The application of the free radical nitric oxide (NO) donors (arginine and sodium nitroprusside) have protective effects on plants in alleviating salinity stress throughout improving the enzymatic activities of antioxidant enzymes and osmotic adjustment which induced plant antioxidative defense system. This experiment carried out to study the effect of soaking seeds of sunflower plant in different concentrations of arginine or sodium nitroprusside (SNP) on growth, some physiological parameters, yield and chemical composition of the yielded seeds of sunflower under salinity stress. Growth parameters (shoot length, stem diameter, no. of leaves, shoot fresh, and dry weights) decreased significantly with salinity stress and such effect ameliorated using the two levels of both arginine and SNP. Photosynthetic pigments significantly increased in the arginine and SNP treated plants under salinity stress or not stressed ones. Phenol and indole acetic acid as well as compatible solutes as total soluble sugar and proline showed highly significant increase with arginine and SNP treatments either in unstressed plants or those under salinity stress conditions. Free amino acids showed significant increase in both unstressed and stressed sunflower plants treated with either arginine or SNP. High level of arginine recorded the highest values of TSS, proline, free AA, phenol, and IAA in both unstressed and salinity stressed plants. Arginine and SNP with salinity levels showed a highly significant increase in various antioxidant enzymes compared to the control plants. Arginine or SNP at all tested concentrations decreased significantly plant content of Na, while K and P highly significantly increased and Ca, Mg, and N non-significantly increased. The yield parameters showed in general highly significant increase in head diameter, 100-seed weight, seed yield/plant, and oil% with arginine or SNP with the superiority of the higher concentration of both treatment materials. Both arginine and SNP increased markedly total unsaturated (TU) fatty acids as well as TU/TS with superiority of high concentration of SNP treatment in that domain. Soaking seeds of sunflower plant with arginine and SNP improved yield parameters of sunflower. High level of SNP under salinity stress conditions proved to be the most effective.

Numerous plant metabolites, especially amino acids, are accumulated as a result of stress. These amino acids are crucial for plant metabolism and development and have historically been viewed as the building blocks of proteins. Several studies suggested that there is a link between proline buildup and exposure plants to stress. Proline performs important functions under stress in addition to be a great osmolyte, antioxidant enzyme, acts as an antioxidant defense and signaling molecules. Two field trials were during two successive winter seasons (2020/2021 and 2021/2022). The effects of proline foliar application (0, 100, 200, 300 and 400 mg L−1) and irrigation water levels (irrigation by 100, 80 and 60% of crop water requirements, CWR, CWR100, CWR80 and CWR60, respectively) on plant pigments, antioxidants activity, yield traits and nutrient contents of wheat were assessed. The experiment was designed in a split-plot involving 4 replicates. Drought stress (CWR80 and CWR60) led to reductions in photosynthetic pigments, and yield components. Under severe water stress (CWR60), proline 200 and 300 mg L−1 recorded the highest values of chlorophyll a, chlorophyll b, and total pigments. Application of proline 300 mg L−1 was the potent practice for enhancing the antioxidant activity% (DPPH radical scavenging) and phenols content under CWR100 and CWR80. Indole acetic acid (IAA) possessed the maximum values with proline 200 mg L−1 under all irrigation patterns. Under severe deficit water (CWR60), without proline spraying (for super oxide dismutase), 200, 300 or 400 mg L−1 proline (for peroxidase) and 200 or 400 mg L−1 proline (for polyphenol oxidase) recorded the highest values. Spraying proline 300 mg L−1 achieved the highest values of grain number spike−1, weight of 1000 grains and grain yield ha−1 under different irrigation regimes. In conclusion, proline is considered a good mitigator for drought stress, due to it increased wheat plant tolerance to water deficiency throughout improving plant physiology and consequently yields quantity and quality. The most efficient concentrations of proline for coping the adverse impact of drought were 200 and 300 mg L−1.

Background and objective: Researches on compost introduced the evidence of its benefits to plant productivity and soil fertility. These advantages are noticed in forms of improving soil water holding capacity and nutrient availability for plants. These changes can also improve plants’ capability to overcome salinity stress conditions. The application of osmo-protectant materials (proline and trehalose) and/or compost addition enhances plant antioxidative defense system against stress conditions. This experiment conducted to study the effect of spraying quinoa plants with proline and trehalose with and without soil compost addition under salinity stress on some morphological and physiological aspects. Materials and methods: Quinoa plant was grown with or without compost in the soil and foliar sprayed with proline or trehalose under salt irrigation. Plant samples were taken after 60 days from sowing and at the end of the experiment for growth, yield, and biochemical measurements. Results: Growth and yield measurements were decreased with salinity stress. High levels of both proline and trehalose recorded the highest values of total soluble sugars, proline, and free amino acids in both unstressed or salinity stressed plants with or without compost addition. The use of compost in soil for cultivating quinoa plants with either proline or trehalose treatments increased growth parameters, photosynthetic pigments, and yield attributes. In addition, these treatments improved the accumulation of some organic solutes in leaves and promoted antioxidant enzyme activities. Conclusion: Compost addition to soil with spraying proline or trehalose improved quinoa growth and yield and produced seed nutritional value.

Regulation of Antioxidant System in Wheat Cultivars by Using Chitosan or Salicylic Acid to Improve Growth and Yield under Salinity Stress

Growth, Yield and Biochemical Changes of Soybean Plant in Response to Iron and Magnesium Oxide Nanoparticles

Plant diseases are biotic stresses that restrict crop plants’ ability to develop and produce. Numerous foliar diseases, such as chocolate spots, can cause significant production losses in Vicia faba plants. Certain chemical inducers, including salicylic acid (SA), oxalic acid (OA), nicotinic acid (NA), and benzoic acid (BA), were used in this study to assess efficacy in controlling these diseases. A foliar spray of these phenolic acids was used to manage the impacts of the biotic stress resulting from disease incidence. All tested chemical inducers resulted in a significant decrease in disease severity. They also enhanced the defense system of treated plants through increasing antioxidant enzyme activity (Peroxidase, polyphenol oxidase, β-1, 3-glucanase, and chitinase) compared to the corresponding control. Healthy leaves of faba plants recorded the lowest (p < 0.05) values of all antioxidant activities compared to those plants infected by Botrytis fabae. Moreover, the separation of proteins using SDS-PAGE showed slight differences among treatments. Furthermore, foliar spray with natural organic acids reduced the adverse effects of fungal infection by expediting recovery. The SA (5 mM) treatment produced a pronounced increase in the upper, lower epidermis, palisade thickness, spongy tissues, midrib zone, length, and width of vascular bundle. The foliar application with other treatments resulted in a slight increase in the thickness of the examined layers, especially by benzoic acid. In general, all tested chemical inducers could alleviate the adverse effects of the biotic stress on faba bean plants infected by Botrytis fabae.