Concentration In Nutrient Solution Research Articles

The role of nutrient solutions on Phosphate-solubilizing bacteria population, Phosphorus availability, Phosphorus uptake, growth and yield of Red Chili (Capsicum annuum L.)

Red chili consumption in Indonesia has increased every year. However, with large chili production to meet large consumption, land conversion for various purposes has reduced the harvested area. The efforts to increase the harvested area of chili using Inceptisols soil by providing nutrient solutions to overcome the infertility of the soil using its nutrients. This experiment aims to determine the effect of nutrient solution application on the population of phosphate-solubilizing bacteria, phosphorus availability, phosphorus uptake, growth, and yield of Red Chili (Capsicum annuum L.) in Inceptisols. The experiment was conducted from August 2023 to February 2024 at Ciparanje Experimental Field, Faculty of Agriculture, Padjadjaran University, and the analysis process was conducted at the Laboratory of Soil Biology and Soil Chemistry and Plant Nutrition, Department of Soil Science and Land Resources, Faculty of Agriculture, Universitas Padjadjaran., using a factorial randomized block design with two factors, nutrient solutions concentrates (1200, 1600, 2000 ppm) and nutrient solutions doses (200, 400, 600 mL), resulting in nine treatments and three replications. The results showed that the treatment of nutrient solution concentration and dose increased the number of fruits per plant, fruit weight per plant, and yield of chili with grade A. Treatment with 2000 ppm concentrate + 600 mL dose gave the best results on the number of fruits per plant (44.7 fruits), fruit weight per plant (725g), and grade A chili yield (73 fruits).

Selenium Improves the Nutritional and Antioxidant Properties of Oregano (Origanum vulgare L.) Grown in Hydroponics

Oregano (Origanum vulgare L.) is one of the most commercially popular aromatic spices which has long been used in folk medicine as a medicinal plant due to the presence of a wide group of bioactive secondary metabolites. The experimental data available to date indicate that plants of individual species within the Lamiaceae family implement different strategies for the absorption and distribution of selenium (Se) and differ in their metabolic response to Se treatment. In this regard, the present study investigated the effect of Se application (in the form of sodium selenate) at various concentrations (2.0, 5.0, 10.0, 20.0, and 40.0 μM) on the growth and accumulation of Se in oregano plant shoots and roots, as well as on nutritional components and secondary metabolites in shoots. The addition of Se to the nutrient solution at concentrations of 2–20 μM did not adversely affect the growth and accumulation of biomass in the oregano plants, which were characterized by a significant ability to transfer Se from roots to shoots (the translocation factor was >2). The Se treatment enhanced the nutritional proprieties of the oregano and, particularly, it stimulated the accumulation of carbohydrates and proteins (by 30 and 17%) and minerals (calcium and manganese). The total contents of phenolic compounds, flavonoids, hydroxycinnamic acids, luteolin-7-glucoside and its derivatives, catechin, 3,4-dihydroxybenzoic acid, rosmarinic acid and oleanolic and ursolic acids, as well as the percentage of essential oil, showed a dose-dependent increase in the oregano under the Se treatment. Changes in the relative content of the four main components of oregano essential oil (sabinene, germacrene D, β-caryophyllene, and (Z)-β-ocimene) under the Se treatment were not significant. The relative proportions of β-caryophyllene oxide and terpinen-4-ol increased with Se concentration augmentation in the nutrient solution. The obtained results indicate the prospect of using Se at 5–20 μM concentrations in nutrient solution in hydroponically grown oregano to produce Se-biofortified plants with higher levels of compounds beneficial to health and antioxidant activity without yield reduction.

