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ORIGINAL RESEARCH article

Front. Plant Sci.
Sec. Crop and Product Physiology
Volume 15 - 2024 | doi: 10.3389/fpls.2024.1465925
This article is part of the Research Topic Ecometabolomics of Crop Responses to Climate Change: Acclimation, Alleviation, and Resilience View all articles

Shade tolerance in wheat is related to photosynthetic limitation and morphological and physiological acclimations

Provisionally accepted
Yong Li Yong Li 1,2Jiarong Zhao Jiarong Zhao 3Hongliang Ma Hongliang Ma 3Lixia Pu Lixia Pu 3Xiulan Huang Xiulan Huang 3Hongkun YANG Hongkun YANG 1,2,3,4*Gaoqiong Fan Gaoqiong Fan 1,2,3,4*
  • 1 Sichuan Agricultural University, Ya'an, China
  • 2 State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, Sichuan Province, China
  • 3 Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, Sichuan Province, China
  • 4 Crop Eco-physiology and Cultivation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China

The final, formatted version of the article will be published soon.

    Low solar irradiance reaching the canopy due to fog and heavy haze is a significant yield-limiting factor worldwide. However, how plants adapt to shade stress and the mechanisms underlying the reduction in leaf photosynthetic capacity and grain yield remain unclear. In this study (conducted during 2018–2021), we investigated the impact of light deprivation (60%) at the pre-anthesis and post-anthesis stages on leaf carboxylation efficiency, source-to-sink relationships, sucrose metabolism, and grain yield of wheat cultivars with contrasting shade tolerance. Shade stress decreased stomatal conductance, stomatal limitation value, intrinsic water use efficiency, rubisco activity, and carboxylation efficiency of flag leaves during grain-filling, whereas intercellular CO2 concentration increased. These findings indicate that non-stomatal limitation reduces the net photosynthesis rate in a weak-light environment. Shade-tolerant cultivars (MM-51 and CM-39) adapted to low-light conditions via a higher leaf area of flag leaves, light interception rate, and chlorophyll a and b contents; this increased non-structural carbohydrates and sucrose contents in developing grains, ultimately decreasing yield loss by shade stress. Pre-anthesis shading resulted in a greater yield loss than post-anthesis shading because of decreased plant biomass, grain number per spike and 1,000-kernel weight. This study indicates that Rubisco-mediated non-stomatal limitation reduces PN and sucrose content in plants exposed to low-light stress, contributing to decreased grain yield. Our study provides information on the mechanism underlying shade stress tolerance, which will help design future strategies for reducing yield loss in the context of global dimming.

    Keywords: shade stress, shade tolerance, leaf carboxylation efficiency, sucrose metabolism, grain yield

    Received: 17 Jul 2024; Accepted: 12 Nov 2024.

    Copyright: © 2024 Li, Zhao, Ma, Pu, Huang, YANG and Fan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Hongkun YANG, Sichuan Agricultural University, Ya'an, China
    Gaoqiong Fan, Sichuan Agricultural University, Ya'an, China

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