Field application of microbial inoculants improved crop foliar morphology and physiology performance: A global meta-analysis

Abstract

Leaf growth and function play fundamental role for crop development and production. The introduction of functional microbial strains also known as, microbial inoculants (MI) represents promising strategy for enhancing crop vigor and resilience. To obtain a comprehensive understanding of the impact of the MI technique on foliar morphology and physiological performance, a meta-analysis encompassing 168 published articles, comprising of total 1656 paired observations, was conducted. The findings showed that MI amendments resulted in notable enhancements in several key parameters. Specifically the leaf area, leaf area index, and leaf nitrogen content exhibited increases of 16.56 %, 16.28 %, and 13.76 %, respectively. Moreover, the MI-treated crops demonstrated higher values in terms of chlorophyll content, leaf gas exchange indices, and chlorophyll fluorescence parameters suggesting improvements in the MI treatment indicated that light harvesting and utilization by the crops were improved. Additionally, the linear mixed-effects model showed that changes in these parameters (except for intercellular CO2 concentration) after MI addition had a positive effect on crop yield. Upregulated antioxidant enzyme activities, such as POD, CAT, and SOD, in crop leaves increased by 20.91 %, 12.68 %, and 23.08 %, respectively, whereas H2O2 content decreased significantly, by 38.46 %. These results indicate that MI amendment is a promising strategy for improvement of light interception and utilization in crops. MI treatment is expected to increase crop tolerance to stress, thus increasing productivity and yield. Therefore, future adoption of the MI technique could contribute to ensuring food security and agricultural sustainability, however, the factors affecting MI efficacy should be further clarified.