Biochemical changes in infection droplets containing spores of Botrytis spp. Incubated in the seed cavities of pods of bean (Vicia faba L.)

SUMMARY Infection droplets containing spores of Botrytis cinerea become inhibitory to the growth of germ tubes of the fungus within 18 hr. of their incubation in bean pods. The inhibition is caused by an ether‐soluble substance, which has been partially purified, and which counteracts the stimulatory effect of sucrose, glucose, fructose, galacturonic acid and several amino acids, which are also present in the infection droplets. Changes in concentration of these substances have been described in the first 24 hr. after placing infection droplets in pods. The only major difference between droplets containing B. fabae and B. cinerea concerns the nature of the ether‐soluble substances produced. Following B. fabae infection a biologically inactive u.v. absorbing substance appears in high yield in place of the antifungal substance formed following B. cinerea infections.