The influence of 2,4‐D on ectomycorrhizal symbiosis in pine and spruce seedlings

Abstract In vitro and in vivo investigations with 2,4‐D concentrations showed that mycorrhizal fungi were suppressed particularly by higher concentrations while treated seedlings exhibited quantitative and qualitative deficiency in mycorrhizal development. Short roots became elongated or sometimes remained uninfected. Dichotomous root branching was absent in Pinus sylvestris L. The difference in terms of mycorrhizal impairment was highly significant (P = 0.01). Practical consequences are discussed.