二年生草本の生活史の進化

概要

論文の詳細を見る
Biennial plants often show a facultative life cycle. Facultative biennials determine the timing of their reproduction by plant size. In a stress-imposing environment they do not flower for more than 3 years until the rosette has reached a critical size. Although delayed reproduction usually lowers the population growth rate, it has several selective advantages. Firstly, delayed reproduction prolongs the period before extinction in declining populations. Secondly, under environmental conditions resulting in a lower fecundity, the optimal age of reproduction is delayed. Thirdly, in a fluctuating environment, facultative reproduction is more favorable than simultaneous reproduction, because size-dependently reproducing plants use a fluctuating environment as fine-grained. It is also advantageous to adopt size-dependent reproduction rather than age-dependent reproduction, since it can alleviate the damage of environmental stresses on population growth. Thus, it is reasonable that so many biennials show a facultative or size-dependent life history rather than an age-dependent life history.
日本生態学会の論文
1986-04-30