高寒沙地不同恢复年限沙棘叶片δ^(13)C和δ^(15)N变化特征及其影响因素  

Characteristics of leaves δ^(13) C and δ^(15) N of Hippophae Rhamnoide along different restoration years and influencing factors in an alpine desert

作　　者：李耀 田丽慧 汪海娇 何晓帆 金耀涛 LI Yao;TIAN Lihui;WANG Haijiao;HE Xiaofan;JIN Yaotao(State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University,Xining 810016,China)

机构地区：[1]青海大学省部共建三江源生态与高原农牧业国家重点实验室,西宁810016

出　　处：《生态学报》2025年第7期3267-3278,共12页Acta Ecologica Sinica

基　　金：国家自然科学基金(42301062);青海省科技厅项目(2023_ZJ_755)。

摘　　要：人工植被建植是青海湖流域沙地生态恢复的有效措施,揭示典型固沙植物的水分和养分利用效率,并分析影响其时间和空间变化的因素,有利于更好地理解固沙植被对高寒干旱环境有限资源的利用策略,为促进脆弱沙区的植被恢复提供有效的理论依据和实践指导。以青海湖东沙地不同恢复年限(1987年、2008年和2015年)栽植的沙棘为研究对象,利用稳定碳氮同位素技术测定植物叶片的δ^(13)C、δ^(15)N、单位质量叶的碳(C)含量(%)、氮(N)含量(%)并计算叶的碳氮比(C/N),基于土壤含水量、叶片含水量及局地气象因子等要素,探究δ^(13)C和δ^(15)N在季节和空间尺度的变化特征及其对局地土壤和气候环境的响应。结果表明:(1)在时间尺度上,沙棘叶片的δ^(13)C与δ^(15)N在生长季呈现出先减小后增大再减小的趋势,C含量呈先升高后降低再升高的趋势,N含量呈逐渐降低的趋势,而C/N则呈现逐渐升高的趋势。(2)在空间尺度上,幼龄林的δ^(13)C最高而老龄林最低,δ^(15)N值呈现相反的趋势,沙棘叶片的C含量、N含量及其C/N均没有表现出明显的差异。(3)δ^(13)C值在不同恢复年限沙棘中受到不同因子的影响,而δ^(15)N值与平均相对湿度(MRH)之间具有显著的负相关性(P<0.05)。沙棘δ^(13)C值的季节变化是气象因子综合作用的结果,而δ^(15)N值的季节变化是局地气象因子与叶片养分含量综合作用的结果。随着固沙年限的增加,沙棘的δ^(13)C值逐渐降低,而δ^(15)N值却在逐渐增加,固沙植被从幼龄向老龄演替进程中植物的水分利用效率(WUE)与氮素利用效率(NUE)之间具有权衡关系。Afforestation has been an effective measure for ecological restoration of desertification in Qinghai Lake basin since the 1980s.Revealing water and nutrient use efficiency of typical sand⁃fixing plantations and analyzing influencing factors at spatial⁃temporal scales would be beneficial,offering a better understanding of sand⁃fixing plantations′resource utilization strategies in alpine arid environments and providing valuable insights for vegetation restoration in fragile desert areas.We selected Hippophae rhamnoide along revegetation chronosequence(1987,2008,and 2015)in desert located on the eastern shore of Qinghai Lake as our study objects.Stable carbon and nitrogen isotope techniques were used to determine the δ^(13)C, δ^(15)N,carbon(C)and nitrogen(N)contents(%)per unit mass of leaves.Then we calculated the ratio of C and N.Based on soil water content,leaf water content and local meteorological data,we explored the spatio⁃temporal variation of δ^(13)C and δ^(15)N and their responses to pedon and local climate.The results showed that:(1)At the temporal scale, δ^(13)C and δ^(15)N values initially decreased,then increased,and subsequently decreased from May to October.While the content of C showed a fluctuation trend of increasing⁃decreasing⁃increasing,meanwhile,the content of N gradually decreased.However,C/N showed a trend of increasing along with seasons increasing.(2)At the spatial scale, δ^(13)C values were the highest in young stands and the lowest in old plantations,while δ^(15)N values showed the opposite trend,whereas the contents of per unit mass of leaves carbon and nitrogen and their ratios did not show any significant differences.(3)The values of δ^(13)C of were affected by different factors as restoration years increasing,while there was a significant negative correlation between the values of δ^(15) N and mean relative humidity(MRH)(P<0.05).The seasonal variation of δ^(13) C resulted from local climate influencing,whereas the seasonal variation of δ^(15) N was affected by

关 键 词：沙棘(Hippophae rhamnoides) 稳定碳同位素 稳定氮同位素 恢复年限 高寒沙地 

分 类 号：Q948[生物学—植物学]