FOLIAR REFLECTANCE, GROWTH AND PHYSIOLOGICAL RESPONSES OF MAIZE AND TOMATO TO AN OPTICAL BRIGHTENER

Abstract

The effects of the optical brightener Tinopal® C1101 (an ethenediyl benzenesulfonic derivative) at 1 and 3 % (w/v) on the reflectance, growth, photosynthesis and stomatal conductance of two crops, maize (Zea mays L.) and tomato (Solanum lycopersicum L.), were evaluated. Application of the optical brightener increased reflectance on maize and tomato leaf surfaces ranging from 1.5 to 2.5 and 1.6 to 1.9 fold, respectively, in the wavelength regions corresponding to the absorption spectra of chlorophylls a and b. Continuous application of Tinopal® C1101 1 and 3 % on maize plants under greenhouse conditions, affected plant height, leaf area and dry weight (P ≤ 0.05). In contrast, such treatments did not affect growth of tomato plants. The application of this brightener did not affect the photosynthetic rate nor stomatal conductance of maize and tomato. These results showed that the effects of this optical brightener on plant growth could be related with structural or physiological differences among plant species.