Peach is a climacteric fruit characterized by a rapid maturation, high respiration level, weight loss, breakdown of texture, and interior browning. Fast tempering of the fruit and subsequent mold expansion caused a negative impact on the marketing. This study was carried out to estimate the synergistic influence of coating with Aloe vera gel (AVG) at 15% or 30% mixed with chitosan (CH) at 1.5% as a kind of natural polymers or calcium chloride (CaCl₂) at 3% on physical and chemical features. We investigated the changes in antioxidant enzymes activities of peach fruits Prunus persica (L.) Metghamer Sultany. Fruits were kept at 3 ± 1 °C and relative humidity (RH) 85–90% for 36 days during two consecutive seasons (2020 and 2021). Results revealed that applying AVG at 30% blended with CH at 1.5% significantly impacted the storage period of peach fruits, reduced the ion leakage (IL), malondialdehyde (MDA), and lessened weight loss. The differences were significant compared to the other treatments and untreated fruits (control) that exhibited the higher values for IL, MDA, and weight loss in the 36th day. Moreover, fruit quality features such as firmness, total acidity (TA), total soluble solids (TSS), and skin color chroma (c*), hue angle (h) were also maintained. Furthermore, this combination was raised of phenolic content, antioxidant capacity (DPPH), antioxidant enzyme activity such as catalase (CAT), peroxidase (POD), and quench the generation of H₂O₂ and O₂•−. It could be concluded that dipping peach fruits in AVG at 30% blended with CH at 1.5% retained the biological features of peach fruit at considerable levels during cold storing. Thus, this effective mixture can be utilized to prolong the storage and marketing period of peach fruits. Nevertheless, a more in-depth analysis is required for this edible coating to be successfully commercialized in the peach fruit post-harvest industry.

A field trial study was conducted for two consecutive seasons 2020 and 2021 in approximately 8-month-old jojoba plants to evaluate the physiological responses following salt treatment and the role of proline as a foliar application to enhance jojoba tolerance to salinity stress. Jojoba plants were irrigated once a week for four months with diluted seawater in concentrations of 5000, 10,000, and 15,000 ppm and tap water (control). Anti-stress proline was applied four times throughout the experiment, the first at the beginning of the experiment and another three times at 30-day intervals, at concentrations of 0, 300, and 450 ppm. The effect of proline treatments on jojoba plant behavior includes growth vegetative characteristics, namely plant height increase percentage (PHIP), shoot number increase percentage (NSIP), stem diameter increase percentage (SDIP), number of leaves, leaf thickness, leaf area, and fresh and dry weights of leaves, and chemical characteristics, namely chlorophyll a and b, total chlorophyll, carotenoids, leaf mineral contents (N, P, K, Na, and Cl), total phenolic content (TPC), and proline concentration. Moreover, the impacts of proline on hydrogen peroxide (H₂O₂), superoxide anion (O₂^•−), malondialdehyde (MDA), and ion leakage (IL) under salinity stress were investigated. Briefly, proline at 450 ppm enhanced all studied growth and physiological characteristics and promoted the antioxidant system of jojoba plants compared with the control and other treatments. The anatomical structure of leaves was also examined, and favorable variations in the anatomical structure were detected in the stressed and proline-treated plants. Exogenous application of proline enhanced most of this anatomical characteristic of jojoba leaf under saline stress. In conclusion, proline as a foliar application at 450 ppm under salinity stress of 10,000 ppm enhances jojoba tolerance to salinity stress by modifying the physicochemical and morphological characteristics of jojoba plants.

Effectiveness of edible coatings such as Jojoba oil (JO) at 5%, Arabic gum (AG) at 10% and Paraffin oil (PA) at 7.5% as solely or in combination on physical and chemical characteristics of Zaghloul date palm fruits stored at 0±1C° and R.H. 85-90 % for 6 weeks were investigated during two successive seasons (2018 and 2019). The achieved data registered that all tested treatments prolonged the cold storage period of Zaghloul date palm fruits as compared to the control (Tap water). Fruits treated with JO at 5% combined with AG at 10% significantly recorded the highest responses, where it significantly mitigated the rise in decay incidence and reduced weight loss, and maintained high firmness, total phenol content, total flavonoids, total tannins, total sugars and antioxidant activity. Also, the result of ion leakage detected that this treatment protected the cell membrane integrity. According to these results, Jojoba oil (JO) at 5% combined with Arabic gum (AG) at 10% application could be suggested to maintain the storability during cold storage of Zaghloul date palm fruits.

