Leaf photosynthetic pigment as a predictor of leaf maximum carboxylation rate in a farmland ecosystem

Yue Li; Qingtao Wang; Taimiao Fu; Yunfeng Qiao; Lihua Hao; Tao Qi

doi:10.3389/fpls.2023.1225295

Leaf photosynthetic pigment as a predictor of leaf maximum carboxylation rate in a farmland ecosystem

Front Plant Sci. 2023 Jul 4:14:1225295. doi: 10.3389/fpls.2023.1225295. eCollection 2023.

Authors

Yue Li¹, Qingtao Wang², Taimiao Fu², Yunfeng Qiao³, Lihua Hao⁴, Tao Qi²

Affiliations

¹ School of Earth Science and Engineering, Hebei University of Engineering, Handan, China.
² School of Landscape and Ecological Engineering, Hebei University of Engineering, Handan, China.
³ Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
⁴ School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China.

Abstract

The leaf maximum rate of carboxylation (V_cmax) is a key parameter of plant photosynthetic capacity. The accurate estimation of V_cmax is crucial for correctly predicting the carbon flux in the terrestrial carbon cycle. V_cmax is correlated with plant traits including leaf nitrogen (N_area) and leaf photosynthetic pigments. Proxies for leaf chlorophyll (Chl_area) and carotenoid contents (Car_area) need to be explored in different ecosystems. In this study, we evaluated the relationship between leaf maximum rate of carboxylation (scaled to 25°C; V_cmax25) and both leaf N_area and photosynthetic pigments (Chl_area and Car_area) in winter wheat in a farmland ecosystem. Our results showed that V_cmax25 followed the same trends as leaf Chl_area. However, leaf N_area showed smaller dynamic changes before the flowering stage, and there were smaller seasonal variations in leaf Car_area. The correlation between leaf V_cmax25 and leaf Chl_area was the strongest, followed by leaf Car_area and leaf N_area (R² = 0.69, R² = 0.47 and R²= 0.36, respectively). The random forest regression analysis also showed that leaf Chl_area and leaf Car_area were more important than leaf N_area for V_cmax25. The correlation between leaf V_cmax25 and N_area can be weaker since nitrogen allocation is dynamic. The estimation accuracy of the V_cmax25 model based on N_area, Chl_area, and Car_area (R²= 0.75) was only 0.05 higher than that of the V_cmax25 model based on Chl_area and Car_area (R²= 0.70). However, the estimation accuracy of the V_cmax25 model based on Chl_area and Car_area (R²= 0.70) was 0.34 higher than that of the V_cmax25 model based on N_area (R²= 0.36). These results highlight that leaf photosynthetic pigments can be a predictor for estimating V_cmax25, expanding a new way to estimate spatially continuous V_cmax25 on a regional scale, and to improve model simulation accuracy.

Keywords: leaf carotenoid content; leaf chlorophyll content; leaf nitrogen content; maximum rate of carboxylation; photosynthetic capacity.

Grants and funding

This work was co-supported by the National Natural Science Foundation of China (32001130) and Natural Science Foundation of Hebei Province, China (Grant No. C2021402011, C2020402022, E2021402031).