Abstract:

【Objective】 Accumulations of high molecular weight glutenin subunits (HMW-GS) and glutenin macropolymer (GMP) play key roles in determining grain quality in wheat (Triticum aestivum L.). Two wheat cultivars owning the same HMW-GS type (7+8 and 2+12) were selected to study the effects of shading from jointing to maturity on HMW-GS accumulation and GMP content in grain. 【Method】 HMW-GS was firstly separated using the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and each HMW-GS subunit band in the gel was cut and extracted. Content of each HMW-GS subunit was then quantified by colorimetric analysis of the HMW-GS subunit extraction. 【Result】 Shading from jointing and maturity promoted the initial formation time of HMW-GS. The severe shading treatments (18% and 25%) shortened the rapid accumulation period of HMW-GS and reduced the accumulating rate of total HMW-GS during late grain filling period. Thus, the accumulation amount of total HMW-GS at maturity was lower under these treatments than the non-shading treatment. However, contents of HMW-GS and GMP were higher under severe shading than the control. A low-degree shading treatment (10%) prolonged the rapid accumulation period of HMW-GS, and increased the final accumulation amount and content of total HMW-GSP. 【Conclusion】 Shading from jointing to maturity obviously affected the accumulation amounts and contents of total HMW-GS in wheat grain. However, this regulatory effect was related to shading intensity.

Key words: wheat, shading, high molecular weight glutenin subunits (HMW-GS), glutenin macropolymer (GMP)