CO_2浓度倍增条件下土壤干旱对两种沙生灌木碳氮含量及其适应性的影响  

Responses of two dominated desert shrubs to soil drought under doubled CO_2 condition

作　　者：许振柱[1] 周广胜[1] 肖春旺[1] 王玉辉[1] 

机构地区：[1]中国科学院植物研究所植被数量生态学重点实验室,北京100093

出　　处：《生态学报》2004年第10期2186-2191,共6页Acta Ecologica Sinica

基　　金：国家重点基础研究发展规划资助项目 ( G19990 43 40 7) ;中国科学院创新工程资助项目 ( KZCXI-SW-0 1-12 ;KSCX2 -1-0 7) ;国家自然科学基金资助项目 ( 4 0 2 3 10 18;3 0 0 70 64 2 ;3 0 0 2 80 0 1;4990 5 0 0 5 ;3 973 0 110 )~~

摘　　要：研究利用大型环境生长箱模拟了两种沙地优势灌木柠条和羊柴对 CO2 浓度倍增和土壤干旱交互作用的响应。 CO2 浓度倍增使柠条和羊柴的生物量分别增加了 6 2 .90 %和 5 0 .0 0 % ,使植株叶面积分别增加了 4 1.86 %和 4 5 .84 %。 CO2 浓度的倍增效应随着土壤干旱的增加而下降。 CO2 浓度倍增和土壤干旱都增加单位叶面积质量 (L MA) ,但 CO2 浓度倍增主要增加了水分充足时的 L MA。 CO2 倍增使柠条和羊柴叶片含氮量分别降低了 10 .4 0 %和 5 .0 6 %。柠条叶片含氮量在所有土壤干旱条件下均呈现出增加的趋势 ,而羊柴叶片的含氮量仅在严重干旱条件下增加。 CO2 倍增使叶片的碳氮比显著增加 ,但土壤干旱使之降低。CO2 浓度倍增降低叶肉细胞质膜的过氧化产物丙二醛 (MDA )的含量 ,干旱使之增加。叶片含氮量与 MDA呈显著正相关。研究表明 CO2 倍增有保护叶片免受严重土壤干旱的作用 ,但干旱的负面影响是 CO2CO_2 concentration in the atmosphere is expected to increase continuously in the future and would be doubled around the middle part of the 21^(th) century. CO_2 enrichment may take advantage of pant growth, but water stress is a common stress for plant growth and productivity. At present, only a few studies on the combined effects of CO_2 enrichment and drought on plant eco-physiology have been done. This experiment was conducted to investigate that the responses of two dominant desert shrubs (Caragana intermedia Kuanget H.c.Fu and Hedysarum mongolicum Turcz.) in western China to the interaction of doubled CO_2 and soil drought in a large environmental growth chambers (19 m^2). Compared with ambient CO_2 concentration, doubled CO_2 would increase the plant biomass by 62.90% and 50.00%, and the plant leaf area by 41.86% and 45.84%, of Caragana intermedia Kuanget H.c.Fu and Hedysarum mongolicum Turcz., respectively. The CO_2 fertilizer effect would decrease with the increase of soil drought. Both doubled CO_2 and soil drought would result in the increase of leaf mass per area unit (LMA). The increase of the LMA under doubled CO_2 would be more obvious under soil water sufficiency than under soil drought. Doubled CO_2 reduced leaf nitrogen concentration by 10.40% and 5.06%, of Caragana intermedia Kuanget H.c.Fu and Hedysarum mongolicum Turcz., respectively. Generally, the leaf nitrogen concentration of Caragana intermedia Kuanget H.c.Fu would increase under soil drought, but leaf nitrogen concentration of Hedysarum mongolicum Turcz. would increase only under severe soil drought. Both CO_2 enrichment and drought would not affect significantly leaf carbon concentration. Leaf C: N would be increased from 6.98 at ambient CO_2 concentration to 8.20 at doubled CO_2 for Caragana intermedia Kuanget H.c.Fu, and from 8.34 to 9.01 for Hedysarum mongolicum Turcz.; however, it would be affected significantly only under severe soil droughts, and this response for Caragana intermedia Kuanget H.c.Fu is more obvious than that for He

关 键 词：CO2浓度倍增 土壤干旱 柠条 羊柴 氮 碳 适应性 

分 类 号：Q948[生物学—植物学]