Concentration In Nutrient Solution Research Articles

Sample Temperature Affects Measurement of Nitrate with a Rapid Analysis Ion Selective Electrode System Used for N Management of Vegetable Crops

The practical value of portable hand-held ion selective electrode sensors (ISE) for on-farm [NO3−] measurement to assist with crop N management of vegetable crops has been demonstrated in numerous previous studies. They provide rapid, in-situ measurement of the nitrate concentration ([NO3−]) in nutrient and soil solutions, and in petiole sap. Sample temperatures, for on-farm measurements, vary appreciably. This study evaluated the effects of sample temperature on [NO3−] measurement using two different models of a commonly used, commercially available, portable ISE meter. The temperatures (5, 10, 15, 20, and 25 °C) examined were in the range likely to be encountered in practical on-farm work. Aqueous solutions of 6, 12, and 18 mmol NO3− L−1 were prepared from KNO3, Ca(NO3)2 and NaNO3. [NO3−] was measured in three replicate samples of each of the three concentrations, made from each NO3− compound, at each temperature. The results consistently and clearly demonstrated a strong negative linear relationship between temperature-induced errors and sample temperatures. The temperature-induced error was considerable for cooled samples, being +50% at 5 °C and +31% at 10 °C. At sample temperatures of 17–20 °C, the temperature effects were minimal. Above this range, the temperature effect caused underestimation. At 25 °C, the temperature-induced error was −24%. These results show that care must be taken to ensure that sample temperatures do not erroneously affect the measurement of [NO3−] with ISE meters. Particular care needs to be taken with both refrigerated and warmer samples.

UTILIZATION OF ORGANIC LIQUID COFFE FERTILIZER (COFFEA ARABICA L.) AS HYDROPONIC NUTRITION IN MUSTARD PLANTS (BRASSICA JUNCEA L.)

As mustard greens contain various benefits that are beneficial to health, because the mustard greens contain vitamins and minerals that play an important role in the process of growth and metabolism of the body. One way to grow vegetables in a narrow area is to use a hydroponic system. Hydroponics is a way of farming without using soil media but uses water as a medium and uses nutrients as nutrients for plant growth. Hydroponic cultivation is one of the efforts to obtain quality agricultural products, healthy, and free of pesticides. However, the use of hydroponic nutrients for now is still sourced from chemical fertilizers. Therefore, one solution to reduce the use of inorganic fertilizers can be used organic fertilizers, namely liquid organic fertilizer which is more easily absorbed by plants because the elements in it have been decomposed. One of the wastes that can be used as liquid organic fertilizer is coffee grounds waste. This study aims to determine the use of liquid organic fertilizer coffee grounds (Coffea arabica L.) as hydroponic nutrients in mustard plants (Brassica juncea L.). This research was conducted from February to April 2020, located at the Integrated Research Laboratory and the wire house of the Department of Biology FMIPA UNP. This study uses a completely randomized design (RAL) with 5 treatments and 3 replications. Data were analyzed using the Analysis of Variance (ANOVA) and DNMRT follow-up tests at the 5% level. The results showed that various concentrations of hydroponic nutrient solution with liquid organic fertilizer based on coffee grounds had a significant effect on increasing the growth of mustard plants (Brassica juncea L.) both from plant height, number of leaves and leaf area. Keywords: Coffea Grounds, Hydroponics, Liquid Organic Fertilizer, Plant Sawi

Effect of sodium chloride on physiological, biochemical traits, and mineral nutrition inhibition of peanut varieties in large temperature fluctuations

