鹅掌楸种群间光生态适应性的分化

DIFFERENTIATION OF LIGHT ECOLOGICAL ADAPTABILITY AMONG POPULATIONS OF LIRIODENDRON CHINENSE IN THE PROCESS OF BEING ENDANGERED

通过对鹅掌楸７个不同种群幼苗的光合生长年进程、光合速率、光饱和点和光补偿点，以及不同光生境条件下的叶绿素含量和叶绿素ａ／ｂ比值的实验测定和生长量的统计，结果表明，种群间存在明显的光生态适应性分化。该物种地理分布上的西部亚区种群的光合适应能力和生长势总体上强于东部亚区的种群。而在西部亚区中又以金平、盐津种群的适应力和生存力更强。本研究支持该物种种群的生存能力由西向东逐渐下降，居于东部亚区中的种群其濒危程度更为严重的观点。这种濒危过程中的生态适应性的分化，说明该物种的濒危，在很大程度上是“致危生境”造成的。

Seasonal courses of photosynthetic rate,light saturation point and compensation point and chlorophyll contents of seedlings of seven provenances of Lirodendron chinense under different ecological conditions have been measured.Results indicate that the differentiation of the light ecological adaptability has been occurred to ascertain extent among populations of the species.The adaptability and growth potentiality of populations distributed in the western subzone are stronger than those in the castern subzone.Among the populations in the western subzone,provenances of JP and YJ were of stronger than other in adaptability and survival ability.This study supports the concept that the survival ability of the species is gradually getting lower among the populations distributed from west to east, which means that the populations existed in the eastern subzone are often more endangered.This sort of differentiation of ecological adaptability during the process of endangering of a certain species implies the reason that it was to a great extent the “endangering habitat” that made the species to be endangered.