Hydroponic Medium Research Articles

Root system architecture, physiological analysis and dynamic transcriptomics unravel the drought-responsive traits in rice genotypes

Drought is the major abiotic factors that limit crop productivity worldwide. To withstand stress conditions, plants alter numerous mechanisms for adaption and tolerance. Therefore, in the present study, 106 rice varieties were screened for drought tolerance phenotype via exposing different concentrations of polyethylene glycol 6000 (PEG) in the hydroponic nutrient medium at the time interval of 1, 3, and 7 days to evaluate the changes in their root system architecture. Further, based on root phenotype obtained after PEG-induced drought, two contrasting varieties drought-tolerant Heena and -sensitive Kiran were selected to study transcriptional and physiological alterations at the same stress durations. Physiological parameters (photosynthesis rate, stomatal conductance, transpiration), and non-enzymatic antioxidants (carotenoids, anthocyanins, total phenol content) production indicated better performance of Heena than Kiran. Comparatively higher accumulation of carotenoid and anthocyanin content and the increased photosynthetic rate was also observed in Heena. Root morphology (length, numbers of root hairs, seminal roots and adventitious roots) and anatomical data (lignin deposition, xylem area) enable tolerant variety Heena to better maintain membrane integrity and relative water content, which also contribute to comparatively higher biomass accumulation in Heena under drought. In transcriptome profiling, significant drought stress-associated differentially expressed genes (DEGs) were identified in both the varieties. A total of 1033 and 936 uniquely upregulated DEGs were found in Heena and Kiran respectively. The significant modulation of DEGs that were mainly associated with phytohormone signaling, stress-responsive genes (LEA, DREB), transcription factors (TFs) (AP2/ERF, MYB, WRKY, bHLH), and genes involved in photosynthesis and antioxidative mechanisms indicate better adaptive nature of Heena in stress tolerance. Additionally, the QTL-mapping analysis showed a very high number of DEGs associated with drought stress at AQHP069 QTL in Heena in comparison to Kiran which further distinguishes the drought-responsive traits at the chromosomal level in both the contrasting varieties. Overall, results support the higher capability of Heena over Kiran variety to induce numerous genes along with the development of better root architecture to endure drought stress.

Biomechanics of Atlas Cedar Roots in response to the Medium Hydromechanical Characteristics.

The biomechanical root flexibility in response to hydromechanical soil heterogeneity is the most determining factor of the root architecture which plays a paramount role in mycorrhizal infection and allows the seedlings to adapt to the environmental constraint. We examined the impact of five different hydromechanical medium properties (hydroponics, vermiculite, vermiculite-gravel, sawdust, and sand) on the morphology, physiology, and anatomy of Cedrus atlantica seedlings at a controlled growth chamber. The growth of the seedling is strongly stimulated by the hydroponic medium through the stimulation of the aerial part dry weight and the main root length. However, the sand medium increases the main root dry weight by the radial expanse stimulation at the level of the epidermis, vascular cylinder, and cortex and compensates the less root architecture by the stimulation of the xylem and phloem areas. In contrast to sand and hydroponic media, the sawdust medium stimulates the phloem/xylem ratio, the root architecture, and the short roots. The Pearson bilateral correlation shows that the aerial part dry weight is positively correlated with the permeability, porosity, and water-holding capacity and negatively with the bulk density and density at saturation, whereas the short root production is negatively correlated with the permeability and water-holding capacity. Hence, the hydromechanical characteristics of the soils must be taken into account in the reforestation and mycorrhization attempts.

Investigating the genetic variability of 12 Vietnamese rice accessions (Oryza sativa L.) in response to phosphorus deficiency

