The effects of antitranspirants on stomatal opening, and the proline and relative water contents in the tomato

Abstract

SummaryThe effects were examined of three antitranspirants, phenyl mercuric acetate (PMA), 8-hydroxyquinoline sulphate (8-HQ) and kaolinite on stomatal opening, proline content and the relative water content (RWC) in four tomato cultivars. Some 20–33% of stomata were closed in the different cultivars. There were significant differences in cultivar response, the reduction in stomatal aperture varying from 32% to 37% in the different cultivars. PMA was the most effective in reducing the stomatal aperture. Significant differences were observed between the cultivars both for proline content and RWC as affected by antitranspirants. Cv Arka Vikas had significantly higher proline content and RWC. PMA increased both proline and RWC. In tomato cultivars treated with antitranspirants there appeared to be a better maintenance of high values of RWC with a higher degree of stomatal control.