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1

Adhesive Contact Sweeper  

NASA Technical Reports Server (NTRS)

Adhesive contact sweeper removes hair and particles vacuum cleaner leaves behind, without stirring up dust. Also cleans loose rugs. Sweeper holds commercially available spools of inverted adhesive tape. Suitable for use in environments in which air kept free of dust; optics laboratories, computer rooms, and areas inhabited by people allergic to dust. For carpets, best used in tandem with vacuum cleaner; first pass with vacuum cleaner removes coarse particles, and second pass with sweeper extracts fine particles. This practice extends useful life of adhesive spools.

Patterson, Jonathan D.

1993-01-01

2

PERFORMANCE EVALUATION OF AN IMPROVED STREET SWEEPER  

EPA Science Inventory

The report gives results of an extensive evaluation of the Improved Street Sweeper (ISS) in Bellevue, WA, and in San Diego, CA. The cleaning performance of the ISS was compared with that of broom sweepers and a vacuum sweeper. The ISS cleaned streets better than the other sweeper...

3

Plasma sweeper. [Patents  

DOEpatents

A device is described for coupling RF power (a plasma sweeper) from RF power introducing means to a plasma having a magnetic field associated therewith comprises at least one electrode positioned near the plasma and near the RF power introducing means. Means are described for generating a static electric field at the electrode directed into the plasma and having a component substantially perpendicular to the plasma magnetic field such that a non-zero vector cross-product of the electric and magnetic fields exerts a force on the plasma causing the plasma to drift.

Motley, R.W.; Glanz, J.

1982-10-25

4

PERFORMANCE TESTING OF THE DIPERNA SWEEPER  

EPA Science Inventory

The DiPerna Sweeper, a partial-vacuum oil skimmer, was tested in a two-week test program conducted at the U.S. Environmental Test Tank (OHMSETT) in Leonardo, New Jersey. Forty-three oil recovery tests were run. The object of the program was to establish a range of best performanc...

5

Acute Lung Function Response to Dust in Street Sweepers  

PubMed Central

Background: Sweepers are chronically exposed to dust raised during sweeping. Dust is regarded as the most influential agent and it is perceived as a frequent cause of respiratory system illness and may cause acute and chronic lung function impairment. Aims: The aim of this study was to determine the acute lung function changes in sweepers exposed to dust generated from street sweeping. Material and Methods: This study was conducted in central Karnataka, India, on 25 female sweepers and 25 healthy female control subjects who were comparable in age, height and weight. The pulmonary function test was performed in controls, sweepers before and after sweeping, by using RMS medspiror and results were compared by Student’s unpaired ‘t’ test. Results: The results showed a significant reduction in percent predicted values and mean values of FVC, FEV1, PEFR, FEF25-75% and FEF 200-1200 between sweepers and their matched controls. Pulmonary function after sweeping also showed a significant decrease. Conclusions: On comparing the pulmonary functions of sweepers before and after sweeping, it was concluded that inhalation of dust acutely affected the lung function of sweepers in India and that sweepers were at a risk of developing occupation related lung function impairment. We recommend that the workers should use protective face masks and do wet sweeping instead of dry sweeping during sweeping activity. PMID:24298455

Johncy S., Smilee; G., Dhanyakumar; Samuel T., Vivian; K.T., Ajay; Bondade, Suresh Y.

2013-01-01

6

Nuclear-powered space debris sweeper  

NASA Technical Reports Server (NTRS)

Future spacecraft design will be affected by collisions with man-made debris orbiting the earth. Most of this orbital space debris comes from spent rocket stages. It is projected that the source of future debris will be the result of fragmentation of large objects through hypervelocity collisions. Orbiting spacecraft will have to be protected from hypervelocity debris in orbit. The options are to armor the spacecraft, resulting in increased mass, or actively removing the debris from orbit. An active space debris sweeper is described which will utilize momentum transfer to the debris through laser-induced ablation to alter its orbital parameters to reduce orbital lifetime with eventual entry into the earth's atmosphere where it will burn. The paper describes the concept, estimates the amount of velocity change (Delta V) that can be imparted to an object through laser-induced ablation, and investigates the use of a neutral particle beam for the momentum transfer. The space sweeper concept could also be extended to provide a collision avoidance system for the space station and satellites, or could be used for collision protection during interplanetary travel.

Metzger, John D.; Leclaire, Rene J., Jr.; Howe, Steven D.; Burgin, Karen C.

1989-01-01

7

IMPROVED STREET SWEEPERS FOR CONTROLLING URBAN INHALABLE PARTICULATE MATTER  

EPA Science Inventory

The report gives results of an experimental program to develop design modifications that can be used to improve the ability of municipal street sweepers to remove inhalable dust particles from streets. (Dust emissions from paved roads are a major source of urban inhalable particu...

8

Respiratory morbidity among street sweepers working at Hanumannagar Zone of Nagpur Municipal Corporation, Maharashtra.  

PubMed

Due to the occupational exposure street sweepers are very much vulnerable to develop the chronic diseases of respiratory system. Therefore this study was undertaken to find out the proportion of chronic respiratory morbidity among the street sweepers and the role of various associated risk factors. The study included two groups: study group i.e. street sweepers and comparison group (Class IV workers working in the office buildings). Various risk factors studied were age, sex, socioeconomic status, length of service, smoking habit, type of house, area of residence, cooking fuel and pets. Proportion of chronic respiratory morbidity (chronic bronchitis, asthma and bronchiectasis) was higher (8.1%) among street sweepers compared to comparison group (2.1%), the difference being statistically significant. Unconditional multivariate logistic regression revealed that risk of having chronic respiratory morbidity among street sweepers was 4.24 (95% CI of OR = 1.24 to 14.50) times higher than that in the comparison group and the risk increased significantly with increasing length of service (OR = 1.75, 95 % CI = 1.09 to 2.81). PMID:19189837

Yogesh, Sabde D; Zodpey, Sanjay P

2008-01-01

9

Reconstruction of nuclear charged fragment trajectories from a large gap sweeper magnet  

E-print Network

A new method to reconstruct charged fragment four-momentum vectors from measured trajectories behind an open, large gap, magnetic dispersion element (a sweeper magnet) has been developed. In addition to the position and angle behind the magnet it includes the position measurement in the dispersive direction at the target. The method improves the energy and angle resolution of the reconstruction significantly for experiments with fast rare isotopes, where the beam size at the target position is large.

N. Frank; A. Schiller; D. Bazin; W. A. Peters; M. Thoennessen

2007-08-29

10

Effect of Finite Pulse Length and Laser Frequency Chirp on HGHG and EEHG Seeding  

SciTech Connect

Theoretical studies of high-gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) often start from a simplified model in which the beam is assumed infinitely long and longitudinally uniform and the laser induced energy modulation is perfectly sinusoidal and of infinite duration. In such a model the resulting seed has a spectrum consisting of a collection of delta-functions (of zero width) located at the harmonics of the laser frequency. Being a useful tool for study of the seed bunching amplitudes, such a model cannot be used for realistic analysis the spectral properties of the seed. In this paper we take into account the finite duration of the laser pulse as well as some possible laser phase errors to study their effect on the spectrum of the seed.

Stupakov, G.; /SLAC

2011-11-18

11

Injection seeding of a Q-switched alexandrite laser: Study of frequency stabilization  

NASA Technical Reports Server (NTRS)

AlGaAs diode lasers were used to injection seed a pulsed Q-switched alexandrite laser which produces a narrowband of radiation. Injection seeding is a method for achieving linewidths of less than 500 mega-Hz in the output of the broadband, tunable solid state laser. When the laser was set at a current of 59.8 milli-A and a temperature of 14.04 C, the wavelength was 767.6 nano-m. The Q-switched alexandrite laser was injection seeded and frequency stabilization was studied. The linewidth requirement was met, but the stability requirement was not due to drifting in the feedback voltage. Improvements on injection seeding should focus on increasing the feedback voltage to the laser diode, filtering the laser diode by using temperature controlled narrowband filters, and the use of diamond (SiC) grating placed inside the alexandrite laser's resonator cavity.

Brown, Lamarr A.

1992-01-01

12

Simulating Neutron Interactions in the MoNA-LISA/Sweeper Setup with Geant4  

NASA Astrophysics Data System (ADS)

The sweeper magnet is a superconducting dipole designed to bend charged particles of 4 Tm rigidity 43 degrees at a radius of approximately one meter. In a typical experiment neutron-unbound states are populated in a reaction in front of the magnet and emitted neutrons are subsequently detected with the high-efficiency position sensitive neutron detector arrays, MoNA and LISA. Before the neutrons interact in MoNA or LISA, they have to pass through the walls of the sweeper magnet chamber. A Monte Carlo simulation was written using Geant 4 which included MoNA and LISA, as well as the geometry of the sweeper magnet and the chamber. In a recent experiment LISA was positioned at large angles were the neutrons passed through the sidewalls of the chamber. The impact of the sidewalls on the neutron spectra was explored for neutrons from the decay of 12Li -> 11Li + n produced from 50 MeV/u 14B beams on a beryllium target.

McArthur, Magdalene

2012-10-01

13

Self-seeded single-frequency laser peening method  

DOEpatents

A method of operating a laser to obtain an output pulse having a single wavelength, comprises inducing an intracavity loss into a laser resonator having an amount that prevents oscillation during a time that energy from the pump source is being stored in the gain medium. Gain is built up in the gain medium with energy from the pump source until formation of a single-frequency relaxation oscillation pulse in the resonator. Upon detection of the onset of the relaxation oscillation pulse, the intracavity loss is reduced, such as by Q-switching, so that the built-up gain stored in the gain medium is output from the resonator in the form of an output pulse at a single frequency. An electronically controllable output coupler is controlled to affect output pulse characteristics. The laser acts a master oscillator in a master oscillator power amplifier configuration. The laser is used for laser peening.

Dane, C. Brent (Livermore, CA); Hackel, Lloyd (Livermore, CA); Harris, Fritz B. (Rocklin, CA)

2009-08-11

14

3D imaging of tomato seeds using frequency domain optical coherence tomography  

NASA Astrophysics Data System (ADS)

A fast imaging system that can reveal internal sample structures is important for research and quality controls of seeds. Optical coherence tomography (OCT) is a non-invasive optical imaging technique that can acquire high speed, high resolution depth-resolved images in scattering samples. It has found numerous applications in studying various biological tissues and other materials in vivo. A few studies have reported the use of OCT in studying seed morphology. However, 3D imaging of internal seed structure has not been reported before. In this study, we used a frequency domain OCT system to image tomato seeds. The system has a central wavelength of 844nm with a 46.8 nm FWHM bandwidth. The requirement for depth scan was eliminated by using a Fourier domain implementation. The B-scan imaging speed was limited by the spectroscopic imaging CCD at 52 kHz. The calibrated system has a 6.7?m depth resolution and a 15.4?m lateral resolution. Our results show that major seed structures can be clearly visualized in OCT images.

Fan, Chuanmao; Yao, Gang

2012-05-01

15

High frequency plant regeneration from the mature seeds of Garcinia indica  

Microsoft Academic Search

A high frequency plant regeneration system was developed for the production of high yielding elite clones of Garcinia indica via direct organogenesis. A maximum number of 86.2 shoot buds per explant were induced from the mature seed segments cultured\\u000a on Woody plant medium (WPM) supplemented with 2.0 mg dm?3 N6-benzyladenine and 1 mg dm?3 indole-3-acetic acid. Rooting was achieved on

M. Baskaran; S. Krishnan

2011-01-01

16

High frequency plant regeneration from the mature seeds of Garcinia indica  

Microsoft Academic Search

A high frequency plant regeneration system was developed for the production of high yielding elite clones of Garcinia indica via direct organogenesis. A maximum number of 86.2 shoot buds per explant were induced from the mature seed segments cultured\\u000a on Woody plant medium (WPM) supplemented with 2.0 mg dm?3 N6-benzyladenine and 1 mg dm?3 indole-3-acetic acid. Rooting was achieved on

M. Baskaran; S. Krishnan

17

Plasma sweeper to control the coupling of RF power to a magnetically confined plasma  

DOEpatents

A device for coupling RF power (a plasma sweeper) from a phased waveguide array for introducing RF power to a plasma having a magnetic field associated therewith comprises at least one electrode positioned near the plasma and near the phased waveguide array; and a potential source coupled to the electrode for generating a static electric field at the electrode directed into the plasma and having a component substantially perpendicular to the plasma magnetic field such that a non-zero vector cross-product of the electric and magnetic fields exerts a force on the plasma causing the plasma to drift.

Motley, Robert W. (Princeton, NJ); Glanz, James (Lawrenceville, NJ)

1985-01-01

18

Wavemeter measurements of frequency stability of an injection seeded alexandrite laser for pressure and temperature lidar  

NASA Technical Reports Server (NTRS)

The GSFC pressure-temperature lidar is a differential absorption lidar operating in the oxygen A band absorption region (760 to 770 nm), and utilizes two tunable pulsed alexandrite lasers. For obtaining temperature measurements with an accuracy of less than or = 1 K, it has been determined that the stability of the online laser frequency over a period of time corresponding to a set of measurements, 0.1 to 30 min, has to be better than +/- 0.002/cm. In addition, the requirements on laser spectral bandwidth and spectral purity are less than or = 0.02/cm and greater than or = 99.9 percent, respectively. Injection seeding with a stabilized AlGaAs diode laser was used to achieve the required frequency stability and spectral bandwidth. A high resolution Fizeau wavemeter was employed to determine the frequency stability of the pulsed alexandrite laser and determine its bandwidth, mode structure. We present the results of measurements of the frequency stability and the spectrum of the injection seeded alexandrite laser.

Prasad, C. R.; Schwemmer, G. K.; Korb, C. L.

1992-01-01

19

Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes  

NASA Astrophysics Data System (ADS)

A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunes the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.

Nong, Hanond; Pal, Shovon; Markmann, Sergej; Hekmat, Negar; Mohandas, Reshma A.; Dean, Paul; Li, Lianhe; Linfield, Edmund H.; Giles Davies, A.; Wieck, Andreas D.; Jukam, Nathan

2014-09-01

20

Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes  

SciTech Connect

A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunes the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.

Nong, Hanond, E-mail: Nong.Hanond@rub.de; Markmann, Sergej; Hekmat, Negar; Jukam, Nathan, E-mail: Nathan.Jukam@rub.de [Arbeitsgruppe Terahertz Spektroskopie und Technologie, Ruhr-Universität Bochum, Bochum 44780 (Germany); Pal, Shovon [Arbeitsgruppe Terahertz Spektroskopie und Technologie, Ruhr-Universität Bochum, Bochum 44780 (Germany); Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum 44780 (Germany); Mohandas, Reshma A.; Dean, Paul; Li, Lianhe; Linfield, Edmund H.; Giles Davies, A. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Wieck, Andreas D. [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum 44780 (Germany)

2014-09-15

21

Spectral linewidth preservation in parametric frequency combs seeded by dual pumps.  

PubMed

We demonstrate new technique for generation of programmable-pitch, wideband frequency combs with low phase noise. The comb generation was achieved using cavity-less, multistage mixer driven by two tunable continuous-wave pump seeds. The approach relies on phase-correlated continuous-wave pumps in order to cancel spectral linewidth broadening inherent to parametric comb generation. Parametric combs with over 200-nm bandwidth were obtained and characterized with respect to phase noise scaling to demonstrate linewidth preservation over 100 generated tones. PMID:23038314

Tong, Zhi; Wiberg, Andreas O J; Myslivets, Evgeny; Kuo, Bill P P; Alic, Nikola; Radic, Stojan

2012-07-30

22

Injection seeded single-frequency pulsed Nd:YAG laser resonated by an intracavity phase modulator.  

PubMed

A reliable single frequency Q-switched Nd:YAG laser is developed by using a lithium niobate crystal as the intracavity phase modulator. Successful injection seeding is performed by adopting an electro-optic crystal in an effectively simplified cavity arrangement. The laser is capable of producing 4.8 mJ pulse-energy at 400 Hz repetition rate with nearly Fourier-transform-limited spectral linewidth. The pulse duration is approximately 25 ns, and the beam quality factor M2 is less than 1.3. PMID:25402883

Zhang, Junxuan; Zhu, Xiaolei; Zang, Huaguo; Ma, Xiuhua; Yin, Suyong; Li, Shiguang; Chen, Weibiao

2014-11-01

23

Frequency mixing in accelerator based sources and application to tunable seeded free-electron lasers  

NASA Astrophysics Data System (ADS)

In this article we address the problem of tunability of seeded free-electron lasers (FELs), working typically in the domain of the vacuum ultraviolet. The seeding of FELs with an external laser permits us to obtain FEL pulses with both good longitudinal coherence and good stability properties (contrary to an amplification starting from noise). However, with a fixed external laser wavelength, only amplification at harmonics of this wavelength is possible. If full tunability is wanted, it is necessary to have a tunable external source; but this type of source has much less power, hence it is much harder to reach high harmonics numbers. Here we propose the so-called frequency mixing scheme (from its analogy with the similar process in nonlinear optics), based on two laser/electron interactions. Numerical and analytic studies show that it permits to increase significantly the tunability at short wavelengths using a low-energy tunable source. Numerical simulations are made with the parameters of FERMI-FEL 1, the first seeded FEL for user operation.

Evain, C.; Roussel, E.; Szwaj, C.; Bielawski, S.

2014-12-01

24

Frequency-locked, injection-seeded, pulsed narrowband optical parametric generator.  

PubMed

A frequency-locked, injection-seeded, pulsed optical parametric generator (OPG) has been developed for short-range infrared differential absorption lidar (DIAL) applications. The periodically poled lithium niobate OPG is pumped by a passively Q-switched Nd:YAG microlaser and is seeded by a distributed feedback (DFB) diode laser. The OPG is designed for DIAL measurement of a narrow R-branch transition of methane at 3.2704 microm. The output of the OPG is a two-pulse sequence with a 100-micros temporal separation between the pulses, where the first pulse is absorbed by methane and the second pulse is not absorbed. The first pulse is actively locked to the methane absorption feature by use of the derivative of the transmission spectrum through a reference cell. Although the device was not optimized for output power, the 3.27-microm OPG output energies of the first and second pulses are 5.5 and 5.9 microJ, respectively, producing 21 mW when operated at 1818 Hz. PMID:12833962

Reichardt, Thomas A; Bambha, Ray P; Kulp, Thomas J; Schmitt, Randal L

2003-06-20

25

Calibration of the Sweeper Chamber Charged-Particle Detectors for the LISA Commissioning Experiment  

NASA Astrophysics Data System (ADS)

The new LISA (Large-area multi-Institutional Scintillator Array) neutron detector array, designed to be used in conjunction with MoNA (Modular Neutron Array) was recently commissioned at the NSCL in an experiment designed to investigate excited states of neutron-rich Oxygen isotopes near the neutron drip-line. Charged fragments resulting from the neutron decays were swept out of the beam direction by the Sweeper Magnet after which they passed through a series of charged-particle detectors for fragment trajectory and energy determination. In order to achieve isotope separation and identification at the focal plane, which is then used to reconstruct the invariant mass of the unbound states, precise determinations of the fragment and neutron energies and trajectories are required. To correct for time-drifts in the charge-particle detectors that develop over the entire length of the experiment, Root C++ macros were developed to analyze and precisely correct for these detector drifts to within few tenths of a nanosecond. Root macros were also developed to position calibrate the ion chamber and CRDC's. Results for the LISA commissioning run will be presented.

Kwiatkowski, J.; Grovom, A.; Rogers, W.

2011-10-01

26

Online/offline injection seeding system with high frequency-stability and low crosstalk for water vapor DIAL  

NASA Astrophysics Data System (ADS)

A compact and rugged distributed feedback (DFB) laser system has been developed as online-offline injection seeder for the laser transmitter of a ground-based water vapor differential absorption lidar (WV DIAL) near 820 nm. The frequency stability of this injection seeder system shows a standard deviation of only 6.3 MHz and a linewidth of less than 4.6 MHz during continuous operation of more than 14 h. These values by far exceed the requirements for WV DIAL. By use of a novel technique based on an electro-optic deflector (EOD), alternating online-offline wavelength switching is achieved for each shot of the seeded laser with 250 Hz with a response time of less than 10 ?s and very low crosstalk between the channels of only 33 dB. As a result, a spectral purity of 99.95% is reached by the WV DIAL transmitter which again fulfills the requirements for WV DIAL measurements with high accuracy. Because moveable parts are not present in the seeding system, this setup is significantly less sensitive to acoustic vibrations and ambient temperature drifts during field experiments than other seeding systems which use external cavity diode lasers (ECDL) and mechanical switches. By our new seeding system not only the requirements for ground-based water-vapor DIAL are met but also for space-borne WV DIAL applications that pose even higher demands to the frequency stability and spectral purity of the laser transmitters.

Späth, Florian; Metzendorf, Simon; Behrendt, Andreas; Wizemann, Hans-Dieter; Wagner, Gerd; Wulfmeyer, Volker

2013-11-01

27

High-frequency mechanical stirring initiates anisotropic growth of seeds requisite for synthesis of asymmetric metallic nanoparticles like silver nanorods.  

PubMed

High-speed stirring at elevated temperatures is shown to be effective in the symmetry-breaking process needed for the growth of the hard-to-synthesize silver nanorods from the polyol reduction of silver ions. This process competes with the facile formation of more symmetrical, spherical and cubic, nanoparticles. Once the seed is formed, further growth proceeds predominantly along the long axis, with a consequent increase of the particles' aspect ratio (that of the nanorod). When stirring is stopped shortly after seed formation, nanorods with a broad distribution of aspect ratios are obtained, while when the high-frequency stirring continues the distribution narrows significantly. The width of the nanorods can only be increased if the initial concentration of Ag(+) ions increases. Reducing the stirring speeds during seed formation lowers the yield of nanorods. Molecular dynamics simulations reveal that the formation of a nanometer-scale thin boundary region between a solid facet of the nanoparticle and the liquid around it, and the accommodation processes of metal (Ag) atoms transported through this boundary region from the liquid to the solid growth interface, are frustrated by sufficiently fast shear flow caused by high-frequency stirring. This arrests growth on seed facets parallel to the flow, leading, together with the preferential binding of the capping polymer to the (100) facet, to the observed growth in the (110) direction, resulting in silver nanorods capped at the ends by (111) facets and exposing (100) facets on the side walls. PMID:24053557

Mahmoud, Mahmoud A; El-Sayed, Mostafa A; Gao, Jianping; Landman, Uzi

2013-10-01

28

H{sup -} beam extraction from a cesium seeded field effect transistor based radio frequency negative hydrogen ion source  

SciTech Connect

H{sup -} beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10{sup 19} m{sup -3} was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H{sup -} ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents.

Ando, A.; Matsuno, T.; Funaoi, T.; Tanaka, N. [School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)

2012-02-15

29

H- beam extraction from a cesium seeded field effect transistor based radio frequency negative hydrogen ion source.  

PubMed

H(-) beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10(19) m(-3) was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H(-) ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents. PMID:22380279

Ando, A; Matsuno, T; Funaoi, T; Tanaka, N; Tsumori, K; Takeiri, Y

2012-02-01

30

High power single frequency 780nm laser source generated from frequency doubling of a seeded fiber amplifier in a cascade of PPLN crystals.  

PubMed

We report on the generation of over 900 mW of tunable cw light at 780 nm by single pass frequency doubling of a high power fiber amplifier in a cascade of two periodically poled Lithium Niobate (PPLN) crystals. Over 500 mW is generated in the first crystal. In the limit of low pump power, we observe an efficiency of 4.6 mW/W2-cm for a single crystal, and 5.6 mW/W2-cm for a combination of two crystals, with an enhancement of the doubling efficiency observed with two crystals due to the presence of second harmonic light from the first crystal acting as a seed for the second. We have frequency locked this laser source relative to a rubidium D2 hyperfine line and demonstrated its utility in a sophisticated laser cooling apparatus. PMID:19466050

Thompson, R; Tu, M; Aveline, D; Lundblad, N; Maleki, L

2003-07-14

31

Development of narrow-linewidth Yb- and Er- fiber lasers and frequency mixing for ArF excimer laser seeding  

NASA Astrophysics Data System (ADS)

We propose and report a 193 nm narrow-linewidth light generation by a frequency mixing of Yb and Er-fiber lasers as the seed for an ArF excimer laser. The Yb-fiber laser includes a pulsed distributed feedback (DFB) or external cavity diode laser (ECDL), acousto-optic modulator(AOM), fiber amplifiers and an Yb:YAG single crystal fiber (SCF) power amplifier with more than 7 W output. The Er-fiber laser consists of a continuous-wave (CW) DFB laser, a semiconductor optical amplifier (SOA), and fiber amplifiers. The second harmonic generation (SHG) and the fourth harmonic generation (FHG) of Yb laser at 515 nm and 258 nm reach 5 W and 1.5 W, respectively. Two stages of sum-frequency generation (SFG) produce the power of 100 mW for 193 nm laser by use of CLBO crystals.

Xuan, Hongwen; Zhao, Zhigang; Igarashi, Hironori; Ito, Shinji; Kakizaki, Kouji; Kobayashi, Yohei

2014-03-01

32

Frequency stabilization and transverse mode discrimination in injection-seeded unstable resonator TEA CO2 lasers  

NASA Technical Reports Server (NTRS)

Longitudinal mode selection by injection has been demonstrated as a viable technique for TEA-CO2 lasers with pulse energies of a Joule or greater. Once reliable generation of single-longitudinal-mode (SLM) pulses is obtained, the characteristics and the causes of intrapulse frequency variation can be studied. These include the effect of the decaying plasma, the thermal gradient due to the energy dissipation associated with the laser mechanism itself, and the pressure shift of the center frequency of the laser transition. The use of the positive-branch unstable resonator as an efficient means of coupling a discharge with large spatial dimensions to an optical cavity mode introduces another concern: namely, what can be done to emphasize transverse mode discrimination in an unstable resonator cavity while maintaining high coupling efficiency. These issues are discussed in this paper, and relevant experimental results are included.

Ancellet, G. M.; Menzies, R. T.; Brothers, A. M.

1987-01-01

33

USD-FH: Jamming-resistant wireless communication using Frequency Hopping with Uncoordinated Seed Disclosure  

Microsoft Academic Search

Spread spectrum techniques (e.g., Frequency Hopping (FH), Direct Sequence Spread Spectrum (DSSS)) have been widely used for anti-jamming wireless communications. Such techniques require that communicating devices agree on a shared secret before communication. However, it is non-trivial for two devices that do not share any secret to establish one in presence of a jammer. Recently, several schemes relying on Uncoordinated

An Liu; Peng Ning; Huaiyu Dai; Yao Liu

2010-01-01

34

A shrunken-2 Transgene Increases Maize Yield by Acting in Maternal Tissues to Increase the Frequency of Seed Development[W  

PubMed Central

The maize (Zea mays) shrunken-2 (Sh2) gene encodes the large subunit of the rate-limiting starch biosynthetic enzyme, ADP-glucose pyrophosphorylase. Expression of a transgenic form of the enzyme with enhanced heat stability and reduced phosphate inhibition increased maize yield up to 64%. The extent of the yield increase is dependent on temperatures during the first 4 d post pollination, and yield is increased if average daily high temperatures exceed 33°C. As found in wheat (Triticum aestivum) and rice (Oryza sativa), this transgene increases maize yield by increasing seed number. This result was surprising, since an entire series of historic observations at the whole-plant, enzyme, gene, and physiological levels pointed to Sh2 playing an important role only in the endosperm. Here, we present several lines of evidence that lead to the conclusion that the Sh2 transgene functions in maternal tissue to increase seed number and, in turn, yield. Furthermore, the transgene does not increase ovary number; rather, it increases the probability that a seed will develop. Surprisingly, the number of fully developed seeds is only ?50% of the number of ovaries in wild-type maize. This suggests that increasing the frequency of seed development is a feasible agricultural target, especially under conditions of elevated temperatures. PMID:22751213

Hannah, L. Curtis; Futch, Brandon; Bing, James; Shaw, Janine R.; Boehlein, Susan; Stewart, Jon D.; Beiriger, Robert; Georgelis, Nikolaos; Greene, Thomas

2012-01-01

35

Multiline short-pulse solid-state seeded carbon dioxide laser for extreme ultraviolet employing multipass radio frequency excited slab amplifier.  

PubMed

In this Letter we describe in more detail a solid-state seeded, nanosecond pulse, multiline CO(2) oscillator designed and built for the extreme ultraviolet (EUV) laser-produced-plasma (LPP) source. Our oscillator featured quantum cascade laser seeders, a diffraction-type seed beam combiner, and a radio-frequency-discharge-excited, diffusion-cooled, slab-waveguide CO(2) gain cell in a compact multipass regenerative amplifier configuration. The oscillator generated pulses of exceptional stability in terms of envelope, energy, and spectrum. Excellent stability of output was achieved without any additional techniques. The output spectrum consisted of two laser lines of a 00(0)1-10(0)0 band of a CO(2) molecule, P20 and P22, with a target of four lines P18-P24. The pulse duration was electronically adjustable between 11 and 35 ns at a repetition frequency from a few hertz to hundreds of kilohertz. Electronic adjustment of the pulse duration was achieved by relative timing offsets of individual seeders, opening an avenue to a range of on-line adjustments of pulse shape and spectral content timing. The jitter-tolerant operation allows for easy synchronization with an external event, such as a droplet target in an EUV LPP source. A resistance to parasitic seeding of more than 40 dB was recorded. The oscillator produced up to 20 W of average output power at a repetition rate of 100 kHz in a near-diffraction-limited beam of M(2)<1.3 and a pointing stability below 50 ?rad. PMID:23503247

Nowak, Krzysztof M; Ohta, Takeshi; Suganuma, Takashi; Fujimoto, Junichi; Mizoguchi, Hakaru

2013-03-15

36

Alien dandelion reduces the seed-set of a native congener through frequency-dependent and one-sided effects  

Microsoft Academic Search

In conservation biology, increasing numbers of studies have focused on reproductive interference (RI) between a native species\\u000a and related aliens. However, few studies have examined the frequency dependence of RI, despite of its key importance to invasiveness.\\u000a Here, we report for the first time frequency-dependent RI in a pair of native and alien dandelions: Taraxacum japonicum and T. officinale, respectively.

Koh-Ichi Takakura; Takayoshi Nishida; Takashi Matsumoto; Sachiko Nishida

2009-01-01

37

Transverse-flow radio-frequency-excited amplifier seeded by a cavity-dumped CO2 laser for an extreme ultraviolet light source.  

PubMed

A transverse-flow radio-frequency-exited CO2 laser amplifier was evaluated by a short-pulse seed laser. We constructed a prototype transverse-flow amplifier for the extreme UV laser-produced-plasma source. The electrical power for the discharge was enhanced to 100 kW at a 100% duty cycle. A Q-switched cavity-dumped CO2 seed laser emitting 13 ns pulses with a repetition rate of 100 kHz was amplified along a fivefold optical path in the amplifier gain medium. As a result, the amplifier output an average power of 3.07 kW with an 8.5 W laser input. The electrical-to-optical efficiency was 3.1%, which was far higher than that of axial-flow amplifiers at the same laser input power. The pulse showed a slight stretch from an input duration of 13 ns to an output of 15 ns. PMID:23988937

Tanino, Yoichi; Nishimae, Junichi; Yamamoto, Tatsuya; Funaoka, Koji; Tamida, Taichiro; Tsuda, Shingo; Fujikawa, Shuichi

2013-09-01

38

Influence of optical filters on pulse circulation in fiber rings with a frequency shifter and EDFA.  

PubMed

Optical fiber ring circuits constructed with frequency shifters and EDFAs are applicable to pulsed lightwave frequency sweepers, wavelength converters, and optical packet buffers. The salient criterion for those applications is how many times the optical pulse can circle the ring. Optical band-pass filters in the ring can serve an important role for pulse circulation because the filter determines the gain bandwidth at every circulation under the condition of signal wavelength shift. This paper clarifies the effects of optical filter response on pulse circulation in the ring through numerical simulation of the EDFA dynamic model, considering the gain spectrum. PMID:19529428

Takano, Katsumi; Nakagawa, Kiyoshi; Ito, Hiromasa

2006-10-30

39

Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser  

NASA Astrophysics Data System (ADS)

We present a cylindrically curved GaAs x-ray spectrometer with energy resolution ?E/E = 1.1 × 10-4 and wave-number resolution of ?k/k = 3 × 10-3, allowing plasmon scattering at the resolution limits of the Linac Coherent Light Source (LCLS) x-ray free-electron laser. It spans scattering wavenumbers of 3.6 to 5.2/Å in 100 separate bins, with only 0.34% wavenumber blurring. The dispersion of 0.418 eV/13.5 ?m agrees with predictions within 1.3%. The reflection homogeneity over the entire wavenumber range was measured and used to normalize the amplitude of scattering spectra. The proposed spectrometer is superior to a mosaic highly annealed pyrolytic graphite spectrometer when the energy resolution needs to be comparable to the LCLS seeded bandwidth of 1 eV and a significant range of wavenumbers must be covered in one exposure.

Zastrau, Ulf; Fletcher, Luke B.; Förster, Eckhart; Galtier, Eric Ch.; Gamboa, Eliseo; Glenzer, Siegfried H.; Heimann, Philipp; Marschner, Heike; Nagler, Bob; Schropp, Andreas; Wehrhan, Ortrud; Lee, Hae Ja

2014-09-01

40

Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser  

E-print Network

We present a cylindrically curved GaAs x-ray spectrometer with energy resolution $\\Delta E/E = 1.1\\cdot 10^{-4}$ and wave-number resolution of $\\Delta k/k = 3\\cdot 10^{-3}$, allowing plasmon scattering at the resolution limits of the Linac Coherent Light Source (LCLS) x-ray free-electron laser. It spans scattering wavenumbers of 3.6 to $5.2/$\\AA\\ in 100 separate bins, with only 0.34\\% wavenumber blurring. The dispersion of 0.418~eV/$13.5\\,\\mu$m agrees with predictions within 1.3\\%. The reflection homogeneity over the entire wavenumber range was measured and used to normalize the amplitude of scattering spectra. The proposed spectrometer is superior to a mosaic HAPG spectrometer when the energy resolution needs to be comparable to the LCLS seeded bandwidth of 1~eV and a significant range of wavenumbers must be covered in one exposure.

Zastrau, Ulf; Foerster, Eckhart; Galtier, Eric Ch; Gamboa, Eliseo; Glenzer, Siegfried H; Heimann, Philipp; Marschner, Heike; Nagler, Bob; Schropp, Andreas; Wehrhan, Ortrud; Lee, Hae Ja

2014-01-01

41

A further discussion of the factors controlling the distribution of Pt, Pd, Rh and Au in road dust, gullies, road sweeper and gully flusher sediment in the city of Sheffield, UK.  

PubMed

Forty paired road dust and gully sediments from the city of Sheffield in NE England show that high platinum, palladium and rhodium concentrations derived from catalytic converters depend on proximity to both roundabouts rather than traffic lights and to topographic lows. Road dust outside schools and control samples, further away on the same road, show that Pt, Pd and Rh concentrations are dependent on passing traffic flow rather than numbers of stopping vehicles. Highest values of Pt+Pd in road dust are 852 ppb and 694 ppb in gullies. Rh has maximum values of 113 ppb in road dust and 49 ppb in gullies. Pt and Pd values of a few ppb to just over 100 ppb occur in road dust where traffic does not stop, on roads away from junctions. Pt, Pd, Rh and Au are all picked up by road sweepers and gully flushers both with maximum values of just over 100 ppb Pt and Pd. High Au values (maximum 610 ppb in a road dust) were located on pavements, in suburbs, outside schools and in road sweepers collecting in residential areas rather than on high traffic flow roads. Stratification of Pt and Pd in gullies was not observed whereas a high Au value was recorded at the bottom of a gully suggesting gravity concentration for Au. Anomalous Pd grades of 1050 ppb in road dust from a school entrance and 2040 ppb in a street sweeper sample were recorded. These high Pd- and Au-bearing samples do not have anomalous Pt or Rh values and may be sourced from jewellery or dental fillings. However, most samples have consistent Pt/Pd ratios of about 1 and Pt/Rh values of 4 to 5 indicating a catalytic converter source. Pt and Pd are concentrated in road dust at levels well above background in all the samples, including on high and low traffic flow roads. PMID:19081605

Prichard, H M; Sampson, J; Jackson, M

2009-02-15

42

A cost-effective fast frequency-hopped code-division multiple-access light source using self-seeded fabry-Pe´rot laser with fiber Bragg grating array  

Microsoft Academic Search

We propose a novel light source for the optical fast frequency-hopped code-division multiple-access scheme using a self-seeded gain-switched Fabry-Pe´rot laser diode (FP-LD) with the reconfigurable fiber Bragg grating array (FBGA). The embedded FBGA in the external cavity loop encodes the input pulses both temporally and spectrally. Before feeding back into the FP-LD, the encoded optical pulses propagate the FBGA with

Wei-Ren Peng; Peng-Chun Peng; Wen-Piao Lin; Kuei-Chu Hsu; Yin-Chieh Lai; Sien Chi

2004-01-01

43

Novel methods of analyzing radio-frequency echo signals for the purpose of imaging brachytherapy seeds used to treat prostate cancer  

NASA Astrophysics Data System (ADS)

Brachytherapy using small implanted radioactive seeds is becoming an increasingly popular method for treating prostate cancer. Seeds are inserted into the prostate transperineally using ultrasound guidance. Dosimetry software determines the optimal placement of seeds for achieving the prescribed dose based on ultrasonic determination of the gland boundaries. However, because of prostate movement after planning images are acquired and during the implantation procedure, seeds commonly are not placed in the desired locations and the delivered dose may differ from the prescribed dose. Current methods of ultrasonic imaging do not adequately display implanted seeds for the purpose of correcting the delivered dose. We are investigating new methods of ultrasonic imaging that overcome limitations of conventional ultrasound. These methods include resonance, modified elastographic, and signature techniques. Each method shows promise for enhancing the visibility of seeds in ultrasound images. Combining the information provided by each method may reduce ambiguities in determining where seeds are present or absent. If successful, these novel imaging methods will enable correction of seed-misplacement errors during the implantation procedure, and hence will improve the therapeutic radiation dose delivered to target tissues.

Feleppa, Ernest J.; Ramachandran, Sarayu; Alam, Sheikh K.; Kalisz, Andrew; Ketterling, J. A.; Ennis, Ronald D.; Wuu, Cheng-Shie

2002-04-01

44

Seeding Rangeland  

E-print Network

Most Texas rangeland produces below its potential. Improving rangeland requires brush control and/or seeding to restore production to the site's potential. This publication is a guide to seeding rangelands, and discusses when, where, how, and what...

Welch, Tommy G.; Hafercamp, Marshall R.

2001-01-04

45

Seed Size  

NSDL National Science Digital Library

In this activity, learners collect, arrange, and draw various seeds from smallest to biggest. They also estimate how many of the smallest would fit into the biggest. In addition, learners predict how many seeds they would find inside an apple or lemon, and cut open these fruits to check their prediction against the real seed count. The Did You Know section describes the biggest and smallest seeds on Earth.

Science, Lawrence H.

2007-01-01

46

Seed proteomics  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seeds comprise a protective covering, a small embryonic plant, and a nutrient-storage organ. Seeds are protein-rich, and have been the subject of many mass spectrometry-based analyses. Seed storage proteins (SSP), which are transient depots for reduced nitrogen, have been studied for decades by cel...

47

Designer Seeds  

NSDL National Science Digital Library

In this activity students examine a variety of seeds, describe them, and determine how they are dispersed. Students investigate seed dispersal mechanisms. Students, working in pairs, create and test a wind dispersed seed that they have designed themselves. Students are limited to using a single piece of white paper, one lima bean to represent a seed, tape and scissors. Seeds are tested by dropping them in front of a window fan and recording the distance they travel. Repeat trials are conducted, averages calculated, and class data recorded. Students examine the features of successful seeds and redesign their seed to try to increase the distance it can be carried by wind. Results are analyzed and comparisons made to natural phenomena.

BEGIN:VCARD VERSION:2.1 FN:Frank Taylor N:Taylor;Frank ORG:Radford High School REV:2005-04-09 END:VCARD

1995-06-30

48

Analysis of the plasma sweeper  

SciTech Connect

The coupling of lower hybrid waves to a plasma can be modified by placing potentials on electrodes near the mouth of a phased array. Positive potentials on the electrodes create an electric field that sweeps the plasma away at a velocity c anti E x anti B/B/sup 2/. In this paper we derive the electric field created by the applied potential from the nondivergent character of the current flow and the ion momentum equation, in which ion-neutral charge-exchange collisions are retained, and we compare the predictions with experimental data.

Glanz, J.; Motley, R.W.

1982-09-01

49

J. Range Manage. Switchgrass recruitment from broadcast seed vs.  

E-print Network

to that of broadcast seed in terms of establishment (frequency of occurrence and density), plant growth and final plant, establishmentand growth Key Words: (Panicum virgatum L.), seed dispersal, revegeta- tion/restoration, plant sire. The frequency of plots with emerging switchgrassplants ranged from 62to 100% when seeds were

Archer, Steven R.

50

Seed proteomics.  

PubMed

Seeds comprise a protective covering, a small embryonic plant, and a nutrient-storage organ. Seeds are protein-rich, and have been the subject of many mass spectrometry-based analyses. Seed storage proteins (SSP), which are transient depots for reduced nitrogen, have been studied for decades by cell biologists, and many of the complicated aspects of their processing, assembly, and compartmentation are now well understood. Unfortunately, the abundance and complexity of the SSP requires that they be avoided or removed prior to gel-based analysis of non-SSP. While much of the extant data from MS-based proteomic analysis of seeds is descriptive, it has nevertheless provided a preliminary metabolic picture explaining much of their biology. Contemporary studies are moving more toward analysis of protein interactions and posttranslational modifications, and functions of metabolic networks. Many aspects of the biology of seeds make then an attractive platform for heterologous protein expression. Herein we present a broad review of the results from the proteomic studies of seeds, and speculate on a potential future research directions. PMID:21172463

Miernyk, Ján A; Hajduch, Martin

2011-04-01

51

Verticillium dahliae race 2-specific PCR reveals a high frequency of race 2 strains in commercial spinach seed lots and delineates race structure.  

PubMed

Two pathogenic races of Verticillium dahliae have been described on lettuce and tomato. Host resistance to race 1 is governed by plant immune receptors that recognize the race 1-specific fungal effector Ave1. Only partial resistance to race 2 exists in lettuce. Although polymerase chain reaction (PCR) assays are available to identify race 1, no complementary test exists to positively identify race 2, except for lengthy pathogenicity assays on host differentials. Using the genome sequences of two isolates of V. dahliae, one each from races 1 and 2, we identified potential markers and PCR primers to distinguish the two races. Several primer pairs based on polymorphisms between the races were designed and tested on reference isolates of known race. One primer pair, VdR2F-VdR2R, consistently yielded a 256-bp amplicon in all race 2 isolates exclusively. We screened DNA from 677 V. dahliae isolates, including 340 from spinach seedlots, with the above primer pair and a previously published race 1-specific primer pair. DNA from isolates that did not amplify with race 1-specific PCRs amplified with the race 2-specific primers. To validate this, two differential lines of lettuce were inoculated with 53 arbitrarily selected isolates from spinach seed and their pathogenicity and virulence were assessed in a greenhouse. The reactions of the differential cultivars strongly supported the PCR data. V. dahliae race structure was investigated in crops in coastal California and elsewhere using primers specific to the two races. All artichoke isolates from California were race 1, whereas nearly all tomato isolates were race 2. Isolates from lettuce, pepper, and strawberry from California as well as isolates from spinach seed from two of four countries comprised both races, whereas only race 2 was observed in cotton, mint, olive, and potato. This highlights the importance of identifying resistance against race 2 in different hosts. The technique developed in this study will benefit studies in ecology, population biology, disease surveillance, and epidemiology at local and global scales, and resistance breeding against race 2 in lettuce and other crops. PMID:24502204

Short, Dylan P G; Gurung, Suraj; Maruthachalam, Karunakaran; Atallah, Zahi K; Subbarao, Krishna V

2014-07-01

52

Watermelon Seed Germination  

E-print Network

Watermelon Seed Germination Purdue University Cooperative Extension Service BP-62 Seed Germination of the necessary genetic material or chromosomes. These seed, known as triploid, have special germination requirements. This bulletin addresses triploid watermelon seed germination and transplant production. First

53

Big Seed  

NSDL National Science Digital Library

This free iOS app helps develop spatial reasoning and strategic thinking. Users reflect seed squares (horizontally, vertically and diagonally) to grow larger pieces that eventually cover the given design space without spilling over. A graduated set of difficulty levels makes the game accessible to a wide range of ages.

