Yamauchi Atsushi
Ocean Research Institute, University of Tokyo, Minamidai 1-15-1, Nakano, Tokyo, 164, Japan.
Evolution. 1996 Oct;50(5):1795-1807. doi: 10.1111/j.1558-5646.1996.tb03566.x.
The amount of available resource can be considered to restrict mast seeding behavior in plants, regardless of the cause of masting itself. The reproductive strategy of a plant that has stopped growing, but continues to maintain a constant size, is based on the allocation of assimilated resources between reproduction and storage. If both plant death and population growth rates are constant, the plant strategy is dependent only on its own storage size. Conditions for the evolution of mast reproduction were analyzed under both constant and varying environments, from the view point of storage-size dependent strategy, which is influenced by three parameters: the advantage coefficient of mast seeding, β; the cost coefficient of delayed seeding, γ; and the assimilation rate, P. The model indicated that: (1) mast seeding evolves only with a greater than linear increase in reproductive success with effort (β > 1) under both constant and varying environments; (2) in mast seeding, a critical storage size, S *, occurs, above which plants utilize all storage for reproduction; (3) in a constant environment, S * increases with increasing β and P and/or decreasing γ; (4) concomitant with (3), an intermasting period, τ, also increases with increasing β and decreasing 7, but is independent of P; (5) in a varying environment, S * and the average of τ increase with increasing variance of the assimilation rate, P; and (6) concomitant with (5), the intermasting period has a certain probability distribution. In addition, reproductive synchrony within the population and the relationship between mast seeding and species diversity are discussed.
可利用资源的数量可被视为限制植物的大年结实行为，无论大年结实本身的原因是什么。已停止生长但继续维持恒定大小的植物的繁殖策略，是基于同化资源在繁殖和储存之间的分配。如果植物死亡率和种群增长率均保持恒定，那么植物策略仅取决于其自身的储存量大小。从受三个参数影响的依赖储存量大小的策略的角度出发，在恒定和变化的环境下分析了大年繁殖进化的条件，这三个参数分别是：大年结实的优势系数β；延迟结实的成本系数γ；以及同化率P。该模型表明：（1）在恒定和变化的环境下，只有当繁殖成功率随努力呈大于线性的增加（β>1）时，大年结实才会进化；（2）在大年结实中，会出现一个临界储存量大小S*，超过这个值，植物会将所有储存用于繁殖；（3）在恒定环境中，S随β和P的增加以及/或者γ的降低而增加；（4）与（3）相伴，大年间隔期τ也随β的增加和γ的降低而增加，但与P无关；（5）在变化的环境中，S和τ的平均值随同化率P的方差增加而增加；（6）与（5）相伴，大年间隔期具有一定的概率分布。此外，还讨论了种群内的繁殖同步性以及大年结实与物种多样性之间的关系。
