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本文研究了土壤干旱对小麦叶片渗透调节和光合作用的影响.小麦叶片水势、相对含水量、饱和渗透势、光合速率、蒸腾速率和气孔导度随土壤干旱程度加剧呈现出先缓降后陡降的趋势,其变化的土壤相对含水量阈值相同.小麦旗叶的渗透调节能力约为0.5MPa,不同叶位叶片渗透调节能力不同,其强弱顺序为旗叶>倒二叶>倒三叶.干旱使叶片膨压丧失时的渗透势从正常水分处理的-1.61MPa降到-2.33MPa,弹性模量从5.74MPa增加到6.35MPa.干旱条件下的光合速率、气孔导度、气孔限制值和叶片光合放氧能力都下降,而细胞间隙CO_2含量增加,说明光合速率的降低是非气孔因素即叶肉细胞光合活性限制的结果.
In this paper, the effects of soil drought on osmotic adjustment and photosynthesis of wheat leaves were studied.The water potential, relative water content, saturated osmotic potential, photosynthetic rate, transpiration rate and stomatal conductance of wheat leaves increased slowly and then dropped sharply The change threshold of soil relative water content is the same.The osmotic adjustment ability of wheat flag leaf is about 0.5MPa, the ability of osmotic adjustment of different leaf position leaves is different, the order of its strength and weakness is flag leaf> inverted leaf> inverted leaf. The osmotic potential at the time of loss of turgor pressure decreased from -1.61MPa to -2.33MPa and the modulus of elasticity increased from 5.74MPa to 6.35MPa at normal moisture treatment.Photosynthetic rate, stomatal conductance, stomatal limitation, Photosynthetic oxygen release capacity decreased, while the intercellular CO 2 content increased, indicating that the reduction of photosynthetic rate is non-stomatal factors that mesophyll cell photosynthetic activity results.