ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Photosynthesis and Photobiology
Volume 16 - 2025 | doi: 10.3389/fpls.2025.1648079
This article is part of the Research TopicPhotosynthesis under Variable Environmental ConditionsView all 7 articles
The adaptability of soybean photosynthesis to midday high-light duration through CEF-NPQ coupling regulation
Provisionally accepted
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
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Fluctuating light (FL) conditions particularly the diurnal alternation between shaded and high-light periods are intrinsic to intercropping systems and impose substantial regulatory challenges on crop photosynthesis. However, the cultivar-specific mechanisms underlying adaptation to such dynamic light environments remain largely unexplored. Here, we examined how the duration of midday highlight exposure modulates the coordination between cyclic electron flow (CEF) and non-photochemical quenching (NPQ) in two soybean cultivars grown under simulated intercropping light regimes. Plants were exposed to morning shade followed by either short (T30) or prolonged (T150, T200) midday high-light treatments. All treatments triggered common photoprotective responses, including increased energy dissipation (DIo/CSm, +18.7-22.3%) and reduced electron transport efficiency (ETo/CSm, -14.2-17.5%). Yet, the cultivars exhibited distinct photoregulatory strategies depending on light duration. The light-adapted cultivar ND12 rapidly established a proton gradient (ΔpH; 34.8% faster) and sustained higher PSII efficiency (ETRII, +41.5%) under brief high-light exposure, indicating a preemptive ΔpH priming mechanism. In contrast, the light-sensitive GX7 required extended high-light duration (T200) to induce CEF (+60.5%) and plastoquinone pool expansion (+22.0%), suggesting a delayed, duration-dependent adjustment strategy. These cultivar-specific responses ultimately enhanced photosynthetic performance by 34.8-52.4% under FL conditions. Our findings offer mechanistic insights into how midday light duration shapes genotype-dependent photosynthetic regulation, providing a physiological basis for optimizing light utilization in intercropping systems.
Keywords: intercropping, Photosynthesis, Photoprotection, cyclic electron flow, Light density
Received: 16 Jun 2025; Accepted: 05 Aug 2025.
Copyright: © 2025 Lei, Wu, Gao, Wang, Wang, Diwakar, Tan, Yang and Yang. 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: Feng Yang, College of Agronomy, Sichuan Agricultural University, Chengdu, China
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