Investment of needle nitrogen to photosynthesis controls the nonlinear productivity response of young Chinese fir trees to nitrogen deposition

Renshan Li; Dan Yu; Yankuan Zhang; Jianming Han; Weidong Zhang; Qingpeng Yang; Arthur Gessler; Mai-He Li; Ming Xu; Xin Guan; Longchi Chen; Qingkui Wang; Silong Wang

doi:10.1016/j.scitotenv.2022.156537

Investment of needle nitrogen to photosynthesis controls the nonlinear productivity response of young Chinese fir trees to nitrogen deposition

Sci Total Environ. 2022 Sep 20:840:156537. doi: 10.1016/j.scitotenv.2022.156537. Epub 2022 Jun 6.

Authors

Renshan Li¹, Dan Yu², Yankuan Zhang³, Jianming Han², Weidong Zhang⁴, Qingpeng Yang⁵, Arthur Gessler⁶, Mai-He Li⁷, Ming Xu⁸, Xin Guan⁹, Longchi Chen⁹, Qingkui Wang⁹, Silong Wang⁹

Affiliations

¹ Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China; Life Science Department, Luoyang Normal University, Luoyang 471934, China.
² Life Science Department, Luoyang Normal University, Luoyang 471934, China.
³ Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China; University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China; Huitong National Research Station of Forest Ecosystem, Huitong 418307, China. Electronic address: wdzhang@iae.ac.cn.
⁵ Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China; Huitong National Research Station of Forest Ecosystem, Huitong 418307, China. Electronic address: yqp226@iae.ac.cn.
⁶ Forest Dynamics, Swiss Federal Research Institute WSL, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland.
⁷ Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China; Forest Dynamics, Swiss Federal Research Institute WSL, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland.
⁸ BNU-HKUST Laboratory for Green Innovation, Beijing Normal University, Zhuhai 519085, China.
⁹ Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China; Huitong National Research Station of Forest Ecosystem, Huitong 418307, China.

PMID: 35679936
DOI: 10.1016/j.scitotenv.2022.156537

Abstract

Plant carbon (C) assimilation is expected to nonlinearly increase with continuously increasing nitrogen (N) deposition, causing a N saturation threshold for productivity. However, the response of plant productivity to N deposition rates and further the N saturation threshold still await comprehensive quantization for forest ecosystem. Here, we tested the effect of N addition on aboveground net primary productivity (ANPP) of three-year old Chinese fir (Cunninghamia lanceolata) trees by adding N at 0, 5.6, 11.2, 22.4, and 44.8 g N m^-2 yr^-1 for 2.5 years. The N saturation threshold was estimated based on a quadratic-plus-plateau model. Results showed that ANPP transitioned from an increasing stage with increasing N addition rate to a plateaued stage at an N rate of 16.3 g N m^-2 yr^-1. The response of ANPP to N addition rates was well explained by the net photosynthetic rates of needles. Results from the dual isotope measurement [simultaneous determination of needle stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotopes] indicated that the photosynthetic capacity, rather than the stomatal conductance, mediated the response of photosynthesis and ANPP of the young Chinese fir trees to N addition. Accordingly, the amount of needle N partitioning to water-soluble fraction, which is associated with the photosynthetic capacity, also responded to N enrichment with a nonlinear increase. Our study will contribute to a more accurate prediction on the influence of N deposition on C cycles in Chinese fir plantations.

Keywords: Dual isotope approach; Foliar age effect; Forest C uptake; Nitrogen amendment.

MeSH terms

Abies*
Carbon
Cunninghamia*
Ecosystem
Needles
Nitrogen
Photosynthesis / physiology
Plant Leaves / physiology
Plants
Trees

Substances

Carbon
Nitrogen