Foliar Application of Nano, Chelated, and Conventional Iron Forms Enhanced Growth, Nutritional Status, Fruiting Aspects, and Fruit Quality of Washington Navel Orange Trees (Citrus sinensis L. Osbeck)

Iron (Fe) is required for most metabolic processes, including DNA synthesis, respiration, photosynthesis, and chlorophyll biosynthesis; however, Fe deficiency is common in arid regions, necessitating additional research to determine the most efficient form of absorbance. Nano-fertilizers have characteristics that are not found in their traditional equivalents. This research was implemented on Washington navel orange trees (Citrus sinensis L. Osbeck) to investigate the effect of three iron forms—nano (Fe-NPs), sulfate (FeSO4), and chelated (Fe-chelated)—as a foliar spray on the growth, fruiting aspects, and nutritional status of these trees compared to control. The highest values of the tested parameters were reported when the highest Fe-NPs level and the highest Fe-chelated (EDTA) rate were used. Results obtained here showed that the spraying of the Washington navel orange trees grown under similar environmental conditions and horticulture practices adopted in the current experiment with Fe-NPs (nanoform) and/or Fe-chelated (EDTA) at 0.1% is a beneficial application for enhancing vegetative growth, flower set, tree nutritional status, and fruit production and quality. Application of Fe-NPs and Fe-chelated (EDTA, 0.1%) increased yield by 32.0% and 25% and total soluble solids (TSS) by 18.5% and 17.0%, respectively, compared with control. Spraying Washington navel orange trees with nano and chelated iron could be considered a significant way to improve vegetative growth, fruit production, quality, and nutritional status while also being environmentally preferred in the arid regions.

Evaluation of the Structural, Physicochemical and Functional Properties of Dietary Fiber Extracted from Newhall Navel Orange By-Products

Ultrasound-assisted enzymatic treatment was used to treat Newhall navel orange peel and residue, and then the structural, physicochemical and functional properties of extracted soluble dietary fibers (SDF) and insoluble dietary fibers (IDF) were investigated. The structural properties were determined using scanning electron microscopy, X-ray diffraction, FT-IR and monosaccharide composition. Among these dietary fibers, residue-SDF showed a more complex structure, while peel-IDF exhibited a looser structure. Four samples showed representative infrared spectral features of polysaccharides, typical cellulose crystalline structure and diverse monosaccharide composition. Furthermore, residue-IDF exhibited higher oil-holding capacity (2.08 g/g), water-holding capacity (13.43 g/g) and nitrite ion adsorption capacity (NIAC) than other three samples, and residue-SDF showed the highest swelling capacity (23.33 mL/g), cation exchange capacity (0.89 mmol/g) and cholesterol adsorption capacity (CAC) among these dietary fibers. In summary, this study suggests that the residue-SDF and residue-IDF could be used as the ideal dietary fibers for application in the functional food industry.

The Effect of Foliar Spraying With Some Growth Stimulants on Improving Vegetative Growth and Mineral Content of Seedlings of Navel Orange and Blood Orange

This study was carried out in lath house of the Department of Horticulture and Landscape Engineering - College of Agriculture - Tikrit University, during the season 2020-2021, as a factorial experiment by spraying with three levels of the growth regulator Brassinolide (BL) which are 0.00, 0.015, 0.025 Mg.L−1 and spraying with nutrient solution PRO-SOL (M) at three concentrations of.000, 200,400. Mg.L−1 to determine the effect of the growth regulator Brassinolide and the nutrient solution PRO-SOL in increasing the chemical content of some nutrients for the two types of navel orange V1 and blood orange V2. The results showed that blood orange V2 was significantly superior to the cultivar Navel V1 in the leaf area amounted to 2991 cm2, the percentage of dry matter in the leaves was 35.39% and the percentage of mineral elements in the leaves was %N, 1.619 %K, 1.37%P, 0.204,. And the best concentration Of Brassinolide 0.025 Mg.L−1 with a concentration of PRO-SOL400 Mg.L−1 has increased the dry matter percentage, leaf area and chemical content of elements for the navel orange variety V1, and the concentration of Brassinolide 0.015 Mg.L−1 with a concentration of PRO-SOL 400 mg.L-1 has increased the dry matter percentage, leaf area and chemical content of elements for blood orange variety V2.