Silicon Nanoparticles More Efficiently Alleviate Arsenate Toxicity than Silicon in Maize Cultiver and Hybrid Differing in Arsenate Tolerance

Abstract

Alleviation of abiotic stress by silicon (Si) is well documented. But mitigation of abiotic stress by silicon nanoparticles (SiNPs) is not much known. Therefore, hydroponic experiments were conducted to investigate if SiNPs are more effective than Si in mitigation of arsenate (As V ; 25 and 50 µM) toxicity in maize cultivar and hybrid differing in As V tolerance. Under As V stress, reduction in growth was accompanied by enhanced level of As and oxidative stress. As V inhibited activities of antioxidant enzymes like ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase (except superoxide dismutase). The redox status of ascorbate and glutathione was disturbed by As V as indicated by a steep decline in their reduced/oxidized ratios. However, addition of Si and SiNp ameliorates As V toxicity in maize. Si and SiNp both could reduce As V toxicity in maize cultivar and hybrid, which could be related with decreased accumulation of As and oxidative stress, and enhanced components of the ascorbate-glutathione cycle (AsA-GSH cycle). But lowering in the accumulation of As and oxidative stress markers, and enhancement in components of the AsA-GSH cycle was prominent in SiNp fed seedlings under As V stress. The results also showed that SiNp are more effective in reducing As V toxicity than Si, which is due to their greater availability to seedlings. Comparing responses of cultivar and hybrid, maize cultivar shows more resistance against As V than hybrid.

Silicon enhancement of estimated plant biomass carbon accumulation under abiotic and biotic stresses. A meta-analysis

“…Coprecipitation of toxic cationic metals with plant-available Si and adsorption of toxic anionic metals on the iron plaques are the major mechanisms for Si to mediate the alleviation of heavy metal toxicity in soils (Liang et al 2005b;Gu et al 2011;Adrees et al 2015;Wu et al 2016b). In addition, Si deposition in the roots is the primary inhibitory effect on apolasmic transport of Na + across the roots (Gong et al 2006), while monosilicic acid competition with arsenite can reduce plant arsenic uptake under anaerobic conditions Tripathi et al 2013;Marmiroli et al 2014;Tripathi et al 2016a). Furthermore, Si-mediated alleviation of heavy metal toxicity also occurs in root cells and xylem vessels (Liang et al 2007;Lukačová et al 2013;Ma et al 2014).…”

Acquisition and Homeostasis of Iron in Higher Plants and Their Probable Role in Abiotic Stress Tolerance

“…Plants, being the most precious gift of the nature that fulfill several basic requirements of human beings, are severely affected by various abiotic stress factors. Abiotic stress causes significant reduction in growth and yield of plants via inducing oxidative stress through enhanced reactive oxygen species (ROS) production and by lowering the antioxidant activities, level of nutrients, and modification of anatomical structures (Nagajyoti et al, 2010;Nazar et al, 2012;Vaculík et al, 2012;Singh et al, 2015;Tripathi et al, 2016bTripathi et al, , 2017a. Hoagland and Arnon (1950) pioneered the most popular and commercial technique for developing plants with their roots in solutions containing mineral nutrients required for the growth of plants.…”

Silicon (Si) biochar for the mitigation of arsenic (As) bioaccumulation in spinach ( Spinacia oleracean ) and improvement in the plant growth

“…However, given the relatively low bioavailability of Si in these biochars from Si bioaccumulators, its influence on heavy metal remediation is minimal (Tripathi et al, 2016). The synthesis of Si-modified biochars (containing intentionally elevated concentrations of Si) aimed at remediating heavy metals in soil, is a novel modification approach that has received very little attention.…”