EFFECT OF TEMPERATURE ON GERMINATION AND GERM-TUBE DEVELOPMENT OF PUCCINIA-RECONDITA AND P-GRAMINIS UREDINIOSPORES

Germination of Puccinia recondita and P. graminis urediniospores reached at least 95 % within 2 h at temperatures of 6-28-degrees-C. Germination measured in both species was inhibited for at least 4 h at 2-degrees, greatly reduced at 31-degrees and completely inhibited at 35-degrees. Maximum development of P. recondita germ-tubes was recorded at 10, 14 and 220 within 17 h. In contrast, germ-tubes of P. graminis urediniospores developed to maximum lengths at 22 and 25-degrees within 17 h. Lysing of germ-tubes was evident (approximately 2 %) within 4 h at all temperatures of 6-31-degrees, but was considerably higher at 31-degrees. Branching and coiling of germ-tubes became more pronounced in both species with increase in temperature after 4 h incubation.