Einfluβ von Zeatin auf den Kohlenhydrat- und Stickstoffhaushalt vegetativer Pflanzenteile

Abstract

The naturally occurring cytokinin zeatin was administered to intact plants of Coleus blumei and Impatiens sultani four times at weekly intervals. When treating only the young leaves near the apex in Coleus in September/October we find a decrease of the content of sugars and an increase of starch in the leaves. In Februar/March the reverse is true. In Impatiens in Feb/March the content of starch and sugars increases. The different effects in autumn and late winter perhaps result from the different quantity of light or from the different photoperiod at the time of application. The influence of zeatin on the storage of carbohydrates may be interpreted as a general enhancement of anabolic processes without a fundamental alteration of the metabolic situation. In leaves of Coleus in Oct. zeatin causes an increase of total nitrogen, especially due to a strong rise of the soluble nitrogen. When zeatin (10 ppm) was administered by pencil to all green leaves of the plants the protein-N decreases, probably as a consequence of a high hormone supply. The amino acid composition of the TCA-precipitable proteins of the leaves is changed by zeatin. The effects of zeatin are very similar to those of kinetin. The experiments described here, and some other investigations concerned with the influence of zeatin on the composition of lipid fatty acids and on the respiration of leaves, show that too high concentrations of the hormone have a negative influence on metabolism. These disturbances are naturally more obvious regarding N-compounds than in respect to the storage of carbohydrates.