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Hydroponic-producing selenium (Se)-biofortified vegetables in a greenhouse is a convenient and effective way to provide Se-enriched food and overcome hidden hunger. CO2 fertilization is commonly implemented to increase vegetable yield in greenhouse production. However, this application accompanies decreased mineral concentrations in the edible parts. Here we investigated the effects of [CO2] and Se supply on the growth, gas exchange, and cucumber fruit quality. A hydroponic experiment with two CO2 concentrations ([CO2]) (C1: 410, and C2: 1200 μmol mol−1) and four Se supply levels (Se0: 0, Se1: 0.125, Se2: 0.250, and Se3: 0.500 mg Se L−1) was carried out. A low level of Se supply (Se1: 0.125 mg Se L−1) protected the photosynthetic pigments and stimulated the stomatal opening, especially under [CO2] fertilization. It leads to a higher net photosynthesis rate (Pn) and transpiration rate (Tr) than other Se treatments. The most significant changes in dry weight, fruit yield, and soluble sugar concentration were also obtained in Se1 under CO2 fertilization due to the enhanced CO2 fixation. Meanwhile, the Se concentration in fruit was 0.63 mg kg−1 FW in C2Se1, with the highest Se accumulation and use efficiency. According to the recommended dietary allowance of 55 μg Se day−1 for adults, an intake of 87 g of cucumber grown in C2Se1 is sufficient. Because of the improved Tr and better root structure in Se1, the uptake of mineral nutrients through mass flow and interception was well maintained under CO2 fertilization. So, the concentrations of N, P, K, Ca, and Mn in cucumber fruits were not significantly decreased by elevated [CO2] in Se1. However, the concentrations of soluble proteins, S, Mg, Fe, and Zn in cucumber fruits in C2Se1 were lower than those in C1Se1, which was mainly attributed to the dilution effects under CO2 fertilization. Therefore, a selenite supply of 0.125 mg Se L−1 was found to be the optimal dosage for producing Se-enriched cucumber fruits with high yield and better qualities under CO2 fertilization (1200 μmol mol−1). [ABSTRACT FROM AUTHOR]

Organic tomato cultivation is growing all over the world due to its healthy functional properties and environmental concerns. Recently, some new varieties with increased functional properties, particularly high lycopene, have been developed. However, few were assessed under organic farming systems. The objective of this study was to evaluate physico-chemical properties and the main bioactive compound contents, as well as lipophilic, hydrophilic and total radical scavenging activities of a recently developed high lycopene tomato variety homozygous for hp-2dg genes (HLT-F71) grown under organic conditions for two non-consecutive years (2019 and 2021) compared to the ordinary control 'Nemador' variety. The lycopene, β-carotene, total phenol, flavonoid, vitamin C, radical scavenging activity and tocopherols were analyzed by using spectrophotometric and HPLC methods, respectively. The high lycopene content variety presented suitable marketable yield, average fruit weight, pH, titratable acidity, firmness and higher °Brix, pulp color than the control. Additionally, it has significantly higher lycopene, β-carotene, total phenol, flavonoid, vitamin C and particularly considerable α-tocopherol contents, as well as radical scavenging activity. The high lycopene tomato variety with hp genes proved to be an effective sustainable variety for enhancing tomato fruit yield and functional properties even under organic grown conditions. [ABSTRACT FROM AUTHOR]

