Biofertilizers Alleviate Salinity Stress in Medicinally Important Plant - Catharanthus roseus (L.) G. Don by Enhancing Morphological and Photosynthetic Attributes

Abstract

Salinity stress is the major growth limiting factor in most economically important crops as it adversely declines the yield and productivity of plants. Catharanthus roseus is an essential medicinal plant for the drug industry, and its productivity is highly affected by salt stress. The present study investigated the potential role of plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungal (AMF) consortium in alleviating salinity stress in C. roseus. The study analyzed growth parameters and photosynthetic attributes (chlorophyll pigment and gas exchange parameters) in salinity stress conditions and with the application of PGPB. C. roseus showed a significant decline in shoot height, root height, fresh weight, dry weight, specific leaf area, and relative water content by 17.79%, 36.80%, 17.90%, 65.55%, 48.35%, and 43.29%, respectively, under salinity stress. However, mycorrhizal inoculation improved plant growth by 35.57%, 36.60%, 44.51%, 231.48%, 22.87%, and 18.50%, respectively. Electrolytic leakage increased by 45.09% under salinity stress but in contrast, it is decreased by 17.02% under mycorrhizal inoculation as compare to control treatment. Photosynthetic attributes viz. photosynthetic rate (Pn), stomatal conductance (C), and transpiration rate (E) also showed a significant decline in salinity treatment by 42.57%, 51.96%, and 31.98%, respectively, as compared to control treatment. In comparison, mycorrhizal inoculation increased photosynthetic attributes by 225.13%, 204.72%, and 159.51%, respectively. The present research suggested that phosphate solubilizing bacteria and mycorrhizal application play the most effective role in inducing salinity stress tolerance in C. roseus and, therefore, can be considered a cost-effective and sustainable approach to provide tolerance against salinity stress.