Peanut has a high nutritional value which would be influenced by soil salinization that arises because of climate change. In this paper, the effects of salinity on morphological, physiological biochemical parameters and mineral absorption inhibition of the three varieties cultivated in Cameroon, namely ICGV86003 (V1), Metchicha (V2), and JL 24 (V3) were evaluated under large temperature fluctuations. Plants of each variety were grown at four concentrations of Wacquant's nutrient solution 0, 40, 80, and 120 mM of NaCl 20 days after germination under an unstable environment. The experiment pots were arranged in a completely randomized design with five replicates. The results showed that the three studied peanut varieties present distinct indicators for salt tolerance. Total Leaf Area (TLA), Fresh Weight (FW), and Relative Water Content (RWC) decreased from 80 mM, 40mM, and 80 mM of NaCl respectively. Bound water (BW) increased from 40 mM of NaCl in all varieties. Total sugars, total protein, and peroxidase content increased from 40 mM of NaCl, while polyphenol content increased from 40 mM NaCl in the V1 variety and 80 mM of NaCl in the V2 and V3 varieties. In addition, nutrient elements left in the soil were elevated from 40 mM of NaCl while N was reduced under the same salt conditions for V2, V3, and V1 respectively. These results suggest that the adaptive mechanism of the studied varieties of peanut to salt stress under temperature fluctuations reduces the uptake of mineral elements by the plant and is at the origin of the poor organoleptic quality of fruits.

The Evaluation for Salvinia sp. Adaptation to Iron Concentration on Nutrient Solution and Tidal Swamplands Soil Growing Media

Salvinia sp. is an alternative aquatic plant that is abundant in the swamplands and can be used for bioremediation of water contaminated with metals. The objectives of the experiment were (1) to evaluate the adaptation of Salvinia sp. to the iron (Fe) concentration in nutrient solution and tidal swampland soil growing medium and (2) to obtain Fe-adaptive Salvinia sp. as indicated by having rapid growth and high biomass. The experiment has been carried out in Cikabayan greenhouse IPB University, Bogor. Salvinia sp. was evaluated in a 4-liter plastic container with Hoagland nutrient solution that was supplemented with Fe based on the experimental treatments. The 10 accessions of Salvinia sp. were selected and evaluated using a pot filled with soil from tidal swampland. The results showed that increasing Fe concentration from 7 to 14 ppm in solution inhibited the growth, reduced the fresh weight, and delayed the doubling time of Salvinia sp. The selection of Salvinia sp. on 7 ppm Fe obtained 4 Salvinia sp. accessions with high biomass weights and fast doubling time, namely S. Kambat, Murung Karamat, Gambut, and Muning Tengah. Among the 4 accessions, the best two were S. Kambat and Murung Karamat with a fast doubling time of about 7.9 days and were adaptive in the tidal swampland.

Biofortification and Quality of Collard Greens as a Function of Iron Concentration in Nutrient Solution

The agronomic biofortification of vegetables is a strategy for increasing the concentration of iron (Fe) in food and, consequently, the intake of this micronutrient by the population. When in deficiency, it can cause anemia—a pathology that affects millions of people. Soil-less cultivation is an important cropping system, but there are no studies on how Fe concentrations in a nutrient solution can promote biofortification and affect the quality of collard greens; this is the aim of the present study. For this purpose, five Fe concentrations (2, 4, 6, 8 and 10 mg L−1) were evaluated. Increasing the Fe concentration in the nutrient solution increased the leaf Fe content and decreased the leaf contents of cationic nutrients, without affecting yield. Photosynthetic pigment contents were positively affected by Fe concentrations, while ascorbic acid decreased. There was efficient biofortification of collard greens leaves from 4 mg L−1 Fe, and a higher nutritional quality of leaves was observed at Fe concentrations of 8 mg L−1.

Sensory Evaluation of Common Ice Plant (Mesembryanthemum crystallinum L.) in Response to Sodium Chloride Concentration in Hydroponic Nutrient Solution.

