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To exploit the full potential of plants, it is essential to provide an adequate water balance during critical growth stages. With knowledge of the substrate’s matric potential, it is possible to realistically measure the amount of water available to the plant. The objective of this research is to study the effect of the matric potential of the substrate on the growth of beans, lettuce, sweet peppers, watermelon, and cauliflower plants. The research goal was to evaluate the effect of the matric potential on the main fertigation parameters of horticultural plants. The plants were cultivated at the University of Almería (Spain) in a controlled chamber in a pot with 250 mL of coconut fiber substrate from block propagation. For treatments T15, T30, T45, and T60, new irrigation was applied when easily available water (EAW) depletion levels of 15, 30, 45, and 60% were reached, respectively. The efficiency of the use of water (WUE), nitrate (NUE), and potassium (KUE) was measured. From T15 to T60, a significant effect was found for the absorption of water, nitrate and potassium, WUE, NUE, and KUE. T60 reduced the plant growth by half. The largest growth was between 15 and 30% of the level of use of EAW. Two different models were constructed according to each plant. It is possible to have a small depletion in the available water and still have plant growth, if there is a balance between the air and water needs of the substrate.

The response of pepper (Capsicum annuum L.) to Ammonium-N was studied in a multispan greenhouse under soilless culture using coir fiber as substrate. Ammonium-N application rates were 0, 2, 4, 6 an...

Recent studies show that vegetables at early stage of development contain higher amounts of phytonutrients and minerals, and lower amounts of nitrates than at fully developed stage. Nevertheless, the effects of some spectrum light on the carotenoid content of lettuce microgreens are unknown. Three different LED lamps were checked: (i) artificial white light (T0); (ii) continuous light-emitting diodes with longer blue-wavelength (T1), and (iii) continuous light-emitting diodes with longer red-wavelength (T2). Different lettuce cvs. were grown under the above described lamps. Plants were collected after 10, 15, 35 and 50 days from planting to produce sprouts, microgreens, initial baby leaf, and baby leaf, respectively. Response to different continuous spectrum lights related to productivity and nitrate content was variable for the different plants. Accumulation of nitrates at initial stages in plant tissues was clearly lower than at final stages of crop development, ranging from 50.2 to 73.4 mg 100 g1 fresh weight for T2. Lettuce consumption is preferable at microgreen stage in comparison with baby leaf stage. Nitrate amounts at microgreen stage were lower than in baby leaf stage, and this content was inversely correlated with carotenoid content, which in tissues was higher at microgreens stage influenced by LED.

Tomato fruit possess high lycopene concentrations, which increases after reaching the breaker stage of ripeness. Light emitting diode (LED) systems have emerged as a clean and efficient artificial lighting technique for use in horticulture. The objective of this research was to examine the effect of LEDs on postharvest and lycopene quality parameters. The effects on quality parameters were significantly different depending on the tomato fruit cultivar. The commercial and organoleptic quality parameters most affected were firmness and titratable acidity. The lycopene concentration in all tomato cultivars increased between 30% and 60% when they were exposed to LED light compared with dark-exposed fruit. One hour of LED light exposure per day during the postharvest phase of fruit increased commercial and organoleptic parameters, and increased the lycopene concentration. Fruit exposed to LED light with a high red:far red (R:FR) light ratio had increased firmness compared with those exposed to other types of white LED light. The highest R:FR ratio used in this study resulted in fruit with higher titratable acidity than those exposed to lower R:FR ratios. Overall, the results of this study demonstrated that the postharvest exposure of tomato fruit to LED light with a high R:FR ratio induces lycopene synthesis, with lycopene concentrations being 41% higher in comparison with exposure to darkness and 24% higher in comparison with exposure to other LED lighting conditions.

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.

