The present work evaluated the effect of soil (S) and foliage (F) applied potassium on the growth, yield, and quality of potato plants. Potassium was added in soil at the recommended rate for all the treatments combining mineral fertilizers with K-feldspar and biofertilizers, while foliar spraying included the application of potassium citrate (PC), potassium silicate (PS), and monopotassium phosphate (MP). The obtained results showed that plant height was highest following treatment with 100% mineral potassium fertilizer under the foliar application of MP, while the content of P, K, and total carbohydrates in leaves also increased with the same fertilization treatment. On the other hand, the highest values for number of stems and fresh and dry weight per plant, as well as the highest nitrogen content in leaves, were obtained after the addition of mineral potassium fertilizer and the foliar spraying of PC, regardless of the growing season. Yield parameters were positively affected by the combination of mineral potassium fertilizers (100% or 80% K₂SO₄ + 20% K-feldspar + biofertilizer) and the foliar spraying of MP, while the total nitrogen, protein, amino acids, potassium, phosphorus, and starch content of tubers were positively affected by the same mineral fertilizer treatments combined with foliar spraying of MP or CP. In conclusion, the application of mineral potassium fertilizer with foliar spraying of MP or CP increased most of the plant growth- and tuber chemical composition-related parameters. These results highlight the importance of potassium fertilizer regimes for achieving high tuber yields and improving the quality of tubers in a sustainable and cost-effective manner.

Chia (Salvia hispanica L.) is a specialty crop capable of providing healthy food and metabolites. The goal of our study was to explore the possibility of expanding seed yield, oil production, and metabolites of chia in response to amino acid, barthenosteriode, and algae extract treatments used as bio-stimulants. The experiment was conducted in the field in a randomized complete block design with three repeats. The treatments were (1) control (spray only with water), (2) amino acids with nutrients (2 mL/L vs. 4 mL/L), (3) brassinolide (5 mL/L vs. 10 mL/L), and algae extract (2 mL/L vs. 4 mL/L). The growth and yield measurements of chia, such as chlorophyll, carotenoids, amino acids, indoles, phenols, macro- and micronutrients, carbohydrates, total oil, and fatty acids were analyzed. The chia plants sprayed with growth stimulant materials showed increases in most studied characteristics, particularly algae extract at 4 mL/L, followed by algae extract at 2 mL/L during the first and second seasons. Meanwhile, amino acids at 4 mL/L led to the third-highest increases in most cases. Conversely, all bio-stimulant treatments decreased total phenols in leaves (mg/100 g f.w.), especially seaweed at 4 mL/L, compared to high levels in the control during both seasons. Control plants showed the lowest levels of the measurements mentioned previously when scored by barthenosteriode at 5 mL/L during the first and second seasons. GLC for fixed oil in chia showed the recognition of four biocomponents. i.e., oleic, linoleic, palmitic, and α-α linolenic acids. The main biocomponent was α-α linolenic acid and reach (49.7 to 57.9%). The application of seaweed at 4 mL/L could be exploited to improve growth, seed crop, fixed oil production, chemicals and bio-constituents, especially the fixed oil composition of chia (Salvia hispanica L.) plant.

The aim of this study was to evaluate some physiological parameters and biochemical changes in common bean plants (Phaseolus vulgaris) as a result of the foliar spraying of some nano stimulants (silicon, polyamine, seaweed and biofertilizer) under salt stress conditions. The pot experiment was conducted in the Agriculture Faculty's greenhouse at Menoufia University in Shibin El-Kom, Egypt during the two summer seasons of 2019 and 2020. Salt stress at level 6 dS/m significantly decreased growth, physiological characteristics, photosynthetic pigments, chemical measurements, and yield parameters. Meanwhile, the use of nano stimulators reduced the adverse effects of salinity by improving water relations, chlorophyll, enzymatic antioxidants (peroxidase and polyphenoloxidase), non-enzymatic antioxidants defense system (carotene, total soluble sugars, total amino acids, and proline), N, P and K and decreased Na+ concentrations resulted in high seed yield, particularly with nano silicon followed by nano biofertilizer. As the level of salinity increased, the seed weight (g/plant) decreased significantly by about 40% at the salt level 6 dS/m. In comparison to the control, using nano silicon resulted in significant increases in the leaf area, relative water content, proline concentration and seed weight by about 84, 53, 49 and 91%, respectively at 6 dS/m salinity level. To mitigate the negative impacts of salinity and improve the production, this study suggests spraying common bean plants with nano silicon followed by nano biofertilizer.

