Higher plant photosynthetic capability in autumn responding to low atmospheric vapor pressure deficit

Yawen Wang; Wenfang Xu; Wenping Yuan; Xiuzhi Chen; Bingwei Zhang; Lei Fan; Bin He; Zhongmin Hu; Shuguang Liu; Wei Liu; Shilong Piao

doi:10.1016/j.xinn.2021.100163

Higher plant photosynthetic capability in autumn responding to low atmospheric vapor pressure deficit

Innovation (Camb). 2021 Sep 23;2(4):100163. doi: 10.1016/j.xinn.2021.100163. eCollection 2021 Nov 28.

Authors

Yawen Wang¹, Wenfang Xu², Wenping Yuan², Xiuzhi Chen², Bingwei Zhang³, Lei Fan⁴, Bin He⁵, Zhongmin Hu⁶, Shuguang Liu⁷, Wei Liu⁸, Shilong Piao⁹

Affiliations

¹ Physical Oceanography Laboratory, College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China.
² School of Atmospheric Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Zhuhai 519082, China.
³ Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University at Zhuhai, Zhuhai 519087, China.
⁴ School of Geographical Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, China.
⁵ College of Global Change and Earth System Science, Beijing Normal University, Beijing 100038, China.
⁶ School of Geography, South China Normal University, Guangzhou 510631, China.
⁷ National Engineering Laboratory for Applied Technology of Forestry & Ecology in South China and College of Biological Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China.
⁸ State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
⁹ Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

Abstract

It has been long established that the terrestrial vegetation in spring has stronger photosynthetic capability than in autumn. However, this study challenges this consensus by comparing photosynthetic capability of terrestrial vegetation between the spring and autumn seasons based on measurements of 100 in situ eddy covariance towers over global extratropical ecosystems. At the majority of these sites, photosynthetic capability, indicated by light use efficiency (LUE) and apparent quantum efficiency, is significantly higher in autumn than in spring, due to lower atmosphere vapor pressure deficit (VPD) at the same air temperature. Seasonal VPD differences also substantially explain the interannual variability of the differences in photosynthetic capability between spring and autumn. We further reveal that VPD in autumn is significantly lower than in spring over 74.14% of extratropical areas, based on a global climate dataset. In contrast, LUE derived from a data-driven vegetation production dataset is significantly higher in autumn in over 61.02% of extratropical vegetated areas. Six Earth system models consistently projected continuous larger VPD values in spring compared with autumn, which implies that the impacts on vegetation growth will long exist and should be adequately considered when assessing the seasonal responses of terrestrial ecosystems to future climate conditions.

Keywords: carbon cycle; light use efficiency; vapor pressure deficit; vegetation index.