鬼箭锦鸡儿叶片和土壤碳稳定同位素特征及其影响因素

为探究高海拔地区的植物碳(C)循环过程与其生境的关系,以生长在高山地区的豆科灌木鬼箭锦鸡儿为研究对象,沿着横跨我国东西部山区的样带采集35个样点的鬼箭锦鸡儿叶片和土壤样品,分析了鬼箭锦鸡儿叶片碳稳定同位素组成(δ¹³C)、土壤δ¹³C、叶片和土壤δ¹³C差值(Δδ¹³C)在不同采样点的特征及其与气候因子、叶片和土壤元素的关系。结果表明:鬼箭锦鸡儿叶片δ¹³C的变化范围为-30.9‰～-27.1‰,平均值为-28.4‰,土壤δ¹³C的变化范围为-26.2‰～-23.2‰,平均值为-25.3‰,Δδ¹³C的变化范围为2.0‰～7.7‰,平均值为3.1‰;叶片δ¹³C显著低于土壤δ¹³C,且随着叶片δ¹³C增加,土壤δ¹³C先降低后升高;叶片δ¹³C与生长季均温和叶片C含量呈显著负相关,土壤δ¹³C与相对湿度和最暖月均温呈显著负相关,与土壤碳∶氮(C∶N)呈显著正相关,随土壤C含量的增加土壤δ¹³C先降低后升高,Δδ¹³C与叶片C含量、土壤C含量和土壤C∶N呈显著正相关;气候因子对叶片δ¹³C和Δδ¹³C具有直接影响,同时也通过对叶片和土壤元素的影响,间接导致叶片δ¹³C、土壤δ¹³C和Δδ¹³C的改变。高海拔地区的气候因子、叶片和土壤元素共同影响鬼箭锦鸡儿的C循环过程。

Characteristics and influence factors in leaf and soil carbon stable isotopes of Caragana jubata.

In order to explore the relationship of plant carbon (C) cycling with its habitat in the high-altitude regions, a leguminous shrub, Caragana jubata, that mainly distributed in those areas was studied. We collected leaf and soil samples of C. jubata from 35 sites along an east-west transect across the alpine regions of China. We measured leaf carbon stable isotope (δ¹³C), soil δ¹³C, and the difference between leaf and soil δ¹³C (Δδ¹³C) of each sampling site. We further analyzed the effects of climatic factors, leaf and soil elements on leaf δ¹³C, soil δ¹³C and Δδ¹³C. Results showed that leaf δ¹³C ranged from -30.9‰ to -27.1‰, with a mean value of -28.4‰, soil δ¹³C ranged from -26.2‰ to -23.2‰, with a mean value of -25.3‰, and Δδ¹³C ranged from 2.0‰ to 7.7‰, with a mean value of 3.1‰. δ¹³C values of leaf was significantly lower than that of soil. Soil δ¹³C initially decreased and subsequently increased with increasing leaf δ¹³C. Leaf δ¹³C was negatively correlated with growing season temperature and leaf C content. Soil δ¹³C was negatively correlated with relative humidity and mean temperature of the warmest month, and was positively correlated with soil carbon:nitrogen (C:N). Soil δ¹³C firstly decreased and subsequently increased with soil C content. Δδ¹³C was positively correlated with leaf C content, soil C content, and soil C: N. Climatic factors directly affected leaf δ¹³C and Δδ¹³C, and indirectly affected leaf δ¹³C, soil δ¹³C and Δδ¹³C through their effects on leaf and soil elements. The C cycle of C. jubata was affected by climatic factors, leaf and soil elements in the alpine regions.