Germination behaviour of two morphologically different types of seed of Cassia tora at different temperatures

The effect of temperature on the germination response of two categories of morphologically different seeds of Cassia tora L. was investigated. Germination response of dormant seeds (category A with closed ultraastructures) was not affected by temperature, as 96% of the seeds germinated at all temperatures on scarification. On the other hand, non-dormant seeds (category B with open ultrastructures) were temperature sensitive and germinated best at 32°C. However, storage affected the germination responses of both types. While the category A seeds lost moisture gradually with storage time and retained viability for a longer period, i.e. 2 years, the moisture loss in category B seeds was noted only after 2 years and the seed viability was retained for only 1 year. The production of two morphologically and physiologically distinct types of seed simultaneously by C. tora is probably an ecological adaptation for progressive emergence of the species over long periods in the field.