The aim of this work was to assess the seed oils of different Borago species as sources of bioavailable γ-linolenic acid (GLA) by establishing its positional distribution within the triacylglycerol (TAG) structure. To this end, seeds of wild and farmed Borago species were collected and analysed. The highest GLA percentage of total fatty acids (FA) was found in B. morisiana and B. pygmaea (23.1 and 22.9% GLA of total FA, respectively). Other endemic Borago species (B. trabutii and B. longifolia) show a lower GLA content (18.9 and 19.0% of total FA, respectively). Oil content in seeds of B. officinalis ranged from 14.4 to 20.3%, while the GLA percentage of total FA was 15.7–19.4%, which leads to a 2.3–3.7% GLA range in the whole seeds. For endemic Borago, such amounts were 5.6, 5.0, 3.9, and 3.0%, for B. morisiana, B. pygmaea, B. trabutii, and B. longifolia, respectively. The distribution of FA in the sn-2 position of TAG was assessed by enzymatic hydrolysis reaction. The best regiospecific index was found in B. longifolia (0.8) and B. officinalis (1.0). This study provides useful data on novel GLA-rich Borago seed oils, which have potential use in the food and pharmaceutical industries.

Borage oil contains γ-linolenic acid (GLA, 18:3n-6), and significant amounts of tocopherols, sterols and squalene. However, data on phenolics are absent for most Borago species, while such compounds are relevant for improving human health. In this work, seeds of all endemic-wild Borago species and wild and farmed B. officinalis were surveyed for phenolic compound composition and in vitro antiproliferative activities. Phenolic analyses were conducted by HPLC-DAD and LC-MS, and antiproliferative activity were checked by the MTT assay. Besides a flavonol (kaemferol), 13 phenolic acids were identified and quantified. Among B. officinalis samples, the highest amounts of total phenolics and rosmarinic acid were found in the warmest and southernmost localities. Rosmarinic acid ranged from 12.21 (B. officinalis ‘Alba’ B2) to 105.06 mg/100 g seed (B. longifolia). Ferulic acid was also found in all Borago species, ranging from 1.38 in wild B. officinalis to 55.98 mg/100 g seed in B. longifolia. The MTT assay showed dose- and time-dependent inhibitory effects of Borago extracts on HT-29 cancer cells, with GI50 values within the 250–300 μg/mL range after 72 h of cell exposure to seeds extracts. Due to the occurrence of some compounds lacking antiproliferative activity in the crude phenolic extract, as evidenced by 1H NMR spectrum, the antiproliferative activity of the phenolics-containing extracts was lower than that obtained due to pure phenolics. This work constitutes the first approach to evaluate the phenolic composition of all Borago species and provides arguments for using endemic-wild Borago taxa by the pharmaceutical, cosmetic and food industries.

Made available in DSpace on 2018-12-11T17:15:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-11-08 An experiment was conducted to develop a model of vegetative growth based on the nitrate concentrations in nutrient solutions using the nutrient film technique and to determine the best cultivar for each concentration. The chicory cultivars (“Pão de Açúcar,” “Folha Larga,” “Precoce de Trieste” and “Catalonha”) and the subplots corresponded to different nitrate concentrations (6.68, 10.0, 13.32 and 16.64 mmol L−1). There was an interaction between the evaluated factors, such that there was no similarity in the response of the chicory cultivars to the N concentrations in the nutrient solution. The most productive chicory cultivar was “Pão de Açúcar,” which exhibited 10.5% higher productivity than the average, and the least productive was “Folha Larga,” which showed approximately 8.5% lower productivity than the average. Departamento de Produção Vegetal Faculdade de Ciências Agrárias e Veterinárias Campus de Jaboticabal UNESP–Universidade Estadual Paulista Departamento de Agronomía Universidad de Almería Departamento de Produção Vegetal Faculdade de Ciências Agrárias e Veterinárias Campus de Jaboticabal UNESP–Universidade Estadual Paulista

An intercrop is studied here as a new way of farming in soilless systems within a protected environment. To estimate the efficiency of intercropping in this cultivation system, an experiment was conducted to evaluate the effect of the electrical conductivity (EC) of the nutrient solution (2.0, 2.5, and 3.0 dS·m−1) on lettuce and tomato plants and on the agronomic and economic feasibility of the intercrop compared with monoculture. The results indicated that a moderate increase in EC from 2.0 to 3.0 dS·m−1 did not exert any important effect on tomato plant production or quality but did cause a decrease in lettuce yield in both the first and second crops. Intercropping was only feasible for lettuce when the tomato and lettuce plants were transplanted on the same day. The highest tomato (G class) and lettuce yields were achieved at an EC of 2.5 dS·m−1; this condition resulted in the highest intercrop profitability (0.53 €·m−2 more) when compared with tomato monoculture.

