On Autotropism in Botrytis: Measurement Technique and Control by CO2

The mutual orientation of the germination of nearby pairs of Botrytis spores growing in a simple, dilute medium was studied. If the medium is equilibrated with room air, they show a very strong tendency to germinate both toward each other and in a cis arrangement, i.e., toward the same side of the line joining their centers. If the medium is equilibrated with air enriched with 0.3% or 3% CO(2), (i.e., 10 or 100 times the normal CO(2) concentration) then the cells show an equally strong tendency to germinate away from each other. The interaction shows little dependence upon pH.