JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2017, Vol. 60 ›› Issue (02): 27-33.doi: 10.3969/j.issn.1000-2006.2017.02.005

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Stoichiometric characteristics of leaf carbon, nitrogen and phosphorus in forest ecosystems in the head of the Three Gorges Reservoir Area

LIU Zebin1, CHENG Ruimei1,2*, XIAO Wenfa1, WANG Na1   

  1. 1. Key Laboratory of Forest Ecology and Environment, State Forestry Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China;
    2. Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
  • Online:2017-04-18 Published:2017-04-18

Abstract: 【Objective】 Forests are important ecological barriers for the Three Gorges Reservoir Area. Therefore, a study on the stoichiometric characteristics of forest ecosystems in this area was conducted to provide significant understanding of the nutrient cycle, limiting effects and stabilizing mechanisms of ecosystems. 【Method】 A total of 107 samples from forest ecosystems at seven sites in the head of the Three Gorges Reservoir Area was collected to study the stoichiometric characteristics of carbon(C), nitrogen(N)and phosphorus(P)in leaves of 30 plant species(including trees, shrubs and herbs). 【Result】 The C, N and P contents in leaves varied within the ranges of 352.0-506.3, 8.3-48.6 and 0.5-2.5 mg/g, with the averages of 450.2, 18.6 and 1.2 mg/g, respectively. The ratios of C/N, C/P and N/P in leaves were in the ranges of 7.6-56.5, 158.8-799.3 and 7.3-40.2, with the averages of 28.6, 450.4 and 16.9, respectively. The nutrient compositions differed significantly among the plant types. The C content of leaves was significantly higher in trees than in shrubs and herbs, and the N and P contents in leaves were significantly higher in herbs than in trees and shrubs. Compared with evergreen trees, N and P contents and N/P ratio in the leaves of deciduous trees were significantly high whereas the C content and C/N and C/P ratios were significantly low. The relationships between leaf C and N(P)content also showed significant differences among the plant types. There was a highly significantly, negative correlation between the C and N(P)contents in herb leaves, but C content was significantly negatively correlated to N content, and there was no significant correlation to P content in trees. There was no significant correlation between the C and N(P)contents in shrubs. The N and P contents were significantly, positively correlated in leaves of all plant types. 【Conclusion】 In the forest ecosystems of the head of the Three Gorges Reservoir Area, the C content of leaves was medium, whereas the N and P contents in leaves were relatively lower. Our results suggest that P deficiency is the key limiting element for vegetation productivity.

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