Physiological and biochemical responses of sunflower (Helianthus annuus L.) exposed to nano-CeO2and excess boron: Modulation of boron phytotoxicity.
Little is known about the interaction of nanoparticles (NPs) with soil constituents and their effects in plants. Boron (B), an essential micronutrient that reduces crop production at both deficiency and excess, has not been investigated with respect to its interaction with cerium oxide NPs (nano-CeO2). Considering conflicting results on the nano-CeO2toxicity and protective role as antioxidant, their possible modulation on B toxicity in sunflower (Helianthus annuus L.) was investigated. Sunflower was cultivated for 30 days in garden pots containing original or B-spiked soil amended with nano-CeO2at 0-800 mg kg-1. At harvest, Ce and B concentrations in tissues, biomass, and activities of stress enzymes in leaves were determined. Results showed that in the original soil, Ce accumulated mainly in roots, with little translocation to stems and leaves, while reduced root Ce was observed in plants from B-spiked soil. In the original soil, higher levels of nano-CeO2reduced plant B concentration. Although morphological effects were not visible, changes in biomass and oxidative stress response were observed. Sunflower leaves from B-spiked soil showed visible symptoms of B toxicity, such as necrosis and chlorosis in old leaves, as well as an increase of superoxide dismutase (SOD) activity. However, at high nano-CeO2level, SOD activity decreased reaching values similar to that of the control. This study has shown that nano-CeO2reduced both the B nutritional status of sunflower in original soil and the B phytotoxicity in B-spiked soil.
Institute of Ecosystem Studies, National Research Council (ISE-CNR), Via Moruzzi, 1 - 56124, Pisa, Italy. Electronic address: eliana.tassi@ise.cnr.it.
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Tassi
Institute of Agricultural Biology and Biotechnology, National Research Council (IBBA-CNR), Via Moruzzi, 1 - 56124, Pisa, Italy.
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Giorgetti
Biophysics Institute, National Research Council (IBF-CNR), Via Moruzzi, 1 - 56124, Pisa, Italy.
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Morelli
Chemistry Department, The University of Texas at El Paso, 500 West Univ. Av., El Paso, TX 79968, United States; Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968, United States; Center for Environmental Implications of Nanotechnology, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968, United States.
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Peralta-Videa
Chemistry Department, The University of Texas at El Paso, 500 West Univ. Av., El Paso, TX 79968, United States; Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968, United States; Center for Environmental Implications of Nanotechnology, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968, United States.
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Gardea-Torresdey
Institute of Ecosystem Studies, National Research Council (ISE-CNR), Via Moruzzi, 1 - 56124, Pisa, Italy.
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Barbafieri
D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D001895:Boron / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D002374:Catalase / Q000378:metabolism; D002563:Cerium / Q000737:chemistry*; D006368:Helianthus / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D018515:Plant Leaves / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D018521:Plant Physiological Phenomena / Q000187:drug effects*; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D018520:Plant Shoots / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D010940:Plant Proteins; D012987:Soil; D012989:Soil Pollutants; D002563:Cerium; C030583:ceric oxide; D002374:Catalase; D013482:Superoxide Dismutase; D001895:Boron
Boron interaction; Ce uptake; Growth parameters; Helianthus annuus; Nano-CeO(2); Oxidative stress; Toxicity symptoms