HMW-GS Accumulation and GMP Size Distribution in Grains of Shannong 12 Grown in Different Soil Conditions

To study the accumulation of high-molecular-weight glutenin subunit (HMW-GS) and its relation to glutenin macropolymer (GMP) particle distribution, wheat (Triticum aestivum L.) cultivar Shannong 12 was grown in a pool experiment under 3 soil textures. The sampled spikes were partitioned into superior and inferior grains. The HMW-GS were separated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Fourteen days after anthesis, HMW-GS formed in both superior and inferior grains and its content was higher in superior grain than in inferior grain, showing stronger ability for accumulating HMW-GS in the superior grain. HMW-GS accumulation and GMP content were the highest in clay soil, followed by sandy and loam soils. The diameter of GMP particle ranged from 0.37 to 245 μm. The distributions of GMP volume and surface area showed the pattern of two-peak curve, and the GMP number distributed in the pattern of single-peak curve. For GMP particles that larger than 100 μm in superior grain, the percentages of number and volume were significantly higher than those in inferior grain. Correlation analysis showed that the contents of HMW-GS and GMP were negatively correlated with the volume percentage of GMP particles less than 10 μm and less than 100 μm, and positively correlated with GMP particles larger than 100 μm. The result suggested that larger GMP particles have higher HMW-GS content in wheat grain.