青阳参种子的萌发

青阳参（Cynanchum otophyllum）种子在11月成熟时有休眠习性。收获后将其种子种植在自然温室内，到第二年的春天种子才会萌发，且大多数种子在3月28至4月4日间萌发，这期间的日平均最高和最低温度分别为19．0℃和9．9℃。层积能有效地打破青阳参种子的休眠，休眠种子通过大约1周的层积便能萌发。种子在有光的条件下层积1周后转移到25／15℃的黑暗条件下萌发率可达到75．4％。青阳参种子不论在有光的条件下还是在黑暗环境中层积2～3周后转入30／20和25／15℃进行变温处理，其萌发率最低能达到66．4％，而转入20／10℃变温处理其萌发率最多只能达到20．1％，但若层积6周，即便在20／10℃变温处理的情况下其萌发率也可以达到65．3％以上。

Seeds Germination of Cynanchum otophyllum (Asclepiadaceae) Endemic to China

Intact seeds of Cynanchum otophyllum were innately dormant at maturity in November. Seeds planted in a nonheated greenhouse in November germinated the following spring and most of the genmination occurred between 28 March 4 April, when the mean maximum and minimum daily temperatures were 19.0 and 9.9℃, respectively. Stratification was effective in overcoming dormancy, and nondormant seeds germinated in both light and darkness. About one week of stratification was effective in overcoming dormancy in some of the seeds; seeds stratified in light for 1 week and then incubated in darkness at 25/15℃ germinated to 75.4%. Seeds stratified in light or darkness for 2 and 3 weeks and then incubated inlight or darkness germinated to 66.4% or more at thermoperiods of 30/20 and 25/15℃ but germinated to 20.1% or less at 20/10℃. Seeds stratified for 6 weeks also germinated to high percentages (65.3% or more) at 20/10℃.