen, Shi-Hua; Cheng, Hai-Ping; Jing, Yu-Xiang; Yanni, Youssef G; Dazzo, Frank B

    2005-11-01

    Rhizobia, the root-nodule endosymbionts of leguminous plants, also form natural endophytic associations with roots of important cereal plants. Despite its widespread occurrence, much remains unknown about colonization of cereals by rhizobia. We examined the infection, dissemination, and colonization of healthy rice plant tissues by four species of gfp-tagged rhizobia and their influence on the growth physiology of rice. The results indicated a dynamic infection process beginning with surface colonization of the rhizoplane (especially at lateral root emergence), followed by endophytic colonization within roots, and then ascending endophytic migration into the stem base, leaf sheath, and leaves where they developed high populations. In situ CMEIAS image analysis indicated local endophytic population densities reaching as high as 9 x 10(10) rhizobia per cm3 of infected host tissues, whereas plating experiments indicated rapid, transient or persistent growth depending on the rhizobial strain and rice tissue examined. Rice plants inoculated with certain test strains of gfp-tagged rhizobia produced significantly higher root and shoot biomass; increased their photosynthetic rate, stomatal conductance, transpiration velocity, water utilization efficiency, and flag leaf area (considered to possess the highest photosynthetic activity); and accumulated higher levels of indoleacetic acid and gibberellin growth-regulating phytohormones. Considered collectively, the results indicate that this endophytic plant-bacterium association is far more inclusive, invasive, and dynamic than previously thought, including dissemination in both below-ground and above-ground tissues and enhancement of growth physiology by several rhizobial species, therefore heightening its interest and potential value as a biofertilizer strategy for sustainable agriculture to produce the world's most important cereal crops.

  14. Physiological and molecular implications of plant polyamine metabolism during biotic interactions

    PubMed Central

    Jiménez-Bremont, Juan F.; Marina, María; Guerrero-González, María de la Luz; Rossi, Franco R.; Sánchez-Rangel, Diana; Rodríguez-Kessler, Margarita; Ruiz, Oscar A.; Gárriz, Andrés

    2014-01-01

    During ontogeny, plants interact with a wide variety of microorganisms. The association with mutualistic microbes results in benefits for the plant. By contrast, pathogens may cause a remarkable impairment of plant growth and development. Both types of plant–microbe interactions provoke notable changes in the polyamine (PA) metabolism of the host and/or the microbe, being each interaction a complex and dynamic process. It has been well documented that the levels of free and conjugated PAs undergo profound changes in plant tissues during the interaction with microorganisms. In general, this is correlated with a precise and coordinated regulation of PA biosynthetic and catabolic enzymes. Interestingly, some evidence suggests that the relative importance of these metabolic pathways may depend on the nature of the microorganism, a concept that stems from the fact that these amines mediate the activation of plant defense mechanisms. This effect is mediated mostly through PA oxidation, even though part of the response is activated by non-oxidized PAs. In the last years, a great deal of effort has been devoted to profile plant gene expression following microorganism recognition. In addition, the phenotypes of transgenic and mutant plants in PA metabolism genes have been assessed. In this review, we integrate the current knowledge on this field and analyze the possible roles of these amines during the interaction of plants with microbes. PMID:24672533

  15. Physiology and toxicology of hormone-disrupting chemicals in higher plants.

    PubMed

    Couée, Ivan; Serra, Anne-Antonella; Ramel, Fanny; Gouesbet, Gwenola; Sulmon, Cécile

    2013-06-01

    Higher plants are exposed to natural environmental organic chemicals, associated with plant-environment interactions, and xenobiotic environmental organic chemicals, associated with anthropogenic activities. The effects of these chemicals result not only from interaction with metabolic targets, but also from interaction with the complex regulatory networks of hormone signaling. Purpose-designed plant hormone analogues thus show extensive signaling effects on gene regulation and are as such important for understanding plant hormone mechanisms and for manipulating plant growth and development. Some natural environmental chemicals also act on plants through interference with the perception and transduction of endogenous hormone signals. In a number of cases, bioactive xenobiotics, including herbicides that have been designed to affect specific metabolic targets, show extensive gene regulation effects, which are more in accordance with signaling effects than with consequences of metabolic effects. Some of these effects could be due to structural analogies with plant hormones or to interference with hormone metabolism, thus resulting in situations of hormone disruption similar to animal cell endocrine disruption by xenobiotics. These hormone-disrupting effects can be superimposed on parallel metabolic effects, thus indicating that toxicological characterisation of xenobiotics must take into consideration the whole range of signaling and metabolic effects. Hormone-disruptive signaling effects probably predominate when xenobiotic concentrations are low, as occurs in situations of residual low-level pollutions. These hormone-disruptive effects in plants may thus be of importance for understanding cryptic effects of low-dosage xenobiotics, as well as the interactive effects of mixtures of xenobiotic pollutants.

  16. Physiological effects of magnetite (Fe3O4) nanoparticles on perennial ryegrass (Lolium perenne L.) and pumpkin (Cucurbita mixta) plants.

    PubMed

    Wang, Huanhua; Kou, Xiaoming; Pei, Zhiguo; Xiao, John Q; Shan, Xiaoquan; Xing, Baoshan

    2011-03-01

    To date, knowledge gaps and associated uncertainties remain unaddressed on the effects of nanoparticles (NPs) on plants. This study was focused on revealing some of the physiological effects of magnetite (Fe(3)O(4)) NPs on perennial ryegrass (Lolium perenne L.) and pumpkin (Cucurbita mixta cv. white cushaw) plants under hydroponic conditions. This study for the first time reports that Fe(3)O(4) NPs often induced more oxidative stress than Fe(3)O(4) bulk particles in the ryegrass and pumpkin roots and shoots as indicated by significantly increased: (i) superoxide dismutase and catalase enzyme activities, and (ii) lipid peroxidation. However, tested Fe(3)O(4) NPs appear unable to be translocated in the ryegrass and pumpkin plants. This was supported by the following data: (i) No magnetization was detected in the shoots of either plant treated with 30, 100 and 500 mg l(-1) Fe(3)O(4) NPs; (ii) Fe K-edge X-ray absorption spectroscopic study confirmed that the coordination environment of Fe in these plant shoots was similar to that of Fe-citrate complexes, but not to that of Fe(3)O(4) NPs; and (iii) total Fe content in the ryegrass and pumpkin shoots treated with Fe(3)O(4) NPs was not significantly increased compared to that in the control shoots.

  17. Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1.

    PubMed

    Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

    2014-04-01

    The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice. And growth-promoting responses were determined mainly as an increase of chlorophyll a/b ratio, which indicates a potential elevation of photosynthesis rates, and enhancements of photosynthesis and EXP expression in the three plant species. In Arabidopsis, Hpa1-induced growth-promoting responses were partially compromised by a defect in ethylene perception or gibberellin biosynthesis. In tomato and rice, compromises of Hpa1-induced growth-promoting responses were caused by a pharmacological treatment with an ethylene perception inhibitor or a gibberellin biosynthesis inhibitor. In the three plant species, moreover, Hpa1-induced growth-promoting responses were significantly impaired, but not totally eliminated, by abolishing ethylene perception or gibberellin synthesis. However, simultaneous nullifications in both ethylene perception and gibberellin biosynthesis almost canceled the full effects of Hpa1 on plant growth, photosynthesis, and EXP2 expression. Theses results suggest that ethylene and gibberellin coregulate Hpa1-induced plant growth enhancement and associated physiological and molecular responses.

  18. Plant physiological response of strawberry fruit to chlorine dioxide gas treatment during postharvest storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorine dioxide, a strong oxidizing and sanitizing agent, is used as a postharvest sanitizer for fruits and vegetables and generally applied on a packing line using a chlorine dioxide generator. The objective of this research was to study the physiological responses of strawberries to ClO2 when app...

  19. Activators of Biochemical and Physiological Processes in Plants Based on Fine Humic Acids

    NASA Astrophysics Data System (ADS)

    Churilov, G.; Polishuk, S.; Kutskir, M.; Churilov, D.; Borychev, S.

    2015-11-01

    This article describes the application of ultrafine humic acids as growth promoters and development of crops, for example corn. During the study we determined the optimal concentration of humic acids in ultrafine state for presowing treatment of seeds of maize. An analysis of laboratory and field tests was presented. We showed the relationship between physiological changes and biochemical processes.

  20. Substantial roles of hexokinase and fructokinase in the effects of sugars on plant physiology and development.

    PubMed

    Granot, David; Kelly, Gilor; Stein, Ofer; David-Schwartz, Rakefet

    2014-03-01

    The basic requirements for plant growth are light, CO2, water, and minerals. However, the absorption and utilization of each of these requires investment on the part of the plant. The primary products of plants are sugars, and the hexose sugars glucose and fructose are the raw material for most of the metabolic pathways and organic matter in plants. To be metabolized, hexose sugars must first be phosphorylated. Only two families of enzymes capable of catalysing the essential irreversible phosphorylation of glucose and fructose have been identified in plants, hexokinases (HXKs) and fructokinases (FRKs). These hexose-phosphorylating enzymes appear to coordinate sugar production with the abilities to absorb light, CO2, water, and minerals. This review describes the long- and short-term effects mediated by HXK and FRK in various tissues, as well as the role of these enzymes in the coordination of sugar production with the absorption of light, CO2, water, and minerals.

  1. Shifting effects of physiological integration on performance of a clonal plant during submergence and de-submergence

    PubMed Central

    Luo, Fang-Li; Chen, Yue; Huang, Lin; Wang, Ao; Zhang, Ming-Xiang; Yu, Fei-Hai

    2014-01-01

    Background and Aims Submergence and de-submergence are common phenomena encountered by riparian plants due to water level fluctuations, but little is known about the role of physiological integration in clonal plants (resource sharing between interconnected ramets) in their adaptation to such events. Using Alternanthera philoxeroides (alligator weed) as an example, this study tested the hypotheses that physiological integration will improve growth and photosynthetic capacity of submerged ramets during submergence and will promote their recovery following de-submergence. Methods Connected clones of A. philoxeroides, each consisting of two ramet systems and a stolon internode connecting them, were grown under control (both ramet systems untreated), half-submerged (one ramet system submerged and the other not submerged), fully submerged (both ramet systems submerged), half-shaded (one ramet system shaded and the other not shaded) and full-shaded (both ramet systems shaded) conditions for 30 d and then de-submerged/de-shaded for 20 d. The submerged plants were also shaded to very low light intensities, mimicking typical conditions in turbid floodwater. Key Results After 30 d of submergence, connections between submerged and non-submerged ramets significantly increased growth and carbohydrate accumulation of the submerged ramets, but decreased the growth of the non-submerged ramets. After 20 d of de-submergence, connections did not significantly affect the growth of either de-submerged or non-submerged ramets, but de-submerged ramets had high soluble sugar concentrations, suggesting high metabolic activities. The shift from significant effects of integration on both submerged and non-submerged ramets during the submergence period to little effect during the de-submergence period was due to the quick recovery of growth and photosynthesis. The effects of physiological integration were not found to be any stronger under submergence/de-submergence than under shading

  2. Influence of Environmental Changes on Physiology and Development of Polar Vascular Plants

    NASA Astrophysics Data System (ADS)

    Giełwanowska, Irena; Pastorczyk, Marta; Kellmann-Sopyła, Wioleta

    2011-01-01

    Polar vascular plants native to the Arctic and the Antarctic geobotanical zone have been growing and reproducing effectively under difficult environmental conditions, colonizing frozen ground areas formerly covered by ice. Our macroscopic observations and microscopic studies conducted by means of a light microscope (LM) and transmission electron microscope (TEM) concerning the anatomical and ultrastructural observations of vegetative and generative tissue in Cerastium arcticum, Colobanthus quitensis, Silene involucrata, plants from Caryophyllaceae and Deschampsia antarctica, Poa annua and Poa arctica, from Poaceae family. In the studies, special attention was paid to plants coming from diversity habitats where stress factors operated with clearly different intensity. In all examinations plants, differences in anatomy were considerable. In Deschampsia antarctica the adaxial epidermis of hairgrass leaves from a humid microhabitat, bulliform cells differentiated. Mesophyll was composed of cells of irregular shapes and resembled aerenchyma. The ultrastructural observations of mesophyll in all plants showed tight adherence of chloroplasts, mitochondria and peroxisomes, surface deformations of these organelles and formation of characteristic outgrowths and pocket concavities filled with cytoplasm with vesicles and organelles by chloroplasts. In reproduction biology of examined Caryophyllaceae and Poaceae plants growing in natural conditions, in the Arctic and in the Antarctic, and in a greenhouse in Olsztyn showed that this plant develops two types of bisexual flowers. Almost all ovules developed and formed seeds with a completely differentiated embryo both under natural conditions in the Arctic and the Antarctic and in a greenhouse in Olsztyn.

  3. Influence of Environmental Changes on Physiology and Development of Polar Vascular Plants

    NASA Astrophysics Data System (ADS)

    Giełwanowska, Irena; Pastorczyk, Marta; Kellmann-Sopyła, Wioleta

    2011-01-01

    Polar vascular plants native to the Arctic and the Antarctic geobotanical zone have been growing and reproducing effectively under difficult environmental conditions, colonizing frozen ground areas formerly covered by ice. Our macroscopic observations and microscopic studies conducted by means of a light microscope (LM) and transmission electron microscope (TEM) concerning the anatomical and ultrastructural observations of vegetative and generative tissue in Cerastium arcticum, Colobanthus quitensis, Silene involucrata, plants from Caryophyllaceae and Deschampsia antarctica, Poa annua and Poa arctica, from Poaceae family. In the studies, special attention was paid to plants coming from diversity habitats where stress factors operated with clearly different intensity. In all examinations plants, differences in anatomy were considerable. In Deschampsia antarctica the adaxial epidermis of hairgrass leaves from a humid microhabitat, bulliform cells differentiated. Mesophyll was composed of cells of irregular shapes and resembled aerenchyma. The ultrastructural observations of mesophyll in all plants showed tight adherence of chloroplasts, mitochondria and peroxisomes, surface deformations of these organelles and formation of characteristic outgrowths and pocket concavities filled with cytoplasm with vesicles and organelles by chloroplasts. In reproduction biology of examined Caryophyllaceae and Poaceae plants growing in natural conditions, in the Arctic and in the Antarctic, and in a greenhouse in Olsztyn showed that this plant develops two types of bisexual flowers. Almost all ovules developed and formed seeds with a completely differentiated embryo both under natural conditions in the Arctic and the Antarctic and in a greenhouse in Olsztyn.

  4. [Effects of moisture content in organic substrate on the physiological characters, fruit quality and yield of tomato plant].

    PubMed

    Xia, Xiu-Bo; Yu, Xian-Chang; Gao, Jun-Jie

    2007-12-01

    With tomato cultivar Qifen as test crop, this paper studied its growth, physiological characters, fruit yield, fruit quality, and water use efficiency (WUE) under effects of relative moisture content of organic substrate. The results showed that with increasing moisture content in organic substrate, the plant height, stem diameter, node length, leaf area per plant, leaf pigment content, water potential, osmotic potential, root vigor, and fruit yield increased markedly, but fruit quality and WUE decreased significantly. Considering from the aspects of fruit yield, fruit quality and WUE, 80% moisture content of organic substrate could be used as a favorable quantitative index for the water management of tomato cultivation, under which, 26 kg x m(-2) fruit yield could be achieved. If only considering fruit quality, 50% moisture content could be used as the index for water management.

  5. Diverse functional roles of monosaccharide transporters and their homologs in vascular plants: a physiological perspective.

    PubMed

    Slewinski, Thomas L

    2011-07-01

    Vascular plants contain two gene families that encode monosaccharide transporter proteins. The classical monosaccharide transporter(-like) gene superfamily is large and functionally diverse, while the recently identified SWEET transporter family is smaller and, thus far, only found to transport glucose. These transporters play essential roles at many levels, ranging from organelles to the whole plant. Many family members are essential for cellular homeostasis and reproductive success. Although most transporters do not directly participate in long-distance transport, their indirect roles greatly impact carbon allocation and transport flux to the heterotrophic tissues of the plant. Functional characterization of some members from both gene families has revealed their diverse roles in carbohydrate partitioning, phloem function, resource allocation, plant defense, and sugar signaling. This review highlights the broad impacts and implications of monosaccharide transport by describing some of the functional roles of the monosaccharide transporter(-like) superfamily and the SWEET transporter family.

  6. Co-ordination of physiological and morphological responses of stomata to elevated [CO2] in vascular plants.

    PubMed

    Haworth, Matthew; Elliott-Kingston, Caroline; McElwain, Jennifer C

    2013-01-01

    Plant stomata display a wide range of short-term behavioural and long-term morphological responses to atmospheric carbon dioxide concentration ([CO(2)]). The diversity of responses suggests that plants may have different strategies for controlling gas exchange, yet it is not known whether these strategies are co-ordinated in some way. Here, we test the hypothesis that there is co-ordination of physiological (via aperture change) and morphological (via stomatal density change) control of gas exchange by plants. We examined the response of stomatal conductance (G(s)) to instantaneous changes in external [CO(2)] (C(a)) in an evolutionary cross-section of vascular plants grown in atmospheres of elevated [CO(2)] (1,500 ppm) and sub-ambient [O(2)] (13.0 %) compared to control conditions (380 ppm CO(2), 20.9 % O(2)). We found that active control of stomatal aperture to [CO(2)] above current ambient levels was not restricted to angiosperms, occurring in the gymnosperms Lepidozamia peroffskyana and Nageia nagi. The angiosperm species analysed appeared to possess a greater respiratory demand for stomatal movement than gymnosperm species displaying active stomatal control. Those species with little or no control of stomatal aperture (termed passive) to C(a) were more likely to exhibit a reduction in stomatal density than species with active stomatal control when grown in atmospheres of elevated [CO(2)]. The relationship between the degree of stomatal aperture control to C(a) above ambient and the extent of any reduction in stomatal density may suggest the co-ordination of physiological and morphological responses of stomata to [CO(2)] in the optimisation of water use efficiency. This trade-off between stomatal control strategies may have developed due to selective pressures exerted by the costs associated with passive and active stomatal control.

  7. Minor physiological response to elevated CO/sub 2/ by the CAM plant Agave vilmoriniana

    SciTech Connect

    Szarek, S.R.; Holthe, P.A.; Ting, I.P.

    1987-04-01

    One-year-old plants of the CAM leaf succulent Agave vilmoriniana Berger were grown outdoors at Riverside, California. Potted plants were acclimated to CO/sub 2/-enrichment (about 750 microliters per liter) by growth for 2 weeks in an open-top polyethylene chamber. Control plants were grown nearby where the ambient CO/sub 2/ concentration was about 370 microliters per liter. When the plants were well watered, CO/sub 2/-induced differences in stomatal conductances and CO/sub 2/ assimilation rates over the entire 24-hour period were not large. There was a large nocturnal acidification in both CO/sub 2/ treatments and insignificant differences in leaf chlorophyll content. Well watered plants maintained water potentials of -0.3 to -0.4 megapascals. When other plants were allowed to dry to water potentials of -1.2 to -1.7 megapascals, stomatal conductances and CO/sub 2/ uptake rates were reduced in magnitude, with the biggest difference in Phase IV photosynthesis. The minor nocturnal response to CO/sub 2/ by this species is interpreted to indicate saturated, or nearly saturated, phosphoenolpyruvate carboxylase activity at current atmospheric CO/sub 2/ concentrations. CO/sub 2/-enhanced diurnal activity of ribulose bisphosphate carboxylase activity remains a possibility.

  8. Minor Physiological Response to Elevated CO2 by the CAM Plant Agave vilmoriniana1

    PubMed Central

    Szarek, Stan R.; Holthe, Peter A.; Ting, Irwin P.

    1987-01-01

    One-year-old plants of the CAM leaf succulent Agave vilmoriniana Berger were grown outdoors at Riverside, California. Potted plants were acclimated to CO2-enrichment (about 750 microliters per liter) by growth for 2 weeks in an open-top polyethylene chamber. Control plants were grown nearby where the ambient CO2 concentration was about 370 microliters per liter. When the plants were well watered, CO2-induced differences in stomatal conductances and CO2 assimilation rates over the entire 24-hour period were not large. There was a large nocturnal acidification in both CO2 treatments and insignificant differences in leaf chlorophyll content. Well watered plants maintained water potentials of −0.3 to −0.4 megapascals. When other plants were allowed to dry to water potentials of −1.2 to −1.7 megapascals, stomatal conductances and CO2 uptake rates were reduced in magnitude, with the biggest difference in Phase IV photosynthesis. The minor nocturnal response to CO2 by this species is interpreted to indicate saturated, or nearly saturated, phosphoenolpyruvate carboxylase activity at current atmospheric CO2 concentrations. CO2-enhanced diurnal activity of ribulose bisphosphate carboxylase activity remains a possibility. PMID:16665367

  9. A model framework to represent plant-physiology and rhizosphere processes in soil profile simulation models

    NASA Astrophysics Data System (ADS)

    Vanderborght, J.; Javaux, M.; Couvreur, V.; Schröder, N.; Huber, K.; Abesha, B.; Schnepf, A.; Vereecken, H.

    2013-12-01

    Plant roots play a crucial role in several key processes in soils. Besides their impact on biogeochemical cycles and processes, they also have an important influence on physical processes such as water flow and transport of dissolved substances in soils. Interaction between plant roots and soil processes takes place at different scales and ranges from the scale of an individual root and its directly surrounding soil or rhizosphere over the scale of a root system of an individual plant in a soil profile to the scale of vegetation patterns in landscapes. Simulation models that are used to predict water flow and solute transport in soil-plant systems mainly focus on the individual plant root system scale, parameterize single-root scale phenomena, and aggregate the root system scale to the vegetation scale. In this presentation, we will focus on the transition from the single root to the root system scale. Using high resolution non-invasive imaging techniques and methods, gradients in soil properties and states around roots and their difference from the bulk soil properties could be demonstrated. Recent developments in plant sciences provide new insights in the mechanisms that control water fluxes in plants and in the adaptation of root properties or root plasticity to changing soil conditions. However, since currently used approaches to simulate root water uptake neither resolve these small scale processes nor represent processes and controls within the root system, transferring this information to the whole soil-plant system scale is a challenge. Using a simulation model that describes flow and transport processes in the soil, resolves flow and transport towards individual roots, and describes flow and transport within the root system, such a transfer could be achieved. We present a few examples that illustrate: (i) the impact of changed rhizosphere hydraulic properties, (ii) the effect of root hydraulic properties and root system architecture, (iii) the regulation

  10. Physiologically-Mediated Self/Non-Self Root Discrimination in Trifolium repens has Mixed Effects on Plant Performance

    PubMed Central

    de Kroon, Hans; Novoplansky, Ariel

    2006-01-01

    Recent studies suggest that plant roots can avoid competition with other roots of the same plant, but the mechanism behind this behavior is yet largely unclear and their effects on plant performance hardly studied. We grew combinations of two ramets of Trifolium repens in a single pot that were either intact, disconnected for a shorter or longer time, or that belonged to different genotypes. Interconnected ramets developed lower root length and mass than any other combination of ramets, supporting the notion that self/non-self discrimination in T. repens was based entirely on physiological coordination between different roots that develop on the same plant, rather than biochemical allorecognition. These responses were consistent among eight field-collected genotypes, suggesting that self/non-self discrimination is a common feature in wild populations of white clover. There were no significant treatment x genotype interactions suggesting that genetic variation for self/non-self discrimination may be limited. Self-interactions resulted in lower to similar shoot biomass and number of ramets, but higher flowering probabilities, compared to non-self interactions. Thus, our results demonstrated that the performance consequences of self/non-self discrimination may be more complicated than previously thought. PMID:19521491

  11. Research Progress on the use of Plant Allelopathy in Agriculture and the Physiological and Ecological Mechanisms of Allelopathy.

    PubMed

    Cheng, Fang; Cheng, Zhihui

    2015-01-01

    Allelopathy is a common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms. These biochemicals are known as allelochemicals and have beneficial or detrimental effects on target organisms. Plant allelopathy is one of the modes of interaction between receptor and donor plants and may exert either positive effects (e.g., for agricultural management, such as weed control, crop protection, or crop re-establishment) or negative effects (e.g., autotoxicity, soil sickness, or biological invasion). To ensure sustainable agricultural development, it is important to exploit cultivation systems that take advantage of the stimulatory/inhibitory influence of allelopathic plants to regulate plant growth and development and to avoid allelopathic autotoxicity. Allelochemicals can potentially be used as growth regulators, herbicides, insecticides, and antimicrobial crop protection products. Here, we reviewed the plant allelopathy management practices applied in agriculture and the underlying allelopathic mechanisms described in the literature. The major points addressed are as follows: (1) Description of management practices related to allelopathy and allelochemicals in agriculture. (2) Discussion of the progress regarding the mode of action of allelochemicals and the physiological mechanisms of allelopathy, consisting of the influence on cell micro- and ultra-structure, cell division and elongation, membrane permeability, oxidative and antioxidant systems, growth regulation systems, respiration, enzyme synthesis and metabolism, photosynthesis, mineral ion uptake, protein and nucleic acid synthesis. (3) Evaluation of the effect of ecological mechanisms exerted by allelopathy on microorganisms and the ecological environment. (4) Discussion of existing problems and proposal for future research directions in this field to provide a useful reference for future studies on plant

  12. Research Progress on the use of Plant Allelopathy in Agriculture and the Physiological and Ecological Mechanisms of Allelopathy

    PubMed Central

    Cheng, Fang; Cheng, Zhihui

    2015-01-01

    Allelopathy is a common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms. These biochemicals are known as allelochemicals and have beneficial or detrimental effects on target organisms. Plant allelopathy is one of the modes of interaction between receptor and donor plants and may exert either positive effects (e.g., for agricultural management, such as weed control, crop protection, or crop re-establishment) or negative effects (e.g., autotoxicity, soil sickness, or biological invasion). To ensure sustainable agricultural development, it is important to exploit cultivation systems that take advantage of the stimulatory/inhibitory influence of allelopathic plants to regulate plant growth and development and to avoid allelopathic autotoxicity. Allelochemicals can potentially be used as growth regulators, herbicides, insecticides, and antimicrobial crop protection products. Here, we reviewed the plant allelopathy management practices applied in agriculture and the underlying allelopathic mechanisms described in the literature. The major points addressed are as follows: (1) Description of management practices related to allelopathy and allelochemicals in agriculture. (2) Discussion of the progress regarding the mode of action of allelochemicals and the physiological mechanisms of allelopathy, consisting of the influence on cell micro- and ultra-structure, cell division and elongation, membrane permeability, oxidative and antioxidant systems, growth regulation systems, respiration, enzyme synthesis and metabolism, photosynthesis, mineral ion uptake, protein and nucleic acid synthesis. (3) Evaluation of the effect of ecological mechanisms exerted by allelopathy on microorganisms and the ecological environment. (4) Discussion of existing problems and proposal for future research directions in this field to provide a useful reference for future studies on plant

  13. Physiological and biochemical changes in Brassica juncea plants under Cd-induced stress.

    PubMed

    Kapoor, Dhriti; Kaur, Satwinderjeet; Bhardwaj, Renu

    2014-01-01

    Plants of Brassica juncea L. var. RLC-1 were exposed for 30 days to different concentrations (0, 0.2, 0.4, and 0.6 mM) of cadmium (Cd) to analyze the Cd uptake, H2O2 content, hormonal profiling, level of photosynthetic pigments (chlorophyll, carotenoid, and flavonoid), gaseous exchange parameters (photosynthetic rate, vapour pressure deficit, intercellular CO2 concentration, and intrinsic mesophyll rate), antioxidative enzymes (superoxide dismutase, polyphenol oxidase, glutathione-S transferase, and glutathione peroxidase), antioxidant assays (DPPH, ABTS, and total phenolic content), and polyphenols. Results of the present study revealed the increased H2O2 content and Cd uptake with increasing metal doses. UPLC analysis of plants showed the presence of various polyphenols. Gaseous exchange measurements were done by infrared gas analyzer (IRGA), which was negatively affected by metal treatment. In addition, LC/MS study showed the variation in the expression of plant hormones. Level of photosynthetic pigments and activities of antioxidative enzymes were altered significantly in response to metal treatment. In conclusion, the antioxidative defence system of plants got activated due to heavy metal stress, which protects the plants by scavenging free radicals.

  14. Physiological and Biochemical Changes in Brassica juncea Plants under Cd-Induced Stress

    PubMed Central

    Kaur, Satwinderjeet; Bhardwaj, Renu

    2014-01-01

    Plants of Brassica juncea L. var. RLC-1 were exposed for 30 days to different concentrations (0, 0.2, 0.4, and 0.6 mM) of cadmium (Cd) to analyze the Cd uptake, H2O2 content, hormonal profiling, level of photosynthetic pigments (chlorophyll, carotenoid, and flavonoid), gaseous exchange parameters (photosynthetic rate, vapour pressure deficit, intercellular CO2 concentration, and intrinsic mesophyll rate), antioxidative enzymes (superoxide dismutase, polyphenol oxidase, glutathione-S transferase, and glutathione peroxidase), antioxidant assays (DPPH, ABTS, and total phenolic content), and polyphenols. Results of the present study revealed the increased H2O2 content and Cd uptake with increasing metal doses. UPLC analysis of plants showed the presence of various polyphenols. Gaseous exchange measurements were done by infrared gas analyzer (IRGA), which was negatively affected by metal treatment. In addition, LC/MS study showed the variation in the expression of plant hormones. Level of photosynthetic pigments and activities of antioxidative enzymes were altered significantly in response to metal treatment. In conclusion, the antioxidative defence system of plants got activated due to heavy metal stress, which protects the plants by scavenging free radicals. PMID:25133178

  15. Mercury and plants in contaminated soils. 2: Environmental and physiological factors governing mercury flux to the atmosphere

    SciTech Connect

    Leonard, T.L.; Gustin, M.S.; Fernandez, G.C.J.; Taylor, G.E. Jr.

    1998-10-01

    The objective of this study was to evaluate the role of physiological and environmental factors in governing the flux of elemental mercury from plants to the atmosphere. Five species (Lepidium latifolium, Artemisia douglasiana, Caulanthus sp., Fragaria vesca, and Eucalyptus globulus) with different ecological and physiological attributes and growing in soils with high levels of mercury contamination were examined. Studies were conducted in a whole-plant, gas-exchange chamber providing precise control of environmental conditions, and mercury flux was estimated using the mass balance approach. Mercury flux increased linearly as a function of temperature within the range of 20 to 40 C, and the mean temperature coefficient (Q{sub 10}) was 2.04. The temperature dependence of mercury flux was attributed to changes in the contaminant`s vapor pressure in the leaf interior. Mercury flux from foliage increased linearly as a function of irradiance within the range of 500 to 1,500 {micro}mol m/s, and the light enhancement of mercury flux was within a factor of 2.0 to 2.5 for all species. Even though the leaf-to-atmosphere diffusive path for mercury vapor from foliage is similar to that of water vapor, stomatal conductance played a secondary role in governing mercury flux. In a quantitative comparison with other studies in both laboratory and field settings, a strong linear relationship is evident between mercury vapor flux and the natural logarithm of soil mercury concentration, and this relationship may have predictive value in developing regional- and continental-scale mercury budgets. The most critical factors governing mercury flux from plants are mercury concentration in the soil, leaf area index, temperature, and irradiance.

  16. Antecedent plant physiological performance influences the metabolic acceleration of semi-arid soils in response to rainfall

    NASA Astrophysics Data System (ADS)

    Potts, D. L.; Barron-Gafford, G. A.; Jenerette, D.

    2011-12-01

    In semi-arid ecosystems precipitation often arrives as discrete rainfall events. Under these conditions of episodic resource availability, natural selection might favor rapid metabolic responses to the sudden availability of otherwise limiting resources. We introduce and define the term metabolic acceleration (α) as the first derivative of the metabolic rate of a biological system. In other words, α describes the ability of a biological system to up- and down-regulate metabolic rate. Examples include, but are not limited to, the metabolic acceleration of leaf maximum net CO2 assimilation (αAnet), of the CO2 efflux produced by roots and soil microbes (αsoil), and of net ecosystem CO2 exchange (αNEE). To better understand αsoil in relation to seasonal patterns of rainfall and plant physiological performance, we compared three microhabitats (under mesquite, under bunchgrasses, and in intercanopy soils) in a semi-arid shrubland near Tucson, Arizona. Across microhabitats, maximum αsoil varied seasonally such that αsoil was greatest during the warm, wet summer months and lowest during cool winter months. Furthermore, throughout course of the year αsoil beneath mesquites was greater than beneath bunchgrasses or in intercanopy soils. Finally, microhabitat-specific responses of αsoil to the onset of the North American monsoon were consistent with patterns of antecedent plant physiological performance. By quantifying the ability of living systems to respond to episodic resource availability, metabolic acceleration provides a new perspective on the biological significance of antecedent conditions in pulse-driven ecosystems. Finally, that αAnet varies among plant functional types and that αsoil varies among microhabitats suggests the potential for the existence of previously unrecognized life-history trade-offs involving the ability of biological systems to rapidly adjust their metabolic rate in response to episodic resource availability.

  17. Physiological and biochemical response of plants to engineered NMs: Implications on future design.

    PubMed

    de la Rosa, Guadalupe; García-Castañeda, Concepción; Vázquez-Núñez, Edgar; Alonso-Castro, Ángel Josabad; Basurto-Islas, Gustavo; Mendoza, Ángeles; Cruz-Jiménez, Gustavo; Molina, Carlos

    2017-01-01

    Engineered nanomaterials (ENMs) form the basis of a great number of commodities that are used in several areas including energy, coatings, electronics, medicine, chemicals and catalysts, among others. In addition, these materials are being explored for agricultural purposes. For this reason, the amount of ENMs present as nanowaste has significantly increased in the last few years, and it is expected that ENMs levels in the environment will increase even more in the future. Because plants form the basis of the food chain, they may also function as a point-of-entry of ENMs for other living systems. Understanding the interactions of ENMs with the plant system and their role in their potential accumulation in the food chain will provide knowledge that may serve as a decision-making framework for the future design of ENMs. The purpose of this paper was to provide an overview of the current knowledge on the transport and uptake of selected ENMs, including Carbon Based Nanomaterials (CBNMs) in plants, and the implication on plant exposure in terms of the effects at the macro, micro, and molecular level. We also discuss the interaction of ENMs with soil microorganisms. With this information, we suggest some directions on future design and areas where research needs to be strengthened. We also discuss the need for finding models that can predict the behavior of ENMs based on their chemical and thermodynamic nature, in that few efforts have been made within this context.

  18. Final Report: Plant Physiological Aspects of Silicon, July 20, 1994 - July 19, 1998

    SciTech Connect

    Epstein, Emanuel

    2000-01-21

    The object of the research of the project was to demonstrate that Si-replete plants prefer Si-deprived ones that the latter are defined to an extent ''experimental artifacts.'' The research was to ''concentrate on describing mechanical and biochemical features.

  19. Physiological and behavioral responses in Drosophila melanogaster to odorants present at different plant maturation stages.

    PubMed

    Versace, Elisabetta; Eriksson, Anna; Rocchi, Federico; Castellan, Irene; Sgadò, Paola; Haase, Albrecht

    2016-09-01

    The fruit fly Drosophila melanogaster feeds and oviposits on fermented fruit, hence its physiological and behavioral responses are expected to be tuned to odorants abundant during later stages of fruit maturation. We used a population of about two-hundred isogenic lines of D. melanogaster to assay physiological responses (electroantennograms (EAG)) and behavioral correlates (preferences and choice ratio) to odorants found at different stages of fruit maturation. We quantified electrophysiological and behavioral responses of D. melanogaster for the leaf compound β-cyclocitral, as well as responses to odorants mainly associated with later fruit maturation stages. Electrophysiological and behavioral responses were modulated by the odorant dose. For the leaf compound we observed a steep dose-response curve in both EAG and behavioral data and shallower curves for odorants associated with later stages of maturation. Our data show the connection between sensory and behavioral responses and are consistent with the specialization of D. melanogaster on fermented fruit and avoidance of high doses of compounds associated with earlier stages of maturation. Odor preferences were modulated in a non-additive way when flies were presented with two alternative odorants, and combinations of odorants elicited higher responses than single compounds.

  20. Physiological effects of the air pollutant hydrogen fluoride on phloem transport in soybean plants

    SciTech Connect

    Madkour, S.A.A.S.

    1984-01-01

    The effect of continuous exposure to HF at ca. 0, 1, and 5 ugF m/sup -3/ for 8-10 days on the transport and relative distribution of /sup 14/C-labelled photosynthetic assimilates in Hodgson soybean plants at three stages of development (vegetative, flowering and early fruit set, and pod filling) were investigated. Fumigated and non-fumigated plants were supplied with /sup 14/CO/sub 2/ by enclosing the second fully-expanded trifoliolate leaf in a cuvette designed for the purpose. Results from these experiments indicate that transport from the source leaves of /sup 14/C-labelled assimilates to sink tissues was partially inhibited by exposure to both concentrations of HF and at each stage of development. However, the greatest degree of inhibition in the transport occurred in plants that were exposed during the flowering stage. Results indicated that there was a greater retention of sugars and a greater incorporation of the /sup 14/C into non-transport compounds in the source leaves accompanied by a reduced transport to sink tissue as the HF concentration increases. This suggested that F-induced inhibition of phloem loading of sugars. The effect of HF fumigation on phloem loading was investigated by monitoring the uptake of /sup 14/C-sucrose supplied to source leaf discs, collected from fumigated and non-fumigated plants. HF was shown to inhibit the loading of /sup 14/C-sucrose. The effect of F on the activity of plasma membrane ATPase was investigated both in vivo, by isolating plasma membranes from fumigated and non-fumigated plants, and in vitro by exposure of plasma membranes to NaF. F was shown to inhibit ATPase activity both in vivo and in vitro. It is concluded that plasma membrane ATPases is the target site for F inhibition of phloem transport, and that the inhibition occurs through the formation of Mg/sup +2/-fluorophosphate complexes.

  1. Physiological Characterization of a Plant Mitochondrial Calcium Uniporter in Vitro and in Vivo.

    PubMed

    Teardo, Enrico; Carraretto, Luca; Wagner, Stephan; Formentin, Elide; Behera, Smrutisanjita; De Bortoli, Sara; Larosa, Véronique; Fuchs, Philippe; Lo Schiavo, Fiorella; Raffaello, Anna; Rizzuto, Rosario; Costa, Alex; Schwarzländer, Markus; Szabò, Ildiko

    2017-02-01

    Over the recent years, several proteins that make up the mitochondrial calcium uniporter complex (MCUC) mediating Ca(2+)uptake into the mitochondrial matrix have been identified in mammals, including the channel-forming protein MCU. Although six MCU gene homologs are conserved in the model plant Arabidopsis (Arabidopsis thaliana) in which mitochondria can accumulate Ca(2+), a functional characterization of plant MCU homologs has been lacking. Using electrophysiology, we show that one isoform, AtMCU1, gives rise to a Ca(2+)-permeable channel activity that can be observed even in the absence of accessory proteins implicated in the formation of the active mammalian channel. Furthermore, we provide direct evidence that AtMCU1 activity is sensitive to the mitochondrial calcium uniporter inhibitors Ruthenium Red and Gd(3+), as well as to the Arabidopsis protein MICU, a regulatory MCUC component. AtMCU1 is prevalently expressed in roots, localizes to mitochondria, and its absence causes mild changes in Ca(2+) dynamics as assessed by in vivo measurements in Arabidopsis root tips. Plants either lacking or overexpressing AtMCU1 display root mitochondria with altered ultrastructure and show shorter primary roots under restrictive growth conditions. In summary, our work adds evolutionary depth to the investigation of mitochondrial Ca(2+) transport, indicates that AtMCU1, together with MICU as a regulator, represents a functional configuration of the plant mitochondrial Ca(2+) uptake complex with differences to the mammalian MCUC, and identifies a new player of the intracellular Ca(2+) regulation network in plants.

  2. Alkane distribution and carbon isotope composition in fossil leaves: An interpretation of plant physiology in the geologic past

    NASA Astrophysics Data System (ADS)

    Graham, H. V.; Freeman, K. H.

    2014-12-01

    The relative chain-length distribution and carbon-isotope composition of n-alkanes extracted from sedimentary rocks are important geochemical tools for investigating past terrestrial ecosystems. Alkanes preserved in ancient sediments are assumed to be contemporaneous, derived from the same ecosystem, and integrated from the biomass present on the landscape at the time of deposition. Further, there is an underlying assumption that ancient plants exhibited the same metabolic and physiological responses to climate conditions that are observed for modern plants. Interpretations of alkane abundances and isotopic signatures are complicated by the strong influence of phylogenetic affiliation and ecological factors, such as canopy structure. A better understanding of how ecosystem and taxa influence alkane properties, including homologue abundance patterns and leaf-lipid carbon isotope fractionation would help strengthen paleoecological interpretations based on these widely employed plant biomarkers. In this study, we analyze the alkane chain-length distribution and carbon-isotope composition of phytoleim and alkanes (d13Cleaf and d13Clipid) extracted from a selection of Cretaceous and Paleocene fossil leaves from the Guaduas and Cerrejon Formations of Colombia. These data were compared with data for the same families in a modern analogue biome. Photosynthetic and biosynthetic fractionation (∆leaf and elipid) values determined from the fossil material indicate carbon metabolism patterns were similar to modern plants. Fossil data were incorporated in a biomass-weighted mixing model to represent the expected lipid complement of sediment arising from this ecosystem and compared with alkane measurements from the rock matrix. Modeled and observed isotopic and abundance patterns match well for alkane homologs most abundant in plants (i.e., n-C27 to n-C33). The model illustrates the importance of understanding biases in litter flux and taphonomic pressures inherent in the

  3. Effect of Seed Position on Parental Plant on Proportion of Seeds Produced with Nondeep and Intermediate Physiological Dormancy

    PubMed Central

    Lu, Juan J.; Tan, Dun Y.; Baskin, Carol C.; Baskin, Jerry M.

    2017-01-01

    The position in which seeds develop on the parental plant can have an effect on dormancy-break and germination. We tested the hypothesis that the proportion of seeds with intermediate physiological dormancy (PD) produced in the proximal position on a raceme of Isatis violascens plants is higher than that produced in the distal position, and further that this difference is related to temperature during seed development. Plants were watered at 3-day intervals, and silicles and seeds from the proximal (early) and distal (late) positions of racemes on the same plants were collected separately and tested for germination. After 0 and 6 months dry storage at room temperature (afterripening), silicles and seeds were cold stratified for 0–16 weeks and tested for germination. Mean daily maximum and minimum temperatures during development/maturation of the two groups of seeds did not differ. A higher proportion of seeds with the intermediate level than with the nondeep level of PD was produced by silicles in the proximal position than by those in the distal position, while the proportion of seeds with nondeep PD was higher in the distal than in the proximal position of the raceme. The differences were not due only to seed mass. Since temperature and soil moisture conditions were the same during development of the seeds in the raceme, differences in proportion of seeds with intermediate and nondeep PD are attributed to position on parental plant. The ecological consequence of this phenomenon is that it ensures diversity in dormancy-breaking and germination characteristics within a seed cohort, a probable bet-hedging strategy. This is the first demonstration of position effects on level of PD in the offspring. PMID:28232842

  4. Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient1[OPEN

    PubMed Central

    Mullinix, George W.R.; Ward, Joy K.

    2016-01-01

    Rising atmospheric carbon dioxide concentration ([CO2]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO2] gradient (180–1,000 µL L−1). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO2] and arbuscular mycorrhizal fungi. To evaluate [CO2] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (MBio) and nonmycorrhizal (NMBio) plants (RBio = [MBio − NMBio]/NMBio). We then assessed linkages between RBio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, RBio increased with rising [CO2], shifting from negative to positive values at 700 µL L−1. [CO2] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in RBio in this species. For T. ceratophorum, RBio increased from 180 to 390 µL L−1 and further increases in [CO2] caused RBio to shift from positive to negative values. [CO2] and fungal effects on plant growth and carbon sink strength were correlated with shifts in RBio in this species. Overall, we show that rising [CO2] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO2], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO2]. The magnitude and mechanisms driving mycorrhizal-CO2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. PMID:27573369

  5. Effect of Seed Position on Parental Plant on Proportion of Seeds Produced with Nondeep and Intermediate Physiological Dormancy.