2012-12-06

54

Seed Treatment. Bulletin 760.  

ERIC Educational Resources Information Center

This manual gives a definition of seed treatment, the types of seeds normally treated, diseases and insects commonly associated with seeds, fungicides and insecticides used, types of equipment used for seed treatment, and information on labeling and coloring of treated seed, pesticide carriers, binders, stickers, and safety precautions. (BB)

Lowery, Harvey C.

55

Seed Treatment. Manual 92.  

ERIC Educational Resources Information Center

This training manual provides information needed to meet minimum EPA standards for certification as a commercial applicator of pesticides in the seed treatment category. The text discusses pests commonly associated with seeds; seed treatment pesticides; labels; chemicals and seed treatment equipment; requirements of federal and state seed laws;…

Missouri Univ., Columbia. Agricultural Experiment Station.

56

How Seeds Travel  

NSDL National Science Digital Library

Students will rotate around to 7 different stations to identify how the 7 presented seeds travel, whether it be by wind, water, or animal. They will then record it in their plant journals by illustrating the seed, listing its characteristics, and identifying the way in which it travels. Designer Seeds 7 Stations Coconut-Water Maple Seed- Wind Burdock (burrs) - Animals ...

Liston, Mrs

2009-11-09

57

Vegetable Seed Saving Handbook  

NSDL National Science Digital Library

This Vegetable Seed Saving Handbook online is a great resource for anyone wanting to harvest viable Fast Plants seeds to plant right away (as in selection experiments) or save for future use. Follow the instructions for cabbage family seeds (Brassica raps, in particular). If you're planning on saving your seeds, treat Fast Plants seeds as "desiccation-tolerant" as described here: http://howtosaveseeds.com/store.php

58

The effects of endophytes on seed production and seed predation of tall fescue and meadow fescue.  

PubMed

Fungal endophytes of grasses are often included in agricultural management and in ecological studies of natural grass populations. In European agriculture and ecological studies, however, grass endophytes are largely ignored. In this study, we determined endophyte infection frequencies of 13 European cultivars and 49 wild tall fescue (Schedonorus phoenix) populations in Northern Europe. We then examined seed production and seed predation of endophyte-infected (E+) and endophyte-free (E-) tall fescue (in wild grass populations and in a field experiment) and meadow fescue (Schedonorus pratensis; in a field experiment only). Endophytes were detected in only one of the 13 cultivars. In contrast, >90% of wild tall fescue plants harbored endophytes in 45 wild populations but were absent in three inland populations in Estonia. In three wild tall fescue study sites, 17%, 22%, and 56% of the seeds were preyed upon by the cocksfoot moth. Endophyte infection did not affect seed mass of tall fescue in the field experiment. However, seed predation was lower in E+ than E- grasses in the two tall fescue populations with higher predation rates. For meadow fescue, the mean number of seeds from E+ plants was higher than E- plants, but E- and E+ seeds had equal rates of predation by the moth. Our results suggest that the effects of grass endophytes on seed production and cocksfoot moth seed predation vary considerably among grass species, and the effects may depend on herbivore pressure and other environmental conditions. PMID:20871988

Saari, Susanna; Helander, Marjo; Faeth, Stanley H; Saikkonen, Kari

2010-11-01

59

The Seed Biology Place  

NSDL National Science Digital Library

This remarkable site was created by Professor Gerhard Leubner and his colleagues at the University of Freiburg in Germany. Here, visitors can take advantage of a veritable cornucopia of reference materials related to seed biology, such as diagrams and illustrations of seed germination, plant hormones, endosperm weakening, and seed dormancy. Neophytes may wish to start by looking at the Seed Structure and Anatomy area, which features a concise and well-written overview of the structure, anatomy, and morphology of mature seeds. The same section contains information on the seed structure of the castor bean and other legumes. Another fascinating section on the site is dedicated to Seed Evolution. Visitors can discover a wealth of information here, including such topics as the evolutionary trends of angiosperm seeds and the seed ferns of the Late Permian period. All told, the site is a wonderful resource, and visitors will want to share it with friends.

Leubner, Gerhard

2012-02-10

60

Photoacoustic Study of Fungal Disease of Acai ( Euterpe oleracea) Seeds  

Microsoft Academic Search

Photoacoustic spectroscopy is introduced as a promising experimental technique to investigate fungus infected Acai ( Euterpe oleracea) seeds. Photoacoustic spectra of healthy and infected Acai seeds with the fungus Colletotrichum gloeosporioides were recorded firstly in the modulation frequency range of 5Hz to 700 Hz, while keeping the wavelength of excitation radiation of a Xe arc-lamp constant, to ascertain the depth

Denise V. Rezende; O. A. C. Nunes; A. C. Oliveira

2009-01-01

61

Evaluating Cotton Seed Quality  

E-print Network

, treated and bagged for planting the following season. Producers who plan to save seed from conventional varieties are advised to evaluatr seed quality before the planting season, using procedures such as the free fatty acid test, germination tests...

Boman, Randy

2005-10-05

62

Seeds as allelopathic agents  

Microsoft Academic Search

Inhibitors of germination or of growth, highly diversified chemicals are commonly found in higher plants. They occur in vegetative organs as well as in seeds or other dispersal units. Nonprotein amino acids, when present, are mainly found in seeds where they can occur in extremely high concentrations. Density of seeds, rate of emanation of inhibitors, their amount and effectiveness, all

Jacob Friedman; George R. Waller

1983-01-01

63

Seeds to crystals  

Microsoft Academic Search

Seeding has been critical for obtaining diffraction-quality crystals for many structures. In this article, applications and recommendations for seeding are presented based on examples from our laboratory and other groups. The implementation of seeding in high-throughput crystallization, robotics, and other emerging technologies is also discussed.

Terese Bergfors

2003-01-01

64

Alfalfa Seed Testing.  

E-print Network

SALSOLA KAU TRAGUS. CUSCUTA ARVE -. direction of Dr Ball -L. CI t ..-A - . All seeds shoy nx+gn!fied. 15 time ALFALFA SEED TESTING. 5 that the "hump" lies generally near the middle of the concave side. The seed gradually loses its lustre with age... ............................. ....................... : I- . Dodder, Cuscuta Epithy- ... 1 ....................... .............................. mum. - -- pp - - - -- .................... ........ r, ........... I-,: : : N: : : : : , Lambs Quarter, Chenopodi...

Ball, O. M. (Oscar Melville)

1905-01-01

65

Going to Seed.  

ERIC Educational Resources Information Center

Describes a unit on seeds designed to introduce students to their scientific and nutritional uses. Unit activities are easily done, employ a variety of process skills, and can be used at various grade levels. Suggests field trips to gather seeds, seed sprouting, and making cookies out of various whole grains. (JM)

Powell, Richard R.

1984-01-01

66

SEED Database Requirements  

Microsoft Academic Search

SEED is an acronym for Software Environment to Support the Early Phases in Building Design. The overall architecture of SEED is based on a division of the preliminary design process into phases, each of which addresses a specific task. SEED intends to support each phase by an individual support module based on a shared logic and architecture. The modules envisioned

Robert Coyne; Robert Woodbury; Shang-Chia Chiou; Bongjin Choi; Han Kiliccote; Teng-Weng Chang; Sheng-Fen Chien; Jim Snyder

67

Preservation of recalcitrant seeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Recalcitrant and intermediate seeds are not included in seed banks because of misperceptions that these efforts would be futile. Between 20 and 25% of the Earth’s angiosperm species are estimated to produce recalcitrant or intermediate seeds. These species are more prevalent in the tropics and sub...

68

Seed Development and Germination  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seed is the fertilized and matured ovule of angiosperms and gymnosperms and represents a crucial stage in the life cycle of plants. Seeds of diverse plant species may display differences in size, shape and color. Despite apparent morphological variations, most mature seeds consist of three major com...

69

A scalable multipass laser cavity based on injection by frequency conversion for noncollective Thomson scatteringa...  

E-print Network

isolator. A type 2 potassium dihydrogen phosphate KDP crystal frequency doubles the seed beam to 532 nm is shown in Fig. 1. The cell is seeded with the University of California, Los Angeles PHOENIX Nd:glass laser, a 1064 nm, 40 mm beam that provides 20 J in 5 ns. The seed laser is frequency doubled inside

California at Los Angles, University of

70

Patterns of movement and seed dispersal by three lemur species.  

PubMed

We combined data on gut-passage times, feeding, and movement to explore the patterns of seed dispersal by Eulemur rubriventer, Eulemur rufrifrons, and Varecia variegata editorum lemurs in Ranomafana National Park, Madagascar. These lemur species deposited less than half of their consumed seeds >100?m away from conspecific trees (40-50%). Long-distance dispersal (>500?m) was rare and average dispersal distances were short relative to those reported of similar-sized haplorrhine primates. The three lemur species showed no significant differences in mean seed-dispersal distances. However, they differed in the shape of their frequency distributions of seed-dispersal distances as a result of differences in how they moved through their habitats. The short distances of seed dispersal we observed and the depauperate frugivorous fauna in Madagascar suggest seed-dispersal may be more limited than in other tropical forests with important implications for plant-community dynamics, biodiversity maintenance, and restoration efforts in Madagascar. PMID:24038313

Razafindratsima, Onja H; Jones, Thomas A; Dunham, Amy E

2014-01-01

71

Control of Weeds at a Pinyon-Juniper Site by Seeding Grasses  

Microsoft Academic Search

An area seeded to perennial grasses and an adjacent nonseeded area both within a burned Colorado pinyon\\/Utahjuniper (Pinus edulis Engelm.\\/Juniperus osteosperma (Torr.) Little) com­ munity provided an opportunity to contrast frequency of plant species in the two treatments. Lower frequencies for cheatgrass (Bromus tectorum L.) and yellow salsify (Tragopogon dubius Scop.), which are introduced annuals, were found in the seeded

Sherel Goodrich; Dustin Rooks

72

Seed Dispersal 101  

NSDL National Science Digital Library

This two-minute radio program introduces listeners to the variety of agents that disperse seeds. The program's guest, a plant biologist, cites examples of nonliving and living dispersal agents that include the wind, water, and such animals as birds and bats. He also explains that a plant's fruits or seeds often offer clues about how they are dispersed. The program, which is available here in audio and text, is the first in a series about seed dispersal. Copyright 2005 Eisenhower National Clearinghouse

Planet, Pulse O.

2007-07-26

73

The effect of burial depth on removal of seeds of Phytolacca americana.  

SciTech Connect

Abstract - Although burial is known to have important effects on seed predation in a variety of habitats, the role of burial depth in affecting the removal of seeds in early successional systems is poorly known. Phytolacca American (pokeweed) is a model species to examine the role of burial depth in affecting seed removal because it is common in early-successional habitats, studies suggest that seed removal is indicative of seed predation, and seed predation is related to the recruitment of mature plants. To determine how burial depth affects P. americana seed removal, 20 seeds of P. americana were buried at depths of 0, 1, or 3 cm in early-successional habitats at the Savannah River Site in South Carolina for over 6 weeks. The frequency with which seeds were encountered (as measured by the removal of at least one seed) and the proportion of seeds removed was significantly greater when seeds were on the soil surface (0 cm depth) compared to seeds that were buried 1 cm or 3 cm; there was no difference in encounter or removal between seeds at 1 cm or 3 cm. Our findings suggest that burial may have important consequences for P. americana population dynamics, because seed survival depends upon whether or not the seed is buried, and relatively shallow burial can yield large increases in seed survival. Because seed limitation is known to be an important determinant of plant community composition in early successional systems, our work suggests that burial may play an unappreciated role in the dynamics of these communities by reducing predator-mediated seed limitation.

Orrock, John, L.: Damschen, Ellen, I.

2007-04-01

74

RF sensing of grain and seed moisture content  

Microsoft Academic Search

A brief review is presented on the electrical prop- erties of cereal grains and their use in sensing moisture content of grain and seed. The basic principles are described for using radio-frequency (RF) (including high frequencies and microwaves) dielectric properties, or permittivity, of grain for sensing moisture through their correlation with moisture content. The development of density-independent functions of the

Stuart O. Nelson; Samir Trabelsi; Andrzej W. Kraszewski

2001-01-01

75

SEEDS AND VARIETIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seed is one of the most important factors in sugarbeet production. Without a uniform plant population of a sugarbeet variety adapted to the growing region, the producer will have difficulty achieving economical crop production. Seed selection will be one of the most important decisions a grower wi...

76

I. Buried seed populations  

Microsoft Academic Search

Numbers of buried legume seeds in the upper layers of soil were determined in a survey over an area of hill country pasture at the Grasslands Division research station, Ballantrae. Seeds of suckling clover (Trifolium dubium L.) and white clover (T. repens L.) were most numerous, mean numbers per m being average for this particular type of pasture (2541 and

J. F. L. Charlton

1977-01-01

77

GROWING SEEDS, TEACHER'S GUIDE.  

ERIC Educational Resources Information Center

THIS TEACHER'S GUIDE IS DESIGNED FOR USE WITH AN ELEMENTARY SCIENCE STUDY UNIT, "GROWING SEEDS," IN WHICH SUCH BASIC SCIENCE SKILLS AND PROCESSES AS MEASUREMENT, OBSERVATION, AND HYPOTHESIS FORMATION ARE INTRODUCED THROUGH STUDENT ACTIVITIES INVOLVING SEEDS, GERMINATION, AND SEEDLING GROWTH. THE MATERIALS WERE DEVELOPED FOR USE IN ELEMENTARY…

Elementary Science Study, Newton, MA.

78

When Seed Dispersal Matters  

NSDL National Science Digital Library

This peer-reviewed resource from Bioscience journal is about the varying importance of seed dispersal within plant communities. A profusion of fruit forms implies that seed dispersal plays a central role in plant ecology, yet the chance that an individual seed will ultimately produce a reproductive adult is low to infinitesimal. Extremely high variance in survival implies that variations in fruit production or transitions from seed to seedling will contribute little to population growth. The key issue is that variance in survival of plant life-history stages, and therefore the importance of dispersal, differs greatly among and within plant communities. In stable communities of a few species of long-lived plants, variances in seed and seedling survival are immense, so seed-to-seedling transitions have little influence on overall population dynamics. However, when seedlings in different circumstances have very different chances of survival--in ecological succession, for example, or when dispersed seeds escape density-dependent mortality near parent trees--the biased survival of dispersed seeds or seedlings in some places rather than others results in pervasive demographic impacts.

HENRY F. HOWE and MARIA N. MIRITI (; )

2004-07-01

79

Millennium Seed Bank Project  

NSDL National Science Digital Library

A number of organizations have developed a concerted interest in establishing seed banks to protect the wide diversity of existing plant life for future generations. The Royal Botanic Gardens is currently working on their own project, whose ultimate goal is to collect 24,000 plant species. So far, they have successfully secured samples from almost all of the native flowering plants in the United Kingdom, and their work continues on in the present day. Many visitors to the site will want to peruse their homepage and the helpful graphic (a peapod) helps orient first-time visitors to the various sections on the site, such as "Solving Seed Problems" and their publications and data area. The site also includes a field manual for those who would like to collect their own seeds in the field as well as data about the seeds collected thus far in the Seed Information Database.

2005-01-01

80

Seed germination and vigor.  

PubMed

Germination vigor is driven by the ability of the plant embryo, embedded within the seed, to resume its metabolic activity in a coordinated and sequential manner. Studies using "-omics" approaches support the finding that a main contributor of seed germination success is the quality of the messenger RNAs stored during embryo maturation on the mother plant. In addition, proteostasis and DNA integrity play a major role in the germination phenotype. Because of its pivotal role in cell metabolism and its close relationships with hormone signaling pathways regulating seed germination, the sulfur amino acid metabolism pathway represents a key biochemical determinant of the commitment of the seed to initiate its development toward germination. This review highlights that germination vigor depends on multiple biochemical and molecular variables. Their characterization is expected to deliver new markers of seed quality that can be used in breeding programs and/or in biotechnological approaches to improve crop yields. PMID:22136565

Rajjou, Loïc; Duval, Manuel; Gallardo, Karine; Catusse, Julie; Bally, Julia; Job, Claudette; Job, Dominique

2012-01-01

81

Soybean seed proteome rebalancing  

PubMed Central

The soybean seed’s protein content and composition are regulated by both genetics and physiology. Overt seed protein content is specified by the genotype’s genetic framework and is selectable as a breeding trait. Within the genotype-specified protein content phenotype soybeans have the capacity to rebalance protein composition to create differing proteomes. Soybeans possess a relatively standardized proteome, but mutation or targeted engineering can induce large-scale proteome rebalancing. Proteome rebalancing shows that the output traits of seed content and composition result from two major types of regulation: genotype and post-transcriptional control of the proteome composition. Understanding the underlying mechanisms that specifies the seed proteome can enable engineering new phenotypes for the production of a high-quality plant protein source for food, feed, and industrial proteins. PMID:25232359

Herman, Eliot M.

2014-01-01

82

Defoliation effects on Bromus tectorum seed production: Implications for grazing  

USGS Publications Warehouse

Cheatgrass (Bromus tectorum L.) is an invasive annual grass that creates near-homogenous stands in areas throughout the Intermountain sagebrush steppe and challenges successful native plant restoration in these areas. A clipping experiment carried out at two cheatgrass-dominated sites in eastern Oregon (Lincoln Bench and Succor Creek) evaluated defoliation as a potential control method for cheatgrass and a seeding preparation method for native plant reseeding projects. Treatments involved clipping plants at two heights (tall = 7.6 cm, and short = 2.5 cm), two phenological stages (boot and purple), and two frequencies (once and twice), although purple-stage treatments were clipped only once. Treatments at each site were replicated in a randomized complete block design that included a control with no defoliation. End-of-season seed density (seeds??m-2) was estimated by sampling viable seeds from plants, litter, and soil of each treatment. Undipped control plants produced an average of approximately 13 000 and 20 000 seeds??m-2 at Lincoln Bench and Succor Creek, respectively. Plants clipped short at the boot stage and again 2 wk later had among the lowest mean seed densities at both sites, and were considered the most successful treatments (Lincoln Bench: F 6,45 = 47.07, P < 0.0001; Succor Creek: F6,40 = 19.60, P < 0.0001). The 95% confidence intervals for seed densities were 123-324 seeds??m-2 from the Lincoln Bench treatment, and 769-2256 seeds??m-2 from the Succor Creek treatment. Literature suggests a maximum acceptable cheatgrass seed density of approximately 330 seeds??m-2 for successful native plant restoration through reseeding. Thus, although this study helped pinpoint optimal defoliation parameters for cheatgrass control, it also called into question the potential for livestock grazing to be an effective seed-bed preparation technique in native plant reseeding projects in cheatgrass-dominated areas.

Hempy-Mayer, K.; Pyke, D.A.

2008-01-01

83

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2010 CFR

... 3 2010-01-01 2010-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2010-01-01

84

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2012 CFR

... 3 2012-01-01 2012-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2012-01-01

85

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2014 CFR

... 3 2014-01-01 2014-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2014-01-01

86

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2013 CFR

... 3 2013-01-01 2013-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2013-01-01

87

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2011 CFR

... 3 2011-01-01 2011-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2011-01-01

88

Magnetic stimulation of marigold seed  

NASA Astrophysics Data System (ADS)

The effects of magnetic field treatments of French marigold seeds on germination, early seedling growth and biochemical changes of seedlings were studied under controlled conditions. For this purpose, seeds were exposed to five different magnetic seed treatments for 3 min each. Most of seed treatments resulted in improved germination speed and spread, root and shoot length, seed soluble sugars and a-amylase activity. Magnetic seed treatment with 100 mT maximally improved germination, seedling vigour and starch metabolism as compared to control and other seed treatments. In emergence experiment, higher emergence percentage (4-fold), emergence index (5-fold) and vigorous seedling growth were obtained in seeds treated with 100 mT. Overall, the enhancement of marigold seeds by magnetic seed treatment with 100 mT could be related to enhanced starch metabolism. The results suggest that magnetic field treatments of French marigold seeds have the potential to enhance germination, early growth and biochemical parameters of seedlings.

Afzal, I.; Mukhtar, K.; Qasim, M.; Basra, S. M. A.; Shahid, M.; Haq, Z.

2012-10-01

89

Investigation of the effect of space flight factors on chromosomes in seeds  

NASA Technical Reports Server (NTRS)

Frequency of mutations in postflight air-dry Crepis capillaris seeds, kept for five days aboard an artificial satellite was 36.0 + or - 1.9%, vs. 19.01 + or - 1.2% for seeds in a similar ground experiment. Both groups of seeds were prepared in identical concentrations and were treated by the same mutagen. The spectrum of mutations in postflight Crepis capillaris seeds contained a large number of chromosome-type mutations and some cells showed multiple alterations. Postflight seeds not treated with mutagens had a slightly higher level of mutability.

Dubinina, L. G.

1980-01-01

90

Genetically Modified Food Seeds: Genetically Modified Food Seeds: Genetically Modified Food Seeds: Genetically Modified Food Seeds: Genetically Modified Food Seeds: Health, Socioeconomic  

Microsoft Academic Search

Although concerns about genetically modified (GM) food seeds are serious and well-founded, the problems which these seeds raise are usually not unique to GM seeds alone. GM organisms are only one example of problematic new varieties or breeds. Large soybean and other monocultural plantations have serious environmental effects which GM seeds exacerbate. Although GM seeds may benefit large scale commercial

Frank J. Leavitt

91

Photoacoustic Study of Fungal Disease of Acai ( Euterpe oleracea ) Seeds  

Microsoft Academic Search

Photoacoustic spectroscopy is introduced as a promising experimental technique to investigate fungus infected Acai (Euterpe oleracea) seeds. Photoacoustic spectra of healthy and infected Acai seeds with the fungus Colletotrichum gloeosporioides were recorded firstly in the modulation frequency range of 5Hz to 700 Hz, while keeping the wavelength of excitation radiation\\u000a of a Xe arc-lamp constant, to ascertain the depth of penetration

Denise V. Rezende; O. A. C. Nunes; A. C. Oliveira

2009-01-01

92

Seed Dispersal: Lemurs  

NSDL National Science Digital Library

Trees in Madagascar's forests have evolved traits that promote the dispersal of their seeds by lemurs. This two-minute radio program focuses on the interaction between forest plants and lemurs--the main seed dispersers in the forests. A guest scientist explains why lemurs ingest seeds that are large relative to their body size. He also notes that the fruits of Madagascar's trees have evolved to be strong smelling but drably colored in accordance with lemurs' keen sense of smell and poor vision. The program is available in text and audio formats. The latter includes audio of ring-tailed lemurs. Copyright 2005 Eisenhower National Clearinghouse

Pulse of the Planet

2007-09-20

93

Cactus seed germination: a review  

Microsoft Academic Search

The present review tries to give a general overview of the available information on cactus seed germination. First, information about the family Cactaceae is discussed, concerning aspects such as distribution and general characteristics. Seed distinctive features are mentioned, such as colour, form, and size. Aspects of seed physiology, such as germination and dormancy, as well as seed dynamics including dispersal,

Mariana Rojas-Aréchiga; Carlos Vázquez-Yanes

2000-01-01

94

Fishing for Seeds.  

ERIC Educational Resources Information Center

Describes a method to collect seeds that are dispersed from weeds while avoiding some outdoor hazards such as rough terrain or animals. Describes a plan for creating a weed fishing pole and includes a materials list. (SAH)

Science and Children, 2001

2001-01-01

95

Easy PEAsy Seed Germination  

NSDL National Science Digital Library

In this activity, learners determine the necessary conditions for pea seed germination. This activity encourages learners to make predictions and think about how they might investigate the effects of variables like light, temperature, and moisture.

2012-04-09

96

Tomato seeds for LDEF  

NASA Technical Reports Server (NTRS)

Tomato seeds are prepared for their launch aboard the Langley's Long Duration Exposure Facility. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 119), by James Schultz.

1983-01-01

97

Seed weight variation of Wyoming sagebrush in northern Nevada.  

PubMed

Seed size is a crucial plant trait that may potentially affect not only immediate seedling success but also the subsequent generation. We examined variation in seed weight of Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young), an excellent candidate species for rangeland restoration. The working hypothesis was that a major fraction of spatial and temporal variability in seed size (weight) of Wyoming sagebrush could be explained by variations in mean monthly temperatures and precipitation. Seed collection was conducted at Battle Mountain and Eden Valley sites in northern Nevada, USA, during November of 2002 and 2003. Frequency distributions of seed weight varied from leptokurtic to platykurtic, and from symmetry to skewness to the right for both sites and years. Mean seed weight varied by a factor of 1.4 between locations and years. Mean seed weight was greater (P < 0.05) in 2003 than in 2002 at both sites. This can partially be attributed to 55% greater precipitation in 2003 than 2002, since mean monthly temperatures were similar (P > 0.05) in all study situations. Simple linear regression showed that monthly precipitation (March to November) explained 85% of the total variation in mean seed weight (P = 0.079). Since the relationship between mean monthly temperature (June-November) and mean seed weight was not significant (r2 = 0.00, P = 0.431), this emphasizes the importance of precipitation as an important determinant of mean seed weight. Our results suggest that the precipitation regime to which the mother plant is exposed can have a significant effect on sizes of seeds produced. Hence, seasonal changes in water availability would tend to alter size distributions of produced offspring. PMID:16524249

Busso, Carlos A; Perryman, Barry L

2005-12-01

98

Seeds Of Hope  

Microsoft Academic Search

Seeds of Hope, written for nay (Middle Eastern flute), oud (Middle Eastern lute), and western orchestra, is an attempt at synthesizing two different musical traditions into a single cohesive work. The musical traditions that are consciously synthesized in Seeds of Hope are western classical and popular Arabic music, which is based on the Maqam system.\\u000aMaqam (plural Maqamat) is widely

Doron Kima

2011-01-01

99

QUALITY SEED: SEED IMPROVEMENT, CULTIVAR AND HEALTHY SEED LOT SELECTION, AND THE CERTIFICATION PROCESS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter on seed certification and selecting healthy seed lots is included in Potato Health Management, 2nd edition, an APS series manual. It includes outlines of the certification process including inspections, testing and tagging seed. Certified seed class terminology is explained. It also ...

100

Seed Transmission of Pseudoperonospora cubensis  

PubMed Central

Pseudoperonospora cubensis, an obligate biotrophic oomycete causing devastating foliar disease in species of the Cucurbitaceae family, was never reported in seeds or transmitted by seeds. We now show that P. cubensis occurs in fruits and seeds of downy mildew-infected plants but not in fruits or seeds of healthy plants. About 6.7% of the fruits collected during 2012–2014 have developed downy mildew when homogenized and inoculated onto detached leaves and 0.9% of the seeds collected developed downy mildew when grown to the seedling stage. This is the first report showing that P. cubensis has become seed-transmitted in cucurbits. Species-specific PCR assays showed that P. cubensis occurs in ovaries, fruit seed cavity and seed embryos of cucurbits. We propose that international trade of fruits or seeds of cucurbits might be associated with the recent global change in the population structure of P. cubensis. PMID:25329308

Cohen, Yigal; Rubin, Avia E.; Galperin, Mariana; Ploch, Sebastian; Runge, Fabian; Thines, Marco

2014-01-01

101

Fast-switching system for injection seeding of a high-power Ti:sapphire laser.  

PubMed

A high frequency switching and tunable seed laser system has been designed and constructed for injection seeding of a high-power pulsed Ti:sapphire laser. The whole laser system operates as the transmitter of a scanning, ground-based, water-vapor differential absorption lidar (DIAL). The output of two seed lasers can be tuned in the wavelength range of 815-840 nm up to the power of 20 mW and switched between the online and offline wavelengths of the DIAL at frequencies of 0-1 kHz. The frequency stability of online and offline seed lasers is better than +/-20 MHz rms and the mode-hop-free tuning range is greater than 40 GHz with external cavity diode lasers. The advantage of this system for efficient injection seeding of the Ti:sapphire cavity is that it is modular, robust, fully fiber-coupled, and polarization maintaining. PMID:19655946

Khalesifard, Hamid R; Fix, Andreas; Ehret, Gerhard; Schiller, Max; Wulfmeyer, Volker

2009-07-01

102

Seeding rate and seed size as management techniques for ryegrass (Lolium Multiflorum, Lam) in winter wheat  

E-print Network

Higher seeding rates and larger seed sizes could enhance the competitiveness of wheat with ryegrass. Growth room and field research evaluated the effects of wheat seeding rates and seed size in competition with Italian ryegrass. Winter wheat seeds...

Cook, Casey Lee

2005-08-29

103

An integrated injection seeded THz source and amplifier for time-domain spectroscopy  

E-print Network

An integrated injection seeded THz source and amplifier for time-domain spectroscopy J. Maysonnave, XXXX A terahertz (THz) frequency quantum cascade laser (QCL) is used as an integrated injection seeded source and amplifier for use in THz time-domain spectroscopy. A THz input pulse is generated inside a QCL

Paris-Sud XI, Université de

104

Effects of Rice Seed Surface Sterilization with Hypochlorite on Inoculated Burkholderia vietnamiensis  

Microsoft Academic Search

organism Burkholderia vietnamiensis TVV75. This artifact could not be eliminated simply by rinsing the seeds, even thoroughly, with sterile distilled water. When growth resumed, a significant increase in the frequency of rifampin- and nalidixic acid-resistant mutants in the population was observed compared to the control without seeds. This phenomenon was a specific effect of hypochlorite; it was not observed with

L. Miche; JACQUES BALANDREAU

2001-01-01

105

7 CFR 201.57 - Hard seeds.  

Code of Federal Regulations, 2012 CFR

...SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration...counted as “hard seed.” If at the end of the germination period provided...the percentage of germination. For flatpea, continue the swollen seed in test for 14...

2012-01-01

106

7 CFR 201.57 - Hard seeds.  

Code of Federal Regulations, 2013 CFR

...SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration...counted as “hard seed.” If at the end of the germination period provided...the percentage of germination. For flatpea, continue the swollen seed in test for 14...

2013-01-01

107

7 CFR 201.57 - Hard seeds.  

Code of Federal Regulations, 2011 CFR

...SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration...counted as “hard seed.” If at the end of the germination period provided...the percentage of germination. For flatpea, continue the swollen seed in test for 14...

2011-01-01

108

7 CFR 201.57 - Hard seeds.  

Code of Federal Regulations, 2014 CFR

...SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration...counted as “hard seed.” If at the end of the germination period provided...the percentage of germination. For flatpea, continue the swollen seed in test for 14...

2014-01-01

109

Landscape Corridors Provide Pathway for Seed Dispersal  

NSF Publications Database

... Pathway for Seed Dispersal Birds help habitats maintain diversity Seeds were more often found in ... seeds that came from plants in the central patches. The results were clear: on average, seeds in ...

110

Chia seed oil  

Microsoft Academic Search

Summary  The results of the determination of the chemical composition of chia seed oil are furnished below. The composition of two\\u000a samples of linseed oil determined by Kaufmann and Keller9 is given for comparison.\\u000a \\u000a \\u000a \\u000a The chia seed oil contains a very small amount of oleic glyceride—much less than linseed oil, practically the same amount\\u000a of linolenic glyceride as the Calcutta linseed

WALTER F. BAUGItMAN; George S. Jamieson

1929-01-01

111

Healthy food trends -- chia seeds  

MedlinePLUS

... compared to other oils, even flax seed (linseed) oil . Researchers are looking at whether consuming more of the fatty acids found in chia seeds can improve blood pressure, heart health, blood sugar, or provide ...

112

Lignins of Rumex acetosa Seeds  

Microsoft Academic Search

Spinach seeds were analyzed quantitatively. Wilstetter lignin was isolated and characterized by alkaline hydrolysis of spinach seed-lignocarbohydrate complex. Its elemental composition and molecular weight were determined. Its IR spectrum was analyzed.

G. N. Dalimova; D. N. Dalimov; M. K. Bkhatt

2004-01-01

113

Physical Properties of Guar Seeds  

Microsoft Academic Search

A study on the guar seeds (Cyamopsis tetragonoloba) was performed to investigate the effect of moisture content on the selected physical properties. Moisture contents of seeds\\u000a were varied from 5.2% to 25.0%, dry basis (d.b.). Seed geometric parameters, such as average length, width, thickness, geometric-mean\\u000a diameter, surface area, volume, increased but sphericity decreased with increase in moisture content. The 1,000-seed

Rajesh Kumar Vishwakarma; Uma Shanker Shivhare; Saroj Kumar Nanda

114

Seeds of the world : Journey to Forever  

NSDL National Science Digital Library

Seeds of the world: Journey to Forever - No seeds, no food, vanishing seeds, most crop varieties already lost, rendezvous with extinction, seed saving, biodiversity, world hunger This site discusses the importance of seeds to humans and the global economy. It provides extension information about genetically modified seeds and the Green Revolution.

Keith Addison

2001-01-01

115

NUTRITIVE COMPONENTS IN AUTOTETRAPLOID BUCKWHEAT SEED  

Microsoft Academic Search

The nutritive components of tetraploid buckwheat seed obtained from a traditional diploid variety (KATAOKA) were determined in com­ parison with those of diploid seed. Tetraploid seed was larger than diploid seed, by 14-25% in size and 50% in weight. The protein con­ tent of tetraploid seed was 16% and a little more than that of di­ ploid seed. The difference

Takanori KUSANO; Hiroko CHIUE; Kiyokazu IKEDA; Motoko ARIHARA; Akio UJIHARA

116

Laser seeding for biomolecular crystallization  

Microsoft Academic Search

Crystal seeding, which permits the decoupling of crystal nucleation and growth, is a potentially powerful tool for biomolecular crystallization. However, its usefulness is severely limited by the inability of current techniques to manipulate single seeds and it is often considered as a last resort in protein crystal growth trials. Remarkably, current practice relies on the cumbersome technique of entraining seed

Peter A Bancel; Victoria B Cajipe; Francis Rodier; Jean Witz

1998-01-01

117

Chemometric investigation of mustard seed  

Microsoft Academic Search

Levels of the 11 major glucosinolates and two other characteristics (thousand seed weight and colour) were determined in samples of the mustard seed (of Sinapis alba, Brassica nigra and Brassica juncea) and in samples of the seed of similar Brassica plants (Sinapis arvensis and Brassica napus) available from the local testing stations, the local producers and suppliers. The aim of

J. Velíšek; R. Mikulcová; K. Míková; K. B. Woldie; J. Link; J. Davídek

1995-01-01

118

Seeds: A Celebration of Science.  

ERIC Educational Resources Information Center

The Space Exposed Experiment Developed for Students (SEEDS) Project offered science classes at the 5-12 and college levels the opportunity to conduct experiments involving tomato seeds that had been space-exposed over long periods of time. SEEDS kits were complete packages obtained from the National Aeronautics and Space Administration (NASA) for…

Melton, Bob

119

Reduced seed germination in Arabidopsis over-expressing SWI/SNF2 ATPase genes.  

PubMed

In the life of flowering plants, seed germination is a critical step to ensure survival into the next generation. Generally the seed prior to germination has been in a dormant state with a low rate of metabolism. In the transition from a dormant seed to a germinating seed, various epigenetic mechanisms play a regulatory role. Here, we demonstrate that the over-expression of chromatin remodeling ATPase genes (AtCHR12 or AtCHR23) reduced the frequency of seed germination in Arabidopsis thaliana up to 30% relative to the wild-type seeds. On the other hand, single loss-of-function mutations of the two genes did not affect seed germination. The reduction of germination in over-expressing mutants was more pronounced in stress conditions (salt or high temperature), showing the impact of the environment. Reduced germinations upon over-expression coincided with increased transcript levels of seed maturation genes and with reduced degradation of their mRNAs stored in dry seeds. Our results indicate that repression of AtCHR12/23 gene expression in germinating wild-type Arabidopsis seeds is required for full germination. This establishes a functional link between chromatin modifiers and regulatory networks towards seed maturation and germination. PMID:24839909

Leeggangers, Hendrika A C F; Folta, Adam; Muras, Aleksandra; Nap, Jan-Peter; Mlynarova, Ludmila

2015-02-01

120

Effect of mango weevil (Coleoptera: Curculionidae) damage on mango seed viability in Hawaii.  

PubMed

The mango weevil, Cryptorhynchus (= Sternochetus) mangiferae (F.), is a federally quarantined pest that prevents shipment of mangos from Hawaii into the continental United States. Although this monophagous weevil allegedly causes reduced seed germination, damage to the fruit pulp, and premature fruit drop in mangos, there are few studies examining these potential sources of crop loss. We conducted studies to assess the effect of mango weevil infestation on seed viability while making observations on the frequency of pulp feeding. Naturally infested seeds from mature fruit were planted in pots and scored for successful germination. Germination rates for infested seeds were equal to those of uninfested control seeds in a polyembryonic cultivar ('Common'), whereas germination was significantly reduced for infested seeds of a monoembryonic cultivar ('Haden') compared with uninfested control seeds but germination of infested seeds was still > 70%. To assess seed tolerance of damage, seeds were artificially damaged by cutting away 25, 50, or 75% of the cotyledon before planting and scored for germination. None of the damage treatments was significantly different from the undamaged controls, indicating that mango seeds can withstand substantial damage and still germinate successfully. Over the 2-yr period we conducted experiments, only four of 3,602 mango fruits (0.11%) showed evidence of direct feeding damage to the pulp. Results suggest that C. mangiferae is a less serious pest of mangos than previously thought. PMID:10985036

Follett, P A; Gabbard, Z

2000-08-01

121

The Seeds of Change.  

ERIC Educational Resources Information Center

Discusses "Seeds of Change," a Columbian quincentenary exhibition at the Smithsonian Institution. Describes the rapid transformation of the Americas after contact with the Europeans. Reports that the exhibit explores the destruction of the native population by disease, war, slavery, the ongoing decimation of the rain forest, and the transformation…

Viola, Herman J.

1991-01-01

122

Grass and grain seeds  

NSDL National Science Digital Library

Many types of grasses grow back after they have been cut back or mowed. Some weeds also do this, but other kinds of weeds stop growing once cut. Grains are seeds, but they are also valuable sources of food for humans and animals.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-03

123

SEED Software Annotations.  

ERIC Educational Resources Information Center

This document provides a composite index of the first five sets of software annotations produced by Project SEED. The software has been indexed by title, subject area, and grade level, and it covers sets of annotations distributed in September 1986, April 1987, September 1987, November 1987, and February 1988. The date column in the index…

Bethke, Dee; And Others

124

Seed dormancy and germination  

Microsoft Academic Search

Seed dormancy and germination are complex adaptive traits of higher plants that are influenced by a large number of genes and environmental factors. Studies of genetics and physiology have shown the important roles of the plant hormones abscisic acid and gibberellin in the regulation of dormancy and germination. More recently, the use of quantitative genetics and mutant approaches has allowed

Maarten Koornneef; Leónie Bentsink; Henk Hilhorst

2002-01-01

125

Dostoevsky: The Seeds of  

E-print Network

Dostoevsky: The Seeds of Revolt, 1821­1849 Also: Dostoevsky: The Years of Ordeal, 1850­1859 [1983] Dostoevsky: The Stir of Libera- tion, 1860­1865 [1986] Dostoevsky: The Miraculous Years, 1865­1871 [1995] Dostoevsky: The Mantle of the Prophet, 1871­1881 [2000] Joseph Frank The term "biography" seems

Landweber, Laura

126

RUSSET BUFFALOBERRY SEEDS  

Microsoft Academic Search

Seed propagation literature for russet buffaloberry (Shepherdia canadensis (L.) Nutt. (Elaeagnaceae)) is varied, recommending acid scarification, cold moist stratification, or both treatments. When combinations of sulfuric acid scarification (0 or 5 min) and stratification (0, 9, or 14 wk) treatments were tested on a Montana seedlot, the optimal treatment combination was a 5- min acid soak and 14-wk (98-d) stratification.

Lee S Rosner; John T Harrington

2003-01-01

127

Acute toxicity and genotoxic activity of avocado seed extract (Persea americana Mill., c.v. Hass).  

PubMed

The use of vegetal extracts requires toxicological and genotoxic evaluations to establish and verify safety before being added to human cosmetic, pharmaceutical medicine, or alimentary products. Persea americana seeds have been used in traditional medicine as treatment for several diseases. In this work, the ethanolic seed extract of Persea americana was evaluated with respect to its genotoxic potential through micronucleus assay in rodents. The frequency of micronuclei in groups of animals treated with avocado seed extract showed no differences compared to the negative control (vehicle); therefore, it is considered that the avocado seed extract showed no genotoxic activity in the micronucleus test. PMID:24298206

Padilla-Camberos, Eduardo; Martínez-Velázquez, Moisés; Flores-Fernández, José Miguel; Villanueva-Rodríguez, Socorro

2013-01-01

128

Acute Toxicity and Genotoxic Activity of Avocado Seed Extract (Persea americana Mill., c.v. Hass)  

PubMed Central

The use of vegetal extracts requires toxicological and genotoxic evaluations to establish and verify safety before being added to human cosmetic, pharmaceutical medicine, or alimentary products. Persea americana seeds have been used in traditional medicine as treatment for several diseases. In this work, the ethanolic seed extract of Persea americana was evaluated with respect to its genotoxic potential through micronucleus assay in rodents. The frequency of micronuclei in groups of animals treated with avocado seed extract showed no differences compared to the negative control (vehicle); therefore, it is considered that the avocado seed extract showed no genotoxic activity in the micronucleus test. PMID:24298206

Padilla-Camberos, Eduardo; Martínez-Velázquez, Moisés; Flores-Fernández, José Miguel; Villanueva-Rodríguez, Socorro

2013-01-01

129

Network models of frugivory and seed dispersal: Challenges and opportunities  

NASA Astrophysics Data System (ADS)

Network analyses have emerged as a new tool to study frugivory and seed dispersal (FSD) mutualisms because networks can model and simplify the complexity of multiple community-wide species interactions. Moreover, network theory suggests that structural properties, such as the presence of highly generalist species, are linked to the stability of mutualistic communities. However, we still lack empirical validation of network model predictions. Here we outline new research avenues to connect network models to FSD processes, and illustrate the challenges and opportunities of this tool with a field study. We hypothesized that generalist frugivores would be important for forest stability by dispersing seeds into deforested areas and initiating reforestation. We then constructed a network of plant-frugivore interactions using published data and identified the most generalist frugivores. To test the importance of generalists we measured: 1) the frequency with which frugivores moved between pasture and forest, 2) the bird-generated seed rain under perches in the pasture, and 3) the perching frequency of birds above seed traps. The generalist frugivores in the forest network were not important for seed dispersal into pastures, and thus for forest recovery, because the forest network excluded habitat heterogeneities, frugivore behavior, and movements. More research is needed to develop ways to incorporate relevant FSD processes into network models in order for these models to be more useful to community ecology and conservation. The network framework can serve to spark and renew interest in FSD and further our understanding of plant-animal communities.

