Chinese Journal of Agrometeorology ›› 2023, Vol. 44 ›› Issue (04): 295-304.doi: 10.3969/j.issn.1000-6362.2023.04.004

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Comparison of Solar-induced Chlorophyll Fluorescence and Light Use Efficiency between Poplar and Cork Oak

CHENG Xiang-fen, REN Cheng-hao, ZHANG Jin-song, HU Mei-jun, JIANG Li-ya, HU Hai-yang, HUANG Hui, QIAO Yong-sheng   

  1. 1. Research Institute of Forestry, Chinese Academy of Forestry/Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Beijing 100091,China; 2. Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan 459007; 3. School of Electrical and Mechanical Engineering, Qingdao Agricultural University, Qingdao 266109; 4. College of Forestry, Henan Agricultural University, Zhengzhou 450002; 5. School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083; 6. State Owned Nanshan Forest Farm of Jiyuan City, Jiyuan 459000
  • Received:2022-05-06 Online:2023-04-20 Published:2023-04-15

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Abstract: Light use efficiency (LUE) is a key parameter connecting light absorption and carbon fixation and understanding the relationship between fluorescence and photosynthesis. Based on the absorbed energy dissipation pathways, LUE can be divided into light use efficiency of photosynthetic (LUEp) and light use efficiency of fluorescence (LUEf). The relationship between LUEp and LUEf of poplar and cork oak and the differences between species were explored in this study, to better understand the mechanism links between solar-induced chlorophyll fluorescence (SIF) and gross primary productivity (GPP) in deciduous broadleaf forests. In this study, the poplar (Populus alba × Populus gllandulosa) and cork oak (Quercus variabilis BI.) seedlings were used as the objects to measure the divergences in SIF and net photosynthetic rate (Pn) under the same soil moisture and nutrient conditions, to explore the responses of LUEp/LUEf to photosynthetically active radiation (PAR). The results showed that, (1) SIF was driven by incident PAR, SIF and PAR were significantly positively correlated. The coefficient of determination (R2) of poplar and cork oak were 0.965 and 0.973, respectively, and LUEf was higher in poplar. Pn gradually increased with increasing PAR. The light saturation point (LSP) of poplar was significantly higher than that of cork oak, which were 998.59 and 674 μmolCO2·m−2·s−1, respectively. (2) Pn first increased with the increasing SIF, and then the Pn of poplar was gradually saturated, while that of cork oak continued to slowly increase. (3) LUEp and LUEf showed significant negative linear correlation, and LUEp/LUEf decreased exponentially with increasing PAR, there was no significant difference in the change pattern and amplitude between tree species. During the daytime, with the increase of PAR, LUEf changed slightly, while LUEp decreased significantly, and the proportion of light energy allocation to carbon assimilation decreased. Therefore, Pn saturated under high light intensity, SIF and GPP showed exponential correlation in intraday scale, and the exponential relationship was consistent across tree species.

Key words: Solar-induced chlorophyll fluorescence, Net photosynthetic rate, Light use efficiency, Photosynthetically active radiation