Growth of AM fungi on in vitro root organ culture of Sorghum vulgare and Saccharum officinarum.

Spores of Gl mosseae and Gig gigantea germinated on minimal medium produced extraradical mycelium. Gl. mosseae infected roots of S. officinarum in in vitro condition were inoculated in M medium with in vitro cultured roots of Sorghum vulgare (test roots). From the infected root of S. officinarum, the mycelium developed and it infected the test roots. The roots developed new mycelia and further the mycelia produced a few hyaline spores. In MS medium combined with soil extract, root exudate, thiamine HCl and inositol combination, spore germination and germ tube growth were higher when compared with other media.

Axenic germination of Scutellospora erythropa and Scutellospora nigra in in vitro conditions.

Spores of Scutellospora erythropa and Scu. nigra isolated from neem rhizosphere soils from coastal regions of Chennai were tested for axenic germination in in vitro conditions. They showed positive results in media of different composition using root exudates, soil extract, thiamine HCl and inositol. The combined medium increased the spore germination in Scu. erythropa and in Scu. nigra over water agar control. The germ tube often grew up to 3.8 cm on combined media but no vegetative spores and extramatrical auxillary cells were observed during the experiment. There was significant increase in hyphal growth when the roots were introduced into the medium, 3 days after spore germination.

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.