Regulation of the physicochemical properties of nutrient solution in hydroponic system based on the CatBoost model

Too high or low nutrient solution concentrations adversely affect hydroponic vegetables’ growth and yield performance. In addition, the temperature of the solution and the dissolved oxygen (DO) content of the water are critical factors. A real-time regulation model for nutrient solutions based on the CatBoost model was developed to address the issues of low automation and accuracy of nutrient solution configuration and management. The pH, electric conductivity (EC) and DO of the nutrient solution, and the corresponding water temperature of 96 groups of hydroponic lettuce nutrient solutions (KNO3, MgSO4, Ca(NO3)2, KH2PO4, NH4H2PO4, and microfertilizer) were measured using a gradient combination test designed according to the formula of hydroponic lettuce nutrient solution. A prediction model of the nutrient solution index was constructed using a gradient-enhanced decision tree algorithm and the accuracies of the random forest, XGBoost, and CatBoost algorithms were compared. The results show that the root mean square error (RMSE), mean absolute error (MAE) and coefficient of determination (R2) of the simulated and measured values of the EC prediction model established by the CatBoost model were 248.28 µS/cm, 203.19 µS/cm and 0.946, respectively. At the same time, it was found that the hydroponic variable fertilization control system, composed of four modules–data acquisition, data decision, field control, and manual control–could predict the EC and pH value changes of the nutrient solution and timely add compounds for control. The application of nutrients based on the developed system was good and the weight of the cream lettuce (Flandria RZ) grown using the system was more than 200 g, which meets the requirement for high-quality cream lettuce production. Therefore, the CatBoost model system can be used to improve the hydroponic production system of vegetables by managing nutrients effectively.

Effects of Nitrogen Concentration in Nutrient Solution on Growth, Yield and Phytochemical and Aromatic Compounds of Persicaria minor Cultivated Using Hydroponics System

Persicaria minor, locally known as kesum and belonging to the family Polygonaceae, is a widely used aromatic herb in Malaysia. Cultivating kesum hydroponically using a deep-water culture (DWC) system presents an alternative method for growers to enhance crop yields. This system delivers a liquid fertilizer solution directly to the plant roots, eliminating the need for a growth medium or water flow. Kesum contains phytochemical compounds such as quercetin-3-glucuronide and quercitrin, which have medicinal properties. The primary objective of this study was to assess the effects of nitrogen concentration on the growth, yield, phytochemical (quercetin-3-glucuronide and quercitrin) and aromatic (aldehyde and caryophyllene) content of kesum cultivated in a hydroponic system. Plants were grown under four nitrogen concentration regimes: 200 mg/L, 100 mg/L, 50 mg/L, and 0 mg/L. The experiment was conducted under a side-netted rain shelter and arranged in a Randomized Complete Block Design (RCBD) with four replications. The plants were harvested eight weeks after planting. The result indicted those supplemented with 100 mg/L of nitrogen exhibited the best growth performance and biomass yield, along with the highest levels of aromatic compounds (aldehyde C-10: 5.80% and aldehyde C-12: 12.23%). Plants treated with 50 mg/L of nitrogen produced the highest amounts of quercetin-3-glucuronide (98.261 µg/mL) and quercitrin (61.367 µg/mL) compared to other treatments. Additionally, plants receiving 200 mg/L of nitrogen had the highest caryophyllene content (12.53%). In conclusion, the deep-water culture system in hydroponics can effectively cultivate kesum, allowing for adjustments in nitrogen concentration to achieve optimal yields, phytochemical levels, or aromatic compound production based on specific objectives.

Bottom-up effects of nutrient solutions on grape-grape phylloxera (Daktulosphaira vitifoliae) interaction.

Fertilizers generally influence the nutritional quality or defense ability of the plants, which can indirectly cause an increase in populations of herbivorous insect pests such as grape phylloxera, Daktulosphaira vitifoliae (Homoptera: Phylloxeridae, Fitch). The effects of nutrient solutions on grape-grape phylloxera interactions were analyzed using five concentrations (nitrogen content: 15, 30, 60, 120, and 180mg/L) of Hoagland's nutrient solution to irrigate Vitis vinifera L. × Vitis labrusca L. (Kyoho). Life table variables and life history variables showed a hump-shaped or an inverted hump-shaped curve as nutrient input level increased. Sixty microgram per liter treatment resulted in the greatest longevity and egg incubation, shortened the nymph duration and significantly increased the adult lifespan. Overall, both excessive and insufficient nutrient inputs curbed growth and multiplication of D. vitifoliae. These results provide a theoretical basis for vineyards for amending fertilizer inputs to prioritize the prevention and control of this pest.

