Published online by Cambridge University Press: 12 June 2017
Nitrofen (2,4-dichlorophenyl p-nitrophenyl ether) injured meristematic tissues and reduced germination and growth of cabbage (Brassica oleracea var. capitata L.) in the dark. Cabbage was more susceptible to nitrofen when the plants were grown under a low water potential or when they were maintained in the dark after spraying. This toxicity was overcome by exogenous sucrose and light was not required for nitrofen activity. Nitrofen promoted membrane permeability of red beet (Beta vulgaris L.) root sections and this was enhanced by dimethylsulfoxide (DMSO). Sucrose or Carbowax 1500 prevented this increase in permeability. Nitrofen inhibited non-cyclic photophosphorylation and electron transport in isolated spinach (Spinacia oleracea L.) chloroplasts and increased oxygen uptake of cabbage leaf sections. These effects appeared dependent upon permeability. Nitrofen induced stomatal closure, decreased transpiration, and increased leaf temperature. The leaf sustains thermal injury under high temperatures or high light intensities.