    PubMed

    Lu, Juan J; Tan, Dun Y; Baskin, Carol C; Baskin, Jerry M

    2017-01-01

    The position in which seeds develop on the parental plant can have an effect on dormancy-break and germination. We tested the hypothesis that the proportion of seeds with intermediate physiological dormancy (PD) produced in the proximal position on a raceme of Isatis violascens plants is higher than that produced in the distal position, and further that this difference is related to temperature during seed development. Plants were watered at 3-day intervals, and silicles and seeds from the proximal (early) and distal (late) positions of racemes on the same plants were collected separately and tested for germination. After 0 and 6 months dry storage at room temperature (afterripening), silicles and seeds were cold stratified for 0-16 weeks and tested for germination. Mean daily maximum and minimum temperatures during development/maturation of the two groups of seeds did not differ. A higher proportion of seeds with the intermediate level than with the nondeep level of PD was produced by silicles in the proximal position than by those in the distal position, while the proportion of seeds with nondeep PD was higher in the distal than in the proximal position of the raceme. The differences were not due only to seed mass. Since temperature and soil moisture conditions were the same during development of the seeds in the raceme, differences in proportion of seeds with intermediate and nondeep PD are attributed to position on parental plant. The ecological consequence of this phenomenon is that it ensures diversity in dormancy-breaking and germination characteristics within a seed cohort, a probable bet-hedging strategy. This is the first demonstration of position effects on level of PD in the offspring.

  6. Effects of Riyadh cement industry pollutions on some physiological and morphological factors of Datura innoxia Mill. plant

    PubMed Central

    Salama, Hediat M.H.; Al-Rumaih, M.M.; Al-Dosary, M.A.

    2011-01-01

    Cement factory emissions into air cause serious air pollution and affect the plant and animal life in the environment. Herein, we report the effects of cement industry emissions (O3, SO2 and NO2) in air, as pollutants, at Riyadh City on Datura innoxia Mill. plant. Morphological characters including plant height, leaves area and number, fresh and dry weight of shoot and root systems of D. innoxia showed a significant reduction from their normal control plants as a response to exposure to pollutant emissions. Chlorophyll and carotenoid contents recorded reductions in values compared to control plant, and the lowest values of chlorophyll A, B, total chlorophyll, carotenoids and total pigments were 0.431, 0.169, 0.60, 0.343 and 0.943 mg/g respectively at a distance of 1–5 m from the cement factory in fruiting stage. These changes in values may be attributed to a probable deceleration of the biosynthetic process rather than degradation of pigments. Further D. innoxia showed a significant (P < 0.01) reduction in non-reducing and total sugars, protein and total lipid contents compared with the control plant. The root system recorded the lowest values of reducing sugars (0.350 mg/g f. wt.), non-reducing sugars (0.116 mg/g f. wt.), total sugars (0.466 mg/g f. wt.), protein content (0.931 mg/g f. wt.) and total lipids content (0.669 mg/g f. wt.) in fruiting stage at a distance of 1–5 m from the cement factory. The peroxidase activity of shoot and root systems of the studied plant was also significantly higher than those of control plant. Thus a highest value of (29.616 units/g f. wt.) peroxidase activity was recorded in vegetative stage of shoot system at a distance 1–5 m from the cement factory. Results of the study indicated that cement industry emission strongly influence the physiology and morphology of date palm D. innoxia which contribute date fruits, a staple food in the Arab world. PMID:23961129

  7. Physiological and genetic characterization of plant growth and gravitropism in LED light sources

    NASA Technical Reports Server (NTRS)

    Deitzer, Gerald F.

    1994-01-01

    Among the many problems of growing plants in completely controlled environments, such as those anticipated for the space station and the CELSS program, is the need to provide light that is both adequate for photosynthesis and of proper quality for normal growth and development. NASA scientists and engineers have recently become interested in the possibility of utilizing densely packed, solid state, light emitting diodes (LED's) as a source for this light. Unlike more conventional incandescent or electrical discharge lamps, these sources are highly monochromatic and lack energy in spectral regions thought to be important for normal plant development. In addition, a recent observation by NASA scientist has suggested that infra-red LED's, that are routinely used as photographic safelights for plants grown in darkness, may interact with the ability of plants to detect gravity. In order to establish how plants respond to light from these LED light sources we carried out a series of experiments with known pigment mutants of the model mustard plant, Arabidopsis thaliana, growing in either a gravity field or on a clinostat to simulate a micro-gravity environment. Results indicate that only red light from the 665 nm LED's disrupts the ability of normal wildtype seedlings to detect a gravity stimulus. There was no consistent effect found for the far-red (735 nm) LED's or either of the infrared (880 nm or 935 nm) LED sources but both showed some effect in one or more of the genotypes tested. Of these five members of the phytochrome multigene family in Arabidopsis, only the phytochrome B pigment mutant (hy3) lacked the ability to detect gravity under all conditions. There was no effect of either micro-gravity (clinostat) or the infra-red LED's on the light induced inhibition of hypocotyl elongation. Measurements of the pigment phytochrome in oats also showed no photoconversion by 15 min irradiations with the infra-red LED's. We conclude that phytochrome B is required for the

  8. Landscape and plant physiological controls on water dynamics and forest productivity within a watershed

    NASA Astrophysics Data System (ADS)

    Hu, Jia; Jencso, Kelsey; Looker, Nathaniel; Martin, Justin; Hoylman, Zachary

    2015-04-01

    Across the Western U.S., declining snowpacks have resulted in increased water limitation, leading to reduced productivity in high elevation forests. While our current understanding of how forests respond to climate change is typically focused on measuring/modeling the physiological responses and climate feedbacks, our study aims to combine physiology with hydrology to examine how landscape topography modulates the sensitivity of forests to climate. In a forested watershed in Western Montana, we linked climate variability to the physical watershed characteristics and the physiological response of vegetation to examine forest transpiration and productivity rates. Across the entire watershed, we found a strong relationship between productivity and the topographic wetness index, a proxy for soil moisture storage. However, this relationship was highly dependent on the intensity of solar radiation, suggesting that at high elevations productivity was limited by temperature, while at low elevations productivity was limited by moisture. In order to identify the mechanisms responsible for this relationship, we then examined how different coniferous species respond to changing environmental and hydrologic regimes. We first examined transpiration and productivity rates at the hillslope scale at four plots, ranging in elevation and aspect across the watershed. We found trees growing in the hollows had higher transpiration and productivity rates than trees growing in the side slope, but that these differences were more pronounced at lower elevations. We then used oxygen isotope to examine water source use by different species across the watershed. We found that trees growing in the hollows used snowmelt for a longer period. This was most likely due to upslope subsidies of snowmelt water to the hollow areas. However, we found that trees growing at lower elevations used proportionally more snowmelt than trees at the higher elevations. This was most likely due to the trees at lower

  9. Evolution and challenges of dynamic global vegetation models for some aspects of plant physiology and elevated atmospheric CO2.

    PubMed

    Rezende, L F C; Arenque, B C; Aidar, S T; Moura, M S B; Von Randow, C; Tourigny, E; Menezes, R S C; Ometto, J P H B

    2016-07-01

    Dynamic global vegetation models (DGVMs) simulate surface processes such as the transfer of energy, water, CO2, and momentum between the terrestrial surface and the atmosphere, biogeochemical cycles, carbon assimilation by vegetation, phenology, and land use change in scenarios of varying atmospheric CO2 concentrations. DGVMs increase the complexity and the Earth system representation when they are coupled with atmospheric global circulation models (AGCMs) or climate models. However, plant physiological processes are still a major source of uncertainty in DGVMs. The maximum velocity of carboxylation (Vcmax), for example, has a direct impact over productivity in the models. This parameter is often underestimated or imprecisely defined for the various plant functional types (PFTs) and ecosystems. Vcmax is directly related to photosynthesis acclimation (loss of response to elevated CO2), a widely known phenomenon that usually occurs when plants are subjected to elevated atmospheric CO2 and might affect productivity estimation in DGVMs. Despite this, current models have improved substantially, compared to earlier models which had a rudimentary and very simple representation of vegetation-atmosphere interactions. In this paper, we describe this evolution through generations of models and the main events that contributed to their improvements until the current state-of-the-art class of models. Also, we describe some main challenges for further improvements to DGVMs.

  10. Evolution and challenges of dynamic global vegetation models for some aspects of plant physiology and elevated atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Rezende, L. F. C.; Arenque, B. C.; Aidar, S. T.; Moura, M. S. B.; Von Randow, C.; Tourigny, E.; Menezes, R. S. C.; Ometto, J. P. H. B.

    2016-07-01

    Dynamic global vegetation models (DGVMs) simulate surface processes such as the transfer of energy, water, CO2, and momentum between the terrestrial surface and the atmosphere, biogeochemical cycles, carbon assimilation by vegetation, phenology, and land use change in scenarios of varying atmospheric CO2 concentrations. DGVMs increase the complexity and the Earth system representation when they are coupled with atmospheric global circulation models (AGCMs) or climate models. However, plant physiological processes are still a major source of uncertainty in DGVMs. The maximum velocity of carboxylation (Vcmax), for example, has a direct impact over productivity in the models. This parameter is often underestimated or imprecisely defined for the various plant functional types (PFTs) and ecosystems. Vcmax is directly related to photosynthesis acclimation (loss of response to elevated CO2), a widely known phenomenon that usually occurs when plants are subjected to elevated atmospheric CO2 and might affect productivity estimation in DGVMs. Despite this, current models have improved substantially, compared to earlier models which had a rudimentary and very simple representation of vegetation-atmosphere interactions. In this paper, we describe this evolution through generations of models and the main events that contributed to their improvements until the current state-of-the-art class of models. Also, we describe some main challenges for further improvements to DGVMs.

  11. A worldwide analysis of within-canopy variations in leaf structural, chemical and physiological traits across plant functional types.

    PubMed

    Niinemets, Ülo; Keenan, Trevor F; Hallik, Lea

    2015-02-01

    Extensive within-canopy light gradients importantly affect the photosynthetic productivity of leaves in different canopy positions and lead to light-dependent increases in foliage photosynthetic capacity per area (AA). However, the controls on AA variations by changes in underlying traits are poorly known. We constructed an unprecedented worldwide database including 831 within-canopy gradients with standardized light estimates for 304 species belonging to major vascular plant functional types, and analyzed within-canopy variations in 12 key foliage structural, chemical and physiological traits by quantitative separation of the contributions of different traits to photosynthetic acclimation. Although the light-dependent increase in AA is surprisingly similar in different plant functional types, they differ fundamentally in the share of the controls on AA by constituent traits. Species with high rates of canopy development and leaf turnover, exhibiting highly dynamic light environments, actively change AA by nitrogen reallocation among and partitioning within leaves. By contrast, species with slow leaf turnover exhibit a passive AA acclimation response, primarily determined by the acclimation of leaf structure to growth light. This review emphasizes that different combinations of traits are responsible for within-canopy photosynthetic acclimation in different plant functional types, and solves an old enigma of the role of mass- vs area-based traits in vegetation acclimation.

  12. Chloroplast Iron Transport Proteins – Function and Impact on Plant Physiology

    PubMed Central

    López-Millán, Ana F.; Duy, Daniela; Philippar, Katrin

    2016-01-01

    Chloroplasts originated about three billion years ago by endosymbiosis of an ancestor of today’s cyanobacteria with a mitochondria-containing host cell. During evolution chloroplasts of higher plants established as the site for photosynthesis and thus became the basis for all life dependent on oxygen and carbohydrate supply. To fulfill this task, plastid organelles are loaded with the transition metals iron, copper, and manganese, which due to their redox properties are essential for photosynthetic electron transport. In consequence, chloroplasts for example represent the iron-richest system in plant cells. However, improvement of oxygenic photosynthesis in turn required adaptation of metal transport and homeostasis since metal-catalyzed generation of reactive oxygen species (ROS) causes oxidative damage. This is most acute in chloroplasts, where radicals and transition metals are side by side and ROS-production is a usual feature of photosynthetic electron transport. Thus, on the one hand when bound by proteins, chloroplast-intrinsic metals are a prerequisite for photoautotrophic life, but on the other hand become toxic when present in their highly reactive, radical generating, free ionic forms. In consequence, transport, storage and cofactor-assembly of metal ions in plastids have to be tightly controlled and are crucial throughout plant growth and development. In the recent years, proteins for iron transport have been isolated from chloroplast envelope membranes. Here, we discuss their putative functions and impact on cellular metal homeostasis as well as photosynthetic performance and plant metabolism. We further consider the potential of proteomic analyses to identify new players in the field. PMID:27014281

  13. Brackish Eutrophic Water Treatment by Iris pseudacorus L.-Planted Microcosms: Physiological Responses of Iris pseudacorus L. to Salinity.

    PubMed

    Zhao, Huilin; Wang, Fen; Ji, Min

    2015-01-01

    Iris pseudacorus L. has been widely used in aquatic ecosystem to remove nutrient and has achieved positive effects. However, little is known regarding the nutrient-removal performance and physiological responses of I. pseudacorus for brackish eutrophic water treatment due to high nutrients combined with certain salinity levels. In this study, I. pseudacorus-planted microcosms were established to evaluate the capacity of I. pseudacorus to remove excessive nutrients from fresh (salinity 0.05%) and brackish (salinity 0.5%) eutrophic waters. The degradation of total nitrogen and ammonia nitrogen were not affected by 0.5% salinity; 0.5% salinity promoted the degradation of nitrate nitrogen while severely inhibited the degradation of total phosphorus. Additionally, 0.5% salinity was found to induce stress responses quantified by measuring six physiological indexes. Compared to 0.05% salinity, 0.5% salinity resulted in significant decreases in the chlorophyll a, b and total chlorophyll contents of I. pseudacorus which closely related to photosynthesis (p < 0.05). Furthermore, the higher proline, malondialdehyde contents and antioxidant enzyme activities were detected in I. pseudacorus exposed to 0.5% salinity, which provided protection against reactive oxygen species. The results highlight that the cellular stress assays are efficient for monitoring the health of I. pseudacorus in salinity shock-associated constructed wetlands.

  14. A LOV protein modulates the physiological attributes of Xanthomonas axonopodis pv. citri relevant for host plant colonization.

    PubMed

    Kraiselburd, Ivana; Alet, Analía I; Tondo, María Laura; Petrocelli, Silvana; Daurelio, Lucas D; Monzón, Jesica; Ruiz, Oscar A; Losi, Aba; Orellano, Elena G

    2012-01-01

    Recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. The photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. Data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the BLUF (Blue Light sensing Using FAD), LOV (Light, Oxygen, Voltage) and phytochrome families with no known functions. Xanthomonas axonopodis pv. citri is a Gram-negative bacterium responsible for citrus canker. The in silico analysis of the X. axonopodis pv. citri genome sequence revealed the presence of a gene encoding a putative LOV photoreceptor, in addition to two genes encoding BLUF proteins. This suggests that blue light sensing could play a role in X. axonopodis pv. citri physiology. We obtained the recombinant Xac-LOV protein by expression in Escherichia coli and performed a spectroscopic analysis of the purified protein, which demonstrated that it has a canonical LOV photochemistry. We also constructed a mutant strain of X. axonopodis pv. citri lacking the LOV protein and found that the loss of this protein altered bacterial motility, exopolysaccharide production and biofilm formation. Moreover, we observed that the adhesion of the mutant strain to abiotic and biotic surfaces was significantly diminished compared to the wild-type. Finally, inoculation of orange (Citrus sinensis) leaves with the mutant strain of X. axonopodis pv. citri resulted in marked differences in the development of symptoms in plant tissues relative to the wild-type, suggesting a role for the Xac-LOV protein in the pathogenic process. Altogether, these results suggest the novel involvement of a photosensory system in the regulation of physiological attributes of a phytopathogenic bacterium. A functional blue light receptor in Xanthomonas spp. has been described for the first time, showing an important

  15. Flooding effects on plant physiology and VOC emissions from Amazonian tree species from two different flooding environments: Varzea and Igapo

    NASA Astrophysics Data System (ADS)

    Bracho Nunez, A.; Knothe, N.; Liberato, M. A. R.; Schebeske, G.; Ciccioli, P.; Piedade, M. T. F.; Kesselmeier, J.

    2009-04-01

    A land area of 300.000 km² in the Amazon basin is subjected to a continuous flooding pulse, being flooded for 210 days a-1 on an average (Junk et al. 1993). To survive the flooding period vegetation has developed several morphological, anatomical and physiological strategies to mitigate the produced stress due to root anoxia. One of the strategies is fermentation of sucrose in the roots to comply with the energy demand under anoxia. The resulting toxic metabolite ethanol is transported through the transpiration stream to the leaves and can be directly emitted into the atmosphere or converted to acetaldehyde and/or acetate, still volatile enough to be partly released. We investigated short-term and long-term flooding effects on physiology and VOC emission by plant species from várzea and igapó and observed ethanol and acetaldehyde emissions from the várzea species Vatairea guianensis after one day of flooding, which decreased considerably within the next three days. The same species from igapó showed no acetaldehyde emission and much lower emission rates of ethanol, than the várzea species. In contrast Hevea spruceana from both várzea and igapó showed no ethanol or acetaldehyde emissions. After long term flooding (2 months) we did not find any emissions of acetaldehyde or ethanol from all plant species investigated. However, isoprene and monoterpene emissions were clearly affected, showing a significant decrease. Carbon dioxide assimilation was not affected by short term flooding, but declined after two months root anoxia in the case of Hevea spruceana.

  16. Physiological and genetic control mechanisms for plant adaptation to high temperature and elevated CO2

    SciTech Connect

    Zeiger, Eduardo

    2001-02-01

    Acclimations of the stomatal response to CO2 were characterized. Stomata from the model plant used, Vicia faba, are very sensitive to ambient CO2 when grown in growth chambers as compared to stomata from green house grown leaves. The different CO2 sensitivities of growth chamber and green house grown guard cells was confirmed by reciprocal transfer experiments. Stomata acclimated to their new environment and acquired the CO2 sensitivity typical of that environment. A mechanism for CO2 sensing was also characterized. Results show that CO2 concentration alters the concentration of zeaxanthin in the guard cell chloroplast, thus modifying the light response of the guard cells. This mechanism accounts for the well characterized interactions of light and CO2 in the stomatal responses. The xanthophyll cycle in the stomata of the facultative CAM plant, Mesembryanthemum crystallinum, was characterized. In the C3 mode, zeaxanthin is formed in the light and stomata open. Upon induction of the CAM mode, zeaxanthin synthesis is blocked and stomata no longer respond to light. These results implicate the regulation of the xanthophyll cycle of guard cells in the CAM adaptation.

  17. Physiological and morphological changes in Salix viminalis L. as a result of plant exposure to copper.

    PubMed

    Gąsecka, Monika; Mleczek, Mirosław; Drzewiceka, Kinga; Magdziak, Zuzanna; Rissmann, Iwona; Chadzinikolau, Tamara; Golinski, Piotr

    2012-01-01

    The aim of this study was to assess the response of Salix viminalis L. under model conditions to different copper concentrations and, as a consequence, potential application of the experimental results in decontamination of water with heavy metal ions (phytoaccumlation). The 14-day experiment was conducted on one-year-old cuttings of Salix viminalis L. 'Cannabina' exposed, in a phytotron, to six different copper levels in hydroponic pots. The results showed that the capacity to accumulate heavy metals was of the following order: roots > rods > shoots > leaves. The linear relationships between the accumulation efficiency of particular Salix parts were confirmed. Together with an increase in copper sorption in above-ground organs, a decrease was observed in root biomass and the length of roots, shoots and leaves. The release of low molecular weight organic acids into solution was different under various Cu levels. Glucose, fructose and sucrose contents in leaves of Salix in all treatments were higher than in control plants. Higher concentration of sugars (4 times higher compared to the control) was detected for fructose in a 2 mM Cu treatment. The total phenolics content rapidly increased only at 3 mM Cu level. Free and total salicylic acid and the glutathione contents in plants treated with copper in relation to the control were always higher and changed with increasing concentration of copper ions in the medium.

  18. Effect of aluminium uptake on physiology, phenols and amino acids in Matricaria chamomilla plants.

    PubMed

    Kovácik, Jozef; Klejdus, Borivoj; Hedbavny, Josef

    2010-06-15

    Chamomile is a widely used medicinal plant and, as observed in our previous studies, also accumulates some metals in its above-ground biomass. We therefore tested selected metabolic responses after treatments with 60 and 120 microM Al for 7 days. Shoot Al content was not elevated in comparison with control (12.3-14.1 microg g(-1) DW) while total root Al increased strongly, reaching 2680 and 4400 microg g(-1) DW in 60 and 120 microM treatments, respectively. "Intra-root" Al represented 83.6 (60 microM treatment) and 75.8% (120 microM treatment) of total root Al. Soluble proteins were not significantly affected. Free amino acids were almost unaffected in shoots while in roots the highest content was found in 60 microM Al. Ascorbate- and guaiacol-peroxidase activities were the highest in 60 microM Al-exposed roots. On the other hand, phenylalanine ammonia-lyase activity, total soluble phenols, flavonoids, a sum of 13 phenolic acids and partially two flavonols (quercetin and kaempferol) increased in the shoots. Present study has shown lower Al toxicity and unaltered shoot Al content seems to be the most positive outcome in comparison with previously tested metals (Cd, Ni and Cu). Our results indicate that phenols in shoots and free amino acids in roots are influenced by Al excess in chamomile plants. Possible mechanisms in the context of available literature are suggested and discussed.

  19. Physiological responses of root-less epiphytic plants to acid rain.

    PubMed

    Kováčik, Jozef; Klejdus, Bořivoj; Bačkor, Martin; Stork, František; Hedbavny, Josef

    2011-03-01

    Selected physiological responses of Tillandsia albida (Bromeliaceae) and two lichens (Hypogymnia physodes and Xanthoria parietina) exposed to simulated acid rain (AR) over 3 months were studied. Pigments were depressed in all species being affected the most in Tillandsia. Amounts of hydrogen peroxide and superoxide were elevated and soluble proteins decreased only in AR-exposed Hypogymnia. Free amino acids were slightly affected among species and only glutamate sharply decreased in AR-exposed Xanthoria. Slight increase in soluble phenols but decrease in flavonoids in almost all species suggests that the latter are not essential for tolerance to AR. Almost all phenolic acids in Tillandsia leaves decreased in response to AR and activities of selected enzymes (phenylalanine ammonia-lyase, polyphenol oxidase, ascorbate- and guaiacol-peroxidase) were enhanced by AR. In lichens, considerable increase in metabolites (physodalic acid, atranorin and parietin) in response to AR was found but amount of ergosterol was unchanged. Macronutrients (K, Ca, Mg) decreased more pronouncedly in comparison with micronutrients in all species. Xanthoria showed higher tolerance in comparison with Hypogymnia, suggesting that could be useful for long-term biomonitoring.

  20. Effects of salinity on anatomical features and physiology of a semi-mangrove plant Myoporum bontioides.

    PubMed

    Xu, H M; Tam, N F Y; Zan, Q J; Bai, M; Shin, P K S; Vrijmoed, L L P; Cheung, S G; Liao, W B

    2014-08-30

    The effect of different concentrations of NaCl, 0, 100, 200, 300 and 400 mM, on the anatomical features and physiology of Myoporum bontioides was investigated. The photosynthetic rates (Pn) were significantly reduced by salt stress, with the lowest values at 400 mM NaCl. The content of malondialdehyde (MDA), proline and soluble sugar, as well as the activities of peroxidase (POD) and catalase (CAT) increased at the beginning, but became similar to the control as the experiment proceeded. The NaCl effect on superoxide dismutase (SOD) was different from the other parameters, with a significant reduction at 400 mM NaCl at Day 7. Salt glands were found in both upper and lower epidermis, and the ratios of the thickness of palisade to spongy mesophyll tissues increased with NaCl concentrations. The medullary ray was clearly damaged by NaCl at levels of 200 and 300 mM. These results demonstrated that M. bontioides could adapt to a relatively low salinity, and was not a halophilous species.

  1. Protection of palak (Beta vulgaris L. var Allgreen) plants from ozone injury by ethylenediurea (EDU): roles of biochemical and physiological variations in alleviating the adverse impacts.

    PubMed

    Tiwari, Supriya; Agrawal, Madhoolika

    2009-06-01

    Ameliorative effects of ethylenediurea (N-[2-(2-oxo-1-imidazolinidyl) ethyl]-N' phenylurea, abbreviated as EDU) against ozone stress were studied on selected growth, biochemical, physiological and yield characteristics of palak (Beta vulgaris L. var Allgreen) plants grown in field at a suburban site of Varanasi, India. Mean eight hourly ozone concentration varied from 52 to 73 ppb which was found to produce adverse impacts on plant functioning and growth characteristics. The palak plants were treated with 300 ppm EDU at 10 days after germination at 10 days interval up to the plant maturity. Lipid peroxidation in EDU treated plants declined significantly as compared to non-EDU treated ones. Significant increment in F(v)/F(m) ratio in EDU treated plants as compared to non-EDU treated ones was recorded. EDU treated plants showed significant increment in ascorbic acid contents and reduction in peroxidase activity as compared to non-EDU treated ones. As a result of the protection provided by EDU against ozone induced stress on biochemical and physiological characteristics of palak, the morphological parameters also responded positively. Significant increments were recorded in shoot length, number of leaves plant(-1), leaf area and root and shoot biomass of EDU treated plants as compared to non-EDU treated ones. Contents of Na, K, Ca, Mg and Fe were higher in EDU treated plants as compared to non-EDU treated ones. The present investigation proves the usefulness of EDU in partially ameliorating ozone injury in ambient conditions.

  2. Workshop on seedling physiology and growth problems in oak plantings (5th) (abstracts). Held in Ames, Iowa on March 4-5, 1992. Forest Service general technical report

    SciTech Connect

    Thompson, J.R.; Schultz, R.C.; Van Sambeek, J.W.

    1993-01-01

    The fifth workshop on seedling physiology and growth problems in oak plantings was held at the Holiday Inn Gateway Center in Ames, Iowa on March 4 and 5, 1992 with more than 45 participants. The workshop continues to serve as an informal forum for researchers to exchange ideas and research results. Papers were divided into four general subject areas: (1) field performance of planted oaks, (2) seedling propagation and production, (3) oak physiology and genetics, and (4) natural and acorn germination regeneration. All abstracts prepared for the workshop are included in the technical report.

  3. Plant physiological and soil characteristics associated with methane and nitrous oxide emission from rice paddy.

    PubMed

    Baruah, K K; Gogoi, Boby; Gogoi, P

    2010-01-01

    Methane (CH4) and nitrous oxide (N2O) are important greenhouse gases causing global warming and climate change. Efforts were made to analyze the CH4 and N2O flux in relation to plant and soil factors from rice (Oryza sativa L.) paddy. Ten popularly grown rice varieties namely Rashmisali, Bogajoha, Basmuthi, Lalkalamdani, Choimora (traditional varieties); Mahsuri, Moniram, Kushal, Gitesh and Profulla (high yielding varieties = HYV) were grown during monsoon season of July 2006. The CH4 and N2O emissions were measured the date of transplanting onwards at weekly interval along with soil and plant parameters. The seasonal integrated CH4 and N2O emission (Esif) from rice ranged from 8.13 g m(-2) to 13.00 g m(-2) and 121.63 mg N2O-N m(-2) to 189.46 mg N2O-N m(-2), respectively. Variety Gitesh emitted less N2O and CH4 amongst all the rice varieties. Both CH4 and N2O emission exhibited a significant positive correlation with leaf area, leaf number, tiller number and root dry weight. Soil organic carbon of the experimental field was associated with both CH4 and N2O emission whereas nitrate-N content of soil was associated with N2O emission. Methane emission showed significant positive correlations with soil temperature and crop photosynthetic rate. Traditional rice varieties with profuse vegetative growth recorded higher CH4 and N2O fluxes compared to HYVs. Gitesh and Kushal having low seasonal CH4 and N2O emission with higher yield potential can be recommended as low greenhouse gas emitting rice varieties.

  4. Physiological changes in barley plants under combined toxicity of aluminum, copper and cadmium.

    PubMed

    Guo, Tian Rong; Zhang, Guo Ping; Zhang, Yan Hua

    2007-06-15

    Crop production on acid soil is markedly reduced, further, a multiple heavy metal pollution except Al on acid soil is detected in many areas. The present study was undertaken to assess the toxicities of Al, Cd, and Cu separately and in combinations, three heavy metals very often coexisting on acid soil, and to identify their interactions in two kinds of barley seedlings differing in Al tolerance. The plant growth, metals accumulations, total soluble protein and sugar contents, MDA contents and the activities of SOD and POD were estimated in roots and leaves after 5-week supply of the heavy metals excess in the nutrient solution. The results indicated that the stress treatments including low pH (pH 4.5) alone all adversely affected plant growth and disturbed the cell metabolism seriously. The development of toxic symptoms corresponded to a high accumulation of Al, Cd, Cu and to a poor increase in soluble sugar contents but to a high increase in MDA contents, to the decrease in soluble protein contents and to the much elevated SOD and POD activities in both roots and leaves. In addition, binary metal combinations of Al+Cd and Al+Cu both produced the synergistic response for the growth of barley seedlings, in particular for Shang 70-119, while, ternary metal combination of Al+Cu+Cd produced different interactions in two kinds of genotypes, thus, the significant synergistic response was seen in Shang 70-119, but the antagonistic response was detected in Gebeina. The different responses to ternary metal combination of two genotypes may result from the different metal bioaccumulation patterns, hence, the existence of Cd and Cu promoted Al accumulation in Shang 70-119 but inhibited Al accumulation in Gebeina.

  5. Plant physiological and environmental controls over the exchange of acetaldehyde between forest canopies and the atmosphere

    NASA Astrophysics Data System (ADS)

    Jardine, K.; Harley, P.; Karl, T.; Guenther, A.; Lerdau, M.; Mak, J. E.

    2008-11-01

    We quantified fine scale sources and sinks of gas phase acetaldehyde in two forested ecosystems in the US. During the daytime, the upper canopy behaved as a net source while at lower heights, reduced emission rates or net uptake were observed. At night, uptake generally predominated throughout the canopies. Net ecosystem emission rates were inversely related to foliar density due to the extinction of light in the canopy and a respective decrease of the acetaldehyde compensation point. This is supported by branch level studies revealing much higher compensation points in the light than in the dark for poplar (Populus deltoides) and holly oak (Quercus ilex) implying a higher light/temperature sensitivity for acetaldehyde production relative to consumption. The view of stomata as the major pathway for acetaldehyde exchange is supported by strong linear correlations between branch transpiration rates and acetaldehyde exchange velocities for both species. In addition, natural abundance carbon isotope analysis of gas-phase acetaldehyde during poplar branch fumigation experiments revealed a significant kinetic isotope effect of 5.1±0.3‰ associated with the uptake of acetaldehyde. Similar experiments with dry dead poplar leaves showed no fractionation or uptake of acetaldehyde, confirming that this is only a property of living leaves. We suggest that acetaldehyde belongs to a potentially large list of plant metabolites where stomatal resistance can exert long term control over both emission and uptake rates due to the presence of both source(s) and sink(s) within the leaf which strongly buffer large changes in concentrations in the substomatal airspace due to changes in stomatal resistance. We conclude that the exchange of acetaldehyde between plant canopies and the atmosphere is fundamentally controlled by ambient acetaldehyde concentrations, stomatal resistance, and the compensation point which is a function of light/temperature.

  6. Plant physiological and environmental controls over the exchange of acetaldehyde between forest canopies and the atmosphere

    NASA Astrophysics Data System (ADS)

    Jardine, K.; Harley, P.; Karl, T.; Guenther, A.; Lerdau, M.; Mak, J. E.

    2008-06-01

    We quantified fine scale sources and sinks of gas phase acetaldehyde in two forested ecosystems in the US. During the daytime, the upper canopy behaved as a net source while at lower heights, reduced emission rates or net uptake were observed. At night, uptake generally predominated thoughout the canopies. Net ecosystem emission rates were inversely related to foliar density which influenced the extinction of light and the acetaldehyde compensation point in the canopy. This is supported by branch level studies revealing much higher compensation points in the light than in the dark for poplar (Populus deltoides) and holly oak (Quercus ilex) implying a higher light/temperature sensitivity for acetaldehyde production relative to consumption. The view of stomata as the major pathway for acetaldehyde exchange is supported by strong linear correlations between branch transpiration rates and acetaldehyde exchange velocities for both species. In addition, natural abundance carbon isotope analysis of gas-phase acetaldehyde during poplar branch fumigation experiments revealed a significant kinetic isotope effect of 5.1±0.3‰, associated with the uptake of acetaldehyde. Similar experiments with dry dead poplar leaves showed no fractionation or uptake of acetaldehyde, confirming that this is only a property of living leaves. We suggest that acetaldehyde belongs to a potentially large list of plant metabolites where stomatal conductance can exert long term control over both emission and uptake rates due to the presence of both source(s) and sink(s) within the leaf which strongly buffer large changes in concentrations in the substomatal airspace due to changes in stomatal conductance. We conclude that the exchange of acetaldehyde between plant canopies and the atmosphere is fundamentally controlled by ambient acetaldehyde concentrations, stomatal conductance, and the acetaldehyde compensation point.

  7. Uptake and physiological response of crop plants irrigated with water containing RDX and TNT

    SciTech Connect

    Simini, M.; Checkai, R.T.

    1995-12-31

    Regulatory agencies have expressed concern about possible bioconcentration of TNT (2,4,6-trinitrotoluene) and RDX (cyclotrimethylenetrinitramine) in food and forage crops irrigated with contaminated groundwater. Field and home-garden crops grown in site-collected soil were irrigated with water containing RDX and TNT to simulate field conditions at Cornhusker Army Ammunition Plant (CAAP), Nebraska. Pots were watered in an environment-controlled greenhouse to field capacity throughout the life-cycle of each crop with 2, 20, and 100 ppb RDX; 2, 100, and 800 ppb TNT; 100 ppb RDX + 800 ppb TNT; or uncontaminated water in response to evapo-transpirative demand. Uptake of RDX in lettuce leaves, corn stover, and alfalfa shoots was positively correlated with treatment level, however, concentrations of RDX in these crops were generally equal to or below soil loading concentrations. RDX was not significantly (p = 0.05) taken up into tomato fruit, bush bean seeds and pods, radish roots, and soybean seeds. TNT was not significantly take up into tissues of any of the crops analyzed in this study. Yield and biomass of tomato fruit, bush bean fruit, corn stover, and soybean seeds were significantly (p = 0.05) less when irrigated with the RDX + TNT treatment compared to controls. Lettuce leaf, radish root, and alfalfa shoot yield and biomass were unaffected by treatment level. For site-specific criteria used in this study, RDX and TNT did not bioconcentrate in edible plant tissues. This is the first controlled study to investigate uptake of RDX and TNT in crops irrigated with water containing explosives concentrations commonly found in contaminated groundwater.

  8. Physiological and biochemical effect of neem and other Meliaceae plants secondary metabolites against Lepidopteran insects

    PubMed Central

    Senthil-Nathan, Sengottayan

    2013-01-01

    This review described the physiological and biochemical effects of various secondary metabolites from Meliaceae against major Lepidopteran insect pest including, Noctuidae and Pyralidae. The biochemical effect of major Meliaceae secondary metabolites were discussed more in this review. Several enzymes based on food materials have critical roles in nutritional indices (food utilization) of the insect pest population. Several research work has been referred and the effect of Meliaceae secondary metabolites on feeding parameters of insects by demonstrating food consumption, approximate digestibility of consumed food, efficiency of converting the ingested food to body substance, efficiency of converting digested food to body substance and consumption index was reviewed in detail. Further how the digestive enzymes including a-Amylases, α and β-glucosidases (EC 3.2.1.1), lipases (EC 3.1.1) Proteases, serine, cysteine, and aspartic proteinases affected by the Meliaceae secondary metabolites was reviewed. Further effect of Meliaceae secondary metabolites on detoxifying enzymes have been found to react against botanical insecticides including general esterases (EST), glutathione S-transferase (GST) and phosphatases was reviewed. Alkaline phosphatase (ALP, E.C.3.1.3.1) and acid phosphatase (ACP, E.C.3.1.3.2) are hydrolytic enzymes, which hydrolyze phosphomonoesters under alkaline or acid conditions, respectively. These enzymes were affected by the secondary metabolites treatment. The detailed mechanism of action was further explained in this review. Acethylcholine esterase (AChE) is a key enzyme that terminates nerve impulses by catalyzing the hydrolysis of neurotransmitter, acetylcholine, in the nervous system of various organisms. How the AChE activity was altered by the Meliaceae secondary metabolites reviewed in detail. PMID:24391591

  9. Potential of the Sentinel-2 Red Edge Spectral Bands for Estimation of Eco-Physiological Plant Parameters

    NASA Astrophysics Data System (ADS)

    Malenovsky, Zbynek; Homolova, Lucie; Janoutova, Ruzena; Landier, Lucas; Gastellu-Etchegorry, Jean-Philippe; Berthelot, Beatrice; Huck, Alexis

    2016-08-01

    In this study we investigated importance of the space- borne instrument Sentinel-2 red edge spectral bands and reconstructed red edge position (REP) for retrieval of the three eco-physiological plant parameters, leaf and canopy chlorophyll content and leaf area index (LAI), in case of maize agricultural fields and beech and spruce forest stands. Sentinel-2 spectral bands and REP of the investigated vegetation canopies were simulated in the Discrete Anisotropic Radiative Transfer (DART) model. Their potential for estimation of the plant parameters was assessed through training support vector regressions (SVR) and examining their P-vector matrices indicating significance of each input. The trained SVR were then applied on Sentinel-2 simulated images and the acquired estimates were cross-compared with results from high spatial resolution airborne retrievals. Results showed that contribution of REP was significant for canopy chlorophyll content, but less significant for leaf chlorophyll content and insignificant for leaf area index estimations. However, the red edge spectral bands contributed strongly to the retrievals of all parameters, especially canopy and leaf chlorophyll content. Application of SVR on Sentinel-2 simulated images demonstrated, in general, an overestimation of leaf chlorophyll content and an underestimation of LAI when compared to the reciprocal airborne estimates. In the follow-up investigation, we will apply the trained SVR algorithms on real Sentinel-2 multispectral images acquired during vegetation seasons 2015 and 2016.

  10. [Effects of soil moisture content and light intensity on the plant growth and leaf physiological characteristics of squash].

    PubMed

    Du, She-ni; Bai, Gang-shuan; Liang, Yin-li

    2011-04-01

    A pot experiment with artificial shading was conducted to study the effects of soil moisture content and light intensity on the plant growth and leaf physiological characteristics of squash variety "Jingyingyihao". Under all test soil moisture conditions, 30% shading promoted the growth of "Jingyingyihao", with the highest yield at 70% - 80% soil relative moisture contents. 70% shading inhibited plant growth severely, only flowering and not bearing fruits, no economic yield produced. In all treatments, there was a similar water consumption trend, i. e., both the daily and the total water consumption decreased with increasing shading and decreasing soil moisture content. Among all treatments, 30% shading and 70% - 80% soil relative moisture contents had the highest water use efficiency (2.36 kg mm(-1) hm(-2)) and water output rate (1.57 kg mm(-1) hm(-2)). The net photosynthetic rate, transpiration rate, stomatal conductance, and chlorophyll content of squash leaves decreased with increasing shading, whereas the intercellular CO2 concentration was in adverse. The leaf protective enzyme activity and proline content decreased with increasing shading, and the leaf MAD content decreased in the order of 70% shading, natural radiation, and 30% shading. Under the three light intensities, the change characteristics of squash leaf photosynthesis, protective enzyme activity, and proline and MAD contents differed with the increase of soil relative moisture content.

  11. [Physiological responses of cotton plant to fertlizer nitrogen at flowering and boll-forming stages under soil drought].

    PubMed

    Liu, Rui-Xian; Guo, Wen-Qi; Chen, Bing-Lin; Zhou, Zhi-Guo

    2008-07-01

    With pot culture, the physiological responses of cotton plant to fertilizer nitrogen at flowering and boll-forming stages were studied under soil drought and after re-watering. The results showed that under soil drought, the net photosynthetic rate (Pn) and transpiration rate (Tr) declined rapidly with decreasing soil relative water content (SRWC). At the early stage of soil drought, owing to the declining degree of Tr was greater than that of Pn, the WUE had an increasing trend; but after then, the WUE decreased with declining SRWC and Pn. Soil drought altered the diurnal patters of Pn and Tr, i.e., decreased continuously from 8:00 to 16:00, while in CK, their peak values appeared at 10:00-11:00 and 12:00, respectively. The diurnal patterns of WUE in drought treatment and CK were the same, i.e., decreased first and increased then, with the bottom appeared at 12:00. Under soil drought, the Pn and Tr decreased with increasing fertilizer nitrogen level, while WUE was in adverse. After re-watering, the diurnal patterns of Pn, Tr and WUE were similar to CK, but their values were smaller than CK, especially under nitrogen application. It was suggested that under soil drought, nitrogen fertilization could be helpful to the increase of water use efficiency, but decreased the photosynthesis of cotton plant at its flowering and boll-forming stages.

  12. Phylogeny, physiology and distribution of 'Candidatus Microthrix calida', a new Microthrix species isolated from industrial activated sludge wastewater treatment plants.

    PubMed

    Levantesi, Caterina; Rossetti, Simona; Thelen, Karin; Kragelund, Caroline; Krooneman, Janneke; Eikelboom, Dick; Nielsen, Per Halkjaer; Tandoi, Valter

    2006-09-01

    Twelve strains of filamentous bacteria morphologically identified as 'Microthrix parvicella' were isolated from industrial activated sludge wastewater treatment plants. 16S rRNA gene sequences analysis showed that these strains were all closely related to 'Candidatus Microthrix parvicella'. Six of them, however, had a 16S rRNA gene similarity of only 95.7% and 96.7% to 'Candidatus Microthrix parvicella' suggesting the presence of a new species. The name 'Candidatus Microthrix calida' is proposed for this new microorganism. The physiological properties of these six isolates supported the description of a new taxon. The 'Candidatus Microthrix calida' strains produced thin filaments (0.3-0.7 microm diameter), they did not grow on the media supporting the growth of 'Candidatus Microthrix parvicella' and could be cultivated at higher temperature (up to 36.5 degrees C). Preliminary data on substrate uptake were obtained by microautoradiography on pure culture. Two new fluorescence in situ hybridization (FISH) probes, Mpa-T1-1260 specific for 'Candidatus Microthrix calida' and Mpa-all-1410 targeting both Microthrix species, were designed. The presence of Microthrix spp. was investigated in 114 activated sludge plants. 'Microthrix parvicella' morphotype was detected in 23% of the analysed samples and FISH analysis revealed that 'Candidatus Microthrix calida' was present in 5% of them. The remaining 'M. parvicella' filaments were positive with probe Mpa-all-1410 but could not all be identified as 'Candidatus Microthrix parvicella' suggesting the presence of more hitherto undescribed biodiversity within this morphotype.

  13. A new cadmium reduction device for the microplate determination of nitrate in water, soil, plant tissue, and physiological fluids.

    PubMed

    Crutchfield, James D; Grove, John H

    2011-01-01

    A reusable catalytic reductor consisting of 96 copperized-cadmium pins attached to a microplate lid was developed to simultaneously reduce nitrate (NO3-) to nitrite (NO2-) in all wells of a standard microplate. The resulting NO2- is analyzed colorimetrically by the Griess reaction using a microplate reader. Nitrate data from groundwater samples analyzed using the new device correlated well with data obtained by ion chromatography (r2 = 0.9959). Soil and plant tissue samples previously analyzed for NO3- in an interlaboratory validation study sponsored by the Soil Science Society of America were also analyzed using the new technique. For the soil sample set, the data are shown to correlate well with the other methods used (r2 = 0.9976). Plant data correlated less well, especially for samples containing low concentrations of NO3-. Reasons for these discrepancies are discussed, and new techniques to increase the accuracy of the analysis are explored. In addition, a method is presented for analyzing NO3- in physiological fluids (blood serum and urine) after matrix modification with Somogyi's reagent. A protocol for statistical validation of data when analyzing samples with complex matrixes is also established. The simplicity, adaptability, and low cost of the device indicate its potential for widespread application.