Effects of different LED light spectra and nutrient solution strength on the growth, photosynthetic parameters, and nutrients uptake in tomato seedlings

Light-emitting diode (LED) lighting is currently the most energy-efficient lighting technology, and its use in agriculture is rapidly increasing. This research aimed to investigate the interaction effect of nutrient solution concentration and light quality on tomato seedlings growth. The tested factors included two nutrient solution concentrations (50% and 33% Hoagland solution) and four ratios of blue (440 nm) to red (660 nm) light in LED lighting at a constant light intensity (B2R1, B1R1, B1R2, and B1R3). Height growth was greatest in the 33% nutrient solution × B1R2 light treatment and smallest in the 33% nutrient solution × B2R1 light treatment. Regardless of the nutrient solution concentration, total chlorophyll and carotenoid concentrations decreased with an increase in the proportion of blue light. Plant absorption of sulfur was highest in the 50% nutrient solution × B1R2 light treatment, significantly higher than all other treatments. Although the 50% nutrient solution × B1R2 light treatment also showed the greatest magnesium absorption, it did not differ significantly from most of the other treatments. In general, for growing tomato seedlings, a high ratio of blue light regime (B2R1) with a dilute nutrient solution, enriched with magnesium and sulfur, can be recommended to prevent elongation disorder and have no negative impact on various growth and physiological indicators.

Response of Hydroponic Tomato Yield and Yield-correlated Morphological Characteristics to Constant or Growth Stage-based Nutrient Management Strategies

In the United States, the annual revenue attributable to tomato production is $1 billion. However, tomato production can cause negative environmental impacts, such as water pollution, often in the form of eutrophication-causing nutrient pollution. Hydroponic production can decrease excess nutrient leaching; however, optimization of nutrient management and cultivar choices could further decrease excess nutrient discharges. The objectives of this study were as follows: to evaluate and compare the responses of tomato growth characteristics, yield, and yield components to two nutrient management regimes (varying nutrient solution concentrations by growth stage and the use of a constant nutrient solution concentration from transplant to termination), and to analyze the effects of growth habits among six cultivars (Big Beef, Cherokee Purple, Heatmaster, Legend, Mountain Fresh Plus, and Tropic) on tomato yield and yield-correlated morphological characteristics. The nutrient management strategies were applied to tomato plants, and data regarding yield and related morphological characteristics were obtained. Data were analyzed using SAS PROC GLM. An analysis revealed no significant difference in the total fruit weight/plant between nutrient management regimes (P = 0.05); however, the mean fruit weight (164.26 g) and diameter (71.70 mm) were significantly greater (P < 0.0001) for plants that received the constant concentration nutrient regime. Indeterminate plants had a significantly greater (P < 0.0001) mean fruit weight (192.76 g) and mean fruit diameter (76.42 mm). Among cultivars, Big Beef had a significantly greater (P < 0.05) total fruit weight/plant (9.25 kg). Applying a constant nutrient concentration to indeterminate cultivars, particularly Big Beef and Cherokee Purple, improved the factors analyzed and could decrease negative environmental impacts while increasing profits of the producers.

Influence of Combined Supplemental Lighting and Nutrient Solution Concentration on Fruit Production and Quality of Cherry Tomato

