Maize (Zea Mays L.) Growth and Metabolic Dynamics with Plant Growth- Promoting Rhizobacteria under Salt Stress

Abstract

Maize (Zea mays L.) biomass and its allied attributes were assessed under salinity stress and three plant growthpromoting rhizobacteria (Pseudomonas fluorescens, Pseudomonas putida and Azotobacter vinelandii) treatments. The three PGPRs inocula exhibited a different pattern of shoot growth under both normal and saline stress conditions. Plant biomass, carbohydrates, protein and chlorophyll content were reduced by saline stress, however application of PGPRs treatments improved them either in comparison to control samples or to untreated samples under saline stress. Lipids and antioxidant enzymes (catalase and peroxidase) increased as a response for saline stress as an indication of oxidative stress. Plant growth-promoting rhizobacteria treatment restored them to semi-normal levels. Sodium/ potassium balance was observed to be disturbed by saline stress through higher levels of Na+ and lower levels of K+, but treating samples balance was clearly restored close to normal conditions especially in the root system.