灌浆初期高温影响水稻籽粒充实和剑叶理化特性_毕业论文（设计）.docVIP

灌浆初期高温影响水稻籽粒充实和剑叶理化特性 摘要：为探明灌浆初期高温热害降低水稻籽粒充实度的可能生理原因，本文以遗传背景相近而灌浆期耐热性存在显著差异的2个水稻纯系XN0437T（耐热）和XN0437S（热敏感）为材料，于水稻抽穗后第10天进行高温处理，调查了水稻籽粒充实度，测定了与水稻剑叶光合效率、细胞膜透性和渗透调节有关的生理指标。结果表明，高温处理后水稻籽粒充实度、叶绿素含量、剑叶的净光合速率和可溶性糖含量降低，热敏感纯系的下降幅度大于耐热纯系；超氧化物歧化酶（SOD）活性、细胞膜透性、丙二醛（MDA）和脯氨酸（Pro）含量增加，其中热敏感纯系的MDA含量、细胞膜透性增加幅度大于耐热纯系，而其SOD活性、脯氨酸含量的增加幅度小于耐热纯系。灌浆初期高温抑制水稻剑叶光合效率，增加细胞膜透性和改变细胞内环境是高温热害降低水稻籽粒充实度的生理原因。 关键词:水稻;高温;籽粒充实度;理化特性 Effects of high temperature on rice grain-filling of caryopsis and physiological biochemical characteristic of flag leave at early milky stage of rice The aim of this experiment was to ascertain possible physiological causes of high temperature decreasing grain-filling rate at early milky stage of rice. Two rice inbred lines, named XN0437T (heat-sensitive) and XN0437S (heat-tolerant), were selected and treated by high temperature at the 10th day after heading. The grain plumpness rate, indexes related to photosynthetic efficiency, cell membrane permeability and osmotic adjustment in flag leaves were detected in rice lines XN0437T and XN0437S. The result showed that the grain plumpness rate was reduced under high temperature in both XN0437T and XN0437S and the reduced range of heat-sensitive line was greater than that of heat-tolerant line. The net photosynthetic rate, chlorophyll content and soluble sugar content were decreased in comparison with control both in heat-sensitive and heat-tolerant rice lines, and the decrease range of these physiological matter contents were greater in the heat-sensitive line than that of the heat-tolerant line. The superoxide dismutase (SOD) activity, malonaldehyde (MDA) content, cell membrane permeability and proline (Pro) content were increased under high temperature, and the increased range of MDA content and membrane permeability in heat-sensitive line were higher than that in heat-tolerant line, while the increased range of SOD activity, Pro content in heat-sensitive line was less than that in heat-tolerant line. The present study sugges