Carlo, Tomás A.; Yang, Suann

2011-11-01

130

Universal Seed Skin Segmentation  

Microsoft Academic Search

\\u000a We present a principled approach for general skin segmentation using graph cuts. We present the idea of a highly adaptive\\u000a universal seed thereby exploiting the positive training data only. We model the skin segmentation as a min-cut problem on\\u000a a graph defined by the image color characteristics. The prior graph cuts based approaches for skin segmentation do not provide\\u000a general

Rehanullah Khan; Allan Hanbury; Julian Stöttinger

2010-01-01

131

USING LOCAL SEEDS IN  

Microsoft Academic Search

Choice among local, non-local, and cultivar seeds for restoring native ecosystems is not purely an academic question—it also has practical consequences. In this article we summarize a series of genetic and competition studies of big bluestem (Andropogon gerardii Vitman. [Poaceae]), Indian grass (Sorghastrum nutans (L.) Nash. [Poaceae]), and purple prairie clover (Dalea purpurea Vent.[Fabaceae]) from remnant and restored Illinois (local)

Danny J Gustafson; David J Gibson; Daniel L Nickrent

2005-01-01

132

Does seeding after wildfires in rangelands reduce erosion or invasive species?  

USGS Publications Warehouse

Mitigation of ecological damage caused by rangeland wildfires has historically been an issue restricted to the western United States. It has focused on conservation of ecosystem function through reducing soil erosion and spread of invasive plants. Effectiveness of mitigation treatments has been debated recently. We reviewed recent literature to conduct a meta-analysis of seeding after wildfires to determine if seedings may (1) protect ecosystems against soil erosion and (2) reduce invasion or abundance of undesirable nonnative plant species. Effectiveness of postfire seedings was examined in 8 erosion and 19 invasive species cases. Seeding has little effect on erosion during the first year after fire and is highly dependent upon initial establishment and coverage of species in successive years. Among all seeding cases, 28% reduced, 67% were neutral, and 5% increased invasive species abundance. Older seedings were more likely to show reductions in invasives than younger seedings. Seedings with high plant establishment were more likely to reduce invasives than those with low establishment. Studies are needed that examine (1) frequency of adequate establishment of postfire seedings and causal factors of success or failure, (2) long-term impacts of seeding along a range of initial establishment and concomitant plant coverage over time as it relates to erosion and abundance of invasive plant species, and (3) auxiliary treatments designed to increase likelihood of germination and establishment given the inevitable variability of environmental conditions. These studies would aid land managers in deciding when postfire treatments are required and their likely level of success.

Pyke, David A.; Wirth, Troy A.; Beyers, Jan L.

2013-01-01

133

Radiobiological experiments with plant seeds aboard the biosatellite Kosmos 1887  

NASA Technical Reports Server (NTRS)

The effects of spaceflight factors on the seeds of Arabidopsis thaliana and Crepis capillaris were studied provided with various protective measures: the seeds were located inside the satellite and in open space, protected with aluminium foil and also exposed without the foil cover. When the seeds were in open space without any protection, their viability was found to be suppressed; the survival rate and fertility of plants grown from these seeds were also diminished. An increase in the frequency of chromosome aberrations (CA) and in the number of multiple injuries was registered in this case. Experiments with the aluminium foil shielding showed a decrease in the suppression of the seeds' viability, but mutational changes were found to be even more increased, while the survival and fertility of the plants decreased. An increase in the thickness of shielding resulted in a decrease in the effects up to the level of the control, except for the effects connected with CA and fertility of the plants. Analysis of the results shows that these impairments can be ascribed to the action of single heavy charged particles (HCP). The seeds can be thus regarded as an integral biological 'dosimeter' which allows estimation of the total effects of radiation, ecological and biological factors.

Anikeeva, I. D.; Vaulina, E. N.; Kostina, L. N.; Marenny, A. M.; Portman, A. I.; Rusin, S. V.; Benton, E. V.

1990-01-01

134

Abstract I present the results of a 2-year experiment comparing seed predation, seed germination, and seed-  

E-print Network

Abstract I present the results of a 2-year experiment comparing seed predation, seed germination are probably due to lower levels of seed germination. Forest fragments have higher air and soil temperatures into plant conservation efforts. Keywords Habitat fragmentation · Heliconiaceae · Seed germination · Seed

Bruna, Emilio M.

135

Differential seed handling by two African primates affects seed fate and establishment of large-seeded trees  

NASA Astrophysics Data System (ADS)

We examined the influence of seed handling by two semi-terrestrial African forest primates, chimpanzees ( Pan troglodytes) and l'Hoest's monkeys ( Cercopithecus lhoesti), on the fate of large-seeded tree species in an afromontane forest. Chimpanzees and l'Hoest's monkeys dispersed eleven seed species over one year, with quantity and quality of dispersal varying through time. Primates differed in their seed handling behaviors with chimpanzees defecating large seeds (>0.5 cm) significantly more than l'Hoest's. Furthermore, they exhibited different oral-processing techniques with chimpanzees discarding wadges containing many seeds and l'Hoest's monkeys spitting single seeds. A PCA examined the relationship between microhabitat characteristics and the site where primates deposited seeds. The first two components explained almost half of the observed variation. Microhabitat characteristics associated with sites where seeds were defecated had little overlap with those characteristics describing where spit seeds arrived, suggesting that seed handling in part determines the location where seeds are deposited. We monitored a total of 552 seed depositions through time, recording seed persistence, germination, and establishment. Defecations were deposited significantly farther from an adult conspecific than orally-discarded seeds where they experienced the greatest persistence but poorest establishment. In contrast, spit seeds were deposited closest to an adult conspecific but experienced the highest seed establishment rates. We used experimental plots to examine the relationship between seed handling, deposition site, and seed fate. We found a significant difference in seed handling and fate, with undispersed seeds in whole fruits experiencing the lowest establishment rates. Seed germination differed by habitat type with open forest experiencing the highest rates of germination. Our results highlight the relationship between primate seed handling and deposition site and seed fate, and may be helpful in developing models to predict seed shadows and recruitment patterns of large-seeded trees.

Gross-Camp, Nicole D.; Kaplin, Beth A.

2011-11-01

136

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Certified seed potatoes, and seed corn or maize. 10.57 ...REDUCED RATE, ETC. General Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim...

2010-04-01

137

7 CFR 201.30 - Hard seed.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Hard seed. 201.30 Section 201.30 Agriculture...REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed, if any is present, for any seed...

2010-01-01

138

7 CFR 201.21 - Hard seed.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Hard seed. 201.21 Section 201.21 Agriculture... Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard seed, if any is present, for any seed...

2010-01-01

139

Seed Dispersal by Japanese Macaques  

Microsoft Academic Search

\\u000a Seed dispersal is a crucial process in recruitment of plant populations, as well as for pollen dispersal. The location of\\u000a dispersed seeds affects the survival of seedlings and the spatial distribution pattern of plants. Plants employ various strategies\\u000a for effective seed dispersal, and diaspores have unique structures that utilize biotic and\\/or abiotic factors such as fleshy\\u000a arils for endozoochory, thorny

Tatsuya Otani

140

Alfalfa… for Forage and Seed.  

E-print Network

' ........................................................... Alfalfa Cultivation II 1 ; ........................................................................ Weed Control Il i ALFALFA . . . for Forage and Seed ~ E. M. TREW, Extension Agronomist TEXAS A. & M. COLLEGE SYSTEM u*r AND SEED are the most important... may be seeded into a dead stubble of sorghum, Sudan- grass or small grain. If cultivation is necessary to control weeds, use implements that allow shal- low, subsurface tillage with the stubble left on the soil surface. Weedy growth also may...

Trew, E. M.

1957-01-01

141

Metal deposition using seed layers  

DOEpatents

Methods of forming a conductive metal layers on substrates are disclosed which employ a seed layer to enhance bonding, especially to smooth, low-roughness or hydrophobic substrates. In one aspect of the invention, the seed layer can be formed by applying nanoparticles onto a surface of the substrate; and the metallization is achieved by electroplating an electrically conducting metal onto the seed layer, whereby the nanoparticles serve as nucleation sites for metal deposition. In another approach, the seed layer can be formed by a self-assembling linker material, such as a sulfur-containing silane material.

Feng, Hsein-Ping; Chen, Gang; Bo, Yu; Ren, Zhifeng; Chen, Shuo; Poudel, Bed

2013-11-12

142

Post-fire seeding on Wyoming big sagebrush ecological sites: regression analyses of seeded nonnative and native species densities.  

PubMed

Since the mid-1980s, sagebrush rangelands in the Great Basin of the United States have experienced more frequent and larger wildfires. These fires affect livestock forage, the sagebrush/grasses/forbs mosaic that is important for many wildlife species (e.g., the greater sage grouse (Centrocercus urophasianus)), post-fire flammability and fire frequency. When a sagebrush, especially a Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis (Beetle & A. Young)), dominated area largely devoid of herbaceous perennials burns, it often transitions to an annual dominated and highly flammable plant community that thereafter excludes sagebrush and native perennials. Considerable effort is devoted to revegetating rangeland following fire, but to date there has been very little analysis of the factors that lead to the success of this revegetation. This paper utilizes a revegetation monitoring dataset to examine the densities of three key types of vegetation, specifically nonnative seeded grasses, nonnative seeded forbs, and native Wyoming big sagebrush, at several points in time following seeding. We find that unlike forbs, increasing the seeding rates for grasses does not appear to increase their density (at least for the sites and seeding rates we examined). Also, seeding Wyoming big sagebrush increases its density with time since fire. Seeding of grasses and forbs is less successful at locations that were dominated primarily by annual grasses (cheatgrass (Bromus tectorum L.)), and devoid of shrubs, prior to wildfire. This supports the hypothesis of a "closing window of opportunity" for seeding at locations that burned sagebrush for the first time in recent history. PMID:18790557

Eiswerth, Mark E; Krauter, Karl; Swanson, Sherman R; Zielinski, Mike

2009-02-01

143

Seed-cotton Cleaning Effects on Seed Coat Fragments  

Technology Transfer Automated Retrieval System (TEKTRAN)

Processing problems in textile mills have been linked to seed coat fragments (SCF), so cotton ginning facilities should take steps to prevent them from forming. The objective of this experiment was to determine if the use of seed-cotton cleaners prior to the extractor-feeder/gin stand caused increa...

144

Seed Coat Cracking in Soybean Isolines for Pubescence Color and Maturity.  

PubMed

Seed coats of soybean crack under various stress conditions. Cracking of seed coats degrades the external appearance of soybean seeds and reduces their commercial value. Previous studies revealed that the T gene responsible for pubescence color, and the maturity genes, E1 and E5, had inhibitory effects on low-temperature induced seed coat cracking. The objective of this study was to evaluate the effects of the T gene and five maturity genes (E1 to E5) on the intensity of seed coat cracking induced by pod-removal treatments. Soybean cv. Harosoy (te1e2E3E4e5) and its near-isogenic lines for T and E1 to E5 loci were used in the experiment. Cracking was induced by removing the upper 50% of pods on the plant 40 d after anthesis. Frequency and degree of cracking were not different among the isolines in the control group. In contrast, there were significant differences among isolines subjected to the pod-removal treatment. Frequency and degree of cracking was low in Harosoy, Harosoy-E1, e3, and e4, and high in Harosoy-T and E2. The results suggest that genotypes at T and E2 loci were associated with severity of seed coat cracking induced by pod-removal. There was a positive correlation (r = 0.90**) between individual seed weight and frequency of cracking among isolines in the pod-removal treatment. Seed coat cracking was probably exacerbated in part by the genes that allow enlargement of individual seeds in response to pod-removal. The differences among isolines suggest that the mechanism of seed coat cracking induced by pod removal may differ from that induced by low temperature treatment. PMID:11756256

Yang, Daijun; Nakamura, Takehiro; Ohtsubo, Norihiro; Takahashi, Koji; Abe, Jun; Takahashi, Ryoji

2002-01-01

145

A guide to forest seed handling  

SciTech Connect

This guide to forest seed handling focuses on seed quality, i.e., the physiological viability and vigor of the seeds. Seed and fruit development, germination, and dormancy and the fundamentals of planning seed collections are covered. The guide includes discussions on seed collection of fallen fruits or seeds from the forest floor from the crowns of felled trees, and from standing trees with access from the ground and with other means of access. Also considered are precautions to be followed during fruit and seed handling between collection and processing. The different stages in seed processing are detailed, including extraction, depulping, drying, tumbling and threshing, dewinging, cleaning, grading, and mixing. Factors affecting seed longevity in storage and the choice of storage methods are reviewed. Different forms of seed pretreatment and seed testing methods are described.

Willan, R.L.

1986-01-01

146

Rangeland Risk Management for Texans: Seeding Rangeland  

E-print Network

planting method. If drilling is not practical, soil/seed contact can be improved by disturbing the soil with roller chopping or ?lite? raking before seed is broadcast. Seeding often follows brush control treatments, especially root plowing. The least...

Rector, Barron S.

2000-11-01

147

Teaching Through Trade Books: Secrets of Seeds  

NSDL National Science Digital Library

From a tiny radish seed to a giant coconut, seeds come in a multitude of shapes and sizes. They all share one amazing secret: the potential to grow into a new plant when conditions are right. In this month's column, students observe a variety of seeds, match seeds to the plants they grow into, explore what seeds need to germinate and grow, and design investigations with seeds.

Morgan, Emily; Ansberry, Karen

2009-02-01

148

Spatial and temporal genetic differentiation among the seed in a stand of Fagus sylvatica L  

Microsoft Academic Search

In a beech population composed of three parts (demes), the genetic structure of the seed (after dispersal) of each deme was recorded in two successive years and at five protein loci, four of which were polymorphic. Spatial and temporal differentiation, as evidenced in allele frequencies, genie diversity and heterozygosity, was studied. While no differentiation was found for diversity, allele frequencies

H-R Gregorius; J Krauhausen; G Müller-Starck

1986-01-01

149

Microwave drying of seed cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

A small lab dryer was designed for use in drying seed cotton with components of a microwave generator mounted thereon. The magnetron emitted radiation directly into the seed cotton and a fan directed air cross-flow to the radiation direction. The microwave components were a 1.1 kW magnetron, trans...

150

Seed dormancy in alpine species.  

PubMed

In alpine species the classification of the various mechanisms underlying seed dormancy has been rather questionable and controversial. Thus, we investigated 28 alpine species to evaluate the prevailing types of dormancy. Embryo type and water impermeability of seed coats gave an indication of the potential seed dormancy class. To ascertain the actual dormancy class and level, we performed germination experiments comparing the behavior of seeds without storage, after cold-dry storage, after cold-wet storage, and scarification. We also tested the light requirement for germination in some species. Germination behavior was characterized using the final germination percentage and the mean germination time. Considering the effects of the pretreatments, a refined classification of the prevailing dormancy types was constructed based on the results of our pretreatments. Only two out of the 28 species that we evaluated had predominantly non-dormant seeds. Physiological dormancy was prevalent in 20 species, with deep physiological dormancy being the most abundant, followed by non-deep and intermediate physiological dormancy. Seeds of four species with underdeveloped embryos were assigned to the morphophysiologial dormancy class. An impermeable seed coat was identified in two species, with no additional physiological germination block. We defined these species as having physical dormancy. Light promoted the germination of seeds without storage in all but one species with physiological dormancy. In species with physical dormancy, light responses were of minor importance. We discuss our new classification in the context of former germination studies and draw implications for the timing of germination in the field. PMID:24415831

Schwienbacher, Erich; Navarro-Cano, Jose Antonio; Neuner, Gilbert; Erschbamer, Brigitta

2011-10-01

151

Two light yellow seed embryos  

NSDL National Science Digital Library

The style of the carpel of a flower (female reproductive structure) leads to the ovary. The ovary holds eggs, which become seeds once fertilized. Seeds hold embryos. The embryo becomes a new plant. In animals, the embryo becomes a new animal.

Katie Hale (CSUF; Biological Sciences)

2007-06-19

152

Differential predation of forage seed  

Technology Transfer Automated Retrieval System (TEKTRAN)

In recent field experiments we observed that the main invertebrate seed predators of overseeded tall fescue (Festuca arundinacea Schreb.) or Italian ryegrass (Lolium multiflorum Lam.) seed in unimproved pastures were harvester ants (Pogonomyrmex sp.) and common field crickets (Gryllus sp.) To determ...

153

Onion Seed Production in California  

E-print Network

Onion Seed Production in California RONALD E. VOSS, Cooperative Extension Vegetable Specialist for onion (Allium cepa, L.) in California occurs pri- marily in the low desert of Imperial County areas. Onion seed production in the desert includes open-pollinated dehydrator varieties as well

Bradford, Kent

154

Training for Certification: Seed Treatment.  

ERIC Educational Resources Information Center

This Cooperative Extension Service publication from Mississippi State University is a training guide for commercial pesticide applicators. Focusing specifically on the treatment of seeds with pesticides, this publication is meant to prepare one to take the written examination for Environmental Protection Agency Seed Treatment certification.…

Mississippi State Univ., State College. Cooperative Extension Service.

155

Insecticide seed treatments for sugarbeet  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pest feeding and vectoring of viruses cause serious problems in sugarbeet production worldwide. In order to ameliorate pest and disease problems on sugarbeet, two seed treatments, Poncho Beta (60 g a.i. clothianidin + 8 g a.i. beta-cyfluthrin/100,000 seed) and Cruiser Tef (60 g a.i. thiamethoxam + 8...

156

The Saponin of Fenugreek Seeds  

Microsoft Academic Search

THE presence of a saponin in the seeds of Trigonella Foenum groecum (Leguminosæ) was first reported by Wunschendorff1, who had subjected the defatted seeds to a process of extraction with alcohol. He obtained from the alcoholic extract a gelatinous precipitate which was afterwards dissolved in alcohol and reprecipitated with ether. Wunschendorff described the product so obtained as a white semicrystalline

Gabra Soliman; Zahira Mustafa

1943-01-01

157

Implications of nonrandom seed abscission and global stilling for migration of wind-dispersed plant species.  

PubMed

Migration of plant populations is a potential survival response to climate change that depends critically on seed dispersal. Biological and physical factors determine dispersal and migration of wind-dispersed species. Recent field and wind tunnel studies demonstrate biological adaptations that bias seed release toward conditions of higher wind velocity, promoting longer dispersal distances and faster migration. However, another suite of international studies also recently highlighted a global decrease in near-surface wind speeds, or 'global stilling'. This study assessed the implications of both factors on potential plant population migration rates, using a mechanistic modeling framework. Nonrandom abscission was investigated using models of three seed release mechanisms: (i) a simple drag model; (ii) a seed deflection model; and (iii) a 'wear and tear' model. The models generated a single functional relationship between the frequency of seed release and statistics of the near-surface wind environment, independent of the abscission mechanism. An Inertial-Particle, Coupled Eulerian-Lagrangian Closure model (IP-CELC) was used to investigate abscission effects on seed dispersal kernels and plant population migration rates under contemporary and potential future wind conditions (based on reported global stilling trends). The results confirm that nonrandom seed abscission increased dispersal distances, particularly for light seeds. The increases were mitigated by two physical feedbacks: (i) although nonrandom abscission increased the initial acceleration of seeds from rest, the sensitivity of the seed dispersal to this initial condition declined as the wind speed increased; and (ii) while nonrandom abscission increased the mean dispersal length, it reduced the kurtosis of seasonal dispersal kernels, and thus the chance of long-distance dispersal. Wind stilling greatly reduced the modeled migration rates under biased seed release conditions. Thus, species that require high wind velocities for seed abscission could experience threshold-like reductions in dispersal and migration potential if near-surface wind speeds continue to decline. PMID:23505130

Thompson, Sally E; Katul, Gabriel G

2013-06-01

158

The use of certified seeds of improved wheat varieties in farms and the contributions of certified seed usage to enterprise economies: the case of Ankara province in Turkey.  

PubMed

In this research, the use of certificated seeds of improved wheat varieties in farms of Ankara, which have an important share in wheat production of Turkey and the contributions of the certified seeds usage to enterprise economy have been evaluated by using data collected from farms via a questionnaire. The low level of use of certificated wheat seed in farms is associated with many factors, such as price of the seed (cost), yield gains and suitability of the varieties for the farming aims of producers. Average productivity is 49.5% and average net profit is 39.7% higher in the production of wheat with certificated seeds of improved varieties in farms in comparison to farming with traditional varieties. Average productivity in wheat production with uncertified seeds of improved varieties is 24.9% and net profit per unit area is 24.3% higher than wheat production with traditional varieties. The net economic benefit of wheat production using certificated seeds of improved varieties and that of wheat farming with uncertified seeds has been estimated at $ 102.40 and $ 62.70 ha(-1), respectively. Some $ 6.4 benefit is generated in return for $ 1 of expense in wheat farming with certificated seeds of improved varieties instead of traditional varieties. In the absence of state subsidies for certificated seeds the use of uncertified seeds seems to be advantageous for producers. While the amount of subsidy per hectare will be a minimum of $ 101 for certificated seeds per hectare of planting area (as technological improvement), the support will be encouraging for usage of certified seeds. Many variables, such as farm size, use of certified seeds, topography of land, production system, education level and frequency of visiting the agriculture organizations of the producers influence the level of gross profit per unit area in wheat farming. Low level of use of certificated seed in farms decreases the economic benefit of new varieties which are developed as a result of long term research and development studies and with a large amount of expense and causes the return of expenses to take a long time, if ever. PMID:19093496

Tanrivermi?, Harun; Akdo?an, Ilyas

2007-12-15

159

The Composition of Cotton Seed Meal and Cotton Seed.  

E-print Network

] THE COMPOSITION OF COTTONSEED MEAL AND COTTON SEED G. S. Fr,-\\r,s, ('11~111~~ 'l'0 THE ESZ-'ERIJTENT ST- TIO ON. This l~ulletin contains a discussion of tlie composition of cotton- seed n~eal so!d ill Texas ancl in other States, wit11 a description of tl~c... lnethocl of milling and with some discussion of the effect of niill- il1.r on the compo~ition of the meal. Some work on the compositioi~ of cotton seed is also given. ,4ccording to Bulletin 131, Bureau of the (2elecsus, in 1914 tl~erc \\-rere 885 c...

Fraps, G. S. (George Stronach)

1916-01-01

160

Seed biology and in vitro seed germination of Cypripedium.  

PubMed

Cypripedium orchids have high horticultural value. The populations of most species are very geographically restricted and they are becoming increasingly rare due to the destruction of native habitats and illegal collection. Reduction of the commercial value through large-scale propagation in vitro is a preferable option to reduce pressure from illegal collection. Cypripedium species are commercially propagated via seed germination in vitro. This review focuses on in vitro seed germination and provides an in-depth analysis of the seed biology of this genus. PMID:24191720

Zeng, Songjun; Zhang, Yu; Teixeira da Silva, Jaime A; Wu, Kunlin; Zhang, Jianxia; Duan, Jun

2014-12-01

161

[Effect of decimeter polarized electromagnetic radiation on germinating capacity of seeds].  

PubMed

The effect of a polarization structure of electromagnetic radiation on the germinating capacity of seeds of such weeds as Green foxtail (Setaria viridis) and Green amaranth (Amaranthus retroflexus) has been studied. Seeds have been exposed to impulse electromagnetic radiation in a frequency of 896 MHz with linear, elliptical right-handed and elliptical left-handed polarizations at different power flux density levels. It is determined that the effect of the right-handed polarized electromagnetic radiation increases and the influence of the left-handed polarized one reduces the germinating capacity of seeds compared to the effect of the linearly polarized electromagnetic radiation. It is shown that the seeds have an amplitude polarization selectivity as evinced by the major effect of the right-handed polarized radiation on seeds. An electrodynamic model as the right-handed elliptically polarized antenna with the given quantity of the ellipticity of polarization is suggested to use in description of this selectivity. PMID:24455890

Polevik, N D

2013-01-01

162

Laser seeding of the storage-ring microbunching instability for high-power coherent terahertz radiation.  

PubMed

We report the first observation of laser seeding of the storage-ring microbunching instability. Above a threshold bunch current, the interaction of the beam and its radiation results in a coherent instability, observed as a series of stochastic bursts of coherent synchrotron radiation (CSR) at terahertz frequencies initiated by fluctuations in the beam density. We have observed that this effect can be seeded by imprinting an initial density modulation on the beam by means of laser "slicing." In such a situation, most of the bursts of CSR become synchronous with the pulses of the modulating laser and their average intensity scales exponentially with the current per bunch. We present detailed experimental observations of the seeding effect and a model of the phenomenon. This seeding mechanism also creates potential applications as a high-power source of CSR at terahertz frequencies. PMID:17026236

Byrd, J M; Hao, Z; Martin, M C; Robin, D S; Sannibale, F; Schoenlein, R W; Zholents, A A; Zolotorev, M S

2006-08-18

163

Seed characters and organ size in the cytotaxonomy of Rumex acetosella L  

Microsoft Academic Search

Angiocarpic seeds occur in diploid, tetraploid and hexaploid populations of Rumex acetosella s.l.- gymnocarpic seeds occur in tetraploids and hexaploids only, and among the hexaploids in populations from northern and central Europe.Cell and organ sizes do not rigorously correspond with the various levels of ploidy, and the overlap in range and frequency results in monomodal distributions.All New Zealand populations are

W. Harris

1969-01-01

164

Effects of prolonged exposure to space flight factors for 175 days on lettuce seeds  

NASA Astrophysics Data System (ADS)

We have studied the effects of prolonged (up to 175 days) exposure of Lactuca sativa seeds to space flight factors, including primary cosmic radiation heavy ions. The data obtained evidence a significant fourfold increase ofs pontaneous mutagenesis in seeds both with regard to the total number of aberrant cells as well as the formation of single cells with multiple aberrations. Comparison of the present experiment with earlier works shows that the frequency of such aberrations increases with the duration of the flight.

Nevzgodina, L. V.; Maximova, E. N.; Akatov, Yu. A.

165

Effects of seed maturity, seed storage and pre-germination treatments on seed germination of cleome ( Cleome gynandra L.)  

Microsoft Academic Search

The influence of seed maturity, seed storage and germination pre-treatments on seed germination of cleome (Cleome gynandra L.) were investigated. Seed maturation studies showed that capsules harvested at 18 days after anthesis possessed the highest dry weight with 19.2% moisture and 1% germination. Development of fresh-ungerminated seed was observed with increasing maturity of fruit, suggesting that cleome exhibited forms of

Boonsong Ekpong

2009-01-01

166

Make a Friend from Soil and Seeds  

NSDL National Science Digital Library

Learners assemble a figure from a nylon stocking or sock stuffed with soil and seeds. The ends of the nylons inside the jar absorb water, which feeds the grass seeds. The seeds grow to become grassy hair for the figure, and the rest of the stuffed nylon becomes the body of the figure. Use this activity to illustrate the process of seed germination.

Museum Of Science And Industry, Chicago

2012-01-01

167

46 CFR 148.310 - Seed cake.  

Code of Federal Regulations, 2011 CFR

...Special Requirements for Certain Materials § 148.310 Seed cake. (a) This part does not apply to solvent-extracted rape seed meal, pellets, soya bean meal, cotton seed meal, or sunflower seed meal that— (1) Contains a maximum of 4...

2011-10-01

168

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2010-01-01

169

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2012-01-01

170

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2013-01-01

171

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2014-01-01

172

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2011-01-01

173

7 CFR 948.6 - Seed potatoes.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Seed potatoes. 948.6 Section 948.6 Agriculture...DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN COLORADO Order Regulating Handling Definitions § 948.6 Seed potatoes. Seed potatoes or seed means...

2010-01-01

174

SEED ORCHARDS ON RECLAIMED MINED LAND  

Microsoft Academic Search

Reclaimed mined lands often have restricted public access, a situation that could encourage sagebrush seed growers to invest in methods for increasing seed production and improving seed purity and quality. I tested the agronomic benefit of 2 seeding methods and fabric mulch and a cross-linked polyacrylamide polymer soil amendment by using these practices to establish 3 Wyoming big sagebrush (Artemisia

D Terrance Booth

2005-01-01

175

Transform-limited, achromatic injection-seeded terahertz-wave parametric generator  

Microsoft Academic Search

A review to our effort on developing the transform-limited, frequency-agile terahertz-wave parametric generator (TPG) is presented. A frequency-agile THz-wave generation is realized by introducing the injection-seeding method and the optical design for the stationary dispersion-compensation The purity of the THz-wave frequency was dramatically improved to Deltav\\/v<10-4. Simultaneously, the THz-wave output was several hundred times higher than that of a conventional

R. Guo; H. Minamide; H. Ito

2011-01-01

176

Comments on relationships between native seed preferences of shrub-steppe granivores and seed nutritional characteristics  

Microsoft Academic Search

Kelrick et al. (1986) argued that seed preferences of desert granivores are strongly influenced by soluble carbohydrate contents of native seed species. They assumed that bitterbrush (Purshia tridentata) seeds are eaten in their entirety by rodents, but in fact these granivores eat only embryos of bitterbrush seeds. Embryos have a much lower percentage of soluble carbohydrate than whole bitterbrush seeds,

Stephen H. Jenkins

1988-01-01

177

Effects of rodent species, seed species, and predator cues on seed fate  

Microsoft Academic Search

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation

Kelly J. Sivy; Steven M. Ostoja; Eugene W. Schupp; Susan Durham

2011-01-01

178

INCORPORATING ANIMAL BEHAVIOR INTO SEED DISPERSAL MODELS: IMPLICATIONS FOR SEED SHADOWS  

Microsoft Academic Search

Seed dispersal fundamentally influences plant population and community dynamics but is difficult to quantify directly. Consequently, models are frequently used to describe the seed shadow (the seed deposition pattern of a plant population). For vertebrate- dispersed plants, animal behavior is known to influence seed shadows but is poorly integrated in seed dispersal models. Here, we illustrate a modeling approach that

Sabrina E. Russo; Stephen Portnoy; Carol K. Augspurger

2006-01-01

179

Change of seed germination rate with storage time of Santalum album L. (Indian sandalwood) seeds  

E-print Network

Change of seed germination rate with storage time of Santalum album L. (Indian sandalwood) seeds Y of accommodating 100 seeds per bed. Cleaned river sand was used as the germination media that was filled.5 cm. In order to avoid the common fungal attacks on sandalwood seeds, the seeds and the germination

180

Quantification and modeling of plasmid mobilization on seeds and roots.  

PubMed

Mobilization frequencies of the nonconjugative plasmid pMON5003 were quantified using Escherichia coli TB1(pRK2013) as donor of a helper plasmid, E. coli M182 (pMON5003) as donor of the nonconjugative plasmid, and Pseudomonas fluorescens as recipient. Initial mating experiments were conducted in nutrient and minimal salts media and pea seed exudates. Mobilization rates were higher during early stationary growth of donors, helpers, and recipients. Numbers of transconjugants were higher in biparental matings when donors contained both conjugative and nonconjugative plasmids, versus tri-parental matings. A mathematical model was developed to predict a nonconjugative plasmid transfer rate parameter (delta), estimating the proportion of conjugative matings in which a plasmid is mobilized. Values of delta ranged from 8 x 10(-3) to 7.9 x 10(-1). Transfer frequencies for pMON5003 from E. coli to P. fluorescens on pea seeds and roots were determined. Transconjugants (P. fluorescens 2-79 (pMON5003)) were isolated from seeds, roots, and soil, but mobilization frequencies were lower than in liquid media. PMID:16732455

Sudarshana, Padma; Knudsen, Guy R

2006-06-01

181

Echo-Enabled Harmonic Generation for Seeded FELs  

SciTech Connect

In the x-ray wavelengths, the two leading FEL concepts are the self-amplified spontaneous emission (SASE) configuration and the high-gain harmonic generation (HGHG) scheme. While the radiation from a SASE FEL is coherent transversely, it typically has rather limited temporal coherence. Alternatively, the HGHG scheme allows generation of fully coherent radiation by up-converting the frequency of a high-power seed laser. However, due to the relatively low up-frequency conversion efficiency, multiple stages of HGHG FEL are needed in order to generate x-rays from a UV laser. The up-frequency conversion efficiency can be greatly improved with the recently proposed echo-enabled harmonic generation (EEHG) technique. In this work we will present the concept of EEHG, and address some practically important issues that affect the performance of the seeding. We show how the EEHG can be incorporated in the FEL scheme and what is the expected performance of the EEHG seeded FEL. We will then briefly describe the first proof-of-principle EEHG experiment carried out at the Next Linear Collider Test Accelerator (NLCTA) at SLAC. We will also discuss latest advances in the echo-scheme approach, and refer to subsequent modifications of the original concept.

Stupakov, G.; /SLAC

2011-05-19

182

Seeding for pervasively overlapping communities  

NASA Astrophysics Data System (ADS)

In some social and biological networks, the majority of nodes belong to multiple communities. It has recently been shown that a number of the algorithms specifically designed to detect overlapping communities do not perform well in such highly overlapping settings. Here, we consider one class of these algorithms, those which optimize a local fitness measure, typically by using a greedy heuristic to expand a seed into a community. We perform synthetic benchmarks which indicate that an appropriate seeding strategy becomes more important as the extent of community overlap increases. We find that distinct cliques provide the best seeds. We find further support for this seeding strategy with benchmarks on a Facebook network and the yeast interactome.

Lee, Conrad; Reid, Fergal; McDaid, Aaron; Hurley, Neil

2011-06-01

183

Getting Acquainted with a Seed  

NSDL National Science Digital Library

Description: In this activity students become acquainted with the anatomy and biology of seeds. They will use lenses and scales and make drawings to scale. Students will measure and calculate magnifications and they will begin to understand relationships among these. They will organize and summarize their data and, as they do so, they will be developing the understanding and skills needed to undertake more detailed investigations on the biology and reproduction of Fast Plants.Learning ObjectivesThis activity is designed to strengthen students' observational and quantitative skills. In participating in this activity students will:- learn to use magnifying lenses, microscopes and dissecting tools for detailed observation; - measure scales with rulers; - draw to scale, with accuracy and precision to understand scale and magnification; - learn features of the external anatomy of seeds that are associated with certain features of the internal anatomy of seeds; and - estimate the amount of water required to be taken up by seeds in order to initiate germination.

The Wisconsin Fast Plants Program

184

SWEEPER: An Efficient Disaster Recovery Point Identification Mechanism  

Microsoft Academic Search

Data corruption is one of the key problems that is on top of the radar screen of most CIOs. Continuous Data Protection (CDP) technologies help enterprises deal with data corruption by maintaining multiple versions of data and facilitating recovery by allowing an administrator re- store to an earlier clean version of data. The aim of the recovery process after data

Akshat Verma; Kaladhar Voruganti; Ramani Routray; Rohit Jain

2008-01-01

185

Holographic laser sweeper for in-process debris removal  

NASA Astrophysics Data System (ADS)

Debris deposited around laser-processed structures is a critical issue in high-precision laser processing and should be removed. We demonstrated a new debris removal method that is performed during laser processing. A line-focused beam that is radiated onto a target material simultaneously with a processing beam sweeps away the debris generated by laser ablation. Two physical processes are involved: One is direct photon excitation of the attached debris, similar to laser ablation, due to a smaller ablation threshold of the debris, and the other is blowing away the debris with a laser-induced pressure wave. The laser processing setup for debris sweeping has a simple and practical configuration composed of beam transmission optics from a laser source to the target and a spatial light modulator that displays a computer-generated hologram. This in-process debris removal method has the advantages of needing no additional equipment other than the optics, no additional operations, no special materials, and no specific operating environment.

Sakuma, Kazuki; Hasegawa, Satoshi; Takahashi, Hidetomo; Ota, Michiharu; Hayasaki, Yoshio

2015-01-01

186

Deep-ultraviolet frequency metrology with a narrowband titanium:sapphire laser  

Microsoft Academic Search

Within the framework of this thesis resaerch project a narrow band titanium:sapphire laser was built. It provides nanosecond pulses that are subsequently upconverted to the deep ultraviolet frequency range. Absolute frequency calibration is achieved by linking the injection seeding light to a femtosecond frequency comb. Doppler shifts were minimized using an interferometric alignment scheme. Chirp analysis techniques are applied to

S. Hannemann

2007-01-01

187

Can Soil Seed Banks Serve as Genetic Memory? A Study of Three Species with Contrasting Life History Strategies  

PubMed Central

We attempted to confirm that seed banks can be viewed as an important genetic reservoir by testing the hypothesis that standing (aboveground) plants represent a nonrandom sample of the seed bank. We sampled multilocus allozyme genotypes from three species with different life history strategies: Amaranthus retroflexus, Carduus acanthoides, Pastinaca sativa. In four populations of each species we analysed the extent to which allele and genotype frequencies vary in consecutive life history stages including the summer seed bank, which has been overlooked up to now. We compared the winter seed bank (i.e., seeds collected before the spring germination peak), seedlings, rosettes, the summer seed bank (i.e., seeds collected after the spring germination peak) and fruiting plants. We found that: (1) All three species partitioned most of their genetic diversity within life history stages and less among stages within populations and among populations. (2) All genetic diversity parameters, except for allele frequencies, were similar among all life history stages across all populations in different species. (3) There were differences in allele frequencies among life history stages at all localities in Amaranthus retroflexus and at three localities in both Carduus acanthoides and Pastinaca sativa. (4) Allele frequencies did not differ between the winter and summer seed bank in most Carduus acanthoides and Pastinaca sativa populations, but there was a marked difference in Amaranthus retroflexus. In conclusion, we have shown that the summer seed bank is not genetically depleted by spring germination and that a majority of genetic diversity remains in the soil through summer. We suggest that seed banks in the species investigated play an important role by maintaining genetic diversity sufficient for recovery rather than by accumulating new genetic diversity at each locality. PMID:23185340

Mandák, Bohumil; Zákravský, Petr; Mahelka, Václav; Pla?ková, Ivana

2012-01-01

188

Can soil seed banks serve as genetic memory? A study of three species with contrasting life history strategies.  

PubMed

We attempted to confirm that seed banks can be viewed as an important genetic reservoir by testing the hypothesis that standing (aboveground) plants represent a nonrandom sample of the seed bank. We sampled multilocus allozyme genotypes from three species with different life history strategies: Amaranthus retroflexus, Carduus acanthoides, Pastinaca sativa. In four populations of each species we analysed the extent to which allele and genotype frequencies vary in consecutive life history stages including the summer seed bank, which has been overlooked up to now. We compared the winter seed bank (i.e., seeds collected before the spring germination peak), seedlings, rosettes, the summer seed bank (i.e., seeds collected after the spring germination peak) and fruiting plants. We found that: (1) All three species partitioned most of their genetic diversity within life history stages and less among stages within populations and among populations. (2) All genetic diversity parameters, except for allele frequencies, were similar among all life history stages across all populations in different species. (3) There were differences in allele frequencies among life history stages at all localities in Amaranthus retroflexus and at three localities in both Carduus acanthoides and Pastinaca sativa. (4) Allele frequencies did not differ between the winter and summer seed bank in most Carduus acanthoides and Pastinaca sativa populations, but there was a marked difference in Amaranthus retroflexus. In conclusion, we have shown that the summer seed bank is not genetically depleted by spring germination and that a majority of genetic diversity remains in the soil through summer. We suggest that seed banks in the species investigated play an important role by maintaining genetic diversity sufficient for recovery rather than by accumulating new genetic diversity at each locality. PMID:23185340

Mandák, Bohumil; Zákravský, Petr; Mahelka, Václav; Pla?ková, Ivana

2012-01-01

189

Dormancy studies in blackberry seed  

E-print Network

. Percentage carbohydrate changes in blackberry seed during 7 months of after-ripening at room temperature........ 64 11. Catalase, peroxidase, and lipase activities of embryos of blackberry after various months of cold after-ripening at 3 to 5 degrees C..., peroxidases, oxidases and lipases, and probably also of proteases. At the same time there are changes in the stored food reserves of the seed: fats are converted in? to sugars, and insoluble proteins into soluble proteins, amino acids and other organic...

Lasheen, Abdel Moty

1954-01-01

190

Seed dormancy and ABA signaling  

PubMed Central

The seed is an important organ in higher plants, it is an important organ for plant survival and species dispersion. The transition between seed dormancy and germination represents a critical stage in the plant life cycle and it is an important ecological and commercial trait. A dynamic balance of synthesis and catabolism of two antagonistic hormones, abscisic acid (ABA) and giberellins (GAs), controls the equilibrium between seed dormancy and germination. Embryonic ABA plays a central role in induction and maintenance of seed dormancy and also inhibits the transition from embryonic to germination growth. Therefore, the ABA metabolism must be highly regulated at both temporal and spatial levels during phase of dessication tolerance. On the other hand, the ABA levels do not depend exclusively on the seeds because sometimes it becomes a strong sink and imports it from the roots and rhizosphere through the xylem and/or phloem. These events are discussed in depth here. Likewise, the role of some recently characterized genes belonging to seeds of woody species and related to ABA signaling are also included. Finally, although four possible ABA receptors have been reported, not much is known about how they mediate ABA signaling transduction. However, new publications seem to show that almost all these receptors lack several properties to consider them as such. PMID:19875942

del Carmen Rodríguez-Gacio, María; Matilla-Vázquez, Miguel A

2009-01-01

191

Multiple frequency optical mixer and demultiplexer and apparatus for remote sensing  

NASA Technical Reports Server (NTRS)

A pulsed laser system includes a modulator module configured to provide pulsed electrical signals and a plurality of solid-state seed sources coupled to the modulator module and configured to operate, responsive to the pulsed electrical signals, in a pulse mode. Each of the plurality of solid-state seed sources is tuned to a different frequency channel separated from any adjacent frequency channel by a frequency offset. The pulsed laser system also includes a combiner that combines outputs from each of the solid state seed sources into a single optical path and an optical doubler and demultiplexer coupled to the single optical path and providing each doubled seed frequency on a separate output path.

Chen, Jeffrey R. (Inventor)

2010-01-01

192

Effect of seed predation on seed bank size and seedling recruitment of bush lupine ( Lupinus arboreus )  

Microsoft Academic Search

Whether seed consumers affect plant establishment is an important unresolved question in plant population biology. Seed consumption\\u000a is ubiquitous; at issue is whether seedling recruitment is limited by safe-sites or seeds. If most seeds inhabit sites unsuitable\\u000a for germination, post-dispersal seed consumption primarily removes seeds that would otherwise never contribute to the population\\u000a and granivory has minimal impacts on plant

John L. Maron; Ellen L. Simms

1997-01-01

193

Reconciling Seed Dispersal and Seed Bank Observations to Predict Smooth Brome  

E-print Network

Reconciling Seed Dispersal and Seed Bank Observations to Predict Smooth Brome (Bromus inermis for their establishment. Nomenclature: Smooth brome, Bromus inermis Leyss. Key words: Biological invasions, plant

Kenkel, Norm

194

Effect of Resting Patterns of Tamarins (Saguinus fuscicollis and Saguinus mystax) on the Spatial Distribution of Seeds and Seedling Recruitment.  

PubMed

The spatial distributions of dispersed seeds have important evolutionary consequences for plants. Repeated defecations in sites frequently used by seed dispersers can result in high seed concentrations. We observed the resting behavior of a mixed-species group of tamarins in Peru and recorded the occurrence of seed dispersal (over 8 mo) and seed fate (over 11-22 mo) to determine whether the location and use of resting sites influenced the spatial distribution of dispersed seeds and seedlings. The tamarins rested mostly on trees (Saguinus fuscicollis: 60.6%, S. mystax: 89.2%) and dead trunks (S. fuscicollis: 24.4%) and used 61% of their resting sites repeatedly. During both the dry and wet seasons, tamarins dispersed significantly more seeds within resting areas (0.00662 and 0.00424 seeds/m(2), respectively) than outside them (0.00141 and 0.00181 seeds/m(2)). Seed survival and seedling recruitment did not differ significantly between resting and other areas, resulting in a higher seedling concentration around the resting sites. Seed density did not increase with the duration or the frequency of use of the resting sites but did increase when we pooled the seasonal resting sites together in 50 m?×?50 m quadrats, ultimately causing a clumped distribution of dispersed seeds. The use of resting sites in secondary forest, particularly during the dry season, allows the creation of seedling recruitment centers for species coming from the primary forest. Our findings show that tamarin resting behavior affects the spatial distribution of dispersed seeds and seedlings, and their resting sites play an important role in plant diversity maintenance and facilitate forest regeneration in degraded areas. PMID:21423318

Muñoz Lazo, Fernando Julio João; Culot, Laurence; Huynen, Marie-Claude; Heymann, Eckhard W

2011-02-01

195

Functional importance of avian seed dispersers changes in response to human-induced forest edges in tropical seed-dispersal networks.  

