Germination of the photoblastic seeds of Ocimum tenuiflorum L.

Abstract

Seeds of Ocimum tenuiflorum L. are positively photoblastic. Photosensitivity of seeds spreads throughout the tested temperature range (14–38°C). Treatment with suboptimal and relatively supraoptimal temperatures before placing the seeds at optimal temperature led to an interesting germination pattern. Gibberellic acid, although causing the seeds to germinate in dark, failed to overcome the low temperature block to germination both in light and dark. Prolonged darkness induced skotodormancy in seeds. Low temperature and gibberellic acid alone or in conjunction with red light failed to restore light sensitivity. Most interestingly a prolonged continuous exposure to red light enabled the seeds to overcome the skotodormancy. Significance of this adaptation in perpetuation of the species in its natural environments is discussed.