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High Night Temperature Stress on Rice - Insights from Phenomics to Physiology. A Review

Awais Riaz, Julie Thomas, Hafiz Haider Ali, Muhammad Zaheer , Naushad Ahmad, Andy Pereira

Abstract

Rice (Oryza sativa L.), a vital global staple, faces challenges to yield and quality are escalating due to urbanization, deforestation, and climate change, exacerbated by factors like high night temperature (HNT). This comprehensive review explores the multifaceted impacts of HNT on rice, covering physiological, molecular, and agronomic aspects. The rise in minimum temperature, a result of anthropogenic and natural factors, threatens a potential 41% reduction in rice yield by 2100. HNT disrupts growth stages, causing issues such as reduced seed germination, biomass, spikelet sterility, and poor grain development. Recent findings indicate a 4.4% yield decline for every 1°C increase beyond 27°C, with japonica ecotypes exhibiting higher sensitivity than indica. The intricate relationships between elevated CO2, nitrogen regimes, and HNT are examined, revealing the complexity of balancing positive CO2 effects on biomass with HNT challenges. Nitrogen enrichment proves crucial during the vegetative stage but faces reproductive stage hurdles, affecting grain yield and starch synthesis. Additionally, the review elucidates the impact of HNT on plant respiration, emphasizing mitochondrial respiration, photorespiration, and antioxidant responses. Genomic techniques, including CRISPR-Cas9, offer potential for manipulating genes for HNT tolerance. Plant hormones and carbohydrate enzymatic activities are explored, revealing their intricate roles in spikelet fertility, grain size, and starch metabolism under HNT. Despite advancements, gaps in understanding genetic factors influencing heat tolerance and potential trade-offs associated with hormone applications are identified. The importance of interdisciplinary collaboration is underscored, urging a holistic approach for sustainable strategies. Research priorities include elucidating regulatory mechanisms, exploring post-anthesis effects, assessing cumulative HNT exposure, and understanding the interaction between climate variability and HNT impact. This review also provides a foundation for future research to enhance rice resilience in a changing climate.

FP24057  Accepted 12 May 2024

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