The variety of navel orange known as “Cara Cara” trees are greatly affected by soil salinity, which adversely influences yield and quality. Therefore, adopting the use of safe and inexpensive materials is crucial in this case. Herein, bio-stimulants (whey protein hydrolysates, and humic acid), and ascorbic acid could be utilized to promote plant growth in both normal and salt-stress environments. Two field trials were implemented to investigate the response of navel orange trees to whey proteins hydrolyzed (WPH) with pepsin (PEH at a concentration of 1000 mg L ⁻¹ ) and papain (PAH at a concentration of 1000 mg L ⁻¹ ), or ascorbic acid (ASA) at a concentration of 1000 mg L ⁻¹ , and/or humic acid (HA) (applied to the soil at a concentration of 1000 mg L ⁻¹ ). The changes in fruit yield, fruit quality, physio-biochemical attributes, and antioxidant defense systems under salinity stress (with an electrical conductivity of 5.14 dS m ⁻¹ ) were estimated. All treatments involving HA with WPH or ASA significantly improved various fruit yield and quality traits, physiological and photosynthetic performance attributes as well as enzymatic and non-enzymatic antioxidants, comparing to the check treatment in both seasons. In this context, PEH + HA treatment was the efficient practice for increasing fruit yield per tree by 80.3 and 82.7%, total acidity by 162.3 and 250.0%, vitamin C by 10.7 and 13.6%, total soluble solids by 12.5 and 8.3%, net photosynthetic rate by 82.3 and 80.9%, relative water content by 27.9 and 28.0%, and membrane stability index by 44.2 and 43.0%, while decreasing electrolyte leakage by 56.0 and 57.0%, and malondialdehyde by 57.8 and 58.3% during two seasons, respectively, as compared to check treatment. Also, PEH + HA treatment showed the highest potentiality for ameliorating the defensive mechanism indices elevating catalase by 17.3 and 17.2%, super oxide dismutase by 122.2 and 122.1%, and glutathione by 97.9 and 99.0%, while suppressing hydrogen peroxide by 45.7 and 45.6% and superoxide radical by 47.9 and 49.3%, during the two seasons, respectively, as compared to the check treatment. Furthermore, it should be mentioned that the values of most fruit yield and quality traits, photosynthetic efficiency, physiological performance and ant-oxidative indices obtained with application of PAH + HA and ASA + HA treatments were as similar as those of gained by PEH + HA. Therefore, the outcomes of the current study indicated that using integrated PEH + HA, PAH + HA and ASA + HA treatments are considered helpful practices for growing citrus plants and maintaining yield and quality in saline soil circumstances.

Cold storage is used to improve the efficiency of storage and handling of orange fruits, but the fruits are exposed to chilling injury (CI). Antioxidant enzymes are part of the antioxidant defence system against CI of ‘Washington’ oranges during cold storage, which controls storage/handling efficiency. In this study, melatonin (ME) was used on fruits to reduce cold damage. To assess the action of ME influences; fruits were picked from the tree at the commercial maturity stage and divided into two groups that were uniform in size and colour. Then, they were immersed in ME solution at 0 mmol, 10 mmol, 100 mmol or 1,000 mmol for 20 min at 20 ± 1 °C. The treated fruits were stored at 4 ± 1 °C and 95 ± 1% RH for 4 weeks during 2019 and 2020 seasons. The physical and chemical characteristics of the stored fruits were measured every week up to the end of the storage period. Results indicated that immersing fruits in 1,000 μM ME minimised the CI-index and the water loss%, while preserving the orange peel colour (h°) during cold storage. On the other hand, the same treatment caused slight changes in soluble solid content (SSC%), maintained ascorbic acid (AA) content and the stability of total acidity (TA%), enhanced the antioxidant enzymes activities (AEAs) such as ascorbate peroxidase (APX), catalase (CAT), and superoxidase dismutase (SOD) and also reduced the rate of malondialdehyde (MDA) and ion leakage (IL) during cold storage. Moreover, it minimised hydrogen peroxide (H ₂ O ₂ ) and superoxide anion (O ₂ ^•− ) production and caused pronounced results to be exhibited in antioxidant capacity. Overall, the 1,000 μM ME treatment for orange fruits afforded more tolerance against cold storage stress.