乌桕种子休眠原因及解除方法研究

Study on the causes of Sapium sebiferum seed dormancy and the methods for dormancy breaking

对乌桕种子的休眠原因进行了研究,发现乌桕种皮具有较好的透水性,所以种皮透水性不是造成乌桕种子休眠的主要原因。通过乌桕种子的离体胚发芽实验,证实乌桕种子的胚在离体条件下没有休眠现象;而乌桕种子的种皮及胚乳浸提物对种子发芽有显著抑制作用,所以乌桕种子的种皮及胚乳存在发芽内源抑制物,这可能是造成乌桕种子休眠的主要原因。另外,利用浓硫酸处理不能解除乌桕种子的休眠,直接低温层积也不能彻底打破乌桕种子的休眠;激素处理可有效解除内源抑制物造成的种子休眠,且通过比对实验发现,先用500或1 000 mg/L赤霉素处理,再层积100 d能有效打破乌桕种子的休眠。

In this paper,systematic study was conducted to explore the causes of seed dormancy in the Chinese tallowtree（Sapium sebiferum（Linn.） Roxb.）.Other than the early reports,coats of the tallowtree seeds were found to have good water permeability,which suggested that seed coats were not the main cause that inhibited the seed germination.Meanwhile,germination test indicated that in-vitro embryo of tallowtree seeds didn＇t undergo dormancy.However,extracting solutions of the seed coat and endosperm could suppress seed germination significantly,which implied the existence of endogenesis germination inhibitory substances in the corresponding seed parts.Based on these findings,we proposed that inhibitory substances could be the main reasons that caused tallowtree seeds dormancy.The tests of breaking tallowtree seed dormancy showed that： dormancy of tallow tree seeds could not be broken by both treatment with concentrated H2SO4 and the cold stratification method.However,by testing with different gibberellic acid solutions,dormancy could be overcome by soaking the seeds in 500 or 1 000 mg/L GA3 followed by 100（GA3） days stratification.