抽穗期高温对水稻叶片光合特性、叶绿素荧光特性和产量构成因素的影响

【目的】探讨抽穗期高温对水稻叶片光合特性、叶绿素荧光特性和产量构成因素的影响，为水稻生长发育过程中降低高温伤害提供理论依据。【方法】选用水稻品种盐两优1618和内5优8015为材料，利用人工气候箱，研究抽穗期不同温度［35 ℃/30 ℃（白天/夜晚）（T0，常温）和40 ℃/35 ℃（白天/夜晚）（T5，高温）］处理对水稻叶片光合特性、叶绿素荧光特性及产量构成因素的影响。【结果】与T0处理相比，高温处理（T5）分别使盐两优1618的净光合速率（P_n）和胞间CO₂浓度（C_i）显著下降31.05%和54.26%（P< 0.05，下同）；内5优8015的C_i显著下降62.61%，蒸腾速率（T_r）显著增加104.55%；其他光合参数未发生显著变化（P> 0.05，下同）；高温处理后，内5优8015的P_n显著高于盐两优1618。高温处理降低了盐两优1618和内5优8015各相位的荧光强度，延迟了2个品种的叶绿素荧光到达P峰的时间，同时降低了光化学效率、比活性和性能指数。高温处理显著降低了2个品种的实粒数和籽粒重，其中内5优8015的降低幅度较小。【结论】抽穗期高温在一定程度上能显著抑制水稻的光合参数，降低各相位的荧光强度，抑制光化学效率，并使水稻的穗重、实粒数和籽粒重下降。内5优8015的性能指数整体高于盐两优1618，其对高温的抗性强于盐两优1618。

Effects of high temperature on characteristics of photosynthesis and chlorophyll fluorescence and yield components of rice at heading stage

【Objective】In order to investigate the effects of hightemperature on photosynthetic characteristics, chlorophyll fluorescence characteristicsand yield components of rice at heading stage, and to provide theoretical basis for reducing high temperature damage to rice during rice growth and development.【Method】The effects of different temperature treatment 35℃/30℃(daytime/evening) (T0, ordinary temperature) and 40℃/35℃(daytime/evening) (T5, high temperature)] at heading stage on photosynthetic characteristics, chlorophyll fluorescence characteristics and yield components of rice cultivars Yanliangyou 1618(Y1618) and Nei 5 you 8015(N8015) were studied by using artificial climate chamber.【Result】Compared with T0 treatment, net photosynthetic rate(P_n) and intercellular CO₂ concentration(C_i) of Y1618 decreased significantly by 31.05% and 54.26%, respectively and C_i of N8015 was significantly reduced by 62.61% under T5 treatment, the transpiration rate was significantly increased by 104.55%(P< 0.05, the same below).Other photosynthetic parameters did not change significantly(P> 0.05, the same below).After high temperature treatment, P_n of N8015 was significantly higher than that of Y1618.The high temperature treatment reduced the fluorescence intensity of each phase of Y1618 and N8015, delayed the arrival time of chlorophyll fluorescence to P peak of the both cultivars, and reduced photochemical efficiency, specific activity and performance index.The high temperature treatment also decreased significantly grains number and weight, with lower degree of decrease for N8015.【Conclusion】To some extent, the high temperature at heading stage can significantly inhibit the photosynthetic parameters of rice, decrease the fluorescence intensity of each phase of rice, inhibit the photochemical efficiency and reduce panicle weight, solid grain number and grain weight of rice.The overall performance indexes of N8015 are higher than Y1618, indicating that N8015 is more resistant to high temperature than Y1618.