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Selenium (Se) is an essential micronutrient for humans, but most foods are Se deficient, mainly because of its low content in the soil. A Se-deficient diet results in increased susceptibility to cardiovascular disease, cancer, and hyperthyroidism. Agronomic biofortification is a good alternative to increase Se in food. This study investigated the effect of Se on the growth, yield, and biofortification of the rocket. Plants were grown in a hydroponic system. Seven Se concentrations (0, 10, 20, 30, 40, 50, and 60 µM) were evaluated using sodium selenate. Growth, yield, lipid peroxidation, hydrogen peroxide content, and the enzymatic activity of catalase and ascorbate peroxidase were influenced by the Se concentration. Considering the evaluated parameters, 10–30 µM Se promoted the best results, and with 20 µM, the higher yield. Rocket plants treated with Se in the nutrient solution were biofortified, showing Se contents of 598.96 to 1437.56 mg kg−1 in the dry mass, higher than plants cultivated in a nutrient solution without Se, which presented 167.84 mg kg−1 of Se. Se concentrations of 10–30 µM in the nutrient solution were beneficial for rocket plants, while concentrations above 50 µM were toxic to the plants.

One-fifth of the world's population consumes too little zinc (Zn) causing deficiencies that can damage cells, stunt growth, and decrease immune response. This study evaluated the effect of time on the priming of beet seeds, in solutions enriched with Zn, on physiology, growth, production, and root biofortification. Two greenhouse experiments were conducted during spring 2015 and autumn 2016. In each experiment, 24 treatments were tested which comprised various combinations of three Zn concentrations (0, 10, and 30 mg mL-1), two Zn sources (sulphate and chloride), and four time periods (12, 16, 20, and 24 h), arranged in a randomised block design with four replicates. The concentration of Zn, mainly as sulphate, affected all parameters evaluated in the beet plants, such as fresh and dry root mass, photosynthesis, and root Zn concentration (biofortification). Compared to the control, fresh root mass increased 70 and 100 g per plant with 10 mg mL-1 of Zn during the experiments in 2015 and 2016, respectively. The same concentration for 16 h produced the highest Zn concentration in the roots, achieving 121 and 42 mg kg-1 in 2015 and 2016, respectively. Priming seeds in solutions enriched with Zn, thus, benefited the physiological response of the beet plants by promoting increases in growth, production, and biofortification of beet roots. Therefore, this method can be used to biofortify beet plants agronomically, regardless of the Zn source. RESUMO Uma quinta parte da população mundial consome pouco zinco (Zn), causando deficiências que podem causar danos celulares, retardo no crescimento e diminuir o sistema imunológico. Nesse trabalho avaliou-se o efeito do tempo de condicionamento osmótico de sementes de beterraba em soluções enriquecidas com Zn sobre a fisiologia, o crescimento, a produção e a biofortificação da raiz. Dois experimentos em estufa foram conduzidos durante primavera de 2015 e outono de 2016. Em cada experimento foram testados 24 tratamentos os quais compreenderam as combinações de três concentrações de Zn (0, 10 e 30 mg mL-1), duas fontes de Zn (sulfato e cloreto) e quatro tempos (12, 16, 20 e 24 horas), sob arranjo de blocos casualizados com quatro repetições. A concentração de Zn, principalmente como sulfato, afetou todos os parâmetros avaliados nas plantas de beterraba, massa fresca e seca de raiz, fotossíntese e a concentração de Zn na raiz (biofortificação). Em comparação ao controle, a massa fresca da raíz incrementou 70 e 100 g por planta com 10 mg mL-1 Zn durante os experimentos de 2015 e 2016, respectivamente. A mesma concentração por 16 horas provocou a maior concentração de Zn nas raízes atingindo 121 e 42 mg kg-1 em 2015 e 2016, respectivamente. Assim, o condicionamento osmótico de sementes em soluções enriquecidas com Zn, melhora as respostas fisiológicas das plantas, promovendo incrementos no crescimento, na produção e na biofortificação das raízes de beterraba. Portanto, esse método pode ser utilizado para biofortificar agronomicamente plantas de beterraba, independente da fonte de Zn.

