THE EFFECT OF TEMPERATURE ON THE GERMINATION OF TELIOSPORES OF PUCCINIA-PUNCTIFORMIS

Germination of teliospores was analyzed as a time-dependent process. Nonlinear regression was used to fit germination progress curves for 5, 10, 15, and 20 C. Germination was characterized by the maximum fraction of teliospores germinated, the mid germination time (one-half of the maximum germinated), and the rate of germination at the mid germination time. Temperature had a major effect on the mid germination time and, to a smaller extent, on the rate of germination. The mid germination time was shortest at 15 C, longer at 10 and 20 C, and longest at 5 C. The rate of germination was highest at 10 and 15 C and lower at 5 and 20 C. No effect of temperature was detected on the maximum fraction of teliospores germinated. The consequences of the germination dynamics for infection of Cirsium arvense root buds by Puccinia punctiformis are discussed.