干旱胁迫下中红杨光合特性对环境因子的响应

Response of Photosynthetic Characteristics to Environmental Factors forPopulus×euramericana ‘Zhonghong’Under Drought Stress

为研究干旱胁迫下影响中红杨(Populus×euramericana‘Zhonghong’)光合特性的首要环境因子,试验采用盆栽控水法设置了3个干旱胁迫程度:CK(土壤相对含水量75%~80%)、MS(40%~45%)、SS(25%~30%)。结果表明:MS引起净光合速率(P_(n))和气孔导度(G_(s))下降,蒸腾速率(T_(r))升高,光合有效辐射(PAR)与P_(n)显著相关(P<0.01),P_(n)明显受PAR的影响,气孔限制成为P_(n)下降的主导因素;SS下,T_(r)、G_(s)和胞间CO_(2)浓度(C_(i))升高,大气温度(T_(air))与T_(r)显著相关(P<0.01),T_(air)是影响T_(r)的重要驱动因子,非气孔限制引起P_(n)下降。中红杨表现出较弱的光合抗旱性和高蒸腾特性。

In order to study the primary environmental factors affecting the photosynthetic characteristics of Populus×euramericana‘Zhonghong’under drought stress,the experiment took potting water control method with three degrees of drought stress:CK(relative water content of soil 75%~80%),MS(40%~45%)and SS(25%~30%).The results showed that under MS the net photosynthetic rate(P_(n)),stomatal conductance(Gs)decreased and transpiration rate(Tr)increased.Photosynthetic effective radiation(PAR)was significantly correlated with P n,which reflects that P_(n) was obviously affected by PAR,and the stomatal limitation became the main factor of P_(n) decrease.Under SS,Tr,G_(s),intercellular CO_(2) concentration(C_(i))increased;atmospheric temperature(T air)was significantly correlated with Tr.T air was an important driving factor affecting Tr.and it is non-stomatal limitationthat causes P n decrease.Populus×euramericana‘Zhonghong’had high transpiration characteristics and weak photosynthetic drought resistance.