We conducted an analysis on the combined effects of two light conditions (L1: greenhouse natural lighting; L2: greenhouse natural lighting plus supplemental lighting (SL)) and three nutrient solution concentrations (EC, NS1: 3.2 dS/m; NS2: 3.7 dS/m; NS3: 4.2 dS/m) on the growth, fruit production, and quality of two cherry tomato cultivars with different fruit coloring (‘Baiyu’ and ‘Qianxi’). The plants subjected to NS2 exhibited enhanced growth, photosynthetic parameters, and fruit production. The utilization of SL further enhanced stem diameter, leaf number, and single fruit weight, resulting in higher fruit weight per plant in ‘Baiyu’, which was not observed in ‘Qianxi’. The growth, fruit size, and fruit weight of both cultivars cultivated under NS3 conditions were suppressed, while these fruits exhibited elevated levels of total soluble solids (TSS), soluble sugars, vitamin C, polyphenols, fructose, glucose, sucrose, citric acid, and carotenoids. These levels were further enhanced by SL treatment. The improvement of fruit quality through the application of SL was found to be cultivar and EC dependent. In ‘Baiyu’, SL at NS1 significantly enhanced the accumulation of fruit water, minerals (N, P, K, Ca, and Mg), TSS, vitamin C, fructose, sucrose, and carotenoids. However, this effect was not observed in ‘Qianxi’. The combination of SL and EC 4.2 dS/m (NS3) generally contributes to the enhancement of fruit quality, while SL and EC 3.7 dS/m can ensure consistent fruit production. The yellowish-white fruit cultivar exhibited higher levels of soluble sugars, vitamin C, and polyphenols under L2NS3 conditions compared to the red fruit cultivar, whereas the carotenoid content showed an opposite trend. The findings are anticipated to establish a theoretical foundation for the consistent annual cultivation of cherry tomatoes in protected horticultural settings.

Fibrous anion exchanger with ternary amino groups as a component of the substrate for plants growing

A set of studies necessary to determine the suitability of a fibrous anion exchanger with ternary amino groups based on industrial polyacrylonitrile fiber Nitron C as a component of ion substrates was carried out. A laboratory-prepared ion exchanger sample had a working exchange capacity equal to 0.9 meq/g for the nitrate anion, which limits the biological productivity of the substrate for growing plants, in the physiological pH range = 5.5–7.5 and the concentration of the equilibrium nutrient solution is 0.02 eq/l. This capacity is at the level of the best granular ion exchangers and significantly exceeds the capacity of the previously used fibrous ion exchangers for growing plants in zero gravity conditions on space stations in 1970–1994 (Mir, Soyuz TM-10 – TM-17). The synthesized ion exchanger is a polyampholyte and contains three types of ion exchange groups, has high hydrophilicity and mechanical properties that allow it to be processed into textiles and used for any purpose, in which fibrous ion exchangers can be used (air and water purification, human protection means, etc.).

SEED POTATO PRODUCTIVITY AS INFLUENCED BY ELECTRICAL CONDUCTIVITY OF THE NUTRIENT SOLUTION IN SOILLESS MEDIA DURING SPRING SEASON IN SUBTROPICAL REGIONS OF N- W INDIA

Soilless cultivation under controlled conditions is used for rapid multiplication of early generation virus-free potato seed using aeroponics and other mediums. The plant growth under these systems is affected by different factors like soilless media, nutrient solution concentration used, environment, genotype etc. Besides the composition of nutrient solution its electrical conductivity (EC) influences availability of nutrients and affects plant growth and yield. The two-factorial study on water source and EC was carried out on a cocopeat based medium for a nutrient efficient variety Kufri Gaurav. Well sprouted aeroponically produced minitubers of the variety were planted (at 30 x 15 cm planting density) in soilless medium filled troughs placed under net house. The water source Normal tap water was compared with RO (demineralized) water, while EC was considered at three levels 1.0, 1.5 and 2.0. The results indicated a proficient growth of the genotype at EC 2.0 (plant height, number of leaves, stem diameter, leaf length and number of stems). However, for the yield characters, EC 1.0 was found to produce both higher number of tubers, yield as well as harvest index per meter square. Based on the observations it can be inferred that at lower EC the partitioning of the photosynthates is towards the sink (tubers) as compared to the vegetative growth, which would be more desirable under the soilless systems, where limited/ managed canopy growth is more desirable, with higher productivity. The study also indicated virus free seed production in soilless medium during the spring season (seed plot period lasts up to December) in northwestern plains of India under net house, giving indication for successive/ multiple seed crops under soilless controlled conditions.

