Split Application of Potassium Reduces Rice Chalkiness by Regulating Starch Accumulation Process Under High Temperatures
Chalkiness in rice is adversely affected by high temperatures during the flowering and grain-filling stages. Potassium (K) is essential for improving grain quality and heat resilience. The effects of split application K fertilizer on rice chalkiness under high temperatures during the flowering and g...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Agronomy |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4395/15/1/116 |
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| Summary: | Chalkiness in rice is adversely affected by high temperatures during the flowering and grain-filling stages. Potassium (K) is essential for improving grain quality and heat resilience. The effects of split application K fertilizer on rice chalkiness under high temperatures during the flowering and grain-filling stages were investigated in this study. Four treatments, including ambient temperatures with basal K fertilizer (AT-K1), high temperatures with basal K fertilizer (HT-K1), high temperatures with 70% K pre-transplanting and 30% K at the heading stage (HT-K2), and high temperatures with 30% K pre-transplanting and 70% K at the heading stage (HT-K3), were conducted. The results revealed that the chalky grain rate and chalkiness degree were reduced by 9.2–13.72% and 12.16–19.91%, respectively, by the split application of K fertilizer through effectively modulating the sucrose-to-starch conversion process in the rice grains, relative to the single basal application of K fertilizer under high temperatures. Specifically, the split application of K fertilizer reduced the enzymatic activities of SuSy, ADPGase, and SBE by 3.17–34.20% at 5–10 DAA, and GBSS and SSS by 6.48–13.50% at 5 DAA, but enhanced them by 5.50–54.90% from 15 DAA and 2.07–97.10% from 10 DAA. Similarly, the gene expression levels of enzymes involved in this process were decreased by 3.52–24.12% at 5 DAA but increased by 8.61–30.00% at 20 DAA by the split application of K fertilizer. This modulation led to a retardation in the excessive accumulation of starch during the early grain-filling stage but a higher starch accumulation rate during the middle and later stages, combined with a longer duration of starch accumulation, ultimately resulting in higher starch accumulation and reduced rice chalkiness. These results suggest that the application of K fertilizer during the heading stage is effective in compensating the deterioration of rice chalkiness by high temperatures. |
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| ISSN: | 2073-4395 |