草原地区不同生态类型的植物生理特性的比较研究

Comparison of physiological characteristics of different ecotype plants.

比较研究了4种不同水分生态型植物在不同水分胁迫下的光合作用、叶片含水量和气孔阻力等生理指标的反应.结果表明,不同水分生态型植物抵御干旱的机制是不同的.中生植物主要是通过增加气孔阻力限制蒸腾失水,而旱生植物则依靠高浓度的细胞原生质减少水分的散失,后者保水效率远高于前者.植物从中生种到旱生种,生理特性亦显示出规律性的种间差异,叶片含水量和气孔阻力水平降低,而单位叶面积的净光合速率增加.

Studies on the responses of photosynthesis,leaf water content and stoma resistance of 4 different ecotype plants to water stresses showed that their mechanism of drought resistance was different.Mesic plants limited water loss from transpiration by increasing their stoma resistance,while xeric plants decreased water loss by keeping the high concentration of cell protoplasm.The latter had a higher efficiency of keeping water than the former.The leaf water content and stoma resistance was decreased from mesic to xeric plants,while the net photosynthetic rate per unit leaf was increased, indicating the difference of physiological characteristics among different ecotype plants.