Common ice plant (Mesembryanthemum crystallinum L.) is a novel edible plant with a succulent and savory flavor. The plants display prominent epidermal bladder cells (EBCs) on the surface of the leaves that store water and sodium chloride (NaCl). The plants have high nutritional value and are adapted to saline soils. Previous research has determined the impact of NaCl on the growth and mineral content of ice plant, but as NaCl has an impact on a food’s sensory properties, an interesting question is whether saline growth media can affect the plant’s taste and texture, and if this alters consumers’ sensory response to ice plant. The objective of this study was to evaluate the sensory aspects of ice plant, as well as consumer liking in response to increasing NaCl concentration in hydroponic nutrient solution. Four-week-old seedlings of ice plant were transplanted into deep water culture (DWC) hydroponic systems and treated with five NaCl concentrations (0 M [control], 0.05 M, 0.10 M, 0.20 M, and 0.40 M NaCl). Eight-week-old plants (after four weeks of NaCl treatment) were harvested, and the middle leaves of each plant were sampled for consumer testing. A total of 115 participants evaluated various flavor, texture, and appearance aspects of ice plant and provided their liking ratings. The consumers were able to discriminate differences in salt intensity from the plants based on NaCl treatment in the hydroponic nutrient solution. Low NaCl concentrations (0.05–0.10 M) did not have obvious adverse effect on consumer liking, which aligns with the result of previous research that 0.05–0.10 M NaCl could largely stimulate the growth of ice plant. NaCl concentrations higher than 0.20 M are not recommended from both a production and consumer perspective. With increased NaCl level in plant samples, the consumers detected more saltiness, sourness, and fishiness, less green flavor, and similar levels of bitterness and sweetness. NaCl treatment had no effects on leaf appearance and texture, and the consumers’ overall liking was mainly determined by flavor. Overall, ice plant presents some unique attributes (salty and juicy) compared to other edible salad greens; however, consumer awareness of ice plant is very low, and purchase intent is relatively low as well. Consumers picture ice plant being used mainly in salads and in restaurants.

Effect of moderate salinity on Golden Thistle (Scolymus hispanicus L.) grown in a soilless cropping system

• Soilless cultivation of S. hispanicus l. improved plant growth and yield characteristics. • S. hispanicus L. was resilient to moderate salinity until 90 days after transplant. • Salinity level of 10.0 and 15.0 mM improved functional quality characteristics. • Physiological indicators significantly declined at salinity levels of 10 and 15 mM NaCl. Selecting salt-tolerant crop species for cultivation might be a feasible option to maintain crop productivity in arable lands affected by salinity. In this context, here we examine the responses of the wild edible green golden thistle ( Scolymus hispanicus L.) to moderate levels of salinity when grown in a soilless system for culinary use. Treatments were obtained by establishing four NaCl concentrations (0.5, 5.0, 10.0, and 15.0 mM) in a standard nutrient solution, resulting in initial solution electrical conductivities (EC) of 2.2, 2.8, 3.2, and 3.8 dS m − 1 , respectively. By the end of the experiment, 120 days after transplanting (DAT) drainage EC reached 2.65, 3.33, 3.96, and 4.51 dS m − 1 , respectively. At the first harvest, 90 DAT, the increase of the NaCl concentration had no significant impact on the number of leaves per plant, leaf fresh and dry weight [g plant −1 ], and root dry weight [g plant −1 ]. At the second harvest (120 DAT), 15.0 mM NaCl significantly decreased root and leaf fresh and dry weight without affecting the number of leaves per plant compared to 0.5 and 5.0 mM NaCl, while 10 mM NaCl had no impact on any of these parameters. The concentrations of K + , Ca 2+ , Mg 2+ , and P in the leaves were not influenced by the tested salinity levels, while those of organic-N and NO 3 − -N were significantly reduced by 10 and 15 mM NaCl, 90 DAT. Furthermore, 10 and 15 mM NaCl significantly increased the Cl − and Na + concentrations in leaves, but not in the roots. In the root tissues, only the K concentration was reduced by salinity while P increased at the highest salinity level (15 mM NaCl). Based on these results, we conclude that S. hispanicus L. is resilient to moderate salinity levels and can be considered a promising candidate plant for introduction to soilless cropping systems.

Assessment of physicochemical characteristics of biofertilizers and their role in the rooting capacity of plants

The concentration of supplied mineral nutrients is one of the most important and limiting factors for enhancing the efficiency of plant nutrition. Optimal concentration of nutrient solutions (NS) provide plants with the necessary amount of nutrients. From this point of view, research on several physicochemical parameters that characterize concentrations of NS and uptake of nutrients by the plants remains an actual problem. The changes of electrical conductivity (EC) and total dissolved solids (TDS) depending on the concentration of biofertilizer as well as the role of biofertilizer solutions on the rooting capacity of cuttings (lateral sprouts) of Callisia fragrans are presented here. The EC and TDS of the biofertilizer-water mixture changed gradually according to the biofertilizer concentration. The biofertilizer solution was a good medium for the rooting of C. fragrans cuttings. The results could help to provide the crops with the necessary amount of mineral nutrients and regulate the suitability of irrigation during the entire vegetation period.

