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Ecophysiological process regulates the growth of Cunninghamia lanceolata to suit short-term warming and nitrogen addition in the sub-tropical regions

Author:
Zhang, Qiufang, Xiong, Decheng, Xie, Jinsheng, Li, Xiaojie, You, Zhangtian, Lyu, Maokui, Chen, Yuehmin, Yang, Yusheng
Source:
Trees 2018 v.32 no.2 pp. 631-643
ISSN:
0931-1890
Subject:
Cunninghamia lanceolata, absorption, carbon, climate change, climatic factors, cytokinins, ecophysiology, forest management, gibberellins, hormones, indole acetic acid, leaves, nitrogen, nutrients, oxidants, peroxidase, photosynthesis, plasticity, soil heating, subtropics, temperature, uncertainty
Abstract:
KEY MESSAGE: Under warming condition, growth of Cunninghamia lanceolata is not accompanied by increased photosynthetic performance. The combination of warming and N addition seemed to adversely influence leaf carbon balance as Rd/Pnₘₐₓ and endogenous hormones were strongly affected. Uncertainties about the response of plant eco-physiological mechanisms to elevated temperature and nitrogen (N) deposition make it difficult to predict the performance of plants under future climatic conditions in the sub-tropical regions. We measured photosynthetic parameters, the contents of osmoregulatory substances, oxidant substances, protective enzymes, and endogenous hormones in Cunninghamia lanceolata under conditions of soil warming and N addition. We used six treatments: (1) unwarmed and unfertilized (CT), (2) unwarmed and high N (HN), (3) unwarmed and low N (LN), (4) warmed and unfertilized (W), (5) warmed and high N (WHN), and (6) warmed and low N (WLN). We found that the Rd/Pnₘₐₓ was the lowest in the W treatment, but the height was almost with the same as that of the CT. Plants under W showed plasticity of protective capacity by increasing peroxidase contents. N addition enhanced photosynthesis and promoted growth. The WLN treatments increased Rd/Pnₘₐₓ and decreased indoleacetic acid, gibberellin, and cytokinin contents, which might caused reduction in the absorption of nutrients and growth of the plants in the short-term. There were no significant differences in the content of osmoregulatory substances among the different treatments. We conclude different mechanisms may exist between W and N addition treatments that probably depend on adjustments through the physiological and biophysical processes. This study provides a new reference for forest management in view of the future climate changes.
Agid:
5913323