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

Abstract

Waxy maize has many excellent characteristics in food and nonfood industries. However, post-silking low temperature (LT) has severe limitations on its grain yield and quality. In this study, field and pot trials were conducted to investigate the effects of post-silking LT on the physiological, biochemical, and functional characteristics of two waxy maize grains. The field and pot trials were performed with sowing date and artificial climate chamber, respectively, for LT treatment from silking stage to maturity. Results in pot trial were used to explain and validate the findings in field trial. Compared with the ambient treatment, the LT treatment significantly reduced kernel weight during the grain filling stage (P < 0.05). LT treatment in both environments resulted in an average decrease in dry weight of SYN5 and YN7 at maturity by 36.6% and 42.8%, respectively. Enzymatic activities related to starch and protein biosynthesis decreased under the LT treatment during the filling stage, accompanied by a decrease in the accumulation amounts and contents of soluble sugar and starch, and a decrease in protein accumulation amount. Meanwhile, the contents of abscisic acid, indole-3-acetic acid, and gibberellin 3 in grains decreased under the LT treatment during the filling stage. Peak, trough, breakdown, final, and setback viscosities of grains decreased by LT. LT treatment decreased the gelatinization enthalpy of grains and increased the retrogradation percentage. In conclusion, post-silking LT stress altered the content of grain components by inhibiting the production of phytohormones and down-regulating the enzymatic activities involved in starch and protein metabolism, which resulted in the deterioration of grain pasting and thermal properties.

Relationship between Chalkiness and the Structural and Physicochemical Properties of Rice Starch at Different Nighttime Temperatures during the Early Grain-Filling Stage

“…The proportions of the numbers and surface areas of the starch granules also exhibited an identical trend, with those of the large starch granules reduced by 14.05% and 24.14% in the JXZ variety, respectively, and by 20.27% and 26.25% in the HHZ variety, respectively. Similar results were observed under low temperatures at the GFS, which inhibited the enzymes related to the biosynthesis and accumulation of starch, resulting in an elevation in the number of small and medium-sized starch granules [36,37]. Meantime, the LNT delayed the development of starch granules in the endosperm and inhibited the absorption and accumulation of assimilates, thereby blocking the biosynthesis of large starch granules [19,35].…”

Dynamic monitoring of maize grain quality based on remote sensing data

“…Starch and protein accumulation in maize kernels have been reported to be regulated by water and temperature in previous studies (Singletary et al, 1994;Correndo et al, 2021;Guo et al, 2022). The sucrose required for starch accumulation was regulated by photosynthesis, which was affected by solar radiation, temperature, precipitation, and other meteorological factors.…”