Composition Of Nutrient Solution Research Articles

Establishing optimal nutrient solution compositions for watermelon cultivation in open or closed soilless crops

Establishing optimal nutrient solution compositions for watermelon cultivation in open or closed soilless crops

From urine to food and oxygen: effects of high and low NH4+:NO3- ratio on lettuce cultivated in a gas-tight hydroponic facility.

In situ production of food, water and oxygen is essential for long-duration human space missions. Higher plants represent a key element in Bioregenerative Life Support Systems (BLSS), where crop cultivation can be based on water and nutrients recovered from waste and wastewater. Human urine exemplifies an important waste stream with potential to provide crops with nitrogen (N) and other nutrients. Dynamic waste composition and treatment processes may result in mineralized fractions with varying ammonium (NH4 +) to nitrate (NO3 -) ratios. In this study, lettuce was cultivated in the unique ESA MELiSSA Plant Characterization Unit, an advanced, gas-tight hydroponic research facility offering controlled environment and continuous monitoring of atmospheric gas composition. To evaluate biological and system effects of nutrient solution NH4 +:NO3 - ratio, two crop tests were run with different NH4 + to total N ratio (NH4 +:N) and elevated concentrations of Na+ and Cl- in line with a urine recycling scenario. Plants cultivated at 0.5 mol·mol-1 NH4 +:N (HiNH4 +) achieved 50% lower shoot biomass compared to those cultivated at 0.1 mol·mol-1 NH4 +:N (LoNH4 +), accompanied by higher shoot dry weight content and lower harvest index. Analyses of projected leaf area over time indicated that the reduced biomass observed at harvest could be attributed to a lower specific growth rate during the close-to-exponential growth phase. The HiNH4 + crop produced 40% less O2 over the full cultivation period. However, normalization of the results indicated a marginal increase in O2 production per time and per projected leaf area for the HiNH4 + crop during the exponential growth phase, in line with a higher shoot chlorophyll content. Mineral analysis demonstrated that the biomass content of NH4 + and NO3 - varied in line with the nutrient solution composition. The ratio of consumed NH4 + to consumed N was higher than the NH4 +:N ratio of the nutrient solution for both crop tests, resulting in decreasing NH4 +:N ratios in the nutrient solution over time. The results provide enhanced insight for design of waste processes and crop cultivation to optimize overall BLSS efficiency and hold valuable potential for improved resource utilization also in terrestrial food production systems.

Development of Nutrient Solution Compositions for Paprika Cultivation in a Closed Coir Substrate Hydroponic System in Republic of Korea’s Winter Cropping Season

Other than in highland areas, the majority of paprika growers in Republic of Korea transplant during late summer and cultivate when temperatures are relatively low. Additionally, they typically apply European nutrient solutions and hydroponic technologies with different climates and cultivation periods. Therefore, this study was conducted to determine the optimal nutrient solution composition based on growth stages suitable for paprika (Capsicum annum L.) cultivation in closed hydroponic systems with a coir substrate during the winter cropping season. The nutrient solutions were supplied to all the paprika plants at pH 5.8–6.0 and electrical conductivity (EC) 2.0–3.5 dS·m−1 according to the target EC setting for each growth stage. The mixing ratio of the reused nutrient solution (drainage) to the fresh solution was maintained within 30% on an EC basis (0.6–1.1 dS∙m−1) at each irrigation event. Paprika plants ‘Cupra’ were grown in three different nutrient solutions using an automated fertilizer dosing system based on integrated solar radiation (ISR). Nutrient absorption patterns according to growth stages were investigated for each nutrient solution. To reduce the nutritional imbalances of major nutrients in the root zone (RZ, substrate), the nutrient solution ‘NIHHS (National Institute of Horticultural and Herbal Sciences)’ was adjusted considering the nutrition absorption patterns according to growth stages, ion balances between anions and cations, and differences between the ion concentrations in the RZ and with irrigation. NIHHS-Coir1 and NIHHS-Coir2 solutions with 5–10% and 10–15% readjustments of macronutrient concentrations in the NIHHS, respectively, were used to evaluate the suitabilities for cultivation and productivity, whilst the IKC (Informatie en Kennis Centrum) nutrient solution was used as the control. We investigated the influence of these solutions on growth, yield, and photosynthetic responses compared to the conventional nutrient solution. Throughout the entire cultivation period, the newly formulated NIHHS-Coir1 solution had a marketable fruit ratio (%) of 2.4–3.5% higher and a marketable yield (kg/m2) of 5.3–8.7% higher than those of the conventional IKC solution.

