Seaweed Oligosaccharide Synergistic Silicate Improves the Resistance of Rice Plants to Lodging Stress under High Nitrogen Level

Abstract

The objective of this study was to determine the effect of seaweed oligosaccharide synergistic silicate (Si) fertilizer (SOSSiF) on rice resistance to lodging stress. The results showed that a spraying SOSSiF decreased apparent lodging index and enhanced rice yield significantly under a high N level. The spraying test indicated that the apparent lodging rate of rice was the lowest when SOSSiF was sprayed for four times, and the dosage was 45 kg/ha each time. Morphological and anatomical analysis indicated that SOSSiF decreased plant height and the lower internode length of ZCSM and increased culm cross-sectional area and wall thickness of JNSM significantly compared with the control. Furthermore, SOSSiF enhanced bending strength of rice culm by 38.8% to 63.6%, and reduced lodging index by 36.8% to 42.6%. Chemical component analysis found that SOSSiF elevated the contents of soluble sugar, cellulose, Si, and lignin in the culms of ZCSM and JNSM. Correlation analysis revealed that the lodging index was positively correlated with the length of the lower internode, and was negatively correlated with culm bending strength and culm thickness. The above results suggested that spraying SOSSiF elevates culm contents of Si and lignin and enhances bending strength, thus improving rice lodging resistance and production.