LUO Xuqiang1,2, ZHANG Guiling2,3, WANG Shijie2, RUAN Yinghui1, LIU Xin1,2, LI Yong2
（1. School of Geography and Resources, Guizhou Education University, Guiyang 550018, China;
2. Karst Ecosystem Observation Research Station in Puding, Chinese Academy of Sciences, Puding, Guiyang 562100, China;
3. College of Chemistry and Materials Engineering, Guiyang University, Guiyang 550005, China）
Abstract: Nitrogen is one of the most demanded mineral nutrients of plant. The isotopic fractionation of nitrogen happens in nitrogen cycling processes, e.g. chemical transformation and physical transport process. The stable nitrogen isotope ratio of plant is an integrating index of continuum interactions of soil-plant-atmosphere, and reflect a series of environmental information associated with physiological ecological processes of plant. In this study, in order to investigate affecting factors of the variation of nitrogen isotope compositions in plants in yellow soil regions of karst area and their relationship, we conducted researches in the Wangjia village, a small watershed of the karst plateau in Qingzhen, Guizhou. The leaf samples of four common plant species were collected in degraded plant communities with three different vegetation types and their contents of C, N, P, K, Ca and Mg as well as nitrogen stable isotope ratios were analyzed. The results showed that: (1) The δ15N values of leaves ranged from -3.25‰ to 0.69‰ (with an average of -1.04‰), with a distribution of high variation, large dispersion and negatively-skewed. (2) No significant difference (P>0.05) in δ15N values of plant leaves was found among different plant communities or/and different slope positions. (3) A trend of δ15N value was found among interspecies as Rosa cymosa (-0.03‰) > Pyracantha fortuneana (-0.24‰)>Lysimachia christinae(-1.58‰)>Rubus biflorus(-2.29‰), and the difference of their δ15N values was significant (P < 0.05). (4) The δ15N values of plant leaves in the study area were significantly affected by the interaction of community types and species factors (P = 0.016, R2 = 0.870). (5) The δ15N values of plant leaves in the study area were affected significantly by contents of K in leaves, and the stoichiometric ratios of C, N, P, K and Ca related closely. The regulation of K and Ca contents might be the key factor affecting the δ15N value of plant leaf in the yellow soil area.
Key words: stable nitrogen isotope ratio; karst plateau; yellow soil; degraded plant community; habitat heterogeneity; element stoichiometry
EARTH AND ENVIRONMENT Vol.47, No.2, Tot No.328, 2019, Page 113-120
