温度和光照强度对不同品质类型小麦旗叶光合特性和衰老的影响

以两个蛋白质含量不同的小麦品种豫麦34（高蛋白）和扬麦9号（低蛋白）为材料，研究不同温光条件对小麦灌浆期旗叶光合特性和衰老的影响.结果表明：高温、弱光处理显著降低了小麦旗叶净光合速率（P_n）及叶绿素荧光参数F_v/F_m和Φ_PSⅡ，但高温和弱光对小麦旗叶造成伤害的生理机制不同，高温主要降低了叶绿素含量(SPAD值)和P_n，灌浆后期P_n下降幅度达50％;而弱光主要降低了叶绿素荧光参数，抑制了光合系统PSⅡ的活性.高温使小麦旗叶丙二醛（MDA）含量升高，超氧化物歧化酶（SOD）活性和可溶性蛋白质含量下降，加速了植株衰老；而弱光下SOD活性较高，小麦衰老进程较高温缓慢，植株对弱光的耐受性较强.豫麦34对高温、弱光逆境的反应比扬麦9号敏感.

Effects of temperature and illumination on flag leaf photosynthetic characteristics and senescence of wheat cultivars with different grain quality.

Taking wheat cultivars Yumai 34 (high protein content in grain) and Yangmai 9 (low protein content in grain) as test materials, and by the method of growth chamber, this paper studied the effects of different combinations of temperature and illumination on the photosynthetic characteristics and senescence of their flag leaves at grain-filling stage. The results showed that both high temperature and low illumination had negative effects on the photosynthesis. They decreased the net photosynthetic rate (Pn), photochemical efficiency (Fv/Fm), and actual photochemical efficiency (PhiPSII) significantly, but their action mechanisms were differed. High temperature mainly decreased the chlorophyll content (SPAD value) and Pn, while low illumination mainly decreased the chlorophyll fluorescence parameters Fv,/Fm and PhiPSII, and thus, inhibited the activity of PS II. High temperature increased the MDA content and decreased the soluble protein content and SOD activity, resulting in the acceleration of senescence, while low illumination increased the SOD activity and slowed down the senescence. Yumai 34 was more sensitive to high temperature and low illumination than Yangmai 9.