Starch morphological, structural, pasting, and thermal properties of waxy maize under different heat stress durations at grain formation stage

Abstract

Heat stress (HS) is a major environmental constraint in sustaining global waxy maize production under future climate condition. Starch physicochemical properties under 5‐day (HS5) and 10‐day (HS10) postsilking HS were investigated using two waxy maize hybrids (Suyunuo5 and Yunuo7) as materials. Ambient and high temperatures were 28°C/20℃ and 35°C/27℃, respectively. Starch granules were enlarged and exhibited additional pitting or cellular structures, increased amylopectin chain length, increased relative crystallinity, and increased 1047/1022 cm−1 ratio under HS. This finding indicated the stable and ordered structure of starch granules, especially under HS10. Pasting viscosities of Yunuo7 reduced by HS, and the change was the same under both HS5 and HS10. Peak viscosity of Suyunuo5 was unaffected and breakdown viscosity increased with HS5 although both characteristics decreased with HS10. HS increased gelatinization temperatures and retrogradation percentage. Results showed that HS enlarges starch granules with stable structure, reduces starch viscosities, and increases retrograde tendency, with severe detrimental effect under long HS durations.

Leaf photosynthetic characteristics of waxy maize in response to different degrees of heat stress during grain filling

“…Each treatment included 50 pots. The soil properties in this study were the same as that previously reported [ 7 ]. In this experiment, seedlings were raised in a seeding tray and then transplanted into a pot.…”

“…Heat stress during grain filling affects the source and sink of maize, resulting in low and unstable grain yield and quality [ 7 , 8 ]. Source capacity is directly affected by the decline in carbohydrate synthesis caused by a decrease in photosynthesis and an increase in respiration rate [ 9 ].…”

Interactive Effects of Nitrogen and Potassium on Grain Yield and Quality of Waxy Maize

“…Waxy maize is a special crop, characterized by a unique structure of starch, which creates enormous possibilities for its application [ 1 ]. Among the various types, waxy maize starch is distinct, with starch composed of nearly pure amylopectin, which provides advantages of viscosity, stability, and retrogradation [ 2 ]. Waxy maize was originally used mainly for industrial production, and only to a small extent for food production [ 3 , 4 ].…”