Post-Heading High Nighttime Temperature Impairs Grain Protein-Starch Balance and Rice Quality Through Altering Nitrogen Metabolism.
Liu Z, Xia S, Li Y, Li H, Zhu M
Climate Adaptation
Rice you eat could become chalkier, gummier, and lower quality as nights get warmer — and this research points toward breeding solutions that could protect the taste and texture of one of the world's most important staple foods.
Scientists grew two types of rice under warmer nighttime conditions to mimic climate change. One variety responded by pulling too much nitrogen from its leaves into its grains too quickly, causing a protein buildup that disrupted the grain's normal starch-protein balance. This imbalance made the cooked rice chalkier and changed its texture — showing that not all rice handles heat stress the same way.
Key Findings
Nighttime temperatures raised from 22°C to 27°C significantly increased grain protein content in one rice variety (YY4949) but not the other (HHZ), demonstrating clear genetic differences in heat stress response.
The protein-to-amylose ratio showed a stronger correlation with chalkiness and pasting (cooking texture) characteristics than protein content alone, identifying it as a key quality indicator under heat stress.
Accelerated chloroplast breakdown and upregulated nitrogen transport enzymes in YY4949 drove excessive nitrogen remobilization from leaves to grains, depleting the leaf 'source' and disrupting starch-protein balance in the grain.
chevron_right Technical Summary
Warmer nights caused by climate change reduce rice grain quality by throwing off the balance between protein and starch. A study of two rice varieties found that one accumulated excess protein under high nighttime temperatures, making the rice stickier, chalkier, and less palatable.
Abstract Preview
High nighttime temperatures (HNT) tend to diminish rice quality by disrupting assimilate translocation and grain filling process in rice (Oryza sativa L.). However, there is controversy remains reg...
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