Effects of Molybdenum on Cell Wall Component of Wheat Leaf Under Different Growth Stages

This study was conducted to investigate the potential effects of molybdenum (Mo) on cell wall components in both cultivars of winter wheat (Triticum aestivum L.) by using a pot experiment with two Mo levels (0 and 0.15 mg kg−1) at different growth stages. The leaves were sampled at the stages of tillering, jointing, heading, and milky in winter wheat. The results indicated that the contents of cell wall components changed with the stages of wheat growth to adapt to environmental changes, particularly before the stages of heading, the contents of lignin, cellulose, hemicellulose, and protopectin increased with the stages of wheat growth. Mo application markedly increased cellulose contents by 7.60% at the milky stage in a cultivar of 97014. Mo supply dramatically enhanced hemicelluloses contents by 26.93% and 55.41% at tillering and heading stages in a cultivar of 97003 and by 29.16% and 21.43% at jointing and heading stages in a cultivar of 97014, respectively. Mo supply significantly increased protopectin contents by 78.04%, 108.71%, and 40.62% in a cultivar of 97003 and by 89.70%, 97.03%, and 31.53% in a cultivar of 97014 at tillering, jointing, and heading stages. The increased contents of cell wall components will contribute to improving mechanical strength of leaves. However, the decreased contents of hemicelluloses, soluble pectin by Mo supply were observed at milky stages in wheat. The ratios of soluble pectin to protopectin were decreased by Mo application, confirmed by the decreased activities of pectin methylesterase (PME) in both cultivars of wheat at jointing and milky stages, suggesting that Mo inhibited the conversion of protopectin to soluble pectin by inhibiting PME activity. Overall, the components of the cell wall were affected by Mo, mainly affected the contents of hemicellulose, soluble pectin, and protopectin.