JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2021, Vol. 45 ›› Issue (6): 135-142.doi: 10.12302/j.issn.1000-2006.202003057

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Ecological stoichiometry in leaves, branches and roots of Torreya grandis with different forest ages and its stoichiometric homoeostasis

YUAN Yanan(), LI Zhengca*(), WANG Bin, ZHANG Yujie, HUANG Shengyi   

  1. Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
  • Received:2020-03-18 Accepted:2020-11-20 Online:2021-11-30 Published:2021-12-02
  • Contact: LI Zhengca E-mail:2711615933@qq.com;lizccaf@126.com

Abstract:

【Objective】 The objective of this study is to investigate C, N and P stoichiometric characteristics and stoichiometric homoeostasis of Torreya grandis.【Method】 The T. grandis of different ages (0-100, ≥100-300, ≥300-500 and ≥500 a) were selected from Zhuji National Forest Park of Zhejiang Province. The plant samples (roots, branches and leaves) and 0-20 cm soil samples of T. grandis of different ages were collected from the field to analyze the C, N and P stoichiometric characteristics and stoichiometric homoeostasis.【Result】 There were no significant differences in C, N and P concentrations and stoichiometric characteristics of T. grandis of different ages. The concentrations of C, N and P were the highest in ≥300-500 a, and the concentrations of C and N in branches and leaves were the lowest in ≥500 a, while the concentrations of P in roots were the lowest in ≥100-300 a, and the N/P of leaves of different ages was lower than the threshold of N limitation of 14. The concentrations of C, N and P in different organs showed the same trend: leaf > branch > root. The concentrations of C and P in leaves and branches were significantly higher than those in roots, and the concentrations of N in leaves were significantly higher than those in roots and branches. Overall, the concentrations of N and P in all organs showed a positive relationship, and were significantly correlated in branches (P<0.01). Further, there were significant differences in the stoichiometric characteristics of different organs of T. grandis. The C/N ratios of roots and branches were significantly higher than those of leaves, the C/P ratio of roots was significantly higher than those of branches and leaves, and stoichiometric homoeostasis of P (HP) and (HN/P) was found in T. grandis. In addition, The N/P ratio (HN/P =20.00) had a higher degree of stoichiometric homoeostasis than P concentration (HP =11.76). 【Conclusion】 The C, N, P ratios of T. grandis did not differ with age, but those of organs did. The growth of T. grandis was mostly limited by soil N, therefore, fertilization may thus promote the growth of T. grandis at all growing stages.

Key words: Torreya grandis forest, age, root, branch, leaf, stoichiometry, stoichiometric homoeostasis

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