ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Crop and Product Physiology
Volume 16 - 2025 | doi: 10.3389/fpls.2025.1660130
Transpirational cooling enhances grain yield and quality in heat-tolerant rice varieties
Provisionally accepted
- Yangtze University, Jingzhou, China
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High temperatures during the grain-filling stage in rice often lead to a shortened grain-filling duration and accelerated maturity, typically resulting in reduced grain yield and quality. Leaf evaporative cooling via transpiration has been identified as an important adaptive mechanism for heat stress in rice. However, its relevance for evaluating varietal tolerance to heat during grain filling remains unclear. In this study, we assessed 28 newly bred high-quality rice varieties to examine the extent and genotypic variation in transpirational cooling and its effects on grain yield and quality under a staggered sowing system (S1 and S2). Our results showed that high temperatures significantly decreased 1000-grain weight by 1.6 g and head rice rate by 6.7%, while increasing chalkiness by 3.3%. Cluster analysis grouped the varieties into three categories of heat tolerance: tolerant, intermediate, and susceptible. Under heat stress, heat-tolerant varieties maintained significantly lower leaf and panicle temperatures and exhibited higher stomatal conductance than heat-susceptible ones during grain filling. These tolerant varieties also possessed higher stomatal density and total stomatal area. Furthermore, the change in 1000-grain weight was negatively correlated with stomatal density, while the change in head rice rate showed a negative correlation with stomatal size. These findings suggest that varietal differences in heat tolerance during grain filling may parallel those observed at anthesis. Stomatal regulation of the canopy microenvironment may serve as a general physiological basis for varietal heat response in rice.
Keywords: Heat stress, grain filling, stomata, Head rice rate, Grain weight
Received: 05 Jul 2025; Accepted: 08 Sep 2025.
Copyright: © 2025 Mu, Wang, Gao, Liu and Okpala. 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: Qilin Mu, Yangtze University, Jingzhou, China
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