多枝柽柳气体交换特性研究  

Studies on gas exchange of Tamarix ramosissima Lbd.

作　　者：邓雄[1] 李小明[1] 张希明[1] 叶万辉[2] Andrea Foezki Michael Runge 

机构地区：[1]中国科学院华南植物研究所,广州510650 [2]中国科学院新疆生态与地理研究所,乌鲁木齐830011 [3]Institute of Ecology and Ecosystem

出　　处：《生态学报》2003年第1期180-187,共8页Acta Ecologica Sinica

基　　金：国家重点基础研究与发展资助项目 ( G1 9990 4 35 0 5 0 4 );中欧政府间科技合作资助项目 ( INCO-DC972 774 );国家自然科学基金资助项目 ( 39870 1 5 4 );中国科学院资源与生态环境研究重大资助项目 ( KZ95 1 -B1 -2 31 )~~

摘　　要：在美国柽柳 ( Tamarix L.)被列为臭名昭著的十大外来杂草之一 ,而在中国 ,它则作为一种濒危物种生存状况堪忧。对多枝柽柳 ( Tamarix ramosissima Lbd.)气体交换进行研究 ,探讨其蒸汽压差 ( VPD)、叶水势、气孔导度 ( gs)和水分利用效率 ( WUE)之间的联系 ,结果表明 ,柽柳之所以能在沙漠生存又能在美国河岸地带疯狂扩展 ,主要原因可能是 :1柽柳属地下水湿生植物 ,发达的根系能直达地下水。 2柽柳适应性生境很广 ,作为一种阳性树种 ,柽柳非常耐旱 ,能够在很低的叶水势 (ψ)条件下 ( - 4.5 9MPa)进行光合作用 ,而较低的光补偿点和暗呼吸速率又反映出其耐阴湿的特点。 3灵敏的气孔适应性调整 :其 gs对 VPD的灵敏性随着干湿季其体内的水分状况变化而变化 ,调整蒸腾速率 ,从而影响其 WUE;gs与 ψ成显著正相关 ( P≤ 0 .0 5 ) ;gs与 WUE显著相关 ( P≤ 0 .0 5 ) ,但只有当 gs处于正在下降的时候 ,光合作用和蒸腾作用两个交换过程受轻微限制时 ,可得到水消耗和 CO2 吸收的最优协调 ,WUE达到最大值。这些适应性调整可能是柽柳能在美国河岸地带疯狂扩展的主要原因。实验结果表明 ,柽柳完全能够适应荒漠生长环境 ,因而导致柽柳在我国处于濒危状况的根本原因不是传统认为的干旱的自然环境 ,而主要是人为因素造成地?Tamarix Lbd, common name Saltcedar, one of the ten worst noxious invading weeds in USA, is classified as an endangered plant in China. We studied the gas exchange of T.ramosissima, and analysed the relationships among its leaf water potential (ψ), stomatal conductance (g s),vapor pressure deficit(VPD) and water use efficiency(WUE). The results showed, the reasons that saltcedar can both exist in the desert and spread rampantly in the riparian area in America may be:①Saltcedar is a phreatophyte, whose roots can reach the deep groundwater.②It has a good adaptability to different niches. Saltcedar is a heliophyte plant with good drought resistance, able to perform gas exchange at very lowψ(-4.59MPa).We inferred that it can adapt itself to wet and shade environments from its low light compensation point(LCP) and dark respiration(R d).Also it is salt-tolerant. ③It has a sensitive regulation of stomatal. Gs had a significant negative correlation(P≤0.05) with from leaf to air VPD. The sensitivity of g s to VPD varied with the water condition of the leaves in dry or wet seasons, and regulated its transpiration, which affected WUE. G s had a significant positive correlation withψ, and was significantly related to WUE(P≤0.05), When g s was about to decline, maximum WUE occurred and photosynthesis and transpiration were being limited slightly by VPD. All these adaptive regulations probably help to explain the rampant spread of saltcedar in the riparian region in America. Traditionally, people have thought the dry natural conditions are the ultimate reason that endanger the existance of saltcedar in the desert, while our results suggest the main reason are artificial factors including over-us of water causing a lowing of groundwater and excessive harvest.

关 键 词：多枝柽柳 气体交换特性 水势 气孔导度 水分利用效率 地下水湿生植物 

分 类 号：Q945.1[生物学—植物学]