河南主推小麦品种对低温胁迫的生理响应及耐寒性分析

为探讨不同小麦品种对春季低温胁迫的响应,以郑麦366、郑麦7698、矮抗58等12个河南省主推小麦品种为试验材料,研究了拔节期低温(-6℃)和孕穗期低温(0℃)处理对不同小麦品种叶片生理指标、产量及其构成要素的影响,分析了寒害级别与各生理指标增幅之间的相关性。结果表明,幼穗发育进程慢的强耐寒性小麦品种的叶片中可溶性糖含量、可溶性蛋白含量、脯氨酸含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性在低温条件下的增幅大于幼穗发育进程快的弱耐寒性品种,丙二醛(MDA)含量的增幅表现出相反的趋势。拔节期和孕穗期低温处理,使供试小麦品种的有效穗数、穗粒数、千粒重以及产量均下降,拔节期低温对有效穗数和千粒重的影响更为严重,孕穗期低温对穗粒数和产量的影响更为严重。拔节期低温引起的小麦叶片可溶性蛋白含量、脯氨酸含量、SOD活性、CAT活性和MDA含量的增幅与小麦所受寒害级别呈显著或极显著相关;孕穗期低温引起的小麦叶片可溶性糖含量、可溶性蛋白含量、SOD活性、POD活性、CAT活性和MDA含量的增幅与小麦所受寒害级别呈显著或极显著相关。这些结果说明,不同小麦品种的耐寒性强弱在拔节期和孕穗期的表现并不一致,与寒害水平显著相关的生理指标也有差异,应结合两个时期的综合表现评价小麦品种春季的耐寒性。

Cold Tolerance Evaluation of Wheat Varieties in Henan Based on Their Physiological Response to Low Temperature Stress

To explore the response of wheat cultivars to low temperature in spring,twelve wheat cultivars widely planted in Henan were used to study the effects of low temperature during jointing and booting stages on spike number,grain number per spike,1 000-grain weight,yield and physiological indices of leaves and the correlation of the cold injury level with the physiological indices increment. The results showed that under cold stress,the increase rate of the content of soluble sugar,soluble protein and soluble proline and the activities of superoxide dismutase (SOD),peroxidase (POD),catalase (CAT) in strong cold resistant varieties with slower spike differentiation were larger than those in weak cold resistant varieties. However,the MDA content in leaves showed a reverse trend. The spike number,grain number per spike,1 000-grain weight and crop yield of twelve varieties decreased under low temperature stress. Cold had a more serious influence on the spike number and 1 000-grain weight at jointing stage but on the grain number per spike and yield at booting stage.Acording to the correlation analysis,it was demonstrated that the cold damage level was significantly correlated with the content of soluble protein,soluble proline,SOD activity,CAT activity and MDA content in leaves under low temperature at jointing stage. Besides,the cold damage level was significantly correlated with the content of soluble sugar,soluble protein and activity of SOD,POD,CAT and MDA content at booting stage. In conclusion,the cold tolerance level of twelve wheat varieties should be evaluated according to their response to low temperature stress at both jointing and booting stages because it didn't always show the same response for many varieties during the two stages and the appraisal indicators related to cold tolerance level were different in two stages as well.