Greenhouse tomato production is shifting to meet emerging consumer needs. Increasing environmental concerns have pressured growers to supply high-quality vegetables using sustainable production methods. The utilization of adapting fertigation to production conditions and/or nutrient solutions of moderately high conductivity seems promising in providing high yields of superior quality while limiting the emission of nutrients to the environment in greenhouse tomato crops. A tomato crop was grown in soilless culture with various levels of electrical conductivity (EC), 2.2, 3.5, and 4.5 dS·m−1, adjusting the final nutrient concentration and maintaining nutritional balance. The effect of nutrient solutions with moderately high EC on fertigation parameters and the emission of nutrients to the environment, total crop productivity, distribution of fruit sizes, and dietary and organoleptic qualities were measured. Nutrient solutions of moderately high EC decreased total and commercial yield, with an average reduction from 5% to 19% and 3% to 22%, respectively. A considerable decrease in extra large and large fruits, with an average reduction from 69% to 42%, was also observed. Nonetheless, dietary-related metabolites were significantly increased at the highest EC values: lycopene (6.3%), ascorbic acid (8.8%), total phenolics content (8.3%), and total antioxidant activity (11.1%). EC values of 3.5 and 4.5 dS·m−1 are not widely used in commercial production but are frequently measured in drainage solutions in open hydroponic systems and discarded solutions in closed systems, mainly because of the use of poor-quality water and the accumulation of excess nutrients.

The aim of this work was to establish the richness in γ-linolenic acid (GLA, 18:3n6) and stearidonic acid (SDA, 18:4n3) of several Sardinian Boraginaceae species. To this end, seeds of selected species were collected from their natural habitats and analysed. The highest GLA contents were found in the seed oils of two endemic Borago taxa, i.e. B. morisiana (24.4 and 24.6% GLA of total fatty acids for samples from San Pietro Island and Sardinia Island, respectively), and 22.9% GLA for B. pygmaea. Both Borago species contained more GLA than B. officinalis collected in the same ecosystems. SDA was found in significant amounts in Echium plantagineum seed oil from the Lattias Mountains (15% SDA of total fatty acids). It is notable that both Borago GLA-rich species are under threat of extinction, thus revealing the importance of the preservation of the natural Sardinian ecosystems for endangered species and human health.

The benefits of silicon for different plant species have been described in many studies in both soilless and traditional soil culture systems. The aim of this work was to quantify the effect of Si on leaf cuticles under different fertigation regimes and the relationship of this effect to water, potassium and nitrate absorption, vegetative growth and plant protection. Cucumber, melon and pepper plants were transplanted into coconut fiber containers with Si in the nutrient solution at 0.6 mM (+Si) and without Si (-Si) under optimal fertigation (OF) and moderate deficit fertigation (DF) conditions. Absorption of water, nitrate and potassium, vegetative growth, leaf firmness, loss of water through cuticle transpiration, cuticle thickness, number of trichomes and Si content in the epidermis and trichomes were measured. Trichome numbers, cuticle thickness and Si content were examined using light and SEM microscopes equipped for X-ray microanalysis. Resistance to two pathogens, Botrytis cinerea and Erysiphe cichoracearum, was also measured. The results show a loss of growth in the three cv. under DF that was alleviated when Si was supplied in the nutrient solution. +Si significantly improved water absorption and decreased leaf loss, which may explain the improvement shown in the growth parameters. +Si showed clear and significant growth increases in both the epidermis and the cuticle, which could justify both the observed greater resistance to diseases and the lower rates of water loss from the leaves. The three cv. showed high concentrations of Si in the trichomes, even under -Si treatments with a mean Si concentration lower than that in the +Si treatments.

