干旱和复水对东北红豆杉叶片叶绿素荧光特性和抗氧化酶活性的影响

Effects of Drought Stress and Rehydration on Chlorophyll Fluorescence Characteristics and Antioxidant Enzyme Activities in Leaves of Taxus cuspidata

以东北红豆杉(Taxus cuspidata)3a生实生苗和扦插苗为实验材料,研究干旱和复水后实生苗和扦插苗的叶绿素荧光和抗氧化酶活性变化规律,为更好地培育东北红豆杉资源提供理论依据。研究结果表明,实生苗对于干旱适应性强于扦插苗。在干旱处理过程中,随着干旱条件加剧,实生苗和扦插苗初始荧光Fo和非光化学猝灭系数NPQ均表现出升高趋势,扦插苗Fo升幅较快,而实生苗NPQ升幅较大。与实生苗相比,扦插苗的PSⅡ最大量子效率(Fv/Fm),PSⅡ实际光化学量子效率(ФPSⅡ)和光合电子传递速率(ETR)表现出较大幅度的降低,说明扦插苗对干旱胁迫较敏感。但复水后,实生苗和3a生扦插苗荧光参数均恢复到正常水平。干旱胁迫条件下,实生苗和扦插苗抗氧化酶SOD、CAT和POD均表现出升高。

Three-year-old Taxus cuspidata seed seedling and cutting seedling were selected as the experimental material.The aims of this study were to explore the response and ecological adaptability of Taxus cuspidata seed seedling and cutting seedling to drought stress by investigating change of chlorophyll fluorescence characteristics and antioxidant enzyme activities.Result showed that minimum chlorophyll florescence（Fo） and non-photochemical quenching（NPQ） increased under the course of natural drought,Fo in cutting seedling increased faster than in seed seedling,and NPQ in seed seedling increased faster than in cutting seedling.After 15 days of drought stress,the cutting seedling showed significant decrease in maximum quantum efficiency of photosystemⅡphotochemistry（Fv/Fm）,effective PSⅡquantum yield（ФPSⅡ） and apparent electron transport rate（ETR）,compared with seed seedling.However,the alterations of seed seedling and cutting seedling could recover after rehydration.Under the drought stress,antioxidant enzyme activities of SOD,CAT and POD of seed seedling and cutting seedling increased.This indicated that the seed seedling had more drought adaptability than cutting seedling.