Zinc (Zn) is plant micronutrient, which is involved in many physiological functions, and an inadequate supply will reduce crop yields. Its deficiency is the widest spread micronutrient deficiency problem; almost all crops and calcareous, sandy soils, as well as peat soils and soils with high phosphorus and silicon content are expected to be deficient. In addition, Zn is essential for growth in animals, human beings, and plants; it is vital to crop nutrition as it is required in various enzymatic reactions, metabolic processes, and oxidation reduction reactions. Finally, there is a lot of attention on the Zn nanoparticles (NPs) due to our understanding of different forms of Zn, as well as its uptake and integration in the plants, which could be the primary step toward the larger use of NPs of Zn in agriculture. Nanotechnology application in agriculture has been increasing over recent years and constitutes a valuable tool in reaching the goal of sustainable food production worldwide. A wide array of nanomaterials has been used to develop strategies of delivery of bioactive compounds aimed at boosting the production and protection of crops. ZnO-NPs, a multifunctional material with distinct properties and their doped counterparts, were widely being studied in different fields of science. However, its application in environmental waste treatment and many other managements, such as remediation, is starting to gain attention due to its low cost and high productivity. Nano-agrochemicals are a combination of nanotechnology with agrochemicals that have resulted in nano-fertilizers, nano-herbicides, nano-fungicides, nano-pesticides, and nano-insecticides being developed. They have anti-bacterial, anti-fungal, anti-inflammatory, antioxidant, and optical capabilities. Green approaches using plants, fungi, bacteria, and algae have been implemented due to the high rate of harmful chemicals and severe situations used in the manufacturing of the NPs. This review summarizes the data on Zn interaction with plants and contributes towards the knowledge of Zn NPs and its impact on plants.

Potentially toxic elements (PTEs) such as cadmium (Cd), lead (Pb), chromium (Cr), and arsenic (As), polluting the environment, pose a significant risk and cause a wide array of adverse changes in plant physiology. Above threshold accumulation of PTEs is alarming which makes them prone to ascend along the food chain, making their environmental prevention a critical intervention. On a global scale, current initiatives to remove the PTEs are costly and might lead to more pollution. An emerging technology that may help in the removal of PTEs is phytoremediation. Compared to traditional methods, phytoremediation is eco-friendly and less expensive. While many studies have reported several plants with high PTEs tolerance, uptake, and then storage capacity in their roots, stem, and leaves. However, the wide application of such a promising strategy still needs to be achieved, partly due to a poor understanding of the molecular mechanism at the proteome level controlling the phytoremediation process to optimize the plant’s performance. The present study aims to discuss the detailed mechanism and proteomic response, which play pivotal roles in the uptake of PTEs from the environment into the plant’s body, then scavenge/detoxify, and finally bioaccumulate the PTEs in different plant organs. In this review, the following aspects are highlighted as: (i) PTE’s stress and phytoremediation strategies adopted by plants and (ii) PTEs induced expressional changes in the plant proteome more specifically with arsenic, cadmium, copper, chromium, mercury, and lead with models describing the metal uptake and plant proteome response. Recently, interest in the comparative proteomics study of plants exposed to PTEs toxicity results in appreciable progress in this area. This article overviews the proteomics approach to elucidate the mechanisms underlying plant’s PTEs tolerance and bioaccumulation for optimized phytoremediation of polluted environments.

Contamination of agricultural soils with heavy metals present lethal consequences in terms of diverse ecological and environmental problems that entail entry of metal in food chain, soil deterioration, plant growth suppression, yield reduction and alteration in microbial community. Metal polluted soils have become a major concern for scientists around the globe. In more recent times, armed with new knowledge and understanding, removal of heavy metals using different applications has emerged as a solution for waste treatment and contaminant remediation in water and soil. However, the description of metal toxicity to the plants and its removal and degradation from the soil is limited. There are a number of reports in the literature where PGP bacterial inoculation and various chelating agents improves metal accumulation and it’s detoxification in different plant parts without influencing plant growth. Therefore, there is a need to select some useful chemicals which possess the potential to improve plant growth as well as expedite the phytoremediation of metals. In this review, we have discussed the mechanisms possessed by different chelating agents to promote plant growth and phytoremediation of metals. We anticipate that this analysis of interconnected systems will lead to the discovery of new research fields.