Effects of Varying Nutrient Solution to Brassica Rapa “Bokchoy” Grow Under Hydroponic System

The fact that farming is dependent on available land becomes even more complex when the climate is changing drastically. From this perspective, soilless system production is advantageous since it allows farmers to utilize land that has been unproductive due to pollution or illness, while simultaneously reducing the quantity of water consumed. According to the discussion and conclusions that accompany the results, the growth and development of Brassica rapa are affected by the nutrients it receives in treatments. The concentrations of nutrient solutions have a significant impact on the growth of Brassica rapa. As the number of Brassica rapa layers increases, the Brassica rapa yield increases and improves, particularly in terms of plant yield. The effects of nutritional solutions on plant growth, fresh weight, water consumption, and the number of nutrients in leaf tissue demonstrated that the interactions between factors are not the same. According to the findings of the study, the collected nutrients could be used as fertilizer. Therefore, hydroponic systems will require less mineral fertilizer. The environmental temperature is one of the most important abiotic factors that could slow down the process of development, production, and spread. Based on the data, it is feasible to conclude that the cultivar is more resistant to cold stress.

Potassium Ion‐selective Electrode with a Sensitive Ion‐to‐Electron Transducer Composed of Porous Laser‐induced Graphene and MoS2 Fabricated by One‐step Direct Laser Writing

AbstractIn this study, an ion‐selective electrode with a sensitive ion‐to‐electron transducer composed of porous laser‐induced graphene (LIG) and MoS2 (LIG‐MoS2/ISE) was fabricated to measure the potassium ion concentration in a greenhouse nutrient solution for soilless culture. Additionally, a more effective and low‐cost method was proposed for the large‐batch production and manufacture of potassium ion‐selective electrodes (K+‐ISEs) using the direct laser writing technique, which differs considerably from existing methods. Moreover, the sensing mechanism of the proposed LIG‐MoS2/ISE for potassium ion detection was investigated. The morphology and physical properties of the LIG‐MoS2/SC‐K+‐ISEs were studied by X‐ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and energy‐dispersive spectroscopy. Potentiometric measurements, chronopotentiometry, potentiometric water layer tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to evaluate the analytical performance of the newly developed K+‐ISEs. A Nernstian slope of 30.1 mV/decade for the activity of potassium ions in a concentration range from 10−7 to 10−2 M was determined. The EIS and chronopotentiometry results revealed that the LIG‐MoS2/SC‐K+‐ISE had a larger resistance and double‐layer capacitance than the LIG/SC‐K+‐ISE. The ion‐selective membrane (ISM) and solid‐contact layer did not have any water film between them, according to the potentiometric water layer test. The results proved that the LIG‐MoS2 nanocomposite could possibly be used as a sensitive ion‐to‐electron transducer to fabricate K+‐ISEs. The K+‐ISE fabrication method using the direct laser writing technique had a higher efficiency, enabling its broad application prospects in agriculture.

Vegetative-phase Growth Performance of rice (Oryza sativa L.) Cultivated Using Hydroponic System

Rice (Oryza sativa L.) is the most important staple food for many countries including Malaysia. But the country is still relying on the import to meet its domestic demand. Though significant public resources allocated for the rice industry, rice cultivation is still perceived to be uneconomical and associated with poverty. Therefore, a hydroponic system is seen as an alternative rice cultivation system that possibly be able to overcome common problems encountered in conventional and traditional paddy cultivation such as irrigation systems, limited cultivation area, control of nutrient inputs, control of pests, and loss of community interest particularly the new generation towards paddy cultivation. This net house study which one of the objectives was conducted to examine the vegetative growth of two local rice varieties under hydroponic condition. The experiment was a split plot design with nutrient solution concentration as the main plot, and the subplot is a local rice variety consisting of low land variety TQR-8 Sri Aman and upland rice variety called as ‘Tadong’. Each treatment was replicated in four plants or pots. A two-way analysis of variance (ANOVA) was performed to determine the effect of nutrient solution concentration and variety on rice growth cultivated using hydroponic system. The results revealed that the hydroponically grown rice of TQR-8 Sri Aman has greater tillering ability compared to Tadong for both NCSs. On the other hand, Tadong variety showed higher plant height than TQR-8 Sri Aman grown under hydroponic system. In addition, interaction of variety and nutrient solution concentration was significantly difference on tiller number and plant height. Further analysis should be conducted to evaluate the yield and feasible of the rice grown using hydroponic system.