PubMed

Although seed-dispersal networks are increasingly used to infer the functioning of ecosystems, few studies have investigated the link between the properties of these networks and the ecosystem function of seed dispersal by animals. We investigate how frugivore communities and seed dispersal change with habitat disturbance and test whether relationships between morphological traits and functional roles of seed dispersers change in response to human-induced forest edges. We recorded interaction frequencies between fleshy fruited plants and frugivorous bird species in tropical montane forests in the Bolivian Andes and recorded functional bird traits (body mass, gape width and wing tip length) associated with quantitative (seed-removal rate) and qualitative (seed-deposition pattern) components of seed-dispersal effectiveness. We found that the abundance and richness of frugivorous birds were higher at forest edges. More fruits were removed and dispersed seeds were less clustered at edges than in the interior. Additionally, functional and interaction diversity were higher at edges than in the interior, but functional and interaction evenness did not differ. Interaction strength of bird species increased with body mass, gape width and wing tip length in the forest interior, but was not related to bird morphologies at forest edges. Our study suggests that increases in functional and interaction diversity and an even distribution of interaction strength across bird morphologies lead to enhanced quantity and tentatively enhanced quality of seed dispersal. It also suggests that the effects of species traits on ecosystem functions can vary along small-scale gradients of human disturbance. PMID:25182931

Saavedra, Francisco; Hensen, Isabell; Beck, Stephan G; Böhning-Gaese, Katrin; Lippok, Denis; Töpfer, Till; Schleuning, Matthias

2014-11-01

196

Seed Mucilage Improves Seedling Emergence of a Sand Desert Shrub  

PubMed Central

The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed mucilage enhances seedling emergence in a low precipitation regime and under conditions of sand burial. In a greenhouse experiment, two types of Artemisia sphaerocephala achenes (intact and demucilaged) were exposed to different combinations of burial depth (0, 5, 10, 20, 40 and 60 mm) and irrigation regimes (low, medium and high, which simulated the precipitation amount and frequency in May, June and July in the natural habitat, respectively). Seedling emergence increased with increasing irrigation. It was highest at 5 mm sand burial depth and ceased at burial depths greater than 20 mm in all irrigation regimes. Mucilage significantly enhanced seedling emergence at 0, 5 and 10 mm burial depths in low irrigation, at 0 and 5 mm burial depths in medium irrigation and at 0 and 10 mm burial depths in high irrigation. Seed mucilage also reduced seedling mortality at the shallow sand burial depths. Moreover, mucilage significantly affected seedling emergence time and quiescence and dormancy percentages. Our findings suggest that seed mucilage plays an ecologically important role in successful seedling establishment of A. sphaerocephala by improving seedling emergence and reducing seedling mortality in stressful habitats of the sandy desert environment. PMID:22511952

Yang, Xuejun; Baskin, Carol C.; Baskin, Jerry M.; Liu, Guangzheng; Huang, Zhenying

2012-01-01

197

Unique Method for Generating Design Earthquake Time History Seeds  

SciTech Connect

A method has been developed which takes a single seed earthquake time history and produces multiple similar seed earthquake time histories. These new time histories possess important frequency and cumulative energy attributes of the original while having a correlation less than 30% (per the ASCE/SEI 43-05 Section 2.4 [1]). They are produced by taking the fast Fourier transform of the original seed. The averaged amplitudes are then pared with random phase angles and the inverse fast Fourier transform is taken to produce a new time history. The average amplitude through time is then adjusted to encourage a similar cumulative energy curve. Next, the displacement is modified to approximate the original curve using Fourier techniques. Finally, the correlation is checked to ensure it is less than 30%. This process does not guarantee that the correlation will be less than 30% for all of a given set of new curves. It does provide a simple tool where a few additional iterations of the process should produce a set of seed earthquake time histories meeting the correlation criteria.

R. E. Spears

2008-07-01

198

Laser Phase Errors in Seeded FELs  

SciTech Connect

Harmonic seeding of free electron lasers has attracted significant attention from the promise of transform-limited pulses in the soft X-ray region. Harmonic multiplication schemes extend seeding to shorter wavelengths, but also amplify the spectral phase errors of the initial seed laser, and may degrade the pulse quality. In this paper we consider the effect of seed laser phase errors in high gain harmonic generation and echo-enabled harmonic generation. We use simulations to confirm analytical results for the case of linearly chirped seed lasers, and extend the results for arbitrary seed laser envelope and phase.

Ratner, D.; Fry, A.; Stupakov, G.; White, W.; /SLAC

2012-03-28

199

Detection algorithm for multiple rice seeds images  

NASA Astrophysics Data System (ADS)

The objective of this research is to develop a digital image analysis algorithm for detection of multiple rice seeds images. The rice seeds used for this study involved a hybrid rice seed variety. Images of multiple rice seeds were acquired with a machine vision system for quality inspection of bulk rice seeds, which is designed to inspect rice seeds on a rotating disk with a CCD camera. Combining morphological operations and parallel processing gave improvements in accuracy, and a reduction in computation time. Using image features selected based on classification ability; a highly acceptable defects classification was achieved when the algorithm was implemented for all the samples to test the adaptability.

Cheng, F.; Ying, Y. B.

2006-10-01

200

Soil warming increases plant species richness but decreases germination from the alpine soil seed bank.  

PubMed

Global warming is occurring more rapidly above the treeline than at lower elevations and alpine areas are predicted to experience above average warming in the future. Temperature is a primary factor in stimulating seed germination and regulating changes in seed dormancy status. Thus, plant regeneration from seed will be crucial to the persistence, migration and post disturbance recruitment of alpine plants in future climates. Here, we present the first assessment of the impact of soil warming on germination from the persistent alpine soil seed bank. Contrary to expectations, soil warming lead to reduced overall germination from the soil seed bank. However, germination response to soil temperature was species specific such that total species richness actually increased by nine with soil warming. We further explored the system by assessing the prevalence of seed dormancy and germination response to soil disturbance, the frequency of which is predicted to increase under climate change. Seeds of a significant proportion of species demonstrated physiological dormancy mechanisms and germination of several species appeared to be intrinsically linked to soil disturbance. In addition, we found no evidence of subalpine species and little evidence of exotic weed species in the soil, suggesting that the soil seed bank will not facilitate their invasion of the alpine zone. In conclusion, changes in recruitment via the alpine soil seed bank can be expected under climate change, as a result of altered dormancy alleviation and germination cues. Furthermore, the alpine soil seed bank, and the species richness therein, has the potential to help maintain local species diversity, support species range shift and moderate species dominance. Implications for alpine management and areas for further study are also discussed. PMID:23505066

Hoyle, Gemma L; Venn, Susanna E; Steadman, Kathryn J; Good, Roger B; McAuliffe, Edward J; Williams, Emlyn R; Nicotra, Adrienne B

2013-05-01

201

CT, MR, and ultrasound image artifacts from prostate brachytherapy seed implants: The impact of seed size  

SciTech Connect

Purpose: To investigate the effects of brachytherapy seed size on the quality of x-ray computed tomography (CT), ultrasound (US), and magnetic resonance (MR) images and seed localization through comparison of the 6711 and 9011 {sup 125}I sources. Methods: For CT images, an acrylic phantom mimicking a clinical implantation plan and embedded with low contrast regions of interest (ROIs) was designed for both the 0.774 mm diameter 6711 (standard) and the 0.508 mm diameter 9011 (thin) seed models (Oncura, Inc., and GE Healthcare, Arlington Heights, IL). Image quality metrics were assessed using the standard deviation of ROIs between the seeds and the contrast to noise ratio (CNR) within the low contrast ROIs. For US images, water phantoms with both single and multiseed arrangements were constructed for both seed sizes. For MR images, both seeds were implanted into a porcine gel and imaged with pelvic imaging protocols. The standard deviation of ROIs and CNR values were used as metrics of artifact quantification. Seed localization within the CT images was assessed using the automated seed finder in a commercial brachytherapy treatment planning system. The number of erroneous seed placements and the average and maximum error in seed placements were recorded as metrics of the localization accuracy. Results: With the thin seeds, CT image noise was reduced from 48.5 {+-} 0.2 to 32.0 {+-} 0.2 HU and CNR improved by a median value of 74% when compared with the standard seeds. Ultrasound image noise was measured at 50.3 {+-} 17.1 dB for the thin seed images and 50.0 {+-} 19.8 dB for the standard seed images, and artifacts directly behind the seeds were smaller and less prominent with the thin seed model. For MR images, CNR of the standard seeds reduced on average 17% when using the thin seeds for all different imaging sequences and seed orientations, but these differences are not appreciable. Automated seed localization required an average ({+-}SD) of 7.0 {+-} 3.5 manual corrections in seed positions for the thin seed scans and 3.0 {+-} 1.2 manual corrections in seed positions for the standard seed scans. The average error in seed placement was 1.2 mm for both seed types and the maximum error in seed placement was 2.1 mm for the thin seed scans and 1.8 mm for the standard seed scans. Conclusions: The 9011 thin seeds yielded significantly improved image quality for CT and US images but no significant differences in MR image quality.

Robertson, Andrew K. H.; Basran, Parminder S.; Thomas, Steven D.; Wells, Derek [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada); Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada) and Department of Medical Physics, British Columbia Cancer Agency-Vancouver Island Cancer Centre, Victoria, British Columbia V8R 6V5 (Canada); Department of Medical Physics, British Columbia Cancer Agency-Fraser Valley Cancer Centre, Victoria, British Columbia V3V 1Z2 (Canada); Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada) and Department of Medical Physics, British Columbia Cancer Agency-Vancouver Island Cancer Centre, Victoria, British Columbia V8R 6V5 (Canada)

2012-04-15

202

Seeding Considerations in Restoring Big Sagebrush Habitat  

E-print Network

Abstract-This papcrdescribes methods of managing or seeding to restore big sagebrush communities for wildlife habitat. The focus is on three bigsagebrush subspecies, Wyomingbigsagebrush (Artemisia tridentata ssp. wyomingensis), basin big sagebrush (Artemisia tridentata ssp. tridentata), and mountain big sagebrush (Artemisia tridentata ssp. vaseyana). Natural colonization of the native plant community may be the preferred management action on sites where native seed sources are available to successfully reestablish the desired wildlife habitat. On highly disturbed or otherwise damaged sites and where competition from weeds is excessive, seeding,,~II be utilized to restore big sagebrush for wildlife habitat. Big sagebrush seed is never seeded alone in site rehabilitation and restoration projects. The best time to seed or interseed big sagebrush seed mixes, including grasses and forbs, is in late fall or early winter. The overall best method to reestablish big sagebrush is to use a rangeland drill at a shallow setting following site preparation, including tillage and weed control. When big sagebrush is drill seeded mth other seed types, it is recommended that it be seeded through a separate drill box to permit very shallow seeding and proper seed placement for plant establishment. Seedings of native plants, including big sagebrush, should be protected from grazing for at least 3 to 5 years to allow time for the shrubs and forbs to become established.

Scott M. Lambert

203

Seed Germination in Chenopodium album L  

PubMed Central

Effects of ethylene, gibberellins, and kinetin on the germination of two lots of Chenopodium album L. seeds, collected from the field in 1982 and 1983, were studied in relation to the availability of nitrate. The experiments were conducted in darkness and at temperatures ranging from 12 to 32°C. Ethylene induced over 75% germination in the 1983 seed but had little effect on the 1982 seed. Nitrate was only slightly promotive in either of the two seed lots. A combination of ethylene and nitrate, however, acted synergistically on 1982 seed, resulting in as much germination as that induced in 1983 seed by ethylene alone. In 1983 seed, a combination of ethylene and nitrate was only marginally more effective than ethylene. A similar relationship was observed in the effects of gibberellic acid4+7 (GA4+7) and nitrate on seeds from the two lots. The 1982 seed, which responded synergistically to combinations of nitrate with ethylene or GA4+7 was found to contain an extremely low endogenous level of nitrate as compared to 1983 seed. Thus, high levels of either endogenous or applied nitrate appeared to enhance the germination response to ethylene or GA4+7. Kinetin had no effect on 1982 seed and only a small promotive effect on 1983 seed. There was no synergism between kinetin and nitrate in either of the seed lots. PMID:16664167

Saini, Hargurdeep S.; Bassi, Pawan K.; Spencer, Mary S.

1985-01-01

204

Generation of fs laser pulses from a ps pulse-pumped optical parametric amplifier with a beat-wave seed signal  

E-print Network

Generation of fs laser pulses from a ps pulse-pumped optical parametric amplifier with a beat-wave that 250-fs laser pulses at 1.55 lm are generated from a beat-wave seeded optical parametric amplifier a beat-wave seeding scheme for generating fs frequency-down-converted laser pulses from a ps pulse

205

Age and size effects on seed productivity of northern black spruce Jayme N. Viglas, Carissa D. Brown, and Jill F. Johnstone  

E-print Network

ARTICLE Age and size effects on seed productivity of northern black spruce Jayme N. Viglas, Carissa frequency. Here, we examine the relationship between stand age and seed productivity of black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) in Yukon Territory and Alaska. Black spruce trees were aged

Ickert-Bond, Steffi

206

7 CFR 201.54 - Number of seeds for germination.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Number of seeds for germination. 201.54 Section... § 201.54 Number of seeds for germination. At least 400 seeds...be added to the regular germination tolerances. The seeds shall be tested in...

2011-01-01

207

7 CFR 201.54 - Number of seeds for germination.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Number of seeds for germination. 201.54 Section... § 201.54 Number of seeds for germination. At least 400 seeds...be added to the regular germination tolerances. The seeds shall be tested in...

2012-01-01

208

7 CFR 201.54 - Number of seeds for germination.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 false Number of seeds for germination. 201.54 Section... § 201.54 Number of seeds for germination. At least 400 seeds...be added to the regular germination tolerances. The seeds shall be tested in...

2014-01-01

209

7 CFR 201.54 - Number of seeds for germination.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Number of seeds for germination. 201.54 Section... § 201.54 Number of seeds for germination. At least 400 seeds...be added to the regular germination tolerances. The seeds shall be tested in...

2013-01-01

210

7 CFR 201.64 - Pure live seed.  

Code of Federal Regulations, 2011 CFR

...REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed. [5 FR 35,...

2011-01-01

211

7 CFR 201.64 - Pure live seed.  

Code of Federal Regulations, 2014 CFR

...REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed. [5 FR 35,...

2014-01-01

212

7 CFR 201.64 - Pure live seed.  

Code of Federal Regulations, 2012 CFR

...REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed. [5 FR 35,...

2012-01-01

213

7 CFR 201.64 - Pure live seed.  

Code of Federal Regulations, 2013 CFR

...REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed. [5 FR 35,...

2013-01-01

214

Seed composition, seedling emergence and early seeding vigour of red kidney bean seed produced at elevated temperature and Carbon dioxide  

Technology Transfer Automated Retrieval System (TEKTRAN)

Understanding effects of temperature and carbon dioxide (CO2) on seed quality is important under present and future climates. The objective was to determine the effects of elevated growth temperature and CO2 during seed-filling of parent plants on seed composition and ensuing seedling emergence and ...

215

Recommended Amounts of Nuts, seeds, and soy  

Cancer.gov

Recommended Amounts of Nuts, seeds, and soy Table B14. Nuts, seeds, and soy: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) %

216

Global analysis of gene activity during Arabidopsis seed development and identification of seed-specific  

E-print Network

Global analysis of gene activity during Arabidopsis seed development and identification of seed, including those unique to seeds, we used Affymetrix GeneChips to profile Arabidopsis genes active in seeds.Seedgenesetswerecomparedwiththoseexpressedin prefertilization ovules, germinating seedlings, and leaves, roots, stems, and floral buds of the mature plant. Most

Goldberg, Robert B.

217

Seed Disperser Effectiveness: The Quantity Component and Patterns of Seed Rain for Prunus mahaleb  

Microsoft Academic Search

In this paper we analyze the seed dispersal stage of the Prunus mahaleb-frugivorous bird inter- action from fruit removal through seed delivery within the context of disperser effectiveness. The effectiveness of a frugivorous species as a seed disperser is the contribution it makes to plant fitness. Effectiveness depends on the quantity of seed dispersed (''quantity component'') and the quality of

Pedro Jordano; Eugene W. Schupp

2000-01-01

218

ORIGINAL PAPER Internal dispersal of seeds by waterfowl: effect of seed size  

E-print Network

and germination of ingested seeds). A combination of experiments with captive waterbirds and aquatic plant seeds and the percent germination and germination rates of seeds. Among the three Scirpus species used, those) survived ingestion. Retention time affected the percent germination and germination rate of Scirpus seeds

Green, Andy J.

219

Evaluation of antioxidant and antiradical properties of Pomegranate (Punica granatum L.) seed and defatted seed extracts.  

PubMed

Pomegranate seeds are byproducts of the Pomegranate juice industries that contains functional compounds such as phenols. This study was aimed to evaluate the effect of solvents on extraction from Pomegranate seed and Pomegranate defatted seed and to measure the yield extract and phenolic content and antioxidant properties. For this purpose, the seeds and defatted seeds were directly isolated from fruits and seeds by cold pressing respectively, then were crushed and extracted with different solvents, including water, Methanol, Acetone, Ethyl acetate and Hexane and finally the extracts of them were evaluted. Phenolic compounds, ferric reducing-antioxidant power and radicals scavenging property of extracts were measured. The results showed the highest extraction efficiencies were for Hexane and Acetone solvents in extraction of seed and defatted seed respectively. The highest phenolic content was obtained from Methanol seed extract. Reducing activity test proved that the Methanol extracts of Pomegranate seed and Pomegranate defatted seed had the highest reducing strength. Results of radical scavenging activity were similar to reducing activity results. The order of antioxidant capacity of Pomegranate seed and Pomegranate defatted seed were found to be Methanol > Water > Acetone > Butanol > Ethyl acetate > Hexane. It can be concluded Pomegranate seed, which possesses high levels of polyphenols, can be one of the sources of the natural antioxidants. The Methanol extract had a higher antioxidant efficiency than seed and defatted seed extracts. PMID:25694727

Basiri, Shadi

2015-02-01

220

PRESSURIZED FLUID EXTRACTION OF PUMPKIN SEED AND PUMPKIN SEED PRESSED CAKE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pumpkin seed oil is one of the top three nutritional oils (hemp seed oil, flax seed oil, pumpkin seed oil) that provide the highest essential fatty acids (Omega 3 and Omega 6) required for healthy mind/body functioning. It is known to prevent and alleviate bladder and prostate problems. The oil th...

221

Automated seed detection and 3D reconstruction I: Seed Localization from Fluoroscopic Images or Radiographs.  

E-print Network

or Radiographs. Dragan Tubic 1,2 , André Zaccarin3 , Jean Pouliot1,4 , Luc Beaulieu1,4 1 Department of radiation of radioactive seeds on fluoroscopic images or scanned radiographs is presented. The extracted positions of seed of projections of seeds taken from different perspectives. To provide those projections the seed centers have

Pouliot, Jean

222

Diversity of plant oil seed-associated fungi isolated from seven oil-bearing seeds and their potential for the production of lipolytic enzymes.  

PubMed

Commercial oil-yielding seeds (castor, coconut, neem, peanut, pongamia, rubber and sesame) were collected from different places in the state of Tamil Nadu (India) from which 1279 endophytic fungi were isolated. The oil-bearing seeds exhibited rich fungal diversity. High Shannon-Index H' was observed with pongamia seeds (2.847) while a low Index occurred for coconut kernel-associated mycoflora (1.018). Maximum Colonization Frequency (%) was observed for Lasiodiplodia theobromae (176). Dominance Index (expressed in terms of the Simpson's Index D) was high (0.581) for coconut kernel-associated fungi, and low for pongamia seed-borne fungi. Species Richness (Chao) of the fungal isolates was high (47.09) in the case of neem seeds, and low (16.6) for peanut seeds. All 1279 fungal isolates were screened for lipolytic activity employing a zymogram method using Tween-20 in agar. Forty isolates showed strong lipolytic activity, and were morphologically identified as belonging to 19 taxa (Alternaria, Aspergillus, Chalaropsis, Cladosporium, Colletotrichum, Curvularia, Drechslera, Fusarium, Lasiodiplodia, Mucor, Penicillium, Pestalotiopsis, Phoma, Phomopsis, Phyllosticta, Rhizopus, Sclerotinia, Stachybotrys and Trichoderma). These isolates also exhibited amylolytic, proteolytic and cellulolytic activities. Five fungal isolates (Aspergillus niger, Chalaropsis thielavioides, Colletotrichum gloeosporioides, Lasiodiplodia theobromae and Phoma glomerata) exhibited highest lipase activities, and the best producer was Lasiodiplodia theobromae (108 U/mL), which was characterized by genomic sequence analysis of the ITS region of 18S rDNA. PMID:22806781

Venkatesagowda, Balaji; Ponugupaty, Ebenezer; Barbosa, Aneli M; Dekker, Robert F H

2012-01-01

223

Genetics of seed transmission Soybean mosaic virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soybean mosaic virus (SMV) is an aphid- and seed-transmitted member of the Potyviridae that infects soybean plants and, in years when virus infections are widespread, can cause significant reductions in the quantity and quality of seed harvested. Because seed-borne infections are the primary sources...

224

Plant Populations and Seeding Rates for Soybeans  

E-print Network

Plant Populations and Seeding Rates for Soybeans Andrew P. Robinson Department of Agronomy www input costs for soybean growers, so it's important for growers to plant the right amount of seed to minimize input costs and increase profitability. Seeding rate, plant population, and row spacing are tied

Holland, Jeffrey

225

Seed dispersal in Erythronium grandiflorum (Liliaceae)  

Microsoft Academic Search

Primary and secondary seed dispersal was investigated for the glacier lily Erythronium grandiflorum in the Colorado Rocky Mountains. These heavy seeds have no obvious adaptations for biotic or abiotic dispersal, but can be thrown short distances when the dehiscent fruits are shaken by wind. We used sticky traps to measure primary transport of seeds up to 1 m away from

George D. Weiblen; James D. Thomson

1995-01-01

226

TRIACYLGLYCEROL PHASE AND SEED STORAGE BEHAVIOR  

Technology Transfer Automated Retrieval System (TEKTRAN)

Anecdotal stories have long suggested that oil-rich seeds store poorly; however, laboratory studies show that lipid content does not correlate with seed quality. Recently, we found that the tendency of triacylglycerols (TAG) to crystallize during storage of Cuphea seeds has a profound effect on see...

227

Forward genetics studies of seed phytic acid  

Technology Transfer Automated Retrieval System (TEKTRAN)

Both the chemical composition and total amount of seed phosphorus (P) are important to the end-use quality of cereal and legume seed crops. The chemistry of seed total P largely revolves around the synthesis and storage of phytic acid (myo-inositol hexaphosphate). Forward genetics research, beginnin...

228

7 CFR 201.57 - Hard seeds.  

Code of Federal Regulations, 2010 CFR

... 3 2010-01-01 2010-01-01 false Hard seeds. 201.57 Section 201.57 Agriculture...Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at the end of the prescribed test because they...

2010-01-01

229

Formative Assessment Probes: Seeds in a Bag  

ERIC Educational Resources Information Center

Many young children come to school with prior experiences planting seeds in a garden or in a pot, watering them, and seeing them grow. These early scientific investigations are designed to help children understand that seeds need water, something to grow in (such as soil), and the right temperature to sprout--if these conditions are met, a seed

Keeley, Page

2014-01-01

230

7 CFR 201.21 - Hard seed.  

Code of Federal Regulations, 2013 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [24 FR 3953, May 15,...

2013-01-01

231

7 CFR 201.30 - Hard seed.  

Code of Federal Regulations, 2013 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [32 FR 12779, Sept. 6,...

2013-01-01

232

7 CFR 201.30 - Hard seed.  

Code of Federal Regulations, 2014 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [32 FR 12779, Sept. 6,...

2014-01-01

233

7 CFR 201.21 - Hard seed.  

Code of Federal Regulations, 2012 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [24 FR 3953, May 15,...

2012-01-01

234

7 CFR 201.21 - Hard seed.  

Code of Federal Regulations, 2014 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [24 FR 3953, May 15,...

2014-01-01

235

7 CFR 201.30 - Hard seed.  

Code of Federal Regulations, 2012 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [32 FR 12779, Sept. 6,...

2012-01-01

236

7 CFR 201.21 - Hard seed.  

Code of Federal Regulations, 2011 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [24 FR 3953, May 15,...

2011-01-01

237

7 CFR 201.30 - Hard seed.  

Code of Federal Regulations, 2011 CFR

...percentage of hard seed, if any is present, for any seed required to be labeled as to the percentage of germination, and the percentage of hard seed shall not be included as part of the germination percentage. [32 FR 12779, Sept. 6,...

2011-01-01

238

TAPPING INTO THE PASTURE SEED BANK  

Technology Transfer Automated Retrieval System (TEKTRAN)

The plant species found in pasture soil seed banks fall into four main categories. The first type of seed bank is short-term (usually less than one year) formed from plants that shed seed in the summer, germinate in the fall, and grow mainly in the early spring of the following year. These plants fi...

239

Breaking of Seed Dormancy by Catalase Inhibition  

Microsoft Academic Search

Germination of some dormant seeds is promoted by solutions of thiourea, sodium nitrite, and hydroxylamine salts. The promotions are accompanied by irreversible inhibition of catalase (EC 1.11.1.6) in extracts from the seeds. The seeds are also promoted in germination by catechol and pyrogallol solutions. These effects are recorded for lettuce (Lactuca sativa L. cv. Grand Rapids) and pigweed (Amaranthus albus

S. B. Hendricks; R. B. Taylorson

1975-01-01

240

Extraction and Analysis of Tomato Seed Oil  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tomato seeds represent a very large waste by-product from the processing of tomatoes into products such as tomato juice, sauce and paste. One potential use for these seeds is as a source of vegetable oil. This research investigated the oil content of tomato seeds using several extraction technique...

241

7 CFR 946.12 - Seed potatoes.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Seed potatoes. 946.12 Section 946.12 Agriculture...DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN WASHINGTON Order Regulating Handling Definitions § 946.12 Seed potatoes. Seed potatoes means and...

2010-01-01

242

7 CFR 947.12 - Seed potatoes.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Seed potatoes. 947.12 Section 947.12 Agriculture...DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN MODOC AND SISKIYOU COUNTIES...Handling Definitions § 947.12 Seed potatoes. Seed potatoes means and...

2010-01-01

243

Frequency domain optical parametric amplification  

PubMed Central

Today’s ultrafast lasers operate at the physical limits of optical materials to reach extreme performances. Amplification of single-cycle laser pulses with their corresponding octave-spanning spectra still remains a formidable challenge since the universal dilemma of gain narrowing sets limits for both real level pumped amplifiers as well as parametric amplifiers. We demonstrate that employing parametric amplification in the frequency domain rather than in time domain opens up new design opportunities for ultrafast laser science, with the potential to generate single-cycle multi-terawatt pulses. Fundamental restrictions arising from phase mismatch and damage threshold of nonlinear laser crystals are not only circumvented but also exploited to produce a synergy between increased seed spectrum and increased pump energy. This concept was successfully demonstrated by generating carrier envelope phase stable, 1.43?mJ two-cycle pulses at 1.8??m wavelength. PMID:24805968

Schmidt, Bruno E.; Thiré, Nicolas; Boivin, Maxime; Laramée, Antoine; Poitras, François; Lebrun, Guy; Ozaki, Tsuneyuki; Ibrahim, Heide; Légaré, François

2014-01-01

244

Reversible Seeding in Storage Rings  

SciTech Connect

We propose to generate steady-state microbunching in a storage ring with a reversible seeding scheme. High gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are two promising methods for microbunching linac electron beams. Because both schemes increase the energy spread of the seeded beam, they cannot drive a coherent radiator turn-by-turn in a storage ring. However, reversing the seeding process following the radiator minimizes the impact on the electron beam and may allow coherent radiation at or near the storage ring repetition rate. In this paper we describe the general idea and outline a proof-of-principle experiment. Electron storage rings can drive high average power light sources, and free-electron lasers (FELs) are now producing coherent light sources of unprecedented peak brightness While there is active research towards high repetition rate FELs (for example, using energy recovery linacs), at present there are still no convenient accelerator-based sources of high repetition rate, coherent radiation. As an alternative avenue, we recently proposed to establish steady-state microbunching (SSMB) in a storage ring. By maintaining steady-state coherent microbunching at one point in the storage ring, the beam generates coherent radiation at or close to the repetition rate of the storage ring. In this paper, we propose a method of generating a microbunched beam in a storage ring by using reversible versions of linac seeding schemes.

Ratner, Daniel; Chao, Alex; /SLAC

2011-12-14

245

Sowing the Seeds of Neuroscience  

NSDL National Science Digital Library

Sowing the Seeds of Neuroscience seeks to increase student interest and understanding of neuroscience through simple, safe lab investigations using plants. The site contains 8 laboratory investigations exploring properties of compounds found in plants and their effect on the behavior and growth of invertebrates. The site also provides general neuroscience and medicinal plant information.

Dr. Eric Chudler

2014-04-04

246

Seed microRNA Research  

Technology Transfer Automated Retrieval System (TEKTRAN)

MicroRNAs (miRNAs) are key regulatory molecules that play critical roles in gene expression. The biological functions of miRNAs are important for developmental processes in plants and animals. Little is known about the functions of miRNAs in seeds. To gain a better understand-ing of the regulation o...

247

Climate Kids: Make Seed Paper  

NSDL National Science Digital Library

The recycled paper produced from the instructions provided contains an additional component - wildflower seeds. The entire paper disc can be planted; the sprouting of the flowers can be observed and analyzed. The Climate Kids website is a NASA education resource featuring articles, videos, images and games focused on the science of climate change.

2013-12-03

248

SEED BIOLOGY OF MEDICAGO TRUNCATULA  

Technology Transfer Automated Retrieval System (TEKTRAN)

The seed of Medicago truncatula have morphological features typical of dicotyledons, and are borne in a spine-covered spiral pod. The cotyledons are rich in protein (35-45%), the major storage molecule. They accumulate approximately 10% lipids and only traces of starch. The most abundant proteins a...

249

The rice direct-seeding system using multiple seed pellets in northern Tohoku  

Microsoft Academic Search

In Japan, direct-seeding methods of rice are now being intro- duced to lower rice production costs. However, in the north- east area, direct seeding did not spread easily. Under chilly spring weather conditions, seed establishment in direct seed- ing was unstable in wet-seeded fields. Also, growth of broad- cast rice is difficult to control. Moreover, good-tasting variet- ies, such as

Hiroyuki Sekiya; Hitoshi Ogiwara; Shoichi Kimura; Ryuji Otani; Yukio Yaji; Satoshi Morita; Tatsushi Togashi; Hiroaki Watanabe

250

Reducing seed damage by soybean bugs by growing small-seeded soybeans and delaying sowing time  

Microsoft Academic Search

We evaluated the effects of seed size and planting time on seed damage by soybean bugs in the field over 2 years. Kyushu-143, a small-seeded soybean with many pods, suffered less damage at harvest by soybean bugs than the large-seeded cultivars Fukuyutaka and Sachiyutaka. We attributed the field tolerance of Kyushu-143 to large numbers of “spare” seeds that could compensate

Takashi Wada; Nobuyuki Endo; Masakazu Takahashi

2006-01-01

251

Two-phase seed dispersal: linking the effects of frugivorous birds and seed-caching rodents  

Microsoft Academic Search

Frugivorous birds disperse the seeds of many fruit-bearing plants, but the fate of seeds after defecation or regurgitation\\u000a is often unknown. Some rodents gather and scatter hoard seeds, and some of these may be overlooked, germinate, and establish\\u000a plants. We show that these two disparate modes of seed dispersal are linked in some plants. Rodents removed large (>25 mg)\\u000a seeds from

Stephen B. Vander Wall; Kellie M. Kuhn; Jennifer R. Gworek

2005-01-01

252

Self-seeding ring optical parametric oscillator  

DOEpatents

An optical parametric oscillator apparatus utilizing self-seeding with an external nanosecond-duration pump source to generate a seed pulse resulting in increased conversion efficiency. An optical parametric oscillator with a ring configuration are combined with a pump that injection seeds the optical parametric oscillator with a nanosecond duration, mJ pulse in the reverse direction as the main pulse. A retroreflecting means outside the cavity injects the seed pulse back into the cavity in the direction of the main pulse to seed the main pulse, resulting in higher conversion efficiency.

Smith, Arlee V. (Albuquerque, NM); Armstrong, Darrell J. (Albuquerque, NM)

2005-12-27

253

Natural variation for seed longevity and seed dormancy are negatively correlated in Arabidopsis.  

PubMed

Dormancy is a state of metabolic arrest that facilitates the survival of organisms during environmental conditions incompatible with their regular course of life. Many organisms have deep dormant stages to promote an extended life span (increased longevity). In contrast, plants have seed dormancy and seed longevity described as two traits. Seed dormancy is defined as a temporary failure of a viable seed to germinate in conditions that favor germination, whereas seed longevity is defined as seed viability after dry storage (storability). In plants, the association of seed longevity with seed dormancy has not been studied in detail. This is surprising given the ecological, agronomical, and economic importance of seed longevity. We studied seed longevity to reveal its genetic regulators and its association with seed dormancy in Arabidopsis (Arabidopsis thaliana). Integrated quantitative trait locus analyses for seed longevity, in six recombinant inbred line populations, revealed five loci: Germination Ability After Storage1 (GAAS1) to GAAS5. GAAS loci colocated with seed dormancy loci, Delay Of Germination (DOG), earlier identified in the same six recombinant inbred line populations. Both GAAS loci and their colocation with DOG loci were validated by near isogenic lines. A negative correlation was observed, deep seed dormancy correlating with low seed longevity and vice versa. Detailed analysis on the collocating GAAS5 and DOG1 quantitative trait loci revealed that the DOG1-Cape Verde Islands allele both reduces seed longevity and increases seed dormancy. To our knowledge, this study is the first to report a negative correlation between seed longevity and seed dormancy. PMID:23085841

Nguyen, Thu-Phuong; Keizer, Paul; van Eeuwijk, Fred; Smeekens, Sjef; Bentsink, Leónie

2012-12-01

254

Control of seed mass by APETALA2  

PubMed Central

Arabidopsis APETALA2 (AP2) encodes a member of the AP2/EREBP (ethylene responsive element binding protein) class of transcription factors and is involved in the specification of floral organ identity, establishment of floral meristem identity, suppression of floral meristem indeterminancy, and development of the ovule and seed coat. Here, we show that loss-of-function ap2 mutations cause an increase in seed mass relative to that of wild-type seeds. Analysis of an allelic series of ap2 mutations showed that increases in seed mass corresponded with the severity of defects in flower structure, indicating that AP2 activity directly influences seed mass. Experiments with male-sterile plants and deflowered wild-type plants showed that reduced fertility of ap2 mutant plants due to abnormal flower structure accounted for only part of the increase in seed mass caused by strong ap2 mutant alleles. Reciprocal cross experiments showed that AP2 acts maternally to control seed mass. The maternal effect of AP2 on seed mass involves the regulation of both embryo cell number and cell size. We show further that ap2 mutations cause changes in the ratio of hexose to sucrose during seed development, opening the possibility that AP2 may control seed mass through its effects on sugar metabolism. Together, these results identify a role for AP2 in controlling seed mass. PMID:15708976

Ohto, Masa-aki; Fischer, Robert L.; Goldberg, Robert B.; Nakamura, Kenzo; Harada, John J.

2005-01-01

255

Pod and seed mycoflora on transgenic and conventional soybean [Glycine max (L.) Merrill] cultivars in Mississippi.  

PubMed

A 2-year (1999-2000) study was conducted at Starkville and Stoneville, MS to determine if the occurrence of the mycoflora varied on Roundup Ready (transgenic) compared to conventional soybean (Glycine max) cultivars. A total of 7,658 fungal isolates were identified from the pod and seed tissues of four cultivars compared at growth stages R6 and R8. Ninety-nine percent of all fungi isolated were mitosporic fungi and ascomycetes. In both years, total fungal isolates from the two locations were greater from the pod (65%) than from seed (33%) tissues. Isolation frequency from conventional cultivars was 54% compared to 46% for the transgenic cultivars. The most common fungi identified that are reported pathogens of soybean included Alternaria, Cercospora, Cladosporium, Diaporthe, Fusarium and Verticillium spp. When main effects and interactions were compared among the frequency data for the fungal genera, significant differences occurred, but consistent trends were not noted. Isolation frequencies of Diaporthe spp. during the R6 growth stage, were significantly greater on the conventional than on the transgenic cultivars in both years of the study, but only at Starkville. Isolation frequencies from samples taken during the R8 growth stage were similar at both locations in 1999 and 2000. Fusarium spp. isolated at R6 and R8 growth stages from pod and seed tissues were significantly greater on conventional than on transgenic cultivars in 2000. Even though frequencies were often significantly different between the transgenic and conventional cultivars, the data was not consistent between locations, pod and seed tissues, or growth stages. The pod and seed mycoflora of transgenic and conventional soybean cultivars was, therefore, similar in Mississippi. PMID:15119858

Villarroel, D A; Baird, R E; Trevathan, L E; Watson, C E; Scruggs, M L

2004-02-01

256

Elemental Concentrations in the Seed of Mutants and Natural Variants of Arabidopsis thaliana Grown under Varying Soil Conditions  

PubMed Central

The concentrations of mineral nutrients in seeds are critical to both the life cycle of plants as well as human nutrition. These concentrations are strongly influenced by soil conditions, as shown here by quantifying the concentration of 14 elements in seeds from Arabidopsis thaliana plants grown under four different soil conditions: standard, or modified with NaCl, heavy metals, or alkali. Each of the modified soils resulted in a unique change to the seed ionome (the mineral nutrient content of the seeds). To help identify the genetic networks regulating the seed ionome, changes in elemental concentrations were evaluated using mutants corresponding to 760 genes as well as 10 naturally occurring accessions. The frequency of ionomic phenotypes supports an estimate that as much as 11% of the A. thaliana genome encodes proteins of functional relevance to ion homeostasis in seeds. A subset of mutants were analyzed with two independent alleles, providing five examples of genes important for regulation of the seed ionome: SOS2, ABH1, CCC, At3g14280 and CNGC2. In a comparison of nine different accessions to a Col-0 reference, eight accessions were observed to have reproducible differences in elemental concentrations, seven of which were dependent on specific soil conditions. These results indicate that the A. thaliana seed ionome is distinct from the vegetative ionome, and that elemental analysis is a sensitive approach to identify genes controlling ion homeostasis, including those that regulate gene expression, phospho-regulation, and ion transport. PMID:23671651

McDowell, Stephen C.; Akmakjian, Garo; Sladek, Chris; Mendoza-Cozatl, David; Morrissey, Joe B.; Saini, Nick; Mittler, Ron; Baxter, Ivan; Salt, David E.; Ward, John M.; Schroeder, Julian I.; Guerinot, Mary Lou; Harper, Jeffrey F.

2013-01-01

257

Vertical Bridgman growth of sapphire-Seed crystal shapes and seeding characteristics  

NASA Astrophysics Data System (ADS)

The growth of sapphire by the traditional vertical Bridgman (VB) method was studied by using various shapes of seed crystals and tungsten (W) crucibles shaped to match the seeds. Approximately 2-in. diameter, c-axis sapphire single crystals were reproducibly grown from three kinds of seed: thin, tapered and full diameter. Factors relating seed type to single-crystal growth are discussed, including the reproducibility of seeding processes, and the generation and elimination of low-angle grain boundaries (LAGBs). What was learned facilitated the subsequent growth of large-diameter, 3-, 4- and 6-in., c-axis single-crystal sapphires from full-diameter seeds.

Hoshikawa, K.; Osada, J.; Saitou, Y.; Ohba, E.; Miyagawa, C.; Kobayashi, T.; Yanagisawa, J.; Shinozuka, M.; Kanno, K.

2014-06-01

258

Compounds That Promote Seed Germination  

NSDL National Science Digital Library

The two molecules for this month come from the section Compound in Smoke Provides the Spark for Germination in the article about "Research Advances" by Angela G. King. These molecules have been demonstrated to stimulate seed germination under various conditions. The butenolide moiety is frequently encountered in natural products. An interesting approach to the synthesis of such molecules can be found in this Organic Letters article (accessed January 2005).

259

Generation of Particles and Seeding  

NASA Technical Reports Server (NTRS)

One of the most important elements in laser velocimetry, yet the most neglected, is the small particle embedded in the flow field that scatters the light necessary to make velocity measurements. An attempt to remove the confusion in choosing a seeding method by assessing many of the techniques currently used is presented. Their characteristics and typical limitations imposed by various applications are outlined. The ramifications of these methods on measurement accuracy are addressed.

Meyers, James F.

1991-01-01

260

Local Evolution of Seed Flotation in Arabidopsis  

PubMed Central

Arabidopsis seeds rapidly release hydrophilic polysaccharides from the seed coat on imbibition. These form a heavy mucilage layer around the seed that makes it sink in water. Fourteen natural Arabidopsis variants from central Asia and Scandinavia were identified with seeds that have modified mucilage release and float. Four of these have a novel mucilage phenotype with almost none of the released mucilage adhering to the seed and the absence of cellulose microfibrils. Mucilage release was modified in the variants by ten independent causal mutations in four different loci. Seven distinct mutations affected one locus, coding the MUM2 ?-D-galactosidase, and represent a striking example of allelic heterogeneity. The modification of mucilage release has thus evolved a number of times independently in two restricted geographical zones. All the natural mutants identified still accumulated mucilage polysaccharides in seed coat epidermal cells. Using nuclear magnetic resonance (NMR) relaxometry their production and retention was shown to reduce water mobility into internal seed tissues during imbibition, which would help to maintain seed buoyancy. Surprisingly, despite released mucilage being an excellent hydrogel it did not increase the rate of water uptake by internal seed tissues and is more likely to play a role in retaining water around the seed. PMID:24625826

Saez-Aguayo, Susana; Rondeau-Mouro, Corinne; Macquet, Audrey; Kronholm, Ilkka; Ralet, Marie-Christine; Berger, Adeline; Sallé, Christine; Poulain, Damien; Granier, Fabienne; Botran, Lucy; Loudet, Olivier; de Meaux, Juliette; Marion-Poll, Annie; North, Helen M.

2014-01-01

261

MHD seed recovery/regeneration  

NASA Astrophysics Data System (ADS)

Task 1 calls for the design, procurement, construction, and installation of the Seed Regeneration Proof-of-Concept Facility (SRPF) that will produce tonnage quantities of recyclable potassium formate seed at a design rate of 250 lb/hr for testing in the channel at the CDIF while collecting data that will be used to upgrade the design of a 300 MW(sub t) system. Approximately 12 tons of KCOOH (dry basis) as 70-75 wt percent solution were produced. The front end of the plant (potassium sulfate reaction and solids separation/washing units) was operated for five days in March. Most of the operations were conducted at a spent seed feed rate of 250 pounds/hour. A total of 8,500 gallons of dilute KCOOH solution was generated containing approximately 2.6 tons of potassium formate (dry basis). The average KCOOH content of this solution was 7 wt percent. The design KCOOH solution concentration for the front end of the plant is 8.5 wt percent. The evaporation unit was operated for a total of six days during March. Approximately 2.5 tons of potassium formate (dry basis) were processed through the evaporator and concentrated to greater then 7 wt percent.

262

Spectrally-resolved statistical characterization of seeded supercontinuum suppression using optical time-stretch.  

