土壤水分含量对天目琼花生理特性的影响

为探讨干旱胁迫下天目琼花的光合机构功能及其干旱逆境的生理响应机制,采用室外盆栽的试验方法,研究了天目琼花在不同土壤水分条件下的生理生态反应。结果表明:随着土壤含水量的减少,天目琼花的蒸腾速率日进程曲线由双峰变成单峰,净光合速率、Fv/Fm日进程曲线由低谷变成深谷,电子传递效率大幅降低,PSⅡ反应中心关闭。在供水处理Ⅱ的土壤水分条件下,叶片Car含量有所升高,热耗散能力明显增强,说明天目琼花能够对干旱胁迫做出积极响应;而在供水处理Ⅲ的土壤水分条件下叶片气孔关闭,Car含量大幅下降,热耗散能力达到饱和,不能对对干旱胁迫做出积极响应,说明叶片的光合机构可能受到了一定程度的光损伤。

Effect of the Soil Water Content on the Physiological Characteristics of Viburnum sargentii

In order to survey the photosynthetic function and physiological response mechanism of Viburnum sargentii under drought stress,the experiment in the simulation of soil drought was conducted and its physiological ecology response under different soil water levels were studied.The results showed that peak feature of diurnal change of transpiration rate was changed from double to single with soil water decreasing.Valley feature of diurnal change of net photosynthesis rate was changed from low to deep.ETR was descended obviously and reaction center of PSⅡ was closed.The content of carotenoid slightly was increased and the ability of thermal dissipation significantly was enhanced under the condition of water treatment Ⅱ.Stomata was closed,while the content of carotenoid was obviously descended and the ability of thermal dissipation slightly was increased under the condition of water treatment Ⅲ.Viburnum sargentii responsed actively under media drought but did not under severe drought.