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杉木(Cunninghamia lanceolata)是中国南方最重要的人工林树种,但是它对干旱的高度敏感性限制了其发展,因此了解杉木对干旱的种内变异可以帮助我们更好地进行经营管理.本文分别选择来源于低降水量(LP)、中降水量(MP)和高降水量(HP)生境的3年生杉木幼苗,在干旱胁迫下(20％的土壤体积含水量)生长40天,开展不同种源杉木对干旱胁迫的生理生态响应和适应策略的研究.研究结果表明,杉木具有应对干旱的种源特异性适应策略.LP种源对干旱胁迫具有最好的耐受性,表现为作为渗透保护物质的碳水化合物和含氮化合物的大量积累,这是由快速的碳、氮代谢驱动的.同时,最高的POD活性可以有效消除干旱胁迫下LP种源中过量的H2O2.MP种源储存了大量的非结构性碳水化合物,这些碳水化合物可能在干旱胁迫时起到一定的缓冲作用.特别是,当遇到缺水时,其可以及时有效地关闭气孔以减少蒸腾作用,有助于适应长期的干旱.因此,MP种源采取了保守的节水策略.然而,HP种源可通过调节根系生长(增加R/S)并降低水势帮助其吸收水分.这种种源间的不同策略可能与地理环境的长期驯化有关.因此,我们的研究结果强调了植物对干旱胁迫种源特异性响应的重要性,对今后加快抗旱种质的选择和培育高产人工林具有重要意义.“,”Aims Cunninghamia lanceolata is one of the most important coniferous species in southern China,but its high sensitivity to drought restricts its expansion.Understanding the intraspecific variation of physiological responses to drought can help us manage this plantation better.Methods We selected 3-year-old seedlings of C.lanceolata,which originated from the low precipitation (LP),middle precipitation (MP) and high precipitation (HP) habitats,respectively.Seedlings were grown under drought stress (20％ of soil volumetric water content) for 40 days.The ecophysiological responses and adaptive strategies with different drought tolerance were investigated.Important Findings LP provenance possessed the best tolerance to drought stress,suggesting that considerably increased carbohydrates and nitrogen-containing compounds as osmotic protective materials,which were driven by fast carbon and nitrogen metabolisms.In addition,the highest peroxidase activity could effectively eliminate hydrogen peroxide in drought-stressed LP provenance.The MP provenance reserved a large amount of non-structural carbohydrates,which may act as a certain buffer for encountering drought stress.Importantly,timely closure of stomata to reduce needle transpiration when encountering a water deficiency would help them adapt to long-term drought.MP provenance adopted a conservative water-saving strategy.However,HP provenance regulated root growth (increased root/shoot ratio) and reduced penetration potential to help them absorb water.The different strategies among provenances may be related to the long-term domestication of the geographical environments.Therefore,our results underline the importance of provenance-specific responses to drought stress.It is highly significant to accelerate the selection of drought-resistant germplasms and to cultivate high-yield plantations in the future.