PubMed

Real-time experimental measurements of the spectrally-resolved noise properties of supercontinuum (SC) have been challenging because of the lack of ultrafast optical spectrometer technologies. Understanding the SC noise is increasingly important because it not only can gain new insight of the complex spectral dynamics of SC generation, but also provides clues to search for stable SC source. Driven by the intense interest in the active seeding mechanism for SC generation, we experimentally demonstrate real-time spectrally-resolved, broadband, statistical characterization of minute continuous-wave (CW) seeded SC, enabled by an ultrahigh-speed spectral acquisition technique called optical time-stretch (OTS). The shot-to-shot statistical analysis shows that the seeded SC exhibits a general compromise between SC bandwidth and spectral stability. OTS also allows us to experimentally identify the seeding condition for SC suppression, in which the spectral broadening is mainly contributed by the cascaded parametric process that delays Akhmediev Breather breakup process and subsequent soliton self-frequency shift. Additionally, the characteristic spectral signature of the Raman solitons, which are becalmed by the minute CW seed, can be clearly captured in real-time by OTS operated at a spectral acquisition rate as high as 20 MHz. We anticipate the OTS technique could provide further new insights for understanding more complex mechanisms of seeded-SC generation which can be examined experimentally. PMID:24921306

Ren, Zhibo; Xu, Yiqing; Qiu, Yi; Wong, Kenneth K Y; Tsia, Kevin

2014-05-19

263

Conflicting selection from fire and seed predation drives fine-scaled phenotypic variation in a widespread North American conifer.  

PubMed

Recent work has demonstrated that evolutionary processes shape ecological dynamics on relatively short timescales (eco-evolutionary dynamics), but demonstrating these effects at large spatial scales in natural landscapes has proven difficult. We used empirical studies and modeling to investigate how selective pressures from fire and predispersal seed predation affect the evolution of serotiny, an ecologically important trait. Serotiny is a highly heritable key reproductive trait in Rocky Mountain lodgepole pine (Pinus contorta subsp. latifolia), a conifer that dominates millions of hectares in western North America. In these forests, the frequency of serotiny determines postfire seedling density with corresponding community- and ecosystem-level effects. We found that serotinous individuals have a selective advantage at high fire frequencies and low predation pressure; however, very high seed predation shifted the selective advantage to nonserotinous individuals even at high fire frequencies. Simulation modeling suggests that spatial variation in the frequency of serotiny results from heterogeneity in these two selective agents. These results, combined with previous findings showing a negative association between the density of seed predators and the frequency of serotiny at both landscape and continental scales, demonstrate that contemporary patterns in serotiny reflect an evolutionary response to conflicting selection pressures from fire and seed predation. Thus, we show that variation in the frequency of a heritable polygenic trait depends on spatial variation in two dominant selective agents, and, importantly, the effects of the local trait variation propagate with profound consequences to the structure and function of communities and ecosystems across a large landscape. PMID:24979772

Talluto, Matthew V; Benkman, Craig W

2014-07-01

264

Conflicting selection from fire and seed predation drives fine-scaled phenotypic variation in a widespread North American conifer  

PubMed Central

Recent work has demonstrated that evolutionary processes shape ecological dynamics on relatively short timescales (eco-evolutionary dynamics), but demonstrating these effects at large spatial scales in natural landscapes has proven difficult. We used empirical studies and modeling to investigate how selective pressures from fire and predispersal seed predation affect the evolution of serotiny, an ecologically important trait. Serotiny is a highly heritable key reproductive trait in Rocky Mountain lodgepole pine (Pinus contorta subsp. latifolia), a conifer that dominates millions of hectares in western North America. In these forests, the frequency of serotiny determines postfire seedling density with corresponding community- and ecosystem-level effects. We found that serotinous individuals have a selective advantage at high fire frequencies and low predation pressure; however, very high seed predation shifted the selective advantage to nonserotinous individuals even at high fire frequencies. Simulation modeling suggests that spatial variation in the frequency of serotiny results from heterogeneity in these two selective agents. These results, combined with previous findings showing a negative association between the density of seed predators and the frequency of serotiny at both landscape and continental scales, demonstrate that contemporary patterns in serotiny reflect an evolutionary response to conflicting selection pressures from fire and seed predation. Thus, we show that variation in the frequency of a heritable polygenic trait depends on spatial variation in two dominant selective agents, and, importantly, the effects of the local trait variation propagate with profound consequences to the structure and function of communities and ecosystems across a large landscape. PMID:24979772

Talluto, Matthew V.; Benkman, Craig W.

2014-01-01

265

Effects of rodent species, seed species, and predator cues on seed fate  

NASA Astrophysics Data System (ADS)

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation dynamics. In a feeding arena, we tested whether rodent species, seed species, and indirect and direct predation cues influence seed selection and handling behaviors (e.g., scatter hoarding versus larder hoarding) of two heteromyid rodents, Ord's kangaroo rat ( Dipodomys ordii) and the Great Basin pocket mouse ( Perognathus parvus). The indirect cue was shrub cover, a feature of the environment. Direct cues, presented individually, were (1) control, (2) coyote ( Canis latrans) vocalization, (3) coyote scent, (4) red fox ( Vulpes vulpes) scent, or (5) short-eared owl ( Asio flammeus) vocalization. We offered seeds of three sizes: two native grasses, Indian ricegrass ( Achnatherum hymenoides) and bluebunch wheatgrass ( Pseudoroegneria spicata), and the non-native cereal rye ( Secale cereale), each in separate trays. Kangaroo rats preferentially harvested Indian ricegrass while pocket mice predominately harvested Indian ricegrass and cereal rye. Pocket mice were more likely to scatter hoard preferred seeds, whereas kangaroo rats mostly consumed and/or larder hoarded preferred seeds. No predator cue significantly affected seed preferences. However, both species altered seed handling behavior in response to direct predation cues by leaving more seeds available in the seed pool, though they responded to different predator cues. If these results translate to natural dynamics on the landscape, the two rodents are expected to have different impacts on seed survival and plant recruitment via their different seed selection and seed handling behaviors.

Sivy, Kelly J.; Ostoja, Steven M.; Schupp, Eugene W.; Durham, Susan

2011-07-01

266

Tannin concentration enhances seed caching by scatter-hoarding rodents: An experiment using artificial ‘seeds  

NASA Astrophysics Data System (ADS)

Tannins are very common among plant seeds but their effects on the fate of seeds, for example, via mediation of the feeding preferences of scatter-hoarding rodents, are poorly understood. In this study, we created a series of artificial 'seeds' that only differed in tannin concentration and the type of tannin, and placed them in a pine forest in the Shangri-La Alpine Botanical Garden, Yunnan Province of China. Two rodent species ( Apodemus latronum and A. chevrieri) showed significant preferences for 'seeds' with different tannin concentrations. A significantly higher proportion of seeds with low tannin concentration were consumed in situ compared with seeds with a higher tannin concentration. Meanwhile, the tannin concentration was significantly positively correlated with the proportion of seeds cached. The different types of tannin (hydrolysable tannin vs condensed tannin) did not differ significantly in their effect on the proportion of seeds eaten in situ vs seeds cached. Tannin concentrations had no significant effect on the distance that cached seeds were carried, which suggests that rodents may respond to different seed traits in deciding whether or not to cache seeds and how far they will transport seeds.

Wang, Bo; Chen, Jin

2008-11-01

267

WWWWWetland Seed Banks:etland Seed Banks:etland Seed Banks:etland Seed Banks:etland Seed Banks: Research in Natural and Created WResearch in Natural and Created WResearch in Natural and Created WResearch in Natural and Created WResearch in Natural and Cre  

E-print Network

1 WWWWWetland Seed Banks:etland Seed Banks:etland Seed Banks:etland Seed Banks:etland Seed Banks). One of the most important structural compo- nents of the wetland ecosystem­ the seed bank influence recruitment of naturally colonizing vegetation from the seed bank (Reinhartz and Warne 1993

268

Effects of seed origin and irrigation on survival and growth of transplanted shrubs  

SciTech Connect

Revegetation is difficult in the Mojave Desert due to limited, erratic precipitation and extreme temperatures. Establishing plant cover by transplanting native shrubs is known to be a promising technique, but many questions still remain regarding its use on a large operational scale. A study was initiated on the US Department of Energy Nevada Test Site (NTS) to determine the effects of seed origin and irrigation on survival and growth of transplanted shrubs. Plants of three species (Larrea tridentata, Ambrosia dumosa, and Atriplex canescens) were grown in a greenhouse and hardened outdoors. Plants of all three species were produced from two seed sources: (1) seed collected from the NTS (Mojave Desert), and (2) commercially available seed collected from outside the NTS. One-year-old containerized plants (180 of each species) were transplanted to a site on the NTS and irrigated with two liters of water at one of the following frequencies: (1) at time of planting only, (2) at time of planting and monthly during the first growing season, and (3) at time of planting and twice monthly during the first growing season. After 16 months, survival of all species was generally greater than 80% and was unaffected by irrigation treatments. Survival of fourwing saltbush was significantly greater from local versus non-local seed. Survival of bursage and creosotebush was generally unaffected by seed origin. Shrub volumes regardless of species or seed origin increased during the first growing season, and then decreased during the second growing season. Shrub volumes for fourwing saltbush were significantly greater for shrubs from local versus non-local seed.

Winkel, V.K.

1995-10-01

269

Modification of Seed Germination Performance through Cold Plasma Chemistry Technology  

Microsoft Academic Search

growth regulators to seeds (Silcock and Smith, 1982; Taylor and Harman, 1990; Zarnstorff et al., 1994). One This study was conducted to determine if an alternate seed treat- such treatment is seed coating, the direct application of ment approach based on plasma chemistry would offer a more viable material to a seed surface. Seeds can be treated by alternative over

John C. Volin; Ferencz S. Denes; Raymond A. Young; Scott M. T. Park

2000-01-01

270

Seed fall and field germination of needlerush, Juncus effusus L  

Microsoft Academic Search

Juncus effusus seed fall during one growing season was determined by use of seed traps in a freshwater emergent wetland. These observations provided in situ seed fall estimates of ?4.0 million seeds per square m within the growing season, only 5% of which germinated during the 3-month field study, presumably because of unfavorable environmental conditions. Estimated biomass of seeds collected

Gary N. Ervin; Robert G. Wetzel

2001-01-01

271

Rationale for Seeding Grass on the Stanislaus Complex Burnt1  

E-print Network

Rationale for Seeding Grass on the Stanislaus Complex Burnt1 Earl C. Ruby2 Abstract: An emergency seeding grass as an emergency watershed treatment. The evaluation used site specific data to determine where to seed or not seed grass, and concluded that seeding grass on the flood source areas could

Standiford, Richard B.

272

Inheritance of seed colour in turnip rape ( Brassica campestris L.)  

Microsoft Academic Search

The inheritance of seed colour was investigated in the progenies of crosses between seven yellow seeded forms and a brown seeded one of turnip rape (Brassica campestris L.). Seed colour differences were found to be determined in each case by one or two genes with epistatic effect. Moreover, independent inheritance of hilum colour was observed. Seed colour was predominantly but

A. Schwetka

1982-01-01

273

Transgenic soybean seeds rebalance protein composition to maintain protein content  

Technology Transfer Automated Retrieval System (TEKTRAN)

The ontogeny of both seed structure and of seed storage substances results from a determinant genetic program that produces a population of nearly identical seeds. The seed’s developmental program to accumulate storage substances can be modified by nutrient availability and environmental conditions ...

274

Applicator Training Manual for: Seed Treatment Pest Control.  

ERIC Educational Resources Information Center

This manual gives general information on seed treatment and type of seeds which can be treated. Also discussed are the problems and pests commonly associated with seed diseases and the fungicides and insecticides used for seed treatment. Information is also given on seed treatment equipment such as dust treaters, slurry treaters, and direct…

TeKrony, Dennis M.

275

Genetic analysis of seed coat development in Arabidopsis  

E-print Network

and germination. Seed coats In the angiosperms, fertilization results in the formation of the seed from the ovule and the external environment during embryogenesis, dormancy and germination. Differentiation of the seed coat from, improve dormancy and germination, and enhance seed dispersal. In addition, the seed coat cells of some

Haughn, George

276

Tansley review Seed dormancy and the control of germination  

E-print Network

Tansley review Seed dormancy and the control of germination William E. Finch-Savage1 and Gerhard This section on applied aspects of the control of seed germination by dormancy is an additional part the seed at the molecular level? 5. Applied aspects of the control of germination by seed dormancy Seeds

Leubner, Gerhard

277

HORTSCIENCE 42(6):14361439. 2007. Primed Lettuce Seeds Exhibit  

E-print Network

. Lactuca sativa, seed priming, aging, viability equation, germination Abstract. The Ellis-Roberts seed contents. Seed priming, which can break dormancy and accelerate germination, can also reduce seed storage., 2002). Primed tomato seeds exhibited delayed germination and a lower mean ger

Bradford, Kent

278

Seed dynamics during forest succession in Costa Rica  

Microsoft Academic Search

Soil seed banks and current seed inputs each play a role in tropical succession. We compared the abundance and floristic composition of seeds from these two sources at a Costa Rican site by germinating seeds from the soil, measuring seed inputs for 3 yr, and monitoring the earliest colonists in a forest clearing.

K. R. Young; J. J. Ewel; B. J. Brown

1987-01-01

279

Biophysical Approaches to Measure and Predict Seed Longevity  

Technology Transfer Automated Retrieval System (TEKTRAN)

Reliable predictions of seed longevity would allow seed companies and seed bank managers to economize on processing, handling and monitoring of stored seeds and select lots that require regeneration or immediate sale. Seed longevity is difficult to predict because early symptoms of deterioration ar...

280

Dissolution and Resolidification of ... Seed during Top Seeded Melt Texturing of ...  

E-print Network

INTRODUCTION Top-seeded melt growth [1]-[2] has been widely used to prepare well-oriented large single-domained YBa 2 Cu 3 O 7-y (Y123) crystal [1]-[10]. SmBa 2 Cu 3 O 7-y (Sm123), NdBa 2 Cu 3 O 7y (Nd123) single crystals, or their 211 excessive forms whose melting points are higher than that of a Y123 phase, are generally used as seed materials to provide the artificial growth site. The seed crystals are, in general, placed on the top of the samples, and then the seeded samples are meltprocessed at temperatures below the melting points of the seed crystals. Under conditions of restricted nucleation, Y123 crystal grows at the seed with the same orientation as that of the seed. In principle, the seed materials should not melt during the processing, because maximum processing temperature is lower than their melting points. But th

Young A. Jee; Gye-won Hong; Chan-joong Kim

281

Effects of elevated CO2 and temperature on seed quality.  

PubMed

Successful crop production depends initially on the availability of high-quality seed. By 2050 global climate change will have influenced crop yields, but will these changes affect seed quality? The present review examines the effects of elevated carbon dioxide (CO2) and temperature during seed production on three seed quality components: seed mass, germination and seed vigour. In response to elevated CO2, seed mass has been reported to both increase and decrease in C3 plants, but not change in C4 plants. Increases are greater in legumes than non-legumes, and there is considerable variation among species. Seed mass increases may result in a decrease of seed nitrogen (N) concentration in non-legumes. Increasing temperature may decrease seed mass because of an accelerated growth rate and reduced seed filling duration, but lower seed mass does not necessarily reduce seed germination or vigour. Like seed mass, reported seed germination responses to elevated CO2 have been variable. The reported changes in seed C/N ratio can decrease seed protein content which may eventually lead to reduced viability. Conversely, increased ethylene production may stimulate germination in some species. High-temperature stress before developing seeds reach physiological maturity (PM) can reduce germination by inhibiting the ability of the plant to supply the assimilates necessary to synthesize the storage compounds required for germination. Nothing is known concerning the effects of elevated CO2 on seed vigour. However, seed vigour can be reduced by high-temperature stress both before and after PM. High temperatures induce or increase the physiological deterioration of seeds. Limited evidence suggests that only short periods of high-temperature stress at critical seed development stages are required to reduce seed vigour, but further research is required. The predicted environmental changes will lead to losses of seed quality, particularly for seed vigour and possibly germination. The seed industry will need to consider management changes to minimize the risk of this occurring. PMID:23495259

Hampton, J G; Boelt, B; Rolston, M P; Chastain, T G

2013-04-01

282

Cotton Planting Seed and Related Fiber Qualities.  

E-print Network

must be sterilized at the gins. Experience has indicated that unless seed treated in this manner are cooled by spread- ing or turning soon after heating, the germination is impaired. The ginning season is short with con- siderable volume... concentrated in a 50 to 60-day period. Growers are under pressure to harvest the crop quickly and have little opportunity to pre- serve the germination potential of the seed. The oil mill price for seed is usually attractive. The growers, therefore, depend...

Paulson, W. E.; Ward, J. M.

1956-01-01

283

Chemical solution seed layer for rabits tapes  

SciTech Connect

A method for making a superconducting article includes the steps of providing a biaxially textured substrate. A seed layer is then deposited. The seed layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different rare earth or transition metal cations. A superconductor layer is grown epitaxially such that the superconductor layer is supported by the seed layer.

Goyal, Amit; Paranthaman, Mariappan; Wee, Sung-Hun

2014-06-10

284

Supercritical fluid extraction of vegetable oil seeds  

Microsoft Academic Search

The extraction of oil from canola seeds using supercritical carbon dioxide was investigated. The basic equations which govern\\u000a the oil extraction from a bed of seeds were derived from first principles. The equations can be solved by standard numerical\\u000a techniques using experimentally determined parameters for the concentration of oil in the solvent in equilibrium with seeds\\u000a having a known oil

N. R. Bulley; M. Fattori; A. Meisen; L. Moyls

1984-01-01

285

Detoxification of castor seed meal by interaction with sal seed meal  

Microsoft Academic Search

Castor (Ricinus communis) seed meal was detoxified by a novel method of wet mixing with sal (Shorea robusta) seed meal so that the toxic constituents of castor seed meal were neutralized by tannins, the toxicants present in the sal\\u000a seed meal. The resulting product was innocuous, as revealed in the feeding studies in rats. The nutritional benefit of the\\u000a treated

V. M. Gandhi; K. M. Cherian; M. J. Mulky

1994-01-01

286

The restoration of sedge meadows: seed viability, seed germination requirements, and seedling growth of Carex species  

Microsoft Academic Search

To better understand how to establishCarex species from seed in created and restored wetlands, a series of experimental studies was conducted onCarex seed and seedlings. These studies included (1) the effect of seed age (1 to 18 months after collection) on viability and\\u000a germination, (2) storage conditions (+4,-4 or +4\\/-4°C; wet or dry) on seed germination, (3) soil moisture on

Arnold G. van der Valk; Tony L. Bremholm; Elizabeth Gordon

1999-01-01

287

Determining ‘threshold’ levels for seed-borne virus infection in seed stocks  

Microsoft Academic Search

There have been many advances in testing procedures to detect seed-borne virus infection in seed samples. However, scant attention has been given to the implications of improved test results in terms of the economic losses resulting from sowing seed stocks with different amounts of infection. For agricultural and horticultural industries to use the results of tests on representative samples, defined

Roger A. C. Jones

2000-01-01

288

MOISTURE, SEED COAT CHARACTERISTICS, AND DISINFECTION OF ARTIFICIALLY INOCULATED ALFALFA SEEDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Vegetable sprouts can be a vehicle for food borne illness. The seeds used for sprouts are considered the probable source of the pathogen contamination. Since naturally contaminated seeds have a very low pathogen level, artificially inoculated seeds are used to test decontamination methods. There a...

289

Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: where do all the seeds go?  

USGS Publications Warehouse

Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert—sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application.

DeFalco, Lesley A.; Esque, Todd C.; Nicklas, Melissa B.; Kane, Jeffrey M.

2012-01-01

290

Breaking seed coat dormancy with physical and chemical methods in tamarind (Tamarindus indica L.) seeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tamarind (Tamarindus indica L.) is an important tree crop in Africa and Asia. It is primarily propagated by grafting, which involves the generation of rootstock material. Tamarind seeds have an impermeable seed coat and need scarification for improved germination. In this study, tamarind seeds colle...

291

Buried Seed Banks as Indicators of Seed Output along an Altitudinal Gradient.  

ERIC Educational Resources Information Center

Study of buried seed banks (viable seeds deposited in the soil near parent plants) provides a relatively easy way of determining cumulative effects on seed production and species' altitudinal limits. Sites, methods, validity, interpretation, problems of collection on a mountain, and germination techniques are discussed. (Author/DH)

Thompson, K.

1985-01-01

292

Two-phase seed dispersal: linking the effects of frugivorous birds and seed-caching rodents.  

PubMed

Frugivorous birds disperse the seeds of many fruit-bearing plants, but the fate of seeds after defecation or regurgitation is often unknown. Some rodents gather and scatter hoard seeds, and some of these may be overlooked, germinate, and establish plants. We show that these two disparate modes of seed dispersal are linked in some plants. Rodents removed large (>25 mg) seeds from simulated bird feces (pseudofeces) at rates of 8-50%/day and scatter hoarded them in soil. Ants (Formica sibylla) also harvested some seeds and carried them to their nests. Rodents carried seeds 2.5+/-3.2 m to cache sites (maximum 12 m) and buried seeds at 8+/-7 mm depth. Enclosure studies suggest that yellow pine chipmunks (Tamias amoenus) and deer mice (Peromyscus maniculatus) made the caches. In spring, some seeds germinated from rodent caches and established seedlings, but no seedlings established directly from pseudofeces. This form of two-phase seed dispersal is important because each phase offers different benefits to plants. Frugivory by birds permits relatively long-range dispersal and potential colonization of new sites, whereas rodent caching moves seeds from exposed, low-quality sites (bird feces on the ground surface) to a soil environment that may help maintain seed viability and promote successful seedling establishment. PMID:15959820

Vander Wall, Stephen B; Kuhn, Kellie M; Gworek, Jennifer R

2005-09-01

293

UBC Social Ecological Economic Development Studies (SEEDS) Student Report SEEDS Gear Dryer  

E-print Network

UBC Social Ecological Economic Development Studies (SEEDS) Student Report SEEDS Gear Dryer Steven of a project/report". #12;i SEEDS Gear Dryer MECH 457 April 11th, 2011 Steven Baird Mike Dickson Jonathan Lau.........................................................................................................................B-1 Project Title: TREK Gear Dryer

294

Glyphosate and boron application effects on seed composition and seed boron in glyphosate-resistant soybean  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soybean seed is a major source of protein and oil in the world. Seed quality is determined by the content of protein and oil. Soybean seed contains five major fatty acids, saturated fatty acids (stearic and palmitic), and unsaturated fatty acids (oleic, linoleic, and linolenic). Both linoleic and li...

295

Converting Frequency Responses to Daily Frequency  

Cancer.gov

Frequency information on the DSQ in NHANES 2009-2010 was collected using a rate and time unit (e.g., 3 times per week). A different response format consisting of a set number of frequency categories is used in the self-administered paper questionnaire (link to questionnaire) ,. In both cases, the frequency responses are converted to a common unit of time, i.e. times per day.

296

The seeded growth of graphene  

NASA Astrophysics Data System (ADS)

In this paper, we demonstrate the seeded growth of graphene under a plasma chemical vapor deposition condition. First, we fabricate graphene nanopowders (~5 nm) by ball-milling commercial multi-wall carbon nanotubes. The graphene nanoparticles were subsequently subject to a direct current plasma generated in a 100 Torr 10%CH4 - 90%H2 gas mixture. The plasma growth enlarged, over one hour, the nuclei to graphene sheets larger than one hundred nm2 in area. Characterization by electron and X-ray diffraction, high-resolution transmission electron microscopy images provide evidence for the presence of monolayer graphene sheets.

Lee, Jae-Kap; Lee, Sohyung; Kim, Yong-Il; Kim, Jin-Gyu; Min, Bong-Ki; Lee, Kyung-Il; Park, Yeseul; John, Phillip

2014-07-01

297

The seeded growth of graphene  

PubMed Central

In this paper, we demonstrate the seeded growth of graphene under a plasma chemical vapor deposition condition. First, we fabricate graphene nanopowders (~5?nm) by ball-milling commercial multi-wall carbon nanotubes. The graphene nanoparticles were subsequently subject to a direct current plasma generated in a 100?Torr 10%CH4 - 90%H2 gas mixture. The plasma growth enlarged, over one hour, the nuclei to graphene sheets larger than one hundred nm2 in area. Characterization by electron and X-ray diffraction, high-resolution transmission electron microscopy images provide evidence for the presence of monolayer graphene sheets. PMID:25022816

Lee, Jae-Kap; Lee, Sohyung; Kim, Yong-Il; Kim, Jin-Gyu; Min, Bong-Ki; Lee, Kyung-Il; Park, Yeseul; John, Phillip

2014-01-01

298

ENHANCING SEED AVAILABILITY FOR THE HARD CLAM (Mercenaria mercenaria)  

E-print Network

ENHANCING SEED AVAILABILITY FOR THE HARD CLAM (Mercenaria mercenaria) Leslie N. Sturmer Charles M Oceanographic Institution. #12;Enhancing Seed Availability For the Hard Clam (Mercenaria mercenaria) Aquaculture................................................................................................ 1 Clam Seed Availability

Florida, University of

299

7 CFR 201.57a - Dormant seeds.  

Code of Federal Regulations, 2013 CFR

...AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration of the...germinate when provided the specified germination conditions for the kind of seed in question. (a) Viability...

2013-01-01

300

7 CFR 201.57a - Dormant seeds.  

Code of Federal Regulations, 2011 CFR

...AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration of the...germinate when provided the specified germination conditions for the kind of seed in question. (a) Viability...

2011-01-01

301

7 CFR 201.57a - Dormant seeds.  

Code of Federal Regulations, 2012 CFR

...AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration of the...germinate when provided the specified germination conditions for the kind of seed in question. (a) Viability...

2012-01-01

302

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2013 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2013-01-01

303

7 CFR 201.57a - Dormant seeds.  

Code of Federal Regulations, 2014 CFR

...AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration of the...germinate when provided the specified germination conditions for the kind of seed in question. (a) Viability...

2014-01-01

304

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2012 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2012-01-01

305

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2011 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2011-01-01

306

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2014 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2014-01-01

307

7 CFR 945.7 - Certified seed potatoes.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Certified seed potatoes. 945.7 Section 945.7 Agriculture...DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN CERTAIN DESIGNATED COUNTIES...Definitions § 945.7 Certified seed potatoes. Certified seed potatoes means...

2010-01-01

308

Seed Anatomy and Water Uptake in Relation to Seed Dormancy in Opuntia tomentosa (Cactaceae, Opuntioideae)  

PubMed Central

Background and Aims There is considerable confusion in the literature concerning impermeability of seeds with ‘hard’ seed coats, because the ability to take up (imbibe) water has not been tested in most of them. Seeds of Opuntia tomentosa were reported recently to have a water-impermeable seed coat sensu lato (i.e. physical dormancy), in combination with physiological dormancy. However, physical dormancy is not known to occur in Cactaceae. Therefore, the aim of this study was to determine if seeds of O. tomentosa are water-permeable or water-impermeable, i.e. if they have physical dormancy. Methods The micromorphology of the seed coat and associated structures were characterized by SEM and light microscopy. Permeability of the seed-covering layers was assessed by an increase in mass of seeds on a wet substrate and by dye-tracking and uptake of tritiated water by intact versus scarified seeds. Key Results A germination valve and a water channel are formed in the hilum–micropyle region during dehydration and ageing in seeds of O. tomentosa. The funicular envelope undoubtedly plays a role in germination of Opuntia seeds via restriction of water uptake and mechanical resistance to expansion of the embryo. However, seeds do not exhibit any of three features characteristic of those with physical dormancy. Thus, they do not have a water-impermeable layer(s) of palisade cells (macrosclereids) or a water gap sensu stricto and they imbibe water without the seed coat being disrupted. Conclusions Although dormancy in seeds of this species can be broken by scarification, they have physiological dormancy only. Further, based on information in the literature, it is concluded that it is unlikely that any species of Opuntia has physical dormancy. This is the first integrative study of the anatomy, dynamics of water uptake and dormancy in seeds of Cactaceae subfamily Opuntioideae. PMID:17298989

Orozco-Segovia, A.; Márquez-Guzmán, J.; Sánchez-Coronado, M. E.; Gamboa de Buen, A.; Baskin, J. M.; Baskin, C. C.

2007-01-01

309

Allison R. Kermode (ed.), Seed Dormancy: Methods and Protocols, Methods in Molecular Biology, vol. 773, DOI 10.1007/978-1-61779-231-1_18, Springer Science+Business Media, LLC 2011  

E-print Network

, but are used with increasing frequency in plant physiology. We have shown that high-resolution 1 H In Vivo 1 H-NMR Microimaging During Seed Imbibition, Germination, and Early Growth Victor Terskikh of plant seeds as small as 1 mm or even smaller. This chapter covers the methods associated

Leubner, Gerhard

310

Allelopathy due to purine alkaloids in tea seeds during germination  

Microsoft Academic Search

Summary  During imbibition of whole tea seeds (6 days) two purine alkaloids, caffeine and theobromine, did not decrease in the seed\\u000a coats and there was no increase in the seeds. In parallel with and after the breaking of seed coats there was a gradual release\\u000a of caffeine from coats of germinating seeds. By contrast, when the seed was freed from the

T. Suzuki; G. R. Waller

1987-01-01

311

Development of single-frequency laser for direct-detection wind lidar  

NASA Astrophysics Data System (ADS)

Recent progress in the research of a diode pumped, single-frequency 355nm laser for direct-detection wind lidar is presented. An injection seeded Nd:YAG laser was designed and built. A 'delay-ramp-fire' technique is used to achieve single-longitudinal-mode and stable energy. In this technique, stable time relation between the resonance peak and the pump pulse is achieved by feedback controlling the delay time between the pump pulse and the ramp voltage. The resulting single frequency pulses are amplified and frequency tripled. This laser operates at 100Hz and provides 30mJ/pulse of single-frequency 355 nm output with M2 value of <1.5. The frequency stability of the injection seeded Nd:YAG laser was investigated. The piezo hysteresis is found to be the main reason to cause the frequency unstability. In an environment avoiding high frequency vibration the frequency stability is determined by the motion linearity and ramping speed of the piezo actuator. A modified approach is proposed to improve the frequency stability of an injection seeded laser.

Zhou, Jun; Zang, Huaguo; Yu, Ting; Liu, Jiqiao; Chen, Weibiao

2007-09-01

312

Thermoperiodism in Cocklebur Seed Germination  

PubMed Central

Germination potential in nondormant, upper cocklebur (Xanthium pensylvanicum Wallr.) seeds, which were incapable of germinating under constant temperatures below 25 C in air, was increased by exposure to diurnally alternating temperatures. The cocklebur seeds failed to respond to the temperature fluctuations in the beginning of water imbibition, and their responsiveness appeared only after aerobic presoaking for a limited period or after anaerobic pretreatment for 1 to 3 days. Maximal germination was obtained after exposure to a thermoperiodic regime of 8 hours at 23 C and 16 hours at 8 C. A process occurring during the high temperature phase was aerobic and had to precede the inductive low temperature phase, its effect increasing with temperature. Critical minimum length of the inductive low temperature phase changed with the duration of a preceding anaerobiosis, for instance about 4 hours after 1 day anaerobiosis, but about 2 hours after 2 days. Percentage of subsequent germination was in proportion to the number of thermoperiodic cycles. A process of the inductive low temperature phase was not perturbed by inserting a brief higher temperature period into its phase; indeed, such insertion rather increased germination potential when performed in the earlier parts of the inductive low temperature phase. The effect of the low temperature survived for 13 to 17 hours during the higher temperature period. PMID:16660310

Esashi, Yohji; Tsukada, Yoshiya

1978-01-01

313

Protocol to Sterilize & Charcoal-Germinate Maize Seeds 1 PROTOCOL TO STERILIZE AND CHARCHOAL-GERMINATE MAIZE SEEDS  

E-print Network

Protocol to Sterilize & Charcoal-Germinate Maize Seeds 1 PROTOCOL TO STERILIZE AND CHARCHOAL-GERMINATE MAIZE SEEDS (Last revised August 2010) This protocol is used for germinating moldy seeds that would

Wurtele, Eve Syrkin

314

Seeded bermudagrass evaluations across the southeastern USA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seeded bermudagrasses are very popular with livestock producers because they are less expensive and easier to establish than vegetatively propagated bermudagrasses. Variety trials were planted in Texas, Mississippi, and Georgia in the spring of 2006 to compare seeded varieties and new breeding lines...

315

Grass Seed Structure and Seedling Emergence  

NSDL National Science Digital Library

This activity discusses both seed structure and seedling emergence in monocots. Through active learning elements, photos and text students will discover the basic anatomy of seeds and the function of each structure. The process of seedling emergence is presented in detail including the difference between emergence in cool-season and warm-season grasses.

316

Characterization of Milkweed (Asclepias spp.) Seed Proteins  

Technology Transfer Automated Retrieval System (TEKTRAN)

Milkweed (Asclepias spp.) is a crop grown mainly for the production of floss used as hypoallergenic fillers in comforters and pillows. The seeds end up as by-products. Milkweed seed contains 21% oil and 30% crude protein (dry basis). The oil is similar in quality to soybean oil, but there is no i...

317

Comparative seed morphology of Mexican Nymphaea species  

Microsoft Academic Search

Seed morphology was studied in 10 species belonging to three subgenera of Nymphaea occurring in Mexico: subgenus Brachyceras (N. ampla, N. elegans, N. gracilis, N. pulchella); subgenus Hydrocallis (N. amazonum, N. conardii, N. jamesoniana, N. novogranatensis); and subgenus Nymphaea (N. mexicana, N. odorata). Phenetic relationships of Mexican species of Nymphaea were studied by cluster analysis (UPGMA). Among subgenera, the seeds

Jaime Bonilla-Barbosa; Alejandro Novelo; Yolanda Hornelas Orozco; Judith Márquez-Guzmán

2000-01-01

318

Seed Development in Lesquerellar fendleri (L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The morphological, physiological and biochemical changes during seed development of Lesquerella fendleri was investigated from 7 days after pollination (DAP) to desiccation. The entire course of seed development lasted about 49 days and it can be divided to seven continuous stages (I to VII). During...

319

Fungal endophytes in green coffee seeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Green coffee seeds from Colombia, Guatemala, India, Kenya, Papua New Guinea, Puerto Rico, and Vietnam were sampled for the presence of fungal endophytes. Sections of surface sterilized seeds were plated on yeast malt agar, and fungal growth was isolated for subsequent DNA extraction and sequencing....

320

Digestibility of proteins in buckwheat seed  

Microsoft Academic Search

The digestibility of proteins in buckwheat seed was studied. There was a difference in susceptibility to proteolytic action between buckwheat proteins and some other proteins, with buckwheat proteins being less digestible by pepsin than hemoglobin and ovalbumin. Electrophoretic analysis indicated that the major component of the albumin in buckwheat seed was less susceptible to pepsin action . The relationship between

Kiyokazu Ikeda; Masayo Kishida

1993-01-01

321

Improving photoacoustic imaging contrast of brachytherapy seeds  

NASA Astrophysics Data System (ADS)

Prostate brachytherapy is a form of radiotherapy for treating prostate cancer where the radiation sources are seeds inserted into the prostate. Accurate localization of seeds during prostate brachytherapy is essential to the success of intraoperative treatment planning. The current standard modality used in intraoperative seeds localization is transrectal ultrasound. Transrectal ultrasound, however, suffers in image quality due to several factors such speckle, shadowing, and off-axis seed orientation. Photoacoustic imaging, based on the photoacoustic phenomenon, is an emerging imaging modality. The contrast generating mechanism in photoacoustic imaging is optical absorption that is fundamentally different from conventional B-mode ultrasound which depicts changes in acoustic impedance. A photoacoustic imaging system is developed using a commercial ultrasound system. To improve imaging contrast and depth penetration, absorption enhancing coating is applied to the seeds. In comparison to bare seeds, approximately 18.5 dB increase in signal-to-noise ratio as well as a doubling of imaging depth are achieved. Our results demonstrate that the coating of the seeds can further improve the discernibility of the seeds.

Pan, Leo; Baghani, Ali; Rohling, Robert; Abolmaesumi, Purang; Salcudean, Septimiu; Tang, Shuo

2013-03-01

322

Prostate brachytherapy seed segmentation using spoke transform  

NASA Astrophysics Data System (ADS)

Permanent implantation of radioactive seeds is a viable and effective therapeutic option widely used today for early stage prostate cancer. In order to perform intraoperative dosimetry the seed locations must be determined accurately with high efficiency. However, the task of seed segmentation is often hampered by the wide range of signal-to-noise ratios represented in the x-ray images due to highly non-uniform background. To circumvent the problem we have developed a new method, the spoke transform, to segment the seeds from the background. This method uses spoke-like rotating line segments within the two concentric windows. The mean intensity value of the pixels that fall on each rotated line segment best describing the intersection between the seed that we are trying to segment is chosen. The inner window gives an indication of the background level immediately surrounding the seeds. The outer window is an isolated region not being segmented and represents a non-seed area in need of enhancement and a detection decision. The advantages of the method are its ability (1) to work with spatially varying local backgrounds and (2) to segment the hidden seeds. Pd-103 and I-125 images demonstrate the effectiveness of the spoke transform.

Lam, Steve; Marks, Robert J., II; Cho, Paul S.

2001-07-01

323

The conservation physiology of seed dispersal  

PubMed Central

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

Ruxton, Graeme D.; Schaefer, H. Martin

2012-01-01

324

Software Tools for Weed Seed Germination Modeling  

Technology Transfer Automated Retrieval System (TEKTRAN)

The next generation of weed seed germination models will need to account for variable soil microclimate conditions. In order to predict this microclimate environment we have developed a suite of individual tools (models) that can be used in conjunction with the next generation of weed seed germinati...

325

DO MICROBES INFLUENCE SEED BANK DYNAMICS?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Reduction of seed bank persistence is an important goal for integrated weed management systems. Recent interest in more biological-based weed management strategies has led to closer examination of the role of soil microorganisms. Seeds of many annual weeds can persist in soils, indicating the pres...

326

Prickly lettuce control in alfalfa seed production.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds are particularly troublesome in alfalfa grown for seed due to the wider row spacing and the lack of multiple cuttings compared to alfalfa grown for hay. Prickly lettuce is often an escape weed in alfalfa seed production fields as it can germinate throughout the entire year and is naturally tol...

327

Seed Dispersal Velocity in Four Dwarfmistletoes  

Microsoft Academic Search

By means of a high-speed photographic technique, the initial velocities of seeds were studied as they were expelled from the fruits of four Colorado dwarfmistletoes: Arceuthobium douglasii, A. campylopodum f. cyanocarpum, A. vaginatum f. cryptopodum, and A. americanum. Velocities of the seeds of the latter two species averaged 2600 centimeters per second and were significantly greater than those of the

T. E. Hinds; F. G. Hawksworth

1965-01-01

328

Extractors with Weak Random Seeds Weizmann Institute  

E-print Network

to extract randomness from a weak random source. For every such extractor E, with seed of length d, weExtractors with Weak Random Seeds Ran Raz # Weizmann Institute ran.raz@weizmann.ac.il Abstract We show how to extract random bits from two or more independent weak random sources in cases where only

Raz, Ran

329

Seed predators exert selection on the subindividual variation of seed size.  

PubMed

Subindividual variation among repeated organs in plants constitutes an overlooked level of variation in phenotypic selection studies, despite being a major component of phenotypic variation. Animals that interact with plants could be selective agents on subindividual variation. This study examines selective pressures exerted during post-dispersal seed predation and germination on the subindividual variation of seed size in hawthorn (Crataegus monogyna). With a seed offering experiment and a germination test, we estimated phenotypic selection differentials for average and subindividual variation of seed size due to seed predation and germination. Seed size affects germination, growth rate and the probability of an individual seed of escaping predation. Longer seeds showed higher germination rates, but this did not result in significant selection on phenotypes of the maternal trees. On the other hand, seed predators avoided wider seeds, and by doing so exerted phenotypic selection on adult average and subindividual variation of seed size. The detected selection on subindividual variation suggests that the levels of phenotypic variation within individual plants may be, at least partly, the adaptive consequence of animal-mediated selection. PMID:24176051

Sobral, M; Guitián, J; Guitián, P; Larrinaga, A R

2014-07-01

330

Alterations in seed development gene expression affect size and oil content of Arabidopsis seeds.  

PubMed

Seed endosperm development in Arabidopsis (Arabidopsis thaliana) is under control of the polycomb group complex, which includes Fertilization Independent Endosperm (FIE). The polycomb group complex regulates downstream factors, e.g. Pheres1 (PHE1), by genomic imprinting. In heterozygous fie mutants, an endosperm develops in ovules carrying a maternal fie allele without fertilization, finally leading to abortion. Another endosperm development pathway depends on MINISEED3 (a WRKY10 transcription factor) and HAIKU2 (a leucine-rich repeat kinase). While the role of seed development genes in the embryo and endosperm establishment has been studied in detail, their impact on metabolism and oil accumulation remained unclear. Analysis of oil, protein, and sucrose accumulation in mutants and overexpression plants of the four seed development genes revealed that (1) seeds carrying a maternal fie allele accumulate low oil with an altered composition of triacylglycerol molecular species; (2) homozygous mutant seeds of phe1, mini3, and iku2, which are smaller, accumulate less oil and slightly less protein, and starch, which accumulates early during seed development, remains elevated in mutant seeds; (3) embryo-specific overexpression of FIE, PHE1, and MINI3 has no influence on seed size and weight, nor on oil, protein, or sucrose content; and (4) overexpression of IKU2 results in seeds with increased size and weight, and oil content of overexpressed IKU2 seeds is increased by 35%. Thus, IKU2 overexpression represents a novel strategy for the genetic manipulation of the oil content in seeds. PMID:24014578

Fatihi, Abdelhak; Zbierzak, Anna Maria; Dörmann, Peter

2013-10-01

331

Modeling and analysis of a density-dependent stochastic integral projection model for a disturbance specialist plant and its seed bank.  

PubMed

In many plant species dormant seeds can persist in the soil for one to several years. The formation of these seed banks is especially important for disturbance specialist plants, as seeds of these species germinate only in disturbed soil. Seed movement caused by disturbances affects the survival and germination probability of seeds in the seed bank, which subsequently affect population dynamics. In this paper, we develop a stochastic integral projection model for a general disturbance specialist plant-seed bank population that takes into account both the frequency and intensity of random disturbances, as well as vertical seed movement and density-dependent seedling establishment. We show that the probability measures associated with the plant-seed bank population converge weakly to a unique measure, independent of initial population. We also show that the population either persists with probability one or goes extinct with probability one, and provides a sharp criteria for this dichotomy. We apply our results to an example motivated by wild sunflower (Helianthus annuus) populations, and explore how the presence or absence of a "storage effect" impacts how a population responds to different disturbance scenarios. PMID:24916367

Eager, Eric Alan; Rebarber, Richard; Tenhumberg, Brigitte

2014-07-01

332

Breaking of seed dormancy by catalase inhibition.  

