Phytohormones and the Culture of Agaricus bisporus (Lange) Pilat

Abstract

Addition of synthetic phytohormones (auxin, gibberellin and cytokinin) to Agaricus bisporus culture matte promoted mycelial growth significantly at concentrations of 16° - 107 M. Most of the tested phytohormones were more effective in growth promotion in liquid culture rather than on semi-solid agar . Phytohormones stimulated hyphal cell division and cell elongation . Increased yield was obtained by watering compost and casing soil with solutions of gibberellic acid ,α-naphthalene acetic acid and 2,4-dichlorophenoxy acetic acid ,while indole-3-acetic acid and kinetin were without marked effects .The average weight of fruit body was increased by addition of most of the tested phytohormones ,but it was at the expense of the number of sporophores . In general, synthetic phytohormones did not effect the shape of the sporophore, but stipe length and pileus diameter were increased by some phytohormones . Malt extract was shown to have auxin, gibberellin and cytokinin activity which may explain its superiority in formation of primordia over other media . Addition of synthetic phytohormones to malt extract agar accelerated primordium initiation and significantly increased number over the control . Compost and casing soil contained appreciable amounts of the three groups of phytohormones (auxins, gibberellins and cytokinins). The fluctuation in levels of phytohormones in compost and casing soil were related to fluctuations in the population of bacteria and fungi. Phytohormones play a role in regulating the interaction between A. bisporus and other micro-organisms in artificial culture . The mycelium of A. bisporus and selected isolates of bacteria and fungi synthesise and utilize auxin, gibberellin and cytokinin . High concentrations of phytohormones in the primordium stage compared to those in mycelium and fruit body stages,and the inverse correlation between phytohormone content and the age of developing fruit bodies, suggest that phytohormones function in the development of fruit bodies. In general, phytohormones influence vegetative growth , transition from vegetative to reproductive growth and the development of fruit bodies of Agaricus bisporus.