Species differences in the susceptibility to autotoxicity among leaf vegetables grown in hydroponics

Species differences to susceptibility to autotoxicity among leaf vegetables grown in hydroponics were studied. Shoot fresh weights of parsley, celery, mitsuba, curled lettuce, head lettuce, edible burdock, garland chrysanthem um, pak-choi and kale cultured in recycled (non-renewed) nutrient solution with and without the addition of activated charcoal to the nutrient solutio n was compared. Among the species, parsley suffered the most severe growth inhibition in the absence of charcoal, whereas komatsuna, chinese cabbage, radish, takana, welsh onion, perilla and spinach were unaffected. Thus, all species in Umbellifeae, Compositae and some species of Brassicaceae showed autotoxicity.