PubMed Central

Germination of some dormant seeds is promoted by solutions of thiourea, sodium nitrite, and hydroxylamine salts. The promotions are accompanied by irreversible inhibition of catalase (EC 1.11.1.6) in extracts from the seeds. The seeds are also promoted in germination by catechol and pyrogallol solutions. These effects are recorded for lettuce (Lactuca sativa L. cv. Grand Rapids) and pigweed (Amaranthus albus L.) seeds. The results indicae that metabolically derived hydrogen peroxide, spared from decomposition by catalase inhibition, oxidizes reduced NADPH required as the oxidant in the pentose pathway of glucose use. The metabolic system for such use of H2O2 involves the enzymes, peroxidase (EC 1.11.1.7) and pyridine nucleotide quinone oxidoreductase (EC 1.6.99.2), which are present in the dormant seed prior to imbibition of water. PMID:235126

Hendricks, S B; Taylorson, R B

1975-01-01

333

Comparison of germination and seed bank dynamics of dimorphic seeds of the cold desert halophyte Suaeda corniculata subsp. mongolica  

PubMed Central

Background and Aims Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but it is unknown how this difference contributes to maintenance and regeneration of populations. The primary aim of this study was to compare the seed bank dynamics, including dormancy cycling, of the two seed morphs (black and brown) of the cold desert halophyte Suaeda corniculata and, if differences were found, to determine their influence on regeneration of the species. Method Seeds of the two seed morphs were buried, exhumed and tested monthly for 24 months over a range of temperatures and salinities, and germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were also investigated for the two morphs. Key Results Black seeds had an annual dormancy/non-dormancy cycle, while brown seeds, which were non-dormant at maturity, remained non-dormant. Black seeds also exhibited an annual cycle in sensitivity of germination to salinity. Seedlings derived from black seeds emerged in July and August and those from brown seeds in May. Seedlings were recruited from 2·6 % of the black seeds and from 2·8 % of the brown seeds in the soil, and only 0·5 % and 0·4 % of the total number of black and brown seeds in the soil, respectively, gave rise to seedlings that survived to produce seeds. Salinity and water stress induced dormancy in black seeds and decreased viability of brown seeds. Brown seeds formed only a transient soil seed bank and black seeds a persistent seed bank. Conclusions The presence of a dormancy cycle in black but not in brown seeds of S. corniculata and differences in germination requirements of the two morphs cause them to differ in their germination dynamics. The study contributes to our limited knowledge of dormancy cycling and seed bank formation in species producing heteromorphic seeds. PMID:22975287

Cao, Dechang; Baskin, Carol C.; Baskin, Jerry M.; Yang, Fan; Huang, Zhenying

2012-01-01

334

Seed banks in a degraded desert shrubland: Influence of soil surface condition and harvester ant activity on seed abundance  

Microsoft Academic Search

We compared seed banks between two contrasting anthropogenic surface disturbances (compacted, trenched) and adjacent undisturbed controls to determine whether site condition influences viable seed densities of perennial and annual Mojave Desert species. Viable seeds of perennials were rare in undisturbed areas (3–4 seeds\\/m2) and declined to <1 seed\\/m2 within disturbed sites. Annual seed densities were an order of magnitude greater

L. A. DeFalco; T. C. Esque; J. M. Kane; M. B. Nicklas

2009-01-01

335

Weed seeds on clothing: a global review.  

PubMed

Weeds are a major threat to biodiversity including in areas of high conservation value. Unfortunately, people may be unintentionally introducing and dispersing weed seeds on their clothing when they visit these areas. To inform the management of these areas, we conducted a systematic quantitative literature review to determine the diversity and characteristics of species with seeds that can attach and be dispersed from clothing. Across 21 studies identified from systematic literature searches on this topic, seeds from 449 species have been recorded on clothing, more than double the diversity found in a previous review. Nearly all of them, 391 species, are listed weeds in one or more countries, with 58 classified as internationally-recognised environmental weeds. When our database was compared with weed lists from different countries and continents we found that clothing can carry the seeds of important regional weeds. A total of 287 of the species are listed as aliens in one or more countries in Europe, 156 are invasive species/noxious weeds in North America, 211 are naturalized alien plants in Australia, 97 are alien species in India, 33 are invasive species in China and 5 are declared weeds/invaders in South Africa. Seeds on the clothing of hikers can be carried to an average distance of 13 km, and where people travel in cars, trains, planes and boats, the seeds on their clothing can be carried much further. Factors that affect this type of seed dispersal include the type of clothing, the type of material the clothing is made from, the number and location of the seeds on plants, and seed traits such as adhesive and attachment structures. With increasing use of protected areas by tourists, including in remote regions, popular protected areas may be at great risk of biological invasions by weeds with seeds carried on clothing. PMID:24956465

Ansong, Michael; Pickering, Catherine

2014-11-01

336

Genotyping of Endosperms to Determine Seed Dormancy Genes Regulating Germination Through Embryonic, Endospermic, or Maternal Tissues in Rice  

PubMed Central

Seed dormancy is imposed by one or more of the embryo, endosperm, and maternal tissues that belong to two generations and represent two ploidy levels. Many quantitative trait loci (QTL) have been identified for seed dormancy as measured by gross effects on reduced germination rate or delayed germination in crop or model plants. This research developed an endosperm genotype?based genetic approach to determine specific tissues through which a mapped QTL regulates germination using rice as a model. This approach involves testing germination velocity for partially after-ripened seeds harvested from single plants heterozygous for a tested QTL and genotyping endosperms from individual germinated and nongerminated seeds with a codominant DNA marker located on the QTL peak region. Information collected about the QTL includes genotypic frequencies in germinated and/or nongerminated subpopulations; allelic frequency distributions during a germination period; endosperm or embryo genotypic differences in germination velocity; and genotypic frequencies for gametes involved in the double fertilization to form the sampled seeds. Using this approach, the seed dormancy loci SD12, SD1-2, and SD7-1 were determined to regulate germination through the embryo, endosperm, and maternal tissues, respectively; SD12 and SD1-2 acted additively on germination velocity in the offspring tissues; and SD12 also was associated with the preferential fertilization of male gametes in rice. This new genetic approach can be used to characterize mapped genes/QTL for tissue-specific functions in endospermic seeds and for marker-assisted selection of QTL alleles before or immediately after germination in crop breeding. PMID:25480961

Gu, Xing-You; Zhang, Jinfeng; Ye, Heng; Zhang, Lihua; Feng, Jiuhuan

2014-01-01

337

Genotyping of Endosperms To Determine Seed Dormancy Genes Regulating Germination Through Embryonic, Endospermic or Maternal Tissues in Rice.  

PubMed

Seed dormancy is imposed by one or more of the embryo, endosperm and maternal tissues that belong to two generations and represent two ploidy levels. Many quantitative trait loci (QTL) have been identified for seed dormancy as measured by gross effects on reduced germination rate or delayed germination in crop or model plants. This research developed an endosperm genotype-based genetic approach to determine specific tissues through which a mapped QTL regulates germination using rice as a model. This approach involves testing germination velocity for partially after-ripened seeds harvested from single plants heterozygous for a tested QTL and genotyping endosperms from individual germinated and non-germinated seeds with a co-dominant DNA marker located on the QTL peak region. Information collected about the QTL includes genotypic frequencies in germinated and/or non-germinated subpopulations; allelic frequency distributions during a germination period; endosperm or embryo genotypic differences in germination velocity; and genotypic frequencies for gametes involved in the double fertilization to form the sampled seeds. Using this approach, the seed dormancy loci SD12, SD1-2, and SD7-1 were determined to regulate germination through the embryo, endosperm and maternal tissues, respectively; SD12 and SD1-2 acted additively on germination velocity in the offspring tissues; and SD12 was also associated with the preferential fertilization of male gametes in rice. This new genetic approach can be used to characterize mapped genes/QTL for tissue-specific functions in endospermic seeds and for marker-assisted selection of QTL alleles before or immediately after germination in crop breeding. PMID:25480961

Gu, Xing-You; Zhang, Jinfeng; Ye, Heng; Zhang, Lihua; Feng, Jiuhuan

2014-12-01

338

Direct somatic embryogenesis and synthetic seed production from Paulownia elongata.  

PubMed

We have developed a reproducible system for efficient direct somatic embryogenesis from leaf and internodal explants of Paulownia elongata. The somatic embryos obtained were subsequently encapsulated as single embryos to produce synthetic seeds. Several plant growth regulators [6-benzylaminopurine, indole-3-acetic acid, alpha-naphthaleneacetic acid, kinetin and thidiazuron (TDZ)] alone or in combination were tested for their capacity to induce somatic embryogenesis. The highest induction frequencies of somatic embryos were obtained on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 0.6% Phytagel, 500 mg l(-1) casein hydrolysate and 10 mg l(-1) TDZ (medium MS10). Somatic embryos were induced from leaf (69.8%) and internode (58.5%) explants on MS10 medium after 7 days. Subsequent withdrawal of TDZ from the induction medium resulted in the maturation and growth of the embryos into plantlets on MS basal media. The maturation frequency of somatic embryos from leaf and internodal explants was 50.8% and 45.8%, respectively. Subculturing of mature embryos led to their germination on the same medium with a germination frequency of 50.1% and 29.8% from leaf and internode explants, respectively. Somatic embryos obtained directly on leaf explants were used for encapsulation in liquid MS medium containing different concentrations of sodium alginate with a 30-min exposure to 50 m M CaCl(2). A 3% sodium alginate concentration provided a uniform encapsulation of the embryos with survival and germination frequencies of 73.7% and 53.3%, respectively. Storage at 4 degrees C for 30 days or 60 days significantly reduced the survival and complete germination frequencies of both encapsulated and non-encapsulated embryos relative to those of non-stored somatic embryos. However, the survival and germination rates of encapsulated embryos increased following storage at 4 degrees C. After 30 days or 60 days of storage, the survival rates of encapsulated embryos were 67.8% and 53.5% and the germination frequencies were 43.2% and 32.4%, respectively. These systems could be useful for the rapid clonal propagation and dissemination of synthetic seed material of Paulownia elongata. PMID:12827435

Ipekci, Z; Gozukirmizi, N

2003-08-01

339

Competition between meiotic and apomictic pathways during ovule and seed development results in clonality.  

PubMed

Meiotic and apomictic reproductive pathways develop simultaneously in facultative aposporous species, and compete to form a seed as a final goal. This developmental competition was evaluated in tetraploid genotypes of Paspalum malacophyllum in order to understand the low level of sexuality in facultative apomictic populations. Cyto-embryology on ovules, flow cytometry on seeds and progeny tests by DNA fingerprinting were used to measure the relative incidence of each meiotic or apomictic pathway along four different stages of the plant's life cycle, namely the beginning and end of gametogenesis, seed formation and adult offspring. A high variation in the frequencies of sexual and apomictic pathways occurred at the first two stages. A trend of radical decline in realized sexuality was then observed. Sexual and apomictic seeds were produced, but the efficiency of the sexual pathway dropped drastically, and exclusively clonal offspring remained. Both reproductive pathways are unstable at the beginning of development, and only the apomictic one remains functional. Key factors reducing sexuality are the faster growth and parthenogenetic development in the aposporous pathway, and an (epi)genetically negative background related to the extensive gene de-regulation pattern responsible for apomixis. The effects of inbreeding depression during post-fertilization development may further decrease the frequency of effective sexuality. PMID:23127139

Hojsgaard, Diego H; Martínez, Eric J; Quarin, Camilo L

2013-01-01

340

Effects of prolonged exposure of lettuce seeds to HZE particles on orbital stations  

NASA Astrophysics Data System (ADS)

In a study of the biological effects of cosmic HZE particles, lettuce (Lactuca sativa) seeds were flown on the orbital stations Salyut 6 and 7 for varying periods of time (from 40 to 457 days). The dependence of the biological damage on flight duration, physical parameters and the fact of passage of an HZE particle through the seed was estimated using the criterion of the frequency of aberrant cells. The arrangement of the flight biological container Biobloc made it possible to trace the location of tracks of individual HZE particles with Z>=6 and LET 200 keV/um. In seeds hit by HZE particles, for all exposure times, a statistically significant much higher yield of aberrant cells and also of cells containing multiple chromosome aberrations was observed than in the control material. The frequency of aberrant cells is markedly higher (by a factor of 1,5) in seeds hit than in non-hit ones. The changes of the yield of aberrant cells as a function of the absorbed dose (3.2-63.4 mGy) and the fluence (4.8-44.2 particles/cm2) are linear for the exposure duration ranging from 40 to 457 days.

Nevzgodina, L. V.; Maksimova, E. N.; Kaminskaya, E. V.

341

Physical dormancy in seeds: a game of hide and seek?  

PubMed

Historically, 'physical dormancy', or 'hard seededness', where seeds are prevented from germinating by a water-impermeable seed coat, is viewed as a dormancy mechanism. However, upon water uptake, resumption of metabolism leads to the unavoidable release of volatile by-products, olfactory cues that are perceived by seed predators. Here, we examine the hypothesis that hard seeds are an anti-predator trait that evolved in response to powerful selection by small mammal seed predators. Seeds of two legume species with dimorphic seeds ('hard' and 'soft'), Robinia pseudoacacia and Vicia sativa, were offered to desert hamsters (Phodopus roborovskii) in a series of seed removal studies examining the differences in seed harvest between hard and soft seeds. Volatile compounds emitted by dry and imbibed soft seeds were identified by headspace gas chromatography-mass spectrometry (GC-MS). Fourteen main volatile compounds were identified, and hamsters readily detected both buried imbibed seeds and an artificial 'volatile cocktail' that mimicked the scent of imbibed seeds, but could not detect buried hard or dry soft seeds. We argue that physical dormancy has evolved to hide seeds from mammalian predators. This hypothesis also helps to explain some otherwise puzzling features of hard seeds and has implications for seed dispersal. PMID:23421728

Paulsen, Torbjørn Rage; Colville, Louise; Kranner, Ilse; Daws, Matthew I; Högstedt, Göran; Vandvik, Vigdis; Thompson, Ken

2013-04-01

342

Transform-limited, achromatic injection-seeded terahertz-wave parametric generator  

NASA Astrophysics Data System (ADS)

A review to our effort on developing the transform-limited, frequency-agile terahertz-wave parametric generator (TPG) is presented. A frequency-agile THz-wave generation is realized by introducing the injection-seeding method and the optical design for the stationary dispersion-compensation The purity of the THz-wave frequency was dramatically improved to ?v/v<10-4. Simultaneously, the THz-wave output was several hundred times higher than that of a conventional TPG. In addition, a wide frequency tuning with fast tuning speed were realized. The THz-wave frequency can be set randomly or scanned continuously over a frequency range from 0.6 THz to 2.4 THz with narrow linewidth of sub 100 MHz. Furthermore, a tabletop, high-performance THz-wave gas spectrometer based on this achromatic injection-seeded TPG was developed. To demonstrate the potential of this system, we performed the measurement of the absorption line due to rotational transitions of the water molecules and determined their pressure-broadening coefficient.

Guo, R.; Minamide, H.; Ito, H.

2011-02-01

343

Timing of seed dispersal generates a bimodal seed bank depth distribution.  

PubMed

The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that develop deep soil cracks during the dry season, it is possible that some seeds fall down cracks and rapidly become deeply buried. We investigated this possibility for three dominant clonal perennials (Scirpus maritimus, S. litoralis, and Juncus subulatus) in the Doñana salt marsh, a nontidal marsh with a Mediterranean climate located in southwest Spain. Two species, which shed most of their seed during the dry season and have seeds with low buoyancy, had bimodal viable seed depth distributions, with peak densities at the surface and at 16-20 cm. A third species, which shed most seeds after soil cracks had closed and had seeds with high buoyancy, had viable seeds only in surface soil. Bimodal seed bank depth distributions may be relatively common in seasonally dry habitats with fine-textured soils, but their ecological significance has not been investigated. PMID:21646093

Espinar, José L; Thompson, Ken; García, Luis V

2005-10-01

344

A seed predator drives the evolution of a seed dispersal mutualism  

PubMed Central

Although antagonists are hypothesized to impede the evolution of mutualisms, they may simultaneously exert selection favouring the evolution of alternative mutualistic interactions. We found that increases in limber pine (Pinus flexilis) seed defences arising from selection exerted by a pre-dispersal seed predator (red squirrel Tamiasciurus hudsonicus) reduced the efficacy of limber pine's primary seed disperser (Clark's nutcracker Nucifraga columbiana) while enhancing seed dispersal by ground-foraging scatter-hoarding rodents (Peromyscus). Thus, there is a shift from relying on primary seed dispersal by birds in areas without red squirrels, to an increasing reliance on secondary seed dispersal by scatter-hoarding rodents in areas with red squirrels. Seed predators can therefore drive the evolution of seed defences, which in turn favour alternative seed dispersal mutualisms that lead to major changes in the mode of seed dispersal. Given that adaptive evolution in response to antagonists frequently impedes one kind of mutualistic interaction, the evolution of alternative mutualistic interactions may be a common by-product. PMID:18460433

Siepielski, Adam M; Benkman, Craig W

2008-01-01

345

Seed production temperature regulation of primary dormancy occurs through control of seed coat phenylpropanoid metabolism.  

PubMed

Environmental changes during seed production are important drivers of lot-to-lot variation in seed behaviour and enable wild species to time their life history with seasonal cues. Temperature during seed set is the dominant environmental signal determining the depth of primary dormancy, although the mechanisms though which temperature changes impart changes in dormancy state are still only partly understood. We used molecular, genetic and biochemical techniques to examine the mechanism through which temperature variation affects Arabidopsis thaliana seed dormancy. Here we show that, in Arabidopsis, low temperatures during seed maturation result in an increase in phenylpropanoid gene expression in seeds and that this correlates with higher concentrations of seed coat procyanidins. Lower maturation temperatures cause differences in coat permeability to tetrazolium, and mutants with increased seed coat permeability and/or low procyanidin concentrations are less able to enter strongly dormant states after exposure to low temperatures during seed maturation. Our data show that maternal temperature signalling regulates seed coat properties, and this is an important pathway through which the environmental signals control primary dormancy depth. PMID:25412428

MacGregor, Dana R; Kendall, Sarah L; Florance, Hannah; Fedi, Fabio; Moore, Karen; Paszkiewicz, Konrad; Smirnoff, Nicholas; Penfield, Steven

2015-01-01

346

A seed predator drives the evolution of a seed dispersal mutualism.  

PubMed

Although antagonists are hypothesized to impede the evolution of mutualisms, they may simultaneously exert selection favouring the evolution of alternative mutualistic interactions. We found that increases in limber pine (Pinus flexilis) seed defences arising from selection exerted by a pre-dispersal seed predator (red squirrel Tamiasciurus hudsonicus) reduced the efficacy of limber pine's primary seed disperser (Clark's nutcracker Nucifraga columbiana) while enhancing seed dispersal by ground-foraging scatter-hoarding rodents (Peromyscus). Thus, there is a shift from relying on primary seed dispersal by birds in areas without red squirrels, to an increasing reliance on secondary seed dispersal by scatter-hoarding rodents in areas with red squirrels. Seed predators can therefore drive the evolution of seed defences, which in turn favour alternative seed dispersal mutualisms that lead to major changes in the mode of seed dispersal. Given that adaptive evolution in response to antagonists frequently impedes one kind of mutualistic interaction, the evolution of alternative mutualistic interactions may be a common by-product. PMID:18460433

Siepielski, Adam M; Benkman, Craig W

2008-08-22

347

Physical Activity Frequency & Health  

MedlinePLUS Videos and Cool Tools

... hand corner of the player. Physical Activity Frequency & Health HealthDay February 20, 2015 Related MedlinePlus Pages Exercise ... in a study on physical activity frequency and health. They reported their level of activity at the ...

348

Radio frequency pressure transducer  

Microsoft Academic Search

A novel system is reported here for the pressure measurement at microwave and millimetre-wave frequencies. This method consists in using a radio frequency transducer based on RF resonator. Accurate determination of the pressure is expected.

M. M. Jatlaoui; P. Pons; H. Aubert

2007-01-01

349

Frequency comb swept lasers  

E-print Network

We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep ...

Tsai, Tsung-Han

350

Do seed mass and family affect germination and juvenile performance in Knautia arvensis? A study using failure-time methods  

NASA Astrophysics Data System (ADS)

Germination and seedling establishment are vulnerable stages in the plant life cycle. We investigated how seed mass and family (progeny origin) affect germination and juvenile performance in the grassland herb Knautia arvensis. Seeds were produced by cross-pollination by hand. The fate of 15 individually weighed seeds from each of 15 plants was followed during a 3-month growth chamber experiment. Progeny origin affected germination, both through seed mass and as an independent factor. Two groups of progenies could be distinguished by having rapid or delayed germination. The two groups had similar mean seed masses, but a positive relationship between seed mass and germination rate could be established only among the rapidly germinating progenies. These biologically relevant patterns were revealed because timing of germination was taken into account in the analyses, not only frequencies. Time-to-event data were analysed with failure-time methods, which gave more stable estimates for the relation between germination and seed mass than the commonly applied logistic regression. Progeny origin and seed mass exerted less impact on later characters like juvenile survival, juvenile biomass, and rosette number. These characters were not affected by the timing of germination under the competition-free study conditions. The decrease in the effect of progeny origin from the seed and germination to the juvenile stages suggests that parental effects other than those contributing to the offspring genotype strongly influenced the offspring phenotype at the earliest life stages. Further, the division of progeny germination patterns into two fairly distinct groups indicates that there was a genetic basis for the variation in stratification requirements among parental plants. Field studies are needed to elucidate effects of different timing of germination in the seasonal grasslands that K. arvensis inhabits.

Vange, Vibekke; Heuch, Ivar; Vandvik, Vigdis

2004-05-01

351

Frequency reference in VSAT  

NASA Astrophysics Data System (ADS)

A low cost technique of frequency reference distribution within a VSAT network is discussed. This technique allows the use of a modestly frequency stable oscillator as the master frequency reference in the hub of a star-connected VSAT network. The need for extremely frequency stable OCXOs in VSATs is completely avoided. This technique was successfully incorporated in the early commercial VSAT networks. It contributes partially to the low cost nature of some of the VSAT networks available today.

Cheah, Jonathon Y. C.

1994-02-01

352

Sucrose metabolism in lima bean seeds  

SciTech Connect

Developing and germinating lima bean (Phaseolus lunatus var Cangreen) seeds were used for testing the sucrose synthase pathway, to examine the competition for uridine diphosphate (UDP) and pyrophosphate (PPi), and to identify adaptive and maintenance-type enzymes in glycolysis and gluconeogenesis. In developing seeds, sucrose breakdown was dominated by the sucrose synthase pathway; but in the seedling embryos, both the sucrose synthase pathway and acid invertase were active. UDPase activity was low and seemingly insufficient to compete for UDP during sucrose metabolism in seed development or germination. In contrast, both an acid and alkaline pyrophosphatase were active in seed development and germination. The set of adaptive enzymes identified in developing seeds were sucrose synthase, PPi-dependent phosphofructokinase, plus acid and alkaline pyrophosphatase; and, the adaptive enzymes identified in germinating seeds included the same set of enzymes plus acid invertase. The set of maintenance enzymes identified during development, in the dry seed, and during germination were UDP-glucopyrophosphorylase, neutral invertase, ATP and UTP-dependent fructokinase, glucokinase, phosphoglucomutase, ATP and UTP-dependent phosphofructokinase and sucrose-P synthase.

Xu, Dianpeng; Sung, Shijean, S.; Black, C.C. (Univ. of Georgia, Athens (USA))

1989-04-01

353

Analyzing characteristics of hybrid rice seed  

NASA Astrophysics Data System (ADS)

Incompletely closed glumes, germ on panicle and disease are three characteristics of hybrid rice seed, which are actual reasons of poor seed quality. To find how many and which categories should be classified to meet the demand of produce actually, the effects of various degree of incompletely closed glumes, germ on panicle and disease on ratio of germination in changed storage periods were studied with standard germination rate test. An electronic scanning microscope was used for micro-observation and measurement. Then the possibility of automation inspection was tested with a machine vision system. The measures of increasing quality of hybrid rice seed were discussed in the paper at last. In the light of the periods of treatment and the classification of characteristics, difference steps should be taken. Before storage, Seeds with germ or severe disease should be rejected at first. Then seeds with incompletely closed glumes or spot disease might be stored separately for a shorter time in dried condition and treated with antisepsis before using for some special fields with lower quality demand. The seeds with fine fissure between glumes should be stored in a strictly controlled condition separately and inspected before use, just like other normal and healthy seeds.

Cheng, Fang; Ying, Yibin

2004-03-01

354

Studies in Wild Oat Seed Dormancy  

PubMed Central

Seed of Avena fatua were shown to exhibit a characteristic loss of dormancy during dry storage at 25 C, whereas similar seed stored at 5 C maintained dormancy. 2-Chloroethylphosphonic acid was shown to increase germination of partly dormant seed imbibed under certain temperature regimes; a similar effect could not be established for fully dormant or fully nondormant seed. Using gas-liquid chromatography, natural ethylene levels were followed during imbibition of fully dormant and nondormant seed. A large peak in production was observed in the period prior to radicle emergence in the case of the nondormant seed. Measurements of ethylene production taken at 15 C, following periods of after-ripening in moist soil at either 5 or 25 C, indicated that endogenous production was unlikely to be a main cause of dormancy breakage in this species. The possibility that endogenous ethylene could play a role in natural dormancy breakage in aged seeds is discussed. The practical possibilities of 2-chloroethylphosphonic acid as a dormancy breaking agent in a field situation are outlined. PMID:16661675

Adkins, Stephen W.; Ross, James D.

1981-01-01

355

Effects of density and floral morph on pollen flow and seed reproduction of an endangered heterostylous herb, Primula sieboldii  

Microsoft Academic Search

Summary 1 We assessed the effects of population density and the spatial arrangement of genetically compatible mates on the seed set and pollen flow of a heterostylous, bumblebee-pollinated perennial, Primula sieboldii E. Morren (Primulaceae), by using an experimental popu- lation under natural pollination conditions. 2 We also examined the intermorph differences in the pollen dispersal distance and the frequency of

F. ISHIHAMA; S. UENO; Y. TSUMURA; I. WASHITANI

2006-01-01

356

Frequency diverse array radars  

Microsoft Academic Search

This paper presents a generalized structure for a frequency diverse array radar. In its simplest form, the frequency diverse array applies a linear phase progression across the aperture. This linear phase progression induces an electronic beam scan, as in a conventional phased array. When an additional linear frequency shift is applied across the elements, a new term is generated which

Paul Antonik; Michael C. Wicks; Hugh D. Griffiths; Christopher J. Baker

2006-01-01

357

SUPERMASSIVE SEEDS FOR SUPERMASSIVE BLACK HOLES  

SciTech Connect

Recent observations of quasars powered by supermassive black holes (SMBHs) out to z {approx}> 7 constrain both the initial seed masses and the growth of the most massive black holes (BHs) in the early universe. Here we elucidate the implications of the radiative feedback from early generations of stars and from BH accretion for popular models for the formation and growth of seed BHs. We show that by properly accounting for (1) the limited role of mergers in growing seed BHs as inferred from cosmological simulations of early star formation and radiative feedback, (2) the sub-Eddington accretion rates of BHs expected at the earliest times, and (3) the large radiative efficiencies {epsilon} of the most massive BHs inferred from observations of active galactic nuclei at high redshift ({epsilon} {approx}> 0.1), we are led to the conclusion that the initial BH seeds may have been as massive as {approx}> 10{sup 5} M{sub Sun }. This presents a strong challenge to the Population III seed model, which calls for seed masses of {approx}100 M{sub Sun} and, even with constant Eddington-limited accretion, requires {epsilon} {approx}< 0.09 to explain the highest-z SMBHs in today's standard {Lambda}CDM cosmological model. It is, however, consistent with the prediction of the direct collapse scenario of SMBH seed formation, in which a supermassive primordial star forms in a region of the universe with a high molecule-dissociating background radiation field, and collapses directly into a 10{sup 4}-10{sup 6} M{sub Sun} seed BH. These results corroborate recent cosmological simulations and observational campaigns which suggest that these massive BHs were the seeds of a large fraction of the SMBHs residing in the centers of galaxies today.

Johnson, Jarrett L.; Whalen, Daniel J.; Li Hui [Nuclear and Particle Physics, Astrophysics and Cosmology Group (T-2), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Holz, Daniel E., E-mail: jlj@lanl.gov [Enrico Fermi Institute, Department of Physics, and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States)

2013-07-10

358

The oxygen requirement of germinating flax seeds  

NASA Astrophysics Data System (ADS)

Experiments for earth orbit are typically prepared on the ground and often germinated in orbit in order to study gravity effects on developing seedlings. Germination requires the breakdown of storage compounds and respiration. In orbit the formation of a water layer around the seed may further limit oxygen availability. Therefore, the oxygen content of the available gas volume is one of the limiting factors for seed germination. In preparation for an upcoming shuttle experiment (MICRO on STS-107) we studied germination and growth of flax (Linum usitatissimum L.) seedlings in the developed hardware. We tested per seed chamber (gas volume = 14 mL, O2 = 2.9 mL) between 4 to 32 seeds glued to germination paper by 1% (w/v) gum guar. A lexan cover and a gasket hermetically sealed each of the eight chambers. For imbibition of the seeds a previously optimized amount of distilled water was dispensed through sealed inlets. The seedlings were allowed to grow for either 32 to 48 h on a clinostat or without microgravity simulation. Then their root length was measured. With 32 seeds per chamber, four times the intended number of seeds for the flight, the germination rate decreased from 94 to 69%, and the root length was reduced by 20%. Experiments on the germination and root length in controlled atmospheres (5, 10, 15 and 21% O2 ) suggest that germination and growth for two days requires about 200 :l of O (1 mL air) per seed. Our2 experiments correlate oxygen dependency from seed mass and germination temperature, and analyze accumulation of gaseous metabolites (supported by NASA grant NAG10-0190).

Kuznetsov, O.; Hasenstein, K.

359

Cosmological matter perturbations with causal seeds  

E-print Network

We investigate linear matter density perturbations in models of structure formation with causal seeds. Under the fluid approximation, we obtain the analytic solutions using Green-function technique. Some incorrect solutions in the literature are corrected here. Based on this, we analytically prove that the matter density perturbations today are independent of the way the causal seeds were compensated into the background contents of the universe when they were first formed. We also find that the compensation scale depends not only on the dynamics of the universe, but also on the properties of the seeds near the horizon scale. It can be accurately located by employing our Green-function solutions.

Jiun-Huei Proty Wu

2001-04-15

360

Genomic Data and Annotation from the SEED  

DOE Data Explorer

The SEED Project has been extended to support metagenomic samples and concomitant analytical tools. Moreover, the number of genomes being introduced into SEED is growing very rapidly. Building a framework to support this growth while providing highly accurate annotations is centrally important to SEED. The project’s subsystem-based annotation strategy has become the technological foundation for addressing these challenges.(copied from Appendix 7 of Systems Biology Knowledgebase for a New Era in Biology, A Genomics:GTL Report from the May 2008 Workshop, DOE/SC-0113, Grequrick, S; Fredrickson, J.K.; Stevens, R., Pub March 1, 2009.)

Fonstein, Michael; Kogan, Yakov; Osterman, Andrei; Overbeek, Ross; Vonstein, Veronika The Fellowship for Interpretation of Genomes (FIG)

361

Freezing tolerance of conifer seeds and germinants.  

PubMed

Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation between seedlot hardiness and rate of germination. Germination rate and freezing tolerance of Douglas-fir and western red cedar seedlots was negatively correlated. There was a significant correlation between LT50 after 10 days in the growth chamber and minimum spring temperature at the location of seedlot origin for interior spruce and three seedlots of western red cedar, but no relationship was apparent for lodgepole pine and Douglas-fir. PMID:14652223

Hawkins, B J; Guest, H J; Kolotelo, D

2003-12-01

362

Seed gum of Stryphnodendron barbatiman (Barbatimao)  

SciTech Connect

Stryphnodendron barbatiman (barbatimao) is a native tree that is found throughout the {open_quotes}Cerrados,{close_quotes} a region of Central Brazil. Plant seeds, on water extraction, furnished 28 g% galactomannan (dry-weight basis), the monosaccharide composition of which (galactose to mannose ratio, 1.0:1.5) fits in the legume heteromannan group. This seed gum, after Sevag deproteinization, still retained 6 g% of associated protein and had a molecular weight of about 1.8 MD on gel filtration. A high intrinsic viscosity (1300 cP) was observed for the polysaccharide sample obtained after reflux of the crushed seeds in 80% aqueous methanol.

Reicher, F.; Leitner, S.C.S.; Fontana, J.D.; Correa, J.B.C.; Sierakowski, M.R. [UFPR, Curitiba (Brazil)

1991-12-31

363

Seed Dispersal Velocity in Four Dwarfmistletoes.  

PubMed

By means of a high-speed photographic technique, the initial velocities of seeds were studied as they were expelled from the fruits of four Colorado dwarfmistletoes: Arceuthobium douglasii, A. campylopodum f. cyanocarpum, A. vaginatum f. cryptopodum, and A. americanum. Velocities of the seeds of the latter two species averaged 2600 centimeters per second and were significantly greater than those of the first two, which averaged 2200 centimeters per second. The initial velocity of 526 seeds of the four dwarfmistletoes averaged 2400 centimeters per second. PMID:17842843

Hinds, T E; Hawksworth, F G

1965-04-23

364

The influence of urban land use on seed dispersal and wetland invasibility  

Microsoft Academic Search

Urban habitats are generally considered highly invaded by exotic species due to the frequency and extent of disturbance caused\\u000a by human activities and development. Our previous study had demonstrated that forested wetlands within residential areas are\\u000a more extensively invaded than wetlands within industrial–commercial areas. In this study, we investigate whether the structure\\u000a of the forest edge and seed dispersal can

Heather Bowman Cutway; Joan G. Ehrenfeld

2010-01-01

365

ALTERNATING MAGNETIC FIELD IRRADIATION EFFECTS ON THREE GENOTYPE MAIZE SEED FIELD PERFORMANCE  

Microsoft Academic Search

A b s t r a c t . In this study alternating magnetic field treatments at low frequency (60 Hz) with combinations of three magnetic flux densities (20, 60 and 100 mT) and three exposure times (7.5, 15 and 30 minutes) were used as pre-sowing seed treatments in three maize ( Zea mays L.) genotypes (CL-12 X CL-11, CL-4

Claudia Hernandez; Arturo Dominguez-Pacheco?; Aquiles Carballo Carballo; Alfredo Cruz-Orea; Rumen Ivanov

2009-01-01

366

Artificial Ripening of Sugar Pine Seeds Stanley L. Krugman  

E-print Network

Artificial Ripening of Sugar Pine Seeds Stanley L. Krugman U. S. FOREST SERVICE RESEARCH PAPER PSW --------------------------------------------------------------------------------------- 7 #12;Krugman, Stanley L. 1966. Artificial ripening of sugar pine seeds. Berkeley, Calif., Pacific seeds were collected and ripened either in the cone or in moist vermiculate. Seeds collected before

Standiford, Richard B.

367

Weed seed predation in organic and conventional fields  

Microsoft Academic Search

Enhanced biological control of weed seeds may improve sustainability of agricultural production. Biological control due to seed predation may be higher in organic fields because organic production generally supports more seed predators. To investigate such a difference, weed seed predation was studied in autumn in eight organic and eight conventional mixed cropping fields in New Zealand. Predation rates were estimated

S. Navntoft; S. D. Wratten; K. Kristensen; P. Esbjerg

2009-01-01

368

Genetic Influences on the Seed Yielding Ability of Carrot Hybrids  

Technology Transfer Automated Retrieval System (TEKTRAN)

Carrot seed production characteristics of four different threeway carrot hybrids were evaluated over three years during seed production from transplanted roots in Madison, Wisconsin. Components of seed yielding ability and plant architecture were measured. Both the male sterile seed parent and inbr...

369

Phytotoxicity of mustard seed meals alone and in combinations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mustard seed meal is produced when oil is extracted from brassicaceous seeds. The high glucosinolate content of these seed meals makes them of interest as management agents for weeds and soilborne pathogens. Previous studies indicated that seed meals from Brassica juncea and Sinapis alba are nemat...

370

ESTABLISHING WYOMING BIG SAGEBRUSH SEED ORCHARDS ON RECLAIMED MINE LAND  

Technology Transfer Automated Retrieval System (TEKTRAN)

Reclaimed mined lands often have restricted public access, a situation that could encourage sagebrush seed growers to invest in methods for increasing seed production and seed purity and quality. I tested the agronomic benefit of 2 seeding methods, fabric mulch, and a cross-linked polyacrylamide pol...

371

Thieving rodents as substitute dispersers of megafaunal seeds  

PubMed Central

The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatter-hoarding rodents has facilitated the persistence of these large-seeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each other’s buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees. PMID:22802644

Jansen, Patrick A.; Hirsch, Ben T.; Emsens, Willem-Jan; Zamora-Gutierrez, Veronica; Wikelski, Martin; Kays, Roland

2012-01-01

372

7 CFR 201.49 - Other crop seed.  

Code of Federal Regulations, 2010 CFR

...than the kind(s) and variety(ies) included in the pure seed) shall be considered other crop seeds, unless recognized as weed seeds by applicable laws, or regulations, or by general usage. All interpretations and definitions for “pure seed” in §...

2010-01-01

373

Radish (Raphanus sativus) seed size affects germination response to coumarin  

Technology Transfer Automated Retrieval System (TEKTRAN)

The inhibition of seed germination by an allelochemical is generally greater in small seeds than in large seeds. Studies reporting these results used a large number of plant species that varied in seed size, which might have introduced differences in germination characteristics or various parameter...

374

Strategies of seed dispersal and germination in plants inhabiting deserts  

Microsoft Academic Search

Massive seed consumption is typical in many deserts. The “escape” or “protection” strategies of seed dispersal are important, as they prevent massive seed consumption. The more extreme the desert, the more unpredictable the low amounts and distribution of the rains as well as the beginning and length of the season or seasons with rains. Seeds, which have the highest resistance

Yitzchak Gutterman; Jacob Blaustein

1994-01-01

375

Hormonal and molecular events during seed dormancy release and germination  

E-print Network

Hormonal and molecular events during seed dormancy release and germination Gerhard Leubner on Seeds, Salamanca, Spain, 12-16 May 2002 Symposium Seed Dormancy and Germination #12;Leubner-Metzger (2003) - page 2 Introduction Seed germination of species with 'coat-imposed' dormancy is determined

Leubner, Gerhard

376

Running head: Transcriptional Dynamics in Two Seed Compartments Corresponding author  

E-print Network

Dynamics of Two Seed Compartments with Opposing Roles in Arabidopsis Seed Germination Authors: Bas J seed germination which are separated by testa rupture. #12;3 Footnotes: Financial sources: This work Dekkers, bas.dekkers@wur.nl #12;4 ABSTRACT Seed germination is a critical stage in the plant life cycle

Leubner, Gerhard

377

Quality of guayule seeds separated by physical attributes  

Microsoft Academic Search

Guayule (Parthenium argentatum Gray) is being developed as a new commercial crop to be grown in arid and semiarid regions. Guayule stands are presently established using transplants; however, establishment by direct-seeding would reduce costs and make production more economical. A major difficulty in field establishment by direct-seeding is the variation in the quality of guayule seeds. Guayule seeds vary greatly

Marçal Henrique Amici Jorge; Maren E. Veatch-Blohm; Dennis T. Ray

2007-01-01

378

Tomato Tasting Seed Source List 2011 Snyder Farm Observation Trial  

E-print Network

Tomato Tasting Seed Source List 2011 Snyder Farm Observation Trial Seed Source*Tomato Variety Beefsteak/Extra Large Tomato Growers Supply CoAnanas Noir Pinetree Garden SeedsBig Rainbow Tomato Growers Supply CoBoondocks StokesBrandywine Tomato Growers Supply CoChurch Seed Savers Exchange

Goodman, Robert M.

379

Note: Seed for Moreton tomato are available in packets (35 seeds) from http://www.njfarmfresh.rutgers.edu/ JerseyTomato.html. Bulk Moreton seed available from Harris Seed http://www.harrisseeds.com.  

E-print Network

Note: Seed for Moreton tomato are available in packets (35 seeds) from http://www.njfarmfresh.rutgers.edu/ JerseyTomato.html. Bulk Moreton seed available from Harris Seed http://www.harrisseeds.com. Shipping Tomato Point of Purchase Material 2012 Order Form for Retailers Plant labels, 5 X 7 bench cards and sign

Goodman, Robert M.

380

Mustard Seed Meal suppresses Weeds in Potato and Peppermint  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seed meal is a co-product remaining after pressing mustard seed to remove the oil. Seed meals containing high glucosinolates have been reported to have herbicidal activity. Weed suppression with seed meal of Sinapis alba, variety Ida Gold was evaluated in field trials on potatoes and peppermint in ...

381

SEED GERMINATION AND VIABILITY OF WYOMING SAGEBRUSH IN NORTHERN NEVADA  

Microsoft Academic Search

SUMMARY Seed size and germination behavior affect performance of early seedlings. The purpose of this study was to investigate rela- tionships between seed size and germination percentage, germina- tion rate, time course of germination and seed viability in Wyo- ming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young). Working hypotheses were: 1) for single seeds, germination percentages and rates

Carlos A. Busso; Mónica Mazzola; Barry L. Perryman

2005-01-01

382

Effects of Fertilisers on Seed Germination in New Zealand  

Microsoft Academic Search

This paper uses data from a series of local field and glasshouse studies to highlight the main issues associated with fertilisers causing germination damage to seed. When fertiliser was placed in close contact with seed either through a conventional drill or when placed on top of seed in the glasshouse, in general small seed was more predisposed to germination damage

M. D. Craighead

383

Graph Based Crawler Seed Selection Shuyi Zheng1  

E-print Network

Graph Based Crawler Seed Selection Shuyi Zheng1 Pavel Dmitriev2 C. Lee Giles1 1 Pennsylvania State and explores the problem of seed se- lection in a web-scale crawler. We argue that seed selec- tion is not a trivial but very important problem. Selecting proper seeds can increase the number of pages a crawler

Giles, C. Lee

384

Frequency selective infrared sensors  

DOEpatents

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2013-05-28

385

Frequency selective infrared sensors  

DOEpatents

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2014-11-25

386

Role of Seed Coat in Imbibing Soybean Seeds Observed by Micro-magnetic Resonance Imaging  

PubMed Central

Background and Aims Imbibition of Japanese soybean (Glycine max) cultivars was studied using micro-magnetic resonance imaging (MRI) in order to elucidate the mechanism of soaking injury and the protective role of the seed coat. Methods Time-lapse images during water uptake were acquired by the single-point imaging (SPI) method at 15-min intervals, for 20 h in the dry seed with seed coat, and for 2 h in seeds with the seed coat removed. The technique visualized water migration within the testa and demonstrated the distortion associated with cotyledon swelling during the very early stages of water uptake. Key Results Water soon appeared in the testa and went around the dorsal surface of the seed from near the raphe, then migrated to the hilum region. An obvious protrusion was noted when water reached the hypocotyl and the radicle, followed by swelling of the cotyledons. A convex area was observed around the raphe with the enlargement of the seed. Water was always incorporated into the cotyledons from the abaxial surfaces, leading to swelling and generating a large air space between the adaxial surfaces. Water uptake greatly slowed, and the internal structures, veins and oil-accumulating tissues in the cotyledons developed after the seed stopped expanding. When the testa was removed from the dry seeds before imbibition, the cotyledons were severely damaged within 1·5 h of water uptake. Conclusions The activation of the water channel seemed unnecessary for water entry into soybean seeds, and the testa rapidly swelled with steeping in water. However, the testa did not regulate the water incorporation in itself, but rather the rate at which water encountered the hypocotyl, the radicle, and the cotyledons through the inner layer of the seed coat, and thus prevented the destruction of the seed tissues at the beginning of imbibition. PMID:18565982

Koizumi, Mika; Kikuchi, Kaori; Isobe, Seiichiro; Ishida, Nobuaki; Naito, Shigehiro; Kano, Hiromi

2008-01-01

387

Increasing phosphorus concentration in seed of annual pasture legume species increases herbage and seed yields  

Microsoft Academic Search

In glasshouse experiments with low levels of soil applied phosphorus (P), yields of four annual pasture legumes (Medicago polymorpha, Trifolium subterraneum, T. balansae, Ornithopus compressus) increased with increasing P concentration in the seed.\\u000a \\u000a In a further experiment, M. polymorpha cv. Serena was grown at the same plant density from seed of two P concentrations and two seed sizes when two

M. D. A. Bolland; B. H. Paynter

1990-01-01

388

Allometric allocation in fruit and seed packaging conditions the conflict among selective pressures on seed size  

Microsoft Academic Search

Selective pressures on seed size could vary among the different stages of plant life cycles, so no simple relation could explain\\u000a a priori its evolution. Here, we determined the relationships between seed size and two fitness components—seed dispersal and survival\\u000a from predation—in a bird-dispersed tree, Crataegus monogyna. We interpret these relationships in relation to the patterns of mass allocation to

Isabel Martínez; Daniel García; José Ramón Obeso

2007-01-01

389

Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: Where do all the seeds go?  

USGS Publications Warehouse

Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert-sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application. ?? 2010 Society for Ecological Restoration International.

DeFalco, L.A.; Esque, T.C.; Nicklas, M.B.; Kane, J.M.

