Growth of Pinus arizonica Engelm. plants inoculated with Pisolithus tinctorius and Astraeus hygrometricus under greenhouse conditions

Introduction: Ectomycorrhizal associations are an essential component of nutrient cycling and forest health.Objective: To evaluate the effects of spore inoculation of Pisolithus tinctorius (Pers.) Coker & Couch and Astraeus hygrometricus (Pers.) Morgan on Pinus arizonica Engelm. growth.Materials and methods: Three mycorrhizal inoculation treatments (A. hygrometricus, P. tinctorius and Ectorrize®) were applied with three volumes (10, 25 and 50 mL: 106 spores∙mL-1) and a control group with no inoculum. The variables measured were mycorrhizal survival and colonization; plant height; shoot length and diameter; root length and biomass. The ectomycorrhizas were characterized and a mineral analysis of nutritional elements in the shoot and root was performed. The effects of fungal species and inoculum volume were determined by randomized ANOVA (α = 0.05).Results and discussion: The volume of this inoculum had no significant effect (P > 0.05) on the variables, but there were differences between the fungal species and the control (P > 0.05); with P. tinctorius having the greatest significant effect. Inoculated plants had higher survival rate and higher amount of minerals in the composition compared to non-inoculated plants (P > 0.05). The ectomycorrhizas showed clear morphological differences; the Hartig net was observed as an indicator.Conclusion: Inoculation with the ectomycorrhizal fungi improved the morphological development of P. arizonica. The smallest inoculum dose (10 mL: 106 spores∙mL-1) is recommended, mainly of the fungus P. tinctorius.