ROLE OF TRACE ELEMENTS IN THE GROWTH AND MORPHOLOGY OF FIVE ASCOSPORIC ASPERGILLUS SPECIES

Abstract

The effect of copper, iron, molybdenum, boron, manganese, and zinc on the growth, morphology, and fruiting of five species of Aspergillus nidulans group was examined under controlled conditions. The fungi were A. nidulans (Eidam) Wint., A. rugulosus Thom and Raper, A. violaceus Fennell and Raper, A. varie-color (Berk. & Br.) Thom and Raper, and A. quadrilineatus Thom and Raper. Significantly less growth was noticed in all the fungi when all six trace elements were omitted from the culture medium. Also, marked morphological changes occurred in the mycelia and conidiophores of these fungi. The essentiality of manganese, iron, and zinc for growth and fruiting was established for all five fungi. In manganese-deficient cultures the mats were heavily wrinkled and several interesting changes and abnormalities were observed in the conidiophores. The reduction in growth in cultures deficient in copper, boron, and molybdenum varied with the species and their deficiency did not seem to reduce sporulation of these molds. Copper deficiency affected the pigmentation of these aspergilli.