2012-01-01

390

The roles of seed mass and persistent seed banks in gap colonisation in grassland  

Microsoft Academic Search

Gaps in grassland created by animals are often sites for species regeneration. The persistent seed banks of ant-hills and\\u000a surrounding soils in a calcareous grassland in southern Britain were compared and analysed in terms of seed mass and longevity.\\u000a The relative abundance of species on ant-hills compared to the pasture was highly correlated with seed abundance in ant-hill\\u000a soil. The

Timothy John King

2007-01-01

391

Effect of GA3 Treatment on Seed Development and Seed-Related Gene Expression in Grape  

PubMed Central

Background The phytohormone gibberellic acid (GA3) is widely used in the table grape industry to induce seedlessness in seeded varieties. However, there is a paucity of information concerning the mechanisms by which GAs induce seedlessness in grapes. Methodology/Principal Findings In an effort to systematically analyze the cause of this GA3-induced seed abortion, we conducted an in depth characterization of two seeded grape cultivars (‘Kyoho’ and ‘Red Globe’), along with a seedless cultivar (‘Thompson Seedless’), following treatment with GA3. In a similar fashion to the seedless control, which exhibited GA3-induced abortion of the seeds 9 days after full bloom (DAF), both ‘Kyoho’ and ‘Red Globe’ seeded varieties exhibited complete abortion of the seeds 15 DAF when treated with GA3. Morphological analyses indicated that while fertilization appeared to occur normally following GA3 treatment, as well as in the untreated seedless control cultivar, seed growth eventually ceased. In addition, we found that GA3 application had an effect on redox homeostasis, which could potentially cause cell damage and subsequent seed abortion. Furthermore, we carried out an analysis of antioxidant enzyme activities, as well as transcript levels from various genes believed to be involved in seed development, and found several differences between GA3-treated and untreated controls. Conclusion Therefore, it seems that the mechanisms driving GA3-induced seedlessness are similar in both seeded and seedless cultivars, and that the observed abortion of seeds may result at least in part from a GA3-induced increase in cell damage caused by reactive oxygen species, a decrease in antioxidant enzymatic activities, and an alteration of the expression of genes related to seed development. PMID:24224035

Cheng, Chenxia; Xu, Xiaozhao; Singer, Stacy D.; Li, Jun; Zhang, Hongjing; Gao, Min; Wang, Li; Song, Junyang; Wang, Xiping

2013-01-01

392

Gastropod Seed Dispersal: An Invasive Slug Destroys Far More Seeds in Its Gut than Native Gastropods  

PubMed Central

Seed dispersal is one of the most important mechanisms shaping biodiversity, and animals are one of the key dispersal vectors. Animal seed dispersal can directly or indirectly be altered by invasive organisms through the establishment of new or the disruption of existing seed dispersal interactions. So far it is known for a few gastropod species that they ingest and defecate viable plant seeds and consequently act as seed dispersers, referred to as gastropodochory. In a multi-species experiment, consisting of five different plant species and four different gastropod species, we tested with a fully crossed design whether gastropodochory is a general mechanism across native gastropod species, and whether it is altered by the invasive alien slug species Arion lusitanicus. Specifically, we hypothesized that a) native gastropod species consume the seeds from all tested plant species in equal numbers (have no preference), b) the voracious invasive alien slug A. lusitanicus – similarly to its herbivore behaviour – consumes a higher amount of seeds than native gastropods, and that c) seed viability is equal among different gastropod species after gut passage. As expected all tested gastropod species consumed all tested plant species. Against our expectation there was a difference in the amount of consumed seeds, with the largest and native mollusk Helix pomatia consuming most seeds, followed by the invasive slug and the other gastropods. Seed damage and germination rates did not differ after gut passage through different native species, but seed damage was significantly higher after gut passage through the invasive slug A. lusitanicus, and their germination rates were significantly reduced. PMID:24086477

Blattmann, Tamara; Boch, Steffen; Türke, Manfred; Knop, Eva

2013-01-01

393

A low jitter single frequency Q-switched laser from solid state to optical fiber configuration  

NASA Astrophysics Data System (ADS)

This paper will get to the bottom of the mechanism of a superior inject seeding technology, and take it even further, from the solid state laser into the fiber laser configuration. This low jitter, single frequency Q-switched solid state laser with precisely controllable firing time was realized, developed and reported previously, in which the oscillator can output energy of near 100 mJ and the master oscillator power amplifier (MOPA) reaches the output energy of 300 mJ, operating at a wavelength of 1064 nm, with a pulse width of 10 ns and in near single transversal mode. Comparing two existing commercial techniques, ramp-and-fire and pulse-to-pulse buildup time reduction, this report presents a full understanding of using a CW transformed injection seeding method in which this technique is immune to mechanical vibration or thermal expansion, and it is able to precisely control the high peak energy launching time within a nanosecond jitter and achieve single frequency operation at the same time. It is carefully observed that the CW seeding mechanism is similar but not equivalent to a pulsed seeding with pulse width shorter or equal to the ring cavity length. The advantage of the realized regime is that in stable laser operation there is no need to adjust the slave cavity length to match the seeded light longitudinal mode. Therefore, the extremely strict mechanical requirement can be relaxed. It is found that the slave laser frequency follows exactly to the injected seeded laser's frequency which can also provide frequency tuning, control and locking.

Wu, Frank F.

2013-03-01

394

Seed Dispersers, Seed Predators, and Browsers Act Synergistically as Biotic Filters in a Mosaic Landscape  

PubMed Central

In this study, we analize the functional influence of animals on the plants they interact with in a mediterranean mountain. We hypothesise that seed dispersers, seed predators, and browsers can act as biotic filters for plant communities. We analyse the combined effects of mutualistic (seed dispersal) and antagonistic (seed predation, herbivory) animal interactions in a mosaic landscape of Mediterranean mountains, basing our results on observational and experimental field. Most of the dispersed seeds came from tree species, whereas the population of saplings was composed predominantly of zoochorous shrub species. Seed predators preferentially consumed seeds from tree species, whereas seeds from the dominant fleshy-fruited shrubs had a higher probability of escaping these predators. The same pattern was repeated among the different landscape units by browsers, since they browsed selectively and far more intensely on tree-species saplings than on the surrounding shrubs. In synthesis, our work identifies the major biotic processes that appear to be favoring a community dominated by shrubs versus trees because seed dispersers, predators, and herbivores together favored shrub dispersal and establishment versus trees. PMID:25233342

Zamora, Regino; Matías, Luis

2014-01-01

395

Vacuum Seed Sowing Manifold: a novel device for high-throughput sowing of Arabidopsis seeds  

PubMed Central

The small size of Arabidopsis provides both opportunities and difficulties for laboratory research. Large numbers of plants can be grown in a relatively small area making it easy to observe and investigate interesting phenotypes. Conversely, their small size can also make it difficult to obtain large quantities of tissue for investigation using modern molecular techniques. Sowing large numbers of their seed can overcome this; however, their small seed size makes this difficult. Here we present the Vacuum Seed Sowing Manifold (VSSM), a simple device that can be printed using a 3D printer and provides a new high throughput method to sow large numbers of seeds at a range of densities. PMID:24148867

2013-01-01

396

Timing of fire relative to seed development controls availability of non-serotinous aerial seed banks  

NASA Astrophysics Data System (ADS)

The existence of non-serotinous, non-sprouting species in fire regimes where serotiny confers an adaptive advantage is puzzling, particularly when these species recruit poorly from soil seed banks or from burn edges. In this paper, white spruce (Picea glauca (Moench) Voss) was used to show that the timing of fire relative to seed development can control aerial seed bank availability for non-serotinous species. To estimate seed survival in closed cones during crown fires, cone heating was simulated using a one-dimensional conduction model implemented in a computational fluid dynamics (Navier-Stokes) fire spread model. To quantify the area burned when germinable seed would be contained in closed cones, empirical fire occurrence and seed development (germinability and cone opening) data were compared for multiple locations across the white spruce range. Approximately 12% of cones contained viable seed following crown fire simulations (0.072 m s-1 mean spread rate; 9147 kW m-1 mean intensity), and roughly half of the historical area burned resulted from fires that occurred when closed cones would contain germinable seed. Post-fire recruitment from in situ aerial seed banks can occur for non-serotinous species, and may be an important cause of their existence in fire regimes to which they otherwise seem poorly suited.

Michaletz, S. T.; Johnson, E. A.; Mell, W. E.; Greene, D. F.

2012-11-01

397

The functional response of a hoarding seed predator to mast seeding.  

PubMed

Mast seeding involves the episodic and synchronous production of large seed crops by perennial plants. The predator satiation hypothesis proposes that mast seeding maximizes seed escape because seed predators consume a decreasing proportion of available seeds with increasing seed production. However, the seed escape benefits of masting depend not only on whether predators are satiated at high levels of seed production, but also on the shape of their functional response (type II vs. type III), and the actual proportion of available seeds that they consume at different levels of seed production. North American red squirrels (Tamiasciurus hudsonicus) are the primary vertebrate predator of white spruce (Picea glauca) mast seed crops in many boreal regions because they hoard unopened cones in underground locations, preempting the normal sequence of cone opening, seed dispersal, and seed germination. We document the functional response of cone-hoarding by red squirrels across three non-mast years and one mast year by estimating the number of cones present in the territories of individual red squirrels and the proportion of these cones that they hoarded each autumn. Even though red squirrels are not constrained by the ingestive and on-body (fat reserves) energy reserve limitations experienced by animals that consume seeds directly, most squirrels hoarded < 10% of the cones present on their territories under mast conditions. Cone availability during non-mast years also reached levels that satiated the hoarding activity of red squirrels; however, this occurred only on the highest-quality territories. Squirrels switched to mushroom-hoarding when cone production was low and mushrooms were abundant. This resulted in type III functional response whereby the proportional harvest of cones was highest at levels of cone availability that were intermediate within non-mast years. Overall, more cones escaped squirrel cone-hoarding during a mast event than when cone production was low in non-mast years, which supports the predator satiation hypothesis. However, the highly variable seed escape in non-mast years may help to explain why all spruce cone production is not concentrated into fewer, larger, mast years. PMID:20957961

Fletcher, Quinn E; Boutin, Stan; Lane, Jeffrey E; LaMontagne, Jalene M; McAdam, Andrew G; Krebs, Charles J; Humphries, Murray M

2010-09-01

398

Landscape-scale eco-evolutionary dynamics: selection by seed predators and fire determine a major reproductive strategy.  

PubMed

Recent work in model systems has demonstrated significant effects of rapid evolutionary change on ecological processes (eco-evolutionary dynamics). Fewer studies have addressed whether eco-evolutionary dynamics structure natural ecosystems. We investigated variation in the frequency of serotiny in lodgepole pine (Pinus contorta), a widespread species in which postfire seedling density and ecosystem structure are largely determined by serotiny. Serotiny, the retention of mature seeds in cones in a canopy seed bank, is thought to be an adaptation for stand-replacing fire, but less attention has been paid to the potential selective effects of seed predation on serotiny. We hypothesized that spatial variation in percentage serotiny in lodgepole pine forests results from an eco-evolutionary dynamic where the local level of serotiny depends on the relative strengths of conflicting directional selection from fire (favoring serotiny) and seed predation (favoring cones that open at maturity). We measured percentage serotiny, the abundance of American red squirrels (Tamiasciurus hudsonicus; the primary pre-dispersal seed predator of lodgepole pine), and several measures of forest structure in Yellowstone National Park, USA. Fire frequency strongly predicted the frequency of serotiny, a pattern that is well-supported in the literature. At sites with high fire frequency (return intervals of -135-185 years) where fire favors increased serotiny, squirrel abundance was negatively associated with serotiny, suggesting that selection from predation can overwhelm selection from fire when squirrels are abundant. At sites with low fire frequency (return intervals of -280-310 years), serotiny was nearly universally uncommon (< 10%). Finally, forest structure strongly predicted squirrel density independently of serotiny, and serotiny provided no additional explanatory power, suggesting that the correlation is caused by selection against serotiny exerted by squirrels, rather than squirrels responding to variation in percentage serotiny. PMID:23923494

Talluto, Matt V; Benkman, Craig W

2013-06-01

399

Radio frequency detection assembly and method for detecting radio frequencies  

DOEpatents

A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

Cown, Steven H. (Rigby, ID); Derr, Kurt Warren (Idaho Falls, ID)

2010-03-16

400

Global changes in DNA methylation in seeds and seedlings of Pyrus communis after seed desiccation and storage.  

PubMed

The effects of storage and deep desiccation on structural changes of DNA in orthodox seeds are poorly characterized. In this study we analyzed the 5-methylcytosine (m(5)C) global content of DNA isolated from seeds of common pear (Pyrus communis L.) that had been subjected to extreme desiccation, and the seedlings derived from these seeds. Germination and seedling emergence tests were applied to determine seed viability after their desiccation. In parallel, analysis of the global content of m(5)C in dried seeds and DNA of seedlings obtained from such seeds was performed with a 2D TLC method. Desiccation of fresh seeds to 5.3% moisture content (mc) resulted in a slight reduction of DNA methylation, whereas severe desiccation down to 2-3% mc increased DNA methylation. Strong desiccation of seeds resulted in the subsequent generation of seedlings of shorter height. A 1-year period of seed storage induced a significant increase in the level of DNA methylation in seeds. It is possible that alterations in the m(5)C content of DNA in strongly desiccated pear seeds reflect a reaction of desiccation-tolerant (orthodox) seeds to severe desiccation. Epigenetic changes were observed not only in severely desiccated seeds but also in 3-month old seedlings obtained from these seeds. With regard to seed storage practices, epigenetic assessment could be used by gene banks for early detection of structural changes in the DNA of stored seeds. PMID:23940629

Michalak, Marcin; Barciszewska, Miros?awa Z; Barciszewski, Jan; Plitta, Beata P; Chmielarz, Pawe?

2013-01-01

401

Spatial dynamics of Ilex aquifolium populations seed dispersal and seed bank: understanding the first steps of regeneration  

Microsoft Academic Search

The objective of this study was to analyse quantitatively the spatial distribution of holly (Ilex aquifolium L.) seed rain and seed bank, and to detect the relationships between these consecutive processes. We measured seed dispersal by birds and fallen fruits, and also density and viability of seed bank in two Ilex populations in central Spain. Analysis was made distinguishing the

Sagrario Arrieta; Francisco Suárez

2005-01-01

402

Effects of Gut Passage, Feces, and Seed Handling on Latency and Rate of Germination in Seeds Consumed by  

E-print Network

Effects of Gut Passage, Feces, and Seed Handling on Latency and Rate of Germination in Seeds, and germination rates of 18 species consumed by capuchins. For five of the most commonly swallowed seed species, we determined germination rates and average time to germination (latency) for seeds ingested

Fedigan, Linda M.

403

Inhibitory effect of myrigalone A on seed germination 1 Myrigalone A inhibits Lepidium sativum seed germination by interference with  

E-print Network

Inhibitory effect of myrigalone A on seed germination 1 Myrigalone A inhibits Lepidium sativum seed herbicide) and different terpenes on the endosperm rupture of germinating Lepidium sativum seeds in the figure) and sulcotrione. (B) Seedlings grown from seeds germinated in the presence of the herbicide

Leubner, Gerhard

404

Shaping metal nanocrystals through epitaxial seeded growth  

SciTech Connect

Morphological control of nanocrystals has becomeincreasingly important, as many of their physical and chemical propertiesare highly shape-dependent. Nanocrystal shape control for both single andmultiple material systems, however, remains fairly empirical andchallenging. New methods need to be explored for the rational syntheticdesign of heterostructures with controlled morphology. Overgrowth of adifferent material on well-faceted seeds, for example, allows for the useof the defined seed morphology to control nucleation and growth of thesecondary structure. Here, we have used highly faceted cubic Pt seeds todirect the epitaxial overgrowth of a secondary metal. We demonstrate thisconcept with lattice matched Pd to produce conformal shape-controlledcore-shell particles, and then extend it to lattice mismatched Au to giveanisotropic growth. Seeding with faceted nanocrystals may havesignificant potential towards the development of shape-controlledheterostructures with defined interfaces.

Habas, Susan E.; Lee, Hyunjoo; Radmilovic, Velimir; Somorjai,Gabor A.; Yang, Peidong

2008-02-17

405

Pollen management for intensive seed orchard production.  

PubMed

Artificially increasing pollen supply (supplemental mass pollination (SMP)) to conifer seed orchards has the potential to increase seed yields and improve the genetic worth of seed crops that would otherwise suffer from the detrimental effects of pollen contamination and unbalanced paternal contribution. However, success rates, measured as the proportion of seed fertilized by SMP, have been low. This review examines the concepts underlying SMP and presents data for two SMP field trials with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and white/Engelmann spruce (Picea glauca (Moench) Voss, Picea engelmannii Parry ex Engelm.). The trial results are discussed with respect to pollen fertility, pollination technique, and competing pollen cloud density. I also summarize methods for ensuring the successful handling of pollen ex situ. PMID:14965935

Webber, Joe E.

1995-01-01

406

Seeding Coherent Radiation Sources with Sawtooth Modulation  

SciTech Connect

Seed radiation sources have the ability to increase longitudinal coherence, decrease saturation lengths, and improve performance of tapering, polarization control and other FEL features. Typically, seeding schemes start with a simple sinusoidal modulation, which is manipulated to provide bunching at a high harmonic of the original wavelength. In this paper, we consider seeding from sawtooth modulations. The sawtooth creates a clean phase space structure, providing a maximal bunching factor without the need for an FEL interaction. While a pure sawtooth modulation is a theoretical construct, it is possible to approach the waveform by combining two or more of the composite wavelengths. We give examples of sawtooth seeding for HGHG, EEHG and other schemes, and note that the sawtooth modulation may aid in suppression of the microbunching instability.

Ratner, Daniel; Chao, Alex; /SLAC

2012-03-28

407

Effects of Air Temperature on Seed Germination  

NSDL National Science Digital Library

This activity begins as a classroom investigation, but may extend to a field investigation where students will determine the effects of air temperature on seed germination. This is accomplished by developing investigative questions, recording, and analyzing data.

Amy MacArthur

408

Respiratory Transition during Seed Germination 1  

PubMed Central

Experiments with germinating seeds of Wayne soybean (Glycine max Merr.) show that between the 4th and the 8th hour of germination, respiration experiences a transition from predominantly “alternate” respiration, which is sensitive to salicylhydroxamic acid, to a cyanide-sensitive respiration. The dependence of early germination stages on alternate respiration is reflected in several types of seed functions, including subsequent root growth rate, chlorophyll synthesis, and germination itself. The early period of germination is shown to require a normal O2 tension, which is no longer a requirement at later stages. The changing sensitivity to cyanide and to salicylhydroxamic acid is found to be common to seven different types of germinating seeds. It is proposed that the alternate pathway of respiration provides something essential for the completion of the earliest stages of seed germination. PMID:16659465

Yentur, Semahat; Leopold, A. Carl

1976-01-01

409

MHD seed recovery/regeneration, Phase 2  

SciTech Connect

This report is divided into the following tasks: design, refurbish, operate potassium formate ( backend'') system; design, construct, operate the calcium formate production POC ( Frontend'') unit; and Western seed (K carbonate, sulfate) studies. 5 figs.

Not Available

1993-01-01

410

Automatic Brachytherapy Seed Placement Under MRI Guidance  

PubMed Central

The paper presents a robotic method of performing low dose rate prostate brachytherapy under magnetic resonance imaging (MRI) guidance. The design and operation of a fully automated MR compatible seed injector is presented. This is used with the MrBot robot for transperineal percutaneous prostate access. A new image-registration marker and algorithms are also presented. The system is integrated and tested with a 3T MRI scanner. Tests compare three different registration methods, assess the precision of performing automated seed deployment, and use the seeds to assess the accuracy of needle targeting under image guidance. Under the ideal conditions of the in vitro experiments, results show outstanding image-guided needle and seed placement accuracy. PMID:17694871

Patriciu, Alexandru; Petrisor, Doru; Muntener, Michael; Mazilu, Dumitru; Schär, Michael; Stoianovici, Dan

2011-01-01

411

Respiration in dormant and non-dormant bitterbrush seeds  

Microsoft Academic Search

Bitterbrush (Purshia tridentata dc.) seed dormancy is not understood but may result from a metabolic block by a chemical inhibitor. To determine whether dormancy affects seed respiration, we compared CO2evolution from individual imbibed dormant and non-dormant seeds and from germinating seeds, using Fourier transform infrared photoacoustic spectroscopy. We found CO2evolution did not differ between dormant and non-dormant seeds, and that

D. T. Booth; S. Sowa

2001-01-01

412

Germination of 151-year old Acacia spp. seeds  

Microsoft Academic Search

A collection of seeds from five Acacia species was made in Egypt in 1856. Since then, the seeds have been stored at room temperature in different Swedish museums.\\u000a Due to the extreme longevity within the seeds of Acacia and related species, germination tests were performed on the now 151-year old seed. Seeds of two of the five species tested\\u000a germinated.

Matti W. Leino; Johan Edqvist

2010-01-01

413

Role of H2O2 in pea seed germination  

PubMed Central

The imbibition of pea seeds with hydrogen peroxide (H2O2) increased the germination as well as the seedling growth, producing an invigoration of the seeds. We propose that H2O2 could acts as signaling molecule in the beginning of seed germination involving specific changes at proteomic, transcriptomic and hormonal levels. These findings have practical implication in the context of seed priming technologies to invigorate low vigour seeds. PMID:22415047

Barba-Espín, Gregorio; Hernández, José Antonio; Diaz-Vivancos, Pedro

2012-01-01

414

Postfire seed bank dynamics in semiarid grasslands  

Microsoft Academic Search

We evaluated the combined effects of fire after drought on the seed bank composition and its role in the postfire recovery\\u000a of NW Patagonia grasslands. During three years, we monitored the seed bank and the aboveground vegetation. Species were arranged\\u000a in functional groups and Detrended Correspondence Analysis was used to separate sites according to species and functional\\u000a groups. Similarity between

S. Gonzalez; L. Ghermandi

2008-01-01

415

Canopy seed storage in woody plants  

Microsoft Academic Search

The retention of seeds in the plant canopy for one to 30 years or more is termed serotiny. It is well represented floristically\\u000a and physiognomically in fire-prone, nutrient-poor and seasonally-dry sclerophyll vegetation in Australia, and to a lesser\\u000a extent, South Africa followed by North America. While the seed-storing structures vary greatly, all will release their propagules\\u000a following exposure to the

Byron B. Lamont; D. C. Le Maitre; R. M. Cowling; N. J. Enright

1991-01-01

416

Grass management for forage and seed production  

E-print Network

GRASS MANAGEMENT FOR FORAGE AND SEED PRODUCTION A Thesis by RICHARD JOHN HENDLER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1979 Major... Subject: Agronomy GRASS MANAGEMENT FOR FORAGE AND SEED PRODUCTION A Thesis by RICHARD JOHN HENDLER Approved as to style and content by: (Chairman of Committee) (Head of Department) (Member) Member) August 1979 ABSTRACT Grass Management...

Hendler, Richard John

2012-06-07

417

Seed germination ecology in southwestern Western Australia  

Microsoft Academic Search

Germination responses of species from the native plant communities of southwestern Western Australia can be related to syndromes\\u000a of life history, fire response, and seed storage, and also to factors related to environmental stress. The Mediterranean-type\\u000a climate of the region with periodic drought and recurrent fires affects the production of viable seeds in plants of limited\\u000a stature and rooting depth.

David T. Bell; Julie A. Plummer; Susan K. Taylor

1993-01-01

418

Promotion of seed germination by cyanide.  

PubMed

Potassium cyanide at 3 mum to 10 mm promotes germination of Amaranthus albus, Lactuca sativa, and Lepidium virginicum seeds. l-Cysteine hydrogen sulfide lyase, which catalyzes the reaction of HCN with l-cysteine to form beta-l cyanoalanine, is active in the seeds. beta-l-Cyanoalanine is the most effective of the 23 alpha-amino acids tested for promoting germination of A. albus seeds. Aspartate, which is produced by enzymatic hydrolysis of asparagine formed by hydrolysis from beta-cyanoalanine, is the second most effective of the 23 amino acids. Uptake of aspartate-4-(14)C is much lower than of cyanide.Radioactive tracer in K(14)CN shows uptake of about 1.5 mumoles of HCN per gram of A. albus and L. sativa seeds after 20 hours of imbibition. Extracts of the seeds gave high (14)C activity in beta-cyanoalanine, asparagine, and aspartate. The acid-hydrolyzed protein extract gave high activity only in aspartate. Tests were negative for free cyanide in the seed. Respiration of the seed is inhibited more than 75% by KCN and by KN(3) at 10 mm. Azide at greater than 1.0 mm inhibits the promotion of germination by cyanides. Neither 0.1 mm KCN nor KN(3) inhibit O(2) consumption, whereas lower concentrations promote germination. It is concluded that the high rate of utilization of cyanide in the reaction to form beta-l-cyanoalanine and the subsequent incorporation into protein limit any inhibition of oxygen consumption. The promotion of seed germination is substrate-limited by asparagine-aspartate, which is required for protein synthesis. PMID:16658492

Taylorson, R B; Hendricks, S B

1973-07-01

419

Promotion of Seed Germination by Cyanide  

PubMed Central

Potassium cyanide at 3 ?m to 10 mm promotes germination of Amaranthus albus, Lactuca sativa, and Lepidium virginicum seeds. l-Cysteine hydrogen sulfide lyase, which catalyzes the reaction of HCN with l-cysteine to form ?-l cyanoalanine, is active in the seeds. ?-l-Cyanoalanine is the most effective of the 23 ?-amino acids tested for promoting germination of A. albus seeds. Aspartate, which is produced by enzymatic hydrolysis of asparagine formed by hydrolysis from ?-cyanoalanine, is the second most effective of the 23 amino acids. Uptake of aspartate-4-14C is much lower than of cyanide. Radioactive tracer in K14CN shows uptake of about 1.5 ?moles of HCN per gram of A. albus and L. sativa seeds after 20 hours of imbibition. Extracts of the seeds gave high 14C activity in ?-cyanoalanine, asparagine, and aspartate. The acid-hydrolyzed protein extract gave high activity only in aspartate. Tests were negative for free cyanide in the seed. Respiration of the seed is inhibited more than 75% by KCN and by KN3 at 10 mm. Azide at greater than 1.0 mm inhibits the promotion of germination by cyanides. Neither 0.1 mm KCN nor KN3 inhibit O2 consumption, whereas lower concentrations promote germination. It is concluded that the high rate of utilization of cyanide in the reaction to form ?-l-cyanoalanine and the subsequent incorporation into protein limit any inhibition of oxygen consumption. The promotion of seed germination is substrate-limited by asparagine-aspartate, which is required for protein synthesis. PMID:16658492

Taylorson, R. B.; Hendricks, S. B.

1973-01-01

420

Seed extracts inhibiting protein synthesis in vitro.  

PubMed Central

Of 33 seed extracts examined, 12 inhibited protein synthesis in a rabbit reticulocyte lysate. This activity seems to be due to a protein, since (i) it was recovered with the (NH4)2SO4 precipitate, (ii) it was retained by dialysis membranes, and (iii) in all cases but one was destroyed by boiling. Only the extracts from the seeds of Adenia digitata and, to a lower extent, of Euonymus europaeus inhibited protein synthesis in intact cells. PMID:7378060

Gasperi-Campani, A; Barbieri, L; Morelli, P; Stirpe, F

1980-01-01

421

Chemopreventive activity of Ocimum sanctum seed oil  

Microsoft Academic Search

The seed oil of Ocimum sanctum was evaluated for chemopreventive activity against subcutaneously injected 20-methylcholanthrene induced-fibrosarcoma tumors in the thigh region of Swiss albino mice. Supplementation of maximal tolerated dose (100 ?l\\/kg body weight) of the oil significantly reduced 20-methylcholanthrene induced tumor incidence and tumor volume. The enhanced survival rate and delay in tumor incidence was observed in seed oil

Jai Prakash; S. K Gupta

2000-01-01

422

Phosphorus accumulation in Proteaceae seeds: a synthesis  

Microsoft Academic Search

The family Proteaceae dominates the nutrient-poor, Mediterranean-climate floristic regions of southwestern Australia (SWA)\\u000a and the Cape of South Africa. It is well-recognised that mediterranean Proteaceae have comparatively large seeds that are\\u000a enriched with phosphorus (P), stored mainly as salts of phytic acid in protein globoids. Seed P can contribute up to 48% of\\u000a the total aboveground P, with the fraction

Philip K. Groom; Byron B. Lamont

2010-01-01

423

Seed germination characteristics of Halogeton glomeratus  

Microsoft Academic Search

Halogeton glomeratus (Bieb.) C.A. Mey, an annual forb in the family Chenopodiaceae, is widely distributed in the inland salt deserts of western North America. Experiments were conducted to determine the effects of NaCl and temperature on seed germination and the recovery of germination responses after transfer to distilled water. Seeds of H. glomeratus were germinated at various temperature regimes (5-15°C,

M. Ajmal Khan; Bilquees Gul; Darrell J. Weber

2001-01-01

424

Protein syntehsis during soybean seed maturation  

SciTech Connect

The authors previous work has demonstrated that physiological and biochemical changes specifically associated with soybean seed maturation can be separated from events associated with seed development. The objective of this study was to determine if soybean seed metabolism is altered during maturation drying at the level of protein synthesis. Seed harvested 35 days after flowering (0% seedling growth) were induced to mature (100% seedling growth) through controlled dehydration. Proteins labeled with (/sup 35/S)-methionine were extracted and analyzed by 1-D PAGE coupled with autoradiography and densitometry. Results show a 31 kD and 128 kD polypeptide synthesized de novo during dehydration and precocious maturation. The same two polypeptides are synthesized during natural dehydration and maturation (>60 days after flowering). Furthermore, these polypeptides persist during rehydration and germination of both precociously and naturally matured seed, but specifically disappear during early seedling growth. The authors are currently investigating the role of protein synthesis during soybean seed maturation and if it is required for establishment of a soybean seedling.

Rosenberg, L.A.; Rinne, R.W.

1987-04-01

425

Plants grow better if seeds see green  

NASA Astrophysics Data System (ADS)

We report on the response of dry plant seeds to their irradiation with intense green light applied at biostimulatory doses. Red and near-infrared light delivered by lasers or arrays of light emitting diodes applied at such doses have been shown previously by us to have effects on mammalian cells. Effects include cell proliferation and elevation of cell vitality, and have practical applications in various biomedical fields. Growth processes induced by photoreceptor stimulation (phytochromes and cryptochromes) in plant seeds with green light were described so far only for imbibed seeds. In this paper, we show that irradiation of dry cress, radish and carrot seeds with intense green light (laser or arrays of light emitting diodes), applied at biostimulatory doses, resulted in a significant increase in biomass—14, 26, and 71 days after seeding, respectively. In the case of radish and carrot, the irradiation led to important changes in the root-to-foliage surface ratio. Seeds with a potential to grant growth acceleration could be of special interest in agricultural applications, and could even compensate for shorter growth seasons caused by climate change.

Sommer, Andrei P.; Franke, Ralf-Peter

2006-07-01

426

Germination Response of MR 219 Rice Variety to Different Exposure Times and Periods of 2450?MHz Microwave Frequency  

PubMed Central

Germination is a key process in plants' phenological cycles. Accelerating this process could lead to improvment of the seedling growth as well as the cultivation efficiency. To achieve this, the effect of microwave frequency on the germination of rice seeds was examined. The physiological feedbacks of the MR 219 rice variety in terms of seed germination rate (GR), germination percentage (GP), and mean germination time (MGT) were analyzed by exposing its seeds to 2450?MHz of microwave frequency for one, four, seven, and ten hours. It was revealed that exposing the seeds to the microwave frequency for 10 hours resulted in the highest GP. This treatment led to 100% of germination after three days with a mean germination time of 2.1 days. Although the other exposure times of microwave frequency caused the moderate effects on germination with a GPa3 ranged from 93% to 98%, they failed to reduce the MGTa3. The results showed that ten-hour exposure times of microwave frequency for six days significantly facilitated and improved the germination indices (primary shoot and root length). Therefore, the technique is expected to benefit the improvement of rice seed germination considering its simplicity and efficacy in increasing the germination percentage and rate as well as the primary shoot and root length without causing any environmental toxicity. PMID:24307869

Valdiani, Alireza; Maziah, Mahmood; Mohsenkhah, Mohammad

2013-01-01

427

The need for a supply of high quality organic vegetable seeds  

Microsoft Academic Search

Production of high quality organic vegetable seeds encounters several challenges. Research is performed to support seed companies in producing vigorous and healthy organic vegetable seeds. Examples are provided with respect to research on seed vigour, determining critical control points to avoid disease transmission to the seeds, seed treatments with natu-ral compounds, new seed sorting techniques and enhancement of the natural

S. P. C. Groot; H. Jalink; C. Kromphardt; H. J. Krauthausen; S. J. Roberts; S. A. J. Wright; Wolf van der J. M; Bulk van den R. W; F. Tinivella; M. L. Guliino; M. Wikstrom; S. Werner; E. Koch

2006-01-01

428

Identification of the Infection Route of a Fusarium Seed Pathogen into Nondormant Bromus tectorum Seeds.  

PubMed

ABSTRACT The genus Fusarium has a wide host range and causes many different forms of plant disease. These include seed rot and seedling blight diseases of cultivated plants. The diseases caused by Fusarium on wild plants are less well-known. In this study, we examined disease development caused by Fusarium sp. n on nondormant seeds of the important rangeland weed Bromus tectorum as part of broader studies of the phenomenon of stand failure or "die-off" in this annual grass. We previously isolated an undescribed species in the F. tricinctum species complex from die-off soils and showed that it is pathogenic on seeds. It can cause high mortality of nondormant B. tectorum seeds, especially under conditions of water stress, but rarely attacks dormant seeds. In this study, we used scanning electron microscopy (SEM) to investigate the mode of attack used by this pathogen. Nondormant B. tectorum seeds (i.e., florets containing caryopses) were inoculated with isolate Skull C1 macroconidia. Seeds were then exposed to water stress conditions (-1.5 MPa) for 7 days and then transferred to free water. Time lapse SEM photographs of healthy versus infected seeds revealed that hyphae under water stress conditions grew toward and culminated their attack at the abscission layer of the floret attachment scar. A prominent infection cushion, apparent macroscopically as a white tuft of mycelium at the radicle end of the seed, developed within 48 h after inoculation. Seeds that lacked an infection cushion completed germination upon transfer to free water, whereas seeds with an infection cushion were almost always killed. In addition, hyphae on seeds that did not initiate germination lacked directional growth and did not develop the infection cushion. This strongly suggests that the fungal attack is triggered by seed exudates released through the floret attachment scar at the initiation of germination. Images of cross sections of infected seeds showed that the fungal hyphae first penetrated the caryposis wall, then entered the embryo, and later ramified throughout the endosperm, completely destroying the seed. PMID:25389704

Franke, JanaLynn; Geary, Brad; Meyer, Susan E

2014-12-01

429

Seasonal Variation in Seed Dispersal by Tamarins Alters Seed Rain in a Secondary Rain Forest  

PubMed Central

Reduced dispersal of large seeds into degraded areas is one of the major factors limiting rain forest regeneration, as many seed dispersers capable of transporting large seeds avoid these sites with a limited forest cover. However, the small size of tamarins allows them to use small trees, and hence to disperse seeds into young secondary forests. Seasonal variations in diet and home range use might modify their contribution to forest regeneration through an impact on the seed rain. For a 2-yr period, we followed a mixed-species group of tamarins in Peru to determine how their role as seed dispersers in a 9-yr-old secondary-growth forest varied across seasons. These tamarins dispersed small to large seeds of 166 tree species, 63 of which were into a degraded area. Tamarins’ efficiency in dispersing seeds from primary to secondary forest varied across seasons. During the late wet season, high dietary diversity and long forays in secondary forest allowed them to disperse large seeds involved in later stages of regeneration. This occurred precisely when tamarins spent a more equal amount of time eating a high diversity of fruit species in primary forest and pioneer species in secondary forest. We hypothesized that well-balanced fruit availability induced the movement of seed dispersers between these 2 habitats. The noteworthy number of large-seeded plant species dispersed by such small primates suggests that tamarins play an important, but previously neglected, role in the regeneration and maintenance of forest structure. Electronic supplementary material The online version of this article (doi:10.1007/s10764-010-9413-7) contains supplementary material, which is available to authorized users. PMID:20651905

Muñoz Lazo, Fernando Julio João; Huynen, Marie-Claude; Poncin, Pascal; Heymann, Eckhard W.

2010-01-01

430

Contagious Deposition of Seeds in Spider Monkeys' Sleeping Trees Limits Effective Seed Dispersal in Fragmented Landscapes  

PubMed Central

The repeated use of sleeping sites by frugivorous vertebrates promotes the deposition and aggregation of copious amounts of seeds in these sites. This spatially contagious pattern of seed deposition has key implications for seed dispersal, particularly because such patterns can persist through recruitment. Assessing the seed rain patterns in sleeping sites thus represents a fundamental step in understanding the spatial structure and regeneration of plant assemblages. We evaluated the seed rain produced by spider monkeys (Ateles geoffroyi) in latrines located beneath 60 sleeping trees in two continuous forest sites (CFS) and three forest fragments (FF) in the Lacandona rainforest, Mexico. We tested for differences among latrines, among sites, and between forest conditions in the abundance, diversity (?-, ?- and, ?-components) and evenness of seed assemblages. We recorded 45,919 seeds ?5 mm (in length) from 68 species. The abundance of seeds was 1.7 times higher in FF than in CFS, particularly because of the dominance of a few plant species. As a consequence, community evenness tended to be lower within FF. ?-diversity of common and dominant species was two times greater among FF than between CFS. Although mean ?-diversity per latrine did not differ among sites, the greater ?-diversity among latrines in CFS increased ?-diversity in these sites, particularly when considering common and dominant species. Our results support the hypothesis that fruit scarcity in FF can ‘force’ spider monkeys to deplete the available fruit patches more intensively than in CFS. This feeding strategy can limit the effectiveness of spider monkeys as seed dispersers in FF, because (i) it can limit the number of seed dispersers visiting such fruit patches; (ii) it increases seed dispersal limitation; and (iii) it can contribute to the floristic homogenization (i.e., reduced ?-diversity among latrines) in fragmented landscapes. PMID:24586705

González-Zamora, Arturo; Arroyo-Rodríguez, Víctor; Escobar, Federico; Rös, Matthias; Oyama, Ken; Ibarra-Manríquez, Guillermo; Stoner, Kathryn E.; Chapman, Colin A.

2014-01-01

431

Comparison Between High and Low Source Activity Seeds for I-125 Permanent Seed Prostate Brachytherapy  

SciTech Connect

Purpose: To compare low (mean 0.44, SD {+-} 0.0163 mCi) with high source activity (0.61 {+-} 0.0178 mCi) in I{sup 125} permanent seed brachytherapy regarding seed loss, dosimetric outcome, and toxicity. Methods and Materials: The study included 199 patients with prostate cancer treated by permanent seed brachytherapy alone: the first 105 with seeds of lower activity (first cohort), the following 94 with higher seed activity (second cohort). The V100, V150, V200, and D90 were analyzed on the CT scan 30 days after implantation (CTD30). The V100, V150, and D2 of the rectum were also calculated on CTD30. Seed loss was determined 30 days after implantation. Urinary toxicity was measured with the International Prostate Symptom Score (IPSS) questionnaire. Results: Lower seed activity was associated with lower V150 and V200 (p = 0.01 and p {<=} 0.001, respectively) on CTD30. More patients had a V100 <90% and D90 <140 Gy in the lower activity cohort (p = 0.098 for D90 and p = 0.029 for V100) on CTD30. There was no difference between cohorts in dose to the rectum (p = 0.325-0.516) or difference in patients' IPSS score from baseline (p = 0.0.117-0.618), although there was a trend toward more urinary toxicity at 4 and 8 months for high activity seeds. Seed loss as a percentage of implanted seeds was not different (p = 0.324). Conclusions: Higher seed activity (I{sup 125} {>=} 0.6 mCi) results in at least equal V100 and D90 on CTD30. However, dose inhomogeneity and a trend toward more urinary toxicity at 4 and 8 months after treatment may lead to a higher long-term urinary complications.

Masucci, Giuseppina Laura; Donath, David; Tetreault-Laflamme, Audrey; Carrier, Jean-Francois; Hervieux, Yannick; Larouche, Renee Xaviere; Bahary, Jean-Paul [Department of Radiation Oncology Centre Hospitalier de l'Universite de Montreal, Montreal (Canada); Taussky, Daniel, E-mail: daniel.taussky.chum@ssss.gouv.qc.c [Department of Radiation Oncology Centre Hospitalier de l'Universite de Montreal, Montreal (Canada)

2010-11-01

432

Uncoupling the Effects of Seed Predation and Seed Dispersal by Granivorous Ants on Plant Population Dynamics  

PubMed Central

Secondary seed dispersal is an important plant-animal interaction, which is central to understanding plant population and community dynamics. Very little information is still available on the effects of dispersal on plant demography and, particularly, for ant-seed dispersal interactions. As many other interactions, seed dispersal by animals involves costs (seed predation) and benefits (seed dispersal), the balance of which determines the outcome of the interaction. Separate quantification of each of them is essential in order to understand the effects of this interaction. To address this issue, we have successfully separated and analyzed the costs and benefits of seed dispersal by seed-harvesting ants on the plant population dynamics of three shrub species with different traits. To that aim a stochastic, spatially-explicit individually-based simulation model has been implemented based on actual data sets. The results from our simulation model agree with theoretical models of plant response dependent on seed dispersal, for one plant species, and ant-mediated seed predation, for another one. In these cases, model predictions were close to the observed values at field. Nonetheless, these ecological processes did not affect in anyway a third species, for which the model predictions were far from the observed values. This indicates that the balance between costs and benefits associated to secondary seed dispersal is clearly related to specific traits. This study is one of the first works that analyze tradeoffs of secondary seed dispersal on plant population dynamics, by disentangling the effects of related costs and benefits. We suggest analyzing the effects of interactions on population dynamics as opposed to merely analyzing the partners and their interaction strength. PMID:22880125

Arnan, Xavier; Molowny-Horas, Roberto; Rodrigo, Anselm; Retana, Javier

2012-01-01

433

Frequency conversion system  

NASA Technical Reports Server (NTRS)

A frequency conversion system comprises first and second gain sources providing first and second frequency radiation outputs where the second gain source receives as input the output of the first gain source and, further, the second gain source comprises a Raman or Brillouin gain fiber for wave shifting a portion of the radiation of the first frequency output into second frequency radiation output to provided a combined output of first and second frequencies. Powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Raman/Brillouin amplifier or oscillator between the high power source and the NFM device. Further, polarization conversion using Raman or Brillouin wavelength shifting is provided to optimize frequency conversion efficiency in the NFM device.

Sanders, Steven (Inventor); Waarts, Robert G. (Inventor)

2001-01-01

434

Association Studies and Legume Synteny Reveal Haplotypes Determining Seed Size in Vigna unguiculata  

PubMed Central

Highly specific seed market classes for cowpea and other grain legumes exist because grain is most commonly cooked and consumed whole. Size, shape, color, and texture are critical features of these market classes and breeders target development of cultivars for market acceptance. Resistance to biotic and abiotic stresses that are absent from elite breeding material are often introgressed through crosses to landraces or wild relatives. When crosses are made between parents with different grain quality characteristics, recovery of progeny with acceptable or enhanced grain quality is problematic. Thus genetic markers for grain quality traits can help in pyramiding genes needed for specific market classes. Allelic variation dictating the inheritance of seed size can be tagged and used to assist the selection of large seeded lines. In this work we applied 1,536-plex SNP genotyping and knowledge of legume synteny to characterize regions of the cowpea genome associated with seed size. These marker-trait associations will enable breeders to use marker-based selection approaches to increase the frequency of progeny with large seed. For 804 individuals derived from eight bi-parental populations, QTL analysis was used to identify markers linked to 10 trait determinants. In addition, the population structure of 171 samples from the USDA core collection was identified and incorporated into a genome-wide association study which supported more than half of the trait-associated regions important in the bi-parental populations. Seven of the total 10 QTLs were supported based on synteny to seed size associated regions identified in the related legume soybean. In addition to delivering markers linked to major trait determinants in the context of modern breeding, we provide an analysis of the diversity of the USDA core collection of cowpea to identify genepools, migrants, admixture, and duplicates. PMID:23596454

Lucas, Mitchell R.; Huynh, Bao-Lam; da Silva Vinholes, Patricia; Cisse, Ndiaga; Drabo, Issa; Ehlers, Jeffrey D.; Roberts, Philip A.; Close, Timothy J.