Iron biofortification of broccoli microgreens under different radiation spectrum and composition of nutrient solution

Iron biofortification of broccoli microgreens under different radiation spectrum and composition of nutrient solution

Nutrient release coefficient: a proposed batch reactor assay to determine the elemental composition of aquaponic nutrient solutions

Nutrient release coefficient: a proposed batch reactor assay to determine the elemental composition of aquaponic nutrient solutions

Effect of Nutrient Solution Composition on Bio-Cemented Sand

Microbial-induced carbonate precipitation is an environmentally friendly foundation treatment technology that effectively improves soil engineering performance. The various nutrient components of liquid curing compounds significantly influence the curing effect. On the basis of penetration, dry density, water absorption, and unconfined compressive strength tests, this study showed the effect of nutrient solution composition, including urea, calcium chloride, sodium bicarbonate, ammonium chloride, and nutrient broth, on the physicomechanical properties of bio-cemented sand. The morphological differences of calcium carbonate precipitates under nutrient solution composition were compared through scanning electron microscopy (SEM). Results showed that the curing effect of compound nutrient solution was improved compared with the basic nutrient solution (urea and calcium chloride). Among the individual components added, ammonium chloride had the most remarkable effect, followed by sodium bicarbonate and nutrient broth. Among the paired components added, sodium bicarbonate + ammonium chloride had the most significant effect, followed by sodium bicarbonate + nutrient broth and ammonium chloride + nutrient broth. The strength of bio-cemented sand cured with compound nutrient solution containing five components could reach 3.43 MPa, which was 1.92 times higher than the strength of the basic nutrient solution. As shown by the SEM image, the calcium carbonate precipitation in the solidified sand was distributed in the clearance of sand particles, effectively bonding the sand particles. The calcium carbonate obtained by the composition of the compound nutrient solution precipitated the sand particles, and some of the sand particles were wrapped. Moreover, the amount of precipitation was evidently greater than that of the basic nutrient solution. Compared with the basic nutrient solution, the compound nutrient solution effectively reduced the apparent porosity and average pore size of the sand. Thus, the curing effect of the compound nutrient solution was better than that of the basic nutrient solution.

Scalable Architecture and Structure of Modules for Distributed Process Control System in Industrial Greenhouse Comp

With the growth of the population, the issue of food supply of cities with high-quality agricultural crops becomes urgent. Supply problems arising from this can be solved with the use of industrial greenhouse complexes with artificial lighting and groundless technologies. The development of these complexes makes the task of developing a control system to automate the cultivation processes urgent. Real industrial greenhouse complexes have a significant number of operations with the direct participation of personnel, which can be automated: control of the greenhouse microclimate, lighting, watering and preparation of the nutrient solution composition. This paper presents the architecture of a distributed control system for industrial greenhouse complexes. The system is built on a modular basis and is divided into three levels. The developed architecture is based on the use of standard modules, which makes the control system flexible and scalable. The paper also presents the basic design ratios, with the help of which it is possible to determine the required number of modules for the three levels of the proposed architecture. The use of wireless data transmission between modules based on LoRa technology allows you to abandon the laying of an information bus and at the same time deploy the system over large areas. Control of the system and its parameters is possible through direct human interaction with the interface of the control module or through remote interaction through the cloud. The architecture includes 3 types of executive modules, one combined sensor module and a control module. Each of the executive modules functions according to a given algorithm, and its parameters are controlled by a control module, based on a given growing program and information from sensors. This feature allows you to increase the reliability of the system and continue working in the event of a loss of communication with the cloud, as well as to exclude emergencies in the event of a loss of communication between the modules. The developed solutions make it possible to adapt the proposed control system for greenhouse complexes of various configurations and growing principles.

