Effect of exo-polysaccharides producing bacterial inoculation on growth of roots of wheat (Triticum aestivum L.) plants grown in a salt-affected soil

Abstract

Effect of soil salinity on physico-chemical and biological properties renders the salt-affected soils unsuitable for soil microbial processes and growth of the crop plants. Soil aggregation around roots of the plants is a function of the bacterial exo-polysaccharides (EPS), however, such a role of the EPS-producing bacteria in the saline environments has rarely been investigated. Pot experiments were conducted to observe the effects of inoculating six strains of EPS-producing bacteria on growth of primary (seminal) roots and its relationship with saccharides, cations (Ca 2+ , Na + , K + ) contents and mass of rhizosheath soils of roots of the wheat plants grown in a salt-affected soil. A strong positive relationship of RS with different root growth parameters indicated that an integrated influence of various biotic and abiotic RS factors would have controlled and promoted growth of roots of the inoculated wheat plants. The increase in root growth in turn could help inoculated wheat plants to withstand the negative effects of soil salinity through an enhanced soil water uptake, a restricted Na + influx in the plants and the accelerated soil microbial process involved in cycling and availability of the soil nutrients to the plants. It was concluded that inoculation of the EPS-producing would be a valuable tool for amelioration and increasing crop productivity of the salt-affected soils.

Selection of Hyper Exopolysaccharide Producing and Cyst Forming Azotobacter Isolates for Better Survival under Stress Conditions

“…Similar results were obtained for wheat plants inoculated with either Azotobacter or Azospirillum (Ashraf et al, 2006). This significant increase in root adhering soil mass around the roots of rice plants inoculated with Azotobacter isolate AzRDM2 could be the result of either an increase in soil adhesion to roots or a higher soil aggregate stability around roots, or both.…”

Effect of Exopolysaccharide-Producing Bacteria and Melatonin on Faba Bean Production in Saline and Non-Saline Soil

“…The obtained results indicate that the beneficial effects of inoculation are more pronounced for the average 100-seed weight and seed yield (ha −1 ) in plants grown in saline soil than those grown in non-saline soil. Similarly, Ashraf et al [35] concluded that the inoculation of EPS-producing bacteria is a valuable tool for ameliorating and increasing crop productivity under salinity stress. In this respect, Qurashi and Sabri [36] reported that inoculation with EPS-producing bacteria at a higher salt stress up to 100 mM increased soil aggregation, which was more pronounced around roots, while aggregates formed by exopolysaccharides favored plant growth under salt stress.…”

Application of Halotolerant Bacteria to Restore Plant Growth Under Salt Stress

“…In this experiment, the P, K and N concentrations were increased in lettuce plants; in contrast, Na + was decreased. Some observations revealed that the capacity of bacteria to mitigate salt stress is due to the production of polysaccharides binding Na + in the root zone (Ashraf et al 2006 ;Awad et al 2012 ). Sarathambal and Ilamurugu ( 2013 ) showed the detailed PGP-features of some salt-tolerant diazotrophic PGPR, which were used to restore growth of paddy under saline conditions.…”