Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (1): 114-122.DOI: 10.17521/cjpe.2022.0085

Special Issue: 稳定同位素生态学

• Research Articles • Previous Articles     Next Articles

Foliar assimilation and distribution of NO2 in Schima superba and Pinus massoniana seedlings using 15N stable isotope tracing technique

YAO Meng1,2, KANG Rong-Hua1,3,*(), WANG Ang1,3, MA Fang-Yuan4, LI Jin1, TAI Zi-Han1,2, FANG Yun-Ting1,3   

  1. 1Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3Key Laboratory of Stable Isotope Techniques and Applications, Liaoning Province, Shenyang 110016, China
    4Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
  • Received:2022-03-07 Accepted:2022-04-22 Online:2023-01-20 Published:2022-08-26
  • Contact: *KANG Rong-Hua(kangrh@iae.ac.cn)
  • Supported by:
    National Key R&D Program of China(2020YFA0608100);Hundred Talents Program of Chinese Academy of Sciences(2019000186);Shandong Taishan Scholar Young Expert Program

Abstract:

Aims Nitrogen oxides (NOx = NO + NO2) are the world’s main atmospheric pollutants. Especially in China, NOx deposition has been increasing in recent years. When NOx enter the forest ecosystems accompanied by dry deposition, they reach the forest canopy first. Studies have shown that trees can assimilate NO2 deposited on leaf surfaces, but this process has been ignored in the forest N cycle models. Currently, the quantity of NO2 that can be assimilated by trees through foliage and the mechanisms of how the assimilated NO2 is distributed remain unclear.
Methods In this study, we conducted a 15NO2 fumigation experiment with static chambers under dark and light conditions. We chose Schima superba and Pinus massoniana seedlings, the common tree species in southern China, as our experimental materials, and analyzed the whole 15N recovery and the distribution of assimilated 15NO2 in different tissues.
Important findings The results show that trees assimilated NO2 mainly through stomata. Schima superba and P. massoniana could take up 10.3% ± 5.9% and 20.4% ± 7.0% 15NO2 in the whole plant under the dark condition, respectively; while 35.9% ± 5.4% and 68.2% ± 7.6% under light condition. The sequence of 15N recovery per dry mass in different tissues was leaves > branches > stem > roots. Most recovered NO2 remained in the leaves in a short period after fumigation. The 15N recovery in leaves of S. superba and P. massoniana accounted for 72% and 49% of the total recovery under the dark condition, and 91% and 96% under the light condition, respectively. This study indicates that the foliar assimilation of NO2 in forest ecosystems cannot be ignored. The process of foliar NO2 assimilation plays a key role in the N budget of forest ecosystems.

Key words: 15NO2, 15N stable isotope tracing technique, static fumigation, foliar N assimilation, N distribution, tree seedling