浮尘对冬小麦叶片光合作用及细胞膜透性的影响

我国是浮尘发生频繁的国家。浮尘作为一种灾害性天气不仅直接危害作物,而且通过减少直接辐射,减缓冰雪融化,减少河水流量,改变土壤性质等间接影响作物的生长发育。因此,深入研究浮尘对作物的影响具有重要意义。但目前,国内外的学者主要偏重研究人为粉尘和工业污染物对野生植物及绿化植物的影响,较少关注自然降尘对作物的影响;特别是在长期浮尘胁迫下冬小麦叶片的气孔导度、净光合速率、细胞质膜相对透性等生理指标的变化很少有研究。通过模拟降尘和盆栽试验,研究了拔节期和盛花期的降尘对冬小麦叶片温度（Tleaf）、叶绿素含量（Chl）、游离脯氨酸含量（Pro）、净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、细胞膜透性的影响（MP）。结果表明,降尘使拔节期和盛花期冬小麦的净光合速率分别下降52%和43.9%,差异均显著（P〈0.05）;降尘还增大细胞膜透性,破坏了冬小麦自身调节系统,使拔节期和盛花期的叶绿素含量分别下降14.4%和20.4%,达到极显著差异（P〈0.01）;降尘还使拔节期叶片的气孔导度下降到对照的26.9%（P〈0.05）,同时叶面温度升高,脯氨酸含量增加38.2%。

Effects of suspended dust on the photosynthesis and the membrane permeability of winter wheat leaves

Suspended dust, as a kind of catastrophic weather occurring frequently in China, not only results in direct damages on crops, but also produces indirect effects on growth of crops through decreasing direct radiation, reducing thaw of ice and snow, decreasing river water, and changing soil properties. Therefore, further studies on the effects of suspended dust on crops are of important theoretical and practical significance. At present, researchers in the world mainly studied the effects of the anthropogenic dust and industrial pollutants on wild vegetations and forestation plants, but paid little attention to influence of natural suspended dust on crops, especially neglected the studies on changes in stomatal conductance （Gs）, net photosynthesis （Pn）, intercellular CO2 concentrations （Ci）, membrane penetrability of winter wheat leaves under a long-time stress of suspended dust. Through pot experiments of winter wheat with simulated stress of suspended dust, this paper studied the effects of suspended dust on the temperatures （Tleaf）, chlorophyll contents （Chl）, the proline contents （Pro）, net photosynthesis （Pn）, stomatal conductance （Gs）, intercellular CO2 concentrations （Ci）, and membrane penetrability （MP） of winter wheat leaves in the jointing stage and flowering stage. The main results are as follows： In the jointing stage and flowering stage, the simulated suspended dust reduced significantly the net photosynthesis （Pn） in winter wheat leaves by 52% and 43.9% （P〈0.05）, respectively. Because of increasing the membrane penetrability （MP） and damaging the membrane protective system of winter wheat leaves, the simulated suspended dust decreased the chlorophyll contents （Chl） by 14.4% and 20.4%, respectively, showing an extremely significant relativity （P〈0.01）. Compared with the control in the jointing stage, the simulated suspended dust reduced the stomatal conductance （Gs） by 26.9% （P〈0.05）, enhanced the leaf temperature （Tleaf） and the proline contents （Pro） by 38.2% （P〈0.01） in winter wheat leaves.