Borage is a well-known plant of great importance in human nutrition and health. Expanding knowledge of particular plants that have anti-cancer products is a global concern. There is substantial information regarding the benefits, presence and extraction of gamma linolenic acid (GLA) in different plants around the world, especially in borage seeds. However, there is little information concerning the effects of the salinity of the nutrient solution on the growth and presence of GLA in borage seeds. The objective of this work was to determine the optimal salinity of the nutrient solution for obtaining GLA in soilless cultivation systems. Borage plants were grown in coconut fibre and provided three treatments of nutrient solution of 2.20, 3.35 and 4.50 dS m−1, increasing solution salinity with the standard nutrient solution of concentrated macronutrients as a reference. Vegetative growth, seed production and GLA ratio were measured. The results of vegetative development and GLA production doubled and tripled with the increase in salinity of the nutrient solution, respectively.

The growth and essential oil (EO) production of parsley were evaluated in response to salinity and nutrient solution concentrations in a soilless culture. Parsley plants that were 60 days old were potted in a coconut fiber and peat moss medium and were treated with four different nutrient solutions, including T1, T2, T3 and T4. The T1 nutrient solution was the standard, the T2 and T3 solutions contained incremental macronutrient concentrations with an electrical conductivity (EC) of up to 2.2 and 3.2 dS m−1, respectively, and the T4 solution was the same as T2 but with sodium chloride (NaCl) and an incremental macronutrient concentration with an EC of 3.2 dS m−1. Next, these plants were grown for 90 days in a greenhouse with natural daylight in Nador, Morocco. Shoot and root growth significant decreased with increasing EC. However, the salinity that resulted from the addition of NaCl did not affect plant growth in the nutrient solutions. The optimum obtained growth and EO production were 1.2 and 2...

Made available in DSpace on 2018-11-26T15:44:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-07-05 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Brazilian Agricultural Research Corporation The interactive effects of N (6, 9, 12 and 15 mmol L-1) and K (3, 5, 7, and 9 mmol L-1) concentrations in nutrient solutions were evaluated on bell pepper grown in a coconut-coir substrate and fertilized without drainage. An additional treatment with drainage was evaluated using N and K concentrations of 12 and 7 mmol L-1, respectively. The hybrid Eppo cultivar of yellow bell pepper was cultivated for 252 days beginning 9 November 2012. Electrical conductivity (EC), the N and K concentrations in the substrate solution, marketable fruit yield, total dry weight and macronutrient concentrations in shoots were periodically evaluated. Fruit production was lower in the system without drainage, regardless of the N and K concentrations, compared to the recommended 10-20% drainage of the volume of nutrient solution applied. Higher K concentrations in the nutrient solution did not affect plant production in the system without drainage for the substrate with an initial K concentration of 331.3 mg L-1. Fruit yield was higher without drainage at a nutrient-solution N concentration of 10.7 mmol L-1. The upper EC limit of the substrate solution in the system without drainage was exceeded 181 days after planting. Either lower nutrient concentrations in the nutrient solution or a drainage system could thus control the EC in the substrate solution. Empresa Pesquisa Agr & Extensao Rural Santa Catar, Estacao Expt Cacador, Cacador, SC, Brazil Univ Estadual Paulista, Dept Prod Vegetal, Fac Ciencias Agr & Vet, Sao Paulo, Brazil Univ Nacl Agr La Molina, Fac Agron, Dept Fitotecnia, Lima, Peru Univ Almeria, Dept Agron, Escuela Super Ingn, Almeria, Spain Univ Estadual Paulista, Dept Prod Vegetal, Fac Ciencias Agr & Vet, Sao Paulo, Brazil FAPESP: 2011/17524-7

This study evaluated the effects of salinity on thyme (Thymus vulgaris) and lavender (Lavandula angustifolia) plants grown alone and in combination with each other. After transplanting, two-month-old plants received nutrient solutions supplemented with 0, 50, and 100 mM sodium chloride (NaCl) for 21 d. Thyme and lavender grown alone were each more tolerant to salt stress than thyme and lavender grown together. In the 100 mM NaCl treatment, all lavender plants grown with thyme died. In thyme, the carbon (C) and nitrogen (N) contents of the roots increased. Ethylene production in thyme was stimulated by salinity only in plants that interacted with lavender. However, in lavender, ethylene production was not influenced by the presence of thyme. The production of essential oils (EOs) was increased by salinity in thyme plants, whereas the EO production of lavender plants depended on the presence of thyme.