Phosphate is the second major factor limiting on crop productivity and leads to various physiological disorders that would consequently affect plant development. In response to phosphate starvation, plants have to improve their root systems for efficiently acquired phosphate. In Vietnam, rice is one of the most important agricultural crops in which 60% of the rain-fed lowland rice is cultured on soil types, which are low in phosphorus or phosphate fixing. This fact along with the scenario in which phosphate resources are running out in fast pace, highly provoked an indispensible need for developing new rice varieties with high productivity under low phosphate condition. An emerging approach in order to accomplish this goal is through genetic improvement of local rice resources. Taking advantage of that, in this study, out of 182 sequenced Vietnamese rice accessions, 12 representatives from 3 distinguishing rice groups: Indica, Japonica and admix Indica subgroup were chosen. The variation in number of crown root, root length, shoot length, root mass, shoot mass, chlorophyll content and root anatomy were examined as parameters to analyze the effect of phosphorus deficiency (1 µM) compare to full phosphate medium (300 µM). The minimum number of plantlets used for each condition was 15. Each genotype was grown in Yoshida hydroponic medium (changed every 4 days, harvesting was made after 14 days). The experimental results showed a remarkable variation of different rice accessions in response to phosphate deficiency. The starvation of phosphate significantly affected almost all examined traits in which several accessions such as G38, G93, G165, G223, G62 accessions were potential hypersensitive and G11, G177 accessions were potential tolerant to P deficiency. These results are interesting and encouraging to further research for screening our Vietnamese rice collection in order to identify the set of potential genes responsible for tolerance in phosphorus starvation condition.

The auxin-resistant dgt tomato mutant grows less than the wild type but is less sensitive to ammonium toxicity and nitrogen deficiency

The low-auxin-sensitivity tomato mutant, dgt, despite displaying reduced plant growth, has been linked to greater resistance to N deficiency. This led us to test the role of auxin resistance of dgt in NH4+ toxicity and N deficiency, compared to wild type tomato (cv. Micro-Tom, MT), grown in hydroponic media. A completely randomized design with three replications in a 2 × 4 factorial scheme was adopted, corresponding to the two tomato genotypes (MT and dgt), involving four nutritional treatments: NO3− (5 mM); NH4+ (5 mM); NO3− (5 mM) plus exogenous auxin (10 μM IAA); and N omission. The results show that NH4+ was toxic to MT but not to dgt. Under N deficiency, MT displayed a lower shoot NO3− content, a lower photosynthetic rate, and a decrease in both shoot and root dry weight. However, in dgt, no difference was observed in shoot NO3− content and photosynthetic rate between plants grown on NO3− or under N deficiency. In addition, dgt showed an increase in shoot dry weight under N deficiency. We highlight the role of auxin resistance in the adaptation of plants to NH4+ toxicity and N deficiency.

Performance evaluation of hydroponic system for co-cultivation of microalgae and tomato plant

Conventional hydroponic units producing disease free plants with 30–40% faster growth rate are regarded as a promising agricultural alternative in case of unfertile/metal contaminated soil. However, most nutrients in hydroponics medium remain unused and are drained off creating environmental pollution. To reduce the nutrient load and eutrophication effects, cocultivation of plant and microalgae in the hydroponic units has attracted the attention of researchers over the past few years. The present study aims to explore the influence of initial inoculum concentration of a native algal consortium over the performance of hydroponic system. Cocultivation of tomato plant with varying initial inoculum algal concentration of 0.2–0.8 mg/ml, showed that 0.8 mg/ml concentration resulted in positive interactions between microalgae and plant, with algal and plant productivity of 0.149 ± 0.024 and 0.328 ± 0.087 g/m2/d respectively after 42 days. Higher chlorophyll accumulation, along with nutritionally rich algal and plant biomass revealed lack of unwanted competition during cocultivation. Increase in dissolved oxygen during cocultivation was corroborated with efficient root respiration. Highly developed roots also provided adequate metabolic energy thus significantly increasing the nutrient uptake and accumulation, thereby reducing the nutrient load during drainage. The supernatant after algal harvesting (recycled media) supported plant growth for 24 days due to limited nutrients. Such system with microalgae symbiotically favouring plant productivity and simultaneous nutrient load reduction would ultimately support in attaining sustainable agriculture.

Root morphology and exudate availability are shaped by particle size and chemistry in Brachypodium distachyon.

