Physiological and biochemical responses of sunflower (Helianthus annuus L.) exposed to nano-CeO2 and excess boron: Modulation of boron phytotoxicity

Abstract

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-CeO). Considering conflicting results on the nano-CeO toxicity 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-CeO at 0-800 mg kg. 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-CeO reduced 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-CeO level, SOD activity decreased reaching values similar to that of the control. This study has shown that nano-CeO reduced both the B nutritional status of sunflower in original soil and the B phytotoxicity in B-spiked soil.

An integrated approach to highlight biological responses of Pisum sativum root to nano-TiO2 exposure in a biosolid-amended agricultural soil

“…In such complex matrices, the bioavailability of the different NPs often is not predictable, due to their tendency to aggregate, to adsorb/precipitate on solid phase, as well as to be coated by organic molecules (Tourinho et al 2012;Pachapur et al 2016). In addition, the overall picture of their possible interactions with crop plants and with food chains are not at all clear (Ruffini Castiglione and Cremonini 2009;Remedios et al 2012;Rico et al 2011;Tassi et al 2017). Given that we can not afford to miss the opportunity of exploiting nanotechnologies, it is priority and urgent to dispel these uncertainties, that nowadays remain, about the possible harmful effects of these nanomaterials, otherwise transferred in farming soils, on crop plants and food chains.…”

Elucidating the mechanisms for plant uptake and in-planta speciation of cerium in radish (Raphanus sativus L.) treated with cerium oxide nanoparticles

“…It is well recognized that the release of cerium oxide nanoparticles (CeO 2 NPs) into the environment could pose serious risks to human health due to their potential accumulation in food crops [1,2]. Previous investigations have shown that CeO 2 NPs could be taken up by radish (Raphanus sativus L) and many other agricultural crops [3][4][5][6][7][8] and the health risks associated with the foodborne Ce depend on the physicochemical properties of Ce in plant tissues [9,10]. A few previous studies reported that Ce in plant tissues remained as CeO 2 NPs after plant uptake [11,12].…”

Cerium Oxide Nanoparticles Affect Heavy Metals Uptake by Pea in a Divergent Way than Their Ionic and Bulk Counterparts

“…,Tassi et al (2017),Zhang et al (2017),Salehi et al (2018) andRamírez-Olvera et al (2018), respectively. However, to our knowledge, this is the first experimental work on the heavy metal uptake by pea originated by emerging nanopollutants.…”