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Hormonal changes in relation to biomass partitioning and shoot growth impairment in salinised tomato (Solanum lycopersicum L.) plants.

Albacete, Alfonso and Ghanem, Michel Edmond and Martínez-Andújar, Cristina and Acosta, Manuel and Sanchez-Bravo, Jose and Martinez, Vicente and Lutts, Stanley and Dodd, Ian C. and Pérez-Alfocea, Francisco (2008) Hormonal changes in relation to biomass partitioning and shoot growth impairment in salinised tomato (Solanum lycopersicum L.) plants. Journal of Experimental Botany, 59 (15). pp. 4119-4131. ISSN 1460-2431

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    Abstract

    Following exposure to salinity, the root/shoot ratio is increased (an important adaptive response) due to the rapid inhibition of shoot growth (which limits plant productivity) while root growth is maintained. Both processes may be regulated by changes in plant hormone concentrations. Tomato plants (Solanum lycopersicum L. cv Moneymaker) were cultivated hydroponically for 3 weeks under high salinity (100 mM NaCl) and five major plant hormones (abscisic acid, ABA; the cytokinins zeatin, Z, and zeatin-riboside, ZR; the auxin indole-3-acetic acid, IAA; and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid, ACC) were determined weekly in roots, xylem sap, and leaves. Salinity reduced shoot biomass by 50–60% and photosynthetic area by 20–25% both by decreasing leaf expansion and delaying leaf appearance, while root growth was less affected, thus increasing the root/shoot ratio. ABA and ACC concentrations strongly increased in roots, xylem sap, and leaves after 1 d (ABA) and 15 d (ACC) of salinization. By contrast, cytokinins and IAA were differentially affected in roots and shoots. Salinity dramatically decreased the Z+ZR content of the plant, and induced the conversion of ZR into Z, especially in the roots, which accounted for the relative increase of cytokinins in the roots compared to the leaf. IAA concentration was also strongly decreased in the leaves while it accumulated in the roots. Decreased cytokinin content and its transport from the root to the shoot were probably induced by the basipetal transport of auxin from the shoot to the root. The auxin/cytokinin ratio in the leaves and roots may explain both the salinity-induced decrease in shoot vigour (leaf growth and leaf number) and the shift in biomass allocation to the roots, in agreement with changes in the activity of the sink-related enzyme cell wall invertase.

    Item Type: Article
    Journal or Publication Title: Journal of Experimental Botany
    Additional Information: This is an electronic version of an article published in Journal of Experimental Botany, 59 (15), 2008, p. 4119-4131.
    Uncontrolled Keywords: Abscisic acid ; 1-aminocyclopropane-1-carboxylic acid ; indole-3-acetic acid ; plant hormones ; salt stress ; sodium chloride ; tomato (Solanum lycopersicum L.) ; zeatin ; zeatin-riboside
    Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
    Departments: Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 30903
    Deposited By: Mr Richard Ingham
    Deposited On: 10 Dec 2009 14:01
    Refereed?: Yes
    Published?: Published
    Last Modified: 06 Sep 2013 19:45
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/30903

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