[Gibberellic acid and chlorophyll content of leaves of phaseolus vulgaris L].

Chlorophyll contents of slightly chlorotic Phaseolus vulgaris L. leaves which had developed in the presence of various GA3 concentrations (0.01, 1, 10 and 100 ppm.) were determined and compared with those of the leaves of control plants. The test plants were raised in Knop's solution, under controlled conditions in a climate chamber; the chlorophyll was extracted on the 6th and 10th day after GA3 treatment had been started. After having been separated into their components on thin layer chromatograms, the pigment spots were eluted and their concentration was determined by means of a spectrophotometer. The quantity of total chlorophyll and of the components is expressed in μg/g fresh weight and represented on diagrams.Our findings can be summed up as follows: (1) As a result of GA3 treatment, the total chlorophyll content per surface unit of the leaf decreases, the decrease being proportional to the increase in concentration of GA3. (2) Particularly in the case of higher GA3 concentrations, the decrease in the contents of chlorophyll-a is larger than that of chlorophyll-b. (3) The quantity of carotenes is almost doubled in the presence of 100 ppm. GA3. (4) An approximative decrease of 10% is to be noted in the quantity of xanthophylls (lutein+violaxanthine+neoxanthine). (5) Since these quantitative changes agree in many respects with those observed in the case of Hordeum (SZALAR, 1968), it may be assumed with utmost probability that GA3 treatment results in a significant decrease of chlorophyll contents, probably not only in the case of the plants involved in the present work.