Effects of LED treatments on the growth and nutritional content of lettuce (Lactuca sativa) in a hydroponic vertical farming system

Introduction: LED-integrated hydroponic vertical farming system (HVFS) may address food security challenges arising from urbanisation, while antioxidants in vegetables may prevent cardiovascular disease. This study aimed to explore the LED effects on yield, antioxidant properties, and vitamin C content in Butterhead lettuce (BL) and Italian lettuce (IL). Methods: Three LED combinations were used: 77% red, 14% green, and 9% blue lights (77R:14G:9B); 7% red, 41% green, and 52% blue lights (7R:41G:52B); and 25% red, 67% green, and 8% blue lights (25R:67G:8B). The concentration and pH of nutrient solution in HVFS ranged from 0.878-2.061ppm and 6.0-6.6, respectively, with a 12:12 light-dark cycle. Chlorophyll and anthocyanin contents were measured using chlorophyll and anthocyanin meters, respectively. Total phenolic and vitamin C content were measured using Folin-Ciocalteu colorimetric assay. Total flavonoid and antioxidant activity were determined through aluminium chloride colorimetric assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) colorimetric assay, respectively. Completely randomised design was adapted with three replications. Results: BL exhibited greater yield, anthocyanin and chlorophyll contents, while IL had higher vitamin C content. Significantly (p<0.001) higher yields were produced under 77R:14G:9B and 25R:67G:8B. Significantly higher phenolic (p<0.001) and flavonoid (p=0.003) contents were produced under 25R:67G:8B. Vitamin C was significantly (p=0.037) higher under 25R:67G:8B than 7R:41G:52B. Conclusion: LED treatment with higher proportion of red light generated greater yield, whereas higher proportion of green light gave higher phenolic, flavonoids, and vitamin C accumulation. This study provided preliminary data on boosting crop yield and phytochemical contents, which may improve food self-production and population health.

Effect of Substrates and Nutrient Solution Concentrations on Growth and Yield of Cardamom (Amomum testaceum Ridl.) in Soilless Culture

This research aimed to investigate the effects of the substrates and nutrient solutions on the growth and yield of cardamom in soilless culture. The experimental design was 2x3 Factorial in Completely Randomized Design with 5 replications. First factor consisted of coconut coir dust and coconut husk chips and the second factors were 3 nutrient solution concentrations; EC=1.00, 2.00 and 3.00 mS/cm. The experiment was carried out during July to December, 2021. The results showed that cardamom grown using coconut husk chips with nutrient solution concentration of EC= 3.00 mS/cm yielded the highest plant weight (256.00 g/plant) and the highest number of plants (21.30 plant/pot), respectively. For the analysis of interaction effect between substrates and nutrient solution concentrations, it was found that cardamom grown by using chopped coconut husks at EC 3.00 mS/cm gave the highest number of plants (23.60 plants/pot). Therefore, to produce shoots for sale, cardamom should be planted using coconut husk chips at EC 3.00 mS/cm in order to obtain the best cardamom growth and yield.

Cultivo de alface em diferentes sistemas hidropônicos e concentrações de nutrientes na solução nutritiva

ABSTRACT Alternative techniques for cultivation without soil are widespread; however, studies comparing hydroponic systems still need to be studied, mainly in semi-arid regions. The present study aimed to evaluate the effect of hydroponic systems on the yield and quality of lettuce cultivars subjected to different electrical conductivities of the nutrient solution. The research was conducted in a greenhouse, adopting a completely randomized design in a 2 × 2 × 3 factorial scheme, being two lettuce cultivars (Cinderela and Rubinela), two electrical conductivities (2.90 and 1.6 dS m-1), and three hydroponics systems (NFT, semi-hydroponic, and floating), with three replications. The number of leaves, leaf succulence, specific leaf area, leaf fresh mass, total dry mass, leaf area, titratable acidity, vitamin C, and soluble solids were evaluated. Cinderela cultivar showed the highest average leaf fresh mass, total dry mass, leaf area, and vitamin C values. The NFT and floating systems provided the highest leaf yield and quality, especially in the solution of 1.60 dS m-1. The semi-hydroponic system provided greater development of the plants with a more concentrated nutrient solution (2.90 dS m-1).

