Xylem-borne cytokinins: still in search of a role?

• Published in: Journal of experimental botany Vol. 57; no. 1; pp. 1 - 4
• Main Authors: Dodd, Ian C, Beveridge, Christine A
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 2006; Oxford Publishing Limited (England)
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cytokinins; Cytokinins - physiology; Economic plant physiology; Fundamental and applied biological sciences. Psychology; leaf development; leaf growth; Leaves; literature reviews; long-distance signalling; Nitrates; Nitrogen; Nitrogen - physiology; nutrient deficiencies; Opinion Paper; Plant growth; Plant growth regulators; Plant Leaves - growth & development; plant nutrition; plant physiology; Plant roots; Plants; signal transduction; simulation models; Transgenic plants; Water relations, transpiration, stomata; Xylem; Cytokinins; Xylem; Growth; nitrogen; leaf growth; long-distance signalling; Plant leaf; Cytokinin
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erj021

Leaf expansion and xylem cytokinin concentration ([X-CK]) decrease in response to nitrogen (N) deprivation. Debate continues over cause, effect, and correlation. Supporting studies provide, at best, correlative evidence that [X-CK] controls leaf growth in response to N-deprivation, while dissenting studies indicate that leaf growth responses to N can be independent of changes in X-CK supply to leaves. A model is proposed to evaluate the physiological significance to leaf growth of changes in plant and environment N concentrations, and plant CK concentrations.