Studies with antitranspirants on coffee (Coffea arabica L.)

Abstract

Young coffee plants were sprayed during a period of stress with phenyl-mercuric acetate (PMA) at rates between 10-4 and 10-2M or maleic hydrazide (MH) at 10-4 to 10-1M, or with distilled water, the spray being directed to the abaxial side of the leaf bearing stomata. Data are presented on the effects on transpiration, leaf water potential and succulence (the ratio of the difference between the fresh weight and the dry weight of leaf discs to their fresh weight), assessed daily for 4 days. Leaf water potential and succulence were increased, and transpiration reduced, by both chemicals. The optimum concentration of MH was 10-1M. PMA was phytotoxic.