Suitable Water–Fertilizer Management and Ozone Synergy Can Enhance Substrate-Based Lettuce Yield and Water–Fertilizer Use Efficiency

As living standards rise, enhancing quality has become a central objective for many researchers. Soilless cultivation, known for its efficient use of resources, is increasingly used in vegetable production. It is critical to develop effective water and fertilizer management strategies to achieve high-quality yields and promote sustainable development in modern agriculture. This study employed an orthogonal experimental design to assess the impact of varying nutrient solution concentrations (50%, 75%, 100%, and 125% of Hoagland’s), lower irrigation thresholds (40%, 55%, 70%, and 85% field capacity (FC)), and ozone concentrations (0, 1, 2, and 4 mg·L−1) on lettuce growth, yield, quality, and water–fertilizer use efficiency. The results indicated that fixed nutrient solution concentrations and lower irrigation thresholds enhanced growth metrics for lettuce. Similarly, increasing ozone concentrations initially improved, then reduced growth metrics when the lower irrigation threshold was constant. Furthermore, maintaining stable ozone concentrations while raising the nutrient solution concentration initially boosted, then diminished, growth indicators. Optimal conditions for water and fertilizer management were identified at a nutrient solution concentration of 75% to 100% and an ozone concentration of 0 to 1 mg·L−1. Variance analysis highlighted the significant effects of nutrient solution concentration, lower irrigation thresholds, and ozone concentrations on lettuce yield, quality, and water and fertilizer use efficiency. Range analysis revealed the optimal management combination to be a nutrient solution concentration of 100%, an 85% lower FC irrigation threshold, and an ozone concentration of 1 mg·L−1, yielding 16.82 t·ha−1 of lettuce and a water use efficiency of 40.14 kg·m−3. These findings provide theoretical support for the sustainable advancement of soilless cultivation in contemporary agriculture.

Efficacy and selenium enrichment of Lycium barbarum in hydroponic and soil conditions in the Ararat valley

Background: It is known that 60-80% of the population affected by various diseases, such as heart attack, stroke, and oncological diseases is associated with selenium (Se) deficiency. Therefore, enriching agricultural crops with Se is considered a current issue. Objective: This study investigates Se enrichment of Lycium barbarum (Lb) and its effectiveness in hydroponic and soil conditions in the Ararat Valley. The research focuses on the impact of adding exogenous Se on plant productivity, Se accumulation, and the content of biologically active substances (BAS) in Lb berries and leaves. Methods: The experiments were conducted from 2021 to 2023 using hydroponic and soil cultivation methods with varying Se concentrations in nutrient solutions and foliar nutrition. Results: The results demonstrate that Se enrichment significantly increased Se and BAS levels in both leaves and berries of Lb, with hydroponic cultivation exhibiting higher accumulation compared to soil conditions. Foliar feeding with a 0.005% Se solution and exogenous Se addition to nutrient solutions at 1.0 mg/L resulted in notable improvements in Se content and plant productivity. Furthermore, the analyses revealed significant differences between hydroponically and soil-grown Lb, emphasizing the potential of hydroponic cultivation for producing Se-enriched plant material with enhanced BAS content. Conclusion: Hydroponic cultivation supplemented with Se and foliar nutrition is recommended for obtaining Se-rich Lb plant material, which is suitable for medicinal and functional food purposes. These findings contribute to the development of biotechnologies for Se -enriched plant production and addressing health and nutritional needs. Keywords: Goji, berries, biologically active substances, flavonoids, phenolic acids, tannins, carotenoids

Identification and selection of reference genes for analysis of gene expression by quantitative real-time PCR in the euhalophyte Suaeda altissima (L.) Pall.