This work assessed the alleviating effects of bacteria ( Bacillus subtilis ) and phosphorus as environmentally friendly materials on the cultivation of pepper plants in polluted soil with lead (Pb) in forms of PbSO ₄ , and Pb(NO ₃ ) ₂ at rates of 0, 1000, 2000 and 3000 µg Pb/g soil. Pot experiments were conducted to study the growth parameters, some physiological factors, biochemical constituents, and yield attributes, as well as the tolerance index (TI), translocation factor (TF), bioconcentration factor (BCF), and health effects [daily intake of heavy metals (DIM), health risk index (HRI), and carcinogenic risk (CR)]. Increasing the Pb concentration of all Pb salt used in soil severely affected the plant vegetative growth parameters. In comparison with other Pb salt forms, Pb(NO ₃ ) ₂ salt had a strong inhibitory impact. Additionally, the photosynthetic pigments in leaves were negatively impacted by all Pb salt forms. The application of Pb in all salt forms led to changes in the leaf water deficit (LWD), osmotic pressure, and membrane integrity and decreased the total water content, relative water content (RWC), transpiration rate, and leaf succulence. Pollution with Pb salts considerably decreased the yield constituents and various chemical properties of pepper, more so in the presence of Pb nitrate than in the presence of Pb sulfate type. A comparison of the concentration of Pb presence of Pb nitrate was greatly increased than the Pb sulfate in the whole plants. The safe limit of 0.3 mg/kg was exceeded by the Pb concentration in pepper fruits (6.3 and 4.3 mg/kg) cultivated in Pb-contaminated soil [with Pb(NO ₃ ) ₂ and PbSO ₄ , respectively]. Additionally, Pb sulfate had a greater detrimental effect on Pb uptake in several plant organs than other Pb salt forms. The TI of pepper plants treated with salt types was >60% with PbSO ₄ (75.6%), whereas it was shoots (TFsh) > fruits (TFf), with TF values < 1. When compared with TFr and TFsh, TFs for shoot to fruits (TFf) had the lowest values (range, 0.07–0.22). The DIM, HRI, and CR values of pepper plants revealed that the Pb of fruit of stressed pepper plants is within safe limits. In addition to reducing the detrimental effects of intolerable Pb levels (2000 and 3000 µg Pb/g soil) on the majority of the aforementioned characters, adding Bacillus bacteria as a bio-agent and phosphorus as a chemo-agent to Pb-polluted soils also stimulated growth, increased yield, controlled plant water relations, protected photosynthetic pigments, and sharply decreased the Pb accumulation in plant organs. The Bacillus bacteria application resulted in some superior characteristics, such as root length, leaf number, leaf length, leaf area, leaf area index, fresh biomass, dry biomass, photosynthetic pigments, quantity yield attributes, reduction Pb accumulation in all plant organs, TI, TFr, TFf, BCF, in health effects trials, whereas phosphorus application improved plant height, leaf width, RWC, LWD, osmotic pressure, total soluble solids, acidity, total carbohydrates, total protein, and TFsh.

Additional fertilization with actosol macroelements, actosol microelements and/or compost; significantly reduced the incidence of onion downy mildew disease(ODM) on both tested onion cultivars (Giza 6 and Giza 20). Increasing the fertilizer dose gave more disease reduction and improved growth characteristics, photosynthetic pigments, water relations and yield production. Generally, the best results were obtained when actosol macroelements (10 ml/l) was applied. Application of plant water extracts on onion plants at intervals of 15 days, significantly decreased the infection with the fungus. Both of neem or mint plant extracts at conc. 10 % showed the best results for disease reduction, growth characteristics, photosynthetic pigments, water relations and yield production. The best yield production was obtained by the application of actosol macroelements and /or neem plant extract.

Pot experiments were conducted in a greenhouse with the aim to study the role of antioxidant ascorbic acid under two levels (0 and 100 ppm) in minimizing and/or overcoming the phytotoxic effects of H2S (0, 50 and 100 ppm) on growth characters, some physiological and biochemical aspects; and yield quantity and quality parameters of lettuce plants. Vegetative growth parameters of H2S-polluted lettuce plants were significantly reduced with increasing the H2S level. The phytotoxic effect of H2S at the high level was more pronounced and greater in head length (-31%), stem length (-34%), leaf area (-42%), fresh whole plant (-35%) and dry whole plants (-34%) matters of lettuce plant than other growth characters. Treating the H2S- polluted lettuce plants with ascorbic acid not only counteracted the harmful effect on the above-mentioned parameters, but also induced a greatly increase in them, head length (40%), stem length (104%), leaf area (82%), fresh whole plant (148%) and dry whole plant (96%) matters compared with the untreated plants. Leaf water deficit (LWD), osmotic pressure and membrane integrity (MI) were increased, whereas total water content (TWC), relative water content (RWC), transpiration rate, and the administration of H2S reduced the succulence of the leaves. Using ascorbic acid led to regulate and improve the plant water status by increasing RWC (66%) and osmotic pressure (16%), and decreasing LWD (40%), and MI (28%). All H2S levels had a deleterious effect on leaf photosynthetic pigments; chlorophyll a, b and total chlorophylls, carotenoids, total photosynthesis as well as chlorophyll stability index (CSI). Application of ascorbic acid overcame the inhibitory effect of H2S and enhanced the biosynthesis and concentration of photosynthetic pigments; chl. a (170%), chl. b (303%), total chlorophyll (186%) as well as carotenoids (64%). Exposure of lettuce plants to H2S pollutant significantly reduced the head yield, more at 100 ppm (-50%) than that at 50 ppm (-33%). The values of chemical components, i.e., vitamin C, total protein, total soluble sugars (SS), total amino acids and N, P, K minerals contents in head lettuce leaves significantly decreased with increasing the H2S level. While the Sulphur (S) contents, soluble phenols, NO3-N and NO2-N in lettuce leaves were increased as H2S rates increased. Adding ascorbic acid to the H2S-polluted lettuce plants not only led to overcome the deleterious effect of intolerable H2S levels (50 and 100 ppm) on most above-mentioned characters, but also increased the yield (150 and 169%) and improved the qualitative characters of head lettuce leaves.