United States Seed Act : assistance strategy for the Czech Republic, 1993-1995 /

"Approved, July 21, 1993."

Seed farming in Britain : a practical treatise on the cultivation of vegetables for the production of seeds.

Mode of access: Internet.

De Dionysio Halicarnassensi Plutarchi qui vulgo fertur in vitis decem oratorum auctore.

Thesis (doctoral)--Leipzig.

Effect on ginning and spinning efficiency and cotton quality of fiber moisture, seed-cotton cleaning, lint cleaning /

Mode of access: Internet.

...Report on demonstration work carried out in the Western circle together with reports on the seed demonstration and cattle-breeding farms of that circle for the year...

Title varies slightly.

A contribution to the pharmacognosy of official strophanthus seed /

"Read before the British Pharmaceutical Conference in London, July, 1900."

Flora of the southeastern United States; being descriptions of the seed-plants, ferns and fern-allies growing naturally in North Carolina, South Carolin, Georgia, Florida, Tennessee, Alabama, Mississippi, Arkansas, Louisiana and the Indian territory and in Oklahoma and Texas east of the one-hundredth meridian,

Mode of access: Internet.

Gut content analysis to distinguish between seed feeding and mycophagy of a biphyllid beetle larva found on Acacia melanoxylon

In a search for potential biocontrol agents for Acacia melanoxylon R. Br. (Mimosaceae), larvae of the beetle Diplocoelus dilataticollis Lea (Coleoptera; Biphyllidae) were found within damaged seeds of A. melanoxylon. The gut contents of larvae and adults were examined to determine whether their diet included seeds, in apparent contradiction to the known mycophagous diet of members of this family of beetles. Calcofluor M2R White, a plant cell-wall staining optical brightener was used to differentiate between plant cell fragments and fungal tissue in the gut content smears. Gut contents of adults of a known seed predator of A. melanoxylon, a weevil of the genus Melanterius, were examined in the same way to provide a benchmark. The gut contents of D. dilataticollis differed from those of Melanterius sp. Fungal structures and microbes were found in the gut of D. dilataticollis, in contrast to plant cell fragments found in the gut of the weevil and from scrapes made directly from seeds. We conclude that larvae of D. dilataticollis feed primarily on fungi associated with damaged seed and therefore may not be the proximate cause of seed damage.

Storage protein mobilization and thiol protease up-regulation by solid matrix priming in loblolly pine (Pinus taeda) seed embryos

Experiments were conducted to investigate physiological mechanisms of solid matrix priming (SMP) on germination enhancement of loblolly pine (Pinus taeda) seeds. During SMP, osmotic potential in the embryo decreased by 0.65 MPa, concentration of crystalloid proteins decreased to 62% and concentrations of buffer soluble proteins and free amino acids increased by 22% and by 166%, respectively. Observations under an electron microscope demonstrated protein bodies in the embryo were mobilized. Inhibitor analysis indicated thiol protease was the dominant enzyme among endopiptidases to degrade the reserved proteins. A fragment of thiol protease was cloned from the primed seed embryos and it has high identities to those thiol proteases responsive to water stress. RNA get blot analysis showed a 1.5 kb thiol protease gene was up-regulated by SMP. Treatment with E64, a thiol protease inhibitor, negated SMP effects on germination performance, water potentials and protein profiles. Based on the experimental results, reserve protein mobilization induced by SMP in the embryo before radicle emergence might be one of the mechanisms to enhance germination in loblolly pine seeds.

Seed viability and dormancy mechanisms of Leucopogon melaleucoides Cunn. ex DC. (Epacridaceae)

Leucopogon melaleucoides, a flowering shrub, is desired by floricultural markets but is difficult to propagate. Seed viability was tested and dormancy mechanisms were studied to develop a commercial propagation system. Although around 56% of seed were viable, germination was completely inhibited unless the endocarp was removed. After-ripened seed (8 months after collection) germinated faster than fresh seed (2 days after collection), but germination occurred over a prolonged period (155 days). Germination of after-ripened seed was promoted with GA(3) or a commercial smoke product containing unknown plant growth regulators. All viable seed treated with GA(3) at 1000 mg L-1 had germinated after 24 days. The results suggest that both a physical and physiological dormancy mechanism occur for this species, with removal of the endocarp and pretreatment with 1000 mg L-1 GA(3) promoting complete germination of viable seed.