ABSTRACT Сoding sequences of seven housekeeping genes: actin SaACT7, ubiquitin-conjugating protein SaUBC10, glyceraldehyde-3-phosphate dehydrogenase SaGAPDH, protein of the large subunit of ribosomes SaL2, α-tubulin SaTUA, translation elongation factor SaeEF1α, and protein phosphatase SaPP2A were identified as candidate reference genes for expression analysis of target genes in the extremely salt tolerant plant Suaeda altissima (L.) Pall. The expression profiles of the genes differed. SaACT7 and SaeEF1α demonstrated the highest expression levels, while the lowest expression levels were found for SaPP2A and SaTUA. SaPP2A and SaeEF1α genes were the most stably expressed at different steady-state salinity levels and different nitrate concentrations in nutrient solutions (NSs). SaL2, SaPP2A, and SaeEF1α genes showed the greatest stability of expression when nitrate was added to nutrient solution of plants grown under conditions of nitrate deficiency. Less constant expression was demonstrated in this experiment by SaACT7 and SaTUA. SaL2, SaACT7, SaeEF1α, and SaUBC10 genes showed the smallest expression changes under salt shock. To validate the use of the most stably expressed genes for normalization of gene expression, we checked them as reference genes to study the expression of the nitrate transporter gene SaNPF6.3 in S. altissima roots under conditions of different salinity and different nitrate supply.

Growth, gas exchange, and leaf anatomy of Echinodorus grandiflorus (Cham. & Schltr.) Micheli under Pb contamination.

Lead (Pb) can be deposited in aquatic environments that are especially subject to pollution due to wastewater and sewage disposal. This study aimed to evaluate the tolerance of Echinodorus grandiflorus (Cham. & Schltr.) Micheli to Pb and changes in growth, gas exchange, and leaf anatomy. Experiments were conducted with E. grandiflorus plants exposed to the following Pb concentrations in nutrient solution: [0; 0.75; 1.5; 3.0 and 9.0μM Pb (NO 3)2] in a greenhouse for 60days. At the end of the experiment, the lead concentration, growth, leaf gas exchange, and changes in leaf anatomy were evaluated. There was no mortality of E. grandiflorus plants, and they accumulated higher concentrations of Pb proportional to the concentration of the pollutant in the solution. Pb did not cause significant changes in growth, stomatal conductance, transpiration, and Ci/Ca rate but reduced the photosynthesis in E. grandiflorus. The leaf anatomy showed significant changes in the presence of Pb, reducing the epidermis and chlorophyll parenchyma. E. grandiflorus demonstrated tolerance to Pb, surviving and growing under contamination; however, it negatively modified its leaf anatomy and photosynthesis in the presence of the metal.

Growth Dynamics and Nutrient Removal from Biogas Slurry Using Water Hyacinth

Aquatic macrophytes, notably the invasive water hyacinth, exhibit proficiency in nutrient removal from polluted water bodies, rendering them appealing for water remediation applications. This study investigates the potential of water hyacinth in phytoremediation, focusing on the effect of using nutrient-rich biogas slurry mixed with water in varying concentrations, i.e., 16.6, 33, 66.6, 100, and 133 mg/L for the investigation. The physiochemical properties of the liquid biogas slurry were evaluated before and after treatment with water hyacinth over eight weeks, with continuous monitoring of nutrient reduction rates. Results showcased substantial average reductions of nitrogen, phosphorus, and potassium, with a relative growth rate of 5.55%. The treatment also decreased pH, total dissolved solids, hardness, and chemical oxygen demand. The theoretical BMP of water hyacinth was determined using Buswell’s equation. Water hyacinth grown in the concentration of the biogas slurry exhibited the highest methane yield at 199 mL CH4/gm VS, along with the highest relative growth rate. This study used experimental data to create a mathematical model that describes how the relative growth of water hyacinth depends on the number of days and biogas slurry concentration (C). The model’s quality and effectiveness were evaluated using the goodness of fit (R2) and observable approaches. The polynomial model, referred to as Poly model 1, 2, is the best fit for describing the relationship between the growth percentage of water hyacinth, days, and nutrient solution concentration. In this model, C has a polynomial degree of one (normalized mean of 69.84 ± 43.54), while D has a degree of two (normalized mean of 30 ± 21.65).

