The impact of co-inoculation with rhizobacteria and organic wastes on enhancing the plant growth and nutrient uptake in Zea mays L.

BACKGROUND AND OBJECTIVESZea mays L. is the leading cereal and fodder crop that is used for the production and consumption of food items. Synthetic fertilizers are used in conventional agriculture systems to obtain a high maize crop yield. But the frequent application of synthetic fertilizers causes deleterious effects on humans as well as excessive utilization of these fertilizers reduces plant nutrient uptake and soil fertility. PGPR together with organic waste could increase nutrient absorption and plant growth parameters. In this research, two rhizobacterial strains.MATERIALS AND METHODSBacillus cereus and Pseudomonas putida were isolated, molecularly characterized, and amplified by using ۱۶s RNA primer and several biochemical tests were performed. A seed germination bioassay was performed to study the impact of PGPR on maize seed growth. Similarly, a pot experiment was executed to investigate the impact of B. cereus, P. putida, consortia (individually (۳mL) and together with organic manure ۵۰% V/V of CD (Cow dung) and VC (Vermicompost) on enhancing the plant growth petameters and nutrient uptake enhancement.RESULTS AND DISCUSSIONRB-۱ strain was tested positive for HCN production, Catalase test, Oxidase test, while on the other hand it was tested negative for fluorescent test, (KOH) solubility test, levan production Test, carbohydrate fermentation test, (H۲S) production test as well as for oxidative fermentative test. Similarly, RB-۲ strains tested positive for all the tests except carbohydrate fermentation. Both strains were tested positive for IAA production (۱۷.۰۵ - ۲۰.۹۰ mg mL-۱), phosphate solubilization (۷۵-۸۱ mg mL-۱) as well as for siderophore production (۲۴.۵۳-۲۸.۵۵ %). Both strains, RB-۱ identified as Bacillus cereus (MG۰۲۷۶۳۳.۱) while RB-۲ identified as Pseudomonas putida (MF۴۶۲۹۰۳-۱). both rhizobacterial strains and bacterial consortia (Sphingobacterium pakistanensis sp., Pantoea sp., Cellulomonas pakistanensis., Citrobacter sp., Exiguobacterium sp., Raoultella sp., Acinetobacter sp., Enterobacter sp., Alcaligenes pakistanensis) showed positive results compared to control. All treatments showed maximum growth rate, biomass production, chlorophyll a and b, and carotenoid content, growth parameters and nutrient uptake ability in maize. The results showed that RB-۱, RB-۲, and consortia with the combination of CD and VC significantly (P < ۰.۰۵) increased NPK, Mg, and Fe in shoot and root respectively compared to individual treatments as well as positive and negative control treatments.CONCLUSIONNew combination with different organic waste manure with PGPR could give tremendously positive results for sustainable agriculture.

کلیدواژه ها:

PGPR ، molecular and biochemical characterization ، phylogenetic tree ، Zea mays ، nutrient Uptake ، NPK