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Rootstock-mediated changes in xylem ionic and hormonal status are correlated with delayed leaf senescence and increased leaf area and crop productivity in salinised tomato.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Published
  • Alfonso Albacete
  • Cristina Martínez-Andújar
  • Michel Edmond Ghanem
  • Manuel Acosta
  • Jose Sanchez-Bravo
  • Maria J. Asins
  • Jesus Cuartero
  • Stanley Lutts
  • Ian C. Dodd
  • Francisco Pérez-Alfocea
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<mark>Journal publication date</mark>07/2009
<mark>Journal</mark>Plant, Cell and Environment
Issue number7
Volume32
Number of pages11
Pages (from-to)928-938
Publication StatusPublished
<mark>Original language</mark>English

Abstract

Tomato crop productivity under salinity can be improved by grafting cultivars onto salt-tolerant wild relatives, thus mediating the supply of root-derived ionic and hormonal factors that regulate leaf area and senescence. A tomato cultivar was grafted onto rootstocks from a population of recombinant inbred lines (RILs) derived from a Solanum lycopersicum × Solanum cheesmaniae cross and cultivated under moderate salinity (75 mm NaCl). Concentrations of Na+, K+ and several phytohormones [abscisic acid (ABA); the cytokinins (CKs) zeatin, Z; zeatin riboside, ZR; and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC)] were analysed in leaf xylem sap in graft combinations of contrasting vigour. Scion leaf area correlated with photosystem II (PSII) efficiency (Fv/Fm) and determined fruit productivity. Xylem K+ (but not Na+), K+/Na+, the active CK Z, the ratio with its storage form Z/ZR and especially the ratio between CKs and ACC (Z/ACC and Z + ZR/ACC) were positively loaded into the first principal component (PC) determining both leaf growth and PSII efficiency. In contrast, the ratio ACC/ABA was negatively correlated with leaf biomass. Although the underlying physiological mechanisms by which rootstocks mediate leaf area or chlorophyll fluorescence (and thus influence tomato salt tolerance) seem complex, a putative potassium–CK interaction involved in regulating both processes merits further attention.