  14. The signature of seeds in resurrection plants: a molecular and physiological comparison of desiccation tolerance in seeds and vegetative tissues.

    PubMed

    Illing, Nicola; Denby, Katherine J; Collett, Helen; Shen, Arthur; Farrant, Jill M

    2005-11-01

    Desiccation-tolerance in vegetative tissues of angiosperms has a polyphyletic origin and could be due to 1) appropriation of the seed-specific program of gene expression that protects orthodox seeds against desiccation, and/or 2) a sustainable version of the abiotic stress response. We tested these hypotheses by comparing molecular and physiological data from the development of orthodox seeds, the response of desiccation-sensitive plants to abiotic stress, and the response of desiccation-tolerant plants to extreme water loss. Analysis of publicly-available gene expression data of 35 LEA proteins and 68 anti-oxidant enzymes in the desiccation-sensitive Arabidopsis thaliana identified 13 LEAs and 4 anti-oxidants exclusively expressed in seeds. Two (a LEA6 and 1-cys-peroxiredoxin) are not expressed in vegetative tissues in A. thaliana, but have orthologues that are specifically activated in desiccating leaves of Xerophyta humilis. A comparison of antioxidant enzyme activity in two desiccation-sensitive species of Eragrostis with the desiccation-tolerant E. nindensis showed equivalent responses upon initial dehydration, but activity was retained at low water content in E. nindensis only. We propose that these antioxidants are housekeeping enzymes and that they are protected from damage in the desiccation-tolerant species. Sucrose is considered an important protectant against desiccation in orthodox seeds, and we show that sucrose accumulates in drying leaves of E. nindensis, but not in the desiccation-sensitive Eragrostis species. The activation of "seed-specific" desiccation protection mechanisms (sucrose accumulation and expression of LEA6 and 1-cys-peroxiredoxin genes) in the vegetative tissues of desiccation-tolerant plants points towards acquisition of desiccation tolerance from seeds.

  15. A Physiological Neural Controller of a Muscle Fiber Oculomotor Plant in Horizontal Monkey Saccades

    PubMed Central

    Enderle, John D.

    2014-01-01

    A neural network model of biophysical neurons in the midbrain is presented to drive a muscle fiber oculomotor plant during horizontal monkey saccades. Neural circuitry, including omnipause neuron, premotor excitatory and inhibitory burst neurons, long lead burst neuron, tonic neuron, interneuron, abducens nucleus, and oculomotor nucleus, is developed to examine saccade dynamics. The time-optimal control strategy by realization of agonist and antagonist controller models is investigated. In consequence, each agonist muscle fiber is stimulated by an agonist neuron, while an antagonist muscle fiber is unstimulated by a pause and step from the antagonist neuron. It is concluded that the neural network is constrained by a minimum duration of the agonist pulse and that the most dominant factor in determining the saccade magnitude is the number of active neurons for the small saccades. For the large saccades, however, the duration of agonist burst firing significantly affects the control of saccades. The proposed saccadic circuitry establishes a complete model of saccade generation since it not only includes the neural circuits at both the premotor and motor stages of the saccade generator, but also uses a time-optimal controller to yield the desired saccade magnitude. PMID:24944832

  16. Some physiological aspects of nitrate reductase-deficient Nicotiana plumbaginifolia plants

    SciTech Connect

    Saux, C.; Morot-Gaudry, J.F.; Lemoine, Y.; Caboche, M.

    1986-04-01

    Chlorate-resistant Nicotiana plumbaginifolia (cv. Viviani) mutants were found to be defective in the nitrate reductase apoprotein (NR/sup -/ nia). Because they could not grow with nitrate as sole nitrogen source, they were cultivated as graftings on wild type Nicotiana tabacum. The grafts of NR/sup -/ plants were found to contain less malate but more amino acids, sugars and starch than the wild type. Moreover they were chlorotic, with a slight increase of the proportion of LH Chl a/b protein complexes and they exhibited a lowering of the efficiency of energy transfer between the light-harvesting complexes and the active centers. After /sup 14/CO/sub 2/ pulse and chase experiments. The total /sup 14/C incorporation of the mutant leaves was approximately 20% of that of the control. The NR/sup -/ leaves mainly accumulated /sup 14/C in the whole intermediates of the Calvin-cycle and in sucrose. In the most deficient NR leaves, chloroplasts were stuffed with large starch inclusions disorganizing the lamellar system.

  17. Effect of soil salinity on physiological characteristics of functional leaves of cotton plants.

    PubMed

    Zhang, Lei; Zhang, Guowei; Wang, Youhua; Zhou, Zhiguo; Meng, Yali; Chen, Binglin

    2013-03-01

    This study analyzes the effects of soil salinity on fatty acid composition, antioxidative enzyme activity, lipid peroxidation, and photosynthesis in functional leaves during the flowering and boll-forming stages of two cotton cultivars, namely, CCRI-44 (salt-tolerant) and Sumian 12 (salt-sensitive), grown under different soil salinity conditions. Saturated (C16:0 and C18:0) and unsaturated fatty acid (FA) contents (C18:1), as well as superoxide dismutase activity increased, whereas high-unsaturated FA (C18:2 and C18:3) decreased, with the increase in soil salinity. The production of malondialdehyde increased with increasing lipoxygenase (LOX) activity, indicating that LOX catalyzed FA peroxidation under salt stress. Soil salinity had no significant effect on catalase (CAT) and peroxidases (POD) activity in the salt-sensitive cultivar Sumian 12, but significantly increased CAT and POD activities in the salt-tolerant cultivar CCRI-44. Net photosynthesis and stomatal conductance of the cotton cultivars decreased in response to salt stress; however, CCRI-44 showed a smaller reduction in photosynthesis than Sumian 12. The results indicated that stomatal apparatus limited leaf photosynthetic capacity in the salinity-treated plants of both cultivars. The net photosynthetic rate, maximum photochemical efficiency, and photochemical quantum yield of the cotton functional leaves showed positive correlation with double-bond index (DBI). These results suggested that salt stress caused DBI reduction and decreased the photochemical conversion efficiency of solar radiation and, thereby resulting in lower net photosynthetic rates.

  18. An update: improvements in imaging perfluorocarbon-mounted plant leaves with implications for studies of plant pathology, physiology, development and cell biology.

    PubMed

    Littlejohn, George R; Mansfield, Jessica C; Christmas, Jacqueline T; Witterick, Eleanor; Fricker, Mark D; Grant, Murray R; Smirnoff, Nicholas; Everson, Richard M; Moger, Julian; Love, John

    2014-01-01

    Plant leaves are optically complex, which makes them difficult to image by light microscopy. Careful sample preparation is therefore required to enable researchers to maximize the information gained from advances in fluorescent protein labeling, cell dyes and innovations in microscope technologies and techniques. We have previously shown that mounting leaves in the non-toxic, non-fluorescent perfluorocarbon (PFC), perfluorodecalin (PFD) enhances the optical properties of the leaf with minimal impact on physiology. Here, we assess the use of the PFCs, PFD, and perfluoroperhydrophenanthrene (PP11) for in vivo plant leaf imaging using four advanced modes of microscopy: laser scanning confocal microscopy (LSCM), two-photon fluorescence microscopy, second harmonic generation microscopy, and stimulated Raman scattering (SRS) microscopy. For every mode of imaging tested, we observed an improved signal when leaves were mounted in PFD or in PP11, compared to mounting the samples in water. Using an image analysis technique based on autocorrelation to quantitatively assess LSCM image deterioration with depth, we show that PP11 outperformed PFD as a mounting medium by enabling the acquisition of clearer images deeper into the tissue. In addition, we show that SRS microscopy can be used to image PFCs directly in the mesophyll and thereby easily delimit the "negative space" within a leaf, which may have important implications for studies of leaf development. Direct comparison of on and off resonance SRS micrographs show that PFCs do not to form intracellular aggregates in live plants. We conclude that the application of PFCs as mounting media substantially increases advanced microscopy image quality of living mesophyll and leaf vascular bundle cells.

  19. Plant Physiological Effects on Summer Drought in the Western U.S

    NASA Astrophysics Data System (ADS)

    Felzer, B. S.; Cronin, T.; Kicklighter, D. W.; Schlosser, C. A.; Melillo, J. M.

    2009-12-01

    During the last half-century, large areas of the Western U.S., especially the intermountain interior, have experienced increasing drought. IPCC AR4 projections for a range of scenarios consistently show less runoff and soil moisture in the Southwestern U.S. and central Plains indicating that these drought trends will continue into the future. More persistent droughts in these areas are the result of increased evapotranspiration as well as reduced precipitation in certain locations resulting from a shift in storm tracks. In the West there is also predicted to be a seasonal shift, with more runoff in the early spring and less in the late summer due to a larger rain/snow ratio and earlier snowmelt. Some of the sophisticated land surface models used for these projections include variable stomatal resistance, but none include the effects of nitrogen limitation and ozone damage on transpiration. Elevated CO2 is known to suppress stomatal conductance, thereby increasing plant water use efficiency and increasing runoff. By reducing photosynthesis, nitrogen limitation and exposure to ozone also reduce transpiration, increasing runoff. To explore how these feedbacks may influence Western hydrology, we use downscaled climate scenarios from the Coupled Model Intercomparison Project (CMIP) to capture the topographic variability of the West and force a biogeochemical model, TEM-Hydro for land cover types particular to the West, including temperate and boreal forests, xeric and mesic shrublands, and grasslands. We will report the effects of changing climate, elevated CO2, nitrogen limitation, and ozone damage on runoff, together and separately, and compare against our results from eastern U.S. forests, which show as much as a 6% increase in runoff due to CO2 and another 11% increase in runoff due to N-limitation and ozone.

  20. Physiological integration modifies δ15N in the clonal plant Fragaria vesca, suggesting preferential transport of nitrogen to water-stressed offspring

    PubMed Central

    Roiloa, S. R.; Antelo, B.; Retuerto, R.

    2014-01-01

    Background and Aims One of the most striking attributes of clonal plants is their capacity for physiological integration, which enables movement of essential resources between connected ramets. This study investigated the capacity of physiological integration to buffer differences in resource availability experienced by ramets of the clonal wild strawberry plant, Fragaria vesca. Specifically, a study was made of the responses of connected and severed offspring ramets growing in environments with different water availability conditions (well watered or water stressed) and nitrogen forms (nitrate or ammonium). Methods The experimental design consisted of three factors, ‘integration’ (connected, severed) ‘water status’ (well watered, water stressed) and ‘nitrogen form’ (nitrate, ammonium), applied in a pot experiment. The effects of physiological integration were studied by analysing photochemical efficiency, leaf spectral reflectance, photosynthesis and carbon and nitrogen isotope discrimination, the last of which has been neglected in previous studies. Key Results Physiological integration buffered the stress caused by water deprivation. As a consequence, survival was improved in water-stressed offspring ramets that remained connected to their parent plants. The nitrogen isotope composition (δ15N) values in the connected water-stressed ramets were similar to those in ramets in the ammonium treatment; however, δ15N values in connected well-watered ramets were similar to those in the nitrate treatment. The results also demonstrated the benefit of integration for offspring ramets in terms of photochemical activity and photosynthesis. Conclusions This is the first study in which carbon and nitrogen isotopic discrimination has been used to detect physiological integration in clonal plants. The results for nitrogen isotope composition represent the first evidence of preferential transport of a specific form of nitrogen to compensate for stressful conditions

  1. Exploring Relationships Between Vegetation Reflectance and Plant Physiological Parameters on Arctic Wet Sedge Tundra

    NASA Astrophysics Data System (ADS)

    Boelman, N.; Griffin, K.; Stieglitz, M.; Shaver, G. R.; Gamon, J. A.

    2001-12-01

    have higher photosynthetic rates, which enable the plants to produce more blue light receptors (carotenoids and zeaxanthin) in order for them to take full advantage of the shortness and low light intensity that is characteristic of the Arctic growing season.

  2. Arbuscular Mycorrhizal Fungus Species Dependency Governs Better Plant Physiological Characteristics and Leaf Quality of Mulberry (Morus alba L.) Seedlings

    PubMed Central

    Shi, Song-Mei; Chen, Ke; Gao, Yuan; Liu, Bei; Yang, Xiao-Hong; Huang, Xian-Zhi; Liu, Gui-Xi; Zhu, Li-Quan; He, Xin-Hua

    2016-01-01

    Understanding the synergic interactions between arbuscular mycorrhizal fungi (AMF) and its host mulberry (Morus alba L.), an important perennial multipurpose plant, has theoretical and practical significance in mulberry plantation, silkworm cultivation, and relevant textile industry. In a greenhouse study, we compared functional distinctions of three genetically different AMF species (Acaulospora scrobiculata, Funneliformis mosseae, and Rhizophagus intraradices) on physiological and growth characteristics as well as leaf quality of 6-month-old mulberry seedlings. Results showed that mulberry was AMF-species dependent, and AMF colonization significantly increased shoot height and taproot length, stem base and taproot diameter, leaf and fibrous root numbers, and shoot and root biomass production. Meanwhile, leaf chlorophyll a or b and carotenoid concentrations, net photosynthetic rate, transpiration rate and stomatal conductance were generally significantly greater, while intercellular CO2 concentration was significantly lower in AMF-inoculated seedlings than in non-AMF-inoculated counterparts. These trends were also generally true for leaf moisture, total nitrogen, all essential amino acids, histidine, proline, soluble protein, sugar, and fatty acid as they were significantly increased under mycorrhization. Among these three tested AMFs, significantly greater effects of AMF on above-mentioned mulberry physiological and growth characteristics ranked as F. mosseae > A. scrobiculata > R. intraradices, whilst on mulberry leaf quality (e.g., nutraceutical values) for better silkworm growth as F. mosseae ≈A. scrobiculata > R. intraradices. In conclusion, our results showed that greater mulberry biomass production, and nutritional quality varied with AMF species or was AMF-species dependent. Such improvements were mainly attributed to AMF-induced positive alterations of mulberry leaf photosynthetic pigments, net photosynthetic rate, transpiration rate, and N

  3. [Effects of biochar on the micro-ecology of tobacco-planting soil and physiology of flue-cured tobacco].

    PubMed

    Chen, Yi; Chen, Wei; Lin, Ye-chun; Cheng, Jian-zhong; Pan, Wen-jie

    2015-12-01

    Biochar is one of the research hotspots in the field of the agroforestry waste utilization. A field experiment was carried out to investigate the effects of different amounts of tobacco stem biochar (0, 1, 10, 50 t · hm⁻²) on soil micro-ecology and physiological properties of flue-cured tobacco. The results showed that soil water content (SWC) increased at all tobacco growth stages as the amounts of biochar applications increased. There were significant differences of SWC between the treatment of 50 t · hm⁻² and other treatments at the period of tobacco vigorous growth. As the application of biochar increased, the total soil porosity and capillary porosity increased, while soil bacteria, actinomyces, fungi amount increased firstly and then decreased. The amount of soil bacteria, actinomyces, fungi reached the maximum at the treatment of 10 t · hm⁻². Soil respiration rate (SRR) at earlier stage increased with the increase of biochar application. Compared with the control, SSR under biochar treatments increased by 7.9%-36.9%, and there were significant differences of SRR between high biochar application treatments (50 t · hm⁻² and 10 t · hm⁻²) and the control. Biochar improved leaf water potential, carotenoid and chlorophyll contents. Meanwhile, the dry mass of root, shoot and total dry mass under biochar application were higher than that of the control. These results indicated that the biochar played active roles in improving tobacco-planting soil micro-ecology and regulating physiological properties of flue-cured tobacco.

  4. Arbuscular Mycorrhizal Fungus Species Dependency Governs Better Plant Physiological Characteristics and Leaf Quality of Mulberry (Morus alba L.) Seedlings.

    PubMed

    Shi, Song-Mei; Chen, Ke; Gao, Yuan; Liu, Bei; Yang, Xiao-Hong; Huang, Xian-Zhi; Liu, Gui-Xi; Zhu, Li-Quan; He, Xin-Hua

    2016-01-01

    Understanding the synergic interactions between arbuscular mycorrhizal fungi (AMF) and its host mulberry (Morus alba L.), an important perennial multipurpose plant, has theoretical and practical significance in mulberry plantation, silkworm cultivation, and relevant textile industry. In a greenhouse study, we compared functional distinctions of three genetically different AMF species (Acaulospora scrobiculata, Funneliformis mosseae, and Rhizophagus intraradices) on physiological and growth characteristics as well as leaf quality of 6-month-old mulberry seedlings. Results showed that mulberry was AMF-species dependent, and AMF colonization significantly increased shoot height and taproot length, stem base and taproot diameter, leaf and fibrous root numbers, and shoot and root biomass production. Meanwhile, leaf chlorophyll a or b and carotenoid concentrations, net photosynthetic rate, transpiration rate and stomatal conductance were generally significantly greater, while intercellular CO2 concentration was significantly lower in AMF-inoculated seedlings than in non-AMF-inoculated counterparts. These trends were also generally true for leaf moisture, total nitrogen, all essential amino acids, histidine, proline, soluble protein, sugar, and fatty acid as they were significantly increased under mycorrhization. Among these three tested AMFs, significantly greater effects of AMF on above-mentioned mulberry physiological and growth characteristics ranked as F. mosseae > A. scrobiculata > R. intraradices, whilst on mulberry leaf quality (e.g., nutraceutical values) for better silkworm growth as F. mosseae ≈A. scrobiculata > R. intraradices. In conclusion, our results showed that greater mulberry biomass production, and nutritional quality varied with AMF species or was AMF-species dependent. Such improvements were mainly attributed to AMF-induced positive alterations of mulberry leaf photosynthetic pigments, net photosynthetic rate, transpiration rate, and N

  5. Effects of a ladle furnace slag added to soil on morpho-physiological and biochemical parameters of Amaranthus paniculatus L. plants.

    PubMed

    Pietrini, Fabrizio; Iori, Valentina; Beone, Teresa; Mirabile, Daphne; Zacchini, Massimo

    2017-05-05

    Industrial slag from steelwork activities is considered a by-product by the EU legislation and it can be used for civil construction. In this work, an experiment in a greenhouse was conducted over a 6-week period to investigate the effect of soil enrichment with ladle furnace slag on morpho-physiological parameters of Amaranthus paniculatus L. plants. Results showed that the addition of 5% (w/w) slag to soil did not alter the plant growth, highlighting a high tolerance to this slag concentration. Contrarily, plants cultivated in a soil with 10% (w/w) slag showed a marked reduction both in growth and biometric parameters. Moreover, plants grown on a slag-rich soil (20% w/w) highlighted a very low survival rate. This behaviour was confirmed by the biochemical and physiological investigations on chlorophyll a and b content, gas exchange and chlorophyll fluorescence analyses. Metal(loid)s determination showed the accumulation of Ni, Se, Sn, As, Sb and Cd in 10% slag-treated plants, while revealed an increase in Ni, Cd, As and Pb in 5% slag-treated plants. Results are discussed highlighting the profitability of the cultivation of Amaranthus plants on slag enriched soil, as this plant species is largely used both as feedstock for energy production and for environmental restoration.

  6. Physiological acclimation strategies of riparian plants to environment change in the delta of the Tarim River, China

    NASA Astrophysics Data System (ADS)

    Ruan, Xiao; Wang, Qiang; Pan, Cun-De; Chen, Ya-Ning; Jiang, Hao

    2009-06-01

    The occurrence and development of riparian forests, which were mainly dominated by mesophytes species related closely with surface water. Since there was no water discharged to the lower reaches of Tarim River in the past three decade years, the riparian forests degrade severely. The groundwater table, the saline content of the groundwater, as well as the content of free proline, soluble sugars, plant endogenous hormones (abscisic acid (ABA), and cytokinins (CTK)) of the leaves and relative rates of sap flow of the Populus euphratica Oliv. (arbor species), Tamarix ramosissima Ldb. (bush species), and Apocynum venetum L. (herb species) were monitored and analyzed at the lower reaches of the Tarim River in the study area where five positions on a transect were fixed at 100 m intervals along a sampling direction from riverbank to the sand dunes before and after water release. The physiological responses and acclimation strategies of three species to variations in water and salinity stress were discussed. It was found that A. venetum population recovered to groundwater table ranging from -1.73 to -3.56 m, and when exposed to saline content of the groundwater ranging from 36.59 to 93.48 m mol/L; P. euphratica appeared to be more sensitive to the elevation of groundwater table than the A. venetum and T. ramosissima at groundwater table ranging from -5.08 to -5.80 m, and when exposed to saline content of the groundwater ranging from 42.17 to 49.55 m mol/L. T. ramosissima tended to be the best candidate species for reclamation in this hyper-arid area because it responded to groundwater table ranging from -1.73 to -7.05 m, and when exposed to saline content of the groundwater ranging from 36.59 to 93.48 m mol/L. These results explained the distribution patterns of desert vegetation in the lower reaches of the Tarim River. Understanding the relationships among ecological factors variables, physiological response and acclimation strategies of plant individuals could provide

  7. Exogenously Applied Plant Growth Regulators Enhance the Morpho-Physiological Growth and Yield of Rice under High Temperature

    PubMed Central

    Fahad, Shah; Hussain, Saddam; Saud, Shah; Hassan, Shah; Ihsan, Zahid; Shah, Adnan N.; Wu, Chao; Yousaf, Muhammad; Nasim, Wajid; Alharby, Hesham; Alghabari, Fahad; Huang, Jianliang

    2016-01-01

    A 2-year experiment was conducted to ascertain the effects of exogenously applied plant growth regulators (PGR) on rice growth and yield attributes under high day (HDT) and high night temperature (HNT). Two rice cultivars (IR-64 and Huanghuazhan) were subjected to temperature treatments in controlled growth chambers and four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA), and triazoles (Tr) were applied. High temperature severely affected rice morphology, and also reduced leaf area, above-, and below-ground biomass, photosynthesis, and water use efficiency, while increased the leaf water potential of both rice cultivars. Grain yield and its related attributes except number of panicles, were reduced under high temperature. The HDT posed more negative effects on rice physiological attributes, while HNT was more detrimental for grain formation and yield. The Huanghuazhan performed better than IR-64 under high temperature stress with better growth and higher grain yield. Exogenous application of PGRs was helpful in alleviating the adverse effects of high temperature. Among PGR combinations, the Vc+Ve+MejA+Br was the most effective treatment for both cultivars under high temperature stress. The highest grain production by Vc+Ve+MejA+Br treated plants was due to enhanced photosynthesis, spikelet fertility and grain filling, which compensated the adversities of high temperature stress. Taken together, these results will be of worth for further understanding the adaptation and survival mechanisms of rice to high temperature and will assist in developing heat-resistant rice germplasm in future. PMID:27625658

  8. To concentrate or ventilate? Carbon acquisition, isotope discrimination and physiological ecology of early land plant life forms.

    PubMed

    Meyer, Moritz; Seibt, Ulli; Griffiths, Howard

    2008-08-27

    A comparative study has been made of the photosynthetic physiological ecology and carbon isotope discrimination characteristics for modern-day bryophytes and closely related algal groups. Firstly, the extent of bryophyte distribution and diversification as compared with more advanced land plant groups is considered. Secondly, measurements of instantaneous carbon isotope discrimination (Delta), photosynthetic CO(2) assimilation and electron transport rates were compared during the drying cycles. The extent of surface diffusion limitation (when wetted), internal conductance and water use efficiency (WUE) at optimal tissue water content (TWC) were derived for liverworts and a hornwort from contrasting habitats and with differing degrees of thallus ventilation (as intra-thalline cavities and internal airspaces). We also explore how the operation of a biophysical carbon-concentrating mechanism (CCM) tempers isotope discrimination characteristics in two other hornworts, as well as the green algae Coleochaete orbicularis and Chlamydomonas reinhardtii. The magnitude of Delta was compared for each life form over a drying curve and used to derive the surface liquid-phase conductance (when wetted) and internal conductance (at optimal TWC). The magnitude of external and internal conductances, and WUE, was higher for ventilated, compared with non-ventilated, liverworts and hornworts, but the values were similar within each group, suggesting that both factors have been optimized for each life form. For the hornworts, leakiness of the CCM was highest for Megaceros vincentianus and C. orbicularis (approx. 30%) and, at 5%, lowest in C. reinhardtii grown under ambient CO2 concentrations. Finally, evidence for the operation of a CCM in algae and hornworts is considered in terms of the probable role of the chloroplast pyrenoid, as the origins, structure and function of this enigmatic organelle are explored during the evolution of land plants.

  9. A self-referencing biosensor for real-time monitoring of physiological ATP transport in plant systems.

    PubMed

    Vanegas, Diana C; Clark, Greg; Cannon, Ashley E; Roux, Stanley; Chaturvedi, Prachee; McLamore, Eric S

    2015-12-15

    The objective of this study was to develop a self-referencing electrochemical biosensor for the direct measurement of ATP flux into the extracellular matrix by living cells/organisms. The working mechanism of the developed biosensor is based on the activity of glycerol kinase and glycerol-3-phosphate oxidase. A stratified bi-enzyme nanocomposite was created using a protein-templated silica sol gel encapsulation technique on top of graphene-modified platinum electrodes. The biosensor exhibited excellent electrochemical performance with a sensitivity of 2.4±1.8 nA/µM, a response time of 20±13 s and a lower detection limit of 1.3±0.7 nM. The self-referencing biosensor was used to measure exogenous ATP efflux by (i) germinating Ceratopteris spores and (ii) growing Zea mays L. roots. This manuscript demonstrates the first development of a non-invasive ATP micro-biosensor for the direct measurement of eATP transport in living tissues. Before this work, assays of eATP have not been able to record the temporally transient movement of ATP at physiological levels (nM and sub-nM). The method demonstrated here accurately measured [eATP] flux in the immediate vicinity of plant cells. Although these proof of concept experiments focus on plant tissues, the technique developed herein is applicable to any living tissue, where nanomolar concentrations of ATP play a critical role in signaling and development. This tool will be invaluable for conducting hypothesis-driven life science research aimed at understanding the role of ATP in the extracellular environment.

  10. The effect of lichen-dominated biological soil crusts on growth and physiological characteristics of three plant species in a temperate desert of northwest China.

    PubMed

    Zhuang, W W; Serpe, M; Zhang, Y M

    2015-11-01

    Biocrusts (biological soil crusts) cover open spaces between vascular plants in most arid and semi-arid areas. Information on effects of biocrusts on seedling growth is controversial, and there is little information on their effects on plant growth and physiology. We examined impacts of biocrusts on growth and physiological characteristics of three habitat-typical plants, Erodium oxyrhynchum, Alyssum linifolium and Hyalea pulchella, growing in the Gurbantunggut Desert, northwest China. The influence of biocrusts on plant biomass, leaf area, leaf relative water content, photosynthesis, maximum quantum efficiency of PSII (F(v)/F(m)), chlorophyll, osmotic solutes (soluble sugars, protein, proline) and antioxidant enzymes (superoxide dismutase, catalase, peroxidase) was investigated on sites with or without biocrust cover. Biomass, leaf area, leaf water content, photosynthesis, F(v)/F(m) and chlorophyll content in crusted soils were higher than in uncrusted soils during early growth and lower later in the growth period. Soluble sugars, proline and antioxidant enzyme activity were always higher in crusted than in uncrusted soils, while soluble protein content was always lower. These findings indicate that biocrusts have different effects on these three ephemeral species during growth in this desert, primarily via effects on soil moisture, and possibly on soil nutrients. The influence of biocrusts changes during plant development: in early plant growth, biocrusts had either positive or no effect on growth and physiological parameters. However, biocrusts tended to negatively influence plants during later growth. Our results provide insights to explain why previous studies have found different effects of biocrusts on vascular plant growth.

  11. Observed and simulated effect of plant physiology and structure on land surface energy fluxes and soil conditions

    NASA Astrophysics Data System (ADS)

    Lu, Yen-Sen; Rihani, Jehan; Langensiepen, Matthias; Simmer, Clemens

    2016-04-01

    The parameterization of stomatal conductance and leaf area index (LAI) in land surface models largely influence simulated terrestrial system states. While stomatal conductance mainly controls transpiration, latent heat flux, and root-water-uptake, LAI impacts additionally the radiative energy exchange. Thus both affect canopy evaporation and transpiration and land surface energy and water fluxes as a whole. Common parameterizations of stomatal conductance follow either semi-mechanistic forms based on photosynthesis (Ball-Berry Type (BB)) or forms which consider environmental factors such as impact of light, temperature, humidity and soil moisture (Jarvis-Stewart Type (JS)). Both approaches differ also in the interpretation of humidity effects and light-use efficiency. While soil moisture plays an important role for root-water-uptake there is no clear conclusion yet about how soil moisture interacts with stomata activity. Values for LAI can be obtained from field measurements, satellite estimates or modelling and are used as an essential model input. While field measurements are very time consuming and only represent single points, satellite estimates may have biases caused by variable albedo and sensor limitations. Representing LAI within land surface models requires complex schemes in order to represent all processes contributing to plant growth. We use the Terrestrial System Modelling Platform (TerrSysMP) over the Rur watershed in Germany for studying the influence of plant physiology and structure on the state of the terrestrial system. The Transregional Collaborative Research Center 32 (TR32) extensively monitors this catchment for almost a decade. The land surface (CLM3.5) and the subsurface (ParFlow) modules of TerrSysMP are conditioned based on satellite-retrieved land cover and the soil map from FAO and forced with a high-resolution reanalysis by DWD. For studying the effect of plant physiology, the Ball-Berry-Leuning, and Jarvis-Stewart stomatal

  12. Arbuscular mycorrhizal symbiosis regulates physiology and performance of Digitaria eriantha plants subjected to abiotic stresses by modulating antioxidant and jasmonate levels.

    PubMed

    Pedranzani, H; Rodríguez-Rivera, M; Gutiérrez, M; Porcel, R; Hause, B; Ruiz-Lozano, J M

    2016-02-01

    This study evaluates antioxidant responses and jasmonate regulation in Digitaria eriantha cv. Sudafricana plants inoculated (AM) and non-inoculated (non-AM) with Rhizophagus irregularis and subjected to drought, cold, or salinity. Stomatal conductance, photosynthetic efficiency, biomass production, hydrogen peroxide accumulation, lipid peroxidation, antioxidants enzymes activities, and jasmonate levels were determined. Stomatal conductance and photosynthetic efficiency decreased in AM and non-AM plants under all stress conditions. However, AM plants subjected to drought, salinity, or non-stress conditions showed significantly higher stomatal conductance values. AM plants subjected to drought or non-stress conditions increased their shoot/root biomass ratios, whereas salinity and cold caused a decrease in these ratios. Hydrogen peroxide accumulation, which was high in non-AM plant roots under all treatments, increased significantly in non-AM plant shoots under cold stress and in AM plants under non-stress and drought conditions. Lipid peroxidation increased in the roots of all plants under drought conditions. In shoots, although lipid peroxidation decreased in AM plants under non-stress and cold conditions, it increased under drought and salinity. AM plants consistently showed high catalase (CAT) and ascorbate peroxidase (APX) activity under all treatments. By contrast, the glutathione reductase (GR) and superoxide dismutase (SOD) activity of AM roots was lower than that of non-AM plants and increased in shoots. The endogenous levels of cis-12-oxophytodienoc acid (OPDA), jasmonic acid (JA), and 12-OH-JA showed a significant increase in AM plants as compared to non-AM plants. 11-OH-JA content only increased in AM plants subjected to drought. Results show that D. eriantha is sensitive to drought, salinity, and cold stresses and that inoculation with AM fungi regulates its physiology and performance under such conditions, with antioxidants and jasmonates being involved

  13. Plant Survival and Mortality during Drought Can be Mediated by Co-occurring Species' Physiological and Morphological Traits: Results from a Model

    NASA Astrophysics Data System (ADS)

    Tai, X.; Mackay, D. S.

    2015-12-01

    Interactions among co-occurring species are mediated by plant physiology, morphology and environment. Without proper mechanisms to account for these factors, it remains difficult to predict plant mortality/survival under changing climate. A plant ecophysiological model, TREES, was extended to incorporate co-occurring species' belowground interaction for water. We used it to examine the interaction between two commonly co-occurring species during drought experiment, pine (Pinus edulis) and juniper (Juniperus monosperma), with contrasting physiological traits (vulnerability to cavitation and leaf water potential regulation). TREES was parameterized and validated using field-measured plant physiological traits. The root architecture (depth, profile, and root area to leaf area ratio) of juniper was adjusted to see how root morphology could affect the survival/mortality of its neighboring pine under both ambient and drought conditions. Drought suppressed plant water and carbon uptake, as well increased the average percentage loss of conductivity (PLC). Pine had 59% reduction in water uptake, 48% reduction in carbon uptake, and 38% increase in PLC, while juniper had 56% reduction in water uptake, 50% reduction in carbon and 29% increase in PLC, suggesting different vulnerability to drought as mediated by plant physiological traits. Variations in juniper root architecture further mediated drought stress on pine, from negative to positive. Different juniper root architecture caused variations in response of pine over drought (water uptake reduction ranged 0% ~63%, carbon uptake reduction ranged 0% ~ 70%, and PLC increase ranged 2% ~ 91%). Deeper or more uniformly distributed roots of juniper could effectively mitigate stress experienced by pine. In addition, the total water and carbon uptake tended to increase as the ratio of root area to leaf area increased while PLC showed non-monotonic response, suggesting the potential trade-off between maximizing resource uptake and

  14. Linking chlorophyll fluorescence, hyperspectral reflectance and plant physiological responses to detect stress using the photochemical reflectance index (PRI) (Invited)

    NASA Astrophysics Data System (ADS)

    Naumann, J. C.; Young, D.; Anderson, J.

    2009-12-01

    The concept of using vegetation as sentinels to indicate natural or anthropogenic stress is not new and could potentially provide an ideal mechanism for large-scale detection. Advances in fluorescence spectroscopy and reflectance-derived fluorescence have made possible earlier detection of stress in plants, especially before changes in chlorophyll content are visible. Our studies have been used to fuse leaf fluorescence and reflectance characteristics to remotely sense and rapidly detect vegetation stress and terrain characteristics. Laboratory studies have indicated that light-adapted fluorescence (ΔF/F‧m) measurements have been successful in all experiments at detecting stress from flooding, salinity, drought, herbicide and TNT contamination prior to visible signs of damage. ΔF/F‧m was related to plant physiological status in natural stress conditions, as seen in the relationships with stomatal conductance and photosynthesis The photochemical reflectance index (PRI) and other reflectance ratios were effective at tracking changes in ΔF/F‧m at the leaf and canopy-level scales. At the landscape-level, chlorophyll fluorescence and airborne reflectance imagery were used to evaluate spatial variations in stress in the dominant shrub on a barrier island, Myrica cerifera, during a severe drought and compared to an extremely wet year. Measurements of relative water content and the water band index (WBI970) indicated that water stress did not vary across the island. In contrast, there were significant differences in tissue chlorides across sites. Using PRI we were able to detect salinity stress across the landscape. PRI did not differ between wet and dry years. There was a positive relationship between PRI and ΔF/F‧m for M. cerifera (r2 = 0.79). The normalized difference vegetation index (NDVI), the chlorophyll index (CI) and WBI970 were higher during the wet summer but varied little across the island. PRI was not significantly related to NDVI, suggesting that

  15. Differences in Copper Absorption and Accumulation between Copper-Exclusion and Copper-Enrichment Plants: A Comparison of Structure and Physiological Responses

    PubMed Central

    Fu, Lei; Chen, Chen; Wang, Bin; Zhou, Xishi; Li, Shuhuan; Guo, Pan; Shen, Zhenguo; Wang, Guiping; Chen, Yahua

    2015-01-01

    Differences in copper (Cu) absorption and transport, physiological responses and structural characteristics between two types of Cu-resistant plants, Oenothera glazioviana (Cu-exclusion type) and Elsholtzia haichowensis (Cu-enrichment type), were investigated in the present study. The results indicated the following: (1) After 50 μM Cu treatment, the Cu ratio in the xylem vessels of E. haichowensis increased by 60%. A Cu adsorption experiment indicated that O. glazioviana exhibited greater resistance to Cu, and Cu absorption and the shoot/root ratio of Cu were significantly lower in O. glazioviana than in E. haichowensis. (2) An analysis of the endogenous abscisic acid (ABA) variance and exogenous ABA treatment demonstrated that the ABA levels of both plants did not differ; exogenous ABA treatment clearly reduced Cu accumulation in both plants. (3) The leaf stomatal density of O. glazioviana was significantly less than that of E. haichowensis. Guard cells in E. haichowensis plants were covered with a thick cuticle layer, the epidermal hair was more numerous and longer, and the number of xylem conduits in the root was small. (4) The transpiration rate and the stomatal conductance of O. glazioviana were both significantly lower than those of E. haichowensis, regardless of whether the plants were treated with Cu. Taken together, these results indicate that the differences in the structural characteristics between these two plant species, particularly in the characteristics related to plant transpiration, are important factors that govern whether plants acquire or exclude Cu. PMID:26207743

  16. Differences in Copper Absorption and Accumulation between Copper-Exclusion and Copper-Enrichment Plants: A Comparison of Structure and Physiological Responses.

    PubMed

    Fu, Lei; Chen, Chen; Wang, Bin; Zhou, Xishi; Li, Shuhuan; Guo, Pan; Shen, Zhenguo; Wang, Guiping; Chen, Yahua

    2015-01-01

    Differences in copper (Cu) absorption and transport, physiological responses and structural characteristics between two types of Cu-resistant plants, Oenothera glazioviana (Cu-exclusion type) and Elsholtzia haichowensis (Cu-enrichment type), were investigated in the present study. The results indicated the following: (1) After 50 μM Cu treatment, the Cu ratio in the xylem vessels of E. haichowensis increased by 60%. A Cu adsorption experiment indicated that O. glazioviana exhibited greater resistance to Cu, and Cu absorption and the shoot/root ratio of Cu were significantly lower in O. glazioviana than in E. haichowensis. (2) An analysis of the endogenous abscisic acid (ABA) variance and exogenous ABA treatment demonstrated that the ABA levels of both plants did not differ; exogenous ABA treatment clearly reduced Cu accumulation in both plants. (3) The leaf stomatal density of O. glazioviana was significantly less than that of E. haichowensis. Guard cells in E. haichowensis plants were covered with a thick cuticle layer, the epidermal hair was more numerous and longer, and the number of xylem conduits in the root was small. (4) The transpiration rate and the stomatal conductance of O. glazioviana were both significantly lower than those of E. haichowensis, regardless of whether the plants were treated with Cu. Taken together, these results indicate that the differences in the structural characteristics between these two plant species, particularly in the characteristics related to plant transpiration, are important factors that govern whether plants acquire or exclude Cu.

  17. The decrease in the population of Gluconacetobacter diazotrophicus in sugarcane after nitrogen fertilization is related to plant physiology in split root experiments.

    PubMed

    Rodríguez-Andrade, Osvaldo; Fuentes-Ramírez, Luis E; Morales-García, Yolanda E; Molina-Romero, Dalia; Bustillos-Cristales, María R; Martínez-Contreras, Rebeca D; Muñoz-Rojas, Jesús

    2015-01-01

    It has been established that a decrease in the population of Gluconacetobacter diazotrophicus associated with sugarcane occurs after nitrogen fertilization. This fact could be due to a direct influence of NH(4)NO(3) on bacterial cells or to changes in plant physiology after fertilizer addition, affecting bacterial establishment. In this work, we observed that survival of G. diazotrophicus was directly influenced when 44.8mM of NH(4)NO(3) (640mgN/plant) was used for in vitro experiments. Furthermore, micropropagated sugarcane plantlets were inoculated with G. diazotrophicus and used for split root experiments, in which both ends of the system were fertilized with a basal level of NH(4)NO(3) (0.35mM; 10mgN/plant). Twenty days post inoculation (dpi) one half of the plants were fertilized with a high dose of NH(4)NO(3) (6.3mM; 180 mgN/plant) on one end of the system. This nitrogen level was lower than that directly affecting G. diazotrophicus cells; however, it caused a decrease in the bacterial population in comparison with control plants fertilized with basal nitrogen levels. The decrease in the population of G. diazotrophicus was higher in pots fertilized with a basal nitrogen level when compared with the corresponding end supplied with high levels of NH4NO3 (100dpi; 80 days post fertilization) of the same plant system. These observations suggest that the high nitrogen level added to the plants induce systemic physiological changes that affect the establishment of G. diazotrophicus.

  18. Wetland Plant Physiology Exhibits Controls on Carbon Sequestration Processes in a Restored Temperate Peatland of California, USA

    NASA Astrophysics Data System (ADS)

    Windham-Myers, L.; Byrd, K. B.; Khanna, S.; Miller, R.; Anderson, F.

    2011-12-01

    Wetland soils, especially peatlands, serve as the leading long-term sink of carbon (C) in the terrestrial biosphere, representing ~5% of global terrestrial ecosystem acreage but ~25% of total stored terrestrial organic C. While inhibition of microbial respiration rates is a necessary component of peat formation, plant processes regulate gross and net organic matter production (GPP and NPP) and microbial respiration in the rhizosphere. Recent work in a 14-year-old, 6-ha experimental wetland complex in the California's Sacramento-San Joaquin Delta has documented that continuous flooding at 25 cm depth can generate peat growth averaging 1 kg C m-2 y-1, and elevation gains approaching 4 cm y-1, 40-fold greater than historic rates tied to mean sea level rise (1mm y-1). To determine macrophyte controls on organic matter production and respiration in emergent marsh habitats, plant physiological processes were examined for 3 dominant species: hardstem bulrush (Schoenoplectus acutus), narrowleaf and broadleaf cattail (Typha angustifolia and T. latifolia). Leaf-level photosynthetic rates (GPP) were collected monthly with a LiCor 6400XT in May-September of 2010 and 2011 across a gradient of water residence time. GPP, stomatal conductance, photosynthetically active radiation (PAR), relative humidity and leaf temperatures were assessed from pre-dawn to solar-noon to assess light-use (LUE) and water-use efficiency (WUE) for carbon assimilation (A). CO2 levels (Ci) were regulated to generate A-Ci curves, indicating leaf capacity to assimilate recycled CO2. Porewater acetate concentrations and live root concentrations of ethanol and acetaldehyde were assayed seasonally in 2011 as relative indices of fermentative respiration. Plant species distribution, NPP and leaf-area indices (LAI) were calculated using allometric relationships, and used to scale-up leaf-level GPP estimates, as well as to ground-truth high-resolution CIR imagery, to compare NDVIs with recent hyperspectral data

  19. Morphological, physiological and anatomical traits of plant functional types in temperate grasslands along a large-scale aridity gradient in northeastern China

    PubMed Central

    Guo, Chengyuan; Ma, Linna; Yuan, Shan; Wang, Renzhong

    2017-01-01

    At the species level, plants can respond to climate changes by changing their leaf traits; however, there is scant information regarding the responses of morphological, physiological and anatomical traits of plant functional types (PFTs) to aridity. Herein, the leaf traits of five PFTs representing 17 plant species in temperate grasslands were examined along a large-scale aridity gradient in northeastern China. The results show that leaf thickness in shrubs, perennial grasses and forbs increased with heightened aridity. Trees increased soluble sugar content, but shrubs, perennials and annual grasses enhanced proline accumulation due to increasing aridity. Moreover, vessel diameter and stomatal index in shrubs and perennial grasses decreased with increasing aridity, but stomatal density and vascular diameter of five PFTs were not correlated with water availability. In conclusion, divergences in adaptive strategies to aridity among these PFTs in temperate grasslands were likely caused by differences in their utilization of water resources, which have different temporal and spatial distribution patterns. Leaf traits of shrubs and perennial grasses had the largest responses to variability of aridity through regulation of morphological, physiological and anatomical traits, which was followed by perennial forbs. Trees and annual grasses endured aridity only by adjusting leaf physiological processes. PMID:28106080

  20. Workshop on seedling physiology and growth problems in oak plantings (6th) (abstracts). Held in Tomahawk, Wisconsin on September 18-20, 1995. Forest Service general technical report

    SciTech Connect

    Teclaw, R.M.

