Physiological Characters And The Expression Of Genes Related To Cold Resistance Of New Strain Of Trifolium Repens L.

In this paper,Trifolium repens L.cv.haifa,Trifolium repens L.cv.Riesling and a new variety of white clovers were used to analyze the cold tolerance of different varieties of white clover.Therefore,the characteristics of seed germination,the physiological characters of different growing stage including germination stage,seedling stage,and wintering period were determined.Furthermore,the result of experimental data analysis through variance analysis,relevance analysis and fuzzy subordinate function analysis showed that:1.The cold tolerance of new variety of white clover was significant higher than that of Trifolium repens L.cv.haifa and Trifolium repens L.cv.Riesling.For cold stress,the germination rate and germination index of the new variety were both higher than those of control.In addition,the activities of SOD,the content of soluble sugar and soluble protein of the new variety under cold stress were significantly higher than those of control.2.The new variety of white clover showed stronger cold tolerance during storage in field through the winter than control.With the decrease of temperature,the content of POD?SOD?CAT?SS?SP and PRO in the roots of the new variety of white clover were significant higher than those of control.Compared to control,the proline in the new variety increased fastest,while the content of MDA and REC were lower in the new variety.3.The results showed that the gene MYB4?CBF3 and CAS5 were all induced by cold stress.The expression level of CBF3 increased with the cold stress,while the expression level of MYB4 and CASS increased first and then decreased slowly.However,the expression levels of all the 3 genes in the new variety of white clover were higher than those of Trifolium repens L.cv.haifa,Trifolium repens L.cv.Riesling.The CBF3 showed the highest level,and MYB4 showed the lowest level.In sum,our results reveal the cold tolerance mechanisms of the new variety of white clover through physiological characters and the expression of genes related to cold resistance.