Dormancy in Dioscorea: Rapid Germination of Detached Embryos from Dormant Seeds of D. tokoro
- 1 March 1989
- journal article
- research article
- Published by Oxford University Press (OUP) in Plant and Cell Physiology
- Vol. 30 (2) , 287-293
- https://doi.org/10.1093/oxfordjournals.pcp.a077741
Abstract
The intact dormant seeds of Dioscorea tokoro germinate slowly if at all between 11-23°C; for full and rapid germination they require prior chilling treatment [Okagami and Kawai (1982) Bot. Mag. Tokyo 95: 155]. The germination abilities of zygotic embryos detached from dormant seeds of this species were studied under various nutritional and temperature regimes. For germination of embryos, the minimum nutritional components in Murashige and Skoog's (1962) medium that were required were sucrose and NO−3 or SO2−4. As the source of carbohydrate for germination of detached embryos, sucrose, mannose and maltose were effective; glucose and fructose were less effective; and rhamnose was entirely unable to support germination. Embryos detached from dormant seeds, incubated with the sucrose plus KNO3, germinated more rapidly with increasing temperature up to 35°C. However, application of sucrose and KNO3 did not induce germination of intact seeds above 26°C. Therefore, it is very possible that the endosperm exerts an inhibitory function on germination at such high temperatures. When seeds were incubated after a cut was made over a small part of the edge of the endosperm in which the radicle of the embryo is encased, germination occurred rapidly but the increase in germination percentage was slight. This result suggests that the endosperm suppots part of the germination inhibition by means of a mechanical barrier or its impermeability to water or gases. Physiological features of the endosperm alone or interactions between the embryo and endosperm may contribute significantly to the characteristics of dormancy of intact seeds of this species.Keywords
This publication has 2 references indexed in Scilit:
- Seed Dormancy in Red RicePlant Physiology, 1983
- Dormancy inDioscorea: Differences of temperature responses in seed germination among six Japanese speciesJournal of Plant Research, 1982