EFFECT OF EXTRACTS OF PYRENOPEZIZA-BRASSICAE ON THE REPRODUCTIVE DEVELOPMENT OF OTHER SPECIES OF FUNGI

Studies on the effect of culture extracts were found to throw a new li ght on the reproductive strategies of fungi. It was confirmed that ext racts of mated cultures of Pyrenopeziza brassicae stimulated the devel opment of ascocarp-like structures and suppressed asexual sporulation in unmated cultures of the same species. In contrast, all culture extr acts of P. brassicae, whether from mated or unmated cultures, affected the reproductive development of about 30 other species of fungi. In t hose species which are not known to reproduce sexually, the extracts s timulated asexual sporulation. In those species which are known only t o reproduce sexually the effect of the extracts was to stimulate sexua l reproduction, whereas in those species which are known to sporulate both sexually and asexually in culture, the effect of the extracts was to alter the balance in favor of sexual reproduction. In species whic h are known only to sporulate asexually, extract of uninoculated cultu re medium was as effective as the culture extracts in stimulating asex ual sporulation, presumably by supplying or replenishing spent nutrien ts. The effect of medium extract on sexual reproduction was slight but not statistically significant, suggesting that other substances, such as morphogens, initiate and sustain the process.