Fine Structure of Spore Germination in Botrytis cinerea

SUMMARY The ultrastructure of germinating Botrytis cinerea conidia was studied using three different fixatives. Good fixation and embedment of dormant spores was achieved. The wall of the dormant spore was composed of two layers. During germination three new wall layers were formed between the original wall and the cytoplasm; the inner two layers were continuous around the spore cytoplasm whilst the third was formed only near the point of germ-tube emergence and was continuous with the germ-tube wall. The conidial wall increased in thickness from 263 to 339 nm. during germination. It was calculated that, as a result of spore swelling alone, the dormant spore wall would decrease in thickness from 263 to 178 nm. An apical corpuscle was observed in the germ-tube wall during germination.