Publications

Cytokinin is known to be involved in many processes related to plastid development and function but the exact role of cytokinin in photosynthesis remains elusive. To investigate more profoundly the effects of cytokinin in this process, the photosynthetic activity of transgenic Pssu-ipt and 35S:CKX1 tobacco (Nicotiana tabacum) plants with respectively elevated and reduced endogenous cytokinin content was evaluated. Pigment analysis indicated ...

The aim of the present report was to demonstrate how a novel approach for immunohistochemical localization of cytokinins in the leaf and particularly in the phloem may complement to the study of their long-distance transport. Different procedures of fixation were used to conjugate either cytokinin bases or their ribosides to proteins of cytoplasm to enable visualization and differential localization of these cytokinins in the leaf cells of wheat ...

Cytokinin flow from roots to shoots can serve as a long-distance signal important for root-to-shoot communication. In the past, changes in cytokinin flow from roots to shoots have been mainly attributed to changes in the rate of synthesis or breakdown in the roots. The present research tested the possibility that active uptake of cytokinin by root cells may also influence its export to shoots. To this end, we collapsed the proton gradient across ...

The choice of a cytokinin can make the difference between success and failure in the micropropagation system of a plant species. Cytokinins show stimulatory and inhibitory effects during all kinds of developmental processes such as root inhibition, shoot branching, shoot induction and senescence. Natural cytokinins are N6-substituted purine derivatives which can be classified by the configuration of their N6-side chain as isoprenoid or aromatic ...

The regulation of photosynthetic acclimation to canopy density was investigated in tobacco canopies and in tobacco and Arabidopsis plants with part of their foliage experimentally shaded. Both species acclimated to canopy light gradients and partial shading by allocating photosynthetic capacity to leaves in high light and adjusting chloroplast organization to the local light conditions. An investigation was carried out to determine whether ...

Rhodococcus fascians is a well-adapted soil bacterium that interacts with many plants species. Infection leads to the induction of multiple stunted shoots, resulting in the typical leafy galls. As its virulence is strictly dependent on its capacity to produce cytokinins, and the abundant shoot proliferation is a typical cytokinin effect, research on R. fascians has mainly focused on the role of these phytohormones (reviewed in Stes et al., ...

In the past 20 years, the effect of topolins, a new group of cytokinins has been studied in tissue cultures of several plant species. Quite a few research groups have shown that in many cases they are a better alternative of benzyladenine. Indeed, the choice of a cytokinin can make the difference between success or failure in the micropropagation system of a plant species. Own research results and that of colleagues will be discussed. The ...

In vitro cloning of Phalaenopsis hybrids is generally characterized by slow growth and low multiplication rates. Therefore, the impact of 6-(3-fluorobenzylamino)purine (FmT) and its 9-beta-D-riboside (FmTR) was evaluated. These halogenated compounds have been selected based on their very high cytokinin activity in previous bioassays. The Phalaenopsis plantlets formed significantly more, but smaller new shoots when treated with FmTR (25.3) ...

Decades ago, the importance of cytokinins (CKs) during Rhodococcus fascians pathology had been acknowledged, and an isopentenyltransferase gene had been characterized in the fas operon of the linear virulence plasmid, but hitherto, no specific CK(s) could be associated with virulence. We show that the CK receptors AHK3 and AHK4 of Arabidopsis thaliana are essential for symptom development, and that the CK perception machinery is induced upon ...