Hakan Kibar

This study was carried out to determine the effects of exogenous putrescine, salicylic acid, citric acid, and methyl jasmonate treatments at different doses (0.5 mM, 1.0 mM, and 2.0 mM) after harvest on quality properties, storage period, and nutrient content in Pleurotus ostreatus mushroom species, which ranks second in terms of production in the world and deteriorates rapidly after harvest and loses its quality. A total of 13 different treatments were examined in the study, and the necessary measurements and analyses (on the 7th and 14th days) were performed on the mushrooms stored at 4°C for 14 days. As a result of the research, it was determined that the postharvest quality characteristics changed significantly depending on treatments and storage periods. The results showed that postharvest treatments significantly influenced weight loss, dry matter, protein content, color, pH, and mineral composition during storage. Compared to the control, 0.5 mM methyl jasmonate was the most effective in preserving protein content (increased by 13.56%) and calcium content (increased by approximately threefold), while 2.0 mM citric acid reduced weight loss by 7.76% and increased zinc content by 57%. Principal component analysis and cluster analysis further confirmed that citric acid and methyl jasmonate treatments were superior in maintaining postharvest quality. It was concluded that 0.5 mM methyl jasmonate, 0.5 mM, 1.0 mM, and 2.0 mM citric acid treatments can be recommended as an alternative application method to reduce postharvest quality losses of P. ostreatus.

This study evaluates the effects of ultraviolet (UV) radiation (UVA, UVB, and UVC) on the postharvest quality and nutritional stability of fresh-cut spinach during cold storage. Spinach samples were exposed to UV treatments for 0, 5, or 10 min and stored at 4 ± 1 °C with 85 ± 5% relative humidity for up to 10 days. Weight loss, dry matter content, total soluble solids, electrical conductivity, pH, respiration rate, color parameters, ash content, and mineral composition were assessed. The results showed that UVB-treated spinach had the lowest weight loss (0.52%), compared to UVC-treated (0.75%) and control (0.82%) samples. The dry matter content was highest in UVB-treated samples (9.56%) and lowest in UVC-treated samples (8.62%). UVC exposure increased electrical conductivity (112 µS cm⁻¹), indicating greater ion leakage. UVA and UVB treatments preserved the chlorophyll content (SPAD values of 34.5 and 37.0, respectively) and reduced the respiration rates. These physiological responses are indicative of delayed senescence and improved storage potential. UVB-treated samples retained higher potassium (4040 mg 100 g⁻¹), calcium (1445 mg 100 g⁻¹), and phosphorus (375 mg 100 g⁻¹), while UVC-treated samples showed greater mineral loss. Hierarchical clustering analysis revealed distinct metabolic responses among UV treatments. This study provides a novel comparative assessment of UVA, UVB, and UVC effects on fresh-cut spinach, demonstrating UVB as the most effective non-chemical method for enhancing shelf life while preserving nutritional quality.

Salinity is one of the most important abiotic stresses limiting the productivity of agricultural production. Putrescine and salicylic acid are recognized for their pivotal roles in facilitating physiological and metabolic processes in plants, while also enhancing the plant’s resilience to various abiotic stressors. The present study investigated the effects of exogenous putrescine and salicylic acid treatments on germination, growth and biochemical properties of cowpea under salt stress. Putrescine and salicylic acid treatments significantly alleviated the negative effects of salt stress by improving the germination and growth under salinity. 1.0 mM Putrescine + 100 mM Sodium chloride treatment increased germination by 48.59% and plumule length by 19.44% and 0.5 mM Putrescine + 100 mM Sodium chloride treatment increased the seedling fresh weight by 29.85%, seedling height by 13.81% and chlorophyll by 19.47% compared to the 100 mM Sodium chloride treatment. Accordingly, 0.5 and 1.0 mM Putrescine under 100 mM Sodium chloride salt stress were found as the most effective treatments against salt stress. In conclusion, based on the beneficial effects of putrescine and salicylic acid on cowpea under salt stress, it can be said that these treatments are promising in reducing the negative effects of saltiness in cultivation in saline soils.