Endemic Borago species contain notably high amounts of γ-linolenic acid (GLA, 18:3n6), the main bioactive fatty acid of borage oil. However, little is known about the occurrence of nutritionally relevant phytochemicals in seed oil of such plants. This work was designed to test the occurrence of important phytochemicals (tocopherols, sterols and squalene) in the seed oil of Borago species. To this end, seeds of endemic-wild and farmed Borago species were collected and analyzed. All compounds were analyzed by HPLC-diode array detector, while sterol and squalene peaks were confirmed using a LC–MS device and a library software. The highest amounts of tocopherols were found in two endemic Borago species: B. pygmaea and B. morisiana, with 514 and 296 mg/100 g oil, respectively. Squalene was predominant in B. officinalis collected in Tunisia and B. morisiana (3.9 mg/100 g seeds). The main sterols were Δ5-avenasterol, campesterol, and β-sitosterol, which were especially high in B. morisiana and B. pygmaea, with 107 and 102 mg of total sterols by100 g of seeds, respectively. The latter species are noteworthy GLA producers. The study suggested that oils from the endemic species are more nutritionally advantageous than those from the common cultivated borage (B. officinalis) and other current sources.

□ Plants from 60-day-old Lime Thyme (Thymus citriodorus) cuttings were potted in a medium of coconut fiber and peat moss and were treated with three different nutrient solutions: T1, T2, and T3. T1 was a standard nutrient solution; T2 was incremented with macronutrients up to an electrical conductivity (EC) of 2.8 dS m−1; and T3 was the same as T1 but incremented up to an EC of 2.8 dS m−1 with sodium chloride. The plants were then grown for 90 days in a greenhouse with natural daylight in Almeria, Spain. Root growth was not affected by the treatments. The dry weight of the leaves and the total dry weight of the plants benefited from the salinity. The specific salinity of the sodium chloride negatively affected growth compared to the same salinity in the complete nutrient solution.

Salinity is well known to reduce plant growth and yield by reducing water availability; it does so by interfering with both nutrient uptake and translocation. The objective was to determine the nitrate and potassium contents in xylem sap and the root-shoot transportation of both as a function of the salinity of the nutritional solution provided. We compared NO3-and K+ contents and flux in xylem sap collected from cut stems of tomato seedlings, based on electric conductivity (EC) tests among five nutrition solutions for soilless crops ranging from medium to high salinity. The EC was 2.2, 3.5, 4.5, 6, and 12 dS m-1. The concentration of nitrates and potassium in the xylem sap remained constant, while the external concentration in the rhizosphere varied greatly. Notwithstanding, the xylematic flux was strongly affected by the salinity of the nutritional solution: at maximum salinity, EC reached 3.5 dS m-1; at minimum, EC was 12 dS m-1. For similar reasons, the longest NO3- and K+ transportation distance between root and shoot was achieved when the EC read 3.5 dS m-1, but was reduced by up to 80% when EC was 12 dS m-1.

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...

Raw salad vegetables are typically consumed without being cooked. This study compared peracetic acid mix (PAA) and sodium hypochlorite (SH) as disinfectants on vegetables postharvest. Tomato, sweet pepper and cucumber were evaluated in three different experiments: (1) determination of organoleptic characteristics of vegetables by consumer preference; (2) disinfectant capacity comparison of PAA versus SH; and (3) measurement of phytotoxicity of disinfectant products, expressed as alteration of the surface of sweet peppers. Each treatment was replicated four times, and all procedures simulated the procedures carried out in industry. No differences in fruits washed with different treatments were found by the panel. Starting at Day 15, the peracetic acid mixture (PAA) showed better disinfection performance than sodium hypochlorite (SH). The results indicate that the peracetic acid mix is better for washing fruit and improving postharvest life as it is better for the environment (due to low toxicity) and for health safety and does not affect the taste characteristics of the fruit.

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.

