ULTRASTRUCTURAL AND HISTOCHEMICAL-STUDIES ON MYCELIAL GERMINATION OF SCLEROTIA OF SCLEROTINIA MINOR

The morphological and histochemical changes that occur during mycelial germination of sclerotia of Sclerotinia minor are described and discu ssed. Germ hyphae, which are initiated in the outer regions of the scl erotium, pass through degenerating outer medullary and cortical hyphae to emerge individually through the rind and aggregate outside the scl erotium to form a mycelium. This type of mycelial germination is descr ibed as 'noneruptive'. Almost all intra- and extracellular sclerotial reserves are utilized in the production of germ hyphae. The breakdown of these reserves is compared with breakdown during other forms of scl erotial germination and the possibility of translocatory hyphae being involved is suggested.