松树感染云南半帚孢后韧皮中酶活性变化

云南松和华山松在感染纵坑切梢小蠹伴生菌———云南半帚孢后,体内与抗病性相关的过氧化物酶(PO)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)的活性均明显升高 云南松自身的抗性酶活性较华山松的小,在感染后,酶活性的增加较弱,持续时间也较短,在感染的最初7d酶活性增加迅速,而后活性增加趋于平缓;华山松自身的酶活性较大,感染后增加的幅度较大,比云南松迅速,且在试验期内一直持续增加 因此,总体上,云南松的抗性较华山松的弱 这也是云南境内云南松蠹害严重,而华山松蠹害轻微的重要原因之一

Variation of Some Enzyme Activities in Pine′s Phloem Infected by Leptographium yunnanense, A Fungus Associtated with Tomicus piniperda

Pine′s resistance to the beetles and its associated fungus is an important factor for regulating the level of tomicus attacks. After infecting the Leptographium yunnanense,a main fungus associated with Tomicus piniperda attacking Pinus yunnanensis,the enzyme activities of peroxidase(PO),polyphenol oxidase(PPO)and phenylalanine ammonia lyase(PAL) that existed in the phloem of host tree,which are related to the tree′ resistance,will increase distinctly and may maintain a longer time, thus the tree could constrain or poison the intruded fungus. And there is an important correlation between the tree′s resistance and these enzymes′ activities,the higher these enzymes′ activities are and longer the enzymes′ activities maintain,the stronger the tree′s resistance to the fungus is . The activities of PO, PPO and PAL in phloem of P. armandi are higher than that of P.yunnanensis,and can maintain a longer time after being infected. So the resistance of P.armandi is higher than that of P.yunnanensis. Therefore,it′s difficult for the beetles and its associated fungi to intrude and breed in P.armandi successfully,so the beetles and its associated fungi are tend to select P.yunnanensis as their host. And this is an important reason for Tomicus piniperda attacking P.yunnanensis very serious,but rarely attacking P.armandi.