Root morphology and exudation define a plants’ sphere of influence in soils. In turn, soil characteristics influence plant growth, morphology, root microbiome, and rhizosphere chemistry. Collectively, all these parameters have significant implications on the major biogeochemical cycles, crop yield, and ecosystem health. However, how plants are shaped by the physiochemistry of soil particles is still not well understood. We explored how particle size and chemistry of growth substrates affect root morphology and exudation of a model grass. We grew Brachypodium distachyon in glass beads with various sizes (0.5, 1, 2, 3 mm), as well as in sand (0.005, 0.25, 4 mm) and in clay (4 mm) particles and in particle‐free hydroponic medium. Plant morphology, root weight, and shoot weight were measured. We found that particle size significantly influenced root fresh weight and root length, whereas root number and shoot weight remained constant. Next, plant exudation profiles were analyzed with mass spectrometry imaging and liquid chromatography–mass spectrometry. Mass spectrometry imaging suggested that both, root length and number shape root exudation. Exudate profiles were comparable for plants growing in glass beads or sand with various particles sizes, but distinct for plants growing in clay for in situ exudate collection. Clay particles were found to sorb 20% of compounds exuded by clay‐grown plants, and 70% of compounds from a defined exudate medium. The sorbed compounds belonged to a range of chemical classes, among them nucleosides, organic acids, sugars, and amino acids. Some of the sorbed compounds could be desorbed by a rhizobacterium (Pseudomonas fluorescens WCS415), supporting its growth. This study demonstrates the effect of different characteristics of particles on root morphology, plant exudation and availability of nutrients to microorganisms. These findings further support the critical importance of the physiochemical properties of soils when investigating plant morphology, plant chemistry, and plant–microbe interactions.

Strontium Uptake and Effects in Hydroponically Cultivated Celery

The artificial radionuclide 90Sr is the main radionuclide in radioactive environmental pollution. In this study, celery was cultured in a laboratory hydroponics system for 21 days with strontium (Sr) levels of 0 (control), 0.5, 1, 2.5, 5, and 10 mM. The changes in the Sr contents in celery leaves and roots as well as the translocation factor (TF) values (ratio of the Sr concentration in aerial plant parts to that in roots) under different Sr concentrations were studied. Additionally, the effects of Sr stress on the absorption of six nutrients, the chlorophyll content, and the biomass of the celery were investigated. The results showed that the Sr contents in celery leaves and roots increased with the increasing Sr concentration in the hydroponic solution, but the increase of the Sr concentration in roots slowed under the 10 mM Sr treatment. The mean TF values ranged from 0.40 ± 0.01 to 1.12 ± 0.17. With the increase in Sr concentration in the hydroponic medium, the contents of calcium, iron, and potassium in the celery leaves were significantly reduced, and the absorption of calcium, iron, and magnesium by roots was significantly inhibited. Compared with the control, sulfur concentration in celery roots increased significantly under the Sr treatments increasing except the 10 mM Sr treatment. The changes in chlorophyll content were consistent with those of celery biomass, and the values of both these parameters were high under the 5 mM Sr treatment.

Reduced cadmium accumulation in tobacco by sodium chloride priming.

Cadmium (Cd) pollution threatens agricultural security worldwide. This study tested the efficacy of priming chemicals to decrease Cd uptake by tobacco plants (Nicotiana tabacum). After initial screening from nine different chemicals (NaCl, Cd(CH3COO)2, Cd(NO3)2, CdCl2, KHNO3, polyethylene glycol 6000 (PEG-6000), indole-3-acetic acid (IAA), ß-aminobutyric acid (BABA), and glutathione (GSH)), NaCl and PEG-6000 were further investigated because of their low risks to plant growth and efficiency to Cd reduction. Priming procedures (concentrations) were optimized for both chemicals and the best one (100 mM NaCl) was used to test both soil and hydroponic media. The results showed 31.3% lower Cd concentrations in shoots after priming with 100 mM NaCl. Phenotype parameters of the plants were also measured and showed no significant impacts of the priming procedures on the shoot biomass and the uptakes of nitrogen (N), phosphorus (P), and potassium (K), nor the photosynthetic capacity (net photosynthesis rate (Pn) and chlorophyll concentration (SPAD)). Histological observations of the roots showed a significant increase of the stele diameter after NaCl priming and a subsequent negative correlation between shoot Cd concentration and stele diameter was found after NaCl priming at different levels. This study confirmed 100 mM NaCl as an efficient priming treatment to decrease Cd uptake and the coarsening of the root stele was identified as a potential explanation for the observed decrease of Cd in tobacco shoots.

