光竞争条件下邻域效应对植物高生长可塑性的影响

构建了以个体为基础,空间明晰的"影响域"模型来研究植物高生长对局域光竞争的可塑性反应.结果表明:植物个体会将其高度维持在一最优值以使其适合度最大,这一最优高度值会随着植物个体所经受的局域光竞争强度的增加而增大.种群中小个体相对于大个体能更早地将其高度维持在最优值,但小个体由于邻域光竞争强度过大而导致的不能继续维持在最优高度及随后的死亡过程也比大个体要早.这种植物个体间高生长可塑反应的不同步性是由于个体的局域光竞争环境存在差异而导致的.研究表明空间分布与邻域效应对植物种群中多样性的高度和高生长策略的产生具有重要意义.在植物高生长的可塑性研究中,忽略邻域效应的"平均作用"博弈理论模型往往会导致片面的,甚至是错误的结论.

Impact of neighborhood effects on adaptive plasticity of plant height under light competition environment

The adaptive plasticity of plant height to light competition was investigated using a spatially explicit, individual-based plant competition model based on overlapping zones of influence. The conclusions reached are that plant should maintain its height at an optimal value in order to maximize its growth rate and this optimal height increases with the increase of the intensity of neighborhood light competition endured by the individual plant. The persistence of individual plant at this optimal height starts earlier and ends earlier for small plants than large plants, and the death process starts first for the small plants within the stand.This asynchronism of adaptive plasticity of plant height to light competition is due to the variation in local light environment among individual plants. Our results argue strongly for the importance of neighborhood effects in generating the diversity of adaptive plasticity of plant height and height growth strategy in plant population. The "mean-field" game-theoretical model is defective and even misleading for understanding of adaptive significance of plant height because it does not consider the neighborhood effects.