Study On Structural Resistance To The Infection By Grape Phylloxera In Different Grape Species

In order to study the mechanism of constriction resistance in root to grape phylloxera, Grape of V.vinifera, V.america, rootstocks and wild grapes were used as material to investigate the relationship of the morphology,anatomy structure and organizational structure in these grape roots and their resistance to Grape phylloxera during 2006~2008. Materials were collected from Shandong agriculture university, Zhengzhou fruit research institute and experimental area of China- Moldova. This research will provide theoretical guidance for the grape cultivation and resistance breeding, lays the foundation for the further study to induced resistance, and provides basis for induced resistance and physiology resistance to Grape phylloxera. The main results were as follows:1. Susceptibility level of grape root to phylloxera was significant positive correlation with related to percentage and mass ratio of root bark, at the same time, the mass ratio of root bark was positive correlation with the percentage of root bark. The average of the percentage of root bark of V.vinifera-V.Americain and V.Vinifera varieties was all more than 0.70, on the other hand, the average of the percentage of root bark of resistance rootstocks is less than 0.60. Grape root tend to succulent root with the percentage of root bark increased, meanwhile, the grape were susceptible to grape phylloxera.2. Resistance level of grape root to phylloxera was significant positive correlation with the cellulose content, lignin and pectin, whose interrelating coefficient were 0.945,0.796,0.781 respectively. Among which, Rootstocks had highest cellulose content, lignin and pectin, and Chinese wild grapes, V.vinifera-V.Americain and V.Vinifera had the lowest content. The contents of cellulose and pectin declined 24 days after inoculation, while the order for the absolute value of cellulose and pectin lead is: 140Ru>Xiongyuebai>Tamina. Cellulose, lignin and pectin are cell wall components, and the resistance level to grape phylloxera was positive correlation with the contents of cellulosea, lignin and pectin in grape roots. 3.Resistance level of grape root to phylloxera was closely related to anatomical structure, anatomical structure were showed as the volume, layers, arrangement of cork layer cells and the volume, arrangement of cortex cells. The three V.vinifera and Kyolo had five cork layer cells, and these cells were quadrate without protuberance in the periphery; V.amurensis-V.vinifera, the Wild grape Beta and Huajia No.8 had seven cork layer cells, and these cells was quadrate with seldom protuberance in the periphery; Rootstocks had eight cork layer cells, and these cells were oval and most cortex cells have protuberance in the periphery; From V.vinifera-V.Americain, V.vinifera and V.amurensis-V.vinifera to rootstocks, the volume of cork layer cells becomes smaller in order, and the number of cork layer cell layers becomes larger in order, the arrangement of cortex cells becomes firmer in order, meanwhile, the same tend as the volume and arrangement of cortex cells, at the same time, the resistance to grape phylloxera becomes stranger with these changes in anatomical structure.4. Different varieties have different reactions after grape phylloxera infection, V.vinifera, V.vinifera-V.Americain, most of the wild resources and V.amurensis-V.vinifera would produced large numbers of nodosities and tuberosities; some wild resources, the rest of V.amurensis-V.vinifera and few rootstocks could produced some nodosities but no tuberosities; a majority of rootstocks could not produced any nodosities and tuberositie. The result of paraffin section showed that the nodosity formation was not caused by the number of plies of cortex cells increased, but by the distal cells of cortex increased in size; The tuberosity formation was caused not only by the number of cork cambium cells increased, but also by the volume of cells nearby the feeding site increased, whose volume could increased about 20 percent.5. The result of anatomy structure showed that the surface near the feeding site collapsed at the beginning of phylloxera infected, then the collapsed area enlarged and the cells near the feeding site was stunted, at the same time, the volume of the distal cells augments, as a result, the primary roots (especially nearby the root tip) became nodosities, which looked like bird's heads, and the phylloxera fed on the collapse area. The surface ofç²—æ ¹nearby the feeding site collapse a little at first, then, the cell numbers increased near the cork cambium and the cell size increased later on, and the orientation of these cells was vertical to the surface. As a result, the swelling appeared and tuberosities emerged at last.