Growth response and nutrient uptake of blue pine (Pinus wallichiana) seedlings inoculated with rhizosphere microorganisms under temperate nursery conditions

Abstract

Microbial inoculants (Trichoderma harzianum, Pseudomonas fluorescens, Laccaria laccata) inoculated either individually or in combination significantly improved the growth and biomass of blue pine seedlings. The ECM fungus Laccaria laccata, when inoculated individually, showed significantly higher plant growth, followed by Pseudomonas fluorescens and Trichoderma harzianum. The combined inoculation of rhizosphere microorganisms showed synergistic growth promoting action and proved superior in enhancing the growth of blue pine than individual inoculation. Co-inoculation of L. laccatawith P. fluorescens resulted in higher ectomycorrhizal root colonization. Uptake of nutrients (N, P, K) was significantly improved by microbial inoculants, tested individually or in combination. Combined inoculation of L. laccata with T. harzianum and P. fluorescens significantly increased in N, P and K contents in blue pine seedlings as compared to control. Acid phosphatase activity in the rhizosphere of blue pine seedlings was also enhanced by these microorganisms. L. laccata exhibited higher acid phosphatase activity followed by P. fluorescens.