Rhizobacteria Inoculation Effects on Phytohormone Status of Potato Microclones Cultivated In Vitro under Osmotic Stress.

Water deficits inhibit plant growth and decrease crop productivity. Remedies are needed to counter this increasingly urgent problem in practical farming. One possible approach is to utilize rhizobacteria known to increase plant resistance to abiotic and other stresses.

Study of cytokinin transport from shoots to roots of wheat plants is informed by a novel method of differential localization of free cytokinin bases or their ribosylated forms by means of their specific fixation.

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 plants. In parallel to immunolocalization of cytokinins in the leaf cells, we immunoassayed distribution of free bases of cytokinins, their nucleotides and ribosides between roots and shoots of wheat plants as well as their presence in phloem sap after incubation of leaves in a solution supplemented with either trans-zeatin or isopentenyladenine.

Cytokinin producing bacteria stimulate amino acid deposition by wheat roots.

Phytohormone production is one mechanism by which rhizobacteria can stimulate plant growth, but it is not clear whether the bacteria gain from this mechanism. The hypothesis that microbial-derived cytokinin phytohormones stimulate root exudation of amino acids was tested. The rhizosphere of wheat plants was drenched with the synthetic cytokinin trans-zeatin or inoculated with Bacillus subtilis IB-22 (which produces zeatin type cytokinins) or B.

Accumulation of cytokinins in roots and their export to the shoots of durum wheat plants treated with the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP).

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.

Effect of partial root excision on shoot water relations.

Removing 4 out of 5 serminal roots from 7-day-old wheat seedlings arrested leaf elongation for 1.5 h. This effect can be explained by an initial decrease in foliar water content resulting from the smaller root surface area available for water uptake.