Quality and Fruit Productivity of the Second Truss Blooming Seedlings Depending on Concentration of Nutrient Solution in Cherry Tomato

이번 연구는 효과적으로 2화방 개화묘를 생산하여 조기에 토마토를 수확하고 수확 기간을 연장하기 위하여 적절한 양액 농도 관리방법을 구명하기 위해 실시되었다. 처리는 양액 농도로 1줄기 2화방 개화묘 연구에서는 양액 EC를 1.5, 2.0, 2.5dS·m-1, 동적 관리(3.0 → 3.5 → 4.5dS·m-1)로 공급하였다. 육묘기간은 65일로 관행묘에 비해 20－40일, 1화방 개화묘(큐브 육묘)보다는 10일 정도 길었다. 초장은 EC 2.5dS·m-1와 동적 관리는 각각 78, 77cm로 EC 1.5dS·m-1처리 88cm보다 짧았다. 정식 전 큐브 내 EC는 동적 관리가 EC 5.5dS·m-1로 가장 높았으며, EC 1.5dS·m-1로 공급한 큐브는 3.0dS/m으로 가장 낮았다. 2화방 개화묘에서 EC 처리 간 생산량 차이는 나타나지 않았으나 1화방 개화묘는 2화방 개화묘보다 생산성이 떨어졌다. 2화방 개화묘는 첫 수확일이 6월 4일로 정식 후 35일만에 수확하였으며 1화방 개화묘는 6월 11일로 42일만에 수확하였다. 절곡에 의한 초장 및 뿌리 생육의 차이는 나타나지 않았다. 2줄기 2화방 개화묘 생산 연구에서는 공급 양액 EC를 2.0, 2.5, 3.0dS·m-1, 동적 관리(3.0 → 3.5 → 4.5dS·m-1)로 하여 공급하였다. 육묘 기간은 90일로 관행묘에 비해 40－50일, 1화방 2줄기 개화묘(큐브 육묘)보다는 10일 정도 길었다. 초장은 공급 양액 EC 2.0dS·m-1에서 80cm, 2.5dS·m-1에서는 81cm였으며 3.0dS·m-1 처리에서는 75cm, 동적 관리에서는 73cm로 가장 짧았다. 배지 내 EC는 모든 처리에서 육묘 기간이 길어질수록 높아졌으며 특히 공급 EC가 가장 높았던 동적 관리 처리에서 EC 5.1dS·m-1로 가장 높았다. EC 처리 간 생산량 차이는 나타나지 않았으나 육묘 기간이 10일 정도 길었던 2화방 개화묘가 1화방 개화묘보다 15% 정도 생산량이 많았다. 2화방 개화묘의 초장을 짧게 만들기 위해서는 가식 후 공급 양액 농도를 높이는 방법이 가장 효율적인 방법으로 판단된다.

Sweet basil can be grown hydroponically at low phosphorus and high sodium chloride concentration: Effect on plant and nutrient solution management

Agronomic inputs in agriculture easily exceed crop needs causing environment pollution. Phosphorus (P) is a macronutrient largely used in agriculture as a mineral fertilizer that requires an accurate management because it is a finite and non-renewable resource. Growing plants hydroponically can optimize plant nutrition achieving high crop nutrient use efficiency. However, irrigation water of poor quality (saline) interferes with crop performance. In this study, the effects of different P and NaCl levels in the root zone were evaluated on basil plants grown in a deep liquid culture system in a growth chamber. Two experiments with different P (from 0.1 to 1.0 mol m−3) and NaCl (from 0 to 60 mol m−3) concentrations in the nutrient solution were carried out. Plant growth, leaf gas exchanges and fluorescence, uptake of minerals and water, and leaf quality (content of minerals and pigments, and antioxidant capacity) were analysed. The most relevant morphological plant response to the low P (i.e., roughly 0.1 x of a standard nutrient solution) concentration consisted in a greater root/shoot ratio. However, plants growing at low P concentration did not show any reduction in yield and quality. Sodium chloride did not significantly affect plants yield and quality up to a concentration of 30 mol m−3 confirming the tolerance of basil to moderate saline stress. Significant reduction in the total biomass, water uptake and photosynthesis instead occurred at NaCl 60 mol m−3. These results confirmed the hypotheses that basil can be grown hydroponically at low P and high NaCl concentration with proper management of the nutrient solution. The absence of significant interactions between P and NaCl suggests that these two factors can be managed independently with potential benefits for crop economic and environmental sustainability.

