| Spring frost impacts young ear's growing and results in a diminished yield in wheat (Triticum aestivum L.). Many studies indicate that anther connective formation phase is the low temperature sensitive phase in spring. Although a few investigations have studies the physiological mechanism of low temperature stress in wheat,the physiological characteristics,the relationships between these physiological indices and grain yield were not completely clear. To dissect the change of physiological indices,correlation and their grey relational grade with yield in wheat after low temperature stress at anther connective phase,this study choose 8 wheat varieties with different resistance to spring frost for experiment,all of them were cultivated with pots in field and low temperature treatment at anther connective phase. The results showed that after low temperature stress at anther connective phase,yield per plant decreased significantly with an average of 68.4%. Huaimai20,Wanmai38,Xinong979 and Aifeng 3 had a small drop (<65%) ,Shanmai139,Zheng366,Xiaoyan22 and Zhengmai9023 had a larger drop (>70%). Huaimai20,Wanmai38,Xinong979 and Aifeng 3 showed resistance in a better performance. Meanwhile,the content of malondialdehyde (MDA),proline and soluble protein,the activities of superoxide dismutase (SOD) and peroxidase (POD) in leaf increased differently after low temperature stress at anther connective phase. Huaimai20,Wanmai38,Xinong979 and Aifeng 3 had a smaller increase of MDA content than the average,and a larger increase in activities of SOD,POD and contents of proline,soluble protein than the average. Their cytomembranes showed a low degree of damage and a strong cold resistance. Under the low temperature stress,significant and negative correlations were observed in MDA content with other physiological indices,and the correlation coefficients ranged from -0.749 (P<0.05) to -0.883 (P<0.01); SOD,the POD activity and the contents of proline,soluble protein showed a significant and positive correlations with each other,the correlation coefficients ranged from 0.798 (P<0.05) to 0.963 (P<0.01). The gray relational grade analysis indicated that the contents of soluble protein,proline and the activities of SOD,POD had a higher relational grade,and connected closely with the grain yield per plant. Therefore,they were considered as important indices in the selection of spring frost tolerance in wheat. |
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