    1996-07-01

    The sixth workshop on seedling physiology and growth problems in oak plantings was held at Treehaven, University of Wisconsin - Stevens Point Natural Resource and Education Center near Rhinelander, Wisconsin, on September 18-20, 1995. The 1995 workshop presentations addressed three general problem areas: (1) genetics and physiology, (2) nursery practices, and (3) silviculture and field practices of oak. A one day field tour followed the workshop where participants viewed three unique oak ecosystems. The first two stops were at northern hardwood sites, one a fertile mesic site - The Willow Springs Ecosystem Processes Study, the other a less fertile dry-mesic site - The Bird Lake Oak Regeneration Site. The tour concluded at a thinned red pine plantation where the association between pine and oak is being studied.

  1. Auxin: a major player in the shoot-to-root regulation of root Fe-stress physiological responses to Fe deficiency in cucumber plants.

    PubMed

    Bacaicoa, Eva; Mora, Verónica; Zamarreño, Angel María; Fuentes, Marta; Casanova, Esther; García-Mina, José María

    2011-05-01

    The aim of this study was to investigate the effects of IAA and ABA in the shoot-to-root regulation of the expression of the main Fe-stress physiological root responses in cucumber plants subjected to shoot Fe functional deficiency. Changes in the expression of the genes CsFRO1, CsIRT1, CsHA1 and CsHA2 (coding for Fe(III)-chelate reductase (FCR), the Fe(II) transporter and H+-ATPase, respectively) and in the enzyme activity of FCR and the acidification capacity were measured. We studied first the ability of exogenous applications of IAA and ABA to induce these Fe-stress root responses in plants grown in Fe-sufficient conditions. The results showed that IAA was able to activate these responses at the transcriptional and functional levels, whereas the results with ABA were less conclusive. Thereafter, we explored the role of IAA in plants with or without shoot Fe functional deficiency in the presence of two types of IAA inhibitors, affecting either IAA polar transport (TIBA) or IAA functionality (PCIB). The results showed that IAA is involved in the regulation at the transcriptional and functional levels of both Fe root acquisition (FCR, Fe(II) transport) and rhizosphere acidification (H+-ATPase), although through different, and probably complementary, mechanisms. These results suggest that IAA is involved in the shoot-to-root regulation of the expression of Fe-stress physiological root responses.

  2. Leaf δ15N as a physiological indicator of the responsiveness of N2-fixing alfalfa plants to elevated [CO2], temperature and low water availability

    PubMed Central

    Ariz, Idoia; Cruz, Cristina; Neves, Tomé; Irigoyen, Juan J.; Garcia-Olaverri, Carmen; Nogués, Salvador; Aparicio-Tejo, Pedro M.; Aranjuelo, Iker

    2015-01-01

    The natural 15N/14N isotope composition (δ15N) of a tissue is a consequence of its N source and N physiological mechanisms in response to the environment. It could potentially be used as a tracer of N metabolism in plants under changing environmental conditions, where primary N metabolism may be complex, and losses and gains of N fluctuate over time. In order to test the utility of δ15N as an indicator of plant N status in N2-fixing plants grown under various environmental conditions, alfalfa (Medicago sativa L.) plants were subjected to distinct conditions of [CO2] (400 vs. 700 μmol mol−1), temperature (ambient vs. ambient +4°C) and water availability (fully watered vs. water deficiency—WD). As expected, increased [CO2] and temperature stimulated photosynthetic rates and plant growth, whereas these parameters were negatively affected by WD. The determination of δ15N in leaves, stems, roots, and nodules showed that leaves were the most representative organs of the plant response to increased [CO2] and WD. Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates, but could also be related to a higher N demand in leaves, as suggested by the decreased leaf N and total soluble protein (TSP) contents detected at 700 μmol mol−1 [CO2] and WD conditions. In summary, leaf δ15N provides relevant information integrating parameters which condition plant responsiveness (e.g., photosynthesis, TSP, N demand, and water transpiration) to environmental conditions. PMID:26322051

  3. Leaf δ(15)N as a physiological indicator of the responsiveness of N2-fixing alfalfa plants to elevated [CO2], temperature and low water availability.

    PubMed

    Ariz, Idoia; Cruz, Cristina; Neves, Tomé; Irigoyen, Juan J; Garcia-Olaverri, Carmen; Nogués, Salvador; Aparicio-Tejo, Pedro M; Aranjuelo, Iker

    2015-01-01

    The natural (15)N/(14)N isotope composition (δ(15)N) of a tissue is a consequence of its N source and N physiological mechanisms in response to the environment. It could potentially be used as a tracer of N metabolism in plants under changing environmental conditions, where primary N metabolism may be complex, and losses and gains of N fluctuate over time. In order to test the utility of δ(15)N as an indicator of plant N status in N2-fixing plants grown under various environmental conditions, alfalfa (Medicago sativa L.) plants were subjected to distinct conditions of [CO2] (400 vs. 700 μmol mol(-1)), temperature (ambient vs. ambient +4°C) and water availability (fully watered vs. water deficiency-WD). As expected, increased [CO2] and temperature stimulated photosynthetic rates and plant growth, whereas these parameters were negatively affected by WD. The determination of δ(15)N in leaves, stems, roots, and nodules showed that leaves were the most representative organs of the plant response to increased [CO2] and WD. Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates, but could also be related to a higher N demand in leaves, as suggested by the decreased leaf N and total soluble protein (TSP) contents detected at 700 μmol mol(-1) [CO2] and WD conditions. In summary, leaf δ(15)N provides relevant information integrating parameters which condition plant responsiveness (e.g., photosynthesis, TSP, N demand, and water transpiration) to environmental conditions.

  4. Simple and robust determination of the activity signature of key carbohydrate metabolism enzymes for physiological phenotyping in model and crop plants.

    PubMed

    Jammer, Alexandra; Gasperl, Anna; Luschin-Ebengreuth, Nora; Heyneke, Elmien; Chu, Hyosub; Cantero-Navarro, Elena; Großkinsky, Dominik K; Albacete, Alfonso A; Stabentheiner, Edith; Franzaring, Jürgen; Fangmeier, Andreas; van der Graaff, Eric; Roitsch, Thomas

    2015-09-01

    The analysis of physiological parameters is important to understand the link between plant phenotypes and their genetic bases, and therefore is needed as an important element in the analysis of model and crop plants. The activities of enzymes involved in primary carbohydrate metabolism have been shown to be strongly associated with growth performance, crop yield, and quality, as well as stress responses. A simple, fast, and cost-effective method to determine activities for 13 key enzymes involved in carbohydrate metabolism has been established, mainly based on coupled spectrophotometric kinetic assays. The comparison of extraction buffers and requirement for dialysis of crude protein extracts resulted in a universal protein extraction protocol, suitable for the preparation of protein extracts from different organs of various species. Individual published kinetic activity assays were optimized and adapted for a semi-high-throughput 96-well assay format. These assays proved to be robust and are thus suitable for physiological phenotyping, enabling the characterization and diagnosis of the physiological state. The potential of the determination of distinct enzyme activity signatures as part of a physiological fingerprint was shown for various organs and tissues from three monocot and five dicot model and crop species, including two case studies with external stimuli. Differential and specific enzyme activity signatures are apparent during inflorescence development and upon in vitro cold treatment of young inflorescences in the monocot ryegrass, related to conditions for doubled haploid formation. Likewise, treatment of dicot spring oilseed rape with elevated CO2 concentration resulted in distinct patterns of enzyme activity responses in leaves.

  5. Autochthonous arbuscular mycorrhizal fungi and Bacillus thuringiensis from a degraded Mediterranean area can be used to improve physiological traits and performance of a plant of agronomic interest under drought conditions.

    PubMed

    Armada, Elisabeth; Azcón, Rosario; López-Castillo, Olga M; Calvo-Polanco, Mónica; Ruiz-Lozano, Juan Manuel

    2015-05-01

    Studies have shown that some microorganisms autochthonous from stressful environments are beneficial when used with autochthonous plants, but these microorganisms rarely have been tested with allochthonous plants of agronomic interest. This study investigates the effectiveness of drought-adapted autochthonous microorganisms [Bacillus thuringiensis (Bt) and a consortium of arbuscular mycorrhizal (AM) fungi] from a degraded Mediterranean area to improve plant growth and physiology in Zea mays under drought stress. Maize plants were inoculated or not with B. thuringiensis, a consortium of AM fungi or a combination of both microorganisms. Plants were cultivated under well-watered conditions or subjected to drought stress. Several physiological parameters were measured, including among others, plant growth, photosynthetic efficiency, nutrients content, oxidative damage to lipids, accumulation of proline and antioxidant compounds, root hydraulic conductivity and the expression of plant aquaporin genes. Under drought conditions, the inoculation of Bt increased significantly the accumulation of nutrients. The combined inoculation of both microorganisms decreased the oxidative damage to lipids and accumulation of proline induced by drought. Several maize aquaporins able to transport water, CO2 and other compounds were regulated by the microbial inoculants. The impact of these microorganisms on plant drought tolerance was complementary, since Bt increased mainly plant nutrition and AM fungi were more active improving stress tolerance/homeostatic mechanisms, including regulation of plant aquaporins with several putative physiological functions. Thus, the use of autochthonous beneficial microorganisms from a degraded Mediterranean area is useful to protect not only native plants against drought, but also an agronomically important plant such as maize.

  6. Science and Measurement Requirements for a Plant Physiology and Functional Types Mission: Measuring the Composition, Function and Health of Global Land and Coastal Ocean Ecosystems

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Rogez, Francois; Green, Rob; Ungar, Steve; Knox, Robert; Asner, Greg; Muller-Karger, Frank; Bissett, Paul; Chekalyuk, Alex; Dierssen, Heidi; Gamon, John; Hook, Simon; Meister, Gerhard; Middleton, Betsy; Ollinger, Scott; Roberts, Dar; Siegel, Dave; Townsend, Phil; Saatchi, Sassan; Unstin, Susan; Turner, Woody; Wickland, Diane; Bontempi, Paula; Emanuel, Bill

    2007-01-01

    This slide presentation reviews the proposed Plant Physiology and Functional Types (PPFT) Mission. The National Academy of Sciences Decadal Survey, placed a critical priority on a Mission to observe distribution and changes in ecosystem functions. The PPFT satellite mission provides the essential measurements needed to assess drivers of change in biodiversity and ecosystem services that affect human welfare. The presentation reviews the science questions that the mission will be designed to answer, the science rationale, the science measurements, the mission concept, the planned instrumentation, the calibration method, and key signal to noise ratios and uniformity requirements.

  7. Science and Measurement Requirements for a Plant Physiology and Functional Types Mission: Measuring the Composition, Function and Health of Global Land and Coastal Ocean Ecosystems

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Rogez, Francois; Green, Rob; Ungar, Steve; Knox, Robert; Asner, Greg; Muller-Karger, Frank; Bissett, Paul; Chekalyuk, Alex; Dierssen, Heidi; Gamon, John; Hook, Simon; Meister, Gerhard; Middleton, Betsy; Ollinger, Scott; Roberts, Dar; Siegel, Dave; Townsend, Phil; Saatchi, Sassan; Unstin, Susan; Turner, Woody; Wickland, Diane; Bontempi, Paula; Emanuel, Bill

    2007-01-01

    This slide presentation reviews the proposed Plant Physiology and Functional Types (PPFT) Mission. The National Academy of Sciences Decadal Survey, placed a critical priority on a Mission to observe distribution and changes in ecosystem functions. The PPFT satellite mission provides the essential measurements needed to assess drivers of change in biodiversity and ecosystem services that affect human welfare. The presentation reviews the science questions that the mission will be designed to answer, the science rationale, the science measurements, the mission concept, the planned instrumentation, the calibration method, and key signal to noise ratios and uniformity requirements.

  8. Evidence of translocation and physiological impacts of foliar applied CeO2 nanoparticles on cucumber (Cucumis sativus) plants.

    PubMed

    Hong, Jie; Peralta-Videa, Jose R; Rico, Cyren; Sahi, Shivendra; Viveros, Marian N; Bartonjo, Jane; Zhao, Lijuan; Gardea-Torresdey, Jorge L

    2014-04-15

    Currently, most of the nanotoxicity studies in plants involve exposure to the nanoparticles (NPs) through the roots. However, plants interact with atmospheric NPs through the leaves, and our knowledge on their response to this contact is limited. In this study, hydroponically grown cucumber (Cucumis sativus) plants were aerially treated either with nano ceria powder (nCeO2) at 0.98 and 2.94 g/m(3) or suspensions at 20, 40, 80, 160, and 320 mg/L. Fifteen days after treatment, plants were analyzed for Ce uptake by using ICP-OES and TEM. In addition, the activity of three stress enzymes was measured. The ICP-OES results showed Ce in all tissues of the CeO2 NP treated plants, suggesting uptake through the leaves and translocation to the other plant parts. The TEM results showed the presence of Ce in roots, which corroborates the ICP-OES results. The biochemical assays showed that catalase activity increased in roots and ascorbate peroxidase activity decreased in leaves. Our findings show that atmospheric NPs can be taken up and distributed within plant tissues, which could represent a threat for environmental and human health.

  9. The combined effect of salinity and heat reveals a specific physiological, biochemical and molecular response in tomato plants.

    PubMed

    Rivero, Rosa M; Mestre, Teresa C; Mittler, Ron; Rubio, Francisco; Garcia-Sanchez, Francisco; Martinez, Vicente

    2014-05-01

    Many studies have described the response mechanisms of plants to salinity and heat applied individually; however, under field conditions some abiotic stresses often occur simultaneously. Recent studies revealed that the response of plants to a combination of two different stresses is specific and cannot be deduced from the stresses applied individually. Here, we report on the response of tomato plants to a combination of heat and salt stress. Interestingly, and in contrast to the expected negative effect of the stress combination on plant growth, our results show that the combination of heat and salinity provides a significant level of protection to tomato plants from the effects of salinity. We observed a specific response of plants to the stress combination that included accumulation of glycine betaine and trehalose. The accumulation of these compounds under the stress combination was linked to the maintenance of a high K(+) concentration and thus a lower Na(+) /K(+) ratio, with a better performance of the cell water status and photosynthesis as compared with salinity alone. Our findings unravel new and unexpected aspects of the response of plants to stress combination and provide a proposed list of enzymatic targets for improving crop tolerance to the abiotic field environment.

  10. Nitrogen level and physiological basis of yield of mungbean at varying plant population in High Ganges River Flood Plain soil of Bangladesh.

    PubMed

    Mian, M A K; Hossain, J

    2014-07-01

    A field experiment was conducted at the Regional Agricultural Research Station of Bangladesh Agricultural Research Institute, Jessore during early kharif season of 2009 and 2010 to observe the effect of nitrogen on the physiological basis of yield of mungbean at varying plant population. In the experiment, four nitrogen levels (N0, N40, N60 and N80 kg ha(-1)) were assigned in the main plots and three plant population (P30, P35 and P40 m(-2)) in the sub plots. The results revealed that mungbean showed better growth in N60 and N80 kg ha(-1) representing higher values of CGR, TDM, LAI and plant height while N40 exhibited intermediate growth. Again, growth of mungbean was better in higher plant population (35-40 m(-2)) representing higher values of growth parameters. Seed yield of mungbean was obtained the highest (1908 kg ha(-1)) associated with the highest No. of pods plant(-1) (29.98), seeds pod(-1) (10.41) and 1000-seed weight (37.70 g) in N40 kg ha(-1). Further, seed yield of mungbean was the highest (1919 kg ha(-1)) in plant population of 40 m(-2). In interaction, seed yield was the highest (1963 kg ha(-1)) in N40 kg ha(-1) with plant population of 40 m(-2). The effect of applied nitrogen on the seed yield of mungbean can be explained 78% (R2 = 0.78) by this function (Y = 1540.70+16.069x-0.173x2). The optimum nitrogen level was 46 kg ha(-1) by using the developed functional model and then the predicted seed yield of mungbean would be 1944 kg ha(-1).

  11. Analytical traceability of melon (Cucumis melo var reticulatus): proximate composition, bioactive compounds, and antioxidant capacity in relation to cultivar, plant physiology state, and seasonal variability.

    PubMed

    Maietti, Annalisa; Tedeschi, Paola; Stagno, Caterina; Bordiga, Matteo; Travaglia, Fabiano; Locatelli, Monica; Arlorio, Marco; Brandolini, Vincenzo

    2012-06-01

    Two morphologically different cultivars of Italian melons (Baggio and Giusto) were characterized considering samples harvested in different times, at the beginning (BPP) and at the end of the physiological plant production period (EPP). Proximate composition, protein, minerals, pH, phenolic content, antioxidant capacity, ascorbic acid, carotenoids, condensed tannins, and flavonoids were measured, showing a significant decrease in EPP samples (phenolics, antioxidant capacity, condensed tannins, and flavonoids); ascorbic acid decreased in Giusto cv, carotenoids in Baggio cv. Mineral content increased in either the cultivars (EPP samples). Year-to-year difference was significantly highlighted; the plant growing cycle significantly affected the chemotype. Despite these effects, the Principal Component Analysis (PCA) permitted the discrimination of Baggio from Giusto cv, and the discrimination of BPP from EPP samples as well.

  12. Reproduction, physiology and biochemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter summarizes fundamental knowledge and recent discoveries about the reproduction, physiology and biochemistry of plant-parasitic nematodes. Various types of reproduction are reviewed, including sexual reproduction and mitotic and meiotic parthenogenesis. Although much is known about the p...

  13. Physiological variation among native and exotic winter annual plants associated with microbiotic crusts in the Mojave Desert

    USGS Publications Warehouse

    DeFalco, L.A.; Detling, J.K.; Tracy, C.R.; Warren, S.D.

    2001-01-01

    Microbiotic crusts are important components of many aridland soils. Research on crusts typically focuses on the increase in soil fertility due to N-fixing micro-organisms, the stabilization of soils against water and wind erosion and the impact of disturbance on N-cycling. The effect of microbiotic crusts on the associated plant community has received little attention. We quantified the influence of crusts on the production, species diversity, nutrient content and water relations of winter annual plant species associated with microbiotic soil crusts in the northeast Mojave Desert. Shoot biomass of winter annuals was 37% greater and plant density was 77% greater on crusts than were biomass and density on soils lacking crust cover (=bare soils). This greater production of annuals on crusts was likely due to enhanced soil conditions including an almost two-fold increase in soil organic matter and inorganic N compared to bare soils. Crusted soils also had 53% greater volumetric water content than bare soils during November and December, the time when winter annuals become established. As plant development progressed into spring, however, soil water availability decreased: More negative plant xylem water potentials were associated with greater plant biomass on crusted soils. Plants associated with microbiotic soil crusts had lower concentrations of N in shoots (mg N g-1 dry mass). However, total shoot N (mg N m-2) was the same in plants growing on the different soil types when biomass production peaked in April. Shoots had similar patterns in their concentration and content of P. Species diversity of annuals was not statistically different between the two soil types. Yet, while native annuals comprised the greatest proportion of shoot biomass on bare soils, exotic forbs and grasses produced more biomass on crusts. Total shoot nutrient content (biomass x concentration) of the two exotic annual species examined was dramatically greater on crusts than bare soils; only one

  14. The effect of plant growth-promoting rhizobacteria on the growth, physiology, and Cd uptake of Arundo donax L.

    PubMed

    Sarathambal, Chinnathambi; Khankhane, Premraj Jagoji; Gharde, Yogita; Kumar, Bhumesh; Varun, Mayank; Arun, Sellappan

    2017-04-03

    In this study, plant growth-promoting potential isolates from rhizosphere of 10 weed species grown in heavy metal-contaminated areas were identified and their effect on growth, antioxidant enzymes, and cadmium (Cd) uptake in Arundo donax L. was explored. Plant growth-promoting traits of isolates were also analyzed. These isolates were found to produce siderophores and enzymes such as 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and aid in solubilization of mineral nutrients and modulate plant growth and development. Based on the presence of multiple plant growth-promoting traits, isolates were selected for molecular characterization and inoculation studies. Altogether, 58 isolates were obtained and 20% of them were able to tolerate Cd up to 400 ppm. The sequence analysis of the 16S rRNA genes indicates that the isolates belong to the phylum Firmicutes. Bacillus sp. along with mycorrhizae inoculation significantly improves the growth, the activity of antioxidants enzymes, and the Cd uptake in A. donax than Bacillus alone. Highly significant correlations were observed between Cd uptake, enzymatic activities, and plant growth characteristics at 1% level of significance. The synergistic interaction effect between these organisms helps to alleviate Cd effects on soil. Heavy metal-tolerant isolate along with arbuscular mycorrhizae (AM) could be used to improve the phytoremedial potential of plants.

  15. Phytoextraction of trace elements and physiological changes in Indian mustard plants (Brassica nigra L.) grown in post methanated distillery effluent (PMDE) irrigated soil.

    PubMed

    Bharagava, R N; Chandra, R; Rai, V

    2008-11-01

    The metal accumulation potential and its physiological effects in Indian mustard plants (Brassica nigra L.) grown in soil irrigated with post methanated distillery effluent (25%, 50%, 75%, 100%, v/v) were studied after 30, 60 and 90 days after sowing. An increase in the chlorophyll and protein contents was recorded at the lower concentrations of post methanated distillery effluent (PMDE) at initial exposure periods followed by a decrease at higher concentrations of PMDE compared to their respective controls. An enhanced lipid peroxidation in tested plants was observed, which was evidenced by the increased malondialdehyde content in shoot, leaves and seeds at all the concentrations of PMDE and exposure periods compared to their respective controls. This study revealed that Indian mustard plants (B. nigra L.) are well adopted to tolerate and accumulate high quantities of trace elements due to increased level of antioxidants (cysteine and ascorbic acid) in root, shoot and leaves of the treated plants at all the concentrations and exposure periods except at 90 days, whereas a decrease was observed at 100% PMDE as compared to their respective controls.

  16. Capacity of the aquatic fern (Salvinia minima Baker) to accumulate high concentrations of nickel in its tissues, and its effect on plant physiological processes.

    PubMed

    Fuentes, Ignacio I; Espadas-Gil, Francisco; Talavera-May, Carlos; Fuentes, Gabriela; Santamaría, Jorge M

    2014-10-01

    An experiment was designed to assess the capacity of Salvinia minima Baker to uptake and accumulate nickel in its tissues and to evaluate whether or not this uptake can affect its physiology. Our results suggest that S. minima plants are able to take up high amounts of nickel in its tissues, particularly in roots. In fact, our results support the idea that S. minima might be considered a hyper-accumulator of nickel, as it is able to accumulate 16.3 mg g(-1) (whole plant DW basis). Our results also showed a two-steps uptake pattern of nickel, with a fast uptake of nickel at the first 6 to 12h of being expose to the metal, followed by a slow take up phase until the end of the experiment at 144 h. S. minima thus, may be considered as a fern useful in the phytoremediation of residual water bodies contaminated with this metal. Also from our results, S. minima can tolerate fair concentrations of the metal; however, at concentrations higher than 80 μM Ni (1.5 mg g(-1) internal nickel concentration), its physiological performance can be affected. For instance, the integrity of cell membranes was affected as the metal concentration and exposure time increased. The accumulation of high concentrations of internal nickel did also affect photosynthesis, the efficiency of PSII, and the concentration of photosynthetic pigments, although at a lower extent.

  17. Plant resistance to aphid feeding: behavioral, physiological, genetic and molecular cues regulate aphid host selection and feeding.

    PubMed

    Smith, C Michael; Chuang, Wen-Po

    2014-04-01

    Aphids damage major world food and fiber crops through direct feeding and transmission of plant viruses. Fortunately, the development of many aphid-resistant crop plants has provided both ecological and economic benefits to food production. Plant characters governing aphid host selection often dictate eventual plant resistance or susceptibility to aphid herbivory, and these phenotypic characters have been successfully used to map aphid resistance genes. Aphid resistance is often inherited as a dominant trait, but is also polygenic and inherited as recessive or incompletely dominant traits. Most aphid-resistant cultivars exhibit constitutively expressed defenses, but some cultivars exhibit dramatic aphid-induced responses, resulting in the overexpression of large ensembles of putative aphid resistance genes. Two aphid resistance genes have been cloned. Mi-1.2, an NBS-LRR gene from wild tomato, confers resistance to potato aphid and three Meloidogyne root-knot nematode species, and Vat, an NBS-LRR gene from melon, controls resistance to the cotton/melon aphid and to some viruses. Virulence to aphid resistance genes of plants occurs in 17 aphid species--more than half of all arthropod biotypes demonstrating virulence. The continual appearance of aphid virulence underscores the need to identify new sources of resistance of diverse sequence and function in order to delay or prevent biotype development.

  18. Physiological and molecular aspects of degradation of plant polysaccharides by fungi: what have we learned from Aspergillus?

    PubMed

    Culleton, Helena; McKie, Vincent; de Vries, Ronald P

    2013-08-01

    Plant biomass is the most abundant and usable carbon source for many fungal species. Due to its diverse and complex structure, fungi need to produce a large range of enzymes to degrade these polysaccharides into monomeric components. The fine-tuned production of such diverse enzyme sets requires control through a set of transcriptional regulators. Aspergillus has a strong potential for degrading biomass, thus this genus has become the most widely studied group of filamentous fungi in this area. This review examines Aspergillus as a successful degrader of plant polysaccharides, and reviews its potential in many industries such as biofuel and as a production host of homologous and heterologous proteins.

  19. Low level of selenium increases the efficacy of 24-epibrassinolide through altered physiological and biochemical traits of Brassica juncea plants.

    PubMed

    Naz, Fatima Salva; Yusuf, Mohammad; Khan, Tanveer A; Fariduddin, Qazi; Ahmad, Aqil

    2015-10-15

    This study was conducted to provide an insight into the effect of Se (through soil) induced changes in Brassica juncea plants in the presence and absence of 24-epibrassinolide (EBL; foliar). The Se treatments showed dual response, 10 μM of Se significantly increased growth, water relations, photosynthetic attributes along with carbonic anhydrase activity whereas its higher concentrations proved inhibitory in concentration dependent manner. The follow-up application of EBL to the Se stressed plants improved growth, water relations, photosynthesis and simultaneously enhanced the various antioxidant enzymes viz. catalase, peroxidase and superoxide dismutase with the excess accumulation of proline. In addition to this, 10 μM Se increases the efficacy of 10(-8) M of EBL and both in combination showed maximum increase for the growth and photosynthetic traits of plants. On the other hand, the elevated level of antioxidant enzymes as well as proline could have conferred tolerance to the Se-stressed plants resulting in improved growth, water relations and photosynthesis.

  20. Physiological impacts of soil pollution and arsenic uptake in three plant species: Agrostis capillaris, Solanum nigrum and Vicia faba.

    PubMed

    Austruy, A; Wanat, N; Moussard, C; Vernay, P; Joussein, E; Ledoigt, G; Hitmi, A

    2013-04-01

    In order to revegetate an industrial soil polluted by trace metals and metalloids (As, Pb, Cu, Cd, Sb), the impact of pollution on three plant species, Solanum nigrum and Agrostis capillaris, both native species in an industrial site, and Vicia faba, a plant model species, is studied. Following the study of soil pollution from the industrial wasteland of Auzon, it appears that the As is the principal pollutant. Particular attention is given to this metalloid, both in its content and its speciation in the soil that the level of its accumulation in plants. In V. faba and A. capillaris, the trace metals and metalloids inhibit the biomass production and involve a lipid peroxidation in the leaves. Furthermore, these pollutants cause a photosynthesis perturbation by stomatal limitations and a dysfunction of photosystem II. Whatever the plant, the As content is less than 0.1 percent of dry matter, the majority of As absorbed is stored in the roots which play the role of trap organ. In parallel, the culture of S. nigrum decreases significantly the exchangeable and weakly adsorbed fraction of As in rhizospheric soil. This study has highlighted the ability of tolerance to trace metals of S. nigrum and to a lesser extent A. capillaris. Our data indicate that V. faba is not tolerant to soil pollution and is not a metallophyte species.

  1. Comparison of individual and combined effects of salinity and deficit irrigation on physiological, nutritional and ornamental aspects of tolerance in Callistemon laevis plants.

    PubMed

    Álvarez, Sara; Sánchez-Blanco, M Jesús

    2015-08-01

    The effect of water deficit, salinity and both applied simultaneously on several physiological and morphological parameters in the ornamental plant Callistemon laevis was studied to identify the tolerance mechanisms developed by this species to these sources of stress and to evaluate their adaptability to such conditions. C. laevis plants were grown in pots outdoors and subjected to four irrigation treatments lasting ten months: control (0.8 dS m(-1), 100% water holding capacity), water deficit (0.8 dS m(-1), 50% of the amount of water supplied in control), saline (4.0 dS m(-1), same amount of water supplied as control) and saline water deficit (4.0 dS m(-1), 50% of the water supplied in the control). Water and saline stress, when applied individually, led to a reduction of 12% and 39% of total biomass, respectively, while overall plant quality (leaf color and flowering) was unaffected. However, saline water deficit affected leaf color and flowering and induced an excessive decrease of growth (68%) due to leaf tissue dehydration and a high leaf Cl and Na concentration. Biomass partitioning depended not only on the amount of water applied, but also on the electrical conductivity of the water. Water stress induced active osmotic adjustment and decreased leaf tissue elasticity. Although both Na and Cl concentrations in the plant tissues increased with salinity, Cl entry through the roots was more restricted. In plants submitted to salinity individually, Na tended to remain in the roots and stems, and little reached the leaves. However, plants simultaneously submitted to water and saline stress were not able to retain this ion in the woody parts. The decrease in stomatal conductance and photosynthesis was more marked in the plants submitted to both stresses, the effect of which decreased photosynthesis, and this together with membrane damage delayed plant recovery. The results show that the combination of deficit irrigation and salinity in C. laevis is not recommended

  2. Measuring sap flow, and other plant physiological conditions across a soil salinity gradient in the lower Colorado River at Cibola National Wildlife Refuge: Vegetation and soil physiology linkages with microwave dielectric constant

    NASA Astrophysics Data System (ADS)

    McDonald, K. C.; Lasne, Y.; Schroeder, R.; Morino, K.; Hultine, K. R.; Nagler, P. L.

    2009-12-01

    We used ground measurements to examine stand structure and evapotranspiration of Tamarix in the Cibola National Wildlife Refuge (CNWR) on the Lower Colorado River. Three Tamarix study sites were established at different distances from the Colorado River on a river terrace in the CNWR. The sites were chosen from aerial photographs to represent typical dense stands of Tamarix within the CNWR. The sites were representative of differing saline environments, with each having ground water with distinct salt concentration levels. Wells were established at the site to establish depth to water and the salinity concentration within the ground water. We monitored xylem sap flow within each of the three stands. In addition we measured leaf area index to characterize canopy structure. We compared ET, foliage density, depth to water, and salinity among the Tamarix sites to examine stand-level variability driven by the variations in salinity. We supplemented these collections with measurements to characterize soil and vegetation microwave dielectric properties and their relationship to physiologic parameters. The dielectric properties of a material describe the interaction of an electric field with the material. Previous field experiments have demonstrated that varying degrees of correlation exist between vegetation dielectric properties and tree canopy water status. Temporal variation of the dielectric constant of woody plant tissue may result from changes in water status (e.g., water content) and chemical composition, albeit to varying degrees of sensitivity. The varying amount of ground water salinity at CNWR offers a unique opportunity to examine the relationship between vegetation and soil dielectric constant as related to vegetation ecophysiology. A field portable vector network analyzer is used to measure the microwave dielectric spectrum of the soil and vegetation Combined with measurements of vegetation xylem sap flux and soil chemistry, these measurements allow

  3. Genome-Guided Insights into the Plant Growth Promotion Capabilities of the Physiologically Versatile Bacillus aryabhattai Strain AB211.

    PubMed

    Bhattacharyya, Chandrima; Bakshi, Utpal; Mallick, Ivy; Mukherji, Shayantan; Bera, Biswajit; Ghosh, Abhrajyoti

    2017-01-01

    Bacillus aryabhattai AB211 is a plant growth promoting, Gram-positive firmicute, isolated from the rhizosphere of tea (Camellia sinensis), one of the oldest perennial crops and a major non-alcoholic beverage widely consumed all over the world. The whole genome of B. aryabhattai AB211 was sequenced, annotated and evaluated with special focus on genomic elements related to plant microbe interaction. It's genome sequence reveals the presence of a 5,403,026 bp chromosome. A total of 5226 putative protein-coding sequences, 16 rRNA, 120 tRNA, 8 ncRNAs, 58 non-protein coding genes, and 11 prophage regions were identified. Genome sequence comparisons between strain AB211 and other related environmental strains of B. aryabhattai, identified about 3558 genes conserved among all B. aryabhattai genomes analyzed. Most of the common genes involved in plant growth promotion activities were found to be present within core genes of all the genomes used for comparison, illustrating possible common plant growth promoting traits shared among all the strains of B. aryabhattai. Besides the core genes, some genes were exclusively identified in the genome of strain AB211. Functional annotation of the genes predicted in the strain AB211 revealed the presence of genes responsible for mineral phosphate solubilization, siderophores, acetoin, butanediol, exopolysaccharides, flagella biosynthesis, surface attachment/biofilm formation, and indole acetic acid production, most of which were experimentally verified in the present study. Genome analysis and experimental evidence suggested that AB211 has robust central carbohydrate metabolism implying that this bacterium can efficiently utilize the root exudates and other organic materials as an energy source. Genes for the production of peroxidases, catalases, and superoxide dismutases, that confer resistance to oxidative stresses in plants were identified in AB211 genome. Besides these, genes for heat shock tolerance, cold shock tolerance, glycine

  4. Genome-Guided Insights into the Plant Growth Promotion Capabilities of the Physiologically Versatile Bacillus aryabhattai Strain AB211

    PubMed Central

    Bhattacharyya, Chandrima; Bakshi, Utpal; Mallick, Ivy; Mukherji, Shayantan; Bera, Biswajit; Ghosh, Abhrajyoti

    2017-01-01

    Bacillus aryabhattai AB211 is a plant growth promoting, Gram-positive firmicute, isolated from the rhizosphere of tea (Camellia sinensis), one of the oldest perennial crops and a major non-alcoholic beverage widely consumed all over the world. The whole genome of B. aryabhattai AB211 was sequenced, annotated and evaluated with special focus on genomic elements related to plant microbe interaction. It’s genome sequence reveals the presence of a 5,403,026 bp chromosome. A total of 5226 putative protein-coding sequences, 16 rRNA, 120 tRNA, 8 ncRNAs, 58 non-protein coding genes, and 11 prophage regions were identified. Genome sequence comparisons between strain AB211 and other related environmental strains of B. aryabhattai, identified about 3558 genes conserved among all B. aryabhattai genomes analyzed. Most of the common genes involved in plant growth promotion activities were found to be present within core genes of all the genomes used for comparison, illustrating possible common plant growth promoting traits shared among all the strains of B. aryabhattai. Besides the core genes, some genes were exclusively identified in the genome of strain AB211. Functional annotation of the genes predicted in the strain AB211 revealed the presence of genes responsible for mineral phosphate solubilization, siderophores, acetoin, butanediol, exopolysaccharides, flagella biosynthesis, surface attachment/biofilm formation, and indole acetic acid production, most of which were experimentally verified in the present study. Genome analysis and experimental evidence suggested that AB211 has robust central carbohydrate metabolism implying that this bacterium can efficiently utilize the root exudates and other organic materials as an energy source. Genes for the production of peroxidases, catalases, and superoxide dismutases, that confer resistance to oxidative stresses in plants were identified in AB211 genome. Besides these, genes for heat shock tolerance, cold shock tolerance

  5. Research on gravitational physiology

    NASA Technical Reports Server (NTRS)

    Brown, A. H.; Dahl, A. O.

    1974-01-01

    The topic of gravitational plant physiology was studied through aspects of plant development (in ARABIDOPSIS) and of behavior (in HELIANTHUS) as these were affected by altered g experience. The effect of increased g levels on stem polarity (in COLEUS) was also examined.

  6. From systems biology to photosynthesis and whole-plant physiology: a conceptual model for integrating multi-scale networks.

    PubMed

    Weston, David J; Hanson, Paul J; Norby, Richard J; Tuskan, Gerald A; Wullschleger, Stan D

    2012-02-01

    Network analysis is now a common statistical tool for molecular biologists. Network algorithms are readily used to model gene, protein and metabolic correlations providing insight into pathways driving biological phenomenon. One output from such an analysis is a candidate gene list that can be responsible, in part, for the biological process of interest. The question remains, however, as to whether molecular network analysis can be used to inform process models at higher levels of biological organization. In our previous work, transcriptional networks derived from three plant species were constructed, interrogated for orthology and then correlated with photosynthetic inhibition at elevated temperature. One unique aspect of that study was the link from co-expression networks to net photosynthesis. In this addendum, we propose a conceptual model where traditional network analysis can be linked to whole-plant models thereby informing predictions on key processes such as photosynthesis, nutrient uptake and assimilation, and C partitioning.

  7. Growth and physiological responses of submerged plant Vallisneria natans to water column ammonia nitrogen and sediment copper

    PubMed Central

    Zhu, Zhengjie; Song, Siyuan; Li, Pengshan; Jeelani, Nasreen; Wang, Penghe; Yuan, Hezhong; Zhang, Jinghan; An, Shuqing

    2016-01-01

    Background. The decline of submerged plant populations due to high heavy metal (e.g., Cu) levels in sediments and ammonia nitrogen (ammonia-N) accumulation in the freshwater column has become a significant global problem. Previous studies have evaluated the effect of ammonia-N on submerged macrophytes, but few have focused on the influence of sediment Cu on submerged macrophytes and their combined effects. Methods. In this paper, we selected three levels of ammonia-N (0, 3, and 6 mg L−1) and sediment Cu (25.75 ± 6.02 as the control, 125.75 ± 6.02, and 225.75 ± 6.02 mg kg−1), to investigate the influence of sediment Cu and ammonia-N on submerged Vallisneria natans. We measured the relative growth rate (RGR), above- and below- ground biomass, chlorophyll, non-protein thiol (NP-SH), and free proline. Results and Discussion. The below-ground biomass of V. natans decreased with increasing Cu sediment levels, suggesting that excessive sediment Cu can result in significant damage to the root of V. natans. Similarly, the above-ground biomass significantly decreased with increasing ammonia-N concentrations, indicating that excessive water ammonia-N can cause significant toxicity to the leaf of V. natans. In addition, high ammonia-N levels place a greater stress on submerged plants than sediment Cu, which is indicated by the decline of RGR and chlorophyll, and the increase of (NP-SH) and free proline. Furthermore, high sediment Cu causes ammonia-N to impose greater injury on submerged plants, and higher sediment Cu levels (Cu ≥ 125.75 mg kg−1) led to the tolerant values of ammonia-N for V. natans decreasing from 6 to 3 mg L−1. This study suggests that high sediment Cu restricts the growth of plants and intensifies ammonia-N damage to V. natans. PMID:27123381

  8. Engineering Triterpene and Methylated Triterpene Production in Plants Provides Biochemical and Physiological Insights into Terpene Metabolism1[OPEN

    PubMed Central

    Jiang, Zuodong; Kempinski, Chase; Bush, Caroline J.; Nybo, S. Eric; Chappell, Joe

    2016-01-01

    Linear, branch-chained triterpenes, including squalene (C30), botryococcene (C30), and their methylated derivatives (C31–C37), generated by the green alga Botryococcus braunii race B have received significant attention because of their utility as chemical and biofuel feedstocks. However, the slow growth habit of B. braunii makes it impractical as a production system. In this study, we evaluated the potential of generating high levels of botryococcene in tobacco (Nicotiana tabacum) plants by diverting carbon flux from the cytosolic mevalonate pathway or the plastidic methylerythritol phosphate pathway by the targeted overexpression of an avian farnesyl diphosphate synthase along with two versions of botryococcene synthases. Up to 544 µg g−1 fresh weight of botryococcene was achieved when this metabolism was directed to the chloroplasts, which is approximately 90 times greater than that accumulating in plants engineered for cytosolic production. To test if methylated triterpenes could be produced in tobacco, we also engineered triterpene methyltransferases (TMTs) from B. braunii into wild-type plants and transgenic lines selected for high-level triterpene accumulation. Up to 91% of the total triterpene contents could be converted to methylated forms (C31 and C32) by cotargeting the TMTs and triterpene biosynthesis to the chloroplasts, whereas only 4% to 14% of total triterpenes were methylated when this metabolism was directed to the cytoplasm. When the TMTs were overexpressed in the cytoplasm of wild-type plants, up to 72% of the total squalene was methylated, and total triterpene (C30+C31+C32) content was elevated 7-fold. Altogether, these results point to innate mechanisms controlling metabolite fluxes, including a homeostatic role for squalene. PMID:26603654

  9. Growth and physiological responses of submerged plant Vallisneria natans to water column ammonia nitrogen and sediment copper.

    PubMed

    Zhu, Zhengjie; Song, Siyuan; Li, Pengshan; Jeelani, Nasreen; Wang, Penghe; Yuan, Hezhong; Zhang, Jinghan; An, Shuqing; Leng, Xin

    2016-01-01

    Background. The decline of submerged plant populations due to high heavy metal (e.g., Cu) levels in sediments and ammonia nitrogen (ammonia-N) accumulation in the freshwater column has become a significant global problem. Previous studies have evaluated the effect of ammonia-N on submerged macrophytes, but few have focused on the influence of sediment Cu on submerged macrophytes and their combined effects. Methods. In this paper, we selected three levels of ammonia-N (0, 3, and 6 mg L(-1)) and sediment Cu (25.75 ± 6.02 as the control, 125.75 ± 6.02, and 225.75 ± 6.02 mg kg(-1)), to investigate the influence of sediment Cu and ammonia-N on submerged Vallisneria natans. We measured the relative growth rate (RGR), above- and below- ground biomass, chlorophyll, non-protein thiol (NP-SH), and free proline. Results and Discussion. The below-ground biomass of V. natans decreased with increasing Cu sediment levels, suggesting that excessive sediment Cu can result in significant damage to the root of V. natans. Similarly, the above-ground biomass significantly decreased with increasing ammonia-N concentrations, indicating that excessive water ammonia-N can cause significant toxicity to the leaf of V. natans. In addition, high ammonia-N levels place a greater stress on submerged plants than sediment Cu, which is indicated by the decline of RGR and chlorophyll, and the increase of (NP-SH) and free proline. Furthermore, high sediment Cu causes ammonia-N to impose greater injury on submerged plants, and higher sediment Cu levels (Cu ≥ 125.75 mg kg(-1)) led to the tolerant values of ammonia-N for V. natans decreasing from 6 to 3 mg L(-1). This study suggests that high sediment Cu restricts the growth of plants and intensifies ammonia-N damage to V. natans.

  10. Morpho-physiological response of Populus alba to erythromycin: A timeline of the health status of the plant.

    PubMed

    Pierattini, Erika Carla; Francini, Alessandra; Raffaelli, Andrea; Sebastiani, Luca

    2016-11-01

    Populus alba Villafranca clone was chosen for a proof of concept study to determine the potential uptake and accumulation of antibiotics by trees. Plants were grown hydroponically and irrigated with a recirculating Hoagland's nutrient solution (control) and Hoagland's nutrient solution fortified with erythromycin at 0.01, 0.1 and 1mgL(-1). After 3 and 28days of treatment, poplar plants were separated into roots, stem, and leaves. Plants showed good health all over the period of treatment, and no differences in poplar growth for all the concentrations of erythromycin tested were observed. Quantification of erythromycin was performed using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS) in positive ion mode using multiple reaction ion monitoring. Erythromycin was detected in all organs analyzed. Roots showed an erythromycin concentration tenfold higher than leaves. The photochemical efficiency of photosystem II did not show a dose-dependant trend. From the quenching analysis of chlorophyll fluorescence, low nonphotochemical quenching (NPQ) and high photochemical quenching (qP) for the first week of erythromycin exposure was observed, depending on leaves position along the stem. Results suggest a short term adaptation of the photosynthetic apparatus of Populus alba in response to environmental realistic erythromycin concentrations.