Impact of different nutrient solution composition on stinging nettle growth and mineral content

Impact of different nutrient solution composition on stinging nettle growth and mineral content

Appropriate NH4 +/NO3 - Ratio Triggers Plant Growth and Nutrient Uptake of Flowering Chinese Cabbage by Optimizing the pH Value of Nutrient Solution.

Compared with sole nitrogen (N), the nutrition mixture of ammonium (NH4+) and nitrate (NO3–) is known to better improve crop yield and quality. However, the mechanism underlying this improvement remains unclear. In the present study, we analyzed the changes in nutrient solution composition, content of different N forms in plant tissues and exudates, and expression of plasma membrane (PM) H+-ATPase genes (HAs) under different NH4+/NO3– ratios (0/100, 10/90, 25/75, 50/50 as control, T1, T2, and T3) in flowering Chinese cabbage. We observed that compared with the control, T1 and T2 increased the economical yield of flowering Chinese cabbage by 1.26- and 1.54-fold, respectively, whereas T3 significantly reduced plant yield. Compared with the control, T1–T3 significantly reduced the NO3– content and increased the NH4+, amino acid, and soluble protein contents of flowering Chinese cabbage to varying extents. T2 significantly increased the N use efficiency (NUE), whereas T3 significantly decreased it to only being 70.25% of that of the control. Owing to the difference in N absorption and utilization among seedlings, the pH value of the nutrient solution differed under different NH4+/NO3– ratios. At harvest, the pH value of T2 was 5.8; in the control and T1, it was approximately 8.0, and in T3 it was only 3.6. We speculated that appropriate NH4+/NO3– ratios may improve N absorption and assimilation and thus promote the growth of flowering Chinese cabbage, owing to the suitable pH value. On the contrary, addition of excessive NH4+ may induce rhizosphere acidification and ammonia toxicity, causing plant growth inhibition. We further analyzed the transcription of PM H+-ATPase genes (HAs). HA1 and HA7 transcription in roots was significantly down-regulated by the addition of the mixture of NH4+ and NO3–, whereas the transcription of HA2, HA9 in roots and HA7, HA8, and HA10 in leaves was sharply up-regulated by the addition of the mixture; the transcription of HA3 was mainly enhanced by the highest ratio of NH4+/NO3–. Our results provide valuable information about the effects of treatments with different NH4+/NO3– ratios on plant growth and N uptake and utilization.

Разработка технологии выращивания риса сортов «Айкерим», «Фаворит» и «Янтарь» методом гидропоники

One of the most important directions in rice farming is highly efficient resource-saving technologies. They are not only partially reduce the environmental burden on the environment throughout the country, but also very profitable from a financial point of view for the agricultural enterprises themselves. Rice cultivation on a hydroponic plant as a method of "green technologies" solves a number of environmental problems related to rice cultivation and the quality of rice itself. технологии выращивания риса сортов «Айкерим», «Фаворит» и «Янтарь» методом гидропоники The article examines the possibility of using the hydroponics method in the cultivation of rice varieties «Aikerim», «Favorite» and «Yantar». Nutrient solutions on the basis of Flora series universal complex, Uniflor complex with trace elements, and Aquarin water-soluble fertilizer compound were selected during the experiments of 3 rice varieties vegetation. The authors propose the most appropriate composition of nutrient solution for growing these rice varieties hydroponically. The article presents biometric characteristics of rice varieties grown on hydroponics, and also offers its own scheme of a hand-assembled hydroponic installation. It was found that under the conditions of lighting, temperature, and humidity specified in the experiment, the solutions of the Flora Series and created on the basis of water-soluble mineral fertilizers and the Uniflor complex are insufficiently favorable for rice cultivation. Whereas a nutrient solution based on mineral fertilizers (potassium ammonium nitrate, calcium nitrate, ammonium nitrate, magnesium sulfate, gelate) and complex give good results. Plants are obtained with full vegetation until full-grain maturity.

