RELATION BETWEEN CHLOROPHYLL CONTENT AND PALENESS OF GIBBERELLIC ACID-TREATED LEAVES

The rate of chlorophyll synthesis as a function of lime was examined in plants of Hordeum vitlgare L. cultivated in Knop solution containing 1 mg/1 GA3. The action of concentration on the relations of chlorophyll components was investigated in GA3 solutions of five different concentrations. The relations of total chlorophyll contents, including those of the a and b components, were determined from ethanol and aqueous acetone extract at various periods of treatment, at the same moment but with different concentrations of GA3. A significant difference is noted between the chlorophyll contents of the GA3 treated plants and those of the control. The chlorophyll contents of treated plants are decreasing. The difference increases with raising GA3 concentration. The components were separated on thin layer with the partition method, and the spots were eluted. The density was measured with a spectrophotometer. Among the yellow components in the treated plants, the carotenes (α and β carotenes) increase as compared with the control plants. The total quantity of xanthophylls (lutein, zeaxanthine, lutein‐5, 6‐epoxide, violaxanthine and neoxanthine) almost equals the xanthophyll amount in the control plants; there is no significant difference. The paleness of leaves treated with GA3 is provoked by the quantitative change of pigment components; the chlorophylls o and b decrease, the xanthophylls remain unchanged and the carotenes increase. Copyright © 1969, Wiley Blackwell. All rights reserved