The effects of soilless substrate-based versus soil cultivation on overall fruit quality and yield in tomato (Solanum lycopersicum) were studied using the tomato cv. Zhonghua Lvbao. Experiments for tomato soilless cultivation were carried out under greenhouse conditions. Plant growth, fruit quality and yield, and physiologic traits were observed. RNA-seq and RT-PCR, as well as metabolomic analyses were performed to examine the expressed genes and metabolites under soilless substrate cultivation. The results showed that the plant height, stem diameter, and chlorophyll contents of tomato under substrate-based cultivation were increased by 37.3%, 19.8%, and 15.3%, respectively, compared with soil cultivation system. Leaf photosynthetic and transpiration rates, stomatal conductance, and root vitality of tomato, under substrate-based cultivation, increased by 29.0%, 21.2%, 43.9%, and 84.5%, respectively, compared with soil cultivation. The yield reached 7177.5 kg/667 m2, and the relative yield increased by 10.1%, compared with soil cultivation. The contents of total soluble sugar, soluble solids, and vitamin C increased by 35.7%, 19.7%, and 18.2%, respectively, higher than those of soil cultivation in tomato fruits, while nitrate content and titratable acid decreased by 29.4% and 11.8%, respectively. Therefore, substrate-based-cultivation can increase production and improve tomato fruit quality and taste. We examined the expressed genes and metabolites to explore the molecular mechanism of plant growth and overall fruit quality improvement in substrate-based cultivation. A total of 476 differentially expressed genes were identified by transcriptomes profiling, of which 321 and 155 were significantly up- and down-regulated, respectively. The results of metabolomics analysis showed that 441 metabolites were detected, where 24 and 36 metabolites were up- and down-regulated, respectively. By combining analyses of transcriptomic and metabolic groups, genes and metabolites related to the fruit quality were mainly concentrated in the vitamin B6/ascorbic acid/aldonic acidmetabolism, and glycerophospholipid metabolic pathways. Therefore, substrate-based cultivation can elevate vitamin and soluble sugar contents and the expression of fruit flavor related genes, which lays an initial background for exploring the mechanism of substrate-based cultivation, in order to improve the quality of tomato in the future. [ABSTRACT FROM AUTHOR]

Iodine is a non-essential element for land plants, but is considered as a beneficial element, related to antioxidant capacity, environmental adaptations and improvement of plant growth. Salinity is one of the more recurrent abiotic stresses worldwide, seriously affecting vegetal production. The aim of this work was to evaluate iodine application (Q products® and KIO3, Quimcasa de México, Naucalpan, Mexico) in strawberry plants under normal and salt stress conditions. Growth, antioxidant content, essential minerals, iodine accumulation and fruit quality were evaluated. The results showed that, under stress conditions, the application of Q products increased ascorbate peroxidase (APX) and catalase (CAT) activity as well as glutathione (GSH) content and yield in fruit, without avoiding biomass loss; with the application of KIO3 an increase in GSH and APX activity as well as P and K concentrations were obtained. In leaves an increase in P, Ca, Mn and iodine accumulation was evidenced with the application of Q products, and an increased concentration of ascorbic acid and iodine with KIO3 treatments. Under normal conditions in fruits, the application of Q products increased phenolic compounds synthesis; additionally, an increase in Ca and Mn concentrations was shown. KIO3 application increased the firmness and Mn. In leaves, the application of Q products increased chlorophyll a, b and calcium. In conclusion, the application of iodine improves the quality value of strawberries under normal conditions and provides an enhancement of salt stress tolerance. [ABSTRACT FROM AUTHOR]

Climate, soil and tree water status, fruit yields and quality of 'Valencia' orange trees were monitored over five consecutive seasons (2007–2012) to study the effects of irrigation placement or volume. Three irrigation treatments were imposed: conventional irrigation (CI, 100% of crop evapotranspiration on both sides of the rootzone), partial rootzone drying (PRD, 50% of CI water only on one alternated side of the rootzone) and continuous deficit irrigation (DI, 50% of CI water on both sides of the rootzone). Yield parameters were generally not affected by PRD, and only yield per tree was lower in DI than CI trees. Fruit size and juice content were also reduced by DI, and not by PRD. Both PRD and DI increased juice soluble solids and acidity, vitamin C and carotenoid concentrations, as well as fruit, juice and sugar productivity per unit of irrigation water. Overall, the straight reduction of irrigation volumes by ~55% (DI) induced an average of 4.4% leaf dehydration, which caused significant fruit size reductions and a 3.4% reduction in juice yield, corresponding to a loss of about 2.6 tons of juice and 261 kg of sugars per hectare and year. On the other hand, water savings of about 2 mega liters per hectare and year with PRD caused a mild 2.3% leaf dehydration and mainly fruit quality improvements, indicating that PRD is a sustainable irrigation strategy for 'Valencia' orange. [ABSTRACT FROM AUTHOR]