Indole 3-acetic acid production by ectomycorrhizal fungi.

Ability of 8 ectomycorrhizal fungi to synthesise indole 3-acetic acid from L-tryptophan and their growth rate were studied. Differences in the levels of IAA synthesis and biomass production among the 8 mycorrhizal fungi were observed. A positive correlation was recorded between IAA level and mycelial growth. The synthesis of IAA and mycelial biomass were maximum on 30th day after incubation. Pisolithus tinctorius and Laccaria laccata exhibited higher amounts of IAA production than other fungi, whereas Amanita muscaria and Rhizopogon luteolus showed least quantity of IAA.