ADHESION AND PRE-INVASION BEHAVIOR OF UREDINIOSPORES OF UROMYCES VICIAE-FABAE DURING GERMINATION ON HOST AND SYNTHETIC SURFACES

Dry urediniospores of Uromyces viciae-fabae will not germinate but will adhere to substrata. High humidity or free water initiate germination. Spores imbibe free water, swell and germ pores are lysed. Extracellular matrix is produced and possibly released through the germ pore. Emerging germ tubes are enclosed in a sheath of matrix and adhere tightly to the substratum. This is a non- specific response. Several factors, either singly or in combination, may induce the formation of appressorium-like structures. These are discussed in relation to the availability of water and the topography of the substratum surface. © 1990, British Mycological Society. All rights reserved.