Changes in biochemical components during the germination of spores of Penicillium roqueforti

Germination of spores of Penicillium roqueforti consisted of three stages, i.e. swelling, germ‐tube emergence and hyphal elongation which occurred at 4, 12 and 16 h respectively after initiation of incubation of resting spores in the germination medium. The swelling phase represents the period during which the germinating spore assembled required synthetic enzymes though there was only a small increase in dry weight (2 mg h−1 per 109 spores). Nuclear division occurred since DNA multiplied rapidly during spore swelling. The percentages of RNA and proteins reached their maxima at the end of this period. The unsaturated fatty acids, e.g. linoleic and linolenic acids, were synthesised. Germ‐tube emergence represented a transition phase during which growth was moderate (at a rate of 9 mg h−1 per 109 spores) as compared to hyphal elongation phase (34 mg h−1 per 109 spores). The percentage of RNA, proteins and carbohydrates decreased. The percentage of unsaturated fatty acids was highest at the middle of this period and then declined. The hyphal elongation phase represented a period of rapid growth. The relative contents of proteins and DNA remained constant while the percentage of carbohydrates and saturated fatty acids increased, reflecting the proliferation of cellular and membrane materials.