The Drought Resistance Mechanism Of Spring Wheat In The Prophase Of Growth And Screening Of Resistant Resources In Heilongjiang Province

375 spring wheat varieties including synthetic hexaploidy wheat,wheat rare varieties , landraces and traditional and new wheat cultivars planted in Heilongjiang province were used to screen drought resistance resources and then study drought resistance mechanism. The drought resistance level of each spring wheat variety were determined by way of soaking it into the PEG-6000 solution (polyethylene glycol) during the germination period; To determine the drought resistance in seedling stage, 45 varieties with different types and drought resistance level were subjected with methodology of repeated drought treatments. Finally, some paramenters related to drought resistance of 14 varieties were measured. The study results showed that:1. There is no significant co-relationship between drought resistance at germination stage and seedling stage, indicating that drought resistance at different stage are controlled by different genes or loci.2. Drought treatment could make the dry matter weight of plant lower than that of normal check while significantly increase the ratio of root to shoot.3. With the strengthen of water stress, stoma opening degree of the 14 experimental materials (5 types) shows a decreasing trend, and lower than that of the standard variety in the same period. This phenomenon is especially obvious when the drought degree varies; With the strengthen of water stress, the compared water content of plants display a trend of decrease, and lower than that of the standard plant in the same period, especially when there is a drought; with the strengthen of water stress, the root system vitality shows a trend of increase, and even higher than that of the standard variety of the same period, especially when water stress increased.4. With the strengthening of water stress, the praline and propylene-aldehyde content of the 14 experimental materials (5 types) present an increasing trend, and even higher than that of the standard variety in the same period. The discrepancy is especially obvious when drought is serious (20%).5.The difference in drought resistance level of spring wheat depends on different physiological parameters. The drought resistance level of artificial synthetic hexaploid wheat depends on praline content, stoma opening degree, propylene-aldehyde content and root system vitality, all of which present the effect of biochemical criterion; the drought resistance level of rare speice depends on the stoma opening degree, propylene-aldehyde and praline content and dried plant weight, presenting the effect of biochemical criterion; the drought resistance level of peasant speice...