为了探索玉米穗发育对高温逆境的生理响应机制，以两个种质来源不同、耐热性差异较大的玉米品种郑单958(ZD958)和先玉335(XY335)为材料，从第9 片叶展开期至抽雄吐丝期，进行大田人工模拟增温处理。结果表明，高温胁迫下，玉米雄穗、雌穗的抗氧化生理在品种及处理间均具有较大差异，(1)雄穗细胞中超氧化物歧化酶(SOD)活性呈现升-降-升的变化，ZD958雄穗上部的小穗的SOD活性低于下部小穗，XY335雄穗上部小穗SOD活性高于下部小穗；过氧化物酶(POD)活性在高温处理初期下降，而后持续升高，XY335升高的幅度大于ZD958；过氧化氢酶(CAT)活性在高温胁迫初期增加，而后下降甚至低于对照；丙二醛(MAD)含量均呈现增加趋势，ZD958雄穗细胞中MAD的含量较低，增加的幅度也较小；ZD958雄穗中可溶性糖和脯氨酸含量较高，XY335雄穗中可溶性蛋白含量较高。(2) XY335雌穗的SOD、POD和CAT酶活性降低或显著降低，MDA含量较高；ZD958雌穗的SOD、POD和CAT酶活性升高或显著升高，MDA含量较低；随着高温胁迫的持续，ZD958和XY335雌穗中可溶性糖、可溶性蛋白和脯氨酸含量均呈增加趋势，耐热性较强的ZD958雌穗具有较高的可溶性糖含量、较高的花丝水势和pH值。
英文摘要:
In order to explore physiological mechanism of response of maize reproductive organs to high temperature stress during the reproductive stage, a field experiment of artificial warming from the V9 stage to VT was conducted with two maize varieties Zhengdan 958 (ZD958) and Xianyu 335 (XY335) differing in germplasm sources and heat tolerant. The results showed that there were significant effects of high temperature treatments during the reproduction organs developmental stage on antioxidant enzyme activities of summer maize. Under the high temperature, the antioxidant system activities of maize reproductive organs were differences among maize varieties and treatments. (1) The superoxide dismutase(SOD) activity in tassel of maize showed a change of increasing- decreasing- increasing. The SOD activity was lower in top spikelet than in basal spikelet of ZD958 tassel, while the SOD activity was higher in top spikelet than in basal spikelet of XY335 tassel. The peroxidase (POD) activity decreased in early, then increasing, and the increasing extent was higher in XY335 tassel than in ZD958 tassel. The catalase(CAT) activity increasd in early, then decreasing and even lower than control. The malondial dehyde (MDA) contents had a increasing trend in two maize activities tassel, but the MDA content and its increasing extent were lower in ZD958 tassel than in XY335 tassel. Compared with heat sensitive variety XY335, higher contents of soluble sugar and proline were found in tassel of heat tolerant variety ZD958. (2) The antioxidant enzyme activities of SOD , POD and CAT were decreased or decreased significantly and had a higher MDA content in ear of heat sensitive variety XY335, but the antioxidant enzyme activities were increased or increased significantly and had lower MDA content in ear of heat tolerant variety ZD958. As high temperature stress, the contents of soluble sugar, soluble protein and proline all increased in ear of ZD958 and XY335. Compared with XY335, ZD958 had a higher sugar content, a lower contents of soluble protein and proline,in ear, and a higher water potential and pH value in ear silk.
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