沙地生境和平茬年限对沙柳叶功能特征的影响  

Effects of sandy land water habitat and years after rejuvenation pruning on leaf functional traits of Salix psammophila

作　　者：张萍萍[1,2] 李秧秧[2,3] 邵明安[2,3] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [3]西北农林科技大学水土保持研究所,陕西杨凌712100

出　　处：《应用生态学报》2011年第9期2240-2246,共7页Chinese Journal of Applied Ecology

基　　金：国家林业局公益性行业科研专项(200904056);中国科学院创新团队国际合作伙伴计划项目资助

摘　　要：研究了毛乌素沙地南缘水滨边丘间地和干旱丘顶两种生境下沙柳平茬后不同年限(1、2、3～4和5～6年)对沙柳叶片光合气体交换、水分利用效率、结构特性及氮、磷养分含量等叶功能特征的影响.结果表明:水滨边丘间地沙柳叶片的净光合速率、气孔导度、瞬时和长期水分利用效率均高于丘顶,但N、P养分含量低于丘顶;两种生境下沙柳的叶结构性状无显著差异.干旱生境下沙柳主要通过增加养分含量、降低光合和水分利用来生存.随平茬年限增加,叶片净光合速率和气孔导度显著下降,氮含量和瞬时水分利用效率亦呈下降趋势,且二者之间呈显著正相关;平茬后1年的叶面积最高,比叶质量和叶干物质含量最低,此后比叶质量增加,叶面积和干物质含量不变;叶结构性状与光合及养分特性之间无显著相关性.叶光合活性和氮含量的下降是沙柳随平茬年限增加而衰败的重要原因.This paper studied the effects of habitats （riparian inter-dune and dry top dune） and years after rejuvenation pruning （1, 2, 3-4, and 5-6 years） on the leaf functional traits （gas exchange, water use efficiency, structural traits, and N and P contents） of Salix psammophila growing in the southern edge of Mu Us Sandy Land. In the habitat of riparian inter-dune, the leaf net photosynthetic rate, stomatal conductance, and instantaneous and long-term water use efficiencies were all higher, while the leaf N and P contents were lower, as compared with those in the habitat of dry top dune. No significant differences were observed in the leaf structural traits between the two habitats, suggesting that S. psammophila could survive in a dry habitat by the strategies of increasing nutrient uptake and decreasing photosynthesis and water use. With the increasing years after rejuvenation pruning, the leaf net photosynthetic rate and stomatal conductance decreased significantly, and the leaf N content and instantaneous water use efficiency also showed a decreasing trend, with a positive correlation between them. One-year after rejuvenation pruning, the leaf area was the highest, and the specific leaf mass and leaf dry matter content were the lowest. Thereafter, the leaf area and dry matter content had no obvious change, but the specific leaf mass increased with increasing years after rejuvenation pruning. There were no significant correlations between leaf structural traits and photosynthetic and nutrient traits, suggesting that the decreases of leaf photosynthetic capacity and N content were the major reasons for S. psammophila senescence with increasing years after rejuvenation pruning.

关 键 词：沙柳 水分生境 平茬年限 叶功能性状 

分 类 号：S793.9[农业科学—林木遗传育种]