Interaction of bioaccumulation of heavy metal chromium with water relation, mineral nutrition and photosynthesis in developed leaves of Lolium perenne L

• Published in: Chemosphere (Oxford) 2007-07, Vol.68 (8), p.1563-1575
• Main Authors: Vernay, Philippe, Gauthier-Moussard, Cécile, Hitmi, Adnane
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Chlorophyll - analysis; Chromium; Chromium - analysis; Chromium - pharmacokinetics; Chromium - toxicity; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Fundamental and applied biological sciences. Psychology; Lolium - drug effects; Lolium - growth & development; Lolium - metabolism; Lolium perenne; Lolium perenne L; Mineral nutrient content; Minerals - analysis; Nutritional Physiological Phenomena; Photochemical reactions; Photosynthesis - drug effects; Photosynthetic electron transport; Plant Leaves - drug effects; Plant Leaves - growth & development; Plant Leaves - metabolism; Soil Pollutants - analysis; Soil Pollutants - pharmacokinetics; Soil Pollutants - toxicity; Water - analysis; Water status
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2007.02.052

Contamination by chromium (Cr) is widespread in agricultural soils and industrial sites. This heavy metal represents a risk to human health. In order to gain fundamental insights into the nature of the adaptation to Cr excess, the characterisation of physiological indices, including responses of photosynthetic gas exchange and chlorophyll a fluorescence along with changes in mineral nutrient contents and water status were studied in ray grass ( Lolium perenne L.). Increased concentrations of Cr(VI) (0–500 μM Cr) in the Coïc and Lessaint nutrient solution were applied. The growth of Lolium perenne is decreased by chromium and the leaves have lost their pigments. Chromium accumulation was greater in roots than in leaves and reached 2450 and 210 μg g −1 DW, respectively with 500 μM Cr(VI) in nutrient medium. The physiological parameters were severely reduced by this heavy metal. Cr induced toxicity arising from 100 μM Cr(VI) and resulted in a modification of mineral content in roots and leaves, especially for Ca, Mg and Fe. The chromium stress decreased CO 2 assimilation rates mainly due to stomatal closure, which reduced water loss by transpiration without decreasing the cellular available CO 2. The fluorescence parameters associated with photosystem II (PSII) activity and the photochemical activity are modified by chromium. Non-radiative energy dissipation mechanisms were triggered during stress since non-photochemical quenching was increased and efficiency of excitation capture by open centers was reduced.