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Hormonal changes during salinity-induced leaf senescence in tomato (Solanum lycopersicum L.)

Ghanem, Michel Edmond and Albacete, Alfonso and Martínez-Andújar, Cristina and Acosta, Manuel and Romero-Aranda, M. Remedios and Dodd, Ian C. and Lutts, Stanley and Pérez-Alfocea, Francisco (2008) Hormonal changes during salinity-induced leaf senescence in tomato (Solanum lycopersicum L.). Journal of Experimental Botany, 59 (11). pp. 3039-3050. ISSN 1460-2431

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    Abstract

    Leaf senescence is one of the most limiting factors to plant productivity under salinity. Both the accumulation of specific toxic ions (e.g. Na+) and changes in leaf hormone relations are involved in the regulation of this process. Tomato plants (Solanum lycopersicum L. cv Moneymaker) were cultivated for 3 weeks under high salinity (100 mM NaCl) and leaf senescence-related parameters were studied during leaf development in relation to Na+ and K+ contents and changes in abscisic acid (ABA), cytokinins, the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and the auxin indole-3-acetic acid (IAA). Na+ accumulated to a similar extent in both leaves 4 and 5 (numbering from the base of the plant) and more quickly during the third week, while concurrently K+ contents sharply decreased. However, photosystem II efficiency, measured as the Fv/Fm ratio, decreased from the second week of salinization in leaf 4 but only at the end of the third week in the younger leaf 5. In the prematurely senescent leaf 4, ABA content increased linearly while IAA strongly decreased with salinization time. Although zeatin (Z) levels were scarcely affected by salinity, zeatin-riboside (ZR) and the total cytokinin content (Z+ZR) progressively decreased by 50% from the imposition of the stress. ACC was the only hormonal compound that increased in leaf tissue coincident with the onset of oxidative damage and the decline in chlorophyll fluorescence, and prior to massive Na+ accumulation. Indeed, (Z+ZR) and ACC contents and their ratio (Z+ZR/ACC) were the hormonal parameters best correlated with the onset and progression of leaf senescence. The influence of different hormonal changes on salt-induced leaf senescence is discussed.

    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 (11), 2008, p. 3039-3050.
    Uncontrolled Keywords: Abscisic acid ; 1-aminocyclopropane-1-carboxylic acid ; indole-3-acetic acid ; plant hormones ; salt stress ; senescence ; 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: 30905
    Deposited By: Mr Richard Ingham
    Deposited On: 10 Dec 2009 14:38
    Refereed?: Yes
    Published?: Published
    Last Modified: 06 Sep 2013 19:45
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/30905

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