Modelling nitrogen, phosphorus, potassium, calcium and magnesium uptake, and uptake concentration, of greenhouse tomato with the VegSyst model

The existing version of the VegSyst model (V2) simulates daily dry matter production (DMP), crop evapotranspiration (ETc) and crop N uptake of tomato and other vegetable crops grown in greenhouse in SE Spain. In this study with greenhouse tomato, (i) the VegSyst model was adapted to simulate daily values of seasonal (i.e. throughout the crop) uptake of K, P, Ca and Mg, (ii) the simulation of seasonal N, K, P, Ca and Mg uptake was validated, and (iii) the simulation of seasonal uptake concentration (UC) of N, K, P, Ca and Mg was validated. For K, P, Ca and Mg, dilution curves (i.e. relationship of crop content of the nutrient (%) to DMP) were obtained from pooled data of six treatments from two greenhouse tomato crops. These relationships were all described by power equations with R2 values of 0.72–0.92 for all nutrients, except Mg that had a R2 of 0.40. For the simulation of tomato crop N uptake, the dilution curve previously used in V2 was replaced by the critical N curve for tomato of Padilla et al. (2015). The simulation of uptake of N, K, P, Ca and Mg was validated with a spring, soil-grown, long-life type, tomato crop (Tomato-11) and two long season soilless cherry tomato crops (Cherry-16 and Cherry-17). Seasonal uptake of N, K, P and Ca was adequately simulated in the three validation crops, with best performance (Relative Error (RE) ≤0.2) in the Cherry-17 crop. In the three validation crops, modelling of Mg uptake had poor performance. For simulation of UC in the two cherry tomato crops, there was good performance for N, K, P and Ca in Cherry-17, and reasonable to good performance in Cherry-16. The simulation of the UC for Mg was poor. The revised VegSyst model, identified as V3, will be incorporated into a decision support system (DSS) to provide recommendations for nutrient solution composition for soil-grown and soilless tomato crops grown in greenhouses.

Pengaruh Penambahan Ca(NO3)2 Terhadap Hasil Tanaman Selada Kriting (Lactuca Sativa L.) pada Sistem Hidroponik Deep Flow Technique (DFT)

The Effect of Addition of Ca(NO3)2 to the Results of Lettuce (Lactuca sativa L.) in the Hydroponic System of Deep Flow Technique (DFT). Plants, in general, require composition, concentration, and volume of nutrient solutions which different depends on the type and phase of plant growth. Leaf vegetable crops such as lettuce (Lactuca sativa L.) require higher Nitrogen (N) nutrients than other vegetable crops, but the problem we faced at the moment is the hydroponic nutrients that are traded only in the general form of nutrient, therefore the addition of N nutrients in the form of calcium nitrate (Ca(NO3)2) needs to be done to meet the needs of lettuce plants. This study was aimed to determine the effect of the addition of Ca(NO3)2 and to find the optimum dosage of the addition of Ca(NO3)2 to the general hydroponic nutrition of vegetables on lettuce use DFT hydroponic system. The treatments consisted of five levels which are nutrition AB Mix general vegetable as a control, and nutrition AB Mix with the addition of 30 g, 60 g, 90 g, and 120 g Ca(NO3)2. The results of the observation showed that the treatment of the addition of Ca(NO3)2 fertilizer had a very significant effect on all observed variables, except for the diameter of the lettuce plant. The optimum addition of Ca(NO3)2 for lettuce was found at 90.04 g with a maximum yield of 207.92 g.

Boron Biofortification of Portulaca oleracea L. through Soilless Cultivation for a New Tailored Crop

