Tropical fruits are in high demand for their flavor and for their functional composition because these compounds are considered nutraceuticals. Passion fruit production is of economic importance to Ecuador; however, several Passiflora species are grown and each has to be analyzed to identify their phytochemical composition. In this study, the polyphenol, flavonoid, carotenoid, vitamin C, sugar and organic acid contents were determined. Six different Passiflora spp. germplasms were analyzed, coming from Passiflora edulis f. flavicarpa, Passiflora alata, Passiflora edulis f. edulis and unidentified Passiflora species (local germplasm). Measurement techniques included reflectometry for vitamin C, spectrophotometry for antioxidant compounds and HPLC for sugars and organic acids. Data were analyzed by principal component analysis, correlation and analysis of variance. Results showed that INIAP 2009 and P10 showed a high amount of polyphenols, antioxidant activity and citric content. Sweet passion fruit had the lowest vitamin C content while Gulupa showed the highest content. In terms of the local germplasm, POR1 showed the lowest content of flavonoids while PICH1 had high flavonoid and carotenoid content. Polyphenols were the main compounds that influenced antioxidant activity. This phytochemical information adds value to passion fruit as a nutraceutical source.

Pre-sowing seed priming is one of the methods used to improve the performance of tomato plants under salt stress, but its effect photosynthesis, yield, and quality have not yet been well investigated. This experiment aimed to alleviate the impact of sodium chloride stress on the photosynthesis parameters of tomato cv. Micro−Tom (a dwarf Solanum lycopersicum L.) plants exposed to salt stress conditions. Each treatment combination consisted of five different sodium chloride concentrations (0 mM, 50 mM, 100 mM, 150 mM, and 200 mM) and four priming treatments (0 MPa, −0.4 MPa, −0.8 MPa, and −1.2 MPa), with five replications. Microtome seeds were subjected to polyethylene glycol (PEG6000) treatments for 48 hours for priming, followed by germination on a moist filter paper, and then transferred to the germination bed after 24 h. Subsequently, the seedlings were transplanted into the Rockwool, and the salinity treatments were administered after a month. In our study salinity significantly affected tomato plants’ physiological and antioxidant attributes. Primed seeds produced plants that exhibited relatively better photosynthetic activity than those grown from unprimed seeds. Our findings indicated that priming doses of −0.8 MPa and −1.2 MPa were the most effective at stimulating tomato plant photosynthesis, and biochemical contents under salinity-related conditions. Moreover, primed plants demonstrated relatively superior fruit quality features such as fruit color, fruit Brix, sugars (glucose, fructose, and sucrose), organic acids, and vitamin C contents under salt stress, compared to non-primed plants. Furthermore, priming treatments significantly decreased the malondialdehyde, proline, and hydrogen peroxide content in plant leaves. Our results suggest that seed priming may be a long-term method for improving crop productivity and quality in challenging environments by enhancing the growth, physiological responses, and fruit quality attributes of Micro-Tom tomato plants under salt stress conditions.

Tomato cultivation grapples with salt stress, disrupting growth parameters and physiological processes. High salinity levels induce osmotic stress, impacting cellular integrity and hindering metabolic activities. Salt accumulation at the root zone alters key physiological attributes, compromising overall harvestable output. Seed priming emerges as a potential solution to enhance plant resilience. A research gap exists in understanding the combined influence of polyethylene glycol and sodium chloride as seed priming agents under salt stress conditions. The study occurred in the Greenhouse of Laboratory Horticultural Science at Tokyo University of Agriculture. Micro Tom seeds underwent a factorial randomized design, involving five salinity and four priming treatments. Replicated ten times, totaling 200 plants, seed priming used polyethylene glycol, inducing salinity stress with sodium chloride. Meticulous measurements of growth parameters, photosynthetic traits, yield attributes, and electrolyte leakage were conducted. Statistical analyses discerned treatment effects at a 5% significance level. Seed priming, especially with ‘PEG plus NaCl’, effectively mitigated salt stress effects on tomato plants. Under severe salt stress, primed plants exhibited increased plant height, trusses, leaves, and leaf area. Photosynthetic efficiency and yield attributes demonstrated significant improvements with seed priming. Electrolyte leakage, indicative of leaf damage, was notably reduced by seed priming treatments, with ‘PEG plus NaCl’ exhibiting the highest efficacy. These results offer valuable guidance for optimizing agricultural practices in saline environments, contributing to sustainable strategies for food security amidst escalating environmental challenges.

There are several species of passion fruit grown in South America. However, there is a lack of information about the mineral content in their pulp. Thus, the objective of the present research was to determine the mineral content in the pulp of different germplasms of passion fruit [Passiflora edulis f. flavicarpa (INIAP 2009 and P10), P. alata (Sweet passion fruit), P. edulis f. edulis (Gulupa) and Passiflora sp. (Criollo POR1 and Criollo PICH1)] grown in Ecuador and to determine their relationship with relevant fruit quality traits. The results showed that high Mg content was associated with less peel thickness, soluble solids was negatively related to K and B content, and vitamin C was negatively related to S content. INIAP 2009 had high titratable acidity and fruit weight but low N and Na; P10 showed the highest contents of N, K, Na, Mn and fruit weight but less P, Mg, and Fe; sweet passion fruit showed high S, Zn, Cu, soluble solids, and peel thickness but low K, Ca, B, and titratable acidity; Gulupa had high Mg, B, and Zn but low S, Fe, and Mn; Criollo POR1 showed high N and Fe but low Zn; and Criollo PICH1 showed high P, Ca, Mg, and Cu but low soluble solids and peel thickness. These results provide additional information on passion fruit germplasm grown in Ecuador and constitutes a reference for further breeding programs.

Salt stress is a major constraint to crop productivity, negatively affecting plant physiology and fruit quality. This study hypothesized that seed priming with polyethylene glycol (PEG6000) might enhance antioxidant activity by mitigating oxidative stress in Solanum lycopersicum ‘Micro-Tom’ under salt stress. Seeds primed with –1.2 MPa PEG6000 were grown in Rockwool and treated with 0, 50, 100, 150, and 200 mM NaCl. Primed plants showed a 32% increase in leaf potassium (K⁺) and a 28% decrease in sodium (Na⁺) accumulation compared to non-primed plants under 150 mM NaCl. Glucose, fructose, and sucrose contents increased by 25%, 22%, and 19%, respectively, in primed fruits, while citric acid decreased by 15%. Malondialdehyde (MDA) and electrolyte leakage were reduced by 35% and 29%, respectively, in primed plants under moderate salinity. Antioxidant enzyme activities—SOD, POD, CAT, and APX were enhanced by 30–45% in primed plants under 100 and 150 mM NaCl, compared to non-primed controls. Abscisic acid (ABA) levels increased by 40% in primed roots under salt stress. Activities of polyamine-related enzymes (DAO, PAO, and ADC) also rose significantly. Priming improved protein content by 20% and relative water content by 18%. These results suggest that PEG6000 seed priming enhances salt tolerance by boosting antioxidant defense, regulating osmotic balance, and improving ion homeostasis, offering a viable strategy for sustaining tomato productivity under salinity.