青海省沙珠玉治沙站17种主要植物叶性因子的比较

Comparisons of leaf traits among 17 major plant species in Shazhuyu Sand Control Experimental Station of Qinghai Province

国外大量研究结果表明,具有高叶氮含量和低比叶面积的干旱地区植物往往具有较高的水分利用效率。选取青海省沙珠玉治沙站地区17种主要植物(野生9种,人工8种) ,分别测定其比叶面积(SL A) ,单位重量叶氮含量(Nmass)及单位面积叶氮含量(Narea) ,并与贡嘎山湿润森林样带测定数据进行比较分析。结果表明,Nmass随SL A的增加而增加,但Nmass与SL A关系格局在固定沙丘野生多年生草本-灌木植物(类群1,Narea>3.0 g m- 2 )与流动沙丘野生短命草本植物(类群2 ,Narea<3.0 g m- 2 )之间存在策略位移现象,即在相同SL A下,类群1比类群2具有更高的叶氮含量,或在相同Nmass时类群1比类群2具有更小的比叶面积。在8个人工物种中,柠条锦鸡儿、中间锦鸡儿、绵柳和西北沙柳等灌木属于类群1,而甘草、小叶锦鸡儿、柽柳和青杨属于类群2 ,前者比后者具备更好的干旱适应机制,建议在生产上优先考虑前者。流动沙丘野生短命草本植物具有较低的叶氮含量和较高的比叶面积,这一特征与流动沙丘土壤贫瘠及其生长期内降水集中和土壤水分含量相对丰富密切相关。

Much evidence indicates that in arid environments, higher leaf nitrogen concentration and lower specific leaf area are generally correlated with higher water use efficiency. We measured specific leaf area (SLA), mass-based (N (mass)) and area-based (N (area)) leaf nitrogen concentrations for 17 native or introduced plant species in Shazhuyu Desert Control Experimental Station of Qinghai Province. The data were further compared with our previous data collected in the wet forests in the Gongga Mountains, eastern Tibetan Plateau. In general, N (mass) increased with increasing SLA. We found that there was a strategy shift in the N (mass) vs SLA relation patterns between the native perennial grasses and shrubs growing in the fixed sandy dune (Group-2, N (area)>3.0 g m^(-2)) and the native short-lived grasses growing in the moving sandy dune (Group-2, N (area)<3.0 g m^(-2)). Compared with Group-2 species, Group-1 species had a higher N (mass) at a given SLA or a lower SLA at a given N (mass). Among the eight introduced species, four shrubs for Aragana korshinskii, Caragana davazamcii, Salix suchowensis and Salix cheilophila belonged to Group-1, whereas others for Caragana microphylla, Amarix chinensis, Glycyrrhiza uralensis and Populus cathayana belonged to Group-2. We believe that the Group-1 introduced species would be more adaptive to the arid climate than the Group-2 planted species. The short-lived grasses (Group-2) for Agriophyllum squarrosum and Corispermum hyssopifolium had much higher SLA but relatively lower leaf nitrogen concentrations than the other species. The characteristics appear to be related to the low soil nitrogen content in the moving sandy dune and the relatively high soil water availability during the short growing seasons.