Salt stress results in physiological changes that inhibit plant growth and development. Ca-complex sources are used as a potential salt stress attenuator. This study was carried out with the aim of verifying the effects of Ca-complex sources in reducing the effects of saline water stress on the physiological aspects of sour passion fruit seedlings. The experiment was carried out in a randomized block design with a 2 × 2 × 3 factorial scheme, consisting of two cultivars of sour passion fruit (BRS GA1 and BRS SC1), two levels of water salinity (electrical conductivity of 0.5 and 4.0 dS m⁻¹) and three sources of Ca-complex (without, organic acids and amino acids). The traits measured at 60 days after sowing were gas exchange, chlorophyll indices, chlorophyll fluorescence, electrolyte leakage, and relative water content in the leaf limb. Under moderate water salinity, the application of Ca-complex in amino acids promoted increases of 49.84% and 43.71%, respectively, in the efficiency of water use and carboxylation. The application of complex sources increased the stability of cell membranes, reducing electrolyte leakage, providing higher relative water content in seedlings irrigated with moderately saline water. From the results, we conclude that Ca-complex sources have potential as modulators of moderately saline water stress in sour passion fruit seedlings.

Salinity is an abiotic factor that impairs the growth and physiological, biochemical, and molecular mechanisms of plants. Among plants, soybeans are an important crop worldwide, so managing abiotic factors is essential to mitigate plant damage. However, biostimulants, such as melatonin, are being employed to alleviate the stress caused by these factors. Therefore, this study aimed to evaluate the growth, photosynthetic pigments, and water relations of soybean plants subjected to salinity levels and exogenous melatonin application. The research was conducted in experimental area belonging to the Federal Rural University of the Semi-Arid Region, Mossoró, RN, Brazil. The experimental design was randomized blocks, arranged in a 3 x 3 factorial scheme (three salinity levels in the irrigation water - 0.50, 3.00, and 5.00 dS m^-1 and three melatonin concentrations - 0, 0.5, and 1 mM) with three replications. At 47 days after planting, plant height, stem diameter, number of leaves, root length, chlorophyll content (a, b, and total), relative water content, leaf moisture, and electrolyte leakage were evaluated. Soybean plants tolerated the effects of salinity on growth aspects, photosynthetic pigments, and water relations up to 3.00 dS m^-1, regardless of melatonin concentration. Exogenous application of melatonin mitigated the effects of salt stress on chlorophyll b and relative water content at salinity level of 5.00 dS m^-1 and concentration of 1 mM.

As a fresh food, sweet potatoes are highlighted for their taste and appearance. In the industry, they are valued for their starch and sugar content. In both scenarios, much attention has been given to the composition of bioactive compounds. The application of abiotic stresses seems to induce an overproduction of these compounds in some vegetables. The objective was to examine the influence of harvest time on the synthesis and accumulation of bioactive compounds in varieties of minimally processed sweet potatoes with different flesh colors. Sweet potato cultivars (Beterraba, Jerimum, Mãe de Família Roxa, and BRS Cuia) were harvested at 120, 150, and 180 days after planting, then subjected to minimal processing and stored at 5 ºC for 10 days. The most recommended time for harvesting sweet potatoes in semi-arid conditions for minimal processing by the industry is between 150 and 180 days. This is the period when the sweet potatoes exhibit the best quality for fresh consumption, as detected in ‘Mãe de Família Roxa’ and ‘Jerimum’. ‘BRS Cuia’ harvested at 120 days showed the highest phenolic compound levels, the highest polyphenol oxidase and peroxidase enzyme activities, and the most intense browning symptoms. In addition to its starch content, it can be used as a raw material for the extraction of phenolic compounds of interest. ‘Beterraba’ showed low sugar values, rendering them unfavorable for fresh consumption or minimal processing. However, this cultivar also exhibited a high content of carotenoids, making them bio-factories for the food and pharmaceutical industries.

Salinity stress is one of the main limitations to the expansion of sour passion fruit areas in the semi-arid region of Brazil. Studies have shown that the application of calcium reduces the deleterious effects of salinity, especially when sources of rapid availability and absorption are used. The objective of this study was to evaluate the effect of complexed calcium sources on the growth and quality of sour passion fruit seedlings under salt stress. The experiment was conducted in a randomized block design, in a 2 × 2 × 3 factorial arrangement, relating to two sour passion fruit cultivars (BRS GA1 and BRS SC1), two levels of water salinity (0.5 and 4.0 dS m-1), and sources of complexed calcium (without calcium, complexed in organic acids, and complexed in amino acids). The following parameters were evaluated: height, stem diameter, root length, leaf area, dry mass (aerial part, root, and total), and Dickson's quality index. The results indicate that irrigation water with a salinity of 4.0 dS m-1 negatively affects the growth and quality of sour passion fruit seedlings, reducing plant height by 72.44% in BRS GA1 and 58.76% in BRS SC1 in the treatment without calcium. Under saline conditions, calcium complexed in organic acids showed more consistent mitigating effects, increasing total dry mass by 43.77% compared to the treatment without calcium. The use of calcium complexed with organic acids represents a promising strategy to mitigate salt stress during the seedling stage of sour passion fruit.

Pitaya is a high-value tropical fruit with a postharvest life constrained by rapid physiological deterioration. This study aimed to evaluate the efficacy of chitosan-based (CH) biopolymeric coatings, enriched with ascorbic acid (AA), on the postharvest quality and preservation of pitaya fruits stored under refrigeration (12 °C). The fruits were subjected to different treatments and evaluated for biometric and physicochemical parameters, including weight loss, total soluble solids, pH, titratable acidity, and the SS/TA ratio throughout storage. The results demonstrated that the coatings significantly reduced weight loss (e.g., 4.15% for the CH4AA treatment) and contributed to the maintenance of quality attributes, delaying senescence-associated processes. Among the treatments, the combination of chitosan with ascorbic acid was the most effective in preserving fruit quality, extending the marketable shelf life from 10 to 20 days. These findings indicate that the use of biopolymeric coatings is a promising strategy to prolong the shelf life and maintain the postharvest quality of pitaya, with potential applications in commercial supply chains.