拔节期低温胁迫对小麦生理特性和产量的影响

Effects of Low Temperature Stress on Physiological Characters and Yield of Two Wheat Varieties at Jointing Stage

为明确拔节期低温胁迫对小麦生理特性和产量的影响,以周麦18和众麦1号为材料,利用人工智能温室模拟0℃低温胁迫,测定了试材在低温胁迫24 h和48 h后的气体交换参数、叶绿素荧光参数、生理指标和单株产量相关性状。结果表明,小麦品种的耐低温特性存在基因型间差异,众麦1号的耐低温特性显著优于周麦18。低温胁迫处理后,2个小麦品种的气体交换参数、叶绿素荧光参数Fv/Fm和q P值、叶绿素含量均显著降低,众麦1号的降低幅度显著低于周麦18,其中低温胁迫24 h后,两品种的净光合速率较对照处理分别降低36.47%和30.91%,48 h后分别降低57.00%和49.18%;叶绿素荧光参数NPQ、脯氨酸含量、可溶性蛋白含量均显著上升,众麦1号的上升幅度显著高于周麦18;SOD、POD、CAT酶活性呈现先升后降的趋势,众麦1号的上升幅度高于周麦18,而下降幅度小于周麦18;周麦18和众麦1号的单株产量显著降低,低温胁迫24 h后周麦18和众麦1号的单株产量较对照分别下降31.00%、19.09%,48 h后分别下降56.85%、46.59%,低温胁迫主要影响了单株穗数和单穗粒数。综上,低温胁迫下众麦1号可积累更多的脯氨酸和可溶性蛋白,同时具有较高水平的抗氧化酶活性,可减轻逆境下小麦受伤害程度,维持较高的光合效率并获得较高的产量,这是其具有较好耐低温特性的原因。

In order to explore the effects of low temperature stress on physiological characters and yield of different wheat varieties at jointing stage,we took two wheat varieties named Zhoumai 18 and Zhongmai 1 as materials,and treated them in an artificial phytotron under low temperature（0℃） stress. The gas exchange parameters, chlorophyll fluorescence parameters, biochemical indexes and yield characters were determined after 24 h and 48 h. The resuks showed that two wheat varieties had different tolerance to low temperature,and the tolerance of Zhongmai 1 was better than Zhoumai 18. After low temperature stress, the inhibition degree of gas exchange characters,maximum photochemical efficiency（Fv/Fm） and photochemical quenching（qP） ,chlorophyll content in Zhongmai 1 was lower than that in Zhoumai 18 ;the increased degree of non-photochemical quenching （NPQ） , the content of proline and soluble protein in Zhongmai 1 was higher than that in Zhoumai 18. The net photosynthetic rate of Zhongmai 1 and Zhoumai 18 decreased by 36.47% and 30.91% after low temperature stress for 24 h,and decreased by 57.00% and 49.18% after 48 h. The tendency of superoxide dismutase,peroxidase and catalase activities rose first and fell later,the increase degree of Zhongmai 1 was higher than that of Zhoumai 18 ,while it showed the opposite tendency for the inhibition degree. The yield per plant decreased significantly,Zhoumai 18 and Zhongmai 1 decreased by 31.00% and 19.09% after low temperature stress for 24 h, and decreased by 56.85% and 46.59% after 48 h. The effective heads per plant and grains per head were seriously reduced by low temperature. Collectively,Zhongmai 1 can accumulate more proline and soluble protein, and maintain higher antioxidant enzyme activities than Zhoumai 18 under low temperature stress,which can relieve the damage to the leaves, keep in higher level of photosynthetic efficiency and get higher yield. This is the reason for its good tolerance to low temperature.