The responses of pepper plants to nitrogen form and dissolved oxygen concentration of nutrient solution in hydroponics

BackgroundThe presence of oxygen in the growth medium is absolutely essential for root development and the overall metabolic processes of plants. When plants do not have an adequate oxygen supply for respiration, they can experience a condition known as hypoxia. In order to investigate the impact of different nitrogen forms and varying oxygen levels in nutrient solutions on the growth, photosynthesis, and chlorophyll fluorescence parameters of bell pepper plants, a comprehensive study was conducted. The experiment was designed as a factorial experiment, considering two main factors: nitrogen forms (calcium nitrate and ammonium sulfate) with a fixed nitrogen concentration of 5 mM, and the oxygen levels of the nutrient solutions (ranging from 1.8 ± 0.2 to 5.3 ± 0.2 mg. L-1).ResultsThe study examined the effects of nitrogen (NH4+ and NO3−) application on various parameters of vegetative growth. The results demonstrated that the use of ammonium (NH4+) led to a reduction in the most measured parameters, including the fresh and dry mass of both the root and shoot, at low O2 concentrations of 1.8 ± 0.2; 2.6 ± 0.2 and 3.8 ± 0.2 mg. L-1. However, an interesting observation was made regarding the impact of oxygen levels on root growth in plants grown with nitrate (NO3−). Specifically, the highest levels of oxygen significantly increased root growth in NO3−-fed plants. Additionally, the application of NH4+ resulted in an increase in chlorophyll concentration in the leaves, particularly when combined with high oxygen levels in the nutrient solution. On the other hand, leaves of plants fed with NO3− exhibited higher photosynthetic rate (A), intrinsic water use efficiency (iWUE), and instantaneous carboxylation efficiency (A/Ci) compared to those fed with NH4+. Furthermore, it was found that NO3−-fed plants displayed the highest instantaneous carboxylation efficiency at oxygen levels of 3.8 and 5.3 mg. L-1, while the lowest efficiency was observed at oxygen levels of 1.8 and 2.6 mg. L-1. In contrast, NH4+-grown plants exhibited a higher maximal quantum yield of PSII photochemistry (Fv/Fm), as well as increased variable fluorescence (Fv) and maximum fluorescence (Fm), compared to NO3−-grown plants. Interestingly, the NO3−-fed plants showed an increase in Fv/Fm, Fv, and Fm with the elevation of oxygen concentration in the nutrient solution up to 5.3 mg. L-1.ConclusionThis study showed that, the growth and photosynthesis parameters in bell pepper plants are sensitive to oxygen stress in floating hydroponic culture. Therefore, the oxygen level in the nutrient solution must not be lower than 3.8 and 5.3 mg. L-1 in NH4+ and NO3− –supplied culture media or nutrient solutions, respectively.

Optimizing nutrient solution for vegetative growth of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan through plant tissue nutrient balance estimation

BackgroundOrchids are grown without soil in many regions of the world, but there is a lack of studies to define the balanced and adequate nutrient solution for their cultivation, mainly in the vegetative growth phase. Therefore, this paper aims to evaluate the optimal concentration of the nutrient solution based on the proposal by Hoagland and Arnon (1950) in the vegetative growth phase capable of increasing the nutrient contents, growth, and dry matter production of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan. In addition, this paper aims to estimate a new nutrient solution from the optimal nutrient contents in the dry matter of these orchid species to be used in the vegetative growth phase.ResultsNutrient contents, growth, and dry matter production increased as the nutrient solution concentration increased up to an average concentration of 62 and 77% for D. Tubtim Siam and P. Taisuco Swan, respectively. We found that the Hoagland and Arnon solution presented a group of nutrients with concentrations above the requirement for P. Taisuco Swan (nitrogen, phosphor, calcium, and sulfur) and D. Tubtim Siam (phosphor, calcium, magnesium, and sulfur), while other nutrients in the solution did not meet the nutritional demand of these orchid species, inducing nutritional imbalance in the vegetative growth phase.ConclusionWe conclude that using a balanced nutrient solution created specifically for each orchid species in vegetative growth might favor their sustainable cultivation by optimizing the use of nutrients in the growing medium.