VIEW ARTICLE

Techniques

A Semi-Micro Method for the Quantitation of Sesquiterpenoid Stress Metabolites in Potato Tuber Tissue. J. W. D. M. Henfling, Graduate student, University of Kentucky, Department of Plant Pathology, Lexington, KY 40546; J. Ku?, professor, University of Kentucky, Department of Plant Pathology, Lexington, KY 40546. Phytopathology 69:609-612. Accepted for publication 21 December 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-609.

A semi-micro method for quantitation of sesquiterpenoid stress metabolites in potato tuber tissue is described. The upper surfaces of two or three tuber slices, 3 cm in diameter and 5 mm thick, were inoculated with zoospores of an incompatible race of Phytophthora infestans. After incubation, the upper 1 mm of the slices was removed and two or three random samples from this tissue were extracted with methanol without homogenization. The residue remaining after evaporation of the methanol was partitioned in a test tube between water and ethyl acetate, and the organic layer was dried. The residue was dissolved in methanol and terpenoids were determined by gas liquid chromatography. The method is applicable to samples as small as 0.1 g; yields recoveries of 85–95% of added standards of phytuberol, phytuberin, rishitin, and lubimin; and permits the testing of several treatments on tissue from a single tuber.