Root temperature may affect the production of greenhouse vegetables under soilless culture. Four independent experiments were carried out over two consecutive crop cy- cles using two different substrates: rockwool and coconut coir waste. Three heating treatments were applied: non heating (T0), nutrient solution at 12-16 ◦ C (T1), and at 18-22 ◦ C (T2). The experiments were carried out in greenhouses in Almer´ ia (SE Spain) on cucumber and melon. Mean substrate and air temperature were not affected by the treatments. Under conditions of nutrient solution heating EC and percentage of drainage volume decreased, while water and mineral nutrient absorption increased. However, re- sults showed great differences between both crops and substrates. A significant decrease in nitrate and phosphate emission from the substrates was also recorded, especially in rockwool substrate. Few effects were observed concerning yield and fruit quality param- eters, but in rockwool-grown melon early yield was enhanced. It follows that nutrient solution heating is a low-cost and environmentally friendly method of increasing early melon yield.

Oxygen deficiency has an immediate effect on both water and nutrient uptake, the yield of the whole plant under different soilless culture is affected. The oxygen level required for the respiration of the root system then becomes a limiting factor as much in soil culture as in soilless culture. The total area of soilless crops in SE Spain today is estimated to be about 5000 ha. The objective of this experiment was to study the effect of potassium peroxide as an oxygen generator on vegetable crops growing in commercial substrates and to determinate the supply fraction for its use. Bioassay was used to determinate the fraction of potassium peroxide needed. Three greenhouse experiments were conducted in soilless culture with perlite and rockwool. Sweet pepper, melon and cucumber crop were supplied with potassium peroxide through fertigation to increase the oxygen content for one day per week. There were treatments: one with (T1) and the other without potassium peroxide (T0) in the nutrient solution. Fertigation parameters, yield and its quality were measured. Bioassay suggested that one gram per litre is the best fraction to use in soilless culture. Yield of sweet pepper was about 20% higher for T1 than T0 and 15% for melon; there was no significant difference in cucumber plants.

Made available in DSpace on 2018-12-11T17:25:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-01 An experiment was carried out from February 25 till April 10 of 2010 at the Jaboticabal campus of the Paulista State University (UNESP), state of São Paulo, Brazil, viewing to find out which would be the optimum and the phytotoxic levels of iron in the nutrients solution for common chicory (Cichorium intybus) plants. Iron concentrations in the nutrients solution were of 0.9, 2.7, 8.3, and 25 mg L−1. These treatments were replicated 4 times and the experimental units were distributed according to a randomized complete block design. The nutrient film hydroponic technique (NFT) was used. Growth parameters such as plant height and number of leaves as well as reproductive parameters such as green and dry mass production were evaluated. The optimal concentrations were found to be between 2.7 and 8.3 mg L−1 of iron in the nutrients solution. The concentration of 25 mg L−1 caused toxicity, although no visual sign of iron in excess was observed. Plant Production Departament, Universidade Estadual Paulista (UNESP) Departamento de Agronomía, Universidad de Almería Plant Production Departament, Universidade Estadual Paulista (UNESP)

Soils with high gypsum content support specific vegetation, indicating a soil environment to which gypsophile plants have adapted. The goal of the present work was to compare the chemical composition, mainly the availability of micronutrients, of the rhizosphere soil of plants growing in gypsiferous soils to that of plants growing in nongypsiferous soils. Rhizospheres of populations of gypsophile (true and facultative) and nongypsophile plants were sampled, and concentrations of SO 2- 4 , Ca 2+ , Mg 2+ , K + , Fe, Cu, Mn, and Zn were determined. Sulphates and Ca 2+ concentrations were higher in the rhizosphere of gypsophile plants, either true and facultative, than in the rhizosphere of nongypsophile plants. The electrolytic conductivity (EC) is moderate in all cases (maximum 2.5dS m - 1 ), and pH values (between 7.6 and 7.9) were slightly basic and similar among the sampled rhizospheres. Largest differences were found in the micronutrient concentrations, especially Fe and Mn. Soils holding gypsophile pla...