  11. Aftereffect conditions of prolonged space flight on physiological and biochemical processes and plant resistance Lycopersicon esculentum Mill. to pathogens

    NASA Astrophysics Data System (ADS)

    Mishchenko, Lidiya

    2016-07-01

    Tomatoes (Lycopersicon esculentum Mill.) - one of the most popular vegetables in Ukraine, they are a valuable product of therapeutic and dietetic foods because they contain a significant amount of nutrients and essential to the human body minerals and vitamins, but by the content of carotenoids - lycopene and β-carotene - is a powerful antioxidant. Therefore, tomato plants can be used successfully to astronauts on long space flights. We aftereffect was studied factors of space flight on the variety of tomato seeds Mir-1, which lasted (6 years) were on an orbital space station "Mir". Then, also after long-term storage in 2011, seeds were sown in the laboratory and received seedlings grown in field conditions Kiev region. The resulting seeds of the tomato crop in 2011 ("Space" and still) we used in our subsequent field studies in Kyiv and Poltava regions. We have previously shown that the "space" seeds had shown in 2011-2012 increased resistance to viruses PVY and PVM natural infectious background. Therefore, it is necessary continue the investigation and started to observe in future years, including 2015 and to analyze the results obtained. Because plants grown constantly in the field natural infectious background, there was a high probability of their defeat pathogens of different nature, including viruses. The works of many authors proved reduce the concentration of carotene and lycopene in tomatoes with the defeat of viruses (Raithak, 2012). In addition, the control plants were observed symptoms of such that is a viral infection, namely in 2011 - leaves curl in 2012 - except leaves curl and even mosaics. The research results were confirmed in 2013, namely on the plants of "space" seed no symptoms of, and in control - detection of potato virus Y (method RT-PCR) and symptoms of leaf curl and mosaic. During the bearing samples were taken leaves of the options and experiment conducted determination of photosynthetic pigments. It should be emphasized that in plant

  12. Assessment of operators’ mental workload using physiological and subjective measures in cement, city traffic and power plant control centers

    PubMed Central

    Fallahi, Majid; Motamedzade, Majid; Heidarimoghadam, Rashid; Soltanian, Ali Reza; Miyake, Shinji

    2016-01-01

    Background: The present study aimed to evaluate the operators’ mental workload (MW) of cement, city traffic control and power plant control centers using subjective and objective measures during system vital parameters monitoring. Methods: This cross-sectional study was conducted from June 2014 to February 2015 at the cement, city traffic control and power plant control centers. Electrocardiography and electroencephalography data were recorded from forty males during performing their daily working in resting, low mental workload (LMW), high mental workload (HMW) and recovery conditions (each block 5 minutes). The NASA-Task Load Index (TLX) was used to evaluate the subjective workload of the operators. Results: The results showed that increasing MW had a significant effect on the operators subjective responses in two conditions ([1,53] = 216.303, P < 0.001, η2 = 0.803). Also,the Task-MW interaction effect on operators subjective responses was significant (F [3, 53] = 12.628,P < 0.001, η2 = 0.417). Analysis of repeated measures analysis of variance (ANOVA) indicated that increasing mental demands had a significant effect on heart rate, low frequency/high frequency ratio, theta and alpha band activity. Conclusion: The results suggested that when operators’ mental demands especially in traffic control and power plant tasks increased, their mental fatigue and stress level increased and their mental health deteriorated. Therefore, it may be necessary to implement an ergonomic program or administrative control to manage mental probably health in these control centers. Furthermore, by evaluating MW, the control center director can organize the human resources for each MW condition to sustain the appropriate performance as well as improve system functions. PMID:27386425

  13. Can Physiological Endpoints Improve the Sensitivity of Assays with Plants in the Risk Assessment of Contaminated Soils?

    PubMed Central

    Gavina, Ana; Antunes, Sara C.; Pinto, Glória; Claro, Maria Teresa; Santos, Conceição; Gonçalves, Fernando; Pereira, Ruth

    2013-01-01

    Site-specific risk assessment of contaminated areas indicates prior areas for intervention, and provides helpful information for risk managers. This study was conducted in the Ervedosa mine area (Bragança, Portugal), where both underground and open pit exploration of tin and arsenic minerals were performed for about one century (1857 – 1969). We aimed at obtaining ecotoxicological information with terrestrial and aquatic plant species to integrate in the risk assessment of this mine area. Further we also intended to evaluate if the assessment of other parameters, in standard assays with terrestrial plants, can improve the identification of phytotoxic soils. For this purpose, soil samples were collected on 16 sampling sites distributed along four transects, defined within the mine area, and in one reference site. General soil physical and chemical parameters, total and extractable metal contents were analyzed. Assays were performed for soil elutriates and for the whole soil matrix following standard guidelines for growth inhibition assay with Lemna minor and emergence and seedling growth assay with Zea mays. At the end of the Z. mays assay, relative water content, membrane permeability, leaf area, content of photosynthetic pigments (chlorophylls and carotenoids), malondialdehyde levels, proline content, and chlorophyll fluorescence (Fv/Fm and ΦPSII) parameters were evaluated. In general, the soils near the exploration area revealed high levels of Al, Mn, Fe and Cu. Almost all the soils from transepts C, D and F presented total concentrations of arsenic well above soils screening benchmark values available. Elutriates of several soils from sampling sites near the exploration and ore treatment areas were toxic to L. minor, suggesting that the retention function of these soils was seriously compromised. In Z. mays assay, plant performance parameters (other than those recommended by standard protocols), allowed the identification of more phytotoxic soils. The

  14. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation

    NASA Astrophysics Data System (ADS)

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice ( Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m-2 day-1) and elevated UV-B radiation (E, a 20 % higher dose of UV-B than the reference, 14.4 kJ m-2 day-1), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha-1), Si1 (sodium silicate, 100 kg SiO2 ha-1), Si2 (sodium silicate, 200 kg SiO2 ha-1), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha-1). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate ( Pn), intercellular carbon dioxide (CO2) concentration ( Ci), transpiration rate ( Tr), stomatal conductivity ( Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3 %, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9 %, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2 %, respectively, but decreased Tr by 1.9-10.8 %, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  15. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation.

    PubMed

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice (Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m(-2) day(-1)) and elevated UV-B radiation (E, a 20% higher dose of UV-B than the reference, 14.4 kJ m(-2) day(-1)), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha(-1)), Si1 (sodium silicate, 100 kg SiO2 ha(-1)), Si2 (sodium silicate, 200 kg SiO2 ha(-1)), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha(-1)). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate (Pn), intercellular carbon dioxide (CO2) concentration (Ci), transpiration rate (Tr), stomatal conductivity (Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3%, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9%, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2%, respectively, but decreased Tr by 1.9-10.8%, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  16. Spatial variation of eco-physiological parameters in the lichen Pseudevernia furfuracea transplanted in an area surrounding a cement plant (S Italy).

    PubMed

    Lucadamo, Lucio; Corapi, Anna; Loppi, Stefano; Paoli, Luca; Gallo, Luana

    2015-08-01

    Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months (November 2010-January 2011) at 61 monitoring sites around a cement plant near Castrovillari (Calabria, southern Italy). NH3, NO x and SO2 concentrations were monitored monthly in a subarea of 10 sites (SA10) where the cement plant was located. At the end of the exposure period, the integrity of cell membranes; membrane lipid peroxidation (thiobarbituric acid reactive substances, TBARS level); vitality (cell respiration); chlorophyll a; chlorophyll b; carotenoids; phaeophytization quotient; photosynthetic efficiency and thalli concentrations of Al, Ca, Mg, V and Fe were measured. NO x concentrations correlated with the site distance from the cement plant while NH3 concentrations correlated with lichen vitality within SA10. For the monitoring area as a whole, only Fe and Mg concentrations correlated with membrane lipid peroxidation, while TBARS levels showed a significant increase and chlorophyll a, chlorophyll b and carotenoids a significant decrease with respect to the lichen origin area. Multivariate analysis (detrended correspondence analysis, cluster analysis and multi-response permutation procedure) of the eco-physiological parameters × monitoring sites data set resulted in four clusters termed C1, C2, C3 and C4. The eco-physiological parameters were compared among the four clusters and lichen origin area by one-way ANOVA. An index of environmental favourableness (IEF) to lichens was calculated to evaluate the spatial recovery of impaired values of TBARS, chlorophyll a, chlorophyll b, xanthophylls + carotenoids and phaeophytization quotient. The results indicate that there is no clear spatial trend in mycobiont impairment even though the IEF values suggest a higher number of sites with low levels of membrane lipid peroxidation in the 2--3-km distance band from the cement plant (the outermost) than in the two other distance bands (0-1 and 1-2 km). The photobiont seems to be

  17. Transcriptomic and physiological responses to fishmeal substitution with plant proteins in formulated feed in farmed Atlantic salmon (Salmo salar)

    PubMed Central

    2012-01-01

    Background Aquaculture of piscivorous fish is in continual expansion resulting in a global requirement to reduce the dependence on wild caught fish for generation of fishmeal and fish oil. Plant proteins represent a suitable protein alternative to fish meal and are increasingly being used in fish feed. In this study, we examined the transcriptional response of Atlantic salmon (Salmo salar) to a high marine protein (MP) or low fishmeal, higher plant protein replacement diet (PP), formulated to the same nutritional specification within previously determined acceptable maximum levels of individual plant feed materials. Results After 77 days of feeding the fish in both groups doubled in weight, however neither growth performance, feed efficiency, condition factor nor organ indices were significantly different. Assessment of histopathological changes in the heart, intestine or liver did not reveal any negative effects of the PP diet. Transcriptomic analysis was performed in mid intestine, liver and skeletal muscle, using an Atlantic salmon oligonucleotide microarray (Salar_2, Agilent 4x44K). The dietary comparison revealed large alteration in gene expression in all the tissues studied between fish on the two diets. Gene ontology analysis showed, in the mid intestine of fish fed PP, higher expression of genes involved in enteritis, protein and energy metabolism, mitochondrial activity/kinases and transport, and a lower expression of genes involved in cell proliferation and apoptosis compared to fish fed MP. The liver of fish fed PP showed a lower expression of immune response genes but a higher expression of cell proliferation and apoptosis processes that may lead to cell reorganization in this tissue. The skeletal muscle of fish fed PP vs MP was characterized by a suppression of processes including immune response, energy and protein metabolism, cell proliferation and apoptosis which may reflect a more energy efficient tissue. Conclusions The PP diet resulted in

  18. Biogeochemistry and plant physiological traits interact to reinforce patterns of post-fire dominance in boreal forests

    NASA Astrophysics Data System (ADS)

    Shenoy, A.; Kielland, K.; Johnstone, J. F.

    2011-12-01

    Increases in the frequency, extent, and severity of fire in the North American boreal region are projected to continue under a warming climate and are likely to be associated with changes in future vegetation composition. In interior Alaska, fire severity is linked to the relative dominance of deciduous versus coniferous canopy species. Severely burned areas have high levels of deciduous recruitment and subsequent stand dominance, while lightly burned areas exhibit black spruce self-replacement. To elucidate potential mechanisms by which differential fire severity results in differential post-fire vegetation development, we examined changes in soil nitrogen (N) supply (NO3- and NH4+) and in situ 15N uptake by young aspen (Populus tremuloides) and black spruce (Picea mariana) trees growing in lightly and severely burned areas. We hypothesized that (a) soil nitrate supply would be higher in severely burned sites and (b) since conifers have been shown to have a reduced physiological capacity for NO3- uptake, aspen would display greater rates of NO3- uptake than spruce in severely burned sites. Our results suggested that the composition and magnitude of inorganic N supply 14 years after the fire was nearly identical in high-severity and low-severity sites, and nitrate represented nearly 50% of the supply. However, both aspen and spruce took up substantially more NH4+-N than NO3- -N regardless of fire severity. Surprisingly, spruce exhibited only a moderately lower rate of NO3- uptake (μg N/g root-1h-1) than aspen. At the stand level, aspen took up nearly an order-of-magnitude more N per hectare in severely burned sites compared to lightly burned sites, while spruce exhibited the opposite pattern of N uptake with respect to fire severity. Whereas ammonium appeared to be preferred by both species, nitrate represented a larger component of N uptake (based on the NO3-:NH4+ uptake ratio) in aspen (0.7) than in spruce (0.4). We suggest that these species

  19. Unity in diversity, a systems approach to regulating plant cell physiology by 2-oxoglutarate-dependent dioxygenases.

    PubMed

    Kundu, Siddhartha

    2015-01-01

    Could a disjoint group of enzymes synchronize their activities and execute a complex multi-step, measurable, and reproducible response? Here, I surmise that the alpha-ketoglutarate dependent superfamily of non-haem iron (II) dioxygenases could influence cell physiology as a cohesive unit, and that the broad spectra of substrates transformed is an absolute necessity to this portrayal. This eclectic group comprises members from all major taxa, and participates in pesticide breakdown, hypoxia signaling, and osmotic stress neutralization. The oxidative decarboxylation of 2-oxoglutarate to succinate is coupled with a concomitant substrate hydroxylation and, in most cases, is followed by an additional specialized conversion. The domain profile of a protein sequence was used as an index of miscellaneous reaction chemistry and interpreted alongside existent kinetic data in a linear model of integrated function. Statistical parameters were inferred by the creation of a novel, empirically motivated flat-file database of over 3800 sequences (DB2OG) with putative 2-oxoglutarate dependent activity. The collated information was categorized on the basis of existing annotation schema. The data suggests that 2OG-dependent enzymes incorporate several desirable features of a systems level player. DB2OG, is free, accessible without a login to all users, and available at the following URL (http://comp-biol.theacms.in/DB2OG.html).

  20. Physiological Strategies to Improve the Performance of Spring Maize (Zea mays L.) Planted under Early and Optimum Sowing Conditions.

    PubMed

    Bakhtavar, Muhammad Amir; Afzal, Irfan; Basra, Shahzad Maqsood Ahmed; Ahmad, Azraf-Ul-Haq; Noor, Mehmood Ali

    2015-01-01

    Low temperature at stand establishment and high temperature at reproductive stage are involved in reduction of grain yield of spring maize. A field study was therefore conducted to evaluate different physiological strategies for improving performance of spring maize under temperature extremes. Seed priming and foliar spray with 3% moringa leaf extract (MLE) and 100 mg L-1 kinetin solution alone or in all possible combinations with each other at three growth stages (knee height, tasseling and grain filling stage) and hydropriming was compared with control. Seed priming plus foliar spray of MLE and kinetin significantly improved stand establishment especially under early sown crop as indicated by reduced mean emergence time (MET), improved emergence index (EI) and final emergence percentage (FEP). Similarly increased chlorophyll contents, crop growth rate, leaf area index, photosynthetic rate, transpiration rate, relative water content and decreased membrane permeability were recorded in both early and optimum sowing conditions in MLE priming plus foliar spray treatment. All these improvements were harvested in the form of increased yield and harvest index compared with control treatment. Overall crop sown at optimum time performed best but exogenous application of MLE through seed priming and foliar spray maximally improved the performance of early sown maize crop which is attributed more likely due to improved stand establishment, chlorophyll and phenolic contents, increased leaf area duration and grain filling period. It can be concluded that seed priming with MLE along with its foliar spray could increase production of maize under temperature extremes.

  1. Unity in diversity, a systems approach to regulating plant cell physiology by 2-oxoglutarate-dependent dioxygenases

    PubMed Central

    Kundu, Siddhartha

    2015-01-01

    Could a disjoint group of enzymes synchronize their activities and execute a complex multi-step, measurable, and reproducible response? Here, I surmise that the alpha-ketoglutarate dependent superfamily of non-haem iron (II) dioxygenases could influence cell physiology as a cohesive unit, and that the broad spectra of substrates transformed is an absolute necessity to this portrayal. This eclectic group comprises members from all major taxa, and participates in pesticide breakdown, hypoxia signaling, and osmotic stress neutralization. The oxidative decarboxylation of 2-oxoglutarate to succinate is coupled with a concomitant substrate hydroxylation and, in most cases, is followed by an additional specialized conversion. The domain profile of a protein sequence was used as an index of miscellaneous reaction chemistry and interpreted alongside existent kinetic data in a linear model of integrated function. Statistical parameters were inferred by the creation of a novel, empirically motivated flat-file database of over 3800 sequences (DB2OG) with putative 2-oxoglutarate dependent activity. The collated information was categorized on the basis of existing annotation schema. The data suggests that 2OG-dependent enzymes incorporate several desirable features of a systems level player. DB2OG, is free, accessible without a login to all users, and available at the following URL (http://comp-biol.theacms.in/DB2OG.html). PMID:25814993

  2. Surface coating changes the physiological and biochemical impacts of nano-TiO2 in basil (Ocimum basilicum) plants.

    PubMed

    Tan, Wenjuan; Du, Wenchao; Barrios, Ana C; Armendariz, Raul; Zuverza-Mena, Nubia; Ji, Zhaoxia; Chang, Chong Hyun; Zink, Jeffrey I; Hernandez-Viezcas, Jose A; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2017-03-01

    Little is known about the effects of surface coating on the interaction of engineered nanoparticles (ENPs) with plants. In this study, basil (Ocimum basilicum) was cultivated for 65 days in soil amended with unmodified, hydrophobic (coated with aluminum oxide and dimethicone), and hydrophilic (coated with aluminum oxide and glycerol) titanium dioxide nanoparticles (nano-TiO2) at 125, 250, 500, and 750 mg nano-TiO2 kg(-1) soil. ICP-OES/MS, SPAD meter, and UV/Vis spectrometry were used to determine Ti and essential elements in tissues, relative chlorophyll content, carbohydrates, and antioxidant response, respectively. Compared with control, hydrophobic and hydrophilic nano-TiO2 significantly reduced seed germination by 41% and 59%, respectively, while unmodified and hydrophobic nano-TiO2 significantly decreased shoot biomass by 31% and 37%, respectively (p ≤ 0.05). Roots exposed to hydrophobic particles at 750 mg kg(-1) had 87% and 40% more Ti than the pristine and hydrophilic nano-TiO2; however, no differences were found in shoots. The three types of particles affected the homeostasis of essential elements: at 500 mg kg(-)(1), unmodified particles increased Cu (104%) and Fe (90%); hydrophilic increased Fe (90%); while hydrophobic increased Mn (339%) but reduced Ca (71%), Cu (58%), and P (40%). However, only hydrophobic particles significantly reduced root elongation by 53%. Unmodified, hydrophobic, and hydrophilic particles significantly reduced total sugar by 39%, 38%, and 66%, respectively, compared with control. Moreover, unmodified particles significantly decreased reducing sugar (34%), while hydrophobic particles significantly reduced starch (35%). Although the three particles affected basil plants, coated particles impacted the most its nutritional quality, since they altered more essential elements, starch, and reducing sugars.

  3. Physiology-based prognostic modeling of the influence of changes in precipitation on a keystone dryland plant species.

    PubMed

    Coe, Kirsten K; Sparks, Jed P

    2014-12-01

    Fluctuations in mean annual precipitation (MAP) will strongly influence the ecology of dryland ecosystems in the future, yet, because individual precipitation events drive growth and resource availability for many dryland organisms, changes in intra-annual precipitation may disproportionately influence future dryland processes. This work examines the hypothesis that intra-annual precipitation changes will drive dryland productivity to a greater extent than changes to MAP. To test this hypothesis, we created a physiology-based model to predict the effects of precipitation change on a widespread biocrust moss that regulates soil structure, water retention, and nutrient cycling in drylands. First, we used the model to examine moss productivity over the next 100 years driven by alterations in MAP by ± 10, 20 and 30%, and changes in intra-annual precipitation (event size and frequency). Productivity increased as a function of MAP, but differed among simulations where intra-annual precipitation was manipulated under constant MAP. Supporting our hypothesis, this demonstrates that, even if MAP does not change, changes in the features of individual precipitation events can strongly influence long-term performance. Second, we used the model to examine 100-year productivity based on projected dryland precipitation from published global and regional models. These simulations predicted 25-63% reductions in productivity and increased moss mortality rates, declines that will likely alter water and nutrient cycling in dryland ecosystems. Intra-annual precipitation in model-based simulations was a stronger predictor of productivity compared to MAP, further supporting our hypothesis, and illustrating that intra-annual precipitation patterns may dominate dryland responses to altered precipitation in a future climate.

  4. Effect of dietary phytase transgenic corn on physiological characteristics and the fate of recombinant plant DNA in laying hens.

    PubMed

    Gao, Chunqi; Ma, Qiugang; Zhao, Lihong; Zhang, Jianyun; Ji, Cheng

    2014-01-01

    The study aimed to evaluate the potential effects of feeding with phytase transgenic corn (PTC) on organ weight, serum biochemical parameters and nutrient digestibility, and to determine the fate of the transgenic DNA in laying hens. A total of 144 50-week-old laying hens were grouped randomly into 2 treatments, with 8 replicates per treatment and 9 hens per replicate. Each treatment group of hens was fed with diets containing 62.4% non-transgenic conventional corn (CC) or PTC for 16 weeks. The phytase activity for CC was 37 FTU/kg of DM, whereas the phytase activity for PTC was 8,980 FTU/kg of DM. We observed that feeding PTC to laying hens had no adverse effect on organ weight or serum biochemical parameters (p>0.05). A fragment of a poultry-specific ovalbumin gene (ov) was amplified from all tissues of hens showing that the DNA preparations were amenable to PCR amplification. Neither the corn-specific invertase gene (ivr) nor the transgenic phyA2 gene was detected in the breast muscle, leg muscle, ovary, oviduct and eggs. The digestibility data revealed no significant differences between the hens that received the CC- and PTC-based diets in the digestibility of DM, energy, nitrogen and calcium (p>0.05). Phosphorus digestibility of hens fed the PTC-based diet was greater than that of hens fed the CC-based diet (58.03% vs 47.42%, p<0.01). Based on these results, it was concluded that the PTC had no deleterious effects on the organ weight or serum biochemical parameters of the laying hens. No recombinant phyA2 gene was detected in muscle tissues and reproductive organs of laying hens. The novel plant phytase was efficacious in improving the phosphorus digestibility of laying hens.

  5. A reassessment of substrate specificity and activation of phytochelatin synthases from model plants by physiologically relevant metals.

    PubMed

    Loscos, Jorge; Naya, Loreto; Ramos, Javier; Clemente, Maria R; Matamoros, Manuel A; Becana, Manuel

    2006-04-01

    Phytochelatin synthases (PCS) catalyze phytochelatin (PC) synthesis from glutathione (GSH) in the presence of certain metals. The resulting PC-metal complexes are transported into the vacuole, avoiding toxic effects on metabolism. Legumes have the unique capacity to partially or completely replace GSH by homoglutathione (hGSH) and PCs by homophytochelatins (hPCs). However, the synthesis of hPCs has received little attention. A search for PCS genes in the model legume Lotus (Lotus japonicus) resulted in the isolation of a cDNA clone encoding a protein (LjPCS1) highly homologous to a previously reported homophytochelatin synthase (hPCS) of Glycine max (GmhPCS1). Recombinant LjPCS1 and Arabidopsis (Arabidopsis thaliana) PCS1 (AtPCS1) were affinity purified and their polyhistidine-tags removed. AtPCS1 catalyzed hPC synthesis from hGSH alone at even higher rates than did LjPCS1, indicating that GmhPCS1 is not a genuine hPCS and that a low ratio of hPC to PC synthesis is an inherent feature of PCS1 enzymes. For both enzymes, hGSH is a good acceptor, but a poor donor, of gamma-glutamylcysteine units. Purified AtPCS1 and LjPCS1 were activated (in decreasing order) by Cd2+, Zn2+, Cu2+, and Fe3+, but not by Co2+ or Ni2+, in the presence of 5 mm GSH and 50 microm metal ions. Activation of both enzymes by Fe3+ was proven by the complete inhibition of PC synthesis by the iron-specific chelator desferrioxamine. Plants of Arabidopsis and Lotus accumulated (h)PCs only in response to a large excess of Cu2+ and Zn2+, but to a much lower extent than did with Cd2+, indicating that (h)PC synthesis does not significantly contribute in vivo to copper, zinc, and iron detoxification.

  6. Effect of Dietary Phytase Transgenic Corn on Physiological Characteristics and the Fate of Recombinant Plant DNA in Laying Hens

    PubMed Central

    Gao, Chunqi; Ma, Qiugang; Zhao, Lihong; Zhang, Jianyun; Ji, Cheng

    2014-01-01

    The study aimed to evaluate the potential effects of feeding with phytase transgenic corn (PTC) on organ weight, serum biochemical parameters and nutrient digestibility, and to determine the fate of the transgenic DNA in laying hens. A total of 144 50-week-old laying hens were grouped randomly into 2 treatments, with 8 replicates per treatment and 9 hens per replicate. Each treatment group of hens was fed with diets containing 62.4% non-transgenic conventional corn (CC) or PTC for 16 weeks. The phytase activity for CC was 37 FTU/kg of DM, whereas the phytase activity for PTC was 8,980 FTU/kg of DM. We observed that feeding PTC to laying hens had no adverse effect on organ weight or serum biochemical parameters (p>0.05). A fragment of a poultry-specific ovalbumin gene (ov) was amplified from all tissues of hens showing that the DNA preparations were amenable to PCR amplification. Neither the corn-specific invertase gene (ivr) nor the transgenic phyA2 gene was detected in the breast muscle, leg muscle, ovary, oviduct and eggs. The digestibility data revealed no significant differences between the hens that received the CC- and PTC-based diets in the digestibility of DM, energy, nitrogen and calcium (p>0.05). Phosphorus digestibility of hens fed the PTC-based diet was greater than that of hens fed the CC-based diet (58.03% vs 47.42%, p<0.01). Based on these results, it was concluded that the PTC had no deleterious effects on the organ weight or serum biochemical parameters of the laying hens. No recombinant phyA2 gene was detected in muscle tissues and reproductive organs of laying hens. The novel plant phytase was efficacious in improving the phosphorus digestibility of laying hens. PMID:25049929

  7. Improved representation of plant functional types and physiology in the Joint UK Land Environment Simulator (JULES v4.2) using plant trait information

    NASA Astrophysics Data System (ADS)

    Harper, Anna B.; Cox, Peter M.; Friedlingstein, Pierre; Wiltshire, Andy J.; Jones, Chris D.; Sitch, Stephen; Mercado, Lina M.; Groenendijk, Margriet; Robertson, Eddy; Kattge, Jens; Bönisch, Gerhard; Atkin, Owen K.; Bahn, Michael; Cornelissen, Johannes; Niinemets, Ülo; Onipchenko, Vladimir; Peñuelas, Josep; Poorter, Lourens; Reich, Peter B.; Soudzilovskaia, Nadjeda A.; van Bodegom, Peter

    2016-07-01

    Dynamic global vegetation models are used to predict the response of vegetation to climate change. They are essential for planning ecosystem management, understanding carbon cycle-climate feedbacks, and evaluating the potential impacts of climate change on global ecosystems. JULES (the Joint UK Land Environment Simulator) represents terrestrial processes in the UK Hadley Centre family of models and in the first generation UK Earth System Model. Previously, JULES represented five plant functional types (PFTs): broadleaf trees, needle-leaf trees, C3 and C4 grasses, and shrubs. This study addresses three developments in JULES. First, trees and shrubs were split into deciduous and evergreen PFTs to better represent the range of leaf life spans and metabolic capacities that exists in nature. Second, we distinguished between temperate and tropical broadleaf evergreen trees. These first two changes result in a new set of nine PFTs: tropical and temperate broadleaf evergreen trees, broadleaf deciduous trees, needle-leaf evergreen and deciduous trees, C3 and C4 grasses, and evergreen and deciduous shrubs. Third, using data from the TRY database, we updated the relationship between leaf nitrogen and the maximum rate of carboxylation of Rubisco (Vcmax), and updated the leaf turnover and growth rates to include a trade-off between leaf life span and leaf mass per unit area.Overall, the simulation of gross and net primary productivity (GPP and NPP, respectively) is improved with the nine PFTs when compared to FLUXNET sites, a global GPP data set based on FLUXNET, and MODIS NPP. Compared to the standard five PFTs, the new nine PFTs simulate a higher GPP and NPP, with the exception of C3 grasses in cold environments and C4 grasses that were previously over-productive. On a biome scale, GPP is improved for all eight biomes evaluated and NPP is improved for most biomes - the exceptions being the tropical forests, savannahs, and extratropical mixed forests where simulated NPP is too

  8. Physiological Waterfalls

    ERIC Educational Resources Information Center

    Leith, David E.

    1976-01-01

    Provides background information, defining areas within organ systems where physiological waterfalls exist. Describes pressure-flow relationships of elastic tubes (blood vessels, airways, renal tubules, various ducts). (CS)

  9. Pavlov's physiology factory.

    PubMed

    Todes, D P

    1997-06-01

    The author examines the forces and relations of production in Pavlov's laboratory at the Imperial Institute of Experimental Medicine during the first phase of its operation (1891-1904). As in any production site, the forces of production included its physical plant and technologies, its workforce (with its skills), and management's ideas about what constituted good products and how best to produce them. In Pavlov's laboratory, these included a physical plant adapted for physiological surgery and "chronic experiments," dog-technologies and experimental practices created in accordance with Pavlov's Bernardian vision of physiology, and a workforce dominated by physicians untrained in physiology who were seeking quick doctoral degrees. The relations of production featured an authoritarian structure and cooperative ethos that allowed Pavlov to use coworkers as extensions of his sensory reach, while enabling him constantly to monitor the work process, to control the "interpretive moments" in experiments, to incorporate results into his developing ideas, and to convert them efficiently into marketable products.

  10. Physiological Networks: towards systems physiology

    NASA Astrophysics Data System (ADS)

    Bartsch, Ronny P.; Bashan, Amir; Kantelhardt, Jan W.; Havlin, Shlomo; Ivanov, Plamen Ch.

    2012-02-01

    The human organism is an integrated network where complex physiologic systems, each with its own regulatory mechanisms, continuously interact, and where failure of one system can trigger a breakdown of the entire network. Identifying and quantifying dynamical networks of diverse systems with different types of interactions is a challenge. Here, we develop a framework to probe interactions among diverse systems, and we identify a physiologic network. We find that each physiologic state is characterized by a specific network structure, demonstrating a robust interplay between network topology and function. Across physiologic states the network undergoes topological transitions associated with fast reorganization of physiologic interactions on time scales of a few minutes, indicating high network flexibility in response to perturbations. The proposed system-wide integrative approach may facilitate new dimensions to the field of systems physiology.

  11. Rowing Physiology.

    ERIC Educational Resources Information Center

    Spinks, W. L.

    This review of the literature discusses and examines the methods used in physiological assessment of rowers, results of such assessments, and future directions emanating from research in the physiology of rowing. The first section discusses the energy demands of rowing, including the contribution of the energy system, anaerobic metabolism, and the…

  12. A 7500-year record of plant physiology as palaeoenvironmental proxy from tree-ring δ13C and growth rates - the CARATE project

    NASA Astrophysics Data System (ADS)

    Arppe, L.; Helama, S.; Mielikäinen, K.; Oinonen, M.; Timonen, M.

    2012-12-01

    This contribution presents a recently launched 4-year research project, "CARATE", aiming to produce new climatic and plant physiological records at high temporal resolution by the synthesis of annually/decadally resolved tree-ring archives of growth-rates and cellulose δ13C values from high-latitude continental Europe. The project mainly relies on a supra-long pinewood chronology from Finnish Lapland covering the mid and late Holocene times continuously through the millennia since 5634 B.C. until the present-day (Eronen et al. 2002, Helama et al. 2008). The chronology provides a highly sensitive, absolutely dated proxy record of past environment and climate variability at highest possible resolution that can be calibrated directly with instrumental records of environmental variables. While growth rate records are invaluable tools for paleoclimate research at high frequencies, tree-ring δ13C compositions have the potential to portray the high-to-low-frequency climate signals per se, without complications from time-series analysis. By combining isotope and growth rate information, we aim to reconstruct regional high- and low-frequency climate variability over the past 7500 years with increased reliability, and explore the climate forcings behind the observed variations. The project was started by studying the strength of the common climatic signal both within- and between-sites, and possible associations to tree-physiological parameters. For this purpose, a set of 70 living pine trees (Pinus sylvestris) , growing in proximity of the subfossil pinewood collection sites in western and eastern Lapland, were cored for analysis of growth rates and δ13C values. α-cellulose was extracted from decadal samples corresponding to the time period 1970-2010 including both early- and latewood. The δ13C time series show a consistent response to regional environmental forcing over the entire study area, with no discernable differences between western and eastern Lapland. Within

  13. Exposure studies of core-shell Fe/Fe(3)O(4) and Cu/CuO NPs to lettuce (Lactuca sativa) plants: Are they a potential physiological and nutritional hazard?

    PubMed

    Trujillo-Reyes, J; Majumdar, S; Botez, C E; Peralta-Videa, J R; Gardea-Torresdey, J L

    2014-02-28

    Iron and copper nanomaterials are widely used in environmental remediation and agriculture. However, their effects on physiological parameters and nutritional quality of terrestrial plants such as lettuce (Lactuca sativa) are still unknown. In this research, 18-day-old hydroponically grown lettuce seedlings were treated for 15 days with core-shell nanoscale materials (Fe/Fe(3)O(4), Cu/CuO) at 10 and 20mg/L, and FeSO(4)·7H(2)O and CuSO(4)·5H(2)O at 10mg/L. At harvest, Fe, Cu, micro and macronutrients were determined by ICP-OES. Also, we evaluated chlorophyll content, plant growth, and catalase (CAT) and ascorbate peroxidase (APX) activities. Our results showed that iron ions/NPs did not affect the physiological parameters with respect to water control. Conversely, Cu ions/NPs reduced water content, root length, and dry biomass of the lettuce plants. ICP-OES results showed that nano-Cu/CuO treatments produced significant accumulation of Cu in roots compared to the CuSO(4)·5H(2)O treatment. In roots, all Cu treatments increased CAT activity but decreased APX activity. In addition, relative to the control, nano-Cu/CuO altered the nutritional quality of lettuce, since the treated plants had significantly more Cu, Al and S but less Mn, P, Ca, and Mg.

  14. Regulatory Physiology

    NASA Technical Reports Server (NTRS)

    Lane, Helen W.; Whitson, Peggy A.; Putcha, Lakshmi; Baker, Ellen; Smith, Scott M.; Stewart, Karen; Gretebeck, Randall; Nimmagudda, R. R.; Schoeller, Dale A.; Davis-Street, Janis

    1999-01-01

    As noted elsewhere in this report, a central goal of the Extended Duration Orbiter Medical Project (EDOMP) was to ensure that cardiovascular and muscle function were adequate to perform an emergency egress after 16 days of spaceflight. The goals of the Regulatory Physiology component of the EDOMP were to identify and subsequently ameliorate those biochemical and nutritional factors that deplete physiological reserves or increase risk for disease, and to facilitate the development of effective muscle, exercise, and cardiovascular countermeasures. The component investigations designed to meet these goals focused on biochemical and physiological aspects of nutrition and metabolism, the risk of renal (kidney) stone formation, gastrointestinal function, and sleep in space. Investigations involved both ground-based protocols to validate proposed methods and flight studies to test those methods. Two hardware tests were also completed.

  15. Reproductive physiology

    USGS Publications Warehouse

    Gee, G.F.; Russman, S.E.; Ellis, David H.; Gee, George F.; Mirande, Claire M.

    1996-01-01

    Conclusions: Although the general pattern of avian physiology applies to cranes, we have identified many physiological mechanisms (e.g., effects of disturbance) that need further study. Studies with cranes are expensive compared to those done with domestic fowl because of the crane's larger size, low reproductive rate, and delayed sexual maturity. To summarize, the crane reproductive system is composed of physiological and anatomical elements whose function is controlled by an integrated neural-endocrine system. Males generally produce semen at a younger age than when females lay eggs. Eggs are laid in clutches of two (1 to 3), and females will lay additional clutches if the preceding clutches are removed. Both sexes build nests and incubate the eggs. Molt begins during incubation and body molt may be completed annually in breeding pairs. However, remiges are replaced sequentially over 2 to 3 years, or abruptly every 2 to 3 years in other species. Most immature birds replace their juvenal remiges over a 2 to 3 year period. Stress interferes with reproduction in cranes by reducing egg production or terminating the reproductive effort. In other birds, stress elevates corticosterone levels and decreases LHRH release. We know little about the physiological response of cranes to stress.

  16. Seed isotopic analysis as a tool to understand ecological processes influencing plant development and physiology: the case study of Quercus rotundifolia Lam. in a desertification gradient in Mediterranean areas

    NASA Astrophysics Data System (ADS)

    Oliveira, Tatiana; Silva, Anabela; Rodrigues, Carla; Antunes Antunes, Cristina; Pinho, Pedro; Ramos, Alzira; João Pereira, Maria; Branquinho, Cristina; Máguas, Cristina

    2014-05-01

    Plant responses to climate change highly depend on the temporal variability in precipitation events and on plant specific strategies, such as drought tolerance and resilience. Within the different plant organs, seeds have become an important research tool in the past years to study plant development and nutrients allocation. Key features of seeds such as the tendency to accumulate and store nutrient compounds open many possibilities to explore isotope analysis (13C, 15N and 18O), with many outcomes in fields from ecology to food traceability. The application of light stable isotopes to plant materials have been used to study both physiological (i.e. photosynthesis and stomatal conductance), nutrients uptake and metabolism (origin of nitrogen and symbiotic associations) as well as many ecological processes, which will produce a distinctive isotope fingerprint on the plant tissues. Thus, the isotopic composition of certain bio and geo-elements of seeds, yielding relevant information on plant ecophysiology, are able to relate the plant functioning with local climatic conditions (e.g., temperature and precipitation). The application of isotope analysis in this way can be used as a proxy to understand complex environmental degradation processes such as land degradation in drylands resulting from various factors including climatic variations and human activities. In this study acorns of Quercus ilex plants were sampled during 2012-2013 in a region of southern Portugal, according to (i) soil land-use; (ii) aridity and desertification indexes. The approach developed combined plant seed analysis (seed morphology and compounds quantification) with isotope ratio mass spectrometry (δ13C, δ15N and δ18O) as a "tool" to study changes in plant ecophysiology over time and space. Seeds allow studies at specific temporal scale (development period) which varies according to its biology and depends on the climatic conditions where the plant is grown (i.e, seed's biomass integrate

  17. Elevated CO2, warmer temperatures and soil water deficit affect plant growth, physiology and water use of cotton (Gossypium hirsutum L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes in temperature, atmospheric [CO2] and precipitation under the scenarios of projected climate change present a challenge to crop production, and may have significant impacts on the physiology, growth and yield of cotton (Gossypium hirsutum L.). A glasshouse experiment explored the early growt...

  18. A Plant Bioindicator System for Estimating Pollution Abatement - Elucidation of the Ultrastructural, Physiological, and Biochemical Basis of Sensitive and Tolerance to NO2, SO2, and O3.

    DTIC Science & Technology

    1982-01-15

    Physiology 100% SMY Thesis Title: Epicuticular wax and stomata characterization of two Pinus strobus L. clones differing in sensit ity to ozone. pp. 79 L...measurement in providing reliable indexing parameter for white pine pollu- tion sensitivity prediction. EPICUTICULAR WAX AND STOMATA CHARACTERIZATION

  19. Influence of thiourea application on some physiological and molecular criteria of sunflower (Helianthus annuus L.) plants under conditions of heat stress.

    PubMed

    Akladious, Samia Ageeb

    2014-05-01

    High temperature is a major factor limiting the growth of plant species during summer. Understanding the mechanisms of plant tolerance to high temperature would help in developing effective management practices and heat-tolerant cultivars through breeding or biotechnology. The present investigation was carried out to study the role of thiourea in enhancing the tolerance of sunflower plants to heat stress. Sunflower plants were subjected to temperature stress by exposing plants to 35 or 45 °C for 12 h. Two levels of thiourea (10 and 20 mM) were applied before sowing (seed treatment). The results indicated that the plants exposed to temperature stress exhibited a significant decline in growth parameters, chlorophylls, relative leaf water content, oil content, leaf nutrient status, and nitrate reductase activity. Treatment with thiourea, especially when applied at 10 mM, improved the above parameters and induced non-enzymatic and enzymatic antioxidants responsible for antioxidation. SDS-PAGE of protein revealed that high-temperature treatments alone or in combination with thiourea were associated with the disappearance of some bands or the appearance of unique ones. The result of RAPD analysis using five primers showed variable qualitative and quantitative changes. These findings confirm the effectiveness of applying thiourea on alleviating heat injuries in sunflower plants.

  20. Physiological responses induced in tomato plants by a two-component nanostructural system composed of carbon nanotubes conjugated with quantum dots and its in vivo multimodal detection.

    PubMed

    Alimohammadi, Mohammad; Xu, Yang; Wang, Daoyuan; Biris, Alexandru S; Khodakovskaya, Mariya V

    2011-07-22

    Plant seedlings were exposed to single-walled carbon nanotube-quantum dot conjugates (SWCNT-QD) mixed in the growth medium in order to understand the interactions between these multicomponent nanosystems and plants. A combination of fluorescent and Raman-scattering 2D mapping analysis was used to clearly monitor the presence of the SWCNT-QD conjugates in various parts of the tomato seedlings. We found that the addition of QDs to SWCNTs dramatically changed the biological viability of the tomato plants by significantly accelerating leaf senescence and inhibiting root formation. Although the exposure of SWCNTs only to the plants induced positive effects, the chlorophyll content decreased by 1.5-fold in leaves, and the total weight of the root system decreased four times for the tomato plants exposed to SWCNT-QDs (50 µg ml(-1)) compared to plants grown on regular medium as controls. Our results clearly indicate that the exposure of plants to multicomponent nanomaterials is highly influenced by the presence and bioactivity of each component, individually. Such studies could be the foundation for understanding how complex nanosized systems affect the activity of various biological systems with a major impact on ecotoxicology.

  1. Physiological responses induced in tomato plants by a two-component nanostructural system composed of carbon nanotubes conjugated with quantum dots and its in vivo multimodal detection

    NASA Astrophysics Data System (ADS)

    Alimohammadi, Mohammad; Xu, Yang; Wang, Daoyuan; Biris, Alexandru S.; Khodakovskaya, Mariya V.

    2011-07-01

    Plant seedlings were exposed to single-walled carbon nanotube-quantum dot conjugates (SWCNT-QD) mixed in the growth medium in order to understand the interactions between these multicomponent nanosystems and plants. A combination of fluorescent and Raman-scattering 2D mapping analysis was used to clearly monitor the presence of the SWCNT-QD conjugates in various parts of the tomato seedlings. We found that the addition of QDs to SWCNTs dramatically changed the biological viability of the tomato plants by significantly accelerating leaf senescence and inhibiting root formation. Although the exposure of SWCNTs only to the plants induced positive effects, the chlorophyll content decreased by 1.5-fold in leaves, and the total weight of the root system decreased four times for the tomato plants exposed to SWCNT-QDs (50 µg ml - 1) compared to plants grown on regular medium as controls. Our results clearly indicate that the exposure of plants to multicomponent nanomaterials is highly influenced by the presence and bioactivity of each component, individually. Such studies could be the foundation for understanding how complex nanosized systems affect the activity of various biological systems with a major impact on ecotoxicology.

  2. Influence of salinity on the in vitro development of Glomus intraradices and on the in vivo physiological and molecular responses of mycorrhizal lettuce plants.

