Movement of nutrients in fungi. II. The effect of reproductive structures

Abstract

Movement of labelled nutrients was investigated in a number of fungi which were producing reproductive structures (perithecia, basidiocarps, conidia, sclerotia). In every case markedly greater quantities of labelled nutrients were present in the reproductive structures than in the growing vegetative hyphae. In Phycomyces blakesleeanus, a species in which cytoplasmic streaming may be initiated by evaporation from sporangiophores, transport of label was found to occur at both low and high humidity, but there was faster movement at low humidity.

It is concluded that transport of nutrients in the fungi may occur without the intervention of cytoplasmic streaming. The mechanism is unknown but it is apparently associated with a concentration gradient between sites of absorption from the substrate and sites of active metabolic removal at the growing apices or developing reproductive structures.

Competition for nutrients between reproductive structures and vegetative hyphae may severely limit the ability of the mycelium to colonize non-nutrient substrates.