Structural and functional properties of indica rice starch as influenced by late-stage nitrogen fertilization

ABSTRACT

Late-stage nitrogen (N) fertilization is an important crop management for improving rice production and also affects the quality of rice, whereas information on the influence of late N on structural and functional properties of indica rice starch is lacking. In this study, effects of various N rates (0, 60, and 120 kg ha⁻¹ referred to as N₀, N₆₀ and N₁₂₀, respectively) on structural and functional properties of grain starches from two rice cultivars (OM052 and Chaoyou1000) were investigated. Comparison of different N treatments showed that late N application exhibited strong influence on starch properties, and the sensitivity to N application varied with rice genotypes. Compared to non N rate, higher input of N (N₆₀ for OM052, and N₁₂₀ for Chaoyou1000) significantly reduced apparent amylose content (AAC), relative crystallinity (RC), gelatinization enthalpy, swelling power, solubility and degree of hydrolysis, but significantly increased the proportion of short chains with degree of polymerization 6–12 in amylopectin and gelatinization onset temperature. Further comparison and principal component analyses revealed that the variations in the starch functional properties were due mainly to the changes in RC. The solubility was positively associated with AAC. The present results can provide important information for understanding the environmental regulation of starch biosynthesis in rice grain.

KEYWORDS:

• Rice
• nitrogen
• crystalline structure
• starch molecular structure
• functional properties

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This research was funded by grants from the National Key R&D Program, China [2017YFD0301305, 2017YFD0300106]; the Program of Rice Genetic Breeding Key Laboratory of Guangxi province, China [2018-15-Z06-KF15]; and the Major Science and Technology Program of Anhui province, China [201903a06020012].