2013-01-01

435

Amplification of spontaneous emission in 2?m single frequency master oscillator and fiber power amplifier  

NASA Astrophysics Data System (ADS)

A single-frequency master-oscillator fiber power-amplifier operating at 1991 nm was demonstrated. The seeding laser was a diode-pumped, high efficient, single-longitudinal-mode Tm:YAP laser with a coupled-cavity configuration. 721 mW single-frequency output power was obtained at 1991 nm, the slope efficiency was 46%. The power amplifier was a diode-pumped Tm-doped fiber. 8.6 W single frequency output power was obtained from the amplifier. The maximum output power was limited by the low coupling efficiency of the seeding signal into the fiber core. The strength of ASE in the fiber amplifier with respect to the power of input signal was studied experimentally. High power single-frequency lasers at 2 ?m optical region have potential applications on eye-safe coherent lidar and optical remote sensing.

Li, Jing; Yang, Suhui; Zhao, Changming; Zhang, Haiyang; Xie, Wen

2010-11-01

436

Gene expression analysis of flax seed development  

PubMed Central

Background Flax, Linum usitatissimum L., is an important crop whose seed oil and stem fiber have multiple industrial applications. Flax seeds are also well-known for their nutritional attributes, viz., omega-3 fatty acids in the oil and lignans and mucilage from the seed coat. In spite of the importance of this crop, there are few molecular resources that can be utilized toward improving seed traits. Here, we describe flax embryo and seed development and generation of comprehensive genomic resources for the flax seed. Results We describe a large-scale generation and analysis of expressed sequences in various tissues. Collectively, the 13 libraries we have used provide a broad representation of genes active in developing embryos (globular, heart, torpedo, cotyledon and mature stages) seed coats (globular and torpedo stages) and endosperm (pooled globular to torpedo stages) and genes expressed in flowers, etiolated seedlings, leaves, and stem tissue. A total of 261,272 expressed sequence tags (EST) (GenBank accessions LIBEST_026995 to LIBEST_027011) were generated. These EST libraries included transcription factor genes that are typically expressed at low levels, indicating that the depth is adequate for in silico expression analysis. Assembly of the ESTs resulted in 30,640 unigenes and 82% of these could be identified on the basis of homology to known and hypothetical genes from other plants. When compared with fully sequenced plant genomes, the flax unigenes resembled poplar and castor bean more than grape, sorghum, rice or Arabidopsis. Nearly one-fifth of these (5,152) had no homologs in sequences reported for any organism, suggesting that this category represents genes that are likely unique to flax. Digital analyses revealed gene expression dynamics for the biosynthesis of a number of important seed constituents during seed development. Conclusions We have developed a foundational database of expressed sequences and collection of plasmid clones that comprise even low-expressed genes such as those encoding transcription factors. This has allowed us to delineate the spatio-temporal aspects of gene expression underlying the biosynthesis of a number of important seed constituents in flax. Flax belongs to a taxonomic group of diverse plants and the large sequence database will allow for evolutionary studies as well. PMID:21529361

2011-01-01

437

Precise wavelength control of a single-frequency pulsed Ho:Tm:YLF laser.  

PubMed

We demonstrate wavelength control of a single-frequency diode-pumped Ho:Tm:YLF laser by referencing its wavelength to an absorption line of carbon dioxide. We accomplish this wavelength control by injection seeding with a cw Ho:Tm:YLF laser that can be tuned over or stabilized to carbon dioxide or water vapor lines. We show that the pulsed laser can be scanned precisely over an absorption line of carbon dioxide by scanning the injection seed laser wavelength. We locked the pulsed laser to within 18.5 MHz of the absorption line center by stabilizing the injection seed on the line center. The single-frequency pulsed output, intended for use as a transmitter for differential absorption lidar detection of atmospheric carbon dioxide and water vapor and for coherent detection of wind, is 100 mJ per pulse at a 5-Hz repetition rate. PMID:11921801

Koch, Grady J; Petros, Mulugeta; Yu, Jirong; Singh, Upendra N

2002-03-20

438

A prospective study on pain score with transperineal prostatic gold seed fiducial implantation under local anesthetic alone  

PubMed Central

Background: The purpose of this study was to monitor patient pain score with transperineal prostatic gold seed implantation in the absence of conscious sedation. Methods: All patients who were scheduled for image-guided external beam radiation (IGRT) and referred for gold seed fiducials were eligible to participate. Gold seed implants were performed by two radiation oncologists between December 2007 and April 2008. Patients received only local and deep anesthetic. No patients had prophylactic IV cannulation for the procedure. Three gold seeds were inserted transperineally into the prostate. A visual analogue scale from 0 to 10 was used to assess the pain at baseline, local and deep anesthetic infiltration, with each seed drop, and after the completion of the procedure. Results: A total of 30 patients were accrued to this study. The highest recorded increase in pain score was at the time point of deep local anesthesia, at which the mean pain score was 3.8. The mean pain scores at each seed drop were 0.8 (standard deviation [SD]=1.24), 1 (SD=1.26), and 0.5 (SD=0.90), respectively. All gold seed insertion procedures were well-tolerated, with no patients having significant pain post-procedure, and no significant procedural complications. There were only slight increases in dysuria, urinary frequency, constipation, urinary retention and flatulence in 7 patients – none of which required intervention. Interpretation: Transperineal ultrasound-guided gold seed implantation without conscious sedation is well-tolerated and associated with a low complication rate. It is a convenient outpatient procedure obviating the need for resource intensive postoperative monitoring. PMID:23671528

Tang, Colin. I.; Sethukavalan, Perakaa; Cheung, Patrick; Morton, Gerard; Pang, Geordi; Loblaw, D. Andrew

2013-01-01

439

Long-term effects of seeding after wildfire on vegetation in Great Basin shrubland ecosystems  

E-print Network

. Seeding native shrubs, particularly Artemisia tridentata, did not increase shrub cover or density seeding, Artemisia tridentata, Bromus, cheatgrass, drill seeding, exotic annuals, non-native annuals

440

Genetic Analysis of Seed-Soluble Oligosaccharides in Relation to Seed Storability of Arabidopsis1  

PubMed Central

Seed oligosaccharides (OSs) and especially raffinose series OSs (RSOs) are hypothesized to play an important role in the acquisition of desiccation tolerance and consequently in seed storability. In the present work we analyzed the seed-soluble OS (sucrose, raffinose, and stachyose) content of several Arabidopsis accessions and thus identified the genotype Cape Verde Islands having a very low RSO content. By performing quantitative trait loci (QTL) mapping in a recombinant inbred line population, we found one major QTL responsible for the practically monogenic segregation of seed stachyose content. This locus also affected the content of the two other OSs, sucrose, and raffinose. Two candidate genes encoding respectively for galactinol synthase and raffinose synthase were located within the genomic region around this major QTL. In addition, three smaller-effect QTL were identified, each one specifically affecting the content of an individual OS. Seed storability was analyzed in the same recombinant inbred line population by measuring viability (germination) under two different seed aging assays: after natural aging during 4 years of dry storage at room temperature and after artificial aging induced by a controlled deterioration test. Thus, four QTL responsible for the variation of this trait were mapped. Comparison of the QTL genetic positions showed that the genomic region containing the major OS locus did not significantly affect the seed storability. We concluded that in the studied material neither RSOs nor sucrose content had a specific effect on seed storability. PMID:11115877

Bentsink, Leónie; Alonso-Blanco, Carlos; Vreugdenhil, Dick; Tesnier, Karine; Groot, Steven P.C.; Koornneef, Maarten

2000-01-01

441

TIMING OF SEED DISPERSAL GENERATES A BIMODAL SEED BANK DEPTH DISTRIBUTION1  

Microsoft Academic Search

The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that develop deep soil cracks during the dry season, it is

Ken Thompson; LUIS V. G ARCIA

2005-01-01

442

Hydrothermal time analysis of seed dormancy in true (botanical) potato seeds  

E-print Network

to water potential (C) and temperature (T) can describe these features of seed behaviour. We used) of TPS for 7 or 30 days partially or fully alleviated primary dormancy. The median base water potential model, temperature, water potential Introduction Dormancy is the lack of the capacity for a seed `to

Bradford, Kent

443

Seed Coat Microsculpturing Changes during Seed Development in Diploid and Amphidiploid Brassica Species  

PubMed Central

• Background and Aims Seed coat morphology is known to be an excellent character for taxonomic and evolutionary studies, thus understanding its structure and development has been an important goal for biologists. This research aimed to identify the developmental differences of seed coats between amphidiploids and their putative parents in Brassica. • Methods Scanning electron microscope (SEM) studies were carried out on six species (12 accessions), three amphidiploids and their three diploid parents. • Key Results Twelve types of basic ornamentation patterns were recognized during the whole developmental process of the seed coat. Six types of seed coat patterns appeared in three accessions of Brassica rapa, five types in B. oleracea, B. nigra and B. carinata, seven types in B. napus, and eight types in B. juncea. There was less difference among seed coat patterns of the three accessions of B. rapa. The reticulate and blister types were two of the most common patterns during the development of seeds in the six species, the blister?pimple and the pimple?foveate patterns were characteristic of B. rapa, and the ruminate of B. oleracea and B. nigra. The development of seed coat pattern in amphidiploids varied complicatedly. Some accessions showed intermediate patterns between the two putative parents, while others resembled only one of the two parents. • Conclusions The variation in the patterns of seed coat development could be used to provide a new and more effective way to analyse the close relationship among amphidiploids and their ancestral parents. PMID:15037452

ZENG, CHANG?LI; WANG, JIAN?BO; LIU, AI?HUA; WU, XIAO?MING

2004-01-01

444

Drift Seeds And Drift Fruits : Seeds That Ride The Ocean Currents  

NSDL National Science Digital Library

This essay explores seed dispersal by water and describes some of the physical adaptations that evolution has produced in the seeds and fruits that travel this way. There is a background essay, discussion questions, state and national standards, and links to related Teacher's Domain resources.

2007-01-01

445

Seed predation and selection exerted by a seed predator influence subalpine tree densities.  

PubMed

Strongly interacting species often have pronounced direct and indirect effects on other species. Here we focus of the effects of pine squirrels (Tamiasciurus spp.), which are a dominant pre-dispersal seed predator of many conifers including limber pines (Pinus flexilis) and whitebark pines (P. albicaulis). Pine squirrels depress seed abundance by harvesting most limber and whitebark pine cones on their territories. Pine squirrels further reduce seed availability for Clark's Nutcrackers (Nucifraga columbiana), the primary seed disperser of these pines, because selection exerted by pine squirrels has reduced the number of seeds per cone and causes seeds to be less accessible. We predicted that, if fewer seeds were available for dispersal by nutcrackers, pine recruitment should be suppressed in areas with pine squirrels. In support of this prediction, stand densities were about two times greater in areas where pine squirrels are absent than in areas where they are present. Alternative explanations that we considered do not account for these differences; however, precipitation may limit stand densities in the absence of seed limitation by pine squirrels. In sum, pine squirrels apparently depress limber and whitebark pine stand densities, with the potential for ecosystem impacts because these pines are foundation species within Western subalpine ecosystems. PMID:18959333

Siepielski, Adam M; Benkman, Craig W

2008-10-01

446

Soybean seed phenol, lignin, and isoflavones partitioning as affected by seed node position and genotype differences  

Technology Transfer Automated Retrieval System (TEKTRAN)

Factors controlling the production and partitioning of seed phenolics within soybean are not understood. Understanding these factors may justify selection for higher levels of seed phenolics because of their beneficial impact on human health and soybean defense against diseases. The objective of thi...

447

Seed dispersal is more limiting to native grassland diversity than competition or seed predation  

E-print Network

on plant community diversity. This assumption, however, is sel- dom tested. As well, there are a variety-words: determinants of plant community diversity and structure, dispersal limitation, dominance, relative abundanceSeed dispersal is more limiting to native grassland diversity than competition or seed predation

448

Seed dispersal by water: a contribution to the interpretation of seed assemblages  

Microsoft Academic Search

The composition of a seed flora always differs from actual vegetation. For archaeobotanists, who try to reconstruct former communities on the basis of plant macrofossils extracted from soil samples, this is a serious handicap. This difference can be explained by dispersal processes and by differences in preservation. Seeds that are incorporated into the soil may originate from both local and

R. T. J. Cappers

1993-01-01

449

EFFECTS OF HARVESTING AND SEED-COTTON CLEANING ON A COTTON WITH A FRAGILE SEED COAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seed coat fragments that remain in lint after the ginning process decrease spinning efficiency at the textile mill, and ultimately reduce the quality of finished goods. An experiment was conducted to determine the interactions between harvest and seed-cotton cleaning treatments using an upland cult...

450

Improving the sludge conditioning potential of moringa seed  

NASA Astrophysics Data System (ADS)

In the search for a cheaper material to effectively condition sludge, oil-free moringa seed was prepared and tested. A Soxhlet apparatus was used to extract the oil from moringa seed ( Moringa oleifera). The oil-free seed (marc) has been found to have higher conditioning potential than the ordinary moringa seed. However, the traditional ferric chloride is still a better sludge conditioner than moringa seed marc. For the digested domestic sludge used, optimum conditioning dosages were found to be 0.6, 0.80, and 1.10% of the total solids for ferric chloride, marc of the moringa seed, and ordinary moringa seed, respectively. Since little or no operational material is lost in the extraction process, the moringa seed marc is a promising conditioner in place of the ordinary seed.

Ademiluyi, Joel O.; Eze, Romanus M.

1990-01-01

451

Big sagebrush seed storage. Forest Service research note  

SciTech Connect

Big sagebrush (Artemisia tridentata Nutt.) seeds were stored in three different environments; cool, constant temperature (refrigerator 10 degs. C); room temperature (14 to 24 degs. C); and a nonheated warehouse (-28 to +44 degs. C). In all three cases, humidity was held constant and equal. Significant drop in seed viability occurred first in the seed stored in the nonheated warehouse, followed by seed stored at room temperatures, and then seed stored at cool temperatures. It appeared from this study and studies by others that humidity control is more important to maintaining seed viability than temperature control. The old adage simply states `store seeds in a cool and dry place` - but first make sure the seeds have been properly dried. Drying sagebrush seed during the cool, wet weather of the harvesting period creates special challenges to the producer.

Welch, B.L.; Briggs, S.F.; Johansen, J.H.

1996-12-01

452

Frugivory and seed dispersal by hornbills (Bucerotidae) in tropical forests  

NASA Astrophysics Data System (ADS)

I summarize the current knowledge of frugivory and seed dispersal by hornbills in tropical forests. Many studies report on frugivory by hornbills but few specifically identify hornbills as effective dispersers. Hornbills are able to disperse a diverse array of fruits in tropical forests (748 plant species from 252 genera and 79 families) and move many of the seeds far from the parent trees. They digest only the fleshy parts of fruits that they swallow and then regurgitate/defecate the seeds intact. The relatively long seed retention times (>1 h) and propensity for depositing seeds away from the parent trees while foraging suggest high-quality dispersal. Some seeds might be aggregated at nest and roost sites, but hornbills are capable of dispersing seeds over several kilometers, resulting in a relatively even spread of seeds throughout the forest. Based on the results summarized here, hornbills provide excellent seed dispersal services to tropical plants in their respective habitats.

Kitamura, Shumpei

2011-11-01

453

Natural Variation for Seed Longevity and Seed Dormancy Are Negatively Correlated in Arabidopsis1[W][OA  

PubMed Central

Dormancy is a state of metabolic arrest that facilitates the survival of organisms during environmental conditions incompatible with their regular course of life. Many organisms have deep dormant stages to promote an extended life span (increased longevity). In contrast, plants have seed dormancy and seed longevity described as two traits. Seed dormancy is defined as a temporary failure of a viable seed to germinate in conditions that favor germination, whereas seed longevity is defined as seed viability after dry storage (storability). In plants, the association of seed longevity with seed dormancy has not been studied in detail. This is surprising given the ecological, agronomical, and economic importance of seed longevity. We studied seed longevity to reveal its genetic regulators and its association with seed dormancy in Arabidopsis (Arabidopsis thaliana). Integrated quantitative trait locus analyses for seed longevity, in six recombinant inbred line populations, revealed five loci: Germination Ability After Storage1 (GAAS1) to GAAS5. GAAS loci colocated with seed dormancy loci, Delay Of Germination (DOG), earlier identified in the same six recombinant inbred line populations. Both GAAS loci and their colocation with DOG loci were validated by near isogenic lines. A negative correlation was observed, deep seed dormancy correlating with low seed longevity and vice versa. Detailed analysis on the collocating GAAS5 and DOG1 quantitative trait loci revealed that the DOG1-Cape Verde Islands allele both reduces seed longevity and increases seed dormancy. To our knowledge, this study is the first to report a negative correlation between seed longevity and seed dormancy. PMID:23085841

Nguyen, Thu-Phuong; Keizer, Paul; van Eeuwijk, Fred; Smeekens, Sjef; Bentsink, Leónie

2012-01-01

454

Seed Development in Phaseolus vulgaris L. cv Seminole  

PubMed Central

Phaseolus vulgaris L. cv Seminole pods removed from the plant continued their development when incubated in suitable conditions. Seeds continued to grow and develop and pods and seeds passed through an apparently normal developmental sequence to dryness. Seed growth was at the expense of pod dry weight (DW) reserves. Losses of pod DW paralleled DW gains by seeds in detached pods and in pod cylinders containing a seed. The transfer activity was apparent only within the period 10 to 30 days after anthesis (DAA) with maximal activity between 15 to 20 DAA. This period corresponds to maximum pod growth and the attainment of maximal DW. Seeds are in only the early phase of seed growth at this time. No DW transfer was observed at developmental stages beyond 30 to 35 DAA when normal senescence DW losses in pods became evident and seeds were in the later phase of seed fill. Pods or pod cylinders remained green and succulent over the transfer period, later passing through yellowing and drying phases characteristic of normal development. DW transfer was dependent on funicle integrity and was readily detectable in pod cylinders after 7 days incubation. The DW transfer activity may contribute to continuing nutrition of seeds under conditions where the normal assimilate supply to seeds becomes limiting. Defoliation and water stress treatments applied to Phaseolus plants reduced seed yields but allowed persistence of seed maturation processes such that all seeds developing to dryness were capable of germination. PMID:16666535

Fountain, David W.; Outred, Heather A.; Holdsworth, Jacqueline M.; Thomas, Roderick G.

1989-01-01

455

Viability Prediction of Ricinus cummunis L. Seeds Using Multispectral Imaging.  

PubMed

The purpose of this study was to highlight the use of multispectral imaging in seed quality testing of castor seeds. Visually, 120 seeds were divided into three classes: yellow, grey and black seeds. Thereafter, images at 19 different wavelengths ranging from 375-970 nm were captured of all the seeds. Mean intensity for each single seed was extracted from the images, and a significant difference between the three colour classes was observed, with the best separation in the near-infrared wavelengths. A specified feature (RegionMSI mean) based on normalized canonical discriminant analysis, were employed and viable seeds were distinguished from dead seeds with 92% accuracy. The same model was tested on a validation set of seeds. These seeds were divided into two groups depending on germination ability, 241 were predicted as viable and expected to germinate and 59 were predicted as dead or non-germinated seeds. This validation of the model resulted in 96% correct classification of the seeds. The results illustrate how multispectral imaging technology can be employed for prediction of viable castor seeds, based on seed coat colour. PMID:25690554

Olesen, Merete Halkjær; Nikneshan, Pejman; Shrestha, Santosh; Tadayyon, Ali; Deleuran, Lise Christina; Boelt, Birte; Gislum, René

2015-01-01

456

Seed dormancy distribution: explanatory ecological factors  

PubMed Central

Background and Aims Knowledge of those traits that vary with latitude should be helpful in predicting how they may evolve locally under climate change. In the sea beet Beta vulgaris ssp. maritima, seed dormancy largely controls the timing of germination, is highly heritable and varies geographically; it is therefore thought to be selected by climate. The aim here was to characterize the variation in seed dormancy among sea beet populations across the French distribution area, as well as the ecological factors in situ that are correlated with and that could therefore select for seed dormancy. The relative importance of genetic inheritance vs. non-genetic variation is also evaluated. Methods The proportions of dormant seeds from 85 natural populations encompassing different climates over the whole French distribution area were measured under controlled conditions. Germination phenology was observed in a common garden experiment. Dormancy variation of seeds collected in situ was compared with that of seeds collected on plants grown in the greenhouse. Key Results The proportions of dormant seeds in the greenhouse were highly variable, covering almost the entire range from 0 to 1, and followed a geographical pattern from lower dormancy at high latitudes to high dormancy at low latitudes. The distribution of dormancy was positively correlated with yearly temperatures, especially summer temperatures. Minimum temperatures in winter did not significantly explain the trait variation. The genetic component of the total variation was significant and is probably completed by an important adjustment to the local conditions brought about by maternal adaptive phenotypic plasticity. Conclusions Dormancy in sea beet could be interpreted as a way to limit summer germination and spread germination over the first autumn and spring or following autumns. This highly heritable trait has the potential to evolve in the relatively near future because of climate change. PMID:22952378

Wagmann, Kristen; Hautekèete, Nina-Coralie; Piquot, Yves; Meunier, Cécile; Schmitt, S. Eric; Van Dijk, Henk

2012-01-01

457

Survey of the mycoflora and mycotoxins of cotton seeds and cotton seed products in Egypt.  

PubMed

Thirty-nine species and 16 fungal genera were isolated from Egyptian cotton seeds, cotton seed meal and cotton seed cake on 1% glucose-Czapek's agar medium incubated at 28 degrees C. Aspergillus was the most frequent genus and it emerged in 87-100% of the samples contributing 70-98% of total fungi in the three substrates tested. The most common species were A. niger, A. flavus, A. fumigatus, A. terreus and Rhizopus stolonifer; A. niger, A. fumigatus and Penicillium corylophilum; and A. niger, A. flavus, A. terreus, A. nidulans and Rhizopus stolonifer, respectively. Cotton seeds and cotton seed products were naturally contaminated by aflatoxin B1 and B2. About 16% of the different substrates tested were positive for aflatoxin contamination. No citrinin, ochratoxin A, patulin, sterigmatocystin, diacetoxyscirpenol, T-2 toxin or zearalenone were detected in the samples assayed. PMID:2388680

Mazen, M B; el-Kady, I A; Saber, S M

1990-06-01

458

Industrial-scale radio frequency treatments for insect control in lentils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Radio frequency (RF) treatments are considered to be a potential postharvest technology for disinfesting legumes of internal seed pests such as the cowpea weevil. After treatment protocols are shown to control postharvest insects without significant quality degradation, it is important to scale-up l...

459

High-frequency plant regeneration through cyclic secondary somatic embryogenesis in black pepper ( Piper nigrum L.)  

Microsoft Academic Search

A high-frequency plantlet regeneration protocol was developed for black pepper (Piper nigrum L.) through cyclic secondary somatic embryogenesis. Secondary embryos formed from the radicular end of the primary somatic embryos which were originally derived from micropylar tissues of germinating seeds on growth regulator-free SH medium in the absence of light. The process of secondary embryogenesis continued in a cyclic manner

R. Ramakrishnan Nair; S. Dutta Gupta

2006-01-01

460

Study of the length dependence of frequency-doubled light in optical fibers  

Microsoft Academic Search

It is found that the length dependence for frequency-doubled light in optical fibers is directly related to the amount of green seed used during the preparation stage. These measurements also show that self-phase modulation is not responsible for the saturation of the SHG signal with length. From these measurements it is also seen that the SH light is subject to

B. Batdorf; C. Krautschik; U. Österberg; G. Stegeman; J. W. Leitch; J. R. Rotgé; T. F. Morse

1989-01-01

461

Stabilized radio frequency quadrupole  

DOEpatents

Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1984-12-25

462

Ultrastable automatic frequency control  

NASA Technical Reports Server (NTRS)

Center frequency of wideband AFC circuit drifts only hundredths of percent per day. Since circuit responds only to slow frequency drifts and modulation signal has high-pass characteristics, AFC does not interfere with normal FM operation. Stable oscillator, reset circuit, and pulse generator constitute time-averaging discriminator; digital counter in pulse generator replaces usual monostable multivibrator.

Sabourin, D. J.; Furiga, A.

1981-01-01

463

FREQUENCY ASSIGNMENT PROBLEMS  

Microsoft Academic Search

The ever growing number of wireless communications systems deployed around the globe have made the optimal assignment of a limited radio frequency spectrum a problem of primary importance. At issue are planning models for permanent spectrum al- location, licensing, regulation, and network design. Furt her at issue are on-line algorithms for dynamically assigning frequencies to users within an es tablished

ROBERT A. MURPHEY; PANOS M. PARDALOS; MAURICIO G. C. RESE

464

Wavelet frequency decomposition method  

NASA Astrophysics Data System (ADS)

A wavelet variation of the frequency decomposition multigrid method of Hackbusch is presented. The perfect reconstruction property of the wavelet system enable us to perform the convergence analysis of the frequency decomposition method. Some applications of this method are also presented.

Rieder, Andreas; Wells, Raymond O., Jr.; Zhou, Xiaodong

1994-03-01

465

Optical frequency metrology  

Microsoft Academic Search

Extremely narrow optical resonances in cold atoms or single trapped ions can be measured with high resolution. A laser locked to such a narrow optical resonance could serve as a highly stable oscillator for an all-optical atomic clock. However, until recently there was no reliable clockwork mechanism that could count optical frequencies of hundreds of terahertz. Techniques using femtosecond-laser frequency

Th. Udem; R. Holzwarth; T. W. Hänsch

2002-01-01

466

Stabilized radio frequency quadrupole  

DOEpatents

A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

Lancaster, Henry D. (Orinda, CA); Fugitt, Jock A. (Berkeley, CA); Howard, Donald R. (Danville, CA)

1984-01-01

467

Frequency Distributions August 2009  

E-print Network

=Level of Academic Challenge ACL=Active and Collaborative Learning Interpreting the Frequency Distributions Report The Frequency Distributions report is based on information from all randomly selected students for both your the count numbers. For more information about weighting, please visit the NSSE Web site at www

468

Determining 'threshold' levels for seed-borne virus infection in seed stocks.  

PubMed

There have been many advances in testing procedures to detect seed-borne virus infection in seed samples. However, scant attention has been given to the implications of improved test results in terms of the economic losses resulting from sowing seed stocks with different amounts of infection. For agricultural and horticultural industries to use the results of tests on representative samples, defined 'threshold' values for percentage seed infection are required that identify acceptable levels of risk of economic losses resulting from sowing the virus-infected seed stocks. Such information is provided by field experiments in which infected seed is sown and the consequences are followed in terms of virus spread, yield losses and infection of newly produced seed. These field experiments need to continue over several years at diverse sites so that they represent a wide range of infection scenarios. Extensive surveys to determine seed-borne virus occurrence in different regions are also required to define areas of greater or lesser risk of economic losses. In this paper, an example is described of how field experiments and surveys were used to define 'threshold' values of seed-borne Cucumber mosaic virus infection in an annual crop (lupin: Lupinus angustifolius) and two such examples are given for pasture species: Cucumber mosaic virus in subterranean clover (Trifolium subterraneum), and Alfalfa mosaic virus in annual burr medic (Medicago polymorpha). The aim of this paper is to encourage others to address the urgent need for similar 'threshold' information with other economically important combinations of seed-borne viruses and host plant. PMID:11137171

Jones, R A

2000-11-01

469

Rapid and High Seed Germination and Large Soil Seed Bank of Senecio aquaticus in Managed Grassland  

PubMed Central

Senecio aquaticus, regionally a Red List species in Europe, has become increasingly abundant in agricultural grassland of medium to high management intensity in Switzerland, Southern Germany, and Austria in recent years, where it is a threat for animal and human health due to its toxicity. In this study, we investigated the seed ecology of S. aquaticus to help protection of the species in relic populations while improving its control when abundant in managed grassland. Germination percentages of fresh ripe seeds of S. aquaticus were on average 68% in 2008, but only 45% in 2010, indicating yearly variation. Germination was generally fast: ten days after the onset of the tests, often more than 45% of all seeds had germinated. When covered with a soil layer of 5?mm, germination was only 16% compared to 63% in full light. Seeds buried in the soil for one and two years showed a germination of 78%, significantly higher than that of fresh ripe seeds, thus suggesting a stimulating effect of cold-wet stratification on germination and long seed survival in the soil. In grasslands with established populations of S. aquaticus, the number of germinable seeds of the species ranged from 361 to 1875?m?2 in topsoil (0–10?cm) with an average of 1139?m?2. The large seed bank and the rapid and high germination of S. aquaticus suggest that allowing seed formation is important for its preservation in relic populations. With respect to agricultural grassland, strategies to control the species should initially target hindering seed production and dispersal. PMID:22272180

Suter, Matthias; Lüscher, Andreas

2012-01-01

470

Genetic control of the seed coat colour of Middle American and Andean bean seeds.  

PubMed

Seed coat colour of bean seeds is decisive for acceptance of a cultivar. The objectives of this research were to determine whether there is maternal effect for "L", a* and b* colour parameters in Middle American and Andean bean seeds; to obtain estimates of heritability and gain with selection for "L", a* and b* values; and select recombinants with the seed coat colour required by the market demand. Thus, controlled crossings were carried out between the Middle American lines CNFP 10104 and CHC 01-175, and between the Andean lines Cal 96 and Hooter, for obtaining F1, F1 reciprocal, F2 and F2 reciprocal generations for each hybrid combination. Parents and generations were evaluated in two field experiments (2012 normal rainy and 2013 dry seasons) in the state of Rio Grande do Sul, Brazil. Seed coat colour was quantified with a portable colorimeter. Genetic variability for "L" (luminosity), chromaticity a* (green to red shade), and chromaticity b* (blue to yellow shade) values was observed in seeds with F2 seed coat of Middle American and Andean beans. "L", a* and b* values in bean seeds presented maternal effects. High broad-sense heritability are observed for luminosity (h(2)b: 76.66-95.07 %), chromaticity a* (h(2)b: 73.08-89.31 %), and chromaticity b* (h(2)b: 88.63-92.50 %) values in bean seeds. From the crossings, it was possible to select bean seeds in early generation for the black group, and for carioca and cranberry types (dark or clear background) which present the colour required by the market demand. PMID:25523544

Possobom, Micheli Thaise Della Flora; Ribeiro, Nerinéia Dalfollo; Zemolin, Allan Emanoel Mezzomo; Arns, Fernanda Daltrozo

2015-02-01

471

Microfabricated ion frequency standard  

DOEpatents

A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

Schwindt, Peter (Albuquerque, NM); Biedermann, Grant (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Stick, Daniel L. (Albuquerque, NM); Serkland, Darwin K. (Albuquerque, NM); Olsson, III, Roy H. (Albuquerque, NM)

2010-12-28

472

Precision frequency synthesizing sources with excellent time/frequency performances  

NASA Technical Reports Server (NTRS)

Precision frequency synthesizing sources are needed in the time / frequency measuring system, atomic frequency standards, telemetry, communication, and radar systems. This kind of frequency synthesizing source possesses high frequency accuracy and excellent long term and short term frequency stability. Several precision frequency synthesizing sources developed by Beijing Institute of Radio Metrology and Measurement (BIRMM) which have been successfully applied to the time / frequency measuring system, atomic frequency standards system, and radar system are described. In addition, the working principle, implementation approach, and the main technical specifications of the frequency synthesizing sources are also given.

Zhou, Liren; Lin, Hai

1994-01-01

473

The Induction of Seed Germination in Arabidopsis thaliana Is Regulated Principally by Phytochrome B and Secondarily by Phytochrome A.  

PubMed Central

We examined whether spectrally active phytochrome A (PhyA) and phytochrome B (PhyB) play specific roles in the induction of seed germination in Arabidopsis thaliana (L.) Heynh., using PhyA- and PhyB-null mutants, fre1-1 (A. Nagatani, J.W. Reed, J. Chory [1993] Plant Physiol 102: 269-277) and hy3-Bo64 (J. Reed, P.Nagpal, D.S. Poole, M. Furuya, J. Chory [1993] Plant Cell 5: 147-157). When dormant seeds of each genotype imbibed in the dark on aqueous agar plates, the hy3 (phyB) mutant did not germinate, whereas the fre1 (phyA) mutant germinated at a rate of 50 to 60%, and the wild type (WT) germinated at a rate of 60 to 70%. By contrast, seeds of all genotypes germinated to nearly 100% when plated in continuous irradiation with white or red light. When plated in continuous far-red light, however, frequencies of seed germination of the WT and the fre1 and hy3 mutants averaged 14, nearly 0, and 47%, respectively, suggesting that PhyB in the red-absorbing form prevents PhyA-dependent germination under continuous far-red light. When irradiated briefly with red or far-red light after imbibition for 1 h, a typical photoreversible effect on seed germination was observed in the fre1 mutant and the WT but not in the hy3 mutant. In contrast, when allowed to imbibe in the dark for 24 to 48 h and exposed to red light, the seed germination frequencies of the hy3 mutant were more than 40%. Immunoblot analyses of the mutant seeds showed that PhyB apoprotein accumulated in dormant seeds of the WT and the fre1 mutant as much as in the seeds that had imbibed. In contrast, PhyA apoprotein, although detected in etiolated seedlings grown in the dark for 5 d, was not detectable in the dormant seeds of the WT and the hy3 mutant. The above physiological and immunochemical evidence indicates that PhyB in the far-red-absorbing form was stored in the Arabidopsis seeds and resulted in germination in the dark. Hence, PhyA does not play any role in dark germination but induces germination under continuous irradiation with far-red light. Finally, we examined seeds from a signal transduction mutant, det1, and a det1/hy3 double mutant. The det1 seeds exhibited photoreversible responses of germination on aqueous agar plates, and the det1/hy3 double mutant seeds did not. Hence, DET1 is likely to act in a distinct pathway from PhyB in the photoregulation of seed germination. PMID:12232088

Shinomura, T.; Nagatani, A.; Chory, J.; Furuya, M.

1994-01-01

474

Insights into the effects of long-term artificial selection on seed size in maize.  

PubMed

Grain produced from cereal crops is a primary source of human food and animal feed worldwide. To understand the genetic basis of seed-size variation, a grain yield component, we conducted a genome-wide scan to detect evidence of selection in the maize Krug Yellow Dent long-term divergent seed-size selection experiment. Previous studies have documented significant phenotypic divergence between the populations. Allele frequency estimates for ?3 million single nucleotide polymorphisms (SNPs) in the base population and selected populations were estimated from pooled whole-genome resequencing of 48 individuals per population. Using FST values across sliding windows, 94 divergent regions with a median of six genes per region were identified. Additionally, 2729 SNPs that reached fixation in both selected populations with opposing fixed alleles were identified, many of which clustered in two regions of the genome. Copy-number variation was highly prevalent between the selected populations, with 532 total regions identified on the basis of read-depth variation and comparative genome hybridization. Regions important for seed weight in natural variation were identified in the maize nested association mapping population. However, the number of regions that overlapped with the long-term selection experiment did not exceed that expected by chance, possibly indicating unique sources of variation between the two populations. The results of this study provide insights into the genetic elements underlying seed-size variation in maize and could also have applications for other cereal crops. PMID:25037958

Hirsch, Candice N; Flint-Garcia, Sherry A; Beissinger, Timothy M; Eichten, Steven R; Deshpande, Shweta; Barry, Kerrie; McMullen, Michael D; Holland, James B; Buckler, Edward S; Springer, Nathan; Buell, C Robin; de Leon, Natalia; Kaeppler, Shawn M

2014-09-01

475

The qSD12 Locus Controls Offspring Tissue-Imposed Seed Dormancy in Rice  

PubMed Central

Seed component structures were grouped into maternal and offspring (embryo and endosperm) tissues to characterize a dormancy quantitative trait locus (QTL) for tissue-specific function using a marker-assisted genetic approach. The approach was devised to test if genotypic/allelic frequencies of a marker tightly linked to the QTL deviate from Mendelian expectations in germinated and nongerminated subpopulations derived from a segregation population of partially after-ripened seeds and was applied to the dormancy QTL qSD12 and qSD7-1 in a nearly isogenic background of rice. Experimental results unambiguously demonstrated that qSD12 functions in the offspring tissue(s) and suggested that qSD7-1 may control dormancy through the maternal tissues. These experiments also provide the first solid evidence that an offspring tissue-imposed dormancy gene contributes to the segregation distortion in a mapping population developed from partially after-ripened seeds and, in part, to the germination heterogeneity of seeds from hybrid plants. Offspring and maternal tissue-imposed dormancy genes express in very early and late stages of the life cycle, respectively, and interact to provide the species with complementary adaptation strategies. The qSD12 locus was narrowed to the region of ?600 kbp on a high-resolution map to facilitate cloning and marker-assisted selection of the major dormancy gene. PMID:18711220

Gu, Xing-You; Turnipseed, E. Brent; Foley, Michael E.

2008-01-01

476

Imprinting in plants as a mechanism to generate seed phenotypic diversity  

PubMed Central

Normal plant development requires epigenetic regulation to enforce changes in developmental fate. Genomic imprinting is a type of epigenetic regulation in which identical alleles of genes are expressed in a parent-of-origin dependent manner. Deep sequencing of transcriptomes has identified hundreds of imprinted genes with scarce evidence for the developmental importance of individual imprinted loci. Imprinting is regulated through global DNA demethylation in the central cell prior to fertilization and directed repression of individual loci with the Polycomb Repressive Complex 2 (PRC2). There is significant evidence for transposable elements and repeat sequences near genes acting as cis-elements to determine imprinting status of a gene, implying that imprinted gene expression patterns may evolve randomly and at high frequency. Detailed genetic analysis of a few imprinted loci suggests an imprinted pattern of gene expression is often dispensable for seed development. Few genes show conserved imprinted expression within or between plant species. These data are not fully explained by current models for the evolution of imprinting in plant seeds. We suggest that imprinting may have evolved to provide a mechanism for rapid neofunctionalization of genes during seed development to increase phenotypic diversity of seeds. PMID:25674092

Bai, Fang; Settles, A. M.

2015-01-01

477

Recent results of comparative radiobiological experiments with short and long term expositions of Arabidopsis seed embryos  

NASA Astrophysics Data System (ADS)

Comparison of experimental data obtained from short (SDEF) and long duration exposure flights (LDEF) recently led to results, which will contribute for the estimation of genetic risk for long and/or repeated stay of man in space. Under orbital conditions biological stress and damage are induced in test subjects by cosmic radiation, especially the high energetic, densely ionizing component of heavy ions. Plant seeds were successful model systems for a biotest in studying the physiological damages and mutagenic effects caused by ionizing radiation in particular stem cells. In this article we present an overview of our space experiments with Arabidopis thaliana seeds. We present first results of investigations on certain damage endpoints (seed germination, plant survival, mutation frequencies), caused by cosmic ionizing radiation in dry dormant plant seeds ofArabidopsis thaliana after different short term (e.g. IML-1 and D-2) and long term (e.g. EURECA and LDEF-1) space exposures. Total dose effects of heavy ions and the other components of the mixed radiation field on damage endpoints and survival after space exposure and gamma-ray pre-irradiation were obtained. A new method of total dose spectrometry by neutron activation has been applied.

Zimmermann, M. W.; Gartenbach, K. E.; Kranz, A. R.; Baican, B.; Schopper, E.; Heilmann, C.; Reitz, G.

1996-01-01

478

Myrmecochory by small ants - Beneficial effects through elaiosome nutrition and seed dispersal  

NASA Astrophysics Data System (ADS)

Seed dispersal by ants (myrmecochory) is a common mutualism in temperate woodlands of the Northern hemisphere. In this paper we highlight the contribution of one of the most abundant ant species of Eastern Central Europe, Temnothorax crassispinus, to myrmecochory. In field and mesocosm studies we found that T. crassispinus workers disperse seeds over distances of up to 162 cm and carry them to their nests, thereby enabling the spread of Chelidonium majus seedlings. In a controlled feeding experiment with four different feeding regimes, we supplemented the respective diet of a fraction of the nests with the elaiosome-bearing seeds of C. majus and Scilla bifolia. Here, ant workers carried seeds to their nest and fed elaiosome pieces to their larvae. Subsequent production of sexual offspring and dry weights of sexual pupae were positively correlated with increasing feeding frequencies. With supplementary elaiosome feeding, the female dry weight was significantly higher, whereas the male dry weight decreased. Our results indicate a nutritional benefit from elaiosomes to the ants, which may cause shifts of investment, and at the same time underline the ecological relevance of Temnothorax ants for elaiosome-bearing plants.

Fokuhl, Gerriet; Heinze, Jürgen; Poschlod, Peter

2012-01-01

479

Crystallization of seed globulins from legumes.  

PubMed

Seeds contain large quantities of proteins and are therefore main food sources. In the last century, protein extracts of legume seeds were dialysed against distilled water and in some cases small crystals of pure protein appeared. However, those crystals were generally of poor quality with respect to X-ray diffraction. Recently, the crystallization of some of them was improved and the structures of two 7S globulins, phaseolin from Phaseolus vulgaris and canavalin from Canavalia ensiformis, have been determined at 3.0 and 2.6 A resolution, respectively. Efforts to improve the quality of the phaseolin crystals resulted in three new crystal forms which will be discussed in this paper. The only high-resolution X-ray analysis of a seed globulin from legumes is that of narbonin, a 2S protein from Vicia narbonensis. The crystal structure at 1.8 A shows a very compact packing in layers of molecules. The intermolecular contacts include salt bridges and hydrophobic clusters that might facilitate both the aggregation of the molecules and their crystallization. Because the seed globulins appear in large quantities in the protein bodies of the seeds, efficient packing of the molecules similar to the crystal packing can be assumed. PMID:15299427

Hennig, M; Schlesier, B

1994-07-01

480

Ant-mediated seed dispersal in a warmed world.  

PubMed

Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of eastern North America. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed dispersal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed. PMID:24688863

Stuble, Katharine L; Patterson, Courtney M; Rodriguez-Cabal, Mariano A; Ribbons, Relena R; Dunn, Robert R; Sanders, Nathan J

2014-01-01

481

Seeded hot dark matter models with inflation  

NASA Technical Reports Server (NTRS)

We examine massive neutrino (hot dark matter) models for large-scale structure in which the density perturbations are produced by randomly distributed relic seeds and by inflation. Power spectra, streaming velocities, and the Sachs-Wolfe quadrupole fluctuation are derived for this model. We find that the pure seeded hot dark matter model without inflation produces Sachs-Wolfe fluctuations far smaller than those seen by COBE. With the addition of inflationary perturbations, fluctuations consistent with COBE can be produced. The COBE results set the normalization of the inflationary component, which determines the large-scale (about 50/h Mpc) streaming velocities. The normalization of the seed power spectrum is a free parameter, which can be adjusted to obtain the desired fluctuations on small scales. The power spectra produced are very similar to those seen in mixed hot and cold dark matter models.

Gratsias, John; Scherrer, Robert J.; Steigman, Gary; Villumsen, Jens V.

1993-01-01

482

Antidiabetic evaluation of Mucuna pruriens, Linn seeds.  

PubMed

Effects of powdered Mucuna pruriens seeds on blood glucose levels were investigated in normal and alloxan-diabetic rabbits. In normal group 0.5, 1 and 2 g/kg of M. pruriens pulv significantly decreased the blood glucose levels while in alloxan-diabetic rabbits only 1 and 2 g/kg body weight caused a significant fall. The reference drug, acetohexamide in 500 mg/kg dose significantly reduced the blood glucose levels but in normal rabbits only. High levels of trace elements like manganese, zinc, and others were found in these seeds<