کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2055788 | 1543902 | 2015 | 10 صفحه PDF | دانلود رایگان |
The presence of Psidium guajava in polluted environments has been reported in recent studies, suggesting that this species has a high tolerance to the metal stress. The present study aims at a physiological characterization of P. guajava response to high nickel (Ni) concentrations in the root-zone. Three hydroponic experiments were carried out to characterize the effects of toxic Ni concentrations on morphological and physiological parameters of P. guajava, focusing on Ni-induced damages at the root-level and root ion fluxes. With up to 300 μM NiSO4 in the root-zone, plant growth was similar to that in control plants, whereas at concentrations higher than 1000 μM NiSO4 there was a progressive decline in plant growth and leaf gas exchange parameters; this occurred despite, at all considered concentrations, plants limited Ni2+ translocation to the shoot, therefore avoiding shoot Ni2+ toxicity symptoms. Maintenance of plant growth with 300 μM Ni2+ was associated with the ability to retain K+ in the roots meanwhile 1000 and 3000 μM NiSO4 led to substantial K+ losses. In this study, root responses mirror all plant performances suggesting a direct link between root functionality and Ni2+ tolerance mechanisms and plant survival. Considering that Ni was mainly accumulated in the root system, the potential use of P. guajava for Ni2+ phytoextraction in metal-polluted soils is limited; nevertheless, the observed physiological changes indicate a good Ni2+ tolerance up to 300 μM NiSO4 suggesting a potential role for the phytostabilization of polluted soils.
Journal: Journal of Plant Physiology - Volume 174, 1 February 2015, Pages 137–146