Abstract
The relative susceptibility of 30 cultivars of lettuce to inhibition by aflatoxin was studied. Seed germination was not inhibited by concentrations as high as 1,000 mug/ml in cultivar Imperial 44 or by 100 mug/ml in the remaining cultivars. Hypocotyl elongation was inhibited by 46 to 68% at a concentration of 100 mug of aflatoxin per ml. Seedlings exposed to aflatoxin did not become chlorotic. The similarity between the morphological reaction of plants to coumarin and aflatoxin suggests a common mode of action, but further studies of the physiological basis for the inhibitory reactions induced by these compounds will be necessary before such conclusions will be valid.