The effect of heat shock on differentiation of germinating conidia of Trichoderma viride

Studies on the germination of Trichoderma viride spores indicate that they lose their resistance to heat at an early stage of germination. Whereas dormant conidia were resistant to 46 °C, the same treatment given 4 h after the onset of germination was lethal to the germinating spores. A milder thermal treatment (45 °C for 10 min) given during the first 2 h of incubation caused a delay both of swelling of conidia and appearance of germ tubes.Sensitivity of spores to heat was dependent on the temperature, duration of treatment, and incubation in a nutrient medium before application of the thermal treatment.Increase in oxygen uptake, rate of protein synthesis, and RNA synthesis were observed 2–3 h after the onset of germination. Ultrastructural changes were first observed after 4 h of germination. Application of the mild thermal treatment during the first 2 h of germination resulted in a delay in the observed increase in oxygen uptake, protein synthesis, swelling, and ultrastructural development, as well as ...