JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2025, Vol. 49 ›› Issue (1): 128-136.doi: 10.12302/j.issn.1000-2006.202303031

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The individual scale water-carbon coupling process of Platycladus orientalis under CO2 and water stress in Beijing mountainous area

ZHANG Longqi1(), ZHANG Yong’e2, JIA Guodong1,*(), LYU Xiangrong1, ZHANG Xiao1, LEI Ziran1, LIU Rui1   

  1. 1. Key Laboratory of State Forestry and Grassland Administration on Soil and Water Conservation, the Metropolitan Area Forest Ecosystem Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
    2. Institute of Sediment Research, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
  • Received:2023-03-11 Revised:2024-01-20 Online:2025-01-30 Published:2025-01-21
  • Contact: JIA Guodong E-mail:zlq1255676314@163.com;jgd3@163.com

Abstract:

【Objective】In arid and semiarid regions, efficient water use for vegetation construction and restoration to maximize functional diversity has become a key research focus due to scarce precipitation. The study of plant water-carbon coupling processes is crucial in this context.【Method】This research focused on Platycladus orientalis, the main afforestation species in Beijing mountainous areas. An indoor pot simulation experiment was conducted over six months to measure the individual transpiration water consumption, carbon sequestration, and respiration rate of P. orientalis under different CO2 concentrations and soil moisture levels. Water use efficiency was used as the water-carbon coupling index to analyze these processes and their influencing factors. 【Result】(1)The transpiration rate of P. orientalis was significantly affected by soil water content, peaking at 70%-80% field water capacity and then slightly decreased. (2) Both soil water content and CO2 concentration significantly influenced individual carbon processes and water-carbon coupling. (3) Instantaneous and short-term water use efficiency reached maximum at CO2 concentrations of 600 and 800 μmol/mol with 50%-60% field water capacity. (4) There was a significant linear correlation between cumulative carbon sequestration and water consumption (P < 0.05), with a maximum ratio of 24.35 mmol/mol at a CO2 concentration of 800 μmol/mol and 50%-60% field water capacity. 【Conclusion】The increase of carbon dioxide concentration was conducive to alleviating the individual scale drought stress, and soil water content significantly affected the water-carbon process of P. orientalis.

Key words: water-carbon coupling, vegetation, water use efficiency, carbon dioxide, water stress, Platycladus orientalis

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