Abstract
The effect of dry wilting of petals and leaves on the sporulation ofBotrytis cinerea, the pathogen of gray mold disease, was examined using cucumber, eggplant and strawberry.
Sporulation on petals and leaves was accelerated by lyophilization or air-drying, but it was reduced on those dried at moist chamber and room temperature for 3 days. The increase in the numbers of conidia formed in response to drying was smaller on the petals than on the leaves.
Analysis of the free sugars and amino acids in eggplant petals and leaves revealed no difference between air-dried and non-dried plants, but showed a decrease in the sugar content and qualitative and quantitative changes in the amino acid composition after drying at room temperature for 3 days. The amino acids which decreased during 3 days drying promoted sporulation more than those not decreased by the drying, in the medium containing both amino acids and glucose. Sporulation was promoted at 0.5% more than 0.1% alanine, proline, glutamate, aspartate or methionine.
Judging from these results, the decrease in water content accompanying with the drying of petals and leaves is presumed to enhance sporulation by increasing the concentration of amino acids in the plant cells. After drying for 3 days, the amino acids which promote sporulation decreased metabolically, and then this fact might result in lower sporulation.