An investigation into effects of long-distance seed dispersal on organelle population genetic structure and colonization rate: a model analysis

A simulation-based modelling approach is used to examine the effects of stratified seed dispersal (representing the distribution of the majority of dispersal around the maternal parent and also rare long-distance dispersal) on the genetic structure of maternally inherited genomes and the colonization rate of expanding plant populations. The model is parameterized to approximate postglacial oak colonization in the UK, but is relevant to plant populations that exhibit stratified seed dispersal. The modelling approach considers the colonization of individual plants over a large area (three 500 km x 10 km rolled transects are used to approximate a 500 km x 300 km area). Our approach shows how the interaction of plant population dynamics with stratified dispersal can result in a spatially patchy haplotype structure. We show that while both colonization speeds and the resulting genetic structure are influenced by the characteristics of the dispersal kernel, they are robust to changes in the periodicity of long-distance events, provided the average number of long-distance dispersal events remains constant. We also consider the effects of additional physical and environmental mechanisms on plant colonization. Results show significant changes in genetic structure when the initial colonization of different haplotypes is staggered over time and when a barrier to colonization is introduced. Environmental influences on survivorship and fecundity affect both the genetic structure and the speed of colonization. The importance of these mechanisms in relation to the postglacial spread and genetic structure of oak in the UK is discussed.

Fruit processing, seed viability and dormancy mechanisms of Persoonia sericea A. Cunn. ex R. Br. and P-virgata R. Br. (Proteaceae)

The morphology of the fruit and difficulties with fruit processing impose major limitations to germination of Persoonia sericea and P. virgata. The mesocarp must be removed without harming the embryo. Fermentation of fruit or manual removal of the mesocarp was effective but digestion in 32% hydrochloric acid (HCl) completely inhibited germination. The endocarp is extremely hard and therefore very difficult and time consuming to remove without damaging the seeds. The most efficient method was cracking the endocarp with pliers, followed by manual removal of seeds. Germination was completely inhibited unless at least half of the endocarp was removed. Microbial contamination of the fruit and seeds was controlled by disinfestation and germination of the seed under aseptic conditions. The results suggest that dormancy in these species is primarily due to physical restriction of the embryo by the hard endocarp.

Segregation distortion for seed testa color in mungbean (Vigna radiata L. Wilcek)

Genetic segregation experiments with plant species are commonly used for understanding the inheritance of traits. A basic assumption in these experiments is that each gamete developed from megasporogenesis has an equal chance of fusing with a gamete developed from microsporogenesis, and every zygote formed has an equal chance of survival. If gametic and/or zygotic selection occurs whereby certain gametes or zygotic combinations have a reduced chance of survival, progeny distributions are skewed and are said to exhibit segregation distortion. In this study, inheritance data are presented for the trait seed testa color segregating in large populations (more than 200 individuals) derived from closely related mungbean (Vigna radiata L. Wilcek) taxa. Segregation ratios suggested complex inheritance, including dominant and recessive epistasis. However, this genetic model was rejected in favor of a single-gene model based on evidence of segregation distortion provided by molecular marker data. The segregation distortion occurred after each generation of self-pollination from F-1 thru F-7 resulting in F-7 phenotypic frequencies of 151:56 instead of the expected 103.5:103.5. This study highlights the value of molecular markers for understanding the inheritance of a simply inherited trait influenced by segregation distortion.

Germination response of Phalaris paradoxa L. seed to different light qualities

The influence of different light regimes on the germination of Australian and English populations of Phalaris paradoxa L. (awned canary-grass) seed was investigated to determine the impact of changing tillage practices on weed infestation. Seeds of all biotypes were highly viable, but differed in levels of innate dormancy (26-99%). In one experiment seed from a single Australian biotype, either enclosed in the spikelet glumes or having the spikelet glumes removed, were exposed to nine light treatments. Germination was stimulated by red and white light, but was inhibited by far-red light. Time to 50%, germination was less for seed enclosed in the spikelet glumes than for naked caryopses, although the final percentage of seed germinating when still enclosed in the spikelet glumes was significantly lower than for naked caryopses. In another experiment, six Australian and English biotypes with varying dormancy characteristics were exposed to eight light treatments. Red light did not stimulate germination in the deeply dormant biotype, however stimulated all other biotypes. Germination in darkness was below 20% in all biotypes except for one where germination was 51%. To overcome dormancy seeds were imbibed and placed in darkness at 16degreesC for either 7 or 14 days prior to exposure to red or white light for a single 15-min period. Dormancy in all biotypes was overcome indicating that a period of burial may decrease the dormancy level and increase seed sensitivity to light. This increased light sensitivity suggests that exposure to light during tillage may stimulate germination in P. paradoxa seed.