El objetivo de este trabajo fue evaluar la tolerancia al deterioro y la viabilidad de semillas de maíz en inmersión en agua caliente. Se evaluaron tres cultivares de maíz: País Tuxpeño (PT), X´nuuknal (X) y Sinaloa (S) que se sometieron a 0, 2, 4, 6 y 8 segundos de inmersión en agua a 100°C, en la producción de germinados para forraje. El estudio se realizó en Conkal, Yucatán, México en junio de 2011. Las variables evaluadas en semillas fueron: peso inicial (PIS), porcentaje de germinación (PG), número medio de días a germinación (NMDG) e índice de velocidad (IVG); en plántulas: peso fresco (PF), seco (PS) y la relación producción de biomasa por unidad de peso de semilla (PF:PIS). Los resultados mostraron diferencias significativas (P≤0,05) en todas las variables, excepto en NMDG. El PG fue de 96, 74 y 55% para PT, X y S, respectivamente. La inmersión por 2 s incrementó el PG, IVG, PF, PS y PF:PIS en X y S pero con inmersión por 4 y 6 s estas variables disminuyeron. Por el contrario, el PT inmerso por 2 s disminuyó el PG al 75%, pero con inmersión por 4 y 6 s todas las variables mostraron valores ascendentes. El tiempo de inmersión por 8 s afectó severamente a los tres cultivares, siendo PT el menos afectado ya que el PF solamente disminuyó el 35%, mientras que para X y S el decremento fue de 61% y 42% respectivamente. En conclusión, PT presentó mayor tolerancia al deterioro por inmersión en agua caliente y por tanto, es el más recomendado para la producción de germinados para forraje verde.

The effect of peracetic acid on the vase life and bud opening of cut flowers of Lisianthus was investigated. Eustoma grandiflorum is an attractive cut flower with a considerable length of vase life (usually weeks for freshly harvested stems). It is well known that the addition of sucrose into the vase solution increases significantly the longevity of cut flowers. Two different experiments of vase life were carried out. The first used cultivars of the Mariachi Series: Blue, Green, Blue Picotee, and Pink, whereas the second used Rosita White and Piccolo White 1. The control plants (T1) were supplied with tap water. Treatment 2 (T2) was similar to T1 with the addition of 3% sucrose. In the third (T3) and fourth (T4) treatments, sodium hypochlorite and a stabilized peracetic mixed system (PAA) were added, respectively. The number of flowers that opened from buds between cultivars was significantly different. With the addition of sucrose into the vase solution, a significant increase in longevity was recorded, which was also observed after the addition of both biocides to the respective treatments. This can be extended up to 15% by the addition of sucrose to the vase solution and up to 30% if PAA is incorporated into the vase solution. The results suggest that PAA can be a useful alternative to sodium hypochlorite for vase solutions because it is without the health drawbacks of trihalomethanes. The degradation of PAA is environmentally friendly, because it decomposes to form biodegradable acetic acid and eventually enters the environment as atomic oxygen.

Nitrate accumulation in vegetable represents a serious threat to man's health. Different methods have been reported to reduce the nitrate accumulation in lettuce and other leafy vegetables with or without variation in the yield. The aim of this experiment was to show the different behavior of some cultivars of lettuce using the replacement of N‐NO3 for chloride in the nutrient solution during last week before harvest. The trial was carried out with three lettuce cultivars: Domino, Elvira, and Daguan and took place in southern Spain (Almeria) under greenhouse by NFT. The results indicated a correct method to decrease nitrate content in leafy vegetables and perhaps sulphate could be an anion to study their effect in this way.

The present study was conducted during four consecutive vegetative cycles in deciduous fruit trees of agricultural value, almond, apple, pear, pomegranate, hazelnut, persimmon, and fig. Leaves were sampled on six occasions from the middle third of branches from the entire circumference of the crown at different stages of the vegetative cycle, and analyzed in order to determine levels of total and soluble N, P, K, Ca, and Mg. The changes over time in total and soluble levels of the N‐10P‐K ternary group did not significantly affect the relative proportions of the components. Relative levels of P and N varied slightly in almond, hazelnut, persimmon, and fig. By constrast, antagonism between K and Ca led to significant changes in ion levels in the K‐Ca‐Mg ternary group. The optimal levels of ions varied among the different species. In apple, total N‐10P‐K showed a high optimal value (59–28–15), while soluble N‐10P‐K was comparatively low (30–44–26). The lowest figures for both total and soluble N‐10...

