Developmental changes in the Ca-45(2+) uptake by Trichoderma viride mycelium

The rate of the Ca-45(2+) uptake by the submerged Trichoderma viride mycelium increased with the age of the culture from 6 h until a maximum which was reached at about 30 h, and then decreased until the uptake was virtually zero. The decrease in the rate of the Ca-45(2+) uptake was accompanied by an increase of mycelial mass. The uptake rate could not be reactivated upon substituting the medium for a fresh one, without or with dilution of the mycelium. The results suggest that the rate of Ca-45(2+) uptake reflects the biological age of the submerged culture. The surface-cultivated mycelium took up Ca-45(2+) proportionally with time. The autoradiography of colonies showed that Ca-45(2+) was distributed homogeneously throughout the mycelium during vegetative growth while conidiation was accompanied by a massive accumulation of Ca-45(2+) in conidia.