Chlorogenic acid and other o-dihydricphenols were found to accumulate rapidly in the area adjacent to the cut surface of potato tuber slices held at room temperature in a moist chamber.
The rate of accumulation was found to be decreased by: (1) holding the slices at lower temperature; (2) dipping the slices in resorcinol solution; (3) dipping slices in sodium bisulfite-sodium chloride solution; (4) immersion of whole tubers in water (room temperature) for 24 hours prior to slicing.
The same phenolic substances which accumulated in tuber slices were found to accumulate in necrotic areas of tubers infected with aster yellows.
Ascorbic acid was found to accumulate in tuber slices but rapidly decreased after the second day of holding at room temperature.
Several ways in which phenolic substances can function in the mechanism of disease resistance are discussed.
The possibility that the accumulation of oxidized products of ascorbic acid adjacent to infected tissue may play a role in disease resistance is also discussed.