Concentrations In Plant Tissues Research Articles

Comparative transcriptomic analysis revealed important processes underlying the static magnetic field effects on Arabidopsis.

Static magnetic field (SMF) plays important roles in various biological processes of many organisms including plants, though the molecular mechanism remains largely unclear. Here in this study, we evaluated different magnetic setups to test their effects on growth and development on Arabidopsis (Arabidopsis thaliana), and discovered that plant growth was significantly enhanced by inhomogeneous SMF generated by a regular triangular prism magnet perpendicular to the direction of gravity. Comparative transcriptomic analysis revealed that auxin synthesis and signal transduction genes were upregulated by SMF exposure. SMF also facilitated plants to maintain the iron homeostasis. The expression of iron metabolism-related genes was downregulated by SMF, however, the iron content in plant tissues remains relatively unchanged. Furthermore, SMF exposure also helped the plants to reduce ROS level and synergistically maintain the oxidant balance by enhanced activity of antioxidant enzymes and accumulation of nicotinamide. Taken together, our data suggested that SMF is involved in regulating the growth and development of Arabidopsis thaliana through maintaining iron homeostasis and balancing oxidative stress, which could be beneficial for plant survival and growth. The work presented here would extend our understanding of the mechanism and the regulatory network of how magnetic field affects the plant growth, which would provide insights into the development of novel plant synthetic biology technologies to engineer stress-resistant and high-yielding crops.

Plants as effective bioindicators for heavy metal pollution monitoring

This study investigated the bioindicator potential of Amaranthus retroflexus L., Plantago lanceolata L., Rumex acetosa L., and Trifolium pratense L. including the use of Lolium multiflorum L. as a reference species, for heavy metal pollution monitoring, in particular Zinc (Zn), Cadmium (Cd), Nickel (Ni), and Lead (Pb). Controlled heavy metal contamination was applied through irrigation with metal nitrate solutions two levels of contamination (low and high). The study also focused on analyzing heavy metals concentration in plant tissues and related physiological responses. Distinct physiological responses to heavy metal stress were observed among the investigated species, highlighting unique variations in their reactions. Hydrogen peroxide, malondialdehyde content, and enzymatic activities emerged as reliable indicators of plant stress induced by heavy metal solutions. P. lanceolata displayed elevated Zn concentrations in both roots and leaves (3271 ± 337 and 4956 ± 82 mg kg−1). For Pb, L. multiflorum and P. lanceolata showed highest root concentrations (2964 ± 937 and 1605 ± 289 mg kg−1), while R. acetosa had higher leaf concentration (1957 ± 147 mg kg−1). For Ni, L. multiflorum had the highest root concentration (1148 ± 93 mg kg−1), and P. lanceolata exhibited the highest leaf concentration (2492 ± 28 mg kg−1). P. lanceolata consistently demonstrated the highest Cd concentrations in both roots (126 ± 21 mg kg−1) and leaves (163 ± 12 mg kg−1). These results provide valuable insights for selecting effective bioindicator species to establish control strategies for heavy metal pollution.

Development of interactive learning media based on website chatbots on plant tissue material

The utilization of learning media is a valuable instrument in enhancing the learn-ing process, hence maximizing the attainment of learning objectives. The objec-tive of this study is to create an educational tool for biology instruction in the form of a website chatbot focused on plant tissue content. The research also seeks to evaluate the viability and efficacy of this tool when used by students. The pre-sent study used the ADDIE model, a widely recognized framework in the field of development research. This model encompasses five distinct stages, namely anal-ysis, design, development, implementation, and evaluation. The data utilized in this study was collected via interviews, questionnaires, and tests, and afterwards analyzed employing qualitative and quantitative descriptive statistical methods. The present study developed an educational tool in the form of a website chatbot focused on plant tissue materials. The validation process involved obtaining feed-back from media experts, material experts, and students. The assessment con-ducted by media experts resulted in a 91% rating, categorizing the chatbot as "very feasible." Similarly, the material expert's assessment yielded an 86.5% rat-ing, also falling into the "very feasible" category. Furthermore, students' respons-es indicated a 97.7% rating, categorizing the chatbot as "very feasible." Moreo-ver, based on the study conducted to evaluate the efficacy of learning media goods, the t-test findings revealed a significant difference between the pretest and post-test scores, as indicated by a Sig value (2-tailed) of 0.000, which is less than the predetermined significance level of 0.05. The mean gain for the website chat-bot learning media product is 0.77, falling inside the "high" category. This sug-gests that the product is very suited and effective as a learning medium.

