Microbial-assisted Salinity Stress Alleviation in Acid Lime (Citrus aurantifolia Swingle)

Abstract

Soil salinity is a major abiotic stress limiting citrus productivity, particularly in acid lime (Citrus aurantiifolia Swingle), which is moderately sensitive to salt stress. Microbial inoculants, especially plant growth-promoting rhizobacteria (PGPR), have emerged as eco-friendly tools to alleviate salt-induced damage by enhancing nutrient uptake and osmotic adjustment. This study evaluates the efficacy of selected microbial inoculants, including Pseudomonas fluorescens, Bacillus subtilis, and Trichoderma viride in mitigating the effects of salinity (3 dS m-1 and 6 dS m-1 EC) on acid lime seedlings under controlled conditions. Key physiological parameters such as shoot, root, root/shoot, seedling length, germination percentage, seedling vigour index 1, root-shoot ratio were assessed. Microbial inoculants successfully improved the shoot length under severe stress. P. fluorescens showed the highest shoot length (4.78 cm), followed by B. subtilis (4.56 cm) and T. viride (4.46 cm) at 6 dS/m, while non-inoculated plants had least shoot length (3.22 cm). The balanced growth was observed in B. subtilis inoculated plants, leading to least root/shoot (2.09). On the other hand, plants with no microbial inoculants faced higher stress causing highest root/shoot (3.56). Germination rate was also highly influenced by microbes, especially T. viride. When only 32% plants were generated in control treatment, 52% germination was occurred in T. viride treated plants. So, these inoculants led to ultimately higher seed vigour index 1. These finding support the potential of microbial inoculants as sustainable solutions for managing salt stress in acid lime cultivation. The findings support the potential of microbial inoculants as sustainable solutions for managing salt stress in acid lime cultivation.