Physiological And Biochemical Characters Of Drought Resistance For Different Transgenic Wheat Strains By The DREB Gene

This study was conducted from 2007 to 2008 at the experimental farm of Shandong Agricultural University. The experimental plots are surrongded by trees. Transgenic strains was used for test materials, which are got from Lumai 23 by adding the DREB transcription factors and chooses Lumai 23 to be the contrast, different irrigation regimes (normal irrigation and none irrigation during the whole growth period) were introduced. The influence of DREB on physiological and ecological characteristics of wheat in drought, by comparing the differences of physiological and biochemical response of diverse wheat strains in growth. This experiment mainly shows:1. Comparison in different strains of wheat yield and its componentsUnder normal irrigation, there are less differences between transgenic strains and CK in wheat yield,No. of ears per 667m2,grain per ear and 1000-grain weight. On the other hand, under none irrigation, No. of ears per 667m2,grain per ear are far less than the former, but 1000-grain weight rises. Comparing with the contrast, the discrepancies are not obvious in grain per ear, but remarkable in No. of ears per 667m2 and 1000-grain weight. 2. The influence of different irrigation on wheat physiological and biochemical indexesDifferent water treatments causes significant influence on wheat growth. Under drought, the water percentage, water potential, the content of chlorophyll, photosynthetic rate, transpiration rate were lower and antioxidant enzyme activity of wheat plants were higher than those under normal irrigation and accumulate large amount of MDA, accelabrated senescence, shorten Photosynthetic duration, and decreased activities of enzymes involved in starch synthesis in grain, all of these led to reduced wheat grain yield.3. Comparison of different wheat strains in physiological indexes under different water treatmentsUnder normal irrigation, there are no significant differences in the content of chlorophyll, photosynthetic rate, transpiration rate, water percentage, and water potential between different wheat strains . While under drought, especially in the middle and later period of grain-filling, physiological indexes of transgenic strains are higher than that of the contrast. The osmotic adjustment ability is better in transgenic wheat plant after anthesis, particularly 21 days after anthesis, which is 72.4% and 51.5% higher in strains T43 and strains T47 than that in the contrast, respectively. Thus, it can maintains a low water potential and transpiration rate, delayed dehydration , prolonged photosynthetic duration, and provides more photosynthate for starch synthesis in grain.4. Comparison in different wheat strains of biochemical indexes under different water treatmentUnder drought, transgenic strains accumulate more free-proline than CK to maintain normal turgor pressure and guarantee water supply, so as to provide the relatively stable environment for keeping the normal physiological activities in drought conditions. Meanwhile, antioxidant enzyme activity of transgenic strains is relatively higher, especially in later grouting, it is significantly higher than that in the contrast. That can remove active oxygen in time, maintain normal physical structure of cells, slow down enzymes involved in starch synthesis in grain Inactivation rate, prolong the time of grain starch synthesis. Finally, in drought processing, accumulation of starch in T43 which has higher yield is 9.7% higher than that in the contrast, that lays the foundation for the high yield.5. Comparison in different wheat strains of water productivity under different water treatmentIn normal processing, the discrepancies of different wheat strains are not significant in water operating factor. But in drought, efficiency of water application of T43 is 12.7% higher than the contrast, and T47 is 16.6% higher.