Low‐temperature stress during the flowering period alters the source–sink relationship and grain quality in field‐grown late‐season rice

Abstract

Late‐season rice, a major contributor to the production of high‐quality rice in China, often experiences low temperatures during the flowering period. The objective of this study was to determine the effect of low temperature stress on grain quality and to identify related physiological factors in late‐season rice. Sink and source characteristics and grain quality traits of two high‐quality late‐season rice cultivars were compared between a year in which low temperatures occurred during the flowering period (2020) and a normal year (2019) under field conditions. Low temperatures during the flowering period in 2020 resulted in a reduction in spikelet filling and consequent increases in source–sink ratios and grain weight and N content compared to 2019. The head rice rate and protein content of the milled rice were increased in 2020 compared to 2019. Starch gel consistency and peak, trough, breakdown, final, and consistency viscosities were reduced while setback viscosity, paste temperature, and texture properties (hardness, springiness, cohesiveness, resilience, and chewiness) were increased for milled rice (or milled rice flour or cooked milled rice) in 2020 compared to 2019. The glucose production rate and total glucose production from in vitro digestion of cooked milled rice was reduced in 2020 compared to 2019. The results of this study suggest that low temperature stress during the flowering period can improve milling, nutritional, and health qualities but reduce the cooking and eating quality in late‐season rice by altering the source–sink relationship.

Extreme Low-Temperature Stress Affects Nutritional Quality of Amino Acids in Rice

“…Our previous results with this same experiment showed that LTS after flowering did not significantly decrease grain weight, except under D3T4 treatment in Nanjing 46 ( Ali et al, 2021 ). And this result was similar to the previous studies ( Huang et al, 2021 ; Shi et al, 2021 ). Therefore, we assume that the main reason for the dilution effect of the amino acids content could be the decreasing grain number due to reduced seed-setting rate under LTS, as reported in our previous study ( Ali et al, 2021 ), and the decreasing grain number under LTS could significantly reduce the sink capacity.…”

“…LTS has been shown to affect the content of several nutrient in rice grains ( Jia et al, 2015b ; Huang et al, 2021 ). There were several possible reasons for LTS effects on content of amino acids.…”

Texture and digestion properties of hybrid rice: A comparison between two cultivars released 18 years apart

“…About 100 mg samples of the cooked rice were subjected to in vitro digestion to determine the amount of glucose produced per unit fresh weight at six digestion times (15, 60, 120, 180, 240, and 300 min) using a Glycemic Index Analyzer (NutriScan GI20; Next Instruments, Condell Park, NSW, Australia). The starch digestion process of the cooked rice (i.e., the change in the amount of glucose produced over time) was fitted to the exponential association model for calculating starch digestion parameters, including active digestion duration, total glucose production, and glucose production rate ( Huang et al, 2021 ).…”

Effects of post-silking low temperature on the starch and protein metabolism, endogenous hormone contents, and quality of grains in waxy maize

“…Low temperature (LT) is an important abiotic stress that seriously affects the production and development of global cereal crops (Huang et al, 2021;Zhang et al, 2021). Several studies have found that the post-silking/grain filling stage is very sensitive to LT during the growth cycle of cereal crops (Thakur et al, 2010;Luo, 2011).…”

“…Starch and protein are important components in grains, and the dynamics of their content and accumulation determines the yield of cereal crops (Lu et al, 2014a;Huang et al, 2021;Zhang et al, 2021). In cereal grains, starch and protein biosynthesis is a complex process determined by the coordinated action of enzymes (Marschner, 2011;Ran et al, 2020).…”