Purslane (Portulaca oleracea L.) is a wild edible plant, traditionally consumed in the Mediterranean area and recently proposed as a new ready-to-eat vegetable; it is also called the “vegetable for long life” because of the high contents of several healthy compounds. Although boron (B) is not considered to be essential for humans, a daily intake of about 2 mg to obtain positive effects on aging in adult men and women has been suggested. In this study, two genotypes of purslane (wild collected and commercial variety) are grown by using a hydroponic system with three boron (B) levels in the nutrient solution (NS) (0.3 mg/L—control, 3 mg/L—low level of biofortification, and 6 mg/L—high level of biofortification) in order to increase the B content in the edible parts of the plant. The crop yield, color traits, and content of glucose, fructose, total phenols, chlorophylls, carotenoids, mineral elements (Al, B, Ca, Cr, Fe, K, Mg, Mn, Na, and Zn), nitrate, and oxalate are analyzed. Independent of the genotype, the B content in edible purslane was successfully increased in comparison with the control, obtaining 1.8- to 10.7-fold higher values of B tissue concentrations by using, respectively, 3 and 6 mg/L of B in the NS without affecting crop performances. From a nutritional point of view, the average daily intake of B could be satisfied by consuming about 75 or 48 g of purslane, grown by using 3 and 6 mg/L B level in the NS, respectively. Apart from B and Fe, the content of mineral elements in edible parts of purslane was not strongly influenced by different B levels in the NS but it was affected by genotypes. A lower sugar content was found in wild purslane grown with the highest B level. A higher content of both chlorophylls and carotenoids was found in the control but only for the commercial genotype. No differences in oxalate content were observed among B levels in the NS, while only in the case of wild genotype, we found a lower nitrate content when a B concentration of 3 mg/L was used in the NS. In conclusion, we demonstrated the possibility of using the floating hydroponic system, combined with specific B concentrations in the NS composition, as a method to calibrate the B uptake in edible parts of purslane.

Nitrogen uptake competition between minute duckweed (LemnaperpusillaTorr) and microalgae under various nutrient composition

Implementation of minute duckweed (Lemnaperpusilla) in an integrated aquaculture system for encouraging movement of in-lake floating cage aquaculture to inland base aquaculture has been emphasized as one among various measures for restoring the degraded Lake Maninjau water quality. Unfortunately, in the field, there is a harmful competition between microalgae and duckweed for nutrient uptake. This paper reports an attempt to find out suitable nutrient solution composition for supporting duckweed growth while suppressing the microalgal proliferations. Batch culture of the plant with six varied media treatments (A to L) whichmade from Nitrogen-Phosphorus-Potassium (NPK) fertilizers basis enriched with trace elements, bio-algaecide (Terminalia Cattapa extract), and molasses solutions were examined. The adsorption of TN by duckweed and the assemblage of natural microalgae community was quantified and modelled using mass balance concept approach and non-linear equations. The result showed that among of 12 obtained models, treatment E (a solution which made from NPK fertilizer enriched with molasses and trace element) was the most favourable media composition for promoting duckweed growth and simultaneously suppressed microalgae growth. It is proven from the fact that the TN uptake patterns and the chlorophyll-a content which show chlorophyll-a content werethree magnitudes higher than those were found in treatment A (the most optimum medium for growing microalgae community). The TN uptake rate by minute duckweedin treatment of E was observed as much as 251.54 mg/m2/day while that ofmicroalgae was 208.60 mg/m2/day.

Nutrient solutions for Arabidopsis thaliana: a study on nutrient solution composition in hydroponics systems

BackgroundThere is little information on the effect of nutrient solutions composition on Arabidopsis growth. Therefore, we compared growth performance of Arabidopsis thaliana (Col-0) grown on the most commonly used nutrient solutions in deep water culture: Hoagland and Arnon, Murashige and Skoog, Tocquin, Hermans, and Conn. In addition to these nutrient solution composition experiments, we established Arabidopsis growth response curves for nutrient solution concentration and salt stress (NaCl).ResultsArabidopsis rosette fresh and dry weight showed an approximate linear decline with NaCl dose in deep water culture, i.e. 9% reduction relative to control per unit of electrical conductivity (EC in dS m−1, for scale comprehension 1 dS m−1 equals ~ 10 mM NaCl). The Tocquin, ½Hoagland and Conn nutrient solutions had equal and optimal growth performance. Optimal nutrient solution concentration for Tocquin and Hoagland was 0.8 to 0.9 dS m−1. Close to the EC of ½Hoagland (1.1 dS m−1), which is frequently used in Arabidopsis research. Conn solution showed optimal growth at much higher EC (2 dS m−1) indicating that it is a balanced nutrient solution that matches the needs of Arabidopsis. Full Murashige and Skoog solution (5.9 dS m−1) was lethal and diluted solutions (EC of 1.6 and 1.1 dS m−1) caused stress symptoms and severe growth retardation at later developmental stages.ConclusionsArabidopsis thaliana (Col-0) plants grown in deep water culture showed a sixfold growth difference when commonly used nutrient solutions were compared. Murashige and Skoog solution should not be used as nutrient solution in deep water culture. Conn, Tocquin and ½Hoagland are balanced nutrient solutions which result in optimal Arabidopsis growth in hydroponic systems.

