VA菌根真菌提高杨树抗溃疡病机制的研究(英文)

MECHANISM OF VESICULAR ARBUSCULAR MYCORRHIZAL FUNGI ENHANCED RESISTANCE OF POPLAR TO CANKER

:本文研究了VAM (VesicularArbuscularMycorrhizae)真菌诱导北京杨 (Populus‘Pekinensis’Hsu .)树皮中生化指标的变化与其抗溃疡病的关系。结果表明 ,菌根侵染率与宿主树皮中的相对膨胀度、过氧化物酶和多酚氧化酶的活性、有效磷和总酚的含量呈显著正相关 ,与可溶性总糖呈负相关 ;而杨树溃疡病菌 (Dothiorel lagregaria)的生长与上述各生化指标的相关性相反。这说明VAM真菌不能够显著地促进杨树对水分的吸收 ,使杨树的树势得到增强 ,而且VAM菌能够通过诱导杨树树皮中过氧化物酶和多酚氧化酶活性的增强、总酚和有效磷含量的增加和可溶性糖含量的降低 ,减轻溃疡病菌对杨树的危害。VAM真菌提高杨树抗溃疡病的机制为 :VAM真菌通过与杨树的共生 ,从而改善杨树营养和水分状况 ,促进杨树对水分和养分 (主要是磷 )的吸收 ,增强树势 ,间接地提高杨树对溃病的耐病性。同时 ,与杨树共生的VAM真菌直接参与杨树生理生化代谢 ,诱导杨树抗性酶活性提高 ,增强杨树生化抗病物质 (酚类、木质素、苯丙基化合物等 )的含量 。

Biochemical index changes of Populus ‘beijingensis’ bark induced by the formation of associations with vesicular arbuscular mycorrhizal(VAM)fungi and their ralation to canker resistance were studied. The results showed that mycorrhizal formation was positively correlated with relative turgidity, enzyme activities(peroxidase and polyphenoloxidase), available phosphorus and total phenolic content of bark, but negatively correlated with total soluble sugars in bark. The growth of Dothiorella gregaria was negatively correlated with VAM formation. VAM fungi increased canker tolerance of poplars by promoting the uptake of water and nutrients(mainly phosphorus), which in turn increased the growth and vigor of trees. Induced peroxidase and polyphenoloxidase activities of poplars should result in increases in substances such as phenolics which are likely to be important parts of the canker resistance mechanisms of poplars.