Metabolic regulations in lettuce root under combined exposure to perfluorooctanoic acid and perfluorooctane sulfonate in hydroponic media

Per- and polyfluoroalkyl substances (PFASs) have been detected in many agricultural products in contaminated fields and in supply chains. Roots are the main organ in plants to uptake and bio-accumulate PFASs, but the changes of metabolic regulation in roots by PFASs are largely unexplored. Here, lettuce exposed to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at different concentrations (500, 1000, 2000 and 5000 ng/L) was investigated via metabolomics. Many key metabolites, such as antioxidants, lipids, amino acids, fatty acids, carbohydrates, linolenic acid derivatives, purine and nucleosides, were significantly altered. Tyrosine metabolism, purine metabolism, isoquinoline alkaloid biosynthesis and terpenoid backbone biosynthesis were altered in roots by PFOA and PFOS. Tricarboxylic acid cycle was perturbed by 5000 ng/L exposure. Activation of antioxidant defense pathways, reallocation of carbon and nitrogen metabolism, regulation of energy metabolism and purine metabolism were reprogrammed in roots. Lettuce employed multiple strategies to increase tolerance to PFOA and PFOS, which includes the adjustment of membrane composition, elevation of inorganic nitrogen fixation and respiration, accumulation of sucrose and regulation of signaling molecules. The results of this study offer insights into the molecular reprogramming of plant roots in response to PFAS exposure and provide important information for the risk assessment of PFASs in environment.

Insights into the accumulation and transformation of Ch-SeNPs by Raphanus sativus and Brassica juncea: Effect on essential elements uptake

Selenium (Se) at very low doses has important functions for humans. Unfortunately, the low levels of Se in soils in various regions of the world have implemented the agronomic biofortification of crops by applying Se-enriched fertilizers (mainly based on selenate). Lately, the use of nanofertilizers is growing in interest as their low size reduces the amount of chemicals and minimizes nutrient losses in comparison with conventional bulk fertilizers. However, the knowledge on their fate and environmental impact is still scarce. This study aims to evaluate the biotransformation of chitosan-modified Se nanoparticles (Ch-SeNPs) as well as their effect on the metabolism of essential metals (Fe, Cu, Zn and Mo) when applied to hydroponic cultivation of R. sativus and B. juncea. In house-synthesized Ch-SeNPs were characterized in both synthesis and hydroponic culture media by transmission electron microscopy (TEM), dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The composition of one-tenth strength Hoagland's solution did not affect the size, shape and concentration in number of particles per mL of Ch-SeNPs. The plants were grown inside a box at 25 °C during the months of May–July in 2018. After a week of treatment with Ch-SeNPs, plants were harvested and divided into roots and aerial part. The biotransformation of Ch-SeNPs was evaluated through a process of enzymatic hydrolysis and subsequent analysis by HPLC-ICP-MS and HPLC-ESI-MS/MS. The results confirmed the transformation of Ch-SeNPs to seleno-amino acids: Selenomethionine (SeMet), Semethylselenocysteine (SeMetSeCys) and ɣ-glutamyl-Se-MetSeCys. Moreover, Multiple-way analysis of variance (ANOVA) and principal component analysis (PCA) showed that, regardless the plant species, Ch-SeNPs supplementation affected the absorption of Zn.

Efficacy of fenugreek plant for ascorbic acid assisted phytoextraction of copper (Cu); A detailed study of Cu induced morpho-physiological and biochemical alterations

Phytoremediation via phyto-extraction is well recognized and sustainable principle for the economical removal of heavy metals from contaminated water and soil. The twofold objective of the present research work was to investigate the remediation potential of fenugreek for Cu under the influence of ascorbic acid (AA). The effect of copper-ascorbic acid chelation on the growth regulation of fenugreek (Trigonella foenum-graceum L.) and its potential to accumulate Cu was investigated in hydroponic medium to optimize concentration with complete randomized design (CRD). Juvenile fenugreek plants were treated with different treatments of AA (5 mM) and Cu (100, 250 and 500 μM). The different morpho-physiological parameters of fenugreek plant such as growth, biomass and chlorophylls were significantly reduced under Cu stress. However, the activities of antioxidant enzymes, electrolyte leakage and reactive oxygen species enhanced with increasing concentration of applied Cu. Results indicated significant increase in plant growth, biomass, physiology and antioxidant enzymes and decrease in reactive oxygen species and electrolyte production in AA mediated fenugreek plants compared to controls and Cu only treated plants. However, it was also found that AA enhanced Cu concentration maximum up to 42% in leaf, 18% in stem and 45% in roots as compared to Cu treated only plants. Moreover, application of AA signified the research results revealing to act as growth regulator and chelator under Cu stress.

