Germination of seeds in Jussiaea suffruticosa

Seeds of Jussiaea suffruticosa reach high germination percentagesonly when exposed to long periods of continuous illumination.The light reaction may be repeatedly reversed by short exposuresto red and far red light, thus being mediated by the phytochromesystem. Seeds also germinate at high percentages if exposedto various cycles of 1 hr light and 24 hr of darkness at 20°C.If the temperature in the periods of darkness is raised up to30°C or lowered to 10°C the promotive effect of lightis inhibited. High temperatures (35°C) during imbibitionhave a promotive effect, whereas a pure O₂ atmosphere decreasesthe response to light. KNO₃ and kinetin enhance the responseto light but do not provoke germination in the dark. Only ifseed coats are punctured or removed does germination in thedark occur. (Received January 14, 1969; )