Perennial deciduous plants were studied during their vegetative cycles. Leaves were sampled regularly every 15 days throughout this period in order to determine total and soluble iron (Fe) indices, physiological balances, and micronutrient levels. Analysis of variance and coefficients of variation were high for Fe indices and micronutrients between samples. The values of interaction between variables were not high. The optimium value of total Fe index ranged from 0.72–0.74 in almond to 1.11–1.14 in pomegranate. Optimum values for soluble Fe index ranged from 0.77–0.83 in almond to 1.18–1.29 in pear. Similar ranges were observed for soluble and total micronutrients and ternary groups. The evolution of the physiological ternary groups demonstrates ionic imbalances in apple in total Fe and manganese (Mn) as a result of excess levels of total zinc (Zn) during the final phase of fruit development. During this phase, total and soluble Fe and Mn also show significant interactions in persimmon. In apple,...

Xylem sap extraction from decapitated plants by negative pressure will be discussed in this paper. This method of extraction, in which transpiration is simulated by a negative pressure, uses as a quantitative reference generated by non‐decapitated plants. For this method, several horticultural plant have been used with the main nutritive elements in the sap analyzed by ionic chromatography.

An attempt was made to relate an Fe-index based on levels of nutrients determined in leaves to production of horticultural crops. The Fe-index is defined as follows: $$Fe - index = \frac{{\left( {10P + K} \right)50}}{{Fe}} $$ where: Fe = μg Fe/g dry matter; P= % phosphorus in dry matter; K= % potassium in dry matter.

The concept of active Fe has been seldom applied to the extractable fraction to study its changes through time. Neither its relationships to physiological balance of Fe Index in plants has been investigated to any extent. The study reported here was conducted on Castanea sativa Miller trees, autoctonous, not grown by man, as the relationships il‐plant is better balanced. In this work we studied the contents and changes of P, K, Fe, Mn and Zn which are found in extractable form in leaves, the balances of Fe‐Mn‐Zn, and the Fe Index obtained from data of the extractable fraction and their changes throughout the vegetative cycle. The data obtained were related to those obtained from the analysis of the total plant to study their significance in the foliar analysis values, and the possibility to diagnose Fe disorders from balances Fe‐Mn‐Zn and Fe Index obtained from the extractable fraction. Likewise, the relationships among the extracted nutrients and the total present in the foliar tissues were also...

The management of water and nutrient ions, such as nitrate, has been studied extensively in recent decades. Increasingly efficient models have been developed for the use of water and nutrients through the automation of fertigation techniques. The application of a fertigation volume for a duration four times longer than applied on the control was evaluated. In Almería (Spain), one pepper crop and two tomato crops—with and without grafting—were grown between Oct. 2013 and June 2014 in a soilless system with a coir substrate. The effects on root growth, plant growth, production, and quality were measured. The following parameters for the fertigation of the nutrient solution and drainage were recorded: % drainage volume, electrical conductivity (EC) of the nutrient solution, pH, and concentration of nitrates and potassium. The absorption of potassium and nitrate, and the nitrate emissions of the drainage were estimated. The results showed an increase in the root volume and an improved distribution in the cultivation unit for the treatment application in the pepper crop. Slowing the applied fertigation improved the absorption of water and nitrates, and the production in the ungrafted tomato and pepper crops, while the grafted tomato crop was unaffected. Nitrate emissions were lower in the evaluated treatment of the pepper and ungrafted tomato crops. The fruit quality parameters were unaffected.

Inadequate oxygenation of the nutrient solution (NS) in recirculating hydroponic systems leads to root hypoxia in several plants as a result of low oxygen solubility, and this is most notable in warm climates. Hypoxia affects crop nutrient and water absorption and results in reduced crop yield. However, increased air supply to the NS serves as a source of oxygen for the roots. To evaluate the incorporation of oxygen into the system, we varied the slope of 14-m long containers from 2% to 4% and applied zero, one, two, or three gaps of NS. The channel width measured 10 cm and was equidistant from the end points. The effect of the dissolved oxygen in the NS was measured by the production of a tomato cultivar. The oxygen dissolved in the NS was 5% greater in the channels with a 4% slope compared with those with a 2% slope. The channels that included the gaps incorporated a higher quantity of dissolved oxygen during cultivation. In the middle of the day, the available oxygen was the limiting factor for the yield. The best results were obtained with a steeper slope, and gaps also improved the tomato yield. More rapid changes in NS were associated with a higher quantity of dissolved oxygen.