The effect of pH and silicon (Si) in the nutrient solution on the vegetative development of 2-year-old blueberry plants (Vaccinium corymbosum L. cv. Ventura) was studied. Two independent experiments were performed on coir fiber (CF) and sand as substrates. In experiment 1, Si was applied in the nutrient solution at a dose of 0.0, 0.3, 0.6, and 1.2 mm. In experiment 2, plants were treated with nutrient solution at pH 4.00, 4.75, 5.50, and 6.25, using two sources of acidification: nitric acid and citric acid. The parameters of plant growth, foliar surface, and stem biomass were measured. With the application of 1.2 mm Si to CF, plant height registered a significant increase of 8%, and shoot dry and fresh biomass increased by 21% and 25%, respectively. The results of experiment 1 indicated that the application of Si benefits the vegetative growth of blueberry plants in CF, but no effect was observed in the sand substrate. In the results of experiment 2, the pH level of 6.25 in CF decreased the dry weight of stems and leaves by 21% and 18%, respectively. A significant increase in the pH range of 4.00 to 5.50 was recorded in both the citric acid and nitric acid treatments, but these significant effects were not found in sand. Citric acid presented a similar behavior to nitric acid, which indicates that it can be a good source of acidification in organic and ecologically friendly crops.

Rocket (Eruca sativa Mill.) is a green leafy vegetable that is increasingly used as an ingredient in salad. The floating system is a way to grow this crop, at high density from sowing to harvest and easy to use in relation substrate culture, and it is well known water culture can be limited by hypoxia. Few studies have examined the use of peroxides or peracetic acid in nutrient solutions as a source of oxygenation. The aim of the study was to evaluate the rocket grown in substrates as compared to the floating system, with a stabilized mixture of peracetic acid in the nutrient solution. The experiment was carried out in and Talca (Chile) from October to November 2008. The treatments were substrate culture perlite and composted pine bark (1:1); floating system with trays filled with the same substrate and 0, 40 and 80 mg·L−1 of stabilized peracetic acid mix (PA). The fresh and dry weight of rocket leaves at harvest we evaluated. We recorded total nutrient solution uptake; the average dissolved oxygen; pH an...

Global reduction of chemical deposition into the environment is necessary. In protected horticulture, different strategies with biodegradable products are used to control pathogens. This review presents the available tools, especially for the management of protected horticultural species, including vegetables and ornamental plants. An analysis of the potential for degradable products that control pathogens and also encourage other productive factors, such as oxygen in the root system, is presented. Biosecurity in fertigation management of protected horticulture is conducted by using peroxyacetic acid mixtures that serve three basic principles: first, the manufacture of these products does not involve polluting processes; second, they have the same function as other chemicals, and third, after use and management there is no toxic residue left in the environment. The sustainability of protected horticulture depends on the development and introduction of technologies for implementation in the field.

Wettability of growing medium in horticulture is an important practical factor of this industry. With a proper choice and a right application, wetting agent in the nutrient solution would improve wettability and some other physical properties of growing media. The aim of this study was to evaluate the effects on some physical properties of new and reused rockwool and coconut coir dust substrates with different doses of wetting agent (2, 10, 20, 100, 200, 1000, 2000, 10,000 and 20,000 mg L−1) applied to the nutrient solution and their effects measured by using bioassays. The wetting agent was ether poly-ethylene-glycol nonil-phenol with 20% (w/v) as an active ingredient of a non-ionic surfactant. Bioassay results showed differences among species. For this, the method can be suggested as a good tool to be utilized through fertigation in soilless crops; however, other studies should be proposed for each species in particular. Except to the 2 mg L−1 wetting agent content in reused coir waste, the total water-holding capacity increased with the wetting agent. With 2 mg L−1 wetting agent content there was an important and significant increase the easily available water (over 600%) in both substrates (including the reused ones), while higher doses show no significant differences. The effect of adjuvants added through fertigation is directly dependant on the substrate type evaluated. The substrate reutilized after one crop, reduces the air capacity and increases the easily available water and total water-holding capacity. 2 mg L−1 is the wetting agent concentration more adequate in coir waste and rockwool.

The consumption of fruits and vegetables is accepted to be one of the strategies to reduce risk factors for these diseases. The aim of this study was to examine potential relationships between the antioxidant and the antiplatelet activities in green mature and fully ripe (red) tomatoes and of lycopene-rich byproducts of tomato paste processing such as pomace. The total phenol content of tomato components was the highest in peels, pulp, and in the mucilaginous myxotesta covering the tomato seeds with values36.9±0.8,33.3±00.5, and17.6±0.9 mg GAE/100 g, respectively (P<0.05). Tomato peels had the highest antioxidant activity, both, as measured by the FRAP (46.9±0.9 μmol Fe+2/g,P<0.05) and the DPPH assays (97.4±0.2%, 1000 μg/mL,P<0.05). Pomace extracts showed the highest antiplatelet activity induced by ADP, collagen, TRAP-6, and arachidonic acid. While the maturation stage of the tomato fruit affected the antioxidant effect, antiplatelet activity was independent of fruit ripeness. Finally, based on the present results, tomato and its byproducts may be considered as a valuable source of antioxidant and antiplatelet activities.