盐碱胁迫对青山杨光合特性的影响

青山杨(Poplars pseudo-cathayana×P.deltodides)是抗性良好的速生杂交杨,文章对其在盐碱胁迫下一个生长期内的光合生理特性进行了研究。结果表明,盐碱地和对照地上的青山杨在整个生长期内,净光合速率日变化都先后呈"双峰"、"单峰"和"平缓"型曲线。5～7月是青山杨全年光合作用最旺盛的时期,盐碱地青山杨日最大净光合速率为13.20μmol.m-2.s-1,对照地为14.53μmol.m-2.s-1,同比下降了9.15%。盐碱地和对照地蒸腾速率的日变化都呈"单峰"曲线,一年内5～7月蒸腾速率逐渐升高,7月15日达最大值后逐渐下降,在13:00左右蒸腾速率最大。盐碱地与对照地的气孔导度变化都呈双峰曲线,与光合速率变化相一致。盐碱地与对照地胞间CO2浓度与光合速率呈负相关。

Effect of saline-alkali stress on photosynthetic characteristics of Qingshan poplar

Qingshan poplar(Poplars pseudo-cathayana×P.Deltodides) was a poplar variety with salt resistance ability,its photosynthetic and correlated physiological characteristics were investigated in this study.The results showed that diurnal variation curves of net photosynthesis rate exhibited a bimodal peak,a unimodal peak and gentle pattern during the whole growing periods in saline-alkali stress soil and control condition.From May to July,Qingshan poplar had the largest net photosynthesis rate(13.20 μmol.m-2.s-1) in saline-alkali soil and control(14.53 μmol.m-2.s-1),and fell by 9.15%.The daily change of leaf transpiration rate was summarized as the single peak curve,which was increased from May to July,reached the peak at 13: 00 apparently on July 15th and began to decrease.In the saline-alkali and control soil changes of stomatal conductance also showed the double-peak curve and accordanced with the photosynthetic rate changes.Intercellular CO2 concentration and photosynthetic rate of the saline-alkali and control have a negative correlation.