Effects of nZnS vs. nZnO and ZnCl2 on mungbean [Vigna radiata (L.) R. Wilczek] plant and Bradyrhizobium symbiosis: A life cycle study.

Scarce of knowledge of using Zinc (Zn) nanoparticles (NPs) to augment plant growth, Zn availability to plants and its potential toxicity warrants more NPs-plant life cycle studies. The main objectives of this study were to compare nano zinc sulphide (nZnS) with nano zinc oxide (nZnO) and ionic Zn i.e., ZnCl2, as a source of Zn, as well as to establish physiological impact of NPs on growth, yield and symbiosis of mungbean [Vigna radiata (L.) R. Wilczek] plants at different concentrations (0, 0.01, 0.1, 1 and 10 mg kg-1 of soil). In this study, mungbean plants were grown for 60 days (life cycle study) in natural soil infested with Bradyrhizobium. Effects of Zn compounds (nZnS, nZnO and ZnCl2) on plant height, dry biomass, number of nodules per plant, yield and fruit agronomical parameters along with micronutrient assessment were determined. Impact of Zn compounds on Bradyrhizobium-mungbean symbiosis was also unravelled. Results showed that both the NPs, (nZnS and nZnO) were more effective than ZnCl2 in promoting growth and yield up to a critical concentration and above which phytotoxic effects were observed. Both the NPs were more effective than ZnCl2 at increasing fruit Zn content also. Whereas, nZnS treatment was found to be better than nZnO in improving overall plant growth. Bradyrhizobium-mungbean symbiosis was not affected at lower NPs concentrations, while higher concentration revealed toxicity by damaging bacterial morphology and nodule formation. There was no nano specific toxicity found while, ZnCl2 showed relatively more toxicity than both the NPs. The present investigation demonstrated the concept of nano-micronutrient as well as NPs phytotoxicity by understanding NPs-plant interactions in the soil environment.

Zinc sulphide nanoparticle (nZnS): A novel nano-modulator for plant growth.

In spite of extraordinary properties of zinc sulphide nanoparticle (nZnS), its role on plant system is not well understood, yet. Therefore, this study was aimed to assess the uptake, translocation and effects of nZnS in mung bean (Vigna radiata) plant at 0, 0.1, 0.5 and 1 mg L-1 concentrations. In this study, nZnS was synthesized by modified reflux method and physicochemical characterizations were conducted. The effects of nZnS on mung bean plant were determined by seed germination, growth parameters, membrane integrity and ROS-antioxidant defense assays. Our results showed that nZnS treatment has significantly increased seed germination, root-shoot length, pigment content and decreased lipid peroxidation. There were increased total antioxidant activity (TAA), DPPH and flavonoid contents found in treated plants. Also, nZnS treatment did not activate oxidative stress determined by SOD, CAT, CPX, APOX and GR activities. The uptake and translocation of nZnS in mung bean plants were determined by Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM), revelling that nZnS localized primarily in the vacuoles and chloroplasts. Besides, electron micrographs showed no alteration in cell structures between treated and control plants, further confirming that nZnS treatment has no phytotoxic effects. In vitro and in vivo studies on Zn release from nZnS were also determined using Inductively Coupled Plasma Mass Spectroscopy (ICPMS) and Energy Dispersive X-ray (EDX), which showed that the Zn release and particles uptake were concentration dependent. Overall, results of this study demonstrated the positive role of nZnS on growth and antioxidant defense responses in V. radiata at the experimental concentrations.

Nanohexaconazole: synthesis, characterisation and efficacy of a novel fungicidal nanodispersion.

Here, the authors describe a simple method to formulate the nanodispersion of hexaconazole (hexa); henceforth, referred to as nanohexaconazole (N-hexa) that is water soluble and effective against several species of Aspergillus. Size and shape of the prepared nanocomposite was determined with high-resolution transmission electron microscopy and field-emission scanning electron microscopy. Nanohexaconazole structure was further confirmed by Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry. The antifungal efficacy of nanohexaconazole (N-hexa) was studied in vitro, compared with micronised hexaconazole (M-hexa) at different doses (5 ppm, 10 ppm and control) against two food pathogenic fungi: Aspergillus niger (MTCC 282, MTCC 2196 and BDS 113) and Aspergillus fumigatus through poisoned food technique. A dose-dependent significant growth inhibition was observed in nanohexaconazole (N-hexa) treated fungal sample compared with that of micronised hexaconazole (M-hexa). Micrographic studies for the morphological analysis of control and nanohexaconazole (N-hexa) treated fungal samples were done, exhibited an alternation in fungal morphology. Results showed that nanohexaconazole (N-hexa) is more efficacious than commercially available micronised hexaconazole (M-hexa). In future nanohexaconazole (N-hexa) could be a possible candidate for modern medical science and also reduce damage to the environment from injudicious use of pesticides.