Influence of ionic composition of nutrient solution on cultivation of perpetual varieties of strawberry in hydroponic columns

Influence of ionic composition of nutrient solution on cultivation of perpetual varieties of strawberry in hydroponic columns

Zinc and Iron Agronomic Biofortification of Brassicaceae Microgreens

Insufficient or suboptimal dietary intake of iron (Fe) and zinc (Zn) represent a latent health issue affecting a large proportion of the global population, particularly among young children and women living in poor regions at high risk of malnutrition. Agronomic crop biofortification, which consists of increasing the accumulation of target nutrients in edible plant tissues through fertilization or other eliciting factors, has been proposed as a short-term approach to develop functional staple crops and vegetables to address micronutrient deficiency. The aim of the presented study was to evaluate the potential for biofortification of Brassicaceae microgreens through Zn and Fe enrichment. The effect of nutrient solutions supplemented with zinc sulfate (Exp-1; 0, 5, 10, 20 mg L−1) and iron sulfate (Exp-2; 0, 10, 20, 40 mg L−1) was tested on the growth, yield, and mineral concentration of arugula, red cabbage, and red mustard microgreens. Zn and Fe accumulation in all three species increased according to a quadratic model. However, significant interactions were observed between Zn or Fe level and the species examined, suggesting that the response to Zn and Fe enrichment was genotype specific. The application of Zn at 5 and 10 mg L−1 resulted in an increase in Zn concentration compared to the untreated control ranging from 75% to 281%, while solutions enriched with Fe at 10 and 20 mg L−1 increased Fe shoot concentration from 64% in arugula up to 278% in red cabbage. In conclusion, the tested Brassicaceae species grown in soilless systems are good targets to produce high quality Zn and Fe biofortified microgreens through the simple manipulation of nutrient solution composition.

Influence of phosphorus and trace metals in biofilters treating gaseous VOCs using a novel irrigation system

ABSTRACT Although the appropriate supply of nutrients has been extensively researched, more information is required on the effects of nutrients in treating gaseous volatile organic compounds (VOCs) in biofiltration. In this study, the effects of phosphorous and trace metals on gaseous toluene and methyl ethyl ketone (MEK) removal were investigated. The transfer of nutrients from the irrigation liquid to the packed bed, and the consumption and holding amount of nutrients in the packing material were observed during biofiltration. Under conditions of 20–24 s of empty bed residence time, MEK removal was 95% or more in all conditions of the biofiltration reactors, whereas toluene removal was affected by the operating conditions of the reactors. Consumption ratio of phosphorus to carbon was from 1.7 × 10−4 to 1.1 × 10−3 in the steady state of VOC removal under the conditions of this study. When gaseous VOC treatment was restarted after nine days of shutdown, a significant decline in toluene removal was observed by the reactor in which phosphorus supply was approximately one fifth of the amount in another reactor. Two types of irrigation systems, soaking and spraying, were compared and soaking irrigation achieved a more even distribution of nutrients held inside the packed bed. Soaking irrigation was expected to lead to higher VOC removal capacity by this distribution effect of nutrients, but toluene removal in the reactor with this irrigation was lower than that in the reactor with spraying irrigation. One of the possible reasons for this was the inhibition of nutrients transfer in the bottom part of the reactor. The trend of transfer in all ingredients from the irrigation liquid to the packed bed was synchronized on the whole; however, this transfer relatively tended to be high in nitrate and sodium and low in ammonium and phosphate. Implications: A major concern about using biofiltration systems to treat VOCs is the uncertainty regarding the appropriate nutrient supply to the filter bed to preserve microbial activity. This study showed that all the elements, except nitrogen, were retained sufficiently in the filter bed when a proper composition of nutrient solution was used for irrigation; however, phosphate addition may be needed when restarting a reactor from a prolonged period of shutdown. Distinct differences in the amount of transfer to the filter bed for different ingredients are probable, and may have to be taken into account when operating biofiltration reactors.

