濒危植物银杉根际微生物群落动态变化研究

A Preliminary Study of the Dynamic Variation of Rhizosphere Microorganism Communities of the Endangered Plant Cathaya argyrophylla

通过定点取样的方法对银杉根际微生物群落结构进行了研究,研究内容包括根际微生物和非根际微生物的类群和数量、不同季节根际微生物的变化动态、不同海拔梯度和不同土层深度根际微生物的群落变化动态等.研究结果表明:①银杉根际微生物中的细菌在数量上比放线菌和真菌至少高1个数量级,银杉的根际微生物在数量上至少较其他松科植物相差1～2个数量级;②不论从类群数量还是个体数量上,银杉的根际微生物总量都远低于其他松科植物,这可能是导致银杉退化和生长不良的原因之一;③根际微生物的总量随海拔梯度没有明显变化,随土壤深度呈现出明显递减的趋势;④不同季节根际微生物的总量差异不显著,根际微生物总量较非根际微生物多.

Fixed-point sampling was made in a preliminary study of the community structure of rhizosphere microorganisms of Cathaya argyrophylla to investigate the populations and and the non-rhizosphere microorganisms, their inter-seasonal variation, and t qu he antity of the rhizosphere dynamic variation in ferent altitudes and in different soil layers. The results showed that of the rhizosphere microorganisms of C. argyrophylla studied, the number of bacteria was at least one magnitude greater than that of actino mycetes and fungi and that the number of rhizosphere microorganisms of C. argyrophylla was at least one to two magnitudes lower than that of other Pinaceae species. Total amount of rhizosphere microorganisms of C. argyrophylla was much lower than that of other Pinaceae species, as expressed either in the number of populations or in the number of individuals, which may be one of the reasons that leads to the degrada tion and poor growth of C. argyrophylla. Total amount of rhizosphere microorganisms of C. argyro phylla changed little with elevation gradient but decreased conspicuously with soil depth. Total amount of rhizosphere microorganisms of C. argyrophylla was always greater than that of non-rhizosphere showed no significant difference in different seasons, but microorganisms.