    PubMed

    Jahromi, Farzad; Aroca, Ricardo; Porcel, Rosa; Ruiz-Lozano, Juan Manuel

    2008-01-01

    Increased salinization of arable land is expected to have devastating global effects in the coming years. Arbuscular mycorrhizal fungi (AMF) have been shown to improve plant tolerance to abiotic environmental factors such as salinity, but they can be themselves negatively affected by salinity. In this study, the first in vitro experiment analyzed the effects of 0, 50, or 100 mM NaCl on the development and sporulation of Glomus intraradices. In the second experiment, the effects of mycorrhization on the expression of key plant genes expected to be affected by salinity was evaluated. Results showed that the assayed isolate G. intraradices DAOM 197198 can be regarded as a moderately salt-tolerant AMF because it did not significantly decrease hyphal development or formation of branching absorbing structures at 50 mM NaCl. Results also showed that plants colonized by G. intraradices grew more than nonmycorrhizal plants. This effect was concomitant with a higher relative water content in AM plants, lower proline content, and expression of Lsp5cs gene (mainly at 50 mM NaCl), lower expression of the stress marker gene Lslea gene, and lower content of abscisic acid in roots of mycorrhizal plants as compared to nonmycorrhizal plants, which suggest that the AM fungus decreased salt stress injury. In addition, under salinity, AM symbiosis enhanced the expression of LsPIP1. Such enhanced gene expression could contribute to regulating root water permeability to better tolerate the osmotic stress generated by salinity.

  3. Changes in growth, physiological parameters and the hormonal status of Myrtus communis L. plants irrigated with water with different chemical compositions.

    PubMed

    Acosta-Motos, José Ramón; Ortuño, María Fernanda; Álvarez, Sara; López-Climent, María Fernanda; Gómez-Cadenas, Aurelio; Sánchez-Blanco, María Jesús

    2016-02-01

    Myrtus communis, an important Mediterranean ornamental shrub, was used to study the effect of irrigation water with different chemical compositions in the plant response. A treatment with NaCl was used to establish the plant resistance to high salinity at long term. Plants were subjected to four irrigation treatments with drainage for three months: Control (0.8 dS m(-1)); two treatments using reclaimed water (RWs): RW1 (2.0 dS m(-1)) and RW2 (5.0 dS m(-1)); and NaCl (10.0 dS m(-1)). High levels of electric conductivity of RWs not affected plant growth, while NaCl decreased leaf dry weight. Coinciding with the accumulation of Na(+) and Cl(-) in the roots, soil water potential decreased, which hinders the mobilization of water to the leaves, decreasing leaf water potential. The osmotic adjustment in the NaCl treatment was due to Na(+) and Cl(-) ions, although the proline could contribute as an Osmo compatible solute, increasing the turgor plants. Also changes in cell walls rigidity minimize the negative effects on the water balance; however, a higher lipid peroxidation was observed in these plants. Stomatal closure was associated with a decrease in K(+) and an increase in abscisic acid. NaCl produced an increase in salicylic acid and did not affect jasmonic acid contents at the end of the experiment. Similar behavior in soil and leaf water potentials, although less pronounced than in NaCl, was shown in RW2 plants. The abscisic acid increased in the RW2 with respect to the control and a decrease in stomatal conductance was observed at the end of the experiment. Plants irrigated with RW1 behaved similarly to the control.

  4. Weaving Together Space Biology and the Human Research Program: Selecting Crops and Manipulating Plant Physiology to Produce High Quality Food for ISS Astronauts

    NASA Technical Reports Server (NTRS)

    Massa, Gioia; Hummerick, Mary; Douglas, Grace; Wheeler, Raymond

    2015-01-01

    Researchers from the Human Research Program (HRP) have teamed up with plant biologists at KSC to explore the potential for plant growth and food production on the international space station (ISS) and future exploration missions. KSC Space Biology (SB) brings a history of plant and plant-microbial interaction research for station and for future bioregenerative life support systems. JSC HRP brings expertise in Advanced Food Technology (AFT), Advanced Environmental Health (AEH), and Behavioral Health and Performance (BHP). The Veggie plant growth hardware on the ISS is the platform that first drove these interactions. As we prepared for the VEG-01 validation test of Veggie, we engaged with BHP to explore questions that could be asked of the crew that would contribute both to plant and to behavioral health research. AFT, AEH and BHP stakeholders were engaged immediately after the return of the Veggie flight samples of space-grown lettuce, and this team worked with the JSC human medical offices to gain approvals for crew consumption of the lettuce on ISS. As we progressed with Veggie testing we began performing crop selection studies for Veggie that were initiated through AFT. These studies consisted of testing and down selecting leafy greens, dwarf tomatoes, and dwarf pepper crops based on characteristics of plant growth and nutritional levels evaluated at KSC, and organoleptic quality evaluated at JSCs Sensory Analysis lab. This work has led to a successful collaborative proposal to the International Life Sciences Research Announcement for a jointly funded HRP-SB investigation of the impacts of light quality and fertilizer on salad crop productivity, nutrition, and flavor in Veggie on the ISS. With this work, and potentially with other pending joint projects, we will continue the synergistic research that will advance the space biology knowledge base, help close gaps in the human research roadmap, and enable humans to venture out to Mars and beyond.

  5. Effects of elevated carbon dioxide and drought on the growth and physiology of clonal Sitka spruce plants (Picea sitchensis (Bong.) Carr.).

    PubMed

    Townend, J

    1993-12-01

    Two-year-old Sitka spruce (Picea sitchensis (Bong.) Carr.) plants from four clones were grown in naturally lit growth chambers for 6 months at either ambient (350 ppm) or ambient + 250 ppm (600 ppm) CO(2) concentration. Plants were grown in large boxes filled with peat, in a system that allowed the roots of individual plants to be harvested easily at the end of the growing season. Half of the boxes were kept well watered and half were allowed to dry out slowly over the summer. Plants growing in elevated CO(2) showed a 6.9% increase in mean relative growth rate compared to controls in the drought treatment and a 9.8% increase compared to controls in the well-watered treatment, though there was considerable variation in response among the different clones and water treatments. Rates of net CO(2) assimilation were higher and stomatal conductances were lower in plants grown in elevated CO(2) than in ambient CO(2) in both the well-watered and drought treatments. Both of these factors contributed to the doubling of instantaneous water use efficiency. The partitioning of biomass to roots was unaffected by elevated CO(2), but the ratio of needle mass/stems + branches mass decreased. Together with reduced stomatal conductance, this probably caused the observed increases in xylem pressure potentials with elevated CO(2).

  6. Biodiversity, bioaccumulation and physiological changes in lichens growing in the vicinity of coal-based thermal power plant of Raebareli district, north India.

    PubMed

    Bajpai, Rajesh; Upreti, Dalip K; Nayaka, S; Kumari, B

    2010-02-15

    The lichen diversity assessment carried out around a coal-based thermal power plant indicated the increase in lichen abundance with the increase in distance from power plant in general. The photosynthetic pigments, protein and heavy metals were estimated in Pyxine cocoes (Sw.) Nyl., a common lichen growing around thermal power plant for further inference. Distributions of heavy metals from power plant showed positive correlation with distance for all directions, however western direction has received better dispersion as indicated by the concentration coefficient-R(2). Least significant difference analysis showed that speed of wind and its direction plays a major role in dispersion of heavy metals. Accumulation of Al, Cr, Fe, Pb and Zn in the thallus suppressed the concentrations of pigments like chlorophyll a, chlorophyll b and total chlorophyll, however, enhanced the level of protein. Further, the concentrations of chlorophyll contents in P. cocoes increased with the decreasing the distance from the power plant, while protein, carotenoid and phaeophytisation exhibited significant decrease.

  7. Physiological Acoustics

    NASA Astrophysics Data System (ADS)

    Young, Eric D.

    The analysis of physiological sound in the peripheral auditory system solves three important problems. First, sound energy impinging on the head must be captured and presented to the transduction apparatus in the ear as a suitable mechanical signal; second, this mechanical signal needs to be transduced into a neural representation that can be used by the brain; third, the resulting neural representation needs to be analyzed by central neurons to extract information useful to the animal. This chapter provides an overview of some aspects of the first two of these processes. The description is entirely focused on the mammalian auditory system, primarily on human hearing and on the hearing of a few commonly used laboratory animals (mainly rodents and carnivores). Useful summaries of non-mammalian hearing are available [1]. Because of the large size of the literature, review papers are referenced wherever possible.

  8. Molecular and physiological changes in response to salt stress in Citrus macrophylla W plants overexpressing Arabidopsis CBF3/DREB1A.

    PubMed

    Alvarez-Gerding, Ximena; Espinoza, Carmen; Inostroza-Blancheteau, Claudio; Arce-Johnson, Patricio

    2015-07-01

    Plant stress induced by high salinity has leading to an important reduction in crop yields. Due to their tropical origin, citrus fruits are highly sensitive to salts. Rootstocks are the root system of fruit trees, regulating ion uptake and transport to the canopy. Therefore, increasing their salt tolerance could improve the salt tolerance of the fruit tree. For this, we genetically-transformed an important rootstock for lemon, Citrus macrophylla W, to constitutively express the CBF3/DREB1A gene from Arabidopsis, a well-studied salinity tolerance transcription factor. Transgenic lines showed normal size, with no dwarfism. Under salt stress, some transgenic lines showed greater growth, similar accumulation of chloride and sodium in the leaves and better stomatal conductance, in comparison to wild-type plants. Quantitative real-time analyses showed a similar expression of several CBF3/DREB1A target genes, such as COR15A, LEA 4/5, INV, SIP1, P5CS, GOLS, ADC2 and LKR/SDH, in transgenic lines and wild type plants, with the exception of INV that shows increased expression in line 4C15. Under salt stress, all measured transcript increased in both wild type and transgenics lines, with the exception of INV. Altogether, these results suggest a higher salt tolerance of transgenic C. macrophylla plants induced by the overexpression of AtCBF3/DREB1A.

  9. Growth and physiology of woody plants in response to elevated CO{sub 2} and defoliation in an open-top field study

    SciTech Connect

    Volin, J.C.; Kruger, E.L.; Lindroth, R.L.

    1995-06-01

    Seedlings of sugar maple (Acer saccharum) and trembling aspen (Populus tremuloides) were exposed for an entire growing season to ambient (-357 {mu}mol mol{sup -1}) or elevated ({approximately}650 {mu}mol mol{sup -1}) levels of CO{sub 2}. To simulate natural defoliation, a subset of the seedlings within each CO{sub 2} treatment also had 50 % of their foliage clipped in late June. During the growing season there were three sequential harvests. The first was coincident with defoliation, followed by a mid-season harvest in early August and a final harvest after leaf senescence. Allocational, morphological and physiological determinants of growth were measured at each harvest. This is the first of two years of CO{sub 2} exposure, and preliminary analyses indicate an increase in both photosynthesis and growth for trembling aspen and sugar maple. However, after accounting for initial growth differences, the magnitude of this enhancement appears to have diminished over the course of the growing season, which can largely be explained by changes in physiological response. Interestingly, there was no growth {open_quotes}acclimation{close_quotes} to an enriched-CO{sub 2} environment for sugar maple seedlings that had been artificially defoliated.

  10. Space Physiology within an Exercise Physiology Curriculum

    ERIC Educational Resources Information Center

    Carter, Jason R.; West, John B.

    2013-01-01

    Compare and contrast strategies remain common pedagogical practices within physiological education. With the support of an American Physiological Society Teaching Career Enhancement Award, we have developed a junior- or senior-level undergraduate curriculum for exercise physiology that compares and contrasts the physiological adaptations of…

  11. Use Of Absolute Function And Its Associates In Formation And `Redevelopment' Of Mathematical Models In Some Plant-Related Quantitative Physiology: Salinity Effects On Leaf Development Of Schefflera arboricola And Harvest Index In Rice

    NASA Astrophysics Data System (ADS)

    Selamat, Ahmad; Awang, Yahya; Mohamed, Mahmud T. M.; Wahab, Zakaria; Osman, Mohammad

    2008-01-01

    The roles of quantitative physiology are becoming more apparent and crucial in the era of ICT recently. As based on the rate-related variables, most of the mathematical models are in the form of `non-linear' function in describing the responses or the observed within-plant processes outcomes versus time. Even though if some responses change in a drastic manner at certain response point within a biological unit or space of a plant system, the response curve `should' be dependent on a continuous independent variable range in a specified period of determination where biologically `should not' functioned by independent variable range having `IF' statement(s). Subjected to nutrient concentration of high salinity (6.0 mS cm-1), the leaf turgidity (measured as leaf surface area) of S. arboricola which initially was described by one form of the logistic growth functions [(y = 1/(a+be-cx)] abruptly reduced as explained by a model having terms of Absolute function (ABS) containing tan-1(x) and its parameter of leaf life expectancy as affected by high salinity growing medium at a certain point of days after planting. This yielded an overall function of y = 1/(a+be-cx)-A[tan-1{(x-B)/D}+ABS(tan-1{(x-B)/D})]E, where a, b, c, A, B, D, and E are constants that most of them can be `biologically' interpreted. The constant B is the point similar to `IF statement' as normally used in other mathematical functions. Plants subjected to lower salinity status (<3.0 mS cm-1) were only having function of y = 1/(a+be-cx). In the harvest index or HI (economic yield/above ground biomass) study of 20 rice varieties grown over two planting seasons, the long flattened tails at both sides of a peak in the middle of function of y = R+B(T+ABS(B-x))e-k(T+ABS(B-x)) had indicated that those varieties maturing at 123 to 133 days after transplanting were having high HI values. In our observation, Absolute (ABS) function coupled with some terms could be used in the formation of some mathematical functions

  12. Potassium physiology.

    PubMed

    Thier, S O

    1986-04-25

    Potassium is the most abundant exchangeable cation in the body. It exists predominantly in the intracellular fluid at concentrations of 140 to 150 meq/liter and in the extracellular fluid at concentrations of 3.5 to 5 meq/liter. The maintenance of the serum potassium concentration is a complex bodily function and results from the balance between intake, excretion, and distribution between intracellular and extracellular space. Ingested potassium is virtually completely absorbed from and minimally excreted through the intestine under nonpathologic circumstances. Renal excretion of potassium, which is the major chronic protective mechanism against abnormalities in potassium balance, depends on filtration, reabsorption, and a highly regulated distal nephron secretory process. Factors regulating potassium secretion include prior potassium intake, intracellular potassium, delivery of sodium chloride and poorly reabsorbable anions to the distal nephron, the urine flow rate, hormones such as aldosterone and beta-catecholamines, and the integrity of the renal tubular cell. The maintenance of distribution between the inside and outside of cells depends on the integrity of the cell membrane and its pumps, osmolality, pH, and the hormones insulin, aldosterone, beta 2-catecholamines, alpha-catecholamines, and prostaglandins. Both distribution across cell membranes and/or renal excretion of potassium may be altered by pharmacologic agents such as diuretics, alpha- and beta-catechol antagonists and agonists, depolarizing agents, and digitalis. Problems with hypokalemia and hyperkalemia can be analyzed on the basis of potassium physiology and pharmacology; proper treatment depends on an accurate analysis.

  13. Effects of zinc addition to a copper-contaminated vineyard soil on sorption of Zn by soil and plant physiological responses.

    PubMed

    Tiecher, Tadeu L; Ceretta, Carlos A; Tiecher, Tales; Ferreira, Paulo A A; Nicoloso, Fernando T; Soriani, Hilda H; Rossato, Liana V; Mimmo, Tanja; Cesco, Stefano; Lourenzi, Cledimar R; Giachini, Admir J; Brunetto, Gustavo

    2016-07-01

    The occurrence of high levels of Cu in vineyard soils is often the result of intensive use of fungicides for the preventive control of foliar diseases and can cause toxicity to plants. Nowadays many grape growers in Southern Brazil have replaced Cu-based with Zn-based products. The aim of the study was to evaluate whether the increase in Zn concentration in a soil with high Cu contents can interfere with the dynamics of these elements, and if this increase in Zn may cause toxicity to maize (Zea mays L.). Soil samples were collected in two areas, one in a vineyard with more than 30 years of cultivation and high concentration of Cu and the other on a natural grassland area adjacent to the vineyard. Different doses of Cu and Zn were added to the soil, and the adsorption isotherms were built following the Langmuir's model. In a second experiment, the vineyard soil was spiked with different Zn concentrations (0, 30, 60, 90, 180, and 270mg Zn kg(-1)) in 3kg pots where maize was grown in a greenhouse for 35 days. When Cu and Zn were added together, there was a reduction in the quantities adsorbed, especially for Zn. Zn addition decreased the total plant dry matter and specific leaf mass. Furthermore, with the increase in the activity of catalase, an activation of the antioxidant system was observed. However, the system was not sufficiently effective to reverse the stress levels imposed on soil, especially in plants grown in the highest doses of Zn. At doses higher than 90Znmgkg(-1) in the Cu-contaminated vineyard soil, maize plants were no longer able to activate the protection mechanism and suffered from metal stress, resulting in suppressed dry matter yields due to impaired functioning of the photosynthetic apparatus and changes in the enzymatic activity of plants. Replacement of Cu- by Zn-based fungicides to avoid Cu toxicity has resulted in soil vineyards contaminated with these metals and damaging of plant photosynthetic apparatus and enzyme activity.

  14. Some physiological measurements on growth, pod yields and polyamines in leaves of chili plants (Capsicum annuum cv. Hua Reua) in relation to applied organic manures and chemical fertilisers.

    PubMed

    Rapatsa, J; Terapongtanakorn, S

    2010-03-15

    The experiment was carried out at the Faculty of Agriculture, Ubon Ratchathani University during November 2006 to July 2007. A Completely Randomized Design (CRD) with four replications was used. Six treatments were allocated into two experimental fields, i.e., field A, animal manures added soil. Field B, chemical fertilizers added soil and both fields have been used for chili cultivation for more than 5 years and they belong to Warin soil series (Oxic Paleustults). The results showed that mean values of soil pH and organic matter % of field A were much higher than field B but mean values of nitrogen % and phosphorus were much higher for field B than field A. Exchangeable potassium were inadequately available in all treatments. All treatments of field B gave excessive amounts of available phosphorus at a toxic level. T3 of field A gave higher plant height, total dry weight plant(-1), pod fresh and dry weights plant(-1) than T5 of field B. Of overall results in terms of growth and yields of chili plants, field A gave much better advantages over field B. The CO2 uptake and CO2 in leaves were higher for field A than field B. Polyamines of putrescine (Put), spermidine (Spd) and spermine (Spm) of T2 were affected by stress conditions due to previous applied chemical fertilisers. Available phosphorus mean values in most treatments were excessively available. Amounts of polyamines in chili leaves due to the added organic manure and chemical fertilizers (T3 up to T6) were not cleared.

  15. Effects of Trichothecene Production on the Plant Defense Response and Fungal Physiology: Overexpression of the Trichoderma arundinaceum tri4 Gene in T. harzianum

    PubMed Central

    Cardoza, R. E.; McCormick, S. P.; Malmierca, M. G.; Olivera, E. R.; Alexander, N. J.; Monte, E.

    2015-01-01

    Trichothecenes are fungal sesquiterpenoid compounds, the majority of which have phytotoxic activity. They contaminate food and feed stocks, resulting in potential harm to animals and human beings. Trichoderma brevicompactum and T. arundinaceum produce trichodermin and harzianum A (HA), respectively, two trichothecenes that show different bioactive properties. Both compounds have remarkable antibiotic and cytotoxic activities, but in addition, trichodermin is highly phytotoxic, while HA lacks this activity when analyzed in vivo. Analysis of Fusarium trichothecene intermediates led to the conclusion that most of them, with the exception of the hydrocarbon precursor trichodiene (TD), have a detectable phytotoxic activity which is not directly related to the structural complexity of the intermediate. In the present work, the HA intermediate 12,13-epoxytrichothec-9-ene (EPT) was produced by expression of the T. arundinaceum tri4 gene in a transgenic T. harzianum strain that already produces TD after transformation with the T. arundinaceum tri5 gene. Purified EPT did not show antifungal or phytotoxic activity, while purified HA showed both antifungal and phytotoxic activities. However, the use of the transgenic T. harzianum tri4 strain induced a downregulation of defense-related genes in tomato plants and also downregulated plant genes involved in fungal root colonization. The production of EPT by the transgenic tri4 strain raised levels of erg1 expression and reduced squalene accumulation while not affecting levels of ergosterol. Together, these results indicate the complex interactions among trichothecene intermediates, fungal antagonists, and host plants. PMID:26150463

  16. Effects of Trichothecene Production on the Plant Defense Response and Fungal Physiology: Overexpression of the Trichoderma arundinaceum tri4 Gene in T. harzianum.

    PubMed

    Cardoza, R E; McCormick, S P; Malmierca, M G; Olivera, E R; Alexander, N J; Monte, E; Gutiérrez, S

    2015-09-01

    Trichothecenes are fungal sesquiterpenoid compounds, the majority of which have phytotoxic activity. They contaminate food and feed stocks, resulting in potential harm to animals and human beings. Trichoderma brevicompactum and T. arundinaceum produce trichodermin and harzianum A (HA), respectively, two trichothecenes that show different bioactive properties. Both compounds have remarkable antibiotic and cytotoxic activities, but in addition, trichodermin is highly phytotoxic, while HA lacks this activity when analyzed in vivo. Analysis of Fusarium trichothecene intermediates led to the conclusion that most of them, with the exception of the hydrocarbon precursor trichodiene (TD), have a detectable phytotoxic activity which is not directly related to the structural complexity of the intermediate. In the present work, the HA intermediate 12,13-epoxytrichothec-9-ene (EPT) was produced by expression of the T. arundinaceum tri4 gene in a transgenic T. harzianum strain that already produces TD after transformation with the T. arundinaceum tri5 gene. Purified EPT did not show antifungal or phytotoxic activity, while purified HA showed both antifungal and phytotoxic activities. However, the use of the transgenic T. harzianum tri4 strain induced a downregulation of defense-related genes in tomato plants and also downregulated plant genes involved in fungal root colonization. The production of EPT by the transgenic tri4 strain raised levels of erg1 expression and reduced squalene accumulation while not affecting levels of ergosterol. Together, these results indicate the complex interactions among trichothecene intermediates, fungal antagonists, and host plants.

  17. Novel roles of SoxR, a transcriptional regulator from Xanthomonas campestris, in sensing redox-cycling drugs and regulating a protective gene that have overall implications for bacterial stress physiology and virulence on a host plant.

    PubMed

    Mahavihakanont, Aekkapol; Charoenlap, Nisanart; Namchaiw, Poommaree; Eiamphungporn, Warawan; Chattrakarn, Sorayut; Vattanaviboon, Paiboon; Mongkolsuk, Skorn

    2012-01-01

    In Xanthomonas campestris pv. campestris, SoxR likely functions as a sensor of redox-cycling drugs and as a transcriptional regulator. Oxidized SoxR binds directly to its target site and activates the expression of xcc0300, a gene that has protective roles against the toxicity of redox-cycling compounds. In addition, SoxR acts as a noninducible repressor of its own expression. X. campestris pv. campestris requires SoxR both for protection against redox-cycling drugs and for full virulence on a host plant. The X. campestris model of the gene regulation and physiological roles of SoxR represents a novel variant of existing bacterial SoxR models.

  18. Effect of zinc and lead on the physiological and biochemical properties of aquatic plant Lemna minor: its potential role in phytoremediation

    NASA Astrophysics Data System (ADS)

    Jayasri, M. A.; Suthindhiran, K.

    2016-01-01

    Plants have gained importance in situ bioremediation of heavy metals. In the present study, different concentrations of zinc (Zn2+) (0.5, 5, 10, 15, 20 mg/l) and lead (Pb2+) (1, 2, 4, 6, 8 mg/l) were used to evaluate metal tolerance level of Lemna minor. L.minor were exposed to metals for 4 days and tested for its dry to fresh weight ratio (DW/FW), photosynthetic pigments production and protein content. The oxidative damage was detected by measuring catalase activity. L.minor showed tolerance against Zn2+ and Pb2+ at a concentration of 10 and 4 mg/l, respectively. Among the metals, Pb2+ showed a significant toxicity at 8 mg/l. High concentration (20 mg/l of Zn2+ and 8 mg/l of Pb2+) of the metals displayed a considerable negative effect on soluble proteins (13 fold decrease with Zn2+ and 4 fold decrease with Pb2+) and photosynthetic pigments (twofold decrease with Zn2+ and onefold decrease with Pb2+) and lead to a consequent reduction in number of fronds. Further, the catalase was greatly increased (twofold decrease with Zn2+ and sixfold decrease with Pb2+) under metal stress. The results indicate that L.minor withstands Zn2+ and Pb2+ toxicity up to the concentration of 10 and 4 mg/l, respectively. Hence, the metal tolerant property of this plant shall be exploited for bioremediation of Zinc and Lead in polluted water. Further, the detailed and wide range of heavy metal toxicity studies should be done to reveal the possible use of this plant on large scale bioremediation purpose.

  19. Evaluation of the Morpho-physiology characteristics of maize inbred lines introduced from CIMMYT to identify the best candidates for planting in acidic soil in Jasinga, Indonesia

    NASA Astrophysics Data System (ADS)

    Lubis, K.; Sutjahjo, S. H.; Syukur, M.; Trikoesoemaningtyas

    2016-08-01

    Technological developments and climate change have affected crop planting strategies. For example, maize production has expanded to sub-optimal lands, including acidic soil common in areas like Indonesia. Breeding programs have created inbred lines of maize introduced from CIMMYT; they were tested locally in acidic soils to determine their adaptability and tolerance mechanisms. Breeds CLA 46 and NEI 9008 were found to be excellent candidates for acidic soil due to their ASI, high number of grains per year, and suitable dry seed weight.

  20. Physiological and biochemical responses in the leaves of two mangrove plant seedlings (Kandelia candel and Bruguiera gymnorrhiza) exposed to multiple heavy metals.

    PubMed

    Huang, Guo-Yong; Wang, You-Shao

    2010-10-15

    The accumulation of heavy metals and their effect on photosynthetic pigments, proline, glutathione (GSH) and phytochelatins (PCs-SH) were studied in the leaves of two mangrove plants seedlings (Kandelia candel and Bruguiera gymnorrhiza) grown for 30 days in the nutrient solution containing four different concentrations of Cd(2+), Pb(2+) and Hg(2+) (T(1), T(2), T(3) and T(4)). An increase in Cd, Pb and Hg content was found in the leaves of both species exposed to multiple heavy metal stress, whereas higher heavy metal levels (>T(1)) led to a remarkable breakdown of chlorophyll in the leaves of both species. The content of proline, GSH and PCs-SH in the leaves of both species exhibited a significant increase in response to heavy metal stress, at least under most of experimental conditions. Increased contents of proline, GSH and PCs-SH in metal-treated plants suggest that metal tolerance in both K. candel and B. gymnorrhiza might be associated to the efficiency of these antioxidants. Moreover, proline, GSH and PCs-SH in K. candel may play more important role in ameliorating the effect of heavy metal toxicity than those in B. gymnorrhiza.

  1. Abrupt plant physiological changes in southern New Zealand at the termination of the Mi-1 event reflect shifts in hydroclimate and pCO2

    NASA Astrophysics Data System (ADS)

    Reichgelt, Tammo; D'Andrea, William J.; Fox, Bethany R. S.

    2016-12-01

    A rise in atmospheric CO2 is believed to be necessary for the termination of large-scale glaciations. Although the Antarctic Ice Sheet is estimated to have melted from ∼125% to ∼50% its modern size, there is thus far no evidence for an increase in atmospheric CO2 associated with the Mi-1 glacial termination in the earliest Miocene. Here, we present evidence from a high-resolution terrestrial record of leaf physiological change in southern New Zealand for an abrupt increase in atmospheric CO2 coincident with the termination of the Mi-1 glaciation and lasting approximately 20 kyr. Quantitative pCO2 estimates, made using a leaf gas exchange model, suggest that atmospheric CO2 levels may have doubled during this period, from 516 ± 111ppm to 1144 ± 410ppm, and subsequently returned back to 425 ± 53ppm. The 20-kyr interval with high pCO2 estimates is also associated with a period of increased moisture supply to southern New Zealand, inferred from carbon and hydrogen isotopes of terrestrial leaf waxes. The results provide the first high-resolution record of terrestrial environmental change at the Oligocene/Miocene boundary, document a ∼20 kyr interval of elevated pCO2 and increased local moisture availability, and provide insight into ecosystem response to a major orbitally driven climatic transition.

  2. [Investigations on the physiology of the glands of carnivorous plants : IV. The kinetics of chloride secretion by the gland tissue of Nepenthes].

    PubMed

    Lüttge, U

    1966-03-01

    The transport of chloride in isolated tissue from Nepenthes pitchers was investigated using (36)Cl(-), an Aminco-Cotlove chloride-titrator for the determinations of Cl(-) concentrations, and KCN and AsO 4 (-) -as metabolic inhibitors.The tissue was brought in contact with different experimental solutions (=medium). The surface corresponding to the outside of the pitchers was cut with a razor blade to remove the cutinized epidermal layer. At this surface the Cl(-) uptake from the medium is a metabolic process which depends on the Cl(-)-concentration of the medium in a manner that corresponds to the MICHAELIS-MENTEN kinetics. The Michaelis-constant of this transport step was 3×10(-2)M. The Cl(-)-efflux into the medium, however, is a passive process.The opposite surface of the tissue slices (corresponding to the inside of the pitchers) carries the glands. The chloride secretion taking place here is also dependent on metabolism. In vitro it occurs even when a high gradient of chloride concentration has been set up between the medium and the solution which is in contact with the glands. In vivo the Cl(-)-concentration of the pitcher fluid and the amount of Cl(-) per gram of tissue water are almost equal.The rôle of chloride in the physiology of Nepenthes is still under investigation, A correlation between the chloride content of the pitcher fluid and its enzymatic activity (Casein-test), however, could already be demonstrated.

  3. The root application of a purified leonardite humic acid modifies the transcriptional regulation of the main physiological root responses to Fe deficiency in Fe-sufficient cucumber plants.

    PubMed

    Aguirre, Elena; Elena, Aguirre; Leménager, Diane; Diane, Leménager; Bacaicoa, Eva; Eva, Bacaicoa; Fuentes, Marta; Marta, Fuentes; Baigorri, Roberto; Roberto, Baigorri; Zamarreño, Angel Ma; García-Mina, José Ma

    2009-03-01

    The aim of this study is to investigate the effect of a well-characterized purified humic acid (non-measurable concentrations of the main plant hormones were detected) on the transcriptional regulation of the principal molecular agents involved in iron assimilation. To this end, non-deficient cucumber plants were treated with different concentrations of a purified humic acid (PHA) (2, 5, 100 and 250 mg of organic carbonL(-1)) and harvested 4, 24, 48, 76 and 92 h from the onset of the treatment. At harvest times, the mRNA transcript accumulation of CsFRO1 encoding for Fe(III) chelate-reductase (EC 1.16.1.7); CsHa1 and CsHa2 encoding for plasma membrane H+-ATPase (EC 3.6.3.6); and CsIRT1 encoding for Fe(II) high-affinity transporter, was quantified by real-time RT-PCR. Meanwhile, the respective enzyme activity of the Fe(III) chelate-reductase and plasma membrane H+-ATPase was also investigated. The results obtained indicated that PHA root treatments affected the regulation of the expression of the studied genes, but this effect was transient and differed (up-regulation or down-regulation) depending on the genes studied. Thus, principally the higher doses of PHA caused a transient increase in the expression of the CsHa2 isoform for 24 and 48 h whereas the CsHa1 isoform was unaffected or down-regulated. These effects were accompanied by an increase in the plasma membrane H+-ATPase activity for 4, 48 and 96 h. Likewise, PHA root treatments (principally the higher doses) up-regulated CsFRO1 and CsIRT1 expression for 48 and 72 h; whereas these genes were down-regulated by PHA for 96 h. These effects were associated with an increase in the Fe(III) chelate-reductase activity for 72 h. These effects were not associated with a significant decrease in the Fe root or leaf concentrations, although an eventual effect on the Fe root assimilation pattern cannot be ruled out. These results stress the close relationships between the effects of humic substances on plant development

  4. [Human physiology: kidney].

    PubMed

    Natochin, Iu V

    2010-01-01

    The content of human physiology as an independent part of current physiology is discussed. Substantiated is the point that subjects of human physiology are not only special sections of physiology where functions are inherent only in human (physiology of intellectual activity, speech, labor, sport), but also in peculiarities of functions, specificity of regulation of each of physiological systems. By the example of physiology of kidney and water-salt balance there are shown borders of norm, peculiarities of regulation in human, new chapters of renal physiology which have appeared in connection with achievements of molecular physiology.

  5. UV-B and UV-C pre-treatments induce physiological changes and artemisinin biosynthesis in Artemisia annua L. - an antimalarial plant.

    PubMed

    Rai, Rashmi; Meena, Ram Prasad; Smita, Shachi Shuchi; Shukla, Aparna; Rai, Sanjay Kumar; Pandey-Rai, Shashi

    2011-12-02

    Present study was undertaken to investigate if short-term UV-B (4.2 kJ m(-2) day(-1)) and UV-C (5.7 kJ m(-2) day(-1)), pre-treatments can induce artemisinin biosynthesis in Artemisia annua. Twenty-one day old Artemisia seedlings were subjected to short-term (14 days) UV pre-treatment in an environmentally controlled growth chamber and then transplanted to the field under natural conditions. Treatment of A. annua with artificial UV-B and UV-C radiation not only altered the growth responses, biomass, pigment content and antioxidant enzyme activity but enhanced the secondary metabolites (artemisinin and flavonoid) content at all developmental stages as compared to non-irradiated plants. The extent of oxidative damage was measured in terms of the activities of enzymes such as catalase, superoxide dismutase and ascorbate peroxidase. Reinforcement in the antioxidative defense system seems to be a positive response of plants in ameliorating the negative effects of UV-B and UV-C radiations. While the carotenoid content was elevated, the chlorophyll content decreased under UV-B and UV-C pre-treatments. The reverse transcription PCR analysis of the genes associated in artemisinin/isoprenoid biosynthesis like 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), cytochrome P450 oxidoreductase (CPR) and amorpha-4,11-diene synthase (ADS) genes at different growth stages revealed UV induced significant over-expression of the above protein genes. UV-B and UV-C pre-treatments, led to an increase in the concentrations of artemisinin at full bloom stage by 10.5% and 15.7% than that of the control respectively. Thus, the result of our study suggests that short term UV-B pre-treatment of seedlings in greenhouse prior to transplantation into the field enhances artemisinin production with lesser yield related damages as compared to UV-C radiation in A. annua.

  6. South American Leaf Blight of the Rubber Tree (Hevea spp.): New Steps in Plant Domestication using Physiological Features and Molecular Markers

    PubMed Central

    Lieberei, Reinhard

    2007-01-01

    Background Rubber trees (Hevea spp.) are perennial crops of Amazonian origin that have been spread over the whole tropical belt to guarantee worldwide production of natural rubber. This crop plant has found its place in many national economies of producing countries, and although its domestication by selection of suitable genotypes was very slow, it contributes a lot to the welfare of small farmers worldwide. Its development is limited by severe diseases. In South America, the main fungal disease of rubber trees is the South American leaf blight (SALB) caused by the ascomycete Microcyclus ulei. This fungus inhibits natural rubber production on a commercial scale in South and Central America. Scope The disease is still restricted to its continent of origin, but its potential to be distributed around the world rises with every transcontinental airline connection that directly links tropical regions. The need to develop control measures against the disease is an urgent task and must be carried out on an international scale. All control efforts so far taken since 1910 have ended in a miserable failure. Even the use of modern systemic fungicides and use of greatly improved application techniques have failed to prevent large losses and dieback of trees. The results of research dealing with both the disease and the pathosystem over more than 50 years are summarized and placed into perspective. Future Prospects A detailed knowledge of this host–pathogen combination requires understanding of the dynamics of Hevea leaf development, the biochemical potential for cyanide liberation, and molecular data for several types of resistance factors. Resolution of the Hevea–SALB problem may serve as a model for future host–pathogen studies of perennial plants requiring a holistic approach. PMID:17650512

  7. Manipulation of the hypocotyl sink activity by reciprocal grafting of two Raphanus sativus varieties: its effects on morphological and physiological traits of source leaves and whole-plant growth.

    PubMed

    Sugiura, Daisuke; Betsuyaku, Eriko; Terashima, Ichiro

    2015-12-01

    To reveal whether hypocotyl sink activities are regulated by the aboveground parts, and whether physiology and morphology of source leaves are affected by the hypocotyl sink activities, we conducted grafting experiments using two Raphanus sativus varieties with different hypocotyl sink activities. Comet (C) and Leafy (L) varieties with high and low hypocotyl sink activities were reciprocally grafted and resultant plants were called by their scion and stock such as CC, LC, CL and LL. Growth, leaf mass per area (LMA), total non-structural carbohydrates (TNCs) and photosynthetic characteristics were compared among them. Comet hypocotyls in CC and LC grew well regardless of the scions, whereas Leafy hypocotyls in CL and LL did not. Relative growth rate was highest in LL and lowest in CC. Photosynthetic capacity was correlated with Rubisco (ribulose 1·5-bisphosphate carboxylase/oxygenase) content but unaffected by TNC. High C/N ratio and accumulation of TNC led to high LMA and structural LMA. These results showed that the hypocotyl sink activity was autonomously regulated by hypocotyl and that the down-regulation of photosynthesis was not induced by TNC. We conclude that the change in the sink activity alters whole-plant growth through the changes in both biomass allocation and leaf morphological characteristics in R. sativus.

  8. Molecular architecture of plant thylakoids under physiological and light stress conditions: a study of lipid-light-harvesting complex II model membranes.

    PubMed

    Janik, Ewa; Bednarska, Joanna; Zubik, Monika; Puzio, Michal; Luchowski, Rafal; Grudzinski, Wojciech; Mazur, Radoslaw; Garstka, Maciej; Maksymiec, Waldemar; Kulik, Andrzej; Dietler, Giovanni; Gruszecki, Wieslaw I

    2013-06-01

    In this study, we analyzed multibilayer lipid-protein membranes composed of the photosynthetic light-harvesting complex II (LHCII; isolated from spinach [Spinacia oleracea]) and the plant lipids monogalcatosyldiacylglycerol and digalactosyldiacylglycerol. Two types of pigment-protein complexes were analyzed: those isolated from dark-adapted leaves (LHCII) and those from leaves preilluminated with high-intensity light (LHCII-HL). The LHCII-HL complexes were found to be partially phosphorylated and contained zeaxanthin. The results of the x-ray diffraction, infrared imaging microscopy, confocal laser scanning microscopy, and transmission electron microscopy revealed that lipid-LHCII membranes assemble into planar multibilayers, in contrast with the lipid-LHCII-HL membranes, which form less ordered structures. In both systems, the protein formed supramolecular structures. In the case of LHCII-HL, these structures spanned the multibilayer membranes and were perpendicular to the membrane plane, whereas in LHCII, the structures were lamellar and within the plane of the membranes. Lamellar aggregates of LHCII-HL have been shown, by fluorescence lifetime imaging microscopy, to be particularly active in excitation energy quenching. Both types of structures were stabilized by intermolecular hydrogen bonds. We conclude that the formation of trans-layer, rivet-like structures of LHCII is an important determinant underlying the spontaneous formation and stabilization of the thylakoid grana structures, since the lamellar aggregates are well suited to dissipate excess energy upon overexcitation.

  9. The physiology of potassium in crop production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potassium plays a major role in the basic functions of plant growth and development. In addition, K is also involved in numerous physiological functions related to plant health and tolerance to biotic and abiotic stress. However, deficiencies occur widely resulting in poor growth, lost yield and red...

  10. Maintaining A Physiological Blood Glucose Level with ‘Glucolevel’, A Combination of Four Anti-Diabetes Plants Used in the Traditional Arab Herbal Medicine

    PubMed Central

    Fulder, Stephen; Khalil, Khaled; Azaizeh, Hassan; Kassis, Eli; Saad, Bashar

    2008-01-01

    Safety and anti-diabetic effects of Glucolevel, a mixture of dry extract of leaves of the Juglans regia L, Olea europea L, Urtica dioica L and Atriplex halimus L were evaluated using in vivo and in vitro test systems. No sign of toxic effects (using LDH assay) were seen in cultured human fibroblasts treated with increasing concentrations of Glucolevel. Similar observations were seen in vivo studies using rats (LD50: 25 g/kg). Anti-diabetic effects were evidenced by the augmentation of glucose uptake by yeast cells (2-folds higher) and by inhibition of glucose intestinal absorption (∼49%) in a rat gut-segment. Furthermore, treatment with Glucolevel of Streptozotocin-induced diabetic rats for 2–3 weeks showed a significant reduction in glucose levels [above 400 ± 50 mg/dl to 210 ± 22 mg/dl (P < 0.001)] and significantly improved sugar uptake during the glucose tolerance test, compared with positive control. In addition, glucose levels were tested in sixteen human volunteers, with the recent onset of type 2 diabetes mellitus, who received Glucolevel tablets 1 × 3 daily for a period of 4 weeks. Within the first week of Glucolevel consumption, baseline glucose levels were significantly reduced from 290 ± 40 to 210 ± 20 mg/dl. At baseline, a subgroup of eleven of these subjects had glucose levels below 300 mg% and the other subgroup had levels ≥ 300 mg%. Clinically acceptable glucose levels were achieved during the 2–3 weeks of therapy in the former subgroup and during the 4th week of therapy in the latter subgroup. No side effect was reported. In addition, a significant reduction in hemoglobin A1C values (8.2 ± 1.03 to 6.9 ± 0.94) was found in six patients treated with Glucolevel. Results demonstrate safety, tolerability and efficacy of herbal combinations of four plants that seem to act differently but synergistically to regulate glucose-homeostasis. PMID:18955212

  11. Plant Biology Science Projects.

    ERIC Educational Resources Information Center

    Hershey, David R.

    This book contains science projects about seed plants that deal with plant physiology, plant ecology, and plant agriculture. Each of the projects includes a step-by-step experiment followed by suggestions for further investigations. Chapters include: (1) "Bean Seed Imbibition"; (2) "Germination Percentages of Different Types of Seeds"; (3)…

  12. Genome-Wide Linkage Mapping of QTL for Yield Components, Plant Height and Yield-Related Physiological Traits in the Chinese Wheat Cross Zhou 8425B/Chinese Spring

    PubMed Central

    Gao, Fengmei; Wen, Weie; Liu, Jindong; Rasheed, Awais; Yin, Guihong; Xia, Xianchun; Wu, Xiaoxia; He, Zhonghu

    2015-01-01

    Identification of genes for yield components, plant height (PH), and yield-related physiological traits and tightly linked molecular markers is of great importance in marker-assisted selection (MAS) in wheat breeding. In the present study, 246 F8 RILs derived from the cross of Zhou 8425B/Chinese Spring were genotyped using the high-density Illumina iSelect 90K single nucleotide polymorphism (SNP) assay. Field trials were conducted at Zhengzhou and Zhoukou of Henan Province, during the 2012–2013 and 2013–2014 cropping season under irrigated conditions, providing data for four environments. Analysis of variance (ANOVA) of agronomic and physiological traits revealed significant differences (P < 0.01) among RILs, environments, and RILs × environments interactions. Broad-sense heritabilities of all traits including thousand kernel weight (TKW), PH, spike length (SL), kernel number per spike (KNS), spike number/m2 (SN), normalized difference in vegetation index at anthesis (NDVI-A) and at 10 days post-anthesis (NDVI-10), SPAD value of chlorophyll content at anthesis (Chl-A) and at 10 days post-anthesis (Chl-10) ranged between 0.65 and 0.94. A linkage map spanning 3609.4 cM was constructed using 5636 polymorphic SNP markers, with an average chromosome length of 171.9 cM and marker density of 0.64 cM/marker. A total of 866 SNP markers were newly mapped to the hexaploid wheat linkage map. Eighty-six QTL for yield components, PH, and yield-related physiological traits were detected on 18 chromosomes except 1D, 5D, and 6D, explaining 2.3–33.2% of the phenotypic variance. Ten stable QTL were identified across four environments, viz. QTKW.caas-6A.1, QTKW.caas-7AL, QKNS.caas-4AL, QSN.caas-1AL.1, QPH.caas-4BS.2, QPH.caas-4DS.1, QSL.caas-4AS, QSL.caas-4AL.1, QChl-A.caas-5AL, and QChl-10.caas-5BL. Meanwhile, 10 QTL-rich regions were found on chromosome 1BS, 2AL (2), 3AL, 4AL (2), 4BS, 4DS, 5BL, and 7AL exhibiting pleiotropic effects. These QTL or QTL clusters are tightly

  13. Space physiology within an exercise physiology curriculum.

    PubMed

    Carter, Jason R; West, John B

    2013-09-01

    Compare and contrast strategies remain common pedagogical practices within physiological education. With the support of an American Physiological Society Teaching Career Enhancement Award, we have developed a junior- or senior-level undergraduate curriculum for exercise physiology that compares and contrasts the physiological adaptations of chronic terrestrial exercise (TEx) and microgravity (μG). We used a series of peer-reviewed publications to demonstrate that many of the physiological adaptations to TEx and μG are opposite. For example, TEx typically improves cardiovascular function and orthostatic tolerance, whereas μG can lead to declines in both. TEx leads to muscle hypertrophy, and μG elicits muscle atrophy. TEx increases bone mineral density and red blood cell mass, whereas μG decreases bone mineral density and red blood cell mass. Importantly, exercise during spaceflight remains a crucial countermeasure to limit some of these adverse physiological adaptations to μG. This curriculum develops critical thinking skills by dissecting peer-reviewed articles and discussing the strengths and weaknesses associated with simulated and actual μG studies. Moreover, the curriculum includes studies on both animals and humans, providing a strong translational component to the curriculum. In summary, we have developed a novel space physiology curriculum delivered during the final weeks of an exercise physiology course in which students gain critical new knowledge that reinforces key concepts presented throughout the semester.

