极端干旱区胡杨宽卵形叶水分变化影响因子分析

 以新疆塔里木河下游极端干旱环境下胡杨宽卵形叶为研究对象,结合对气象因子、土壤水盐和胡杨叶片气体交换、水势特性的实地监测资料,研究了影响胡杨叶片气体交换特性和水势变化的主导环境因子,揭示了反映胡杨生长发育期叶片水分变化的环境因子的指示性和指示阈值。结果表明,空气相对湿度、气温等气象因子是影响极端干旱区胡杨叶片水势和气体交换特性变化的主要因素；（48.19±1.06）%的空气相对湿度是影响胡杨叶片气体交换特性变化的临界阈值,可作为反映胡杨生长与否的指示指标,不能反映胡杨叶片水分变化状况。在极端干旱的塔里木河下游,空气相对湿度在10.69%~48.19%时利于胡杨叶片气体交换和生长。该研究可为减轻胡杨受旱程度、维持胡杨正常生长及时补充水分提供理论依据。

Analysis on the Factors Influencing Moisture Change in Broad-ovate Leaves of Populus euphratica Oliv.in Extremely Arid Region

The main object of this paper was to analyze the factors influencing moisture change in broad-ovate leaves of Populus euphratica Oliv.under the extremely arid environment distributed in the lower reaches of the Tarim River in Xinjiang,China.Measurements were conducted on gas exchange and water potential of P.euphratica leaf,climate factors and soil water and salt content.Results showed that:(1) the primary factors influencing moisture change in P.euphratica leaf in the extremely arid zone were climate factors,such as air relative humidity,air temperature,etc.;(2) air relative humidity of(48.19±1.06)% was a critical threshold value influencing the growth of P.euphratica leaf,but was not the indicating index reflecting the moisture state of P.euphratica.When relative humidity was from 10.69% to 48.19%,the gas exchange and growth of P.euphratica leaf were good in the lower reaches of Tarim River.This study will provide the theoretical basis on alleviating drought stress and maintaining the natural growth of Populus euphratica.