Abstract:

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.

Key words: Vesicular-arbuscular mycorrhizal fungi, Poplar, Dothiorella gregaria, Canker resistance