| The tests were conducted in 2006~2009 in the forest areas of Wenyang village located in Jian'ou county, and huaqiao State-owned Forest Farm in guang-ze county, Fujian Province. In order to prove up relationship between potassium(K) and the Resistance of Castanea henryi (Skan) Rehd.et Wils. Against Dryocosmus kuriphilus Yasumatus, the content of potassium(K) in the leaves of C. henryi undamaged and damaged by D. kuriphilus was determined, and the content of total phenols, tannin and flavonoid in the leaves of C. henryi applied by potassium (K) fertilizer was also compared with those unapplied fertilizer. The main results were summarized as follows:1. During the larval damage main period, overwintering larval period of D. kuriphilus, when the content of potassium (K) was higher than the treshold, clone plants showed stronger resistance with the pest. So the resistance of C. henryi to D. kuriphilus can be identified by the content of potassium (K) in the leaves of the clone.2. With the overwintering larval period, it had a linear-regression relationship between resistance index and the content of potassium (K) of C. henryi. The relationship was that the degree of resistance depend on the content of potassium(K). The content of potassium(K) was increased in high resistant clones when they were damaged by D. kuriphilus.3. During the overwintering larval period, the increase of potassium (K) in stronger resistant clones was achieved to resist the pest by reducing tannin 's content and producing phenols of relative molecular weight less than 500, not changing total phenols's content. During this process, the content of phenols increased, or unchanged. 4. During the larval damage period, after fertilizing the trees of these clones with potassium (K), the content of flavonoid did't significantly change in the leaces of trees of stronger resistant and medium resistant clones, but significantly increased in the leaces of trees of the susceptible clones. |
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