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Modern agriculture involves the use of synthetic compounds (agrochemicals) in order to maximize crop yields. However, inappropriate fertilization and/or the use of pesticides can have adverse effects on crop productivity and quality. In this context, a study has been carried out to ascertain the effect of increasing dosages of a chemical fertilizer (Greenhouse Special) and some widely used pesticides on tobacco plants. To this purpose biomass, chlorophyll contents and the concentration of NO3− and NH4+ were determined. Results showed that NO3− and NH4+ significantly accumulated in tobacco plants following the application of the two the highest fertilizer dosages. Furthermore, some pesticides altered NO3− and NH4+ concentration in leaves. Finally, in order to estimate the effect of these compounds on nitrogen acquisition and metabolism, Nitrogen Use Efficiency was evaluated. Data of NUE evidenced that the optimal dosage of fertilizer was 0.250 g/plant. Moreover, it was found that the active ingredients of pesticides affected NUE in the species studied. [ABSTRACT FROM AUTHOR]

Salinity is one of the most impacting abiotic stresses regarding crop productivity and quality. Among the strategies that are attracting attention in the protection of crops from abiotic stresses, there is the use of plant biostimulants. In this study, Megafol (Meg), a commercial plant biostimulant, was tested on olive plants subjected to severe saline stress. Plants treated with salt alone showed substantial reductions in biomass production, leaf net photosynthesis (Pn), leaf transpiration rate (E), stomatal conductance (gs), and relative water content (RWC). In addition, samples stressed with NaCl showed a higher sodium (Na+) content in the leaves, while those stressed with NaCl and biostimulated with Meg increased the potassium (K+) content in the leaves, thus showing a higher K+/Na+ ratio. Salinity caused the accumulation of significant quantities of hydrogen peroxide (H2O2) and malondialdehyde (MDA) due to decreases in the activity of antioxidant enzymes, namely superoxide dismutase (SOD – EC 1.15.1.1), ascorbate peroxidase (APX – EC 1.11.1.11), guaiacol peroxidase (GPX – EC 1.11.1.9), and catalase (CAT – EC 1.11.1.6). When olive plants under saline stress were biostimulated with Meg, the plants recovered and showed physiological and biochemical traits much improved than salt stressed samples. Finally, Meg exhibited Ca2+-chelating activity in olive pollen grains, which allowed the biostimulant to exert this beneficial effect also by antagonizing the undesirable effects of hydrogen peroxide on Ca2+ metabolism. [ABSTRACT FROM AUTHOR]

Weed control based on herbicides is essential to guarantee high levels of crop productivity. However, these compounds can affect ecosystems and non-target crops. Therefore, a research was carried out in order to investigate the effect of metribuzin (ME) on the capacity of Zea mays L. (maize) to acquire iron (Fe). ME reduced the chlorophyll content, the concentration of phytosiderophores (PSs) released by roots and their Fe content. Both the shoots and roots of ME-treated plants showed increases in ammonia () concentrations. This effect was ascribed to the decreases in the activity of glutamine synthetase (GS; EC 6.3.1.2) and glutamine amide-2-oxoglutarate aminotransferase (GOGAT; EC 1.4.1.14). The results indicate that the interference exerted by ME on nitrogen organication was the cause of the drop in the PSs release and of the reduction in the Fe content. [ABSTRACT FROM AUTHOR]

Abstract Water pollution is becoming alarming since thousands contaminants are dispersed in the aquatic environments, and agricultural practices, for the massive use of pesticides, are contributing to exacerbating this problem. In this context, a research aimed at investigating the ability of duckweed (Lemna minor), a free-floating aquatic species widespread throughout the world, to remediate water polluted with five different concentrations of a herbicide - terbuthylazine (TBA) - was carried out. In addition, duckweed was treated with a plant biostimulant and a safener with the aim of increasing the plant's capacity to tolerate and remove the TBA from the water. The results evidenced that the herbicide affected the duckweed already at the lower concentrations, reducing its capacity to proliferate and the area of its fronds. On the contrary, when the TBA treatments were performed in combination with the biostimulant or the safener the average area of the fronds was affected of lesser extents, compared to the plants treated with the herbicide only. Antioxidant enzymes, namely ascorbate peroxidases (APX) and catalases (CAT), were investigated and it was found that the biostimulated and safened duckweed showed increased activities of these enzymes, compared to the plants treated with TBA only. At last, some phytofiltration experiments were planned. The biostimulated and safened duckweed removed more TBA from polluted water than the plants treated with the herbicide alone. In conclusion, this research showed that duckweed is suitable for cleaning water polluted with TBA and this potential can be successfully improved by treating the species with a biostimulant or a safener. Graphical abstract Unlabelled Image Highlights • Terbuthylazine (TBA) toxicity to duckweed was assessed. • TBA severely affected duckweed especially at the higher concentrations. • The effects of a biostimulant and a safener on duckweed were investigated. • Biostimulant and safener reduced TBA toxicity to the species. • Biostimulated and safened plants adsorbed higher amounts of TBA from polluted water. [ABSTRACT FROM AUTHOR]

BACKGROUND Safeners are agrochemicals used in agriculture to protect crops from herbicide injuries. They act by stimulating herbicide metabolism. As graminaceous plants, to cope with iron (Fe) deficiency, activate sulfur (S) metabolism and release huge amounts of Fe-chelating compounds, or phytosiderophores ( PSs), we investigated, in barley plants ( Hordeum vulgare, L.) grown in Fe deficiency, the effects of three safeners on two enzymes of S assimilation, cysteine (Cys) and glutathione ( GSH), and PS release. Finally, we monitored the root Fe content in plants treated with the most effective safener. RESULTS Generally, all the safeners activated S metabolism and increased Cys and GSH contents. In addition, the safened plants excreted higher levels of PSs. Given that mefenpyr-diethyl (Mef) was the most effective in causing these effects, we assessed the Fe concentration in Mef-treated barley and found higher Fe levels than those in untreated plants. CONCLUSION The three safeners, in different ways but specifically, activated S reductive metabolism and regulated Cys and GSH contents, PS release rate and Fe content (Mef-treated barley). The results of this research provide new indications of the biochemical and physiological mechanisms involved in the safening action. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]