EFFECT OF SUBSTRATES AND FERTIGATION ON GROWTH AND PHOTOSYNTHETIC EFFICIENCY OF MAGUEY PULQUERO PLANTS OF MEZQUITAL VALLEY LANDRACES

Maguey pulquero (Agave spp.) seedling cultivation is an emerging alternative capable of supply the demand of its diverse products. This research aimed to evaluate the growth and maximum quantum yield of Photosystem II (Fv/Fm) of three landraces of maguey pulquero young plants (10 months-old) germinated from seeds, growing under greenhouse within interaction effect of four substrates and four concentration levels of nutrient solution. The hypothesis was that phenotypic variation of young maguey pulquero landraces growing under greenhouse conditions could help to identify genotypes ideal for commercial production and to elucidate its nutrient and substrate requirements. The variables evaluated were: Fv/Fm, number of leaves, length and width (cm) of biggest leaf, and plant dry biomass (g), the results were analyzed by a two-way ANOVA and means comparison by Tukey’s test. The results demonstrated that Penca larga landrace (Agave mapisaga Trel.) had the highest values in all the growth variables evaluated compared to Manso and Xamini landraces (both A. salmiana Otto ex Salm-Dyck). Penca larga exhibited similar growth in the substrate agricultural soil and volcanic scoria mixture (SVM), and substrate agricultural soil alone (S) regardless of the nutrient solution concentration used, while both A. salmiana landraces exhibited total biomass reduction in the maximum nutrient concentration added in the S substrate (S+L4 treatment) compared to their respective effect on SVM substrate without nutrient addition (SVM+L1 treatment). All landraces exhibited growth inhibition in the commercial substrate mixture (CSM) and volcanic scoria alone (VS) without nutrient addition (CSM+L1 and VS+L1), while growth increase of all landraces in those substrates was relative to the increasing nutrient concentration. Photoinhibition was observed in all landraces in the treatment VS+L1. The growth variations observed across the landraces were helpful to identify potential genotypes ideal for commercial production and to set adequate substrates and nutrient requirements for agave cultivation,

Condutividade elétrica da solução nutritiva no cultivo sem solo de couve rábano

ABSTRACT The electrical conductivity of the nutrient solution directly affects production and quality of the plants. We evaluated the electrical conductivity suitable for soilless cultivation of kohlrabi. The experiment was carried out in a completely randomized design, with four replicates and five treatments, composed of different nutrient solution’s conductivities (1.31, 1.71, 2.37, 2.98 and 3.75 dS m-1). We evaluated number of leaves, leaf area, specific leaf area, leaf area ratio, fresh and dry masses of leaves, bulb, roots and total, bulb volume, water content in the bulbs and pH, soluble solids, vitamin C, firmness, titratable acidity and SS/TA ratio of the bulbs. All variables related to growth were affected by the nutrient solutions, showing the highest values with the use of the nutrient solutions with EC close to 2.0 dS m-1. Considering the commercial part of the plant, the most developed bulbs were obtained with EC of 1.96 dS m-1, being 49.9 g and 41.15 cm3 per bulb. On the other hand, except for pH, the other variables responded to the increase of EC. Higher values for pulp firmness and titratable acidity occurred with EC close to 2.0 dS m-1, whereas the other variables showed higher values using a more concentrated nutrient solution.

