水分胁迫及复水对香蒲生长和光合参数的影响

Effects of Water Stress and Rewatering on Growth and Photosyntshetic Parameters of Typha Orientalis Presl

以香蒲为研究对象,通过盆栽试验,分析了其主要生长时期内在水分胁迫(水分处理由轻到严重分别为W1、W2、W3、W4以及对照CK)及复水条件下净光合速率(Pn)、气孔导度Gs、蒸腾速率Tr、水分利用效率(WUF)、株高PH、生物量等指标的变化特征。结果表明,以上指标随着水分胁迫程度加剧而降低;水分利用效率在7月底出现了较大差异,在试验结束时其大小为W2>W3>W1>CK,W4处理下水分利用效率不增反减,适度水分胁迫提高了水分利用效率;复水使受水分胁迫处理的香蒲生长和光合作用有所恢复,但都不能恢复到对照水平。W4处理恢复幅度最大,但由于其背景值最小,最好只能恢复到W3处理水平;30%的土壤含水量可能是香蒲受水分胁迫的阈值,当低于该值时复水后香蒲很难恢复到较好状态;复水后,由于香蒲增加了水分吸收使鲜重比干重增加更多。

The change of net photosynthetic rate （Pn）, stomatal conductance （Gs）, transpirationrate （Tr）, water use efficiency （WUE）, plant height （PH）, biomass of Typha orientalis Presl were analyzed by pot experiment under water stress and rewatering during growth period. Water stress was divided four levels as W1, W2, W3 and W4 from light to serious stress. In addition, check experiment （CK） was also conducted. The results showed that Pn, Gs, Tr, WUE, PH, biomass reduced with the increasing levels of water stress. WUE appeared large differences among stress treatment at the end of July. W2＞W3＞W1＞CK, while W4 level showed decreased instead of increased, so moderate water stress could increase WUE. Growth and photosynthesis of Typha orientalis Presl affected by water stress recovered after rewatering, but they could not recover to CK level. The extent of W4 recovering was larger among stress treatment; however its smallest background values only recover to W3 level as the best consequence. The threshold of water stress for Typha orientalis Presl may be 30% soil moisture; otherwise it would be difficult to recover to better conditions below the moisture after rewatering. Fresh weight of Typha orientalis Presl increased more than dry weight because of more water absorption after rewatering.