| Elymus canadensis L. were introduced from the United States, the tests found that it had good resistance to drought and salt. The study selected Elymus canadensis L. and Elymus sibiricus L., which is the type species of Elymus, as the materials, through simulated the different degrees of drought, and different concentration of NaCl, Na2CO3,to study the change of physiological and biochemical indexes of the Elymus canadensis L. and the Elymus sibiricus L.. Used the SSR markers to search the genetic distances of Elymus canadensis L. and Elymus sibiricus L.. Then studied the genetic relationship between two materials and the Triticum aestivum Linn.. To provide theoretical basis for importing the excellent resistance gene of the forage to the wheat .The main results asfollows:1. The genetic relationship between the Elymus canadensis L. and Elymus sibiricus L. Screened 46 primers from the chromosome of the Wheat, there were 33 primers were effectively. These primers expanded 1309 alleles, each primes could expand 32.7 alleles averagly.The SSR results showed that, the genetic similarity of the Elymus canadensis L. and Elymus sibiricus L. was 0.56, geography distant leaded the result. The genetic similarity between the Elymus canadensis L. and the Triticum aestivum Linn. was 0.76.The study also found that, the hybrid F1 of the Elymus canadensis and Elymus sibiricus L. was more closer to the female parent, Elymus canadensis . It's genetic similarity with the Elymus canadensis was 0.85, the genetic similarity with the Elymus sibiricus was 0.72. The genetic similarity between the Triticum aestivum Linn. and the F1 was 0.75, even higher than F1 and the Elymus sibiricus .2. The drought resistance physiological characteristics of Elymus canadensis and Elymus sibiricusUnder drought stress,the malondialdehyde increased was the initial response of Elymus canadensis and Elymus sibiricus,the MDA destroyed the function and structure of the membrane, then the conductivity increased. Remove peroxide of superoxide dismutase (SOD) increased, the chlorophyll degraded. As osmoregulation substance, the content of the proline and soluble sugar increased. The drought stress influenced the photosynthesis of two materials. The Pn,Tr and Gs decreased too. WUE increased. Gs decreased and WUE increased contemporary indicated that the photosynthetic rate reduced by non-stomata factors.3. The Salt-tolerant physiological characteristics of Elymus canadensis and Elymus sibiricusWhen the salt concentration was the lowest, malondialdehyde of Elymus sibiricus increased first, then the activity of the SOD increased. The variation of content of proline was the minimum. The original damage of the Elymus sibiricus was membrane damaged, the activity of the SOD increased. Then the Metabolic disordered, chlorophyll degraded. The membrane permeability increased. As osmoregulation substance, the content of the proline and soluble sugar increased.When the salt concentration was the lowest, conductivity of Elymus canadensis increased first, then the malondialdehyde increased. The variation of content of proline was the lowest. The original damage of the Elymus canadensis was membrane damaged, conductivity increased. Caused hurt material-MDA. Then the Metabolic disordered, chlorophyll degraded. As osmoregulation substance, the content of the proline and soluble sugar increased.Through different concentrations and time of salts stress, the Germination rate and the Germination index of Elymus Canadensis and Elymus sibiricus were declined. And they were significant negative related to the salt concentration. The relative salinity injuey rate were rised, and were significant positive correlation with the salt concentrationUnder different kinds of salts stress, though the variation trend of every physiological index of Elymus canadensis and Elymus sibiricus were the same. But the amplitude of variation were significance. The hurt of Na2CO3 were more intensity than NaCl. And the levies were more injured than the roots. So the roots could percept the stress quicker than the levies, to keep the plants alive. |