Responses of wheat and barley to Acacia saligna leaf and stem extracts: influence on growth and ascorbate-glutathione cycle

The present study aimed to study the effect of dry leaf and stem leachates of Acacia saligna on wheat’s growth and enzyme functioning (Triticum aestivum) and barley (Hordeum vulgare). Leaf leachates (LL) and stem leachates (SL) of A. saligna were applied through root and nutrient solution in different concentrations i.e., 5, 10, and 15%. Treatment of LL and SL declined the growth in terms of height and dry weight in both tested plants in concentration-dependent manner with the maximal decline due to 15% LL. In addition, content of relative water, total chlorophylls, and carotenoids decreased in both wheat as well as barley. The activity of ascorbate peroxidase, monodehydro ascorbate reductase, dehydroascorbate reductase, and glutathione reductase increased considerably due to the treatment of LL and SL. The indigenous tolerance mechanisms in wheat and barley seedlings were further strengthened in wheat and barley by increased accumulation of glycine betaine, glutathione, and ascorbate in response to LL and SL treatment. Additionally, the activity of lipoxygenase and protease were increased significantly due to LL and SL treatment with a maximal increase at higher concentrations. From the present study it can be concluded that extracts of leaf and stem of A. saligna inhibit the growth of wheat and barley significantly with a concomitant increase in the functioning of the ascorbate-glutathione (AsA-GSH) cycle. Further, both crop species showed comparable responses to A. saligna leachates.

Biostimulatory Action of a Plant-Derived Protein Hydrolysate on Morphological Traits, Photosynthetic Parameters, and Mineral Composition of Two Basil Cultivars Grown Hydroponically under Variable Electrical Conductivity

Hydroponics is a viable alternative to open field cultivation for year-round vegetable production in urban areas. However, the total dependence on external chemical inputs (fertilizers) makes these systems often less environmentally sustainable. In this perspective, the use of biostimulants could represent a valuable and eco-friendly tool to limit the excessive use of fertilizers without a negative impact on the yield. To this end, our work aimed to evaluate the productive and physiological response of two cultivars of ‘Genovese’ basil (Eleonora and Italiano Classico) for the industrial production of “pesto” grown for 22 days in two nutrient solutions with different electrical conductivity (1 and 2 dS m−1) and the application of two doses of protein hydrolysates (0.15- and 0.30-mL L−1 of Trainer® in the nutrient solution). The mineral profile was evaluated by ion chromatography coupled with a conductivity detector, while pigments were evaluated by UV-Vis spectrophotometry. Generally, the nutrient solution concentration did not significantly affect the fresh yield of the two cultivars tested. On the contrary, the use of the maximum dose of biostimulant (BT2 = 0.30 mL L−1 of nutrient solution) increased fresh yield, leaf area, and ACO2 by 20.7, 27.5, and 17.6%, respectively, compared with the control. Using the lowest dose of biostimulant (BT1 = 0.15 mL L−1 of the nutrient solution) reduced nitrate by 6.6% compared with the control. The results obtained showed that basil cultivation in a floating raft system combined with biostimulant in the nutrient solution could be an excellent solution to improve productivity, reduce nitrate, and cut fertilizer costs.

Effect of Photoperiod and Nutritional-Shock on Increasing the Number of Minitubers from Apical Rooted Cuttings Grown in Coco-Peat

Currently, a variety of techniques for producing potato minituber have been investigated, including soilless aeroponic, hydroponic and deep-water culture systems. However, minitubers potato production in the greenhouse from apical rooted cutting grown coco-peat under a photoperiod and nutritional - shock system is a new and creative idea. Therefore, the objective of the study was to optimize the effect of photoperiod and nutritional-shock on growth performance and yield of first generation potato tuber production of potato plants. Potato variety ‘Atlantic’ was treated under 5 photoperiod – (8 h/day, 9 h/day, 10 h/day, 11 h/day and natural light) under nutritional-shock process with reducing N concentration in nutrient solution (0;25%; 50%;75% and 100%), the growth stage of plant to conduct nutritional-shock (30, 35, 40, 45 and 50 DAT), the implementation time of nutritional-shock (12, 24, 48 and 60 hours) and the combination of photoperiod (9 h/day, 10 h/day) and nutritional-shock (75%, 100%) on the formation and development of minitubers. The study revealed that photoperiod at 10h/day showed the best result with 7.4 tubers/ plant and 569.7 tubers m-2. The number of tuber stolons, average number of tubers and tuber yield was directly proportional to the decreasing in N concentration in the nutrient solution, in which the highest was the 100% reduction in N concentration with 9.3 tubers/plant, higher than the control treatment 300%. The nutrient shock treatment at 30 DAT in 48 ours gave the best tuber production efficiency. There was a strong interaction between photoperiod and nutritional-shock on the formation and yield of potatoes (10.6 tubers/plant, 308 tubers m-2).

