Growth enhancement in containerized Pinus gerardiana seedlings inoculated with ectomycorrhizal fungi

Mycorrhizal fungi boost host plant growth by improving roots' ability to absorb nutrients and water from the rhizosphere soil. In this study, a mass inoculum of the ectomycorrhizal fungus Scleroderma polyrhizum was produced on wheat grains and incorporated into polybags during seed sowing of Pinus gerardiana, with the expectation that the roots of the germinating seedlings would form a mycorrhizal association with S. polyrhizum. For 2 years, the seedlings' growth parameters were measured at 3-month intervals. The seedlings raised in inoculated bags exhibited ectomycorrhizal anatomy and higher growth indices like absolute growth rate, relative growth rate, sturdiness quotient, volume index, quality index etc. The growth parameters of 2-year-old inoculated seedlings were 44.36 to 94.36 percent higher than control. Shoot dry weight increased the most (94.36 percent), followed by root volume (93.59 percent), shoot fresh weight (91.42 percent), root fresh weight (79.46 percent), and collar diameter increased the least (49.30 percent). Two-year-old seedlings were outplanted in two locations: one within and one beyond its normal zone of occurrence. Inoculated seedlings fared better at both sites in terms of survival and growth. S. polyrhizum inoculation has accelerated the growth metrics of P. gerardiana seedlings. Thus, it can be recommended that the P. gerardiana nursery should be raised by artificial inoculation with S. polyrhizum to produce healthy, tall planting stock in a shorter nursery time while also lowering maintenance costs.

Automated summary

Inoculation of the ectomycorrhizal fungus Scleroderma polyrhizum on Pinus gerardiana seedlings improved their growth and survival rates, resulting in healthier and taller planting stock. The inoculated seedlings exhibited higher growth indices and outperformed the control group in terms of growth parameters. This study highlights the importance of artificial inoculation with mycorrhizal fungi for nursery management and production of high-quality seedlings.