Delay of flowering in the biennial Cirsium vulgare: size effects and devernalization
Delay of flowering in the biennial Cirsium vulgare: size effects and devernalization
复制标题
两年生蓟开花延迟：尺寸效应和去春化
作者：
P. Klinkhamer;T. D. de Jong;E. Meelis
延迟开花是小蓟自然居群中的一种普遍现象。在所有年份中，超过45%的至少一岁的轮虫推迟繁殖。开花的概率增加（按重要性顺序）增加的大小，在此期间的增长之前，立即抽薹，和年龄。与一般认为只有大型植物才在冬季春化的观点相反，我们证明了在C。vulgare所有的个体都可以在冬季春化。从二月的田间采集的最小大小的类的Roxanthus，在最佳条件下放置时显示80%开花。我们认为，在C。vulgare在春化时没有大小要求，但如果植物在5月未能达到抽苔所需的最小大小（可能是由长日照引起的），则开花延迟。
Delay of flowering is a common phenomenon in natural populations of Cirsium vulgare. In all years more than 45% of the rosettes that were at least one year old delayed reproduction. The probability of flowering increased with (in order of importance) increasing size, growth over the period immediately prior to bolting, and age. In contrast with the general idea about biennials that only large plants are vernalized during winter, we show that in C. vulgare all individuals can be vernalized in winter. Rosettes, from the smallest size-classes, collected from the field in Februari showed 80% flowering when placed under optimal conditions. We argue that in C. vulgare no size requirement exists at the time of vernalization but that flowering is delayed if plants fail to attain a required minimum size for bolting (probably induced by long days) in May.