Chlamydospore germination in Phytophthora drechsleri

Abstract

Chlamydospores of Phytophthora drechsleri Tucker germinated readily on solute-amended agars with potentials as low as — 98·5 bar, whereas mycelium from mycelia inocula failed to grow at potentials lower than — 56 bar. Formation of cross walls within germ tubes was common but subsequent growth was not affected. During germination the spore wall often split and separated from the protoplast. No swelling prior to germination was evident. The ability of chlamydospores to germinate at low water potentials is discussed in relation to a field situation and the presence of root rot in samower crops growing in dry soils.