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摘要：近年来，随着全球气候变化，高温灾害频发，已成为限制我国棉花生产的重要环境因子之一。研究高温对棉花光合能力的影响对于选育耐高温品种、提升高温抗逆栽培技术意义重大。本试验于20XX年，在江苏南京(118º50′E, 32º02′N, 长江流域下游棉区)进行盆栽试验，以高温敏感型品种苏棉15和高温弱敏感型品种PHY370WR为材料，在自动控温室内对棉株进行5天的高温处理，研究高温对棉铃对位叶光合能力的影响。结果显示，高温处理5天后，相比于对照条件，两个棉花品种的叶片中胞间CO2浓度、蒸腾速率、淀粉含量和比叶重都上升，且苏棉15的上升幅度都大于PHY370WR；而叶片的气孔导度、净光合速率、叶绿素含量、叶绿素a/b值、蔗糖含量、最大光化学量子产量(Fv/Fm)、实际光化学量子产量(ΦPSII)、Rubisco初始活性、Rubisco活化率、磷酸蔗糖合成酶（SPS）活性和蔗糖合成酶（SuSy）活性都下降，且苏棉15的的下降幅度显著大于PHY370WR。上述结果表明:（1）高温条件下，棉花净光合速率下降由非气孔限制所引起,叶绿素含量、ΦPSII、Fv/Fm下降是光合速率下降的重要原因。同时,高温导致了叶片中Rubisco、SPS、SuSy活性下降，使蔗糖合成减少，光合产物以淀粉形式在叶片中累积，导致比叶重增加，光合产物输出减少。（2）不同基因型陆地棉对高温的敏感性存在差异，耐高温品种在高温下叶绿素含量、ΦPSII、Fv/Fm下降幅度较小，从而保持较高的光合能力。同时,较高的Rubisco、SPS、SuSy活性使其蔗糖合成能力较强，光合产物输出多，而向淀粉方向累积少，因此比叶重上升幅度小。29466
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毕业论文关键词：高温；棉花；棉铃对位叶；光合能力
Effects of high temperature on photosynthetic capacity of the subtending leaf of cotton
Abstract： In recent years, with the global climate changing, the disasters caused by high temperature occurred frequently, which has become one of the most important environmental factors limiting the production of cotton in China. To understand the effect of high temperature on cotton and its mechanism would have great significance for the breeding of high temperature resistant varieties and the improvement of high temperature and anti stress cultivation techniques. The experiment was carried out in pot in 2016, using cotton cultivars Simian 15 and PHY370WR, in Pailou experiment station of Nanjing Agricultural University (118º50′E, 32º02′N). By making high temperature treatment on the cotton for 5 days in automatic temperature control room，the aim was to study the effect of high temperature on the photosynthetic capacity of the subtending leaf of cotton boll which is the main functional leaf during the development of cotton bolls. The results indicated that, 5 days after high temperature treatment, compared to the control condition, the intercellular CO2 concentration、transpiration rate、starch content and specific leaf weight all increase. Also, the increase of Simian 15 is greater than PHY370WR. The stomatal conductance to water vapor、net CO2 assimilation rate、chlorophyll content、chlorophyll a/b、sucrose content、maximal photochemical quantum yield、actual photochemical quantum yield、rubisco initial activity、rubisco activation rate、SPS activity and SuSy activity all reduce. The decline of Simian 15 is significantly greater than PHY370WR. These results indicate that: (1) Under high temperature condition, the decrease of net photosynthetic rate was not caused by stomatal limitation, but the decrease of chlorophyll content, PSII and Fv/Fm were the main reasons. Meanwhile, high temperature resulted in the decrease of Rubisco,SPS and SuSy activity, which reduced the synthesis of sucrose. The photosynthate accumulates in leaves in the form of starch, which resulted the specific leaf weight increased and the photosynthetic product output decreased. (2) The sensitivity of different genotypes of upland cotton to high temperature is different. The content of chlorophyll, PSII, Fv/Fm decreased with a smaller decline in high temperature resistant varieties under high temperature, to maintain a higher photosynthetic capacity. At the same time, the higher Rubisco, SPS and SuSy activity makes its sucrose synthesis ability stronger, the photosynthetic product output more, but less starch accumulation. Therefore, the increase of specific leaf weight is small.