Effects of sulphur fertilizer on glutenin macropolymer content and particle size distribution in wheat grain

Abstract

Two wheat cultivars (Gaocheng8901 and Yumai50) grown were used to investigate the effect of sulphur fertilizer on the glutenin macropolymer (GMP) size distribution and the contents of glutenin subunits in wheat. The results showed that the contents of GMP, high molecular weight glutenin subunit (HMW-GS) and low molecular weight glutenin subunit (LMW-GS) were improved by sulphur fertilizer under lower nitrogen (N) condition in both cultivars. Under normal N (240 kg N/ha) conditions, sulphur application improved the contents of HMW-GS, LMW-GS and GMP within sulphur rates from 30-60 kg/ha, while decreased when sulphur rate of 90 kg/ha. The volume percentage of GMP particles < 60 μm decreased within sulphur rates from 30-90 kg/ha under lower N treatments. Under normal N condition, the volume percentage of GMP particles > 60 μm increased within the sulphur rates from 30-60 kg/ha, while decreased when excessive sulphur of 90 kg/ha was applied. It is suggested that appropriate sulphur fertilizer was favourable for the formation of large GMP particles, but too much of it was unfavourable under normal nitrogen condition. Sulphur fertilizer did not significantly affect the number distribution of GMP particles in both cultivars. The volume percentage of GMP particles > 60 µm was positively correlated with H/LMW-GS (the ratio of HMW-GS and LMW-GS) and GMP content. It indicated that larger GMP particles had more the ratio of HMW-GS and LMW-GS. And the higher the proportion of larger particles, the higher the content of GMP in wheat grain.

Keywords

• winter wheat (triticum aestivum l.)
• glutenin macropolymer
• nitrogen and sulphur interaction
• size distribution