The Effects of Different Exogenous Enhancers on Maize Growth and Their Mechanisms

¹ Research Group, Chinese Academy of Agricultural Sciences, No.12, Zhongguancun South Street, Haidian District, Beijing, China
² Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China

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Abstract

This study examined the impact of chitooligosaccharides (COS) and poly-γ-glutamic acid (γ- PGA) as fertilizer synergists at varying concentrations on the growth and physiological attributes of maize. The goal was to give them a theoretical basis for use in farming. We did a pot experiment with four treatments: chemical fertilizer only (F, control), F with 0.5% COS (FK1), F with 1% COS (FK2), and F with 0.5% γ-PGA (FJ). We measured the growth of maize, the activities of antioxidant enzymes in its leaves, and the diversity of microbes in the soil around its roots. Notably, the 1% COS treatments exhibited the superior performance, increasing plant biomass by 102.9%, phosphorus accumulation by 83.0%, potassium accumulation by 93.8%, and APX activity by 42.4%. The sequencing method revealed that these treatments reshaped the rhizosphere bacterial community by increasing the diversity and abundance of beneficial bacteria. Random Forest regression analysis found that the abundance of phylum Bacillota is the best biomarker for predicting changes in maize biomass. In conclusion, adding COS and γ-PGA to chemical fertilizers made maize grow faster, absorb more nutrients, and have more antioxidant enzyme activity. It also changed the makeup of the rhizosphere bacterial community. Among the treatments, 1% COS showed the best improvement on maize growth. These findings provide a theoretical basis for developing eco- friendly fertilizer formulations that improve nutrient use efficiency and potentially reduce chemical inputs in sustainable agriculture.