Cross talk between PGPR and Casuarina junghuhniana on lignite mine soil

Establishment of plant communities through revegetation offers good scope for rehabilitation of degraded ecosystems like post mined land. Seeding the plants with Plant Growth Promoting Rhizobacteria (PGPR) during revegetation process can augment the growth of the plants besides enriching the soil with macro and micronutrients. The present study investigates the ability of PGPR isolates Brevibacillus borstelensis (KY 614550) and Bacillus subtilis (KY 614549) isolated from the mine soil of Neyveli Lignite Corporation India Limited to promote plant growth on mine soil. Seed germination test indicated that the PGPR isolates had a stimulatory effect on Vigna radiata seedlings as evident by significant increase in per cent germination, root length, shoot length and fresh weight over control. PGPR application alone and in combination with organic amendments (Press mud and Farm yard manure at 25% and 50% levels) during pot culture trials resulted in growth promotion of Casuarina junghuhniana saplings (C.N- Australian pine; Family- Casuarinaceae) with apparent increase in shoot length, chlorophyll content, carbohydrate and protein levels. Antioxidant enzyme levels were found to be higher in control plants indicating the efficiency of treatment combinations in combating the biotic and abiotic stress when plants were grown on mine soil. This apparent effect resulting from the seeding of the tree crop with potent PGPR isolates can be translated to develop a healthy soil ecosystem in degraded mined lands.