JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (2): 234-242.doi: 10.12302/j.issn.1000-2006.202107016

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Research progresses on stable isotopes of water transformation in SPAC system

LIN Wenqi1(), JIA Guodong1,2,*()   

  1. 1. School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
    2. Key Laboratory of Soil and Water Conservation and Desertification Combating, Ministry of Education, Beijing 100083, China
  • Received:2021-07-11 Revised:2022-03-22 Online:2023-03-30 Published:2023-03-28

Abstract:

The water conversion process of the soil-plant-atmosphere continuum (SPAC) system is an important research topic in ecological hydrology. Stable isotopes, as natural tracers, can effectively trace, integrate and indicate water input, output and transformation processes in the SPAC system. Based on a brief introduction of the application principle of stable isotopes, this study reviewed the progress of research within the context of vertical water transport at the soil-root interface; fractionation in plant water transport; and water exchange at the plant canopy-atmosphere interface based on stable isotope techniques. This study explored the limitations of stable isotopic techniques in terms of elucidating fractionation processes, temporal resolution and spatial heterogeneity in water transformation studies of SPAC systems. Finally, we conclude by providing corresponding suggestions for the future application and development of stable isotope technology. Specifically, we recommend that future research within the context of spac water conversion based on stable isotopes should focus on the following three aspects:(1)In situ observation of the isotopic composition of various isotopic pools with the help of portable isotopic analyzers. (2) Multi isotope analysis of pool isotope composition to analyze the water transport process at the soil root interface, to further determine the water source of trees, and subsequently improve the accuracy of source identification and division, and improve the stable isotope application model. (3) Using isotope labeled pot experiments to accurately control the water source of leaf water absorption, and to analyze the location and time of leaf water absorption at a more fine level. (4) Using controlled isotope labeling and centrifugal technology to extract juice from xylem vessels, the isotope deviation of each pool was compared and analyzed to further study the isotope fractionation mechanisms.

Key words: soil-plant-atmosphere continuum (SPAC), stable isotope, water source, foliar water uptake(FWU), isotope fractionations

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