Phytoremediation potential of switchgrass (Panicum virgatum), two United States native varieties, to remove bisphenol-A (BPA) from aqueous media

Plastic wastes burdening Earth’s water and accumulating on land, releasing toxic leachates, are one of the greatest global threats of our time. Bisphenol-A (BPA), a potent endocrine disrupting compound, is a synthetic ingredient of the polycarbonate plastics and epoxy resins used in food containers, cans, and water bottles. Bisphenol-A’s rising concentrations in the environment require a sustainable alternative to current removal practices, which are expensive and/or ecologically unsafe. Switchgrass offers a safe alternative. To investigate its potential for BPA removal, two United States native switchgrass varieties where tested in hydroponic media. Results show minimal hydrolysis and photolysis of BPA over 55 days, confirming its persistence. Both generic and heavy metal switchgrass exhibited statistically significant (p < 0.0001) BPA removal (40% and 46%, respectively) over approximately 3 months, underscoring switchgrass’s effectiveness for BPA removal. Significantly higher (p < 0.005) BPA accumulation in roots than shoots and nonsignificant variances in biomass, chlorophyll (p > 0.19), and peroxidase between BPA-treated and untreated plants indicates substantial BPA tolerance in both varieties. Kinetic parameters of BPA removal and translocation factors were also determined, which will inform the design of BPA removal phytotechnologies for a variety of soil conditions, including landfills where BPA accumulation is greatest.

The Growth Characteristics of Three Terrestrial Plants Cultivated with Biogas Slurry as a Hydroponic Medium

Biogas slurry is a traditional high-quality organic liquid fertilizer. Three terrestrial plants with high economic value, fu gui cai, yang xin cai and strawberry, were selected for hydroponic cultivation using an optimal dilution of biogas slurry. The results of the experiments showed that strawberries could bloom and bear fruit and fu gui cai and yang xin cai grew well. However, in comparison with the control groups planted in soil, all three crops were subject to a certain degree of environmental stress, as shown by changes in growth, biomass indicators, physiological indicators and morphological indicators. The leaves and stems of yang cai and fu gui cai were tested for several types of heavy metals, and all met the requirements for human consumption. It is feasible to cultivate these three plants with biogas slurry. The results of this study can help guide hydroponic production practices and have practical significance and reference value.

The environment behavior of organophosphate esters (OPEs) and di-esters in wheat (Triticum aestivum L.): Uptake mechanism, in vivo hydrolysis and subcellular distribution

To reveal the metabolic characteristic of organophosphate esters (OPEs) in plants, uptake efficiency, subcellular distribution and hydrolysis of OPEs and their hydrolysis metabolites in wheat (Triticum aestivum L.) were investigated by hydroponic experiments. Tris(2-chloroethyl) phosphate (TCEP) and bis(2-chloroethyl) phosphate (BCEP) were prone to transporting to shoots by transpiration stream, with the translocation factors of 6.2 and 21 for TCEP and BCEP, respectively, as greater than 40% of TCEP and BECP were distributed in the cell sap due to their hydrophilicity. Hydrophobic OPEs (i.e. tri-n-butyl phosphate [TnBP] and triphenyl phosphate [TPhP]), and their hydrolysis metabolites (di-n-butyl phosphate [DnBP] and diphenyl phosphate [DPhP]) were stored in roots, resulting in low translocation capacity in wheat. As organophosphate diesters with relatively high proportions in cell walls (70–84% of DnBP and 41–43% of DPhP) are difficult to being transmembrane transported due to electrical repulsion of the cytomembrane, it is supposed that cell walls could be a main location for in vivo hydrolysis of OPEs. For DnBP, absorption by roots after in vitro hydrolysis of TnBP in hydroponic media was also an important source in wheat. Inhibition experiments showed that it is usually a non-energy-consuming process for root uptake of OPEs and their hydrolysis metabolites. The uptake of OPEs (i.e. TCEP, TnBP, and TPhP) and DPhP were facilitated diffusion mediated by aquaporins or anion channels, while uptake of BCEP and DnBP were simple diffusion processes. This study illustrated the distribution characteristics and translocation capacity of OPEs and their diester metabolites at the subcellular level.

