title: Effect of cadmium and calcium treatments on phytochelatin and glutathione levels in citrus plants.
abstract: Industry residues, phosphate fertilisers and wastewater as a source of irrigation have considerably increased levels of heavy metals in the soil, mainly cadmium (Cd(2+)). To test the effects of a calcium (Ca(2+)) treatment on Cd(2+) accumulation and plant tolerance to this heavy metal, plants of two citrus genotypes, Cleopatra mandarin (CM) and Carrizo citrange (CC), were watered with increasing concentrations of Cd(2+), and phytochelatin (PC) and glutathione (GSH) content were measured. Both genotypes were able to synthesise PCs in response to heavy metal intoxication, although CM seems to be a better Cd(2+) excluder than CC. However, data indicate that CC plants had a higher capacity for regenerating GSH than CM plants. In this context, the effects of Ca(2+) treatment on Cd(2+) accumulation, plant survival and PC, GSH and oxidised glutathione (GSSG) content were assessed. Data indicate that treatment with Ca(2+) had two positive effects on citrus physiology: it reduced Cd(+2) uptake into roots and also increased GSH content (even in the absence of Cd(2+)). Overall, the data indicate that although Cd(2+) exclusion is a powerful mechanism to avoid heavy metal build-up into photosynthetic organs, the capacity to maintain optimum GSH levels to feed PC biosynthesis could also be an important factor in stress tolerance.
authors.affiliation: Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, Castelló, Spain.
authors.forename: M F
authors.initials: MF
authors.lastname: López-Climent
authors.affiliation: Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, Castelló, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Arbona
authors.affiliation: Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, Castelló, Spain.
authors.forename: R M
authors.initials: RM
authors.lastname: Pérez-Clemente
authors.affiliation: Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, Castelló, Spain.
authors.forename: S I
authors.initials: SI
authors.lastname: Zandalinas
authors.affiliation: Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, Castelló, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Gómez-Cadenas
mesh_terms: D002104:Cadmium / Q000378:metabolism / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002957:Citrus / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D054811:Phytochelatins / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism
chemical_list: D002104:Cadmium; D054811:Phytochelatins; D005978:Glutathione; D002118:Calcium
keywords: Abiotic stress; cadmium toxicity; heavy metal; palliative treatment