Cytokinin activities in cells of wheat inflorescence in depependence of its developmental stage.

We demonstrate that differences in the endogenous biologically active levels and patterns of cytokinins depend on the organ differentiation, i. e. immature inflorescence before meiosis and immature embryo 14 days after anthesis, respectively, in winter wheat of two genotypes: Grana and Almari. Two cell lines were subjected to analysis of cytokinin contents. Higher levels of endogenous cytokinin were found in cells derived from immature embryo (E) in comparison to cells obtained from immature inflorescence (I). The levels of zeatin ryboside ([9R]Z) and benzyladenosine ([9R]BAP) were predominant and isopentenyladenine (iP) was very low for the cells E of both genotypes. The cytokinin amounts in cells E and I of the zeatin group were smaller than those of other groups. We suggest that the concentration of cytokinins in tissue capable of generative development in winter wheat should be on a level that occurred in inflorescence cell lines, in comparison to immature embryo cell lines. These results indicate that the effect of the developmental stage of ears of wheat on the capability to flower in winter wheat plants regenerated in in vitro culture may be induced by the hormone level.

Effect of high temperature treatment of Vicia faba roots on the oxidative stress enzymes in leaves.

The following types of superoxide dismutase (SOD) have been found in the leaves of Vicia faba: one isoenzyme of Mn-SOD and four isoenzymes of Cu/Zn-SOD. The treatments of roots with boiling water caused an increase of SOD activity in the leaves. The highest increase was measured after 5 s of the treatment. It was accompanied by a significant increase in catalase activity. Analysis of cell fractions' revealed an increase of SOD activity in the plastids and mitochondria isolated from the leaves of those plants whose roots were heat-treated. However, there was no distinct change of SOD activity in the cytosolic fraction. The possibility of an electric wave intervention inducing oxidative stress in the leaves is discussed.