  14. Flooding and Plant Growth

    PubMed Central

    VISSER, E. J. W.; VOESENEK, L. A. C. J.; VARTAPETIAN, B. B.; JACKSON, M. B.

    2003-01-01

    This Special Issue is based on the 7th Conference of the International Society for Plant Anaerobiosis (ISPA), held in Nijmegen, The Netherlands, 12–16 June 2001. The papers describe and analyse many of the responses that plants display when subjected to waterlogging of the soil or deeper submergence. These responses may be injurious or adaptive, and are discussed at various levels of organizational complexity ranging from ecosystem processes, through individual plants to single cells. The research incorporates molecular biology and genetics, cell physiology, biochemistry, hormone physiology, whole plant physiology, plant demography and ecology. The study of the damage to young rice plants caused by submergence, especially as experienced in the rainfed lowlands of Asia, is comprehensively addressed. This work integrates various specialized approaches ranging from agronomy to molecular genetics, and demonstrates how plant biology can be harnessed to improve stress tolerance in an important crop species while simultaneously improving basic understanding of tolerance mechanisms and plant processes.

  15. Electronic plants

    PubMed Central

    Stavrinidou, Eleni; Gabrielsson, Roger; Gomez, Eliot; Crispin, Xavier; Nilsson, Ove; Simon, Daniel T.; Berggren, Magnus

    2015-01-01

    The roots, stems, leaves, and vascular circuitry of higher plants are responsible for conveying the chemical signals that regulate growth and functions. From a certain perspective, these features are analogous to the contacts, interconnections, devices, and wires of discrete and integrated electronic circuits. Although many attempts have been made to augment plant function with electroactive materials, plants’ “circuitry” has never been directly merged with electronics. We report analog and digital organic electronic circuits and devices manufactured in living plants. The four key components of a circuit have been achieved using the xylem, leaves, veins, and signals of the plant as the template and integral part of the circuit elements and functions. With integrated and distributed electronics in plants, one can envisage a range of applications including precision recording and regulation of physiology, energy harvesting from photosynthesis, and alternatives to genetic modification for plant optimization. PMID:26702448

  16. Physiological Information Database (PID)

    EPA Science Inventory

    EPA has developed a physiological information database (created using Microsoft ACCESS) intended to be used in PBPK modeling. The database contains physiological parameter values for humans from early childhood through senescence as well as similar data for laboratory animal spec...

  17. Chewing Over Physiology Integration

    ERIC Educational Resources Information Center

    Abdulkader, Fernando; Azevedo-Martins, Anna Karenina; de Arcisio Miranda, Manoel; Brunaldi, Kellen

    2005-01-01

    An important challenge for both students and teachers of physiology is to integrate the differentareas in which physiological knowledge is didactically divided. In developing countries, such an issue is even more demanding, because budget restrictions often affect the physiology program with laboratory classes being the first on the list when it…

  18. Microarrays for global expression constructed with a low redundancy set of 27,500 sequenced cDNAs representing an array of developmental stages and physiological conditions of the soybean plant

    PubMed Central

    Vodkin, Lila O; Khanna, Anupama; Shealy, Robin; Clough, Steven J; Gonzalez, Delkin Orlando; Philip, Reena; Zabala, Gracia; Thibaud-Nissen, Françoise; Sidarous, Mark; Strömvik, Martina V; Shoop, Elizabeth; Schmidt, Christina; Retzel, Ernest; Erpelding, John; Shoemaker, Randy C; Rodriguez-Huete, Alicia M; Polacco, Joseph C; Coryell, Virginia; Keim, Paul; Gong, George; Liu, Lei; Pardinas, Jose; Schweitzer, Peter

    2004-01-01

    Background Microarrays are an important tool with which to examine coordinated gene expression. Soybean (Glycine max) is one of the most economically valuable crop species in the world food supply. In order to accelerate both gene discovery as well as hypothesis-driven research in soybean, global expression resources needed to be developed. The applications of microarray for determining patterns of expression in different tissues or during conditional treatments by dual labeling of the mRNAs are unlimited. In addition, discovery of the molecular basis of traits through examination of naturally occurring variation in hundreds of mutant lines could be enhanced by the construction and use of soybean cDNA microarrays. Results We report the construction and analysis of a low redundancy 'unigene' set of 27,513 clones that represent a variety of soybean cDNA libraries made from a wide array of source tissue and organ systems, developmental stages, and stress or pathogen-challenged plants. The set was assembled from the 5' sequence data of the cDNA clones using cluster analysis programs. The selected clones were then physically reracked and sequenced at the 3' end. In order to increase gene discovery from immature cotyledon libraries that contain abundant mRNAs representing storage protein gene families, we utilized a high density filter normalization approach to preferentially select more weakly expressed cDNAs. All 27,513 cDNA inserts were amplified by polymerase chain reaction. The amplified products, along with some repetitively spotted control or 'choice' clones, were used to produce three 9,728-element microarrays that have been used to examine tissue specific gene expression and global expression in mutant isolines. Conclusions Global expression studies will be greatly aided by the availability of the sequence-validated and low redundancy cDNA sets described in this report. These cDNAs and ESTs represent a wide array of developmental stages and physiological

  19. Plant Systems Biology (editorial)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In June 2003, Plant Physiology published an Arabidopsis special issue devoted to plant systems biology. The intention of Natasha Raikhel and Gloria Coruzzi, the two editors of this first-of-its-kind issue, was ‘‘to help nucleate this new effort within the plant community’’ as they considered that ‘‘...

  20. Fundaments of plant cybernetics.

    PubMed

    Zucconi, F

    2001-01-01

    A systemic approach is proposed for analyzing plants' physiological organization and cybernesis. To this end, the plant is inspected as a system, starting from the integration of crown and root systems, and its impact on a number of basic epigenetic events. The approach proves to be axiomatic and facilitates the definition of the principles behind the plant's autonomous control of growth and reproduction.

  1. Advanced Plant Habitat (APH)

    NASA Technical Reports Server (NTRS)

    Richards, Stephanie E. (Compiler); Levine, Howard G.; Reed, David W.

    2016-01-01

    The Advanced Plant Habitat (APH) hardware will be a large growth volume plant habitat, capable of hosting multigenerational studies, in which environmental variables (e.g., temperature, relative humidity, carbon dioxide level light intensity and spectral quality) can be tracked and controlled in support of whole plant physiological testing and Bio-regenerative Life Support System investigations.

  2. Physiological investigation of gold nanorods toward watermelon.

    PubMed

    Wan, Yujie; Li, Junli; Ren, Hongxuan; Huang, Jin; Yuan, Hong

    2014-08-01

    The objective of the present study was to evaluate the phytotoxicity and oxidant stress of the gold nanorods toward watermelon, and hence give a quantitative risk assessment of both seeds and plants phase. The seed germination, the activity of antioxidant enzymes, and the contents of soluble protein and malondialdehyde (MDA) have been measured while the plant roots were observed by transmission electron microscopy (TEM). It was found that the gold nanorods significantly promoted the root elongation. Furthermore, the results on the enzymes activities of plant indicated that oxidative stress happened in the plant treated with gold nanorods. However, the gold nanorods resulted in the phytotoxicity toward plant especially at high concentration. The TEM images of the plant roots with and without the treatment of gold nanorods showed the significant different size of starch granules. In conclusion, significant physiological changes of plant occurred after treatment with the gold nanorods.

  3. Cassava biology and physiology.

    PubMed

    El-Sharkawy, Mabrouk A

    2004-11-01

    Cassava or manioc (Manihot esculenta Crantz), a perennial shrub of the New World, currently is the sixth world food crop for more than 500 million people in tropical and sub-tropical Africa, Asia and Latin America. It is cultivated mainly by resource-limited small farmers for its starchy roots, which are used as human food either fresh when low in cyanogens or in many processed forms and products, mostly starch, flour, and for animal feed. Because of its inherent tolerance to stressful environments, where other food crops would fail, it is often considered a food-security source against famine, requiring minimal care. Under optimal environmental conditions, it compares favorably in production of energy with most other major staple food crops due to its high yield potential. Recent research at the Centro Internacional de Agricultura Tropical (CIAT) in Colombia has demonstrated the ability of cassava to assimilate carbon at very high rates under high levels of humidity, temperature and solar radiation,which correlates with productivity across all environments whether dry or humid. When grown on very poor soils under prolonged drought for more than 6 months, the crop reduce both its leaf canopy and transpiration water loss, but its attached leaves remain photosynthetically active, though at greatly reduced rates. The main physiological mechanism underlying such a remarkable tolerance to drought was rapid stomatal closure under both atmospheric and edaphic water stress, protecting the leaf against dehydration while the plant depletes available soil water slowly during long dry periods. This drought tolerance mechanism leads to high crop water use efficiency values. Although the cassava fine root system is sparse, compared to other crops, it can penetrate below 2 m soil,thus enabling the crop to exploit deep water if available. Leaves of cassava and wild Manihot possess elevated activities of the C4 enzyme PEP carboxylase but lack the leaf Kranz anatomy typical of C4

  4. Physiological Disorders of Pear Shoot Cultures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Physiological disorders are some of the most difficult challenges in micropropagation. Little is known of the causes of plant growth disorders which include callus formation, hyperhydricity, shoot tip necrosis, leaf lesions, epinasty, fasciation and hypertrophy. During our study of mineral nutritio...

  5. Physiology of sport.

    PubMed

    Maughan, Ron

    2007-07-01

    The elite athlete represents the extreme of the human gene pool, where genetic endowment is developed by an intensive training programme. Sport encompasses many different activities, calling for different physical and mental attributes. Understanding the physiology of exercise provides insights into normal physiological function.

  6. Space physiology and medicine

    SciTech Connect

    Nicogossian, A.E.; Parker J.F. Jr.

    1982-01-01

    The state of knowledge in space physiology and medicine are reviewed. Overviews of manned space flight, the space environment, spaceflight systems and procedures, physiological adaptation to space flight, health maintenance of space crew members, and medical problems of space flight are presented.

  7. Phun Week: Understanding Physiology

    ERIC Educational Resources Information Center

    Limson, Mel; Matyas, Marsha Lakes

    2009-01-01

    Topics such as sports, exercise, health, and nutrition can make the science of physiology relevant and engaging for students. In addition, many lessons on these topics, such as those on the cardiovascular, respiratory, and digestive systems, align with national and state life science education standards. Physiology Understanding Week (PhUn…

  8. Microbial physiology vol. 29

    SciTech Connect

    Rose, A.H. ); Tempest, D.W. )

    1988-01-01

    This book contains the following chapters: Hydrogen metabolism in Rhizobium: energetics, regulation, enzymology and genetics; The physiology and biochemistry of pili; Carboxysomes and ribulose bisphosphate carboxylase/oxygenase; Archaebacteria: the comparative enzymology of their central metabolic pathways; and Physiology of lipoteichoic acids in bacteria.

  9. Reproduction, Physiology and Biochemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter focuses on the reproduction, physiology, and biochemistry of the root-knot nematodes. The extensive amount of information on the reproduction and cytogenetics of species of Meloidogyne contrasts with the limited information on physiology, biochemistry, and biochemical pathways. In commo...

  10. Progress in physiological optics.

    PubMed

    Boynton, R M

    1967-08-01

    A survey is made of the current state of physiological optics, broadly defined as equated with visual science. After a survey of some historical and definitional matters, recent progress in a number of areas is critically reviewed. Finally, seven examples of important recent discoveries in physiological optics are given.

  11. Physiology in conservation translocations

    PubMed Central

    Tarszisz, Esther; Dickman, Christopher R.; Munn, Adam J.

    2014-01-01

    Conservation translocations aim to restore species to their indigenous ranges, protect populations from threats and/or reinstate ecosystem functions. They are particularly important for the conservation and management of rare and threatened species. Despite tremendous efforts and advancement in recent years, animal conservation translocations generally have variable success, and the reasons for this are often uncertain. We suggest that when little is known about the physiology and wellbeing of individuals either before or after release, it will be difficult to determine their likelihood of survival, and this could limit advancements in the science of translocations for conservation. In this regard, we argue that physiology offers novel approaches that could substantially improve translocations and associated practices. As a discipline, it is apparent that physiology may be undervalued, perhaps because of the invasive nature of some physiological measurement techniques (e.g. sampling body fluids, surgical implantation). We examined 232 publications that dealt with translocations of terrestrial vertebrates and aquatic mammals and, defining ‘success’ as high or low, determined how many of these studies explicitly incorporated physiological aspects into their protocols and monitoring. From this review, it is apparent that physiological evaluation before and after animal releases could progress and improve translocation/reintroduction successes. We propose a suite of physiological measures, in addition to animal health indices, for assisting conservation translocations over the short term and also for longer term post-release monitoring. Perhaps most importantly, we argue that the incorporation of physiological assessments of animals at all stages of translocation can have important welfare implications by helping to reduce the total number of animals used. Physiological indicators can also help to refine conservation translocation methods. These approaches fall

  12. Journal of Gravitational Physiology. Volume 10, No. 1

    NASA Technical Reports Server (NTRS)

    Fuller, Charles (Editor); Cogoli, Augusto (Editor); Hargens, Alan R. (Editor); Smith, Arthur H. (Editor); Alberts, Jeffrey (Editor); Baldwin, Kenneth (Editor); Bjurstedt, Hilding (Editor); Blomqvist, C. Gunnar (Editor); Burton, Russell (Editor); Cardus, David (Editor)

    2003-01-01

    The topics addressed in this issue include: 1) Biosatellites: Past, Present, and Future; 2) Plant Physiology; 3) Neural/Sensory; 4) Musculoskeletal; 5) Endocrinology/Immunology; 6) Development; 7) Cardiovascular; 8) Countermeasures/Applied; 9) Technical.

  13. Urban Plantings: 'Living Laboratories' for Climate Change Response.

    PubMed

    Farrell, Claire; Szota, Christopher; Arndt, Stefan K

    2015-10-01

    Urban plantings are not only valuable resources for understanding 'urban plant physiology' but are 'living laboratories' for understanding plant response to climate change. Therefore, we encourage researchers who currently work in natural ecosystems to consider how urban plantings could enhance their research into plant physiological responses to a changing climate.

  14. Physiological effects of Squash vein yellowing virus infection on watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Squash vein yellowing virus (SqVYV) is the cause of viral watermelon vine decline. In this study, watermelon plants of different ages were inoculated with SqVYV to characterize the physiological response to infection and provide new insights into watermelon vine decline. Physiological responses to...

  15. Endogenous Pyrogen Physiology.

    ERIC Educational Resources Information Center

    Beisel, William R.

    1980-01-01

    Discusses the physiology of endogenous pyrogen (EP), the fever-producing factor of cellular origin. Included are: its hormone-like role, its molecular nature, bioassay procedures, cellular production and mechanisms of EP action. (SA)

  16. Physiological Disorders in Closed, Controlled Environment Crops

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Morrow, Robert C.

    2010-01-01

    This slide presentation reviews some of the physiological disorders that affect crops grown in closed controlled environments. A physiological disorder is understood to be a problem resulting from the influence of environmental and horticultural factors on plan development other than a problem caused by a pathogen or some other abiotic cause. The topics that are addressed are: (1) Calcium-Related Disorders (2) Oedema (Intumescence) (3) Long-Photoperiod Injury (4) Light Spectral Quality Effects (5) Super-Elevated CO2 Injuries (6) Ethylene (7) Other Disorders (8) Considerations for Closed Space Environments. Views of plant with the disorders are shown.

  17. The conservation physiology of seed dispersal.

    PubMed

    Ruxton, Graeme D; Schaefer, H Martin

    2012-06-19

    At a time when plant species are experiencing increasing challenges from climate change, land-use change, harvesting and invasive species, dispersal has become a very important aspect of plant conservation. Seed dispersal by animals is particularly important because some animals disperse seeds to suitable sites in a directed fashion. Our review has two aims: (i) to highlight the various ways plant dispersal by animals can be affected by current anthropogenic change and (ii) to show the important role of plant and (particularly) animal physiology in shaping seed-dispersal interactions. We argue that large-bodied seed dispersers may be particularly important for plant conservation because seed dispersal of large-seeded plants is often more specialized and because large-bodied animals are targeted by human exploitation and have smaller population sizes. We further argue that more specialized seed-dispersal systems on island ecosystems might be particularly at risk from climate change both owing to small population sizes involved but also owing to the likely thermal specialization, particularly on tropical islands. More generally, the inherent vulnerability of seed-dispersal mutualisms to disruption driven by environmental change (as well as their ubiquity) demands that we continue to improve our understanding of their conservation physiology.

  18. The conservation physiology of seed dispersal

    PubMed Central

    Ruxton, Graeme D.; Schaefer, H. Martin

    2012-01-01

    At a time when plant species are experiencing increasing challenges from climate change, land-use change, harvesting and invasive species, dispersal has become a very important aspect of plant conservation. Seed dispersal by animals is particularly important because some animals disperse seeds to suitable sites in a directed fashion. Our review has two aims: (i) to highlight the various ways plant dispersal by animals can be affected by current anthropogenic change and (ii) to show the important role of plant and (particularly) animal physiology in shaping seed–dispersal interactions. We argue that large-bodied seed dispersers may be particularly important for plant conservation because seed dispersal of large-seeded plants is often more specialized and because large-bodied animals are targeted by human exploitation and have smaller population sizes. We further argue that more specialized seed-dispersal systems on island ecosystems might be particularly at risk from climate change both owing to small population sizes involved but also owing to the likely thermal specialization, particularly on tropical islands. More generally, the inherent vulnerability of seed-dispersal mutualisms to disruption driven by environmental change (as well as their ubiquity) demands that we continue to improve our understanding of their conservation physiology. PMID:22566677

  19. Plant Water Relations.

    ERIC Educational Resources Information Center

    Tomley, David

    1982-01-01

    Some simple field investigations on plant water relations are described which demonstrate links between physiological and external environmental factors. In this way, a more complex picture of a plant and how it functions within its habitat and the effects the environment has on it can be built up. (Author/JN)

  20. Plants without arbuscular mycorrhizae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    P is second to N as the most limiting element for plant growth. Plants have evolved a number of effective strategies to acquire P and grow in a P-limited environment. Physiological, biochemical, and molecular studies of P-deficiency adaptations that occur in non-mycorrhizal species have provided str...

  1. Assessing physiological complexity.

    PubMed

    Burggren, W W; Monticino, M G

    2005-09-01

    Physiologists both admire and fear complexity, but we have made relatively few attempts to understand it. Inherently complex systems are more difficult to study and less predictable. However, a deeper understanding of physiological systems can be achieved by modifying experimental design and analysis to account for complexity. We begin this essay with a tour of some mathematical views of complexity. After briefly exploring chaotic systems, information theory and emergent behavior, we reluctantly conclude that, while a mathematical view of complexity provides useful perspectives and some narrowly focused tools, there are too few generally practical take-home messages for physiologists studying complex systems. Consequently, we attempt to provide guidelines as to how complex systems might be best approached by physiologists. After describing complexity based on the sum of a physiological system's structures and processes, we highlight increasingly refined approaches based on the pattern of interactions between structures and processes. We then provide a series of examples illustrating how appreciating physiological complexity can improve physiological research, including choosing experimental models, guiding data collection, improving data interpretations and constructing more rigorous system models. Finally, we conclude with an invitation for physiologists, applied mathematicians and physicists to collaborate on describing, studying and learning from studies of physiological complexity.

  2. Changes in the flux of carbon between plants and soil microorganisms at elevated CO{sub 2}: Physiological processes with ecosystem-level implications. Progress report, [August 15, 1994--August 14, 1995

    SciTech Connect

    Zak, D.R.; Pregitzer, K.S.

    1995-05-15

    This report presents the details of a research program that investigated the impacts of elevated carbon dioxide on terrestrial ecosystems. This report focused on the effects of plant carbon allocation, microbial activity, soil changes, and nitrogen dynamics.

  3. Human physiology in space

    NASA Technical Reports Server (NTRS)

    Vernikos, J.

    1996-01-01

    The universality of gravity (1 g) in our daily lives makes it difficult to appreciate its importance in morphology and physiology. Bone and muscle support systems were created, cellular pumps developed, neurons organised and receptors and transducers of gravitational force to biologically relevant signals evolved under 1g gravity. Spaceflight provides the only microgravity environment where systematic experimentation can expand our basic understanding of gravitational physiology and perhaps provide new insights into normal physiology and disease processes. These include the surprising extent of our body's dependence on perceptual information, and understanding the effect and importance of forces generated within the body's weightbearing structures such as muscle and bones. Beyond this exciting prospect is the importance of this work towards opening the solar system for human exploration. Although both appear promising, we are only just beginning to taste what lies ahead.

  4. Circadian physiology of metabolism.

    PubMed

    Panda, Satchidananda

    2016-11-25

    A majority of mammalian genes exhibit daily fluctuations in expression levels, making circadian expression rhythms the largest known regulatory network in normal physiology. Cell-autonomous circadian clocks interact with daily light-dark and feeding-fasting cycles to generate approximately 24-hour oscillations in the function of thousands of genes. Circadian expression of secreted molecules and signaling components transmits timing information between cells and tissues. Such intra- and intercellular daily rhythms optimize physiology both by managing energy use and by temporally segregating incompatible processes. Experimental animal models and epidemiological data indicate that chronic circadian rhythm disruption increases the risk of metabolic diseases. Conversely, time-restricted feeding, which imposes daily cycles of feeding and fasting without caloric reduction, sustains robust diurnal rhythms and can alleviate metabolic diseases. These findings highlight an integrative role of circadian rhythms in physiology and offer a new perspective for treating chronic diseases in which metabolic disruption is a hallmark.

  5. Human physiology in space.

    PubMed

    Vernikos, J

    1996-12-01

    The universality of gravity (1 g) in our daily lives makes it difficult to appreciate its importance in morphology and physiology. Bone and muscle support systems were created, cellular pumps developed, neurons organised and receptors and transducers of gravitational force to biologically relevant signals evolved under 1g gravity. Spaceflight provides the only microgravity environment where systematic experimentation can expand our basic understanding of gravitational physiology and perhaps provide new insights into normal physiology and disease processes. These include the surprising extent of our body's dependence on perceptual information, and understanding the effect and importance of forces generated within the body's weightbearing structures such as muscle and bones. Beyond this exciting prospect is the importance of this work towards opening the solar system for human exploration. Although both appear promising, we are only just beginning to taste what lies ahead.

  6. Physiological Signal Conditioner

    NASA Technical Reports Server (NTRS)

    Friedericks, C.

    1999-01-01

    Sensors 2000! is developing a Physiological Signal Conditioner (PSC) for monitoring of astronauts in the ISS Human Research Facility. The PSC is battery powered and worn by the crew. The Engineering Development Unit (PSC EDU) and the form-and-fit PSC Tooling Model will be displayed along with associated graphics and text explanations. Results of a recent advanced PSC-2 feasibility study will be presented. The presentation will stimulate discussion of the functional capabilities of a wireless, crew worn Physiological Signal Conditioner. Application of advanced technology to meet the conflicting demands of size, power, and functional capability will be of interest.

  7. Specifications Physiological Monitoring System

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The operation of a physiological monitoring system (PMS) is described. Specifications were established for performance, design, interface, and test requirements. The PMS is a compact, microprocessor-based system, which can be worn in a pack on the body or may be mounted on a Spacelab rack or other appropriate structure. It consists of two modules, the Data Control Unit (DCU) and the Remote Control/Display Unit (RCDU). Its purpose is to collect and distribute data from physiological experiments in the Spacelab and in the Orbiter.

  8. Measuring sap flow in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sap flow measurements provide a powerful tool for quantifying plant water use and monitoring qualitative physiological responses of plants to environmental conditions. As such, sap flow methods are widely employed to invesitgate the agronomic, ecological and hydrological outcomes of plant growth. T...

  9. Modeling plant growth and development.

    PubMed

    Prusinkiewicz, Przemyslaw

    2004-02-01

    Computational plant models or 'virtual plants' are increasingly seen as a useful tool for comprehending complex relationships between gene function, plant physiology, plant development, and the resulting plant form. The theory of L-systems, which was introduced by Lindemayer in 1968, has led to a well-established methodology for simulating the branching architecture of plants. Many current architectural models provide insights into the mechanisms of plant development by incorporating physiological processes, such as the transport and allocation of carbon. Other models aim at elucidating the geometry of plant organs, including flower petals and apical meristems, and are beginning to address the relationship between patterns of gene expression and the resulting plant form.

  10. Programmable physiological infusion

    NASA Technical Reports Server (NTRS)

    Howard, W. H.; Young, D. R.; Adachi, R. R. (Inventor)

    1974-01-01

    A programmable physiological infusion device and method are provided wherein a program source, such as a paper tape, is used to actuate an infusion pump in accordance with a desired program. The system is particularly applicable for dispensing calcium in a variety of waveforms.

  11. Integrative Physiology of Fasting.

    PubMed

    Secor, Stephen M; Carey, Hannah V

    2016-03-15

    Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.

  12. The Virtual Physiological Human

    PubMed Central

    Coveney, Peter V.; Diaz, Vanessa; Hunter, Peter; Kohl, Peter; Viceconti, Marco

    2011-01-01

    The Virtual Physiological Human is synonymous with a programme in computational biomedicine that aims to develop a framework of methods and technologies to investigate the human body as a whole. It is predicated on the transformational character of information technology, brought to bear on that most crucial of human concerns, our own health and well-being.

  13. Physiology of Sleep.

    PubMed

    Carley, David W; Farabi, Sarah S

    2016-02-01

    IN BRIEF Far from a simple absence of wakefulness, sleep is an active, regulated, and metabolically distinct state, essential for health and well-being. In this article, the authors review the fundamental anatomy and physiology of sleep and its regulation, with an eye toward interactions between sleep and metabolism.

  14. Physiology of lactation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The breast changes in size, shape, and function during puberty, pregnancy, and lactation. The physiology of lactation is reviewed here. The breast is composed of fat and connective tissue that supports a tubuloalveolar structure. During development, anatomic changes involving new lobule formation an...

  15. Physiology of Breastfeeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This powerpoint presentation summaries physiology of lactation and the impact of a variety of clinical practices on lactation from delivery through weaning. Factors that inhibit lactogenesis stage II are explained, including retained placenta, excess blood loss during delivery, and hypoplastic brea...

  16. Simulated Exercise Physiology Laboratories.

    ERIC Educational Resources Information Center

    Morrow, James R., Jr.; Pivarnik, James M.

    This book consists of a lab manual and computer disks for either Apple or IBM hardware. The lab manual serves as "tour guide" for the learner going through the various lab experiences. The manual contains definitions, proper terminology, and other basic information about physiological principles. It is organized so a step-by-step procedure may be…

  17. Renal physiology of pregnancy.

    PubMed

    Cheung, Katharine L; Lafayette, Richard A

    2013-05-01

    Pregnancy involves remarkable orchestration of physiologic changes. The kidneys are central players in the evolving hormonal milieu of pregnancy, responding and contributing to the changes in the environment for the pregnant woman and fetus. The functional impact of pregnancy on kidney physiology is widespread, involving practically all aspects of kidney function. The glomerular filtration rate increases 50% with subsequent decrease in serum creatinine, urea, and uric acid values. The threshold for thirst and antidiuretic hormone secretion are depressed, resulting in lower osmolality and serum sodium levels. Blood pressure drops approximately 10 mmHg by the second trimester despite a gain in intravascular volume of 30% to 50%. The drop in systemic vascular resistance is multifactorial, attributed in part to insensitivity to vasoactive hormones, and leads to activation of the renin-aldosterone-angiostensin system. A rise in serum aldosterone results in a net gain of approximately 1000 mg of sodium. A parallel rise in progesterone protects the pregnant woman from hypokalemia. The kidneys increase in length and volume, and physiologic hydronephrosis occurs in up to 80% of women. This review will provide an understanding of these important changes in kidney physiology during pregnancy, which is fundamental in caring for the pregnant patient.

  18. Starting Physiology: Bioelectrogenesis

    ERIC Educational Resources Information Center

    Baptista, Vander

    2015-01-01

    From a Cartesian perspective of rational analysis, the electric potential difference across the cell membrane is one of the fundamental concepts for the study of physiology. Unfortunately, undergraduate students often struggle to understand the genesis of this energy gradient, which makes the teaching activity a hard task for the instructor. The…

  19. Physiology in microgravity.

    PubMed

    West, J B

    2000-07-01

    Studies of physiology in microgravity are remarkably recent, with almost all the data being obtained in the past 40 years. The first human spaceflight did not take place until 1961. Physiological measurements in connection with the early flights were crude, but, in the past 10 years, an enormous amount of new information has been obtained from experiments on Spacelab. The United States and Soviet/Russian programs have pursued different routes. The US has mainly concentrated on relatively short flights but with highly sophisticated equipment such as is available in Spacelab. In contrast, the Soviet/Russian program concentrated on first the Salyut and then the Mir space stations. These had the advantage of providing information about long-term exposure to microgravity, but the degree of sophistication of the measurements in space was less. It is hoped that the International Space Station will combine the best of both approaches. The most important physiological changes caused by microgravity include bone demineralization, skeletal muscle atrophy, vestibular problems causing space motion sickness, cardiovascular problems resulting in postflight orthostatic intolerance, and reductions in plasma volume and red cell mass. Pulmonary function is greatly altered but apparently not seriously impaired. Space exploration is a new frontier with long-term missions to the moon and Mars not far away. Understanding the physiological changes caused by long-duration microgravity remains a daunting challenge.

  20. Avian reproductive physiology

    USGS Publications Warehouse

    Gee, G.F.; Gibbons, Edward F.; Durrant, Barbara S.; Demarest, Jack

    1995-01-01

    Knowledge of the many physiological factors associated with egg production , fertility, incubation, and brooding in nondomestic birds is limited. Science knows even less about reproduction in most of the 238 endangered or threatened birds. This discussion uses studies of nondomestic and, when necessary, domestic birds to describe physiological control of reproduction. Studies of the few nondomestic avian species show large variation in physiological control of reproduction. Aviculturists, in order to successfully propagate an endangered bird, must understand the bird's reproductive peculiarities. First, investigators can do studies with carefully chosen surrogate species, but eventually they need to confirm the results in the target endangered bird. Studies of reproduction in nondomestic birds increased in the last decade. Still, scientists need to do more comparative studies to understand the mechanisms that control reproduction in birds. New technologies are making it possible to study reproductive physiology of nondomestic species in less limiting ways. These technologies include telemetry to collect information without inducing stress on captives (Howey et al., 1987; Klugman, 1987), new tests for most of the humoral factors associated with reproduction, and the skill to collect small samples and manipulate birds without disrupting the physiological mechanisms (Bercovitz et al., 1985). Managers are using knowledge from these studies to improve propagation in zoological parks, private and public propagation facilities, and research institutions. Researchers need to study the control of ovulation, egg formation, and oviposition in the species of nondomestic birds that lay very few eggs in a season, hold eggs in the oviduct for longer intervals, or differ in other ways from the more thoroughly studied domestic birds. Other techniques that would enhance propagation for nondomestlc birds include tissue culture of cloned embryonic cells, cryopreservation of embryos

  1. Pathologic and physiologic phimosis

    PubMed Central

    McGregor, Thomas B.; Pike, John G.; Leonard, Michael P.

    2007-01-01

    OBJECTIVE To review the differences between physiologic and pathologic phimosis, review proper foreskin care, and discuss when it is appropriate to seek consultation regarding a phimotic foreskin. SOURCES OF INFORMATION This paper is based on selected findings from a MEDLINE search for literature on phimosis and circumcision referrals and on our experience at the Children’s Hospital of Eastern Ontario Urology Clinic. MeSH headings used in our MEDLINE search included “phimosis,” “referral and consultation,” and “circumcision.” Most of the available articles about phimosis and foreskin referrals were retrospective reviews and cohort studies (levels II and III evidence). MAIN MESSAGE Phimosis is defined as the inability to retract the foreskin. Differentiating between physiologic and pathologic phimosis is important, as the former is managed conservatively and the latter requires surgical intervention. Great anxiety exists among patients and parentsregarding non-retractile foreskins. Most phimosis referrals seen in pediatric urology clinics are normal physiologically phimotic foreskins. Referrals of patients with physiologic phimosis to urology clinics can create anxiety about the need for surgery among patients and parents, while unnecessarily expanding the waiting list for specialty assessment. Uncircumcised penises require no special care. With normal washing, using soap and water, and gentle retraction during urination and bathing, most foreskins will become retractile over time. CONCLUSION Physiologic phimosis is often seen by family physicians. These patients and their parents require reassurance of normalcy and reinforcement of proper preputial hygiene. Consultation should be sought when evidence of pathologic phimosis is present, as this requires surgical management. PMID:17872680

  2. Foliar delta(13)C and delta(18)O reveal differential physiological responses of canopy foliage to pre-planting weed control in a young spotted gum (Corymbia citriodora subsp. Variegata) plantation.

    PubMed

    Huang, Zhiqun; Xu, Zhihong; Blumfield, Timothy J; Bubb, Ken

    2008-10-01

    Weed control may improve the growth of forest plantations by influencing soil water and nutrient availability, but our knowledge of leaf-level physiological responses to weed control at different within-canopy positions is limited for tropical and subtropical plantations. Foliar carbon (delta(13)C) and oxygen (delta(18)O) isotope compositions, gas exchange, and nitrogen (N(mass)) and phosphorus (P(mass)) concentrations at four canopy positions were assessed in a young spotted gum (Corymbia citriodora subsp. Variegata (F. Muell.) A.R. Bean & M.W. McDonald) plantation subjected to either weed control or no weed control treatment, to test if leaves at different positions within the tree canopy had the same physiological responses to the weed control treatment. Weed control increased foliar delta(13)C but lowered delta(18)O in the upper-outer and upper-inner canopy, indicating that weed control resulted in a higher foliar photosynthetic capacity at upper-canopy positions, a conclusion confirmed by gas exchange measurements. The increased photosynthetic capacity resulting from weed control can be explained by an increase in foliar N(mass). In the lower-outer canopy, weed control reduced foliar delta(13)C while lowering delta(18)O even more than in the upper-canopy, suggesting strong enhancement of the partial pressure of CO(2) in the leaf intercellular spaces and of foliar stomatal conductance in lower-canopy foliage. This conclusion was supported by gas exchange measurements. Foliar photosynthesis in the lower-inner canopy showed no significant response to weed control. The finding that leaves at different canopy positions differ in their physiological responses to weed control highlights the need to consider the canopy position effect when examining competition for soil nutrient and water resources between weeds and trees.

  3. Fruit Calcium: Transport and Physiology

    PubMed Central

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  4. [Physiologic effects of hypothermia].

    PubMed

    Kovács, Eniko; Jenei, Zsigmond; Horváth, Anikó; Gellér, László; Szilágyi, Szabolcs; Király, Akos; Molnár, Levente; Sótonyi, Péter; Merkely, Béla; Zima, Endre

    2011-01-30

    Therapeutic use of hypothermia has come to the frontline in the past decade again in the prevention and in mitigation of neurologic impairment. The application of hypothermia is considered as a successful therapeutic measure not just in neuro- or cardiac surgery, but also in states causing brain injury or damage. According to our present knowledge this is the only proven therapeutic tool, which improves the neurologic outcome after cardiac arrest, decreasing the oxygen demand of the brain. Besides influencing the nervous system, hypothermia influences the function of the whole organ system. Beside its beneficial effects, it has many side-effects, which may be harmful to the patient. Before using it for a therapeutic purpose, it is very important to be familiar with the physiology and complications of hypothermia, to know, how to prevent and treat its side-effects. The purpose of this article is to summarize the physiologic and pathophysiologic effects of hypothermia.

  5. Hair and Physiological Baldness

    PubMed Central

    Mercantini, Edward S.

    1965-01-01

    Human hair is one of the structures of the body about which little is generally known. Disease affecting the hair is often minimized or ignored by physicians because of lack of knowledge of this rudimentary organ. However, the patient's attitude toward hair loss is very different from the doctor's and he feels great concern about such loss. The development, growth and morphology of human hair are briefly presented. Experimental work which will increase our knowledge of hair growth and loss is reviewed. The various forms of physiological alopecia from birth onward are discussed, with special emphasis on the least-known type of physiological baldness, “male-pattern baldness” in the adult female. PMID:14312445

  6. Physiology of skin.

    PubMed

    Greaves, M W

    1976-07-01

    One of Montagna's greatest contributions to study of the biology of the skin has been his demolition of the artificial walls that traditionally separated the histologist from the physiologist. He has shown that only by relating function with structure can we shed light on the workings of the skin. He has stressed the fallacy of studying a single structural or functional unit in isolation from others. The skin represents an organization of many different functional units, and physiology of skin is the study of this organization. My purpose is to make a personal commentary on the achievements, failures, and prospects of understanding some aspects of the organization of the functional units. Twenty-five years ago, the importance of relating skin to internal organs and systems received much attention. We have long been aware that skin sometimes reacts to internal disease, but only recently has the impact of skin disorders on the circulatory, renal, and gastrointestinal systems been recognized. As a result, our patients are now less likely to suffer from neglect of the whole which follows narrow over-specialized attention to the part. Increased interest in endocrine effects on the skin has revealed that several important physiologic activities of the skin are either partly or wholly regulated by hormones secreted by endocrine glands. Nevertheless, some physiologic activities in skin seems to be independent, their regulation being carried out by local mediating hormones. Other activities involve both central and local regulation. The nature and roles of these two control mechanisms and their interrelation constitute by far the most promising physiologic research in skin.

  7. Tuna comparative physiology.

    PubMed

    Graham, Jeffrey B; Dickson, Kathryn A

    2004-11-01

    Thunniform swimming, the capacity to conserve metabolic heat in red muscle and other body regions (regional endothermy), an elevated metabolic rate and other physiological rate functions, and a frequency-modulated cardiac output distinguish tunas from most other fishes. These specializations support continuous, relatively fast swimming by tunas and minimize thermal barriers to habitat exploitation, permitting niche expansion into high latitudes and to ocean depths heretofore regarded as beyond their range.

  8. Renal phosphate handling: Physiology

    PubMed Central

    Prasad, Narayan; Bhadauria, Dharmendra

    2013-01-01

    Phosphorus is a common anion. It plays an important role in energy generation. Renal phosphate handling is regulated by three organs parathyroid, kidney and bone through feedback loops. These counter regulatory loops also regulate intestinal absorption and thus maintain serum phosphorus concentration in physiologic range. The parathyroid hormone, vitamin D, Fibrogenic growth factor 23 (FGF23) and klotho coreceptor are the key regulators of phosphorus balance in body. PMID:23961477

  9. Molecular biology in physiology

    SciTech Connect

    Chien, S.; Gargus, J.J.

    1987-08-01

    The aim of this symposium on molecular biology in physiology was to introduce molecular biology to physiologists who had relatively little exposure to the new developments in this field, so that they can become conversant on this topic and contribute to the advancement of physiology by incorporating molecular biological approaches as a part of their research arsenal. This report is a review of the symposium, which consisted of two four-part sessions. Each session had four papers. After the discussion of the basic concepts, terminology, and methodology used in molecular biology, it was shown how these basic principles have been applied to the study of the genes encoding two membrane proteins that have important transport functions (band 3 and ATPase). The second half of the symposium consisted of papers on the state-of-the-art developments in the application of molecular biology to the studies of the atrial natriuretic factor and renin genes, adenylate cyclase-coupled adrenergic receptors, acetylcholine receptors and sodium channel, and long-term and short-term memories. The ultimate goal is that these examples will provide an impetus for the opening of new frontiers of research in physiology by taking advantage of the tools developed from recent advances in molecular biology.

  10. Steroid plant hormones: effects outside plant kingdom.

    PubMed

    Zhabinskii, Vladimir N; Khripach, Natalia B; Khripach, Vladimir A

    2015-05-01

    Brassinosteroids (BS) are the first group of steroid-hormonal compounds isolated from and acting in plants. Among numerous physiological effects of BS growth stimulation and adaptogenic activities are especially remarkable. In this review, we provide evidence that BS possess similar types of activity also beyond plant kingdom at concentrations comparable with those for plants. This finding allows looking at steroids from a new point of view: how common are the mechanisms of steroid bioregulation in different types of organisms from protozoa to higher animals.

  11. Plant Habitat (PH)

    NASA Technical Reports Server (NTRS)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  12. Zinc deficiency affects physiological and anatomical characteristics in maize leaves.

    PubMed

    Mattiello, Edson M; Ruiz, Hugo A; Neves, Julio C L; Ventrella, Marília C; Araújo, Wagner L

    2015-07-01

    Zinc (Zn) is an essential microelement involved in several plant physiological processes. Therefore, it is important to identify Zn deficiencies promptly--before extensive damage occurs to the plant. The diagnostic tools that are used to identify Zn deficiencies are very important in areas where Zn deficiencies occur. Such diagnostic tools are vital for nutritional management and fertilizer recommendations. The current study investigated the effects of Zn deficiency on maize plants by recording a number of physiological and anatomical parameters. A Zn omission trial (from 0 to 22 days) was carried out to produce plants that had varying degrees of Zn deficiency. Typical symptoms of Zn deficiency (e.g. chlorotic stripes and purple shades on the edges and leaf sheath) appeared 16 days after the omission of Zn from nutrient solutions. As the time of Zn omission increased, there were significant decreases in net photosynthesis, stomatal conductance, maximal efficiency of photosystem I (evaluated by Fv/Fm), biomass (dry weight) and Zn concentrations in plants. Zinc-deficient plants also had a lower vascular bundle proportion coupled with a higher stomata density. These physiological and anatomical changes negatively impacted plant growth. Moreover, they occurred before visible symptoms of Zn deficiency were observed. Zinc concentrations were recorded for younger leaves, rather than for more mature leaves, which is usually recommended for plant analysis. The results demonstrate that the analysis of Zn in young leaves of maize is a very sensitive indicator of Zn status.

  13. Histidine biosynthesis in plants.

    PubMed

    Stepansky, A; Leustek, T

    2006-03-01

    The study of histidine metabolism has never been at the forefront of interest in plant systems despite the significant role that the analysis of this pathway has played in development of the field of molecular genetics in microbes. With the advent of methods to analyze plant gene function by complementation of microbial auxotrophic mutants and the complete analysis of plant genome sequences, strides have been made in deciphering the histidine pathway in plants. The studies point to a complex evolutionary origin of genes for histidine biosynthesis. Gene regulation studies have indicated novel regulatory networks involving histidine. In addition, physiological studies have indicated novel functions for histidine in plants as chelators and transporters of metal ions. Recent investigations have revealed intriguing connections of histidine in plant reproduction. The exciting new information suggests that the study of plant histidine biosynthesis has finally begun to flower.

