Fertilizer ApplicationFertilizer Application. Dr. VoisinAndré. Pp. xiv + 108, with figures and tables. Crosby Lockwood & Son Ltd., London. 18s.

The cytotoxicity assessment of nanomaterials has become a global concern for diverse disciplines, including agriculture. This study explored the physiological and molecular responses of pepper seedlings to the foliar application of copper nanoparticles (CuNPs; 50, 100, and 200 mg L−1) compared to the bulk control. The CuNPs treatment at 50 mg L−1 increased the shoot biomass by 20%, whereas the treatments at concentrations above 100 mg L−1 adversely influenced biomass (25%), chlorophyll content (21%), and starch concentration (23%). Moreover, the CuNPs treatments at the toxic doses increased H2O2 concentration (60%) and lipid peroxidation levels (27%), implying oxidative stress and potentially impaired membrane integrity. However, the phytotoxicity risk associated with the CuNPs application was lower than the bulk control. The CuNPs treatments upregulated the activities of catalase (2-folds), peroxidase (85%), and polyphenol oxidase (70%). The toxic doses of CuNPs increased the protease activity by 16%. The Cu supplementation influenced the transcription of microRNA159 (miR159) and Mevalonate kinase (MVK) genes in concentration and material type-dependent manners. Toxic concentrations of CuNP transcriptionally upregulated miR159 by approximately 2-folds. The expression of the MVK gene displayed a downregulation trend (5-folds) in response to the bulk Cu, while the CuNPs treatments slightly downregulated this gene. With increasing the concentration of CuNPs, the accumulations of protein and non-protein thiols displayed an increasing trend by approximately 45%. The CuNPs-treated plants contained a higher concentration of proline (59%) and phenols (34%). This study underlines the potential cytotoxicity risk associated with the application of CuNPs as a fertilizer or pesticide in agriculture-related industries.

Copper nanoparticles mediated physiological changes and transcriptional variations in microRNA159 (miR159) and mevalonate kinase (MVK) in pepper; potential benefits and phytotoxicity assessment

Impact of nanoparticles and their ionic counterparts derived from heavy metals on the physiology of food crops

Mineral nutrients play a significant role in plant growth and development. However, a large number of elements are required for the growth of plants. Visual deficiency symptoms are generally characteristic enough to permit easy identification of the deficiency of a nutrient, as these appear on particular plant parts at specific growth stage(s). Micronutrients play many complex roles in plant nutrition. While most of the micronutrients participate in the functioning of a number of enzyme systems, there is considerable variation in the specific functions of the various micronutrients in plant and microbial growth processes. For example, copper, iron, and molybdenum are capable of acting as electron carriers in the enzyme systems that bring about oxidation reduction reactions in plants. Vegetable crops are generally sensitive to high zinc levels, while grasses usually tolerate high levels of available soil zinc. Nutrients can be absorbed through plant leaves.

Micronutrients Deficiency in Vegetable Crops and Their Management

Polysaccharides combined to copper and magnesium improve tomato growth, yield, anti-oxidant and plant defense enzymes

Sandy soils with high alkalinity are characterized by low copper (Cu) contents that lead to many deficiency symptoms in plants. Cu deficiency in plants can be corrected using several cheap Cu sources. Nevertheless, the effects that novel sources, such as Cu nanoparticles (NPs), have on plants remain poorly studied. In the present work, we investigated the effect and efficiency of Cu supplementation to onion (Allium cepa L.) plants using Cu sulfate, chelate, or NPs, and compared their effects on bulb quality, yield, and contents of phytochemicals. Two successive seasons (2018/2019 and 2019/2020) of field experiments were conducted in newly reclaimed sandy soils, where plants were sprayed with either 10 ppm CuO NPs, 20 ppm CuSO4·5H2O, or 20 ppm of Cu chelates. Overall, Cu deficiency (control) resulted in a significant decrease in yield and all quality traits of onion plants. CuO NPs treatment significantly enhanced growth parameters, including plant height, number of leaves, fresh and dry weight, yield, and bulb quality, compared with Cu sulfate and chelates. This was also the case regarding chemical constituents such as macro- and micro-nutrients, total soluble solids, phytochemical compounds, vitamins, and amino acids. Although Cu sulfate is the cheapest form used for Cu supplementation, results of the present study suggest that CuO NPs was not only safe to use, but also was the treatment that led to the highest onion yield and quality.

Ahmed Z. A. Hassan

Papers

Are Copper Nanoparticles Toxic to All Plants? A Case Study on Onion (Allium cepa L.)