Chemical composition and bioactive properties of Cichorium spinosum L. in relation to nitrate/ammonium nitrogen ratio.

Nitrogenous fertilizers may affect the yield and quality of leafy vegetables via the application rate and nitrogen form. In the present study, the effect of the nitrate:ammonium nitrogen ratio in the nutrient solution on the chemical composition and bioactive properties of Cichorium spinosum leaves was evaluated. For this purpose, C. spinosum plants were fertigated with nutrient solution containing different ratios of nitrate: ammonium nitrogen: (i) 100:0 NO3 -N:NH4 -N; (ii) 75:25 NO3 -N:NH4 -N; (iii) 50:50 NO3 -N:NH4 -N; (iv) 25:75 NO3 -N:NH4 -N; and (v) 0:100 NO3 -N:NH4 -N of total nitrogen; as well as (vi) 100% ureic nitrogen. The only detected tocopherol isoforms were α- and δ-tocopherol, which were positively affected by nitrate nitrogen (100:0 NO3 -N:NH4 -N). Similar results were observed for individual and total organic acids. The main detected sugars were fructose, glucose and sucrose, with a varied effect of nutrient solution composition on their content, whereas total sugar concentration was positively affected by a balanced or a slightly increased proportion of NH4 -N (50:50 and 25:75 NO3 -N:NH4 -N). The fatty acids profile was beneficially affected by the highest NH4 -N ratio (0:100 NO3 -N:NH4 -N), whereas higher amounts of NO3 - than NH4 + nitrogen (75:25 NO3 -N:NH4 -N) resulted in a higher content of total phenolic compounds. Finally, no cytotoxic effects were observed against non-tumor (PLP2, HeLa) and tumor (HepG2, MCF-7, NCI-H460) cell lines for any of the studied nutrient solutions. The modulation of NO3 -N:NH4 -N ratio in the nutrient solution supplied to C. spinosum may enhance the content of desirable health-promoting compounds and reduce the content of antinutrients, thus increasing the overall quality of the final product without compromising yield. © 2019 Society of Chemical Industry.

Optimasi Konsentrasi Larutan Hara pada Budidaya Selada (Lactuca Sativa l. var. grand rapid) dengan Teknologi Hidroponik Sistem Terapung

ABSTRACT The objective of this research was determined the optimum nutrient solution concentration on lettuce growth and yield in Deep Pool Growing System (THST). The study was conducted from November 2005 to March 2006 at Deep Pool Growing System facilities, Danasworo Hydrogarden Ciapus, Bogor (S 6 o 38’.19.78”, E 106 o 45’44.52”). The study was arranged in Completely Randomized Design with four levels of nutrient solution concentration. These are control (without nutrient), EC 0.75 mS.cm -1 , EC 1.50 mS.cm -1 and EC 2.25 mS.cm -1 . The composition of AB Mix nutrient solution were as followed (ppm): NH 4 + 22.5, K + 429, Ca 2+ 180, Mg 2+ 24, NO 3 - 1178, SO 4 2- 108, H 2 PO 4 - 194, Fe 3+ 2.232, Mn 3+ 0.275, Zn 2+ 0.261, B 3+ 0.324, Cu 2+ 0.049 dan Mo 2+ 0.048. Lettuce growth and yield was quadratically increased with nutrient solution concentrations application from 0 to 2.25 mS.cm -1 . Base on total plant weight and marketable plant weight, recommendation range of optimum nutrient solution concentration for lettuce hydroponic production in THST was between 1.09-1.15 mS.cm -1 .