1THE EFFECT OF GALACTOSE ON THE GROWTH OF LEMNA

Solutions of 0·1% galactose were toxic to Lemna gibba in axenic culture. The toxicity was counteracted by glucose and exacerbated by ethanol. Plants showing toxicity accumulated large amounts of starch and showed a mineral analysis typical of ageing fronds. Radioactively labelled galactose was readily transformed to glucose by plants in toxic conditions. The distribution of activity suggests only a slight impairment of cellulose synthesis. Although hormonal disturbances are probably involved, the fact that galactose is toxic to both plants and animals suggests that a more fundamental aspect of metabolism is involved.