兰州市42种园林木本植物叶片碳氮磷化学计量特征

Stoichiometric characteristics of carbon,nitrogen and phosphorus in the leaves of 42 woody landscape plants in Lanzhou City of northwestern China

【目的】植物叶片碳(C)、氮(N)、磷(P)含量及其比值是植物长期适应环境的结果,研究西北干旱区域园林木本植物叶片化学计量特征可以为同类城市园林木本植物的精准规划及大尺度模型的构建提供数据基础。【方法】该研究对兰州市主城区(七里河区、安宁区、西固区)42种常见园林木本植物叶片的C、N、P化学计量特征进行了分析。将42种植物按照乔木(26种)和灌木(16种)、常绿(7种)和落叶(35种)及针叶(5种)和阔叶(37种)进行分类,分析不同生活型植物叶片C、N、P、C∶N、C∶P和N∶P的变异特征及与比叶重(LMA)的关系。【结果】(1)42种园林木本植物叶片平均C含量为39.67%、N含量为2.45%、P含量为0.17%,C∶N、C∶P和N∶P平均值分别为17.17、232.98和14.72。与全球尺度相比,兰州市木本植物叶片C、P含量和C∶N相对较低,而叶片N∶P相对较高。(2)不同生活型植物化学计量特征不同,乔木叶片C含量、C∶N、C∶P和N∶P高于灌木,而N和P含量低于灌木;落叶树种叶片N、P含量高于常绿树种;阔叶树种叶片N、P含量高于针叶树种。(3)对植物叶片性状之间的相互关系分析显示:植物叶片C含量与C∶N、C∶P呈极显著正相关(P<0.01);LMA与叶片C含量表现出协同关系,与叶片N、P含量均表现出相反的关系。【结论】初步判定兰州市园林木本植物在生长季受N元素的限制,建议在本区域生态环境治理时可适当增施N肥。

[Objective]The contents and ratios of carbon(C),nitrogen(N)and phosphorus(P)in plant leaves are the results of long-term adaptation of plants to the environment.Study of leaf stoichiometry characteristics of woody landscape plants in arid areas of northwestern China can provide a data basis for the accurate planning and construction of large-scale models of planting in similar cities.[Method]In this study,the C,N and P stoichiometric characteristics of 42 common woody landscape plants in the main urban district of Lanzhou City of northwestern China(Qilihe District,Anning District and Xigu District)were analyzed.The 42 plant species were classified into trees(26 species)and shrubs(16 species),evergreen(7 species)and deciduous(35 species),coniferous(5 species)and broadleaved(37 species).Variation characteristics of leaves’contents of C,N,P,C∶N,C∶P and N∶P of different life types,and the relationship between the variation characteristics and specific leaf mass(LMA)were analyzed.[Result](1)The average contents of C,N and P of 42 woody landscape plants were 39.67%,2.45% and 0.17%,respectively.The average C∶N,C∶P and N∶P were 17.17,232.98 and 14.72,respectively.Compared with the global scale,the contents of C and P and C∶N in leaves of woody plants in Lanzhou City were relatively low,while the contents of N∶P in leaves were relatively high.(2)Stoichiometric characteristics varied among different plant life types.The C content,C∶N,C∶P and N:P of the leaves of trees were higher than those of shrubs,and the content of N and P was lower than that of shrubs.The leaf N and P content of deciduous tree species was higher than that of evergreen tree species.The leaves of broadleaved tree species had higher leaf N and P content than coniferous tree species.(3)The analysis of the correlations between plant leaf traits showed that leaf C content was positively correlated with C∶N and C∶P(P<0.01).There was a synergistic relationship between LMA and leaf C content,but an opposite relationship between LMA and leaf N and P content.[Conclusion]It is preliminarily indicated that the development of woody landscape plants in Lanzhou City is limited by N elements during the growing season,and it is suggested that nitrogenous fertilizer can be increased appropriately during the ecological environmental improvement in this area.