Effect of soil fungistasis on spore germination and germ-tube growth in Penicillium species

Abstract

A comparison has been made of the effect of soil fungistasis on the speed of germination, the final percentage germination, and the growth rate of germ-tubes for the spores of 11 species of Penicillium. Soil fungistasis was capable of depressing all three parameters of germination with severe reduction in percentage performance in some instances. For any single species soil fungistasis did not depress all three parameters of germination equally but there was, however, among the different species, no consistent tendency for any one parameter to be more affected than another. The effect of soil fungistasis on the speed of germination and its effect on the final percentage germination were positively correlated in the same species, but the effect of soil fungistasis on the growth rate of germ-tubes was not positively correlated within the same species either with the effect on the speed of germination or on the final percentage germination. A statistically significant negative correlation existed, however, between the results obtained for the growth rate of germ-tubes and the final percentage germination so that a severe reduction in performance in one tended to be accompanied by a slight reduction in performance in the other and vice versa. It is suggested that the effect of soil fungistasis on the growth rate of germ-tubes may, under some circumstances, be the most significant ecologically, but a complete assessment of the ecological effects of soil fungistasis on a fungus species can only be based on measurements of the effect on all three parameters of germination.