Journal of Ecology and Rural Environment ›› 2020, Vol. 36 ›› Issue (3): 382-389.doi: 10.19741/j.issn.1673-4831.2019.0051

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Sulfur Dioxide Uptake by the Dominant Canopy Tree Species in a Natural Mixed Conifer-broadleaf Forest in Dinghushan, Guangdong Province, South China

DENG Yong-hong1,2, WANG Li-jing2,3, HUANG Jian-qiang1,2, MENG Ze1, LIU Shi-zhong1, OTIENO Dennis1,4, LI Yue-lin1   

  1. 1. South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China;
    4. Jaramogi Oginga Odinga University of Science and Technology, 210-40601 Bondo, Kenya
  • Received:2019-01-25 Online:2020-03-25 Published:2020-03-25

Abstract: The water use, biological characteristics, concentration of sulfur dioxide (SO2) and meteorological data were acquired by the sap flow measurements and environmental monitoring techniques. Based on the coupling relationship between water vapor and trace gas through two-dimensional exchange of pores, the canopy stomatal conductance for SO2 (GSO2), canopy SO2 uptake flux (FSO2), and accumulated stomatal SO2 flux (FSO2,st) of four dominant tree species (Pinus manssoniana, Castanopsis chinensis, Schima superba, and Machilus chinensis) in a natural mixed conifer-broadleaf forest at Dinghushan, south China were determined. The results show that, on a daily scale, the time at which the maximum concentration of SO2 appeared was partly overlapped the time when the maximum GSO2 occurred, and the maximum absorption of the four dominant tree species occurred at around noon time. On a seasonal scale, the average concentration of SO2 in the dry season (from October to March) was 10.11 nL·L-1, which was higher than that in the wet season (from April to September), 5.41 nL·L-1. The GSO2 of the four species was significantly higher in the wet season than that in the dry season (P<0.001), while the FSO2 in the wet season was higher than that in the dry season (P<0.001). Furthermore, the FSO2,st of C. chinensis and M. chinensis were 2.16 and 2.50 mmol·m-2, which were higher than 1.70 and of 1.91 mmol·m-2 for P. massoniana and S. superba, respectively. The SO2 stomatal absorption behavior of the four dominant tree species was mainly affected by factors such as vapor pressure deficit (VPD), photosynthetically active radiation (PAR) and SO2 concentration. This research provides the basic data for the reasonable evaluation of SO2 absorption flux in mixed coniferous-broadleaf forests in the Pearl River Delta region, and provides a basis for risk prevention for environmental assessment.

Key words: sap flow, mixed conifer-broadleaf forest, canopy stomatal conductance, sulfur dioxide, trace gas

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