Drought stress strengthens the link between chlorophyll fluorescence parameters and photosynthetic traits

Jie Zhuang; Yonglin Wang; Yonggang Chi; Lei Zhou; Jijing Chen; Wen Zhou; Jun Song; Ning Zhao; Jianxi Ding

doi:10.7717/peerj.10046

Drought stress strengthens the link between chlorophyll fluorescence parameters and photosynthetic traits

PeerJ. 2020 Sep 24:8:e10046. doi: 10.7717/peerj.10046. eCollection 2020.

Authors

Jie Zhuang^#¹, Yonglin Wang^#¹, Yonggang Chi^{1

2}, Lei Zhou^{1

3}, Jijing Chen¹, Wen Zhou¹, Jun Song¹, Ning Zhao¹, Jianxi Ding¹

Affiliations

¹ College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China.
² State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
³ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.

^# Contributed equally.

Abstract

Chlorophyll fluorescence (ChlF) has been used to understand photosynthesis and its response to climate change, particularly with satellite-based data. However, it remains unclear how the ChlF ratio and photosynthesis are linked at the leaf level under drought stress. Here, we examined the link between ChlF ratio and photosynthesis at the leaf level by measuring photosynthetic traits, such as net CO₂ assimilation rate (A_n), the maximum carboxylation rate of Rubisco (V_cmax), the maximum rate of electron transport (J_max), stomatal conductance (g_s) and total chlorophyll content (Chl_t). The ChlF ratio of the leaf level such as maximum quantum efficiency of PSII (F_v/F_m) is based on fluorescence kinetics. ChlF intensity ratio (LD₆₈₅/LD₇₄₀) based on spectrum analysis was obtained. We found that a combination of the stomatal limitation, non-stomatal limitation, and Chl_t regulated leaf photosynthesis under drought stress, while J_max and Chl_t governed the ChlF ratio. A significant link between the ChlF ratio and A_n was found under drought stress while no significant correlation in the control, which indicated that drought stress strengthens the link between the ChlF ratio and photosynthetic traits. These results suggest that the ChlF ratio can be a powerful tool to track photosynthetic traits of terrestrial ecosystems under drought stress.

Keywords: Chlorophyll content; Chlorophyll fluorescence spectrum; Jmax; Remote sensing; Vcmax; gs.

Grants and funding

This study was supported financially by the Zhejiang Provincial Natural Science Foundation of China (LY19C030004), the National Key Research and Development Program of China (2017YFB0504000 and 2016YFB0501501), the National Natural Science Foundation of China (41871084 and 31400393), and a grant from State Key Laboratory of Resources and Environmental Information System. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.