Study On The Resistance-Related Physiological Parameters Of The Resistance Of Populus Tomentosa To Apriona Germari

To explore the mechanism of the resistance of forest tree to insects and breeding new species with resistant is the foundation of Poplar Longhorn Beetle Integrative Management. In recent years, research of the mechanism of physiology resistance of poplar to longhorn beetle mainly focused on water metabolizing, primary metabolizing and secondary metabolizing as well. The common viewpoint is that poplar is insect-resistant when water content is higher, while insect-attacked when nutritious material content is higher. Secondary material is generally considered as tightly related to resistance and it will be insect-resistant when secondary material content is higher. The research result is usually different even contrast because secondary material is volatile and difficult to be measured.The pathway of insect-resistant breeding is to take full use of the genetic resource of poplar and analysis the resistant material. So that explore the physiological mechanism of resistance and find out the key38factor. The routine breeding methods should be combined with modern biological techniques to locate the resistance-related gene and multi generation breeding.Li etc. studied the relationship of bark inclusion in the clones of Populus tomentosa and the resistance to Apriona germari. Considered that the content of amino acid, total sugar and tannin influence the resistance. Sang's research shows that the life, capacity of eating and amount of oviposition of Apriona germari adults are notably varied when feed with 4 different forest tree species. The variation of resistance is caused by the different content of reducing sugar, amino acid, tannin and total phenolic as well.On the basis of these research work, this article select 5 insect-resistant and 5 insect-attacked Populus tomentosa clones among 371 clones and measured some guideline of water metabolize, primary metabolize and secondary metabolize. Measurement was done on the content of water, total nitrogen, total kalium, total phosphor, chlorophyll, total sugar, total phenolic, tannin and the activity of POD and PPO as well.The result show that those clones with higher water content is insect-resistant. Clones with higher content of total nitrogen and kalium are insect-resistant. The content of total phosphor and chlorophyll has no effect on resistance. The content of total sugar has no influence of the39feeding habit of adult insects, and is not notably varied among the clones. The content of total phenolic and tannin could be important guideline for resistance. The activity of PPO is tightly related to resistance. POD will be more active when the clones are attacked, which is response of poplar to insects.The author take it that the physiological mechanism of forest tree is a complex system which is controlled by heredity. The influence of secondary metabolize is more directly. The activity of PPO is considered to be a key factor of resistant research. Further study should be focused on the heredity law of PPO and improve poplar species compositively with the combine of modern biological technique.