High levels of metal(oid)s in soil or food pose a severe health risk to humans. The potential toxicants find their way into the living systems via the food chain, following bioaccumulation in edible plants, including leafy vegetables grown in or irrigated with contaminated soil or water, respectively. The current study determines the levels of vanadium (V), chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), lead (Pb), and cadmium (Cd) in leafy vegetables (rocca, coriander, and parsley) grown in different open irrigated farms in Qatar and investigates their potential human health risks (carcinogenic and noncarcinogenic). The mean concentrations of V, Cr, Ni, Cu, As, Cd, and Pb in rocca are 17.09, 6.41, 1.70, 13.04, 14.72, 0.90, and 6.36 mg/kg, respectively; in coriander are 15.91, 6.03, 1.38, 15.30, 16.86, 0.43, and 5.00 mg/kg, respectively; and in parsley are 16.25, 6.26, 2.19, 17.97, 16.60, 0.51, and 5.46 mg/kg, respectively. The mean levels of V, Cr, As, Cd, and Pb were observed to be higher than the recommended World Health Organization (WHO)/Food and Agriculture Organization (FAO) values. The target hazard quotient (THQ) values of Cu and As were found to be greater than 1 for the adult population. For the two elements (i.e., Cu and As), the THQ varied from 1.03 to 1.42 and 1.17 to 1.44 in men. In women, the values ranged from 1.20 to 1.65 and 1.35 to 1.55, for Cu and As, respectively. The hazard index (HI) of rocca, coriander, and parsley was 3.99, 4.10, and 4.43, respectively, in men, 4.64, 4.76, and 5.14, respectively, among women. The carcinogenic risk (CR) of Cr, Ni, and As ranged from 7.16 × 10⁻⁴ to 7.61 × 10⁻⁴, 5.57 × 10⁻⁴ to 8.85 × 10⁻⁴, and 5.24 × 10⁻³ to 6.01 × 10⁻³, respectively, in men. In women, it ranged from 8.31 × 10⁻⁴ to 8.83 × 10⁻⁴, 6.47 × 10⁻⁴ to 1.03 × 10⁻³, and 6.09 × 10⁻³ to 6.97 × 10⁻³, respectively, in all vegetables. In crux, the consumption of rocca, coriander, and parsley grown in selected farms in Qatar poses a major health risk (both noncarcinogenic and carcinogenic) to the consumer. As a result, we recommend that vegetables grown in the studied areas be closely monitored to protect consumer health.

Grapefruit (Citrus paradisi) is a widely grown citrus and its fruit is affected by a variety of biotic and abiotic stress. Keeping in view the hazardous effects of synthetic fungicides, the recent trend is shifting towards safer and eco-friendly control of fruit diseases. The present study was aimed to diagnose the fruit rot disease of grapefruit and its control by using zinc oxide green nanoparticles (ZnO NPs). Fruit rot symptoms were observed in various grapefruit growing sites of Pakistan. Diseased samples were collected, and the disease-causing pathogen was isolated. Following Koch's postulates, the isolated pathogen was identified as Rhizoctonia solani. For eco-friendly control of this disease, ZnO NPs were prepared in the seed extract of Trachyspermum ammi and characterized. Fourier transform infrared spectroscopy (FTIR) of these NPs described the presence of stabilizing and reducing compounds such as phenols, aldehyde and vinyl ether, especially thymol (phenol). X-ray diffraction (XRD) analysis revealed their crystalline nature and size (48.52 nm). Energy dispersive X-ray (EDX) analysis elaborated the presence of major elements in the samples, while scanning electron microscopy (SEM) confirmed the morphology of bio fabricated NPs. ZnO NPs exhibited very good anti-fungal activity and the most significant fungal growth inhibition was observed at 1.0 mg/ml concentration of green NPs, in vitro and in vivo. These findings described that the bioactive constituents of T. ammi seed extract can effectively reduce and stabilize ZnO NPs. It is a cost-effective method to successfully control the fruit rot disease of grapefruit.