Main content area

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

Zhang, Qiufang, Xiong, Decheng, Xie, Jinsheng, Li, Xiaojie, You, Zhangtian, Lyu, Maokui, Chen, Yuehmin, Yang, Yusheng
Trees 2018 v.32 no.2 pp. 631-643
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
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.