4种高山杜鹃容器苗对持续干旱胁迫和复水的生理响应研究

Physiological response of four azalea seedlings after drought stress and rewatering

为评价高山杜鹃品种的耐旱性及对干旱胁迫的生理响应,以乡土树种云锦杜鹃为参照,系统测定了莱姆、弗吉尼亚、惠特尼3个常绿高山杜鹃品种在持续干旱胁迫和复水条件下的光合参数、叶绿素荧光参数、渗透调节物质等生理生化指标。结果表明,随干旱胁迫加剧,4种高山杜鹃的光合参数、叶绿素荧光参数均呈下降趋势;4种高山杜鹃的叶片水势均呈下降趋势,云锦杜鹃叶片水势下降幅度最小;4种高山杜鹃的相对电导率、渗透调节物质含量及H2O2含量均有所增加,在严重干旱时达到最大值。重度干旱下弗吉尼亚受到不可逆转的损伤,复水10 d后,除弗吉尼亚全部枯死无法恢复外,云锦杜鹃、莱姆和惠特尼的各项指标均恢复并接近对照水平。经主成分分析,将14个生理生化指标简化为累计贡献率为88.67%的2个综合指标,综合评价得到耐旱性排序为云锦杜鹃>莱姆>惠特尼>弗吉尼亚。

To evaluate the drought tolerance of alpine azalea varieties and their physiological responses to drought stress,with the native tree species Rhododendron fortunei as a reference,the photosynthetic parameters,chlorophyll fluorescence parameters,and osmotic adjustment of three evergreen alpine Rhododendron varieties,including‘Halfdem lem’,‘Virginia Richards’and‘Ann Rose Whitney’,were systematically determined.The results showed that the photosynthetic and chlorophyll fluorescence parameters of all four alpine azalea tested tended to decrease as drought stress intensified;the leaf water potential of four alpine azalea tended to decrease,with the smallest decrease in leaf water potential of R.fortunei;The relative conductivity and osmotic adjustment substance content of four alpine azalea increased,reaching a maximum during severe drought.Except for‘Virginia Richards’,irreversibly damaged,which could not recover,all indicators of the other three recovered and were close to control levels after ten days of re-watering.After Principal Component Analysis,the 14 physiological and biochemical indicators were simplified into 2 comprehensive indicators with a cumulative contribution rate of 88.67%.Their drought tolerance was presented by comprehensive evaluation in order as R.fortunei>‘Halfdem lem’>‘Ann Rose Whitney’>‘Virginia Richards’.