Impact of Phytomediated Zinc Oxide Nanoparticles on Growth and Oxidative Stress Response of In Vitro Raised Shoots of Ochradenus arabicus

Abstract

Biogenic nanoparticles have potential roles in the growth and development of plants and animals as they are ecofriendly and free of chemical contaminants. In this study, we assessed the effects of phytomediated zinc oxide nanoparticles (ZnONPs) on shoot growth, biochemical markers, and antioxidant system response in Ochradenus arabicus, which is a medicinal plant. The shoot length and fresh and dry weights were found to be higher in groups with 5 and 10 mg/L ZnONPs than in the control. At high concentrations of ZnONPs (50, 100, and 300 mg/L), biomass was decreased in a concentration-dependent manner. The shoot number was observed to be highest at 50 mg/L among all applied concentrations of ZnONPs. The levels of the stress markers proline and TBARS were found to be higher in shoots treated with 100 and 300 mg/L ZnONPs than in the control as well as NP-treated shoots. The levels of antioxidant enzymes were significantly increased at high concentrations of nanoparticles compared with the control. Thus, synthesized phytomediated ZnONPs from shoots of O. arabicus and their application to the same organ of O. arabicus in vitro were found to be effective as a low concentration of nanoparticles promoted shoot growth, resulting in high biomass accumulation. Thus, using green nanotechnology, such endemic plants could be conserved in vitro and multiple shoots could be produced by reducing the phytohormone concentration for multiple uses, such as the production of potential secondary metabolites.

Effect of Green Synthesized ZnO-NPs on Growth, Antioxidant System Response and Bioactive Compound Accumulation in Echinops macrochaetus, a Potential Medicinal Plant, and Assessment of Genome Size (2C DNA Content)

“…The contents of proline and TBARS were increased in the leaves of E. macrochaetus, which was observed in all treatments with ZnO-NP application. Our result is confirmed according to Al-Qurainy et al [28], as their application of ZnO-NPs on tissue-culture-raised shoots of Ochradenus arabicus enhanced the levels of both proline and TBARS. Similarly, ZnO-NP treatment on Momordica charantia enhanced proline content and up-regulated antioxidant enzyme activity [60].…”

“…The result of Karimi et al [67] showed that low concentrations of NPs have been found to promote plant growth and the production of secondary metabolites. In another study, ZnO-NP treatment enhanced the polyphenolic content in plants [28,48,60]. Similarly, the polyphenolic compounds (lignans and neolignans) were enhanced in cell suspension cultures of Linum usitatissimum under ZnO-NP treatments [29].…”

“…ZnO-NPs were prepared according to the method as followed by Al-Qurainy et al [28] with minor modifications. An amount of 75 mL of freshly prepared Heliotropium bacciferum leaf extract was added into a 0.05 M Zn(NO 3 ) 2 solution at 60 • C and kept at constant stirring overnight.…”

“…In the past few years, ZnO-NPs have received great attention due their ability to improve nutrient accumulation by plants for enhancing the growth, biomass and quality of crops [26,27]. In addition, some reports have described positive aspects of ZnO-NPs regarding their impacts on plant growth, antioxidant system response [28], secondary metabolite production [29] and induction of photosynthetic efficiency [30]. However, high concentrations of ZnO-NPs can be phytotoxic, genotoxic [31] and limit the plant growth and yield.…”

Role of zinc oxide nanoparticles in alleviating sodium chloride-induced salt stress in sweet basil (Ocimum basilicum L.)

“…In addition, at optimum concentrations, it provides a favorable response against abiotic stresses in field plants [20][21][22][23][24][25][26][27][28]. ZnO improves plant tolerance against abiotic stress in various plants by causing in vitro shoot proliferation and boosting various secondary metabolites in Ochradenus arabicus [29]. Positive effects of foliar spraying of ZnO NPs were recorded on plant growth [30,31] in many crop plants under stress, such as eggplant, tomato, brassica, and foxtail millet [26,[32][33][34][35][36] and also studied by Ahmed et al [37], compared with Zn nutrients in tomato plants in detail.…”