Salinity is a significant and detrimental factor that limits the growth and development of plants. Although the individual responses of putrescine (Put) and salicylic acid (SA) are well reported depending on various abiotic stresses, their combined response under salinity stress remains largely unexplored. This study aimed to assess the impact of exogenous Put and SA on the germination, seedling growth, and biochemical properties of peas subjected to salinity stress. The research involved 15 different treatments with two dos of salt (100 and 200 mM), two Put concentrations (0.5 and 1 mM), and two SA concentrations (0.5 and 1 mM), evaluating the individual and combined effects of salt, Put, and SA. The results suggested that the germination, seedling development, and biochemical properties of peas were significantly responsed by salt stress, as well as by Put and SA applications. Salinity markedly decreased both germination and seedling growth. However, the use of Put and SA greatly mitigated the negative effects of salt stress, promoting the germination and seedling development of peas in salty conditions. Furthermore, the simultaneous application of 0.5 mM SA and 100 mM NaCl led to a 22.73% increase in germination rate, a 44.72% increase in seedling fresh weight, and a 21.84% increase in chlorophyll content, compared to the sole application of 100 mM NaCl. The research indicates that the exogenous treatment of Put and SA can mitigate the detrimental effects of salinity, thereby enhancing seedling development and germination in peas.

Salinity poses a significant abiotic stress that limits plant productivity, thereby posing a serious threat to agricultural sustainability and worldwide food security. Techniques that can overcome this problem are needed. Recent focus has been placed on employing organic substances like humic acid (HA) and amino acids, including L‐tryptophan (L‐TRP), to mitigate the negative effects of salt stress on cultivated plants. Accordingly, in this research, the impact of foliar applications of HA and L‐TRP, both separately and combined, on the growth parameters and biochemical properties of spinach subjected to salt stress was investigated. In the present study, eight treatments (1. control, 2. salt (NaCl), 3. HA, 4. L‐TRP, 5. HA + NaCl, 6. L‐TRP + NaCl, 7. HA + L‐TRP, and 8. HA + L‐TRP + NaCl) were investigated. The study showed that salt stress markedly reduced several growth properties in spinach, including plant height, number of leaves, leaf dimensions, and both fresh and dry weight. Additionally, it significantly lowered contents of chlorophyll (a, b, and total), carotenoid, polyphenol, lutein, anthocyanin, polyphenol oxidase, glycine betaine, relative water content, and the antioxidant enzyme activities (ascorbate peroxidase, catalase, peroxidase, and superoxide dismutase). On the other hand, significant increases were observed in sodium, chlorine, potassium, sulfur, zinc, nickel, proline, malondialdehyde, and hydrogen peroxide levels of spinach with salinity. Individual and combined applications of HA and L‐TRP positively influenced plant growth, relative water content, activities of antioxidant enzyme, chlorophyll, and mineral contents of spinach under both normal and saline conditions. In conclusion, the combined use of HA and L‐TRP under salt stress conditions is promising in mitigating the negative impacts of salinity and can be suggested as an effective alternative approach for cultivating spinach in saline environments.

Cauliflower is among the perishable vegetables after harvest. In recent years, the popularity of fresh-cut cauliflower has increased among consumers as a minimally processed product. This study was carried out to determine the effects of exogenous putrescine (PUT), citric acid (CA) and salicylic acid (SA) treatments on postharvest quality of fresh-cut cauliflower stored at 4±0.5 °C and 90±5% relative humidity for 21 days. In the study, a total of seven different treatments using two different doses (0.5 and 1.0 mM) of PUT, CA and SA were investigated. To evaluate the quality of fresh-cut cauliflower, the necessary measurements and analyzes were performed at periodic intervals on days 0, 7, 14, and 21 of storage. The results demonstrated that quality properties changed significantly depending on the postharvest treatments and storage durations. With the increase of storage duration, weight loss and ash content increased, while K, Zn and Cu contents decreased. In general, the treatments examined in the study had positive effects on postharvest quality of cauliflower. Among the treatments, especially 1.0 mM PUT was found to be more effective. Compared to the control, 1.0 mM PUT treatment decreased weight loss by 61.32%, though it increased protein content by 14.48% and P content by 21.55%. It was concluded that 1.0 mM PUT treatment can be recommended as an alternative application method to extend the storage life of fresh-cut cauliflower and reduce postharvest quality losses.