Freshly harvested sunflower (Helianthus annuus L.) seeds are considered to be dormant because they fail to germinate at relatively low temperatures (10 degrees C). This dormancy results mainly from an embryo dormancy and disappears during dry storage. Although endogenous ethylene is known to be involved in sunflower seed alleviation of dormancy, little attention had been paid to the possible ro...

Actually, the germplasm of Jatropha spp. is conserved as whole plants in field collections. Under this storage method, the genetic resources are exposed to disease, pest and natural hazards such as human error, drought and weather damage. Besides, field genebanks are costly to maintain and with important requirements of trained personnel. Thus, the development of efficient techniques to ensure ...

An embryo culture method overcomes the lengthy dormancy requirement of Taxus L. spp. (yew) seeds. When zygotic embryos excised from mature T. brevifolia L. seeds were cultured in darkness for 4 weeks on one of three basal salt media (B5, Litvay, and Murashige and Skoog), radicle emergence and seedling development was highest on B5 basal salt medium. After 1 to 2 weeks on B5 basal salt medium, s...

seed dormancy is a temporary failure of a viable seed to germinate. various methods are used for breaking seed dormancy, depending on plant species and type of dormancy. three seed populations originated from esfahan, semnan and fars provinces were exposed to different seed dormancy breaking treatments such as mechanical and chemical scarification, humid chilling, ga3 and polyethylenglycol 6000...

taxus chinensis var. mairei is a rare and endangered medicinal plant species distributed in china. in order to promote fast propagation and preserve the natural resources, conditions for in vitro germination and seedling development of embryos of t. chinensis var. mairei from anhui or zhejiang were investigated. results showed that in vitro germination rate of excised embryos cultured under 14 ...

Apple seeds (Malus domestica Borkh. cv Golden Delicious) were stratified at 5 and 15 degrees C for various lengths, weighed, and soluble protein of axis and cotyledon tissue was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Only seeds treated at 5 degrees C germinated; seeds treated at 15 degrees C did not germinate. Optimal germination required 63 days of stratificatio...

Freshly-harvested seeds of Avena sativa L. do not germinate when imbibed at temperatures higher than 25 degrees C. This high temperature dormancy is due to the seed coats, and to the low activities of glycolysis and the oxidative pentose phosphate pathway (OPP) in the embryo. The analysis by exclusion chromatography of soluble NADP(+) phosphatase activities of embryos revealed two isoforms: a 3...

The structural differences between  dormant and nondormant seeds of wild oats (Avena ludoviciana Durieu) were studied by light and transmission electron microscopy. Radial elongation of  scutellum epithelial cells were observed in nondormant seeds after imbibition, compared with dormant seeds in which cells were completely compressed. Ultrastructural differences for example, dilution of cytopla...