Influence of the Electrical Conductivity of the Nutrient Solution in Different Phenological Stages on the Growth and Yield of Cherry Tomato

Soilless cultivation is an important alternative to traditional agriculture and facilitates harvest by allowing for the precise control of plant nutrients to maximize the vegetable production of uniform fruits. Nutrient solution concentration is a critical factor affecting nutrient supply in soilless cultivation. Although some nutrient solution concentrations throughout the growth cycle for tomatoes have been developed, there are limited studies on nutrient solution concentrations at different phenological stages. Hence, we studied the effects of nutrient solution concentrations in different growth stages on the physiology, yield and fruit quality of cherry tomatoes with a previously developed nutrient solution formulation. The whole growth cycle of the tomato was divided into three stages which were irrigated with a nutrient solution with different electrical conductivities (ECs). A total of five treatments were set: CK (EC was 3.0 ms·cm−1 for the 1st–3rd stage), T1 (EC was 1.5 ms·cm−1 for the 1st stage, 3.0 ms·cm−1 for the 2nd–3rd stage), T2 (EC was 1.5 ms·cm−1 for the 1st stage, 3.0 ms·cm−1 for the 2nd stage, 4.5 ms·cm−1 for the 3rd stage ), T3 (EC was 1.5 ms·cm−1 for the 1st–2nd stage, 3.0 ms·cm−1 for the 3rd stage), and T4 (EC was 1.5 ms·cm−1 for the 1st stage, 4.5 ms·cm−1 for the 2nd–3rd stage). The results showed that the tomato plants treated with T2 and T4 had the strongest growth (with the highest plant height and leaf formation) as well as the best leaf photosynthetic performance (the chlorophyll content and the net photosynthetic rate were significantly increased). Additionally, the use of T2 and T4 significantly improved cherry tomato fruit quality as reflected by the significant promotion of total soluble solids by 9.1% and 9.8%, respectively, as well as by the improvement of maturity by 12.9% and 13.7%, respectively. Additionally, the yields for treatments T2 and T4 were increased by 7.3% and 13.4%, respectively, which was mainly due to the increase in single fruit weight. More importantly, nutrient solution EC management improved fertilizer use efficiency: the partial fertilizer productivity of T1, T2, and T4 was increased by 2%, 7% and 14%, respectively, while that of T3 was reduced by 7%. A comprehensive comparison showed that the ranking of the effect on production was T4 > T2 > T1 > CK > T3. Our results suggest that the regulation of EC in different growth stages affects the growth and yield characteristics of cherry tomatoes. This study may provide some references for further research to adjust the concentration of nutrient solutions to improve the utilization rate of fertilizer and fruit quality.

White lupin (Lupinus albus L.) exposed to elevated atmospheric CO2 requires additional phosphorus for N2 fixation

PurposeThe steady rise of atmospheric CO2 concentrations enhances symbiotic N2 fixation and plant growth. However, it is largely unknown whether more P is required to enhance N2 fixation under elevated CO2. We examined if plants under elevated CO2 require more P to support enhanced N2 fixation.MethodsWhite lupin (Lupinus albus L. cv. Kiev) was grown in nutrient solution under ambient (380 ppm) and elevated (700 ppm) CO2 levels at 0, 2, 5, 12, 25 and 50 µM P. Nodulation, nodule function, N2 fixation and plant growth were assessed at 4 and 6 weeks post inoculation. Excess cation uptake and proton release were also analysed due to its importance in P acquisition.ResultsElevated CO2 increased the critical P concentration in nutrient solution for N2 fixation, indicating plants under elevated CO2 need to acquire additional P to support greater N2 fixation. Elevated CO2 improved N2 fixation in P-deficient plants by increasing specific nitrogenase activity. Elevated CO2 also enhanced excess cation uptake which increased proton release by roots.ConclusionsAs elevated CO2 increased the plant demand for P, it increased the critical P concentration in nutrient solution for N2 fixation, thereby plants require more P to mitigate the effect of P deficiency on N2 fixation. Despite this, elevated CO2 could enhance N2 fixation in P-limiting environments.