Permalink : http://hdl.handle.net/2115/77404

KEYWORDS : Sandersonia aurantiaca;seed germination;seed coat;light;morphophysiological dormancy

Seed germination in Sandersonia aurantiaca is unstable and the requirements for germination are still unclear. We investigated requirements for germination using a broad range of treatments. The small embryos of S. aurantiaca seeds suggest morphophysiological dormancy(MPD),thus we also examined MPD levels in S. aurantiaca seeds. Radicles emerged from 18.8% of seeds without seed coat in light condition. In contrast,95% of the seeds incubated in darkness produced radicles. In darkness,radicles emerged from only 1.3% of seeds with seed coat and from 60% of seeds without seed coat. In seeds without seed coat incubated in darkness,radicles emerged from 30% of seeds incubated at 30/20℃ (alternating temperature)following a low temperature(cold stratification)at 5℃, but not from seeds at 35/25,25,or 30℃ following at 5 or 10℃. In seeds without seed coat incubated in darkness,regarding the effect of low temperatures(5℃ and 10℃)before high temperatures,radicle emergence seemed to be higher in 5℃ treatments than 10℃. These results indicate that S. aurantiaca seeds require removal of the seed coat,incubation in darkness,and low temperature to germinate. Radicles emerged,on average,from 40-70% of seeds without seed coat incubated in darkness at 5℃ for 90 days followed by at 30/20℃. Furthermore, low temperature was required for embryo growth and radicle emergence at subsequent high temperature. Shoots emerged from more than 80% of the seeds with radicles at 30/20℃ and at 20℃ or more. These show that seeds of S. aurantiaca have non-deep simple morphophysiological dormancy.