The impact of water deficit progression on cytokinin (CK), auxin and abscisic acid (ABA) levels was followed in upper, middle and lower leaves and roots of Nicotiana tabacum L. cv. Wisconsin 38 plants [wild type (WT)]. ABA content was strongly increased during drought stress, especially in upper leaves. In plants with a uniformly elevated total CK content, expressing constitutively the trans-zeatin O-glucosyltransferase gene (35S::ZOG1), a delay in the increase of ABA was observed; later on, ABA levels were comparable with those of WT. As drought progressed, the bioactive CK content in leaves gradually decreased, being maintained longer in the upper leaves of all tested genotypes. Under severe stress (11 d dehydration), a large stimulation of cytokinin oxidase/dehydrogenase (CKX) activity was monitored in lower leaves, which correlated well with the decrease in bioactive CK levels. This suggests that a gradient of bioactive CKs in favour of upper leaves is established during drought stress, which might be beneficial for the preferential protection of these leaves. During drought, significant accumulation of CKs occurred in roots, partially because of decreased CKX activity. Simultaneously, auxin increased in roots and lower leaves. This indicates that both CKs and auxin play a role in root response to severe drought, which involves the stimulation of primary root growth and branching inhibition.

Institute of Experimental Botany AS CR Rozvojova 263 165 02 Prague 6 Czech Republic

References provided by Crossref.org

Epigenetics and plant hormone dynamics: a functional and methodological perspective

IPT9, a cis-zeatin cytokinin biosynthesis gene, promotes root growth

A Glyphosate-Based Herbicide in Soil Differentially Affects Hormonal Homeostasis and Performance of Non-target Crop Plants

Response of cytokinins and nitrogen metabolism in the fronds of Pteris sp. under arsenic stress

Heat Acclimation and Inhibition of Cytokinin Degradation Positively Affect Heat Stress Tolerance of Arabidopsis

Light Regulates the Cytokinin-Dependent Cold Stress Responses in Arabidopsis

Correlations between Phytohormones and Drought Tolerance in Selected Brassica Crops: Chinese Cabbage, White Cabbage and Kale

Isoprenoid-derived plant signaling molecules: biosynthesis and biological importance

Evaluation of reference genes for reverse transcription quantitative real-time PCR (RT-qPCR) studies in Silene vulgaris considering the method of cDNA preparation

Depletion of carbohydrate reserves limits nitrate uptake during early regrowth in Lolium perenne L

Studying Secondary Growth and Bast Fiber Development: The Hemp Hypocotyl Peeks behind the Wall

Cytokinin-Specific Glycosyltransferases Possess Different Roles in Cytokinin Homeostasis Maintenance

The role of cis-zeatin-type cytokinins in plant growth regulation and mediating responses to environmental interactions

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants

Plastidic phosphoglucose isomerase is an important determinant of starch accumulation in mesophyll cells, growth, photosynthetic capacity, and biosynthesis of plastidic cytokinins in Arabidopsis

Quo vadis plant hormone analysis?

Enhanced drought and heat stress tolerance of tobacco plants with ectopically enhanced cytokinin oxidase/dehydrogenase gene expression

Recovery from drought stress in tobacco: an active process associated with the reversal of senescence in some plant parts and the sacrifice of others

Transferases and transporters mediate the detoxification and capacity to tolerate trinitrotoluene in Arabidopsis

Characterization of new maize genes putatively involved in cytokinin metabolism and their expression during osmotic stress in relation to cytokinin levels