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The current work investigates the capacity of the water primrose ( Ludwigia stolinefera ) to sequester inorganic and organic nutrients in its biomass to restore eutrophic wetlands, besides its nutritive quality as fodder for animals. The nutrient elements and nutritive value of the water primrose were assessed seasonally in polluted and unpolluted watercourses. The water primrose plants’ highest biomass was attained during summer; then, it was significantly reduced till it reached its lowest value during winter. In the polluted canal, the plant root and shoot accumulated higher contents of all nutrient elements (except Na and Mg) rather than in the unpolluted Nile. They accumulated most investigated nutrients in the growing season during summer. The shoots accumulated higher contents of N, P, Ca, and Mg than the root, which accumulated higher concentrations of Na and K. Therefore, summer season is the ideal time to harvest water primrose for removing the maximum nutrients for restoring eutrophic watercourses. The aboveground tissues had the highest values of ether extract (EE) during spring and the highest crude fibers (CF) and total proteins (TP) during summer. In contrast, the belowground tissues had the lowest EE, CF, and TP during winter. In spring, autumn, and winter seasons, the protein content in the grazeable parts (shoots) of the water primrose was within the range, while in summer, it was higher than the minimum requirement for the maintenance of animals. There was a decrease in crude fibers and total proteins, while an increase in soluble carbohydrates content in the below- and above-ground tissues of water primrose under pollution stress. The total protein, lipids, and crude fibers of the aboveground parts of water primrose support this plant as a rough forage.

Lower concentrations of nanoparticles (NPs) could have positive effects on plants. In the present experiment, we tested the efficacy of seed priming Egyptian roselle cultivar with aluminum oxide nanoparticles (Al2O3 NPs). Plants grown with different concentrations (0.01, 0.05, 0.1, and 0.5%) of Al2O3 NPs-primed seeds showed varied responses. An increasing impact with 0.01% Al2O3 NPs was noticed on growth traits, such as fresh weight, dry weight, shoot length, root length, and leaf area, and physio-biochemical activities like chlorophyll a, chlorophyll b, carotenoid contents, soluble sugars, protein, amino acid, proline, and the activities of defense enzymes viz-superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). Nevertheless, a decrease was noted in malondialdehyde (MDA) when plants were primed with 0.01% Al2O3 NPs. Seed priming with 0.05, 0.1, and 0.5% Al2O3 NPs caused the negative effects in the aforementioned parameters. The principal component analysis revealed significant correlations among the various studied parameters. Therefore, seed priming with Al2O3 NPs at 0.01% was expected to serve as an effective measure for inducing positive effect in Egyptian roselle cultivar.

Copper (Cu) is a micronutrient that assumes a principal role in plant growth and development. However, its excess concentration in soil is imperiling crop productivity. Inoculation with different bacterial strains in cereals could modify growth traits, photosynthetic effectiveness, and generation of strong antioxidant defense systems to make them more tolerant of Cu stress. Therefore, a pot study was designed to test plant growth-promoting rhizobacteria (PGPR) including Paenibacillus polymyxa and Bacillus circulans to Cu exposed maize (Zea mays L.) plants. Increasing Cu (100 to 500 µM of CuSO4) concentration decreased growth traits, photosynthetic pigments, soluble sugars, phosphorous (P) and potassium (K) contents, and the activity of catalase (CAT) but increased proline and malondialdehyde (MDA) content, the activity of peroxidase (POD) and Cu ions at root and shoot level. Moreover, the bacterial treatment also modulated the antioxidant capability in stress-free plants. Nevertheless, inoculation with P. polymyxa and B. circulans alleviated Cu-induced growth, photosynthetic pigments and mineral nutrient (P and K) on one hand and regulating the pools of osmolytes and antioxidant enzymes, whilst simultaneously reducing MDA and Cu root and shoot contents. These improved activities of antioxidant enzymes and the regulation of osmolytes content elicited by the blend of bacterial inoculation would have retained the ability of maize plants to confer resilience to Cu stress. This study further affirms that the application of two specific bacterial strains to maize plants proved very effective to ameliorate the Cu toxicity.