Phytotoxicity induced by perfluorooctanoic acid and perfluorooctane sulfonate via metabolomics

Poly- and perfluoroalkyl substances (PFASs) are becoming common pollutants in natural environment, while the toxic effects and defense mechanisms in agricultural plants are poorly understood. Here, lettuce exposed to either perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS) at two different concentrations (500, 5000 ng/L) in hydroponic media was investigated via metabolomics. Under the tested conditions, the growth and biomass of lettuce were not affected by PFOA and PFOS, but metabolic profiles in leaves were altered. The composition and metabolism of lipids, carbohydrates, fatty acids, amino acids and some antioxidants were regulated, compromising the nutritional quality of the plants. Key pathways in energy metabolism were disturbed by both PFOA and PFOS, including tricarboxylic acid cycle, glyoxylate and dicarboxylate metabolism and pyruvate metabolism. Amino acid metabolism, e.g., phenylalanine and tyrosine, was disturbed by PFOA. The metabolism of linoleic acid was disturbed by PFOS. The changes of antioxidants and 8-hydroxy-deoxyguanosine indicated the occurrence of oxidative stress and DNA damage under PFOA or PFOS exposure. The main defense processes against PFASs exposure in lettuce included alteration in plasma membrane, activation of antioxidant systems, increase of tolerance and repair of DNA injury. These findings help elucidate the response of plants to PFASs in a molecular-scale perspective.

SOCIALIZATION OF VILLAGE GREENING THROUGH HYDROPONIC PLANTS TO UTILIZE LITTLE LAND IN SUKAMULYA, ANGGADITA VILLAGE, KLARI, KARAWANG

The development of the industrial area in Karawang precisely in Klari Anggadita village made green land very limited. In addition, the level of air pollution has also increased both from road dust, large vehicles, and factories. Limited greening areas, the Community Service Team of Mercu Buana University provides training in planting practices using Hydroponic media. Hydroponics is a farming technique without using soil media. On the other hand, hydroponics is cultivation by utilizing water without emphasizing meeting the nutritional needs of plants. Water requirements in hydroponics are less than water requirements in aquaculture with soils. Hydroponics uses water more efficiently, so it is suitable to be applied in arid regions such as Anggadita village. This training was held for one day and its growth was monitored for 2 months. During the course of time, the Community Service Team at Mercu Buana University also provided plant maintenance techniques using Hydroponic media.

Perfluorooctanoic acid and perfluorooctane sulfonate co-exposure induced changes of metabolites and defense pathways in lettuce leaves

Growing evidence shows plants are at risks of exposure to various per- and polyfluoroalkyl substances (PFASs), however the phytotoxicity induced by these compounds remains largely unknown on the molecular scale. Here, lettuce exposed to both perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at different concentrations (500, 1000, 2000 and 5000 ng/L) in hydroponic media was investigated via metabolomics. Under the co-exposure conditions, the growth and biomass were not affected by PFOA and PFOS, but metabolic profiles of mineral elements and organic compounds in lettuce leaves were significantly altered. The contents of Na, Mg, Cu, Fe, Ca and Mo were decreased 1.8%–47.8%, but Zn was increased 7.4%–24.2%. The metabolisms of amino acids and peptides, fatty acids and lipids were down-regulated in a dose-dependent manner, while purine and purine nucleosides were up-regulated, exhibiting the stress response to PFOA and PFOS co-exposure. The reduced amounts of phytol (14.8%–77.0%) and abscisic acid (60.7%–73.8%) indicated the alterations in photosynthesis and signal transduction. The metabolism of (poly)phenol, involved in shikimate-phenylpropanoid pathway and flavonoid branch pathway, was strengthened, to cope with the stress of PFASs. As the final metabolites of (poly)phenol biosynthesis, the abundance of various antioxidants was changed. This study offers comprehensive insight of plant response to PFAS co-exposure and enhances the understanding in detoxifying mechanisms.

Effects of Ascorbic Acid and Copper Treatments on Metallothionein Gene Expression and Antioxidant Enzyme Activities in Helianthus annuus L. Exposed to Chromium Stress

Heavy metal pollution, which is one of the most important environmental problems, has a significant effect on plant growth and development. Plants influence all living things because of their role in the food chain. Therefore, in this study, antioxidant enzyme activities and metallothionein (MT) gene expression levels were investigated to determine the protective role of copper (Cu) and ascorbic acid (AsA) against chromium (Cr) stress. In order to determine these parameters, sunflower seeds were grown in hydroponic system after germination. Two weeks later, AsA (200 mg/L) treatment was made as foliar spray. After 24 h of the treatment, the hydroponic nutrient medium was used as the treatment solution containing different concentrations of metals (0.25 mM Cu (CuSO4·5H2O); 1 mM Cr (K2Cr2O7). The results have reduced the overall growth of plants with Cr heavy metals. Cr stress increased the amount of malondialdehyde. Furthermore, while superoxide dismutase and peroxidase activities were increased, no significant change in catalase activity was observed. Cu and AsA applied with Cr treatment significantly reduced Cr toxicity. Expression levels of MT genes (HanMT2-1 and HanMT4) were determined by qRT-PCR analysis. From the study result, it was determined that the expression levels of MT genes under Cr stress changed according to the plant tissues and were upregulated in the roots. The protective roles of Cu and AsA against Cr stress were observed. From the results of this study, it was confirmed that MT2-1 could be an effective gene resource in Cr remediation-related plant breeding programs.

