外生菌根对欧洲赤松苗(Pinussylvestris)Cu、Zn积累和分配的影响

通过测定２种不同施锌和施铜水平下苗木和离体菌丝中铜锌含量研究了接种外生菌根（Ｓｕｉｌｌｕｓｂｏｖｉｎｕｓ）对欧洲赤松（Ｐｉ－ｎｕｓｓｙｌｖｅｓｔｒｉｓ）苗生长和微量元素积累和分配的影响． 结果表明菌丝的侵染增加了苗木生长同时也增加了植物体内重金属的含量．然而菌根植物中的重金属大部分分布在根部在铜处理中菌根植物地下部分的铜含量是无菌根植物的２．６倍在锌处理中锌是无菌根植物的１．３ 倍． 说明菌丝侵染使植物将过量的重金属滞留在根部从而增加了植物对过量重金属的抗性．通过进一步测定培养在过量重金属中的离体菌丝的重金属含量结果显示随着外界重金属浓度的增加菌丝分泌物内重金属含量比菌丝内重金属含量增加快说明滞留在根部的重金属可能并没有进入根系而是以某种形态滞留在菌丝分泌物和菌丝内．

Accumulation and Distribution of Cu and Zn in Mycorrhizal Pinus sylvestris and Its Associated Ectomycorrhizal Fungus Suillus bovinus Exposed to Elevated Cu and Zn Concentrations in Cultivating Substrate

Seedlings of Pinus sylvestris infected with ectomycorrhizal fungi Suillus bovinus were exposed to various external Cu and Zn concentrations separately.The isolated ectomycorrhizal fungi Suillus bovinus were cultivated in the elevated Cu and Zn concentrations nutrient solution as well.The effects of mycorrhizal association on Cu and Zn accumulation and distribution within plant and in the isolated fungi mycelia culture(nutrient,mycelia and fungi slim)were determined by atomic absorption spectrometry.The results showed that mycorrhizal infection increased both biomass and contents of Cu and Zn of seedlings.However,excess Cu and Zn were accumulated in the root system.Treating with external Cu and Zn separately,Cu concentration was 2.6 times in the roots of mycorrhizal seedlings compared with non mycorrhizal ones and Zn was 1.3 times.These data indicated that mycorrhizal symbiosis increased the capacity of heavy metal depot in roots of host plant,therefore increased the tolerance of host plant to elevated heavy metal in environment.Determining the isolated fungi,the results showed that the contents of Cu and Zn were increased with the increasing of concentration of them in nutrient solution.Comparing with fungi mycelia,the increase of content of heavy metals in fungi mycelia slim was greater,that suggested that the heavy metals depot in root system probably were not translated into plant roots but sequestrated in fungi mycelia and mycelia slim.