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土壤类型是影响植物分布和生产力的重要环境因素,但有关土壤环境异质性对植物抗逆性效应的研究非常缺乏.本研究以美洲黑杨(Populus deltoids)为对象,以3种典型土壤类型(红壤、黄壤和黄棕壤)为栽培基质,在控制实验条件下,经过三个月的干旱胁迫(25％田间持水量)处理,测定了不同处理条件下美洲黑杨的气体交换速率、抗氧化能力、氮代谢特征、生物量积累与分配特征.研究结果表明,在红壤和黄壤条件下,与对照(75％田间持水量)相比,干旱胁迫显著降低了美洲黑杨各器官的生物量、光合速率、叶片氮同化酶的活性,显著增加了叶片中过氧化氢、丙二醛和无机氮的含量.在黄棕壤条件下,干旱对美洲黑杨总生物量、光合速率、氮同化酶以及质膜完整性的负面影响较小,这与其维持较高的超氧化物歧化酶,过氧化物酶和过氧化氢酶的活性相关,也与其生物量分配模式(如提高根冠比)密切相关.由此可见,生长在黄棕壤条件下的美洲黑杨表现出较强的抗旱能力,这可能与其土壤母质中较高的土壤养分和良好的通气状况相关.因此,就土壤类型而言,与红壤和黄壤相比,黄棕壤提供的土壤环境条件有利于美洲黑杨的抗逆表现和栽培利用.“,”Aims Although soil environments exist extensive heterogeneity for many plants with a wide range of distribution,researches about effects of soil conditions on plants'tolerance and adaptation are particularly inadequate.In our study,the aims are to reveal physiological strategies of Populus deltoides against drought stress under different soil conditions and to select the most suitable soil type for P.deltoides plantation.Methods Under controlled conditions,we used P.deltoides as a model species to detect differences in gas exchange rate,antioxidative capacity,nitrogen metabolism and biomass accumulation and partitioning in response to drought stress under three mineral soil types with distinct physicochemical characters,i.e.red soil(RS),yellow soil(YS)and yellow-brown soil(BS).Important Findings Exposure to 25％ of field ater holding capacity in soil for 3 months had significantly decreased biomass of all organs,photosynthetic rate,enzyme activities related to N assimilation,but increased H202,malondialdehyde and content of both N03-and NH4+,when P.deltoides was planted in both RS and YS.In contrast,under BS,there are slightly negative effects exerted by water deficit on total biomass,gas exchange rate,activities of enzymes related to nitrogen metabolism and membrane damage caused by reactive oxygen species,which can be associated with a consistent increase in superoxide dismutase,peroxidase and catalase,and a higher ratio of root mass to shoot mass.It is concluded that,such higher capacity in tolerance and adaptation against drought stress under BS relative to both RS and YS could be accounted for more sufficient nutrient pr vision in soil parental materials and better soil aeration conditions which play a vital role in plant acclimation to water shortage.Our study also revealed that,distribution areas of BS might be preferable for cultivation of P.deltoides,when compared with those of RS and YS.