EFFECTS OF SOME CHEMICALLY INERT DUSTS UPON THE TRANSPIRATION RATE OF YELLOW COLEUS PLANTS

Abstract

Statistical analysis of data secured by morning and evening weighings of 90 potted yellow coleus plants [Coleus blumei], before and after dusting with chemically inert Bancroft clay, fine and coarse talc, and silica, showed that usually the night water loss only is increased, and then only when dusts with particles as small or smaller than the stomatal openings are applied to the stomata-bearing surface of the leaves. The increased water loss caused by dusting results from a change in stomatal, not cuticular, transpiration.