Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (10): 962-970.DOI: 10.17521/cjpe.2015.0093

• Orginal Article • Previous Articles     Next Articles

C, N and P stoichiometry of two dominant seedlings and their responses to nitrogen additions in the montane moist evergreen broad-leaved forest in Ailao Mountains, Yunnan

SHI Xian-Meng1,2,*, QI Jin-Hua3,*, SONG Liang1,**(), LIU Wen-Yao1, HUANG Jun-Biao1,2, LI Su1, LU Hua-Zheng1,2, CHEN Xi1,2   

  1. 1Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, Yunnan 676209, China
  • Online:2015-10-01 Published:2015-10-24
  • Contact: Xian-Meng SHI,Jin-Hua QI,Liang SONG
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    # Co-first authors

Abstract: <i>Aims</i>

Montane moist evergreen broad-leaved forest is an important vegetation type in the high altitude areas of western China. In this study, total carbon (C), nitrogen (N), phosphorus (P) contents and stoichiometry in roots, stems, and leaves of two dominant seedlings, Symplocos ramosissima and Machilus gamblei, and their responses to different levels of N addition were investigated in the montane moist evergreen broad-leaved forest in Ailao Mountains, Yunnan.

<i>Methods</i>

A simulation experiment with four N addition levels T0 (0 kg N·hm-2·a-1), T1 (3 kg N·hm-2·a-1), T2 (6 kg N·hm-2·a-1) and T3 (12 kg N·hm-2·a-1) was carried out in the montane moist evergreen broad-leaved forest in Ailao Mountains. Total C, N and P concentrations in different organs of the two dominant seedlings and soil inorganic N concentration in each treatment were measured after one year’s in situ experiment.

<i>Important findings</i>

The C, N and P concentrations of the two seedlings were significantly different (p < 0.05). Machilus gamblei had lower C concentration, but higher N and P concentrations compared with S. ramosissima. N addition had significant effects (p < 0.01) on C, N and P concentrations and their stoichiometry. Significant interactions were detected among N treatments, species and plant organs. N addition increased N concentrations in all organs of the two seedlings, leading to higher ratio of N:P. P concentration of S. ramosissima decreased significantly (p < 0.05) under N addition, while that of M. gamblei increased under medium (T2) and high (T3) N addition treatments. Within a certain range, there was a significant correlation between the N concentrations of seedlings and soil inorganic N concentrations (p < 0.01). Comparisons of homeostasis index among different organs indicated that the N stoichiometry in roots and stems was more stable than that in leaves under N addition.

Key words: ecological stoichiometry, nitrogen deposition, primary forest, homeostasis, seedlings