Study On The Relationship Between The Physical Structure,Enzymatic Activities And Fruit Shrink Disease Resistance In Different Jujube Varieties

This study aimed at clarifying the related physical and chemical factors of fruit shrink disease resistance in different jujube varieties, as well as providing a referential biochemical marker for researching the fruit shrink disease resistance mechanism and identifying disease resistant variety. The author surveyed the jujube fruit shrink disease incidence in Liangzhuang, Nanzhai and Cangzhou. During the growing period of jujube, the fruits of different jujube varieties with different fruit shrink disease resistance were collected regularly, and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and phenylalanine ammonialyase (PAL), as well as total phenols and proline levels in the jujube fruits were also tested. Meanwhile, their stomatal densities, cuticle thicknesses, epidermis thicknesses and pulp structures in white ripe season of jujuba were measured. Further, indoor inoculation experiments were conducted in order to compare the variations of SOD, CAT, POD and PAL activities in different varieties fruit after inoculation.The results showed that there were apparent variations in field investigation of different jujube varieties. The jujube fruit disease resistance, related to pulp structure and cavity distribution, had a positive correlation with cuticle thickness and epidermal thickness. At a certain degree, a positive correlation between SOD activity and variety resistance, and a negative correlation between POD activity and variety resistance were observed obviously. However, the relationships between CAT, PAL activities and variety resistance had significant differences on the basis of field and indoor inculation experimental results. According to the biochemical substances contents assays, the total phenols content and variety resistance was correlated positively, while the proline content and variety resistance was correlated negatively. Therefore, the physiological indicators, i.e. peel thickness, SOD, POD and total phenols content, could be used to identify the species resistances.