Study On Resistant Physiological Mechanism Of Jujube Species On Jujube Witches' Broom

Zizyphus jujube, as one of the important economic trees, is planted widely in china. Jujube witches' broom (JWB) caused by phytoplasma, is becoming the most destructive systematic disease of Chinese jujube and has brought much economic damage to our country. In this paper, the pathogen detection and growth condition in the field of different ziziphus jujube cultivars were studied after grafted infected barks. In addition, on the physio-pathological aspect, the POD,PPO,PAL,IAAO enzyme activity, POD and IAAO isozyme in different zizyphus jujube cultivars bearing branch and the content of phenolic compounds , protein, amino acids, chlorogenic acids in leaves were also analyzed respectively, the main result were as follows:1. Zizuphus jujube may be infected by phytoplasma through graft transmission using disease barks. After grafted infected barks, almost all the jujube cultivars and single tree have phytoplasma through PCR detection. However, in Pozao and Hamazao healthy single tree leaves, the content of phytoplasma is relative lower, in Pozao and Suanzao disease single tree, higher; while in Hupingzao cultivars, both healthy trees and disease trees have high phytoplasma content. It can be concluded that there is no direct relationship between phytoplasma content and sympotom, what's more, different jujube cultivars may have different reaction to phytoplasma.2. Using ultraviolet spectrophotometry determining the enzyme activity of POD,PPO,IAAO,PAL in jujube bearing branch, the result showed that in the same cultivar, there is no significant difference among all the single tree on the enzyme change tendency. But in Pozao cultivar, the POD,PPO,IAAO enzyme activity of susceptible single tree are a little higher than resistant ones, the PAL enzyme activity lower than resistant ones. While in Hupingzao cultivar, the POD,IAAO activity of susceptible tree are higher than resistant ones, the PPO,PAL activity lower than resistant ones. This also indicated that different jujube cultivars may have different reaction to phytoplasma.3. The POD and IAAO isozyme of different jujube cultivars bearing branch were determined by using incontinous polyaerylamicle electrophoretic (PAGE) method. It showed that in Pozao cultivar, the PODJAAO isozyme band have obvious difference between susceptible trees and resistant ones in August, while in Hupingzao cultivar, there is no significant difference between susceptible trees and resistant trees.4. The phenolic content and chlorogenic acid content in different jujube cultivars leaves were studied , the result suggested that in the same strain , the phenolic content and chlorogenic acid content of resistant single tree are usually higher than susceptible ones. Comparing different cultivars also indicated the content of phenolic compound and chlorogenic acid in resistant cultivars and single tree are shortly higher than susceptible ones. Therefore, these two indexes may be used to study JWB.5. The content of protein and amino acid in different cultivars leaves were also analyzed. It indicated that in the same strain, the protein and amino acid content of susceptible trees are a little higher than resistant ones. Furthermore, all diseased cultivars protein content are higher than resistant ones. But the amino content has no obvious regularity.