Bioassociative effect of cold tolerant Pseudomonas spp. and Rhizobium leguminosarum-PR1 on iron acquisition, nutrient uptake and growth of lentil (Lens culinaris L.)

Abstract

The aim of this study was to access the bioassociative effect of two rhizospheric Pseudomonas spp. with effective root nodulating symbiotic nitrogen fixer Rhizobium leguminosarum-PR1 on plant growth and nutrients uptake of lentil (Lens culinaris L.) plant under greenhouse conditions. Lentil seeds of variety VL Masoor 507 were inoculated with two cold tolerant Pseudomonas sp. strains (NARs1, PGERs17) and R. leguminosarum-PR1, individually or in combination, and were grown in pots using nonsterile sandy loam Entisol. Inoculation with Pseudomonas sp. strain PGERs17 exhibits more vigorous vegetative growth with increase in nodulation (55.0%), leghaemoglobin content (27.7%), physiologically available iron (24.1%), total iron (90.7%) chlorophyll content (43.9%), P uptake (37.1%) and N uptake (27.1%) over R. leguminosarum-PR1 alone at 60 days after sowing (DAS). Coinoculation of Pseudomonas sp. strain NARs1 with R. leguminosarum-PR1 recorded maximum increase in the nodulation 27.5, leghaemoglobin content-45.9, total iron-115.7, total chlorophyll content-21.3, N uptake-52.1 and P uptake-88.9% over R. leguminosarum-PR1 alone at 60 DAS, which suggest that a strong selective synergistic relationship existed between cold tolerant Pseudomonas sp. strain NARs1 and R. leguminosarum-PR1. The variations in efficacy of different treatment combinations indicate the specificity of the inoculation response. These results provide a basis for the selection of an appropriate combination of specific Pseudomonas sp. and R. leguminosarum which could further be utilized for verifying the symbiotic effectiveness and competitive ability of microsymbionts under field condition of hill agro ecosystem.