布氏稠李種子具有休眠性,在30/20℃下12星期不發芽。種子經低溫4℃濕層積處理12星期或用激勃素GA3濃度500 ppm處理,皆能促進發芽,但後者的平均發芽天數較前者長約40天,發芽速率較慢。利用氣相層析質譜儀定量分析種子內的離層酸與激勃素,新鮮種子的離層酸濃度很高,有476 ng (g Dw)^(-1)。然種子經暖溫層積或低溫層積處理後,離層酸濃度均降為原來新鮮種子的5%左右,且接近正在發芽種子的濃度。激勃素GA1, GA3, GA4和前趨物GA20濃度在種子經低溫層積處理後皆有增加,其中以GA1, GA3和GA20濃度增加最大。暖溫層積能降低種子內的離層酸濃度,但此時種子仍不發芽。低溫層積不但能降低種子內的離層酸濃度,而且增加激勃素濃度,使有活力的種子全部發芽。結論暗示離層酸濃度的下降與種子休眠的調節作用有關,但最後種子發芽啟動時更需要依賴激勃素的作用。
Freshly harvested seeds of Prunus buergeriana Miq. are dormant and have poor germination. Moist stratification of seeds at 4℃ for 12 wk or treating seeds with a 500-ppm GA3 solution promoted germination, but the mean germination time with the latter was about 40 d longer than that of the former, indicating that the germination rate of the latter was slow. Concentrations of abscisic acid (ABA) and gibberellins (GAs) were measured by GC-MS-SIM in fresh seeds, warm-or cold-stratified seeds, and germinating seeds. Fresh seeds contained a higher concentration of ABA of 476 ng (g DW)^(-1), but the concentration of ABA declined to 20-times lower after warm or cold stratification and was close to that of germinating seeds. Cold stratification at 4 C increased the endogenous GA1, GA3, GA4, and precursor GA20, among which GA1, GA3, and GA20 showed greater increases. Warm stratification decreased the ABA content of seeds, but the seeds still did not germinate. Cold stratification not only decreased the ABA content but also increased the GA contents. We concluded that ABA is implicated in the regulation of seed dormancy, but the initiation of seed germination is more dependent on GAs.