【作者】 李敏；

【导师】 马均；

【作者基本信息】 四川农业大学 ， 作物栽培学与耕作学， 2008， 硕士

【摘要】 在高温、大田对照两种条件下用不同品种分别对水稻开花期、灌浆期和全生育期的生长发育和生理生化等性状特征进行了系统研究和分析,初步建立了水稻开花期和灌浆期的耐热性鉴定指标,深入研究了高温胁迫对水稻生理、生化、产量等指标的影响,充分论证了高温胁迫下水稻生理生化特性与品种耐热性的关系,揭示了决定水稻耐热性的关健生理生化机制。主要结果如下:1.水稻开花期高温胁迫降低了叶片光合速率、叶绿素含量,增加了可溶性糖、游离脯氨酸、MDA含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)的活性。通过相关分析表明,开花期高温胁迫与对照条件下的叶绿素、游离脯氨酸、MDA含量和SOD活性的变化幅度与品种的热敏感指数呈显著或极显著相关性,因此,高温下的叶绿素、游离脯氨酸、MDA含量和SOD活性的变化幅度可作为水稻开花期耐热性生理鉴定指标。对此4项指标变化幅度与热敏感指数进行逐步回归分析,所建立的回归方程可预测水稻开花期耐热性。2.灌浆期高温胁迫严重影响水稻的光合能力,酶保护机制和渗透调节能力。叶片光合速率,叶绿素、可溶性糖、蛋白质、MDA含量和SOD活性都是与水稻灌浆期耐热性密切相关的生理生化指标。但不同品种灌浆期耐热性存在相当大的差异。3.以水稻叶片光合速率,叶绿素、可溶性糖、蛋白质、MDA含量和SOD活性等与灌浆期耐热性密切相关性状的耐热指数为指标,应用主成分分析法将其综合成2个新的彼此独立的综合指标,再利用隶属函数值法求出每一品种耐热性的综合评价值,可较为全面、准确地评判各水稻品种的耐热性强弱。4.全生育期高温胁迫加速了水稻植株衰老和保护性功能的丧失,导致生育后期水稻叶片酶保护性机制失活,叶片渗透调节能力降低,干物质生产减少,茎鞘物质转运受阻,茎鞘物质输出率和转换率都显著下降,导致产量显著降低。在整个大环境升温情况下,应该注重生育中后期的田间管理。更多还原

【Abstract】 The experiment was carried out in growth chamber under both normal and high temperature to investigate the effects of heat stress on morphological, growth and development indexes and physiological and biochemical characteristics during flowering, grain filling stage and the whole growth stage. Identification index of heat resistance during flowering and grain filling stage had been established preliminary. The effects of heat stress on morphological, physiological, biochemical and grain yield had been carried out deep research. This paper adequately expounded and proved the relationship between physiological and biochemical characteristics and heat resistance in rice and discussed the key physiological and biochemical mechanism of heat resistance during grain flowering stage. The results followed:1. High temperature stress on flowering stage decreased leaves’ photosynthesis rate, contents of chlorophyll, increased contents of soluble sugar content, free proline content, malondialdehyde (MDA) content, as well as the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in leaves at flowering stage. Correlation analysis showed that heat susceptibility index significantly or very significantly correlated with relative changed percentage of contents of chlorophyll, free proline, MDA and SOD activity under both high temperature and normal conditions. Therefore, they could be selected as physiological identification indexes for heat tolerance at flowering stage in rice. Using stepwise regression equation to evaluate the heat tolerance of rice cultivars was considered scientifically and reliably.2. The ability of photosynthesis, osmotic adjustment and antioxidative enzyme activities were effected significantly in the high temperature condition at grain filling stage. The content of chlorophyll, soluble sugar, protein ,MDA, photosynthesis rate and the activity of SOD were correlated with heat resistance on grain filling stage. And heat tolerance on grain filling stage were different because of different cultivars.3. The content of chlorophyll, soluble sugar, protein, MDA, photosynthesis rate and the activity of SOD are correlative with heat tolerance at grain filling stage, which were synthesized to two new independent comprehensive indices by principal component analysis, Then the comprehensive evaluation of every rice varieties’ heat tolerance was obtained by subordinate function value method (SFVM), Consequently, each cultivar’ heat tolerance could be evaluated completely and correctly.4. The high temperature stress in the whole growth stage accelerated rice caducity and loss of protected functions, also lost the activities of antioxidative enzymes in leaves, decreased the osmotic adjustment of leaves, reduced the dry matters production, blocked the translocation and transformation of dry matters in stems and sheaths, decreased yields significantly. In the condition of higher environmental temperature, it should be important to strengthen the farming management in the late growth stage.更多还原