Biological synthesis of bimetallic nanoparticles of cobalt ferrate CoFe2O4 in an aqueous extract of Petroselinum crispum

Synthesized CoFe2O4 nanopowders in an aqueous extract from the leaves of Petroselinum crispum (“Green” synthesis) in an acidic and alkaline medium. Physical and chemical certification of the synthesized nanomaterials by UV spectrophotometry and scanning electron microscopy (SEM) was carried out. According to the UV spectra of CoFe2O4, obtained in an acidic medium, had a small shoulder at 242 nm and a peak at 292 nm, while the particles of alkaline nature had a plateau starting from 229 nm and a peak at 366 nm. SEM found that the synthesis environment also affects the morphology and size of CoFe2O4 bimetallic powders: during the synthesis in an alkaline medium, the particles were hemispherical in size from 30 to 100 nm, and in a slightly acidic medium (pH = 2), larger particles with cut diamond. The biological activity of cobalt ferrate was shown on the tolerance dynamics of Triticum vulgare L. plants (wheat). Wheat plants were grown in a hydroponic medium with the addition of CoFe2O4 nanoparticles in the range from 10–5 to 10–1 M to 14 days. CoFe2O4 powders of an acidic nature at concentrations of 10–2, 10–3, and 10–5 M reliably increased seed germination relative to intact samples by 48, 37, and 11%, respectively. In turn, CoFe2O4, synthesized in an alkaline medium, increased the index at dilutions of 10-3 and 10-4 M to 4 and 28%. A detailed analysis of metric indicators of T. vulgare seedlings after 14 days of exposure to CoFe2O4 allowed us to establish a higher resistance of test plants to nanopowders synthesized in an acidic medium. So, when exposed to particles synthesized in an acidic medium, in concentrations from 10-1 M to 10-5 M, an increase in the plant tolerance index of plants from 4 to 14% of the control was recorded. Alkaline CoFe2O4, under the same conditions, increased the rate from 1.2 to 16%. The intensity of the effect on the pigment apparatus of T. vulgare plants also depended on the synthesis conditions for CoFe2O4: at pH = 2, the amount of chlorophyll a decreased by no more than 2 times relative to the control, at pH = 9 - from 2 to 5 times (P≤0, 05).

Green synthesis of zinc based nanoparticles zinc ferrite by Petroselinum crispum

Zinc ferrite nanoparticles (ZnFe2O4) are being increasingly investigated due to their wide biological application. In this study, zinc ferrite nanoparticles were synthesized by green method using Petroselinum crispum. The synthesized magnetic nanoparticles were characterized using SEM technique. The biological activity of the preparations produced was studied on a test plant of wheat Triticum vulgare L. Wheat plants were grown in hydroponic medium with the addition of ZnFe2O4 nanoparticles in concentrations ranging from 10−5 to 10−1 M. On the third day, the germination rate of wheat seeds was calculated. The results showed that powders of acidic nature (pH=2) significantly reduced seed germination relative to the intact samples at concentrations of 10−3 and 10−4 M (by 100 and 47% relative to the control, respectively). ZnFe2O4 synthesized in alkaline medium reduced the germination rate to a lesser extent, and at similar concentrations – to 7.3 and 22.8%. Moreover, at the minimal concentration of 10−5 M, there was a slight increase in germination up to 19.3%. Cell viability of seedling roots was evaluated by transformation of the water-soluble tetrazolium salt to formazan (WST-test). Higher cell viability was observed after exposure to zinc ferrite produced in alkaline medium as compared to preparations produced in acidic medium. Particles synthesized in acidic medium at the concentration ranging from 10−1 to 10−5 M decreased cell viability to 77% relative to the control samples, and the preparation produced in alkaline medium under similar conditions reduced the rate only at maximum concentrations of 10−1 and 10−2 M to 53%. In the case of treatment of 10−5 M ZnFe2O4 of alkaline nature, cell viability was observed to grow up to 23% relative to the control samples.