  14. Self-discrimination in the tendrils of the vine Cayratia japonica is mediated by physiological connection.

    PubMed

    Fukano, Yuya; Yamawo, Akira

    2015-09-07

    Although self-discrimination has been well documented, especially in animals, self-discrimination in plants has been identified in only a few cases, such as self-incompatibility in flowers and root discrimination. Here, were port a new form of self-discrimination in plants: discrimination by vine tendrils. We found that tendrils of the perennial vine Cayratia japonica were more likely to coil around neighbouring non-self plants than neighbouring self plants in both experimental and natural settings. The higher level of coiling around a physiologically severed self plant compared with that around a physiologically connected self plant suggested that self-discrimination was mediated by physiological coordination between the tendril and the touched plant as reported for self-discrimination in roots. The results highlight the importance of self-discrimination for plant competition not only underground,but also above-ground.

  15. Analog device simulates physiological waveforms

    NASA Technical Reports Server (NTRS)

    Hickman, D. M.

    1964-01-01

    An analog physiological simulator generates representative waveforms for a wide range of physiological conditions. Direct comparison of these waveforms with those from telemetric inputs permits quick detection of signal parameter degradation.

  16. Carotenoids, chemistry, sources and physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter for the Enclyclopedia of Human Nutrition (3rd edition) summarizes the structure, chemical and physiological mechanisms, dietary sources, and metabolism of carotenoids. Carotenoids are a family of phytonutrients which have antioxidant properties under most physiological conditions. Num...

  17. Plant Phenotype Characterization System

    SciTech Connect

    Daniel W McDonald; Ronald B Michaels

    2005-09-09

    This report is the final scientific report for the DOE Inventions and Innovations Project: Plant Phenotype Characterization System, DE-FG36-04GO14334. The period of performance was September 30, 2004 through July 15, 2005. The project objective is to demonstrate the viability of a new scientific instrument concept for the study of plant root systems. The root systems of plants are thought to be important in plant yield and thus important to DOE goals in renewable energy sources. The scientific study and understanding of plant root systems is hampered by the difficulty in observing root activity and the inadequacy of existing root study instrumentation options. We have demonstrated a high throughput, non-invasive, high resolution technique for visualizing plant root systems in-situ. Our approach is based upon low-energy x-ray radiography and the use of containers and substrates (artificial soil) which are virtually transparent to x-rays. The system allows us to germinate and grow plant specimens in our containers and substrates and to generate x-ray images of the developing root system over time. The same plant can be imaged at different times in its development. The system can be used for root studies in plant physiology, plant morphology, plant breeding, plant functional genomics and plant genotype screening.

  18. Genetics and the physiological ecology of conifers

    SciTech Connect

    Mitton, J.B.

    1995-07-01

    Natural selection acts on the diversity of genotypes, adapting populations to their specific environments and driving evolution in response to changes in climate. Genetically based differences in physiology and demography adapt species to alternate environments and produce, along with historical accidents, the present distribution of species. The sorting of conifer species by elevation is so marked that conifers help to define plant communities arranged in elevational bands in the Rocky Mountains. For these reasons, a genetic perspective is necessary to appreciate the evolution of ecophysiological patterns in the coniferous forests of the Rocky Mountains. The fascinating natural history and the economic importance of western conifers have stimulated numerous studies of their ecology, ecological genetics, and geographic variation. These studies yield some generalizations, and present some puzzling contradictions. This chapter focuses on the genetic variability associated with the physiological differences among genotypes in Rocky Mountain conifers. Variation among genotypes in survival, growth, and resistance to herbivores is used to illustrate genetically based differences in physiology, and to suggest the mechanistic studies needed to understand the relationships between genetic and physiological variation.

  19. Asthma Outcomes: Pulmonary Physiology

    PubMed Central

    Tepper, Robert S.; Wise, Robert S.; Covar, Ronina; Irvin, Charles G.; Kercsmar, Carolyn M.; Kraft, Monica; Liu, Mark C.; O’Connor, George T.; Peters, Stephen P.; Sorkness, Ronald; Togias, Alkis

    2014-01-01

    Background Outcomes of pulmonary physiology have a central place in asthma clinical research. Objective At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to provide recommendations on the use of pulmonary function measures as asthma outcomes that should be assessed in a standardized fashion in future asthma clinical trials and studies to allow for cross-study comparisons. Methods Our subcommittee conducted a comprehensive search of PubMed to identify studies that focused on the validation of various airway response tests used in asthma clinical research. The subcommittee classified the instruments as core (to be required in future studies), supplemental (to be used according to study aims and in a standardized fashion), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011. Results A list of pulmonary physiology outcomes that applies to both adults and children older than 6 years was created. These outcomes were then categorized into core, supplemental, and emerging. Spirometric outcomes (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and FEV1/FVC) are proposed as core outcomes for study population characterization, for observational studies, and for prospective clinical trials. Bronchodilator reversibility and pre- and post-bronchodilator FEV1 also are core outcomes for study population characterization and observational studies. Conclusions The subcommittee considers pulmonary physiology outcomes of central importance in asthma and proposes spirometric outcomes as core outcomes for all future NIH-initiated asthma clinical research. PMID:22386510

  20. Gastrointestinal Physiology and Function.

    PubMed

    Greenwood-Van Meerveld, Beverley; Johnson, Anthony C; Grundy, David

    2017-02-08

    The gastrointestinal (GI) system is responsible for the digestion and absorption of ingested food and liquids. Due to the complexity of the GI tract and the substantial volume of material that could be covered under the scope of GI physiology, this chapter briefly reviews the overall function of the GI tract, and discusses the major factors affecting GI physiology and function, including the intestinal microbiota, chronic stress, inflammation, and aging with a focus on the neural regulation of the GI tract and an emphasis on basic brain-gut interactions that serve to modulate the GI tract. GI diseases refer to diseases of the esophagus, stomach, small intestine, colon, and rectum. The major symptoms of common GI disorders include recurrent abdominal pain and bloating, heartburn, indigestion/dyspepsia, nausea and vomiting, diarrhea, and constipation. GI disorders rank among the most prevalent disorders, with the most common including esophageal and swallowing disorders, gastric and peptic ulcer disease, gastroparesis or delayed gastric emptying, irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD). Many GI disorders are difficult to diagnose and their symptoms are not effectively managed. Thus, basic research is required to drive the development of novel therapeutics which are urgently needed. One approach is to enhance our understanding of gut physiology and pathophysiology especially as it relates to gut-brain communications since they have clinical relevance to a number of GI complaints and represent a therapeutic target for the treatment of conditions including inflammatory diseases of the GI tract such as IBD and functional gut disorders such as IBS.

  1. Physiology of Iron Metabolism

    PubMed Central

    Waldvogel-Abramowski, Sophie; Waeber, Gérard; Gassner, Christoph; Buser, Andreas; Frey, Beat M.; Favrat, Bernard; Tissot, Jean-Daniel

    2014-01-01

    Summary A revolution occurred during the last decade in the comprehension of the physiology as well as in the physiopathology of iron metabolism. The purpose of this review is to summarize the recent knowledge that has accumulated, allowing a better comprehension of the mechanisms implicated in iron homeostasis. Iron metabolism is very fine tuned. The free molecule is very toxic; therefore, complex regulatory mechanisms have been developed in mammalian to insure adequate intestinal absorption, transportation, utilization, and elimination. ‘Ironomics’ certainly will be the future of the understanding of genes as well as of the protein-protein interactions involved in iron metabolism. PMID:25053935

  2. Physiological integration enhanced the tolerance of Cynodon dactylon to flooding.

    PubMed

    Li, Z J; Fan, D Y; Chen, F Q; Yuan, Q Y; Chow, W S; Xie, Z Q

    2015-03-01

    Many flooding-tolerant species are clonal plants; however, the effects of physiological integration on plant responses to flooding have received limited attention. We hypothesise that flooding can trigger changes in metabolism of carbohydrates and ROS (reactive oxygen species) in clonal plants, and that physiological integration can ameliorate the adverse effects of stress, subsequently restoring the growth of flooded ramets. In the present study, we conducted a factorial experiment combining flooding to apical ramets and stolon severing (preventing physiological integration) between apical and basal ramets of Cynodon dactylon, which is a stoloniferous perennial grass with considerable flooding tolerance. Flooding-induced responses including decreased root biomass, accumulation of soluble sugar and starch, as well as increased activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX) in apical ramets. Physiological integration relieved growth inhibition, carbohydrate accumulation and induction of antioxidant enzyme activity in stressed ramets, as expected, without any observable cost in unstressed ramets. We speculate that relief of flooding stress in clonal plants may rely on oxidising power and electron acceptors transferred between ramets through physiological integration.

  3. Hormone Profiling in Plant Tissues.

    PubMed

    Müller, Maren; Munné-Bosch, Sergi

    2017-01-01

    Plant hormones are for a long time known to act as chemical messengers in the regulation of physiological processes during a plant's life cycle, from germination to senescence. Furthermore, plant hormones simultaneously coordinate physiological responses to biotic and abiotic stresses. To study the hormonal regulation of physiological processes, three main approaches have been used (1) exogenous application of hormones, (2) correlative studies through measurements of endogenous hormone levels, and (3) use of transgenic and/or mutant plants altered in hormone metabolism or signaling. A plant hormone profiling method is useful to unravel cross talk between hormones and help unravel the hormonal regulation of physiological processes in studies using any of the aforementioned approaches. However, hormone profiling is still particularly challenging due to their very low abundance in plant tissues. In this chapter, a sensitive, rapid, and accurate method to quantify all the five "classic" classes of plant hormones plus other plant growth regulators, such as jasmonates, salicylic acid, melatonin, and brassinosteroids is described. The method includes a fast and simple extraction procedure without time consuming steps as purification or derivatization, followed by optimized ultrahigh-performance liquid chromatography coupled to electrospray ionization-tandem mass spectrometry (UHPLC-MS/MS) analysis. This protocol facilitates the high-throughput analysis of hormone profiling and is applicable to different plant tissues.

  4. Agriculture, physiology and medicine

    SciTech Connect

    Rattazzi, M.C.; Scandalios, J.G.; Whitt, G.S.

    1987-01-01

    This book contains 15 papers. Some of the titles are: Genetics, Expression, and Modification in the Human Alkaline Phosphatases; Sensitive Techniques for the Detection of Genetic Variation in Human Isozymes; The Effect of Heavy Metals on Isozyme Gene Expression in Silen cucubalus; and Plant Genetic Resources: Prediction by Isozyme Markers and Ecology.

  5. Environmental Factors in the Physiology of Abscission

    PubMed Central

    Addicott, Fredrick T.

    1968-01-01

    This paper reviews the physiological effects of the principal environmental factors which can influence the process of leaf abscission. The factors include temperature, light, water, gases, mineral elements, soil conditions, and parasitic organisms. These factors influence a variety of internal physiological conditions and processes which in turn may either accelerate or retard the process of abscission. The most important internal factors include A) sugar, pectin, cellulose, and other carbohydrates; B) energy-yielding respiration; C) enzymic reactions; D) amino acids, purines, and other nitrogenous substances; E) levels of plant hormones; and F) the molecular biological pathway. The current information is consistent with the hypothesis that the environmental factors act in leaf abscission via direct or indirect influences on the synthesis or reaction rate of enzymes. PMID:16657013

  6. The Physiology of Adventitious Roots1

    PubMed Central

    Steffens, Bianka; Rasmussen, Amanda

    2016-01-01

    Adventitious roots are plant roots that form from any nonroot tissue and are produced both during normal development (crown roots on cereals and nodal roots on strawberry [Fragaria spp.]) and in response to stress conditions, such as flooding, nutrient deprivation, and wounding. They are important economically (for cuttings and food production), ecologically (environmental stress response), and for human existence (food production). To improve sustainable food production under environmentally extreme conditions, it is important to understand the adventitious root development of crops both in normal and stressed conditions. Therefore, understanding the regulation and physiology of adventitious root formation is critical for breeding programs. Recent work shows that different adventitious root types are regulated differently, and here, we propose clear definitions of these classes. We use three case studies to summarize the physiology of adventitious root development in response to flooding (case study 1), nutrient deficiency (case study 2), and wounding (case study 3). PMID:26697895

  7. Quo vadis plant hormone analysis?

    PubMed

    Tarkowská, Danuše; Novák, Ondřej; Floková, Kristýna; Tarkowski, Petr; Turečková, Veronika; Grúz, Jiří; Rolčík, Jakub; Strnad, Miroslav

    2014-07-01

    Plant hormones act as chemical messengers in the regulation of myriads of physiological processes that occur in plants. To date, nine groups of plant hormones have been identified and more will probably be discovered. Furthermore, members of each group may participate in the regulation of physiological responses in planta both alone and in concert with members of either the same group or other groups. The ideal way to study biochemical processes involving these signalling molecules is 'hormone profiling', i.e. quantification of not only the hormones themselves, but also their biosynthetic precursors and metabolites in plant tissues. However, this is highly challenging since trace amounts of all of these substances are present in highly complex plant matrices. Here, we review advances, current trends and future perspectives in the analysis of all currently known plant hormones and the associated problems of extracting them from plant tissues and separating them from the numerous potentially interfering compounds.

  8. The panorama of physiological responses and gene expression of whole plant of maize inbred line YQ7-96 at the three-leaf stage under water deficit and re-watering.

    PubMed

    Lu, Hai-Feng; Dong, Hai-Tao; Sun, Chang-Bin; Qing, Dong-Jin; Li, Ning; Wu, Zi-Kai; Wang, Zhi-Qiang; Li, You-Zhi

    2011-10-01

    Changes in water potential, growth elongation, photosynthesis of three-leaf-old seedlings of maize inbred line YQ7-96 under water deficit (WD) for 0.5, 1 and 2 h and re-watering (RW) for 24 h were characterized. Gene expression was analyzed using cDNA microarray covering 11,855 maize unigenes. As for whole maize plant, the expression of WD-regulated genes was characterized by up-regulation. The expression of WD-regulated genes was categorized into eight different patterns, respectively, in leaves and roots. Newly found and WD-affected cellular processes were metabolic process, amino acid and derivative metabolic process and cell death. A great number of the analyzed genes were found to be regulated specifically by RW and commonly by both WD and RW, respectively, in leaves. It is therefore concluded that (1) whole maize plant tolerance to WD, as well as growth recovery from WD, depends at least in part on transcriptional coordination between leaves and roots; (2) WD exerts effects on the maize, especially on basal metabolism; (3) WD could probably affect CO(2) uptake and partitioning, and transport of fixed carbons; (4) WD could likely influence nuclear activity and genome stability; and (5) maize growth recovery from WD is likely involved in some specific signaling pathways related to RW-specific responsive genes.

  9. Network Physiology: Mapping Interactions Between Networks of Physiologic Networks

    NASA Astrophysics Data System (ADS)

    Ivanov, Plamen Ch.; Bartsch, Ronny P.

    The human organism is an integrated network of interconnected and interacting organ systems, each representing a separate regulatory network. The behavior of one physiological system (network) may affect the dynamics of all other systems in the network of physiologic networks. Due to these interactions, failure of one system can trigger a cascade of failures throughout the entire network. We introduce a systematic method to identify a network of interactions between diverse physiologic organ systems, to quantify the hierarchical structure and dynamics of this network, and to track its evolution under different physiologic states. We find a robust relation between network structure and physiologic states: every state is characterized by specific network topology, node connectivity and links strength. Further, we find that transitions from one physiologic state to another trigger a markedly fast reorganization in the network of physiologic interactions on time scales of just a few minutes, indicating high network flexibility in response to perturbations. This reorganization in network topology occurs simultaneously and globally in the entire network as well as at the level of individual physiological systems, while preserving a hierarchical order in the strength of network links. Our findings highlight the need of an integrated network approach to understand physiologic function, since the framework we develop provides new information which can not be obtained by studying individual systems. The proposed system-wide integrative approach may facilitate the development of a new field, Network Physiology.

  10. Physiology of Mycobacteria

    PubMed Central

    Cook, Gregory M.; Berney, Michael; Gebhard, Susanne; Heinemann, Matthias; Cox, Robert A.; Danilchanka, Olga; Niederweis, Michael

    2013-01-01

    Mycobacterium tuberculosis is a prototrophic, metabolically flexible bacterium that has achieved a spread in the human population that is unmatched by any other bacterial pathogen. The success of M. tuberculosis as a pathogen can be attributed to its extraordinary stealth and capacity to adapt to environmental changes throughout the course of infection. These changes include: nutrient deprivation, hypoxia, various exogenous stress conditions and, in the case of the pathogenic species, the intraphagosomal environment. Knowledge of the physiology of M. tuberculosis during this process has been limited by the slow growth of the bacterium in the laboratory and other technical problems such as cell aggregation. Advances in genomics and molecular methods to analyse the M. tuberculosis genome have revealed that adaptive changes are mediated by complex regulatory networks and signals, resulting in temporal gene expression coupled to metabolic and energetic changes. An important goal for bacterial physiologists will be to elucidate the physiology of M. tuberculosis during the transition between the diverse conditions encountered by M. tuberculosis. This review covers the growth of the mycobacterial cell and how environmental stimuli are sensed by this bacterium. Adaptation to different environments is described from the viewpoint of nutrient acquisition, energy generation and regulation. To gain quantitative understanding of mycobacterial physiology will require a systems biology approach and recent efforts in this area are discussed. “It is now 100 years since the first mycobacterium was isolated by Hansen (1874). Somewhat ironically, this was the leprosy bacillus, Mycobacterium leprae, which even today is still resisting all attempts to cultivate it in the laboratory. The tubercle bacillus, M. tuberculosis was not discovered until eight years later (Koch, 1882) and this has remained an object of intensive investigation ever since. The widespread interest in the

  11. Home geriatric physiological measurements.

    PubMed

    Tamura, Toshiyo

    2012-10-01

    In an ageing society, the elderly can be monitored with numerous physiological, physical and passive devices. Sensors can be installed in the home for continuous mobility assistance and unobtrusive disease prevention. This review presents several modern sensors, which improve the quality of life and assist the elderly, disabled people and their caregivers. The main concept of geriatric sensors is that they are capable of providing assistance without limiting or disturbing the subject's daily routine, giving him or her greater comfort, pleasure and well-being. Furthermore, this review includes associated technologies of wearable/implantable monitoring systems and the 'smart-house' project. This review concludes by discussing future challenges of the future aged society.

  12. Newborn Physiological Immaturity

    PubMed Central

    Fabrellas-Padrés, Núria; Delgado-Hito, Pilar; Hurtado-Pardos, Bárbara; Martí-Cavallé, Montserrat; Gironès-Nogué, Marta; García-Berman, Rosa-Maria; Alonso-Fernandez, Sergio

    2015-01-01

    Background: Most standardized nursing care plans for healthy neonates include multiple nursing diagnoses to reflect nurses' judgments on the infant's status; however scientific literature concerning this issue is scarce. Newborn physiological immaturity is a concept in the ATIC terminology (architecture, terminology, interface, information, nursing [infermeria], and knowledge [coneixement]) to represent the natural status of vulnerability of the healthy neonate. Purpose: To identify the essential attributes of the concept and provide its conceptual and operational definition, using the Wilsonian approach. Findings: The concept under analysis embeds a natural cluster of vulnerabilities and environmental interactions that enhance the evolving maturation process. Implications for Practice: The use of this diagnosis may simplify the process of charting the nursing care plans and reduce time needed for documentation while maintaining the integrity of the information. Implications for Research: Consistent development and use of nursing concepts is essential for knowledge building. Studies on the actual use of nursing diagnoses are needed to inform decision making. PMID:25822514

  13. [Middle ear physiology].

    PubMed

    Ayerbe, I; Négrevergne, M; Ucelay, R; Sanchez Fernandez, J M

    1999-01-01

    The middle ear forms part of the sound transformer mechanism, together with the outer ear and the conducting system of the inner ear. An intermediate sensory organ, sensitive to acoustic vibration, and linked to the inner ear, the middle ear made its appearance during the period of adaptation of marine creatures to a terrestrial habitat; its presence is therefore a phylogenetic requirement. It is classical to ascribe three functions to the middle ear: the transmission of acoustic vibrations from the tympanic membrane to the cochlea, impedance matching between the air in the external auditary meatus and the labyrinthine fluids, and protection of the inner ear by means of the acoustic reflex. If the classical mechanical explanation has been able to explain its function, the conceptualization of its physiology in terms of energy allows an even better understanding, as well as providing and explanation for the paradoxes which arise in clinical practice when the classical model is used.

  14. Prostaglandins in reproductive physiology*

    PubMed Central

    Craig, Gillian M.

    1975-01-01

    The role of prostaglandins in reproductive physiology is reviewed with particular emphasis on their possible importance in ovulation in humans. A possible interaction between gonadal steroids, biogenic amines and prostaglandins at hypothalamic-pituitary level, in relation to the release of luteinizing hormone releasing factor, and LH, is discussed. Anomalies regarding the role of oestrogens in LH release are noted, and it is suggested that high oestrogen levels may release prostaglandins from the uterus and/or centrally in humans, in connection with the mid-cycle LH surge and ovulation. A hypothetical role for prostaglandins in sexual behaviour and premenstrual changes is discussed. The hypotheses open up new areas for clinical research to establish the role of prostaglandins in human endocrinology. The need for measurement of prostaglandin metabolites in blood and urine is emphasized. PMID:1089972

  15. Single Cell Physiology

    NASA Astrophysics Data System (ADS)

    Neveu, Pierre; Sinha, Deepak Kumar; Kettunen, Petronella; Vriz, Sophie; Jullien, Ludovic; Bensimon, David

    The possibility to control at specific times and specific places the activity of biomolecules (enzymes, transcription factors, RNA, hormones, etc.) is opening up new opportunities in the study of physiological processes at the single cell level in a live organism. Most existing gene expression systems allow for tissue specific induction upon feeding the organism with exogenous inducers (e.g., tetracycline). Local genetic control has earlier been achieved by micro-injection of the relevant inducer/repressor molecule, but this is an invasive and possibly traumatic technique. In this chapter, we present the requirements for a noninvasive optical control of the activity of biomolecules and review the recent advances in this new field of research.

  16. Herbicides and plant hormesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide hormesis is commonly observed at sub-toxic doses of herbicides and other phytotoxins. The occurrence and magnitude of this phenomenon is influenced by plant growth stage and physiological status, environmental factors, the endpoint measured, and the timing between treatment and endpoint me...

  17. Plant responses to tropospheric ozone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropospheric ozone is the second most abundant air pollutant and an important component of the global climate change. Over five decades of research on the phytotoxicity of ozone in model plants systems, crop plants and forest trees have provided some insight into the physiological, biochemical and m...

  18. Journal of Gravitational Physiology, Volume 13, No. 1

    NASA Technical Reports Server (NTRS)

    Fuller, Charles A. (Editor); Cogoli, Augusto (Editor); Hargens, Alan R. (Editor); Smith, Arthur H. (Editor)

    2006-01-01

    At the outset, the Journal published one issue in 1994. The first number comprised the Proceedings of the 15th Annual International Gravitational Physiology Meeting, held in Barcelona, Spain in October 1993. The Proceedings of the previous 14 Annual Meetings appeared as supplements to The Physiologist from 1979 to 1993. Each year, one issue of the Journal is devoted to the Annual Meeting Proceedings, and up to four more issues are comprised of full-length research papers. Additionally, Supplement Issues are considered by the Editorial Board as they are submitted. The Journal is published for the International Society for Gravitational Physiology by the Galileo Foundation, a 501(c)(3) nonprofit public benefit corporation. This issue, the first number of 2006, comprises the Proceedings of the joint meeting of the International Society for Gravitational Physiology s 27th Annual International Gravitational Physiology Meeting, held in Osaka, Japan 23- 28 April, 2006. The Journal of Gravitational Physiology invites the submission of original experimental or observational papers on subjects in the field of gravitational physiology. Review articles, theoretical papers and historical or biographical articles will also be solicited by the Editor for publication. The wide scientific span of the Journal rests on physiology as its keystone. Gravitational physiology is considered to include the effects of changes in the magnitude and directions of the gravitational force environment on cells and physiological systems and behavior of humans, animals and plants. The effects of weightlessness during space flight, high sustained G forces and chronic acceleration, vibration, impact and the various forms of simulated weightlessness are also included, as well as is consideration of the evolutionary consequences of gravity and the role of gravity in the manifestation of scale effects in animals and plants.

  19. Optofluidics of plants

    NASA Astrophysics Data System (ADS)

    Psaltis, Demetri; Vasdekis, Andreas E.; Choi, Jae-Woo

    2016-05-01

    Optofluidics is a tool for synthesizing optical systems, making use of the interaction of light with fluids. In this paper we explore optofluidic mechanisms that have evolved in plants where sunlight and fluidic control combine to define most of the functionality of the plan. We hope that the presentation of how plants function, from an optofluidics point of view, will open a window for the optics community to the vast literature of plant physiology and provide inspiration for new ideas for the design of bio-mimetic optofluidic devices.

  20. Procedures of Exercise Physiology Laboratories

    NASA Technical Reports Server (NTRS)

    Bishop, Phillip A.; Fortney, Suzanne; Greenisen, Michael; Siconolfi, Steven F.; Bamman, Marcas M.; Moore, Alan D., Jr.; Squires, William

    1998-01-01

    This manual describes the laboratory methods used to collect flight crew physiological performance data at the Johnson Space Center. The Exercise Countermeasures Project Laboratory is a standard physiology laboratory; only the application to the study of human physiological adaptations to spaceflight is unique. In the absence of any other recently published laboratory manual, this manual should be a useful document staffs and students of other laboratories.

  1. Physiological Monitoring in Diving Mammals

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Physiological Monitoring in Diving Mammals Andreas...large, freely diving whales. We wanted to study physiological responses during diving in free-ranging, deep diving cetaceans. The idea was to measure...contain a sensor to be implanted into the muscle. The logger will collect physiological data from muscle tissue in freely diving marine mammals. The

  2. [Plant hydroponics and its application prospect in medicinal plants study].

    PubMed

    Zeng, Yan; Guo, Lan-Ping; Huang, Lu-Qi; Sun, Yu-Zhang

    2007-03-01

    This article introduced the theorem and method of hydroponics. Some examples of studies in agriculture and forestry were presented, the effects of elements, environmental stress and hormones on physiology of medicinal plants by using hydroponics were analyzed. It also introduced the feasibility and advantage of hydroponics in intermediate propagation and allelopathy of medicinal plant. And finally it made the conclusion that the way of hydroponics would be widely used in medicinal plant study.

  3. Physiology of ice hockey.

    PubMed

    Montgomery, D L

    1988-02-01

    Ice hockey is characterized by high intensity intermittent skating, rapid changes in velocity and duration, and frequent body contact. The typical player performs for 15 to 20 minutes of a 60-minute game. Each shift lasts from 30 to 80 seconds with 4 to 5 minutes of recovery between shifts. The intensity and duration of a particular shift determines the extent of the contribution from aerobic and anaerobic energy systems. The high intensity bursts require the hockey player to develop muscle strength, power, and anaerobic endurance. The length of the game and the need to recover quickly from each shift demands a good aerobic system. Physical characteristics of elite players show that defensemen are taller and heavier than forwards probably due to positional demands. Hockey players are mesomorphic in structure. They are relatively lean since excess mass is detrimental to their skating performance. There is a large interindividual variability in VO2 during skating. Both the aerobic and anaerobic energy systems are important during a hockey game. Peak heart rates during a shift on the ice exceed 90% of HRmax with average on-ice values of about 85% of HRmax. Blood lactate is elevated above resting values confirming the anaerobic nature of the game. Glycogen depletion studies show a preferential utilisation of glycogen from the slow twitch fibres but also significant depletion from the fast twitch fibres. Elite hockey players display a muscle fibre composition similar to untrained individuals. Physiological profiles of elite hockey teams reveal the importance of aerobic endurance, anaerobic power and endurance, muscular strength and skating speed. Training studies have attempted to improve specific components of hockey fitness. Using traditional laboratory tests, a season of hockey play shows gains in anaerobic endurance but no change in aerobic endurance. On-ice tests of hockey fitness have been recommended as an essential part of the hockey player's physiological

  4. Applied physiology of rowing.

    PubMed

    Hagerman, F C

    1984-01-01

    Elite oarsmen and oarswomen possess large body dimensions and show outstanding aerobic and anaerobic qualities. Oarsmen have VO2max values of 6.1 +/- 0.6 L/min and have incurred O2 debts of between 10 and 20 litres. The caloric expenditure of rowing estimated from the O2 cost of a 6-minute rowing ergometer exercise was calculated at 36 kcal/min, one of the highest energy costs so far reported for any predominantly aerobic-type sport. Aerobic and anaerobic calculations show that 70 to 75% of the energy necessary to row the standard 2000m distance for men is derived from aerobiosis while the remaining 25 to 30% is anaerobic. Women achieve VO2max values of 4.1 +/- 0.4 L/min and slightly lower anaerobic values than men. The relative 60 to 65% energy contribution of aerobic metabolism and 35 to 40% for anaerobiosis is not surprising since women compete at 1000m. Rowers also exhibit excellent isokinetic leg strength and power when compared with other elite athletes and oarswomen produced higher relative leg strength values than men when lean body mass is considered. Muscle fibre type distributions in oarsmen resemble those of distance runners while women tend to have a slightly higher proportion of fast-twitch fibres. An average power output of 390 +/- 13.6W was produced by oarsmen for 6 minutes of simulated rowing while women were able to develop 300 +/- 18.4 for 3 minutes of the same activity. Mechanical efficiency for rowing was calculated at 20 +/- 0.9%. Oarsmen also achieve very high ventilation volumes being able to average above 200 L/min BTPS for 6 minutes of simulated rowing; women ventilate 170 L/min BTPS for 3 minutes of this exercise. Excellent VO2/VE and O2 pulse values demonstrate outstanding cardiorespiratory efficiency. Both oarsmen and oarswomen utilise a unique physiological pattern of race pacing; they begin exertion with a vigorous sprint which places excessive demands on anaerobic metabolism followed by a severely high aerobic steady-state and then

  5. Physiology of vitreous surgery.

    PubMed

    Stefánsson, Einar

    2009-02-01

    Vitreous surgery has various physiological and clinical consequences, both beneficial and harmful. Vitrectomy reduces the risk of retinal neovascularization, while increasing the risk of iris neovascularization, reduces macular edema and stimulates cataract formation. These clinical consequences may be understood with the help of classical laws of physics and physiology. The laws of Fick, Stokes-Einstein and Hagen-Poiseuille state that molecular transport by diffusion or convection is inversely related to the viscosity of the medium. When the vitreous gel is replaced with less viscous saline, the transport of all molecules, including oxygen and cytokines, is facilitated. Oxygen transport to ischemic retinal areas is improved, as is clearance of VEGF and other cytokines from these areas, thus reducing edema and neovascularization. At the same time, oxygen is transported faster down a concentration gradient from the anterior to the posterior segment, while VEGF moves in the opposite direction, making the anterior segment less oxygenated and with more VEGF, stimulating iris neovascularization. Silicone oil is the exception that proves the rule: it is more viscous than vitreous humour, re-establishes the transport barrier to oxygen and VEGF, and reduces the risk for iris neovascularization in the vitrectomized-lentectomized eye. Modern vitreous surgery involves a variety of treatment options in addition to vitrectomy itself, such as photocoagulation, anti-VEGF drugs, intravitreal steroids and release of vitreoretinal traction. A full understanding of these treatment modalities allows sensible combination of treatment options. Retinal photocoagulation has repeatedly been shown to improve retinal oxygenation, as does vitrectomy. Oxygen naturally reduces VEGF production and improves retinal hemodynamics. The VEGF-lowering effect of photocoagulation and vitrectomy can be augmented with anti-VEGF drugs and the permeability effect of VEGF reduced with corticosteroids

  6. Brain Physiology: Research and Theory.

    ERIC Educational Resources Information Center

    Esler, William K.

    1982-01-01

    Indicates how research about the physiology and chemistry of the brain verifies the educational applications of Piaget's theory. Discusses maturation, experience, social transmission, and equilibration. (Author/DC)

  7. Physiological responses of dwarf coconut seedlings irrigated with saline water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of salt-tolerant plants is an important alternative to cope with the problem of salinity in semi-arid regions. The dwarf coconut palm (Cocos nucifera L.) has emerged as a salt-tolerant crop once established. However, little is known about the physiological mechanisms that may contribute to t...

  8. Smolt physiology and endocrinology

    USGS Publications Warehouse

    McCormick, Stephen D.; McCormick, Stephen D.; Farrell, Anthony Peter; Brauner, Colin J.

    2013-01-01

    Hormones play a critical role in maintaining body fluid balance in euryhaline fishes during changes in environmental salinity. The neuroendocrine axis senses osmotic and ionic changes, then signals and coordinates tissue-specific responses to regulate water and ion fluxes. Rapid-acting hormones, e.g. angiotensins, cope with immediate challenges by controlling drinking rate and the activity of ion transporters in the gill, gut, and kidney. Slow-acting hormones, e.g. prolactin and growth hormone/insulin-like growth factor-1, reorganize the body for long-term acclimation by altering the abundance of ion transporters and through cell proliferation and differentiation of ionocytes and other osmoregulatory cells. Euryhaline species exist in all groups of fish, including cyclostomes, and cartilaginous and teleost fishes. The diverse strategies for responding to changes in salinity have led to differential regulation and tissue-specific effects of hormones. Combining traditional physiological approaches with genomic, transcriptomic, and proteomic analyses will elucidate the patterns and diversity of the endocrine control of euryhalinity.

  9. Starting physiology: bioelectrogenesis.

    PubMed

    Baptista, Vander

    2015-12-01

    From a Cartesian perspective of rational analysis, the electric potential difference across the cell membrane is one of the fundamental concepts for the study of physiology. Unfortunately, undergraduate students often struggle to understand the genesis of this energy gradient, which makes the teaching activity a hard task for the instructor. The topic of bioelectrogenesis encompasses multidisciplinary concepts, involves several mechanisms, and is a dynamic process, i.e., it never turns off during the lifetime of the cell. Therefore, to improve the transmission and acquisition of knowledge in this field, I present an alternative didactic model. The design of the model assumes that it is possible to build, in a series of sequential steps, an assembly of proteins within the membrane of an isolated cell in a simulated electrophysiology experiment. Initially, no proteins are inserted in the membrane and the cell is at a baseline energy state; the extracellular and intracellular fluids are at thermodynamic equilibrium. Students are guided through a sequence of four steps that add key membrane transport proteins to the model cell. The model is simple at the start and becomes progressively more complex, finally producing transmembrane chemical and electrical gradients. I believe that this didactic approach helps instructors with a more efficient tool for the teaching of the mechanisms of resting membrane potential while helping students avoid common difficulties that may be encountered when learning this topic.

  10. Renal physiology of nocturia.

    PubMed

    Verbalis, Joseph G

    2014-04-01

    Renal function, diurnal fluctuations in arginine vasopressin (AVP) secretion, sex, and advanced age affect urine formation and may contribute to nocturia. Renal effects of AVP are mediated by AVP V2 receptors in the kidney collecting duct. Changes in AVP concentration have the greatest relative effects on urine volume when AVP levels are low; therefore small changes can have a large effect on renal water excretion. AVP is the major regulator of water excretion by the kidneys, and AVP levels have been shown to affect nocturnal voiding. Results of several studies show that patients with nocturia had no significant variation in plasma AVP, whereas patients without nocturia had significant diurnal variation in plasma AVP. The V2 receptor gene is located on the X chromosome, which has important sex-specific consequences. For example, mutations in the V2 gene can cause nephrogenic diabetes insipidus, predominantly in men. Age-related changes in water metabolism are associated with overall body composition, kidney, and brain. Older people generally experience decreased extracellular fluid and plasma volume, which leads to increased adverse consequences from net body water gain or loss. Renal function declines with age, and the ability to concentrate urine and conserve sodium is reduced in the elderly. Thirst perception is also decreased in the elderly, who, compared with younger people, tend to hypersecrete AVP in response to higher plasma osmolality, possibly resulting in hyponatremia. These aspects of renal physiology should be considered when antidiuretic drugs are prescribed for the treatment of nocturia.

  11. Field Guide to Plant Model Systems.

    PubMed

    Chang, Caren; Bowman, John L; Meyerowitz, Elliot M

    2016-10-06

    For the past several decades, advances in plant development, physiology, cell biology, and genetics have relied heavily on the model (or reference) plant Arabidopsis thaliana. Arabidopsis resembles other plants, including crop plants, in many but by no means all respects. Study of Arabidopsis alone provides little information on the evolutionary history of plants, evolutionary differences between species, plants that survive in different environments, or plants that access nutrients and photosynthesize differently. Empowered by the availability of large-scale sequencing and new technologies for investigating gene function, many new plant models are being proposed and studied.

  12. Auxin physiology of the tomato mutant diageotropical

    SciTech Connect

    Daniel, S.G.; Rayle, D.L. ); Cleland, R.E. )

    1989-11-01

    The tomato (Lycopersicon esculentum, Mill.) mutant diageotropica (dgt) exhibits biochemical, physiological, and morphological abnormalities that suggest the mutation may have affected a primary site of auxin perception or action. We have compared two aspects of the auxin physiology of dgt and wild-type (VFN8) seedlings: auxin transport and cellular growth parameters. The rates of basipetal indole-3-acetic acid (IAA) polar transport are identical in hypocotyl sections of the two genotypes, but dgt sections have a slightly greater capacity for IAA transport. 2,3,5-Triiodobenzoic acid and ethylene reduce transport in both mutant and wild-type sections. The kinetics of auxin uptake into VFN8 and dgt sections are nearly identical. These results make it unlikely that an altered IAA efflux carrier or IAA uptake symport are responsible for the pleiotropic effects resulting from the dgt mutation. The lack of auxin-induced cell elongation in dgt plants is not due to insufficient turgor, as the osmotic potential of dgt cell sap is less (more negative) than that of VFN8. An auxin-induced increase in wall extensibility, as measured by the Instron technique, only occurs in the VFN8 plants. These data suggest dgt hypocotyls suffer a defect in the sequence of events culminating in auxin-induced cell wall loosening.

  13. Auxin physiology of the tomato mutant diageotropica

    NASA Technical Reports Server (NTRS)

    Daniel, S. G.; Rayle, D. L.; Cleland, R. E.

    1989-01-01

    The tomato (Lycopersicon esculentum, Mill.) mutant diageotropica (dgt) exhibits biochemical, physiological, and morphological abnormalities that suggest the mutation may have affected a primary site of auxin perception or action. We have compared two aspects of the auxin physiology of dgt and wild-type (VFN8) seedlings: auxin transport and cellular growth parameters. The rates of basipetal indole-3-acetic acid (IAA) polar transport are identical in hypocotyl sections of the two genotypes, but dgt sections have a slightly greater capacity for IAA transport. 2,3,5-Triiodobenzoic acid and ethylene reduce transport in both mutant and wild-type sections. The kinetics of auxin uptake into VFN8 and dgt sections are nearly identical. These results make it unlikely that an altered IAA efflux carrier or IAA uptake symport are responsible for the pleiotropic effects resulting from the dgt mutation. The lack of auxin-induced cell elongation in dgt plants is not due to insufficient turgor, as the osmotic potential of dgt cell sap is less (more negative) than that of VFN8. An auxin-induced increase in wall extensibility, as measured by the Instron technique, only occurs in the VFN8 plants. These data suggest dgt hypocotyls suffer a defect in the sequence of events culminating in auxin-induced cell wall loosening.

  14. Importance of carbon dioxide physiological forcing to future climate change.

    PubMed

    Cao, Long; Bala, Govindasamy; Caldeira, Ken; Nemani, Ramakrishna; Ban-Weiss, George

    2010-05-25

    An increase in atmospheric carbon dioxide (CO(2)) concentration influences climate both directly through its radiative effect (i.e., trapping longwave radiation) and indirectly through its physiological effect (i.e., reducing transpiration of land plants). Here we compare the climate response to radiative and physiological effects of increased CO(2) using the National Center for Atmospheric Research (NCAR) coupled Community Land and Community Atmosphere Model. In response to a doubling of CO(2), the radiative effect of CO(2) causes mean surface air temperature over land to increase by 2.86 +/- 0.02 K (+/- 1 standard error), whereas the physiological effects of CO(2) on land plants alone causes air temperature over land to increase by 0.42 +/- 0.02 K. Combined, these two effects cause a land surface warming of 3.33 +/- 0.03 K. The radiative effect of doubling CO(2) increases global runoff by 5.2 +/- 0.6%, primarily by increasing precipitation over the continents. The physiological effect increases runoff by 8.4 +/- 0.6%, primarily by diminishing evapotranspiration from the continents. Combined, these two effects cause a 14.9 +/- 0.7% increase in runoff. Relative humidity remains roughly constant in response to CO(2)-radiative forcing, whereas relative humidity over land decreases in response to CO(2)-physiological forcing as a result of reduced plant transpiration. Our study points to an emerging consensus that the physiological effects of increasing atmospheric CO(2) on land plants will increase global warming beyond that caused by the radiative effects of CO(2).

  15. Leaf proteome characterization in the context of physiological and morphological changes in response to copper stress in sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper (Cu) is an essential micronutrient required for the growth and development of plants. However, at elevated concentrations in soil, copper is very toxic to plant cells due to its inhibitory effects against many physiological and biochemical processes. In spite of its potential physiological an...

  16. Matrix metalloproteinases in plants: a brief overview.

    PubMed

    Marino, Giada; Funk, Christiane

    2012-05-01

    Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases belonging to the metzincin clan. MMPs have been characterized in detail in mammals, and they have been shown to play key roles in many physiological and pathological processes. Plant MMP-like proteases exist, but relatively few have been characterized. It has been speculated that plant MMPs are involved in remodeling of the plant extracellular matrix during growth, development and stress response. However, the precise functions and physiological substrates in higher plants remain to be determined. In this brief overview, we summarize the current knowledge of MMPs in higher plants and algae.

  17. Assessing prebaccalaureate human physiology courses.

    PubMed

    McCleary, V L

    1998-12-01

    Two surveys were conducted between 1994 and 1996. The purpose of the initial survey was to obtain demographic information about prebaccaulareate human physiology courses. Of the 117 responding physiology departments, 50% offered human physiology at the prebaccalaureate level to 14,185 students during the 1994-1995 academic year. The mean was 245 students per year (+/- 30 SE). Class size was limited by 44% of the respondents. Prebaccaluareate human physiology was offered as a separate course from anatomy by 93% of the departments. Sixty-one percent scheduled the course once a year. The purpose of the second survey was to determine how physiology departments evaluated prebaccalaureate physiology courses and faculty. All responding departments utilized student feedback; 38% of the departments included physiology chair review, 38% peer review, and 9% allied health faculty review. Twenty-eight percent of allied health programs evaluated the course. Results indicated that, whereas a significant number of undergraduate students are enrolled in prebaccaluareate physiology courses annually, those courses appear to lack formal, consistent formative evaluation.

  18. Applied physiology of cycling.

    PubMed

    Faria, I E

    1984-01-01

    Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long

  19. PHYSIOLOGICAL STATUS OF MEN SUBJECTED TO PROLONGED CONFINEMENT.

    DTIC Science & Technology

    STRESS(PHYSIOLOGY), STRESS(PHYSIOLOGY), SPACE SIMULATION CHAMBERS, ELECTROCARDIOGRAPHY, BLOOD PRESSURE, RESPIRATION, CARBON DIOXIDE, OXYGEN, RELAXATION(PHYSIOLOGY), EXERCISE (PHYSIOLOGY), PULSES, TOLERANCES(PHYSIOLOGY).

  20. Physiological correlates of mental workload

    NASA Technical Reports Server (NTRS)

    Zacharias, G. L.

    1980-01-01

    A literature review was conducted to assess the basis of and techniques for physiological assessment of mental workload. The study findings reviewed had shortcomings involving one or more of the following basic problems: (1) physiologic arousal can be easily driven by nonworkload factors, confounding any proposed metric; (2) the profound absence of underlying physiologic models has promulgated a multiplicity of seemingly arbitrary signal processing techniques; (3) the unspecified multidimensional nature of physiological "state" has given rise to a broad spectrum of competing noncommensurate metrics; and (4) the lack of an adequate definition of workload compels physiologic correlations to suffer either from the vagueness of implicit workload measures or from the variance of explicit subjective assessments. Using specific studies as examples, two basic signal processing/data reduction techniques in current use, ti