3种华北石质山区造林树种抗旱性评价

Drought resistance evaluation of three afforestation tree species in lithoid hilly area of North China

为研究白蜡(Fraxinus chinensis)、麻栎(Quercus acutissima)、皂荚(Gleditsia sinensis)3种华北石质山区常用造林树种的抗旱性,采用盆栽控水的试验方法,测定2年生白蜡、麻栎、皂荚幼苗在持续干旱条件下的光合参数、丙二醛(MDA)、细胞膜透性、叶片相对含水量、叶绿素含量、超氧化物歧化酶(SOD)活性、脯氨酸一系列生理指标对干旱胁迫的响应。用灰色关联分析比较各生理指标与抗旱性的关系,用隶属函数法综合评价3树种的抗旱性。结果表明:随着干旱加剧,白蜡和皂荚在T3时限制其光合作用的因素从气孔限制转为非气孔限制;3树种的MDA、细胞膜透性和SOD都呈上升趋势,而叶片相对含水量和净光合速率呈下降趋势;麻栎叶绿素含量呈上升趋势,白蜡和皂荚则是先上升后下降;皂荚脯氨酸含量大幅上升,白蜡和麻栎的脯氨酸含量基本保持不变。用隶属函数法对3树种进行综合抗旱性排序,无论是中度还是重度干旱胁迫下3树种的抗旱性排序都表现为:麻栎>皂荚>白蜡;灰色关联分析表明:在中度干旱胁迫时叶片相对含水量、SOD活性与3树种的抗旱性关联较密切;在重度干旱胁迫时叶片相对含水量、细胞膜透性与抗旱性关联较密切。

[Background]The soil in the lithoid hilly area of North China is poor and the soil erosion is serious,which severely restricts the productivity of these undeveloped mountains.Vegetation restoration is an important measure in recovering ecological environment.A large number of studies have shown that when plants are subjected to drought stress,a series of physiological changes will be produced in plants to adapt to drought stress,but the response characteristics,adaptability and physiological mechanisms of different plants to drought stress vary.Therefore,studying the response characteristics and physiological mechanisms of different tree species under drought stress has important practical significance for its application in barren hills greening and vegetation restoration.[Methods]Using the test method of potted water control,102-year old plants and consistent Fraxinus chinensis,Quercus acutissima and Gleditsia sinensis seedlings were selected as test materials,and their photosynthesis parameters,MDA content,cell membrane permeability,relative water content,leaf chlorophyll content,SOD activity,and proline content in response to drought stress under continuous drought conditions were determined.The relationship between each physiological index and drought resistance was compared by grey relational analysis,the drought resistance of three tree species was comprehensively evaluated by membership function method.[Results]1)With the drought increasing,the MDA content,membrane permeability and SOD activity of three tree species increased,while the relative water content and net photosynthetic rate of leaves decreased,and the chlorophyll content of Q.acutissima increased.2)The proline content of the G.sinensis was greatly increased,and the proline content of the F.chinensis and Q.acutissima remained substantially unchanged.The drought resistance of three tree species under moderate or severe drought stress was ranked by membership function method,the results showed as G.sinensis>Q.acutissima>F.chinensis.3)Grey correlation analysis showed that the correlation between the indexes of moderate drought conditions and drought resistance was as follows:leaf relative water content(0.784)>SOD activity(0.723)>chlorophyll content(0.652)>cell membrane permeability(0.527)>MDA content(0.526)>net photosynthetic Rate(0.506)>proline content(0.503).The correlation between various indicators and drought resistance in severe drought conditions was as:leaf relative water content(0.749)>cell membrane permeability(0.632)>net photosynthetic rate(0.563)>SOD activity(0.543)>MDA content(0.528)>chlorophyll content(0.508)>proline content(0.506).[Conclusions]The three tree species have certain commonality in the means of resisting drought,that is,to prevent drought stress by maintaining the leaf water and SOD to eliminate free radicals and reducing the degree of lipid membrane peroxidation.This research can distinguish the differences between different physiological indicators in the drought stress of plants and screen the drought-resistant tree species to provide reference for the selection and ecological restoration of afforestation species in the lithoid hilly area of North China.