纵坑切梢小蠹伴生菌--云南半帚孢毒素作用机理的初步研究

用纵坑切梢小蠹伴生菌——云南半帚孢Laeptographium yunnanense的毒素处理后，云南松和华山松体内与抗病性密切相关的过氧化物酶、多酚氧化酶和苯丙氨酸解氨酶的活性都明显地下降，表明该毒素可以通过抑制寄主体内与抗性有关的酶的活性来削弱寄主的抗性，从而有利于菌在寄主体内侵染生长。云南松的酶活性下降的程度较大，而华山松的酶活性较高，毒素处理后活性受抑制的程度相对较小，这表明华山松对云南半帚孢的抗御能力较云南松的强，这也是云南境内云南松受害严重而华山松受害轻微的重要原因之一。

Action mechanisms of phytotoxin produced by Leptographium yunnanense associated with Tomicus piniperda

Leptographium yunnanense was the main pathogenic fungus associated with Tomicus piniperda attacking Pinus yunnanensis ,which could assist the beetles in overcoming the resistance of the host tree.The phytotoxin of L.yunnanense could restrain the activities of peroxidase(PO),polyphenol oxidase(PPO)and phenylalanine ammonia lyase(PAL) in the tree and thus reduce the resistance of the host tree and benefit the fungus to intrude into the tree successfully.The enzyme activities of Pinus yunnanensis was lower than that of P.armandi ,and restrained stronger by the phytotoxin,this indicated that the resistance of P.armandi was higher than that of P.yunnanensis .And this was an important cause of serious damage of Tomicus piniperda on P.yunnanensis ,while little damage on P.armandi in Yunnan Province.