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Tradeoff in the supply and demand for CO 2 dominates the divergence of net photosynthesis rates of functional plants in alpine ecosystems
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  • Hongyun Yao,
  • Xiao-Yan Li,
  • Cicheng Zhang,
  • Pei Wang,
  • Fangzhong Shi,
  • Yujing Deng
Hongyun Yao
Beijing Normal University

Corresponding Author:hyyao@mail.bnu.edu.cn

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Xiao-Yan Li
Beijing Normal University
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Cicheng Zhang
Hunan Normal University
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Pei Wang
Beijing Normal University
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Fangzhong Shi
Beijing Normal University
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Yujing Deng
Beijing Normal University
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Abstract

As regional heterogeneity on the Qinghai Tibetan Plateau (QTP), the “greening rate” between alpine steppe in the west and alpine meadow ecosystems in the east is difference during the past several decades. To investigate the difference, the net photosynthetic rate (An) and the supply (mesophyll conductance ( g m), stomatal conductance ( g s)) and demand (the maximum rates of Rubisco carboxylase activity ( V cmax) and photosynthetic electron transport ( J max)) for CO 2 of three plants functional types (PFTs) were measured. Other functional traits and influencing factors were compared among ecosystems along the altitudinal gradients of QTP. The An of the PFTs was simulated under potential future conditions. At high altitudes, grass was found to maintain a relatively stable An by decreasing V cmax, J max, and g s, while slightly increasing g m, compared with that at a low altitude. The An of sedge and shrubs increased with rising V cmax, J max and g s and g m values, resulting in a large increment in the An at low altitudes. Grass seemed to be less sensitive to the environment by reducing the supply of and holding onto CO 2, while sedge and shrub increased both. Grass and sedge should be divided into two PFTs rather than remaining as one based on their opposite physiological and morphological functions in response to climate change. The ecosystem at 3600 m was transitional. C a was likely to be a more dominant factor than T a in affecting the An of grass. The order of rising An in PFTs was shrub > sedge > grass and the An of alpine meadow was found to increase more under the two future climate scenarios.
03 Nov 2021Submitted to Ecohydrology
03 Nov 2021Submission Checks Completed
03 Nov 2021Assigned to Editor
10 Nov 2021Review(s) Completed, Editorial Evaluation Pending
11 Nov 2021Reviewer(s) Assigned
11 Mar 2022Editorial Decision: Revise Major
27 Aug 20221st Revision Received
29 Aug 2022Submission Checks Completed
29 Aug 2022Assigned to Editor
29 Aug 2022Review(s) Completed, Editorial Evaluation Pending
23 Sep 2022Editorial Decision: Accept
17 Oct 2022Published in Ecohydrology. 10.1002/eco.2487