Embryo development and seed germination of Hepatica nobilis Schreber var. japonica as affected by temperature after sowing

Seeds of Hepatica nobilis had a globular embryo when dispersed from parent plants. In seeds that were sown and cultivated in a non-heated polyethylene house, the globular embryos in the seeds developed into torpedo-shaped embryos by week 9 of cultivation. The development of the torpedo-shaped embryos was remarkably retarded when the average weekly temperature was more than 23.5-25degreesC, and then resumed at temperatures below 20degreesC. Embryos developed into a cotyledon shape by week 25 of cultivation and the radicle emerged from 75% of seeds by 29 weeks after sowing. TO test effects of temperature on development of embryo and seed germination, seeds were cultivated in incubators at different temperatures. Globular embryos developed into torpedo-shaped embryos by week 7 at 15 and 25degreesC, while embryos in seeds at 4degreesC scarcely developed. Seeds maintained at 15degreesC developed and then germinated, whereas embryos in seeds held at 25degreesC remained torpedo-shaped. (C) 2003 Elsevier B.V. All rights reserved.