Effects of Claroideoglomus etunicatum Fungus on the Growth Parameters of Maize (Zea mays L.) Plants under Boron Toxicity and Salt Stress

Soil salinity is an emerging phenomenon threatening arid and semiarid areas due to changing climatic events. Salinity, in combination with other elemental contaminants, can often harm crop performance and productivity. This experiment was conducted to evaluate the mitigating effect of Claroideoglomus etunicatum, an arbuscular mycorrhizal fungus (AMF), on combined boron (B) toxicity and salt stress symptoms in maize plants. After the stress and AMF treatments, plants were subjected to a wide range of analyses, such as AMF colonization rates, ion leakage, plant biomass, and concentration of B, phosphorus, sodium, potassium, iron, zinc, copper, and manganese in root and shoot tissues. The results showed that the combined stress did not affect the AMF colonization rate. AMF inoculation significantly increased plant biomass, the K+/Na+ ratio, and shoot B, sodium, and copper concentrations, but reduced root B concentrations and ion leakage. AMF inoculation slightly increased root dry weight and the sodium, potassium, zinc, copper and Mn contents in shoots under combined B and salinity stress, while AMF reduced the electrolyte leakage in leaves. It is inferred that AMF can ameliorate B toxicity in maize by improving biomass and reducing B concentration in plant tissues. Our research implies that C. etunicatum could be a valuable candidate for assisting in the remediation of boron-contaminated and saline soils.

Modified diatomite for soil remediation and its implications for heavy metal absorption in Calendula officinalis

BackgroundAmong different adsorbents, natural and inorganic compounds such as diatomite are important and advantageous in terms of high efficiency and cost-effectiveness, and function in stabilizing heavy metals in the environment. Calendula officinalis, a plant known as a high accumulator of heavy metals, was cultivated in soil treated with varying concentrations of modified diatomite to demonstrate the efficiency of modified diatomite in stabilizating of heavy metals in soils,ResultsThe modification of diatomite aimed to enhance Calendula officinalis adsorptive properties, particularly towards heavy metals such as lead (Pb), Zinc (Zn), Chromium (Cr), Nickle (Ni), and Copper (Cu), common contaminants in industrial soils. The experimental design included both control and treated soil samples, with assessments at regular intervals. Modified diatomite significantly decreased the bioaccumulation of heavy metals in contaminated soils except Zn, evidenced by decreased DTPA extractable heavy metals in soil and also heavy metal concentrations in plant tissues. Using 10% modified diatomite decreased 91% Pb and Cu, 78% Cr, and 79% Ni concentration of plants compared to the control treatment. The highest concentration of Zn in plant tissue was observed in 2.5% modified diatomite treatment. Remarkably, the application of modified diatomite also appeared to improve the nutrient profile of the soil, leading to enhanced uptake of key nutrients like phosphorus (P) 1.18%, and potassium (K) 79.6% in shoots and 82.3% in roots in Calendula officinalis. Consequently, treated plants exhibited improved growth characteristics, including shoots and roots height of 16.98% and 12.8% respectively, and shoots fresh and dry weight of 48.5% and 50.2% respectively., compared to those in untreated, contaminated soil.ConclusionThe findings suggest promising implications for using such amendments in ecological restoration and sustainable agriculture, particularly in areas impacted by industrial pollution.

Does spatial variation in insect herbivory match variations in plant quality? A meta-analysis.

Variation in herbivore pressure has often been predicted from patterns in plant traits considered as antiherbivore defences. Here, we tested whether spatial variation in field insect herbivory is associated with the variation in plant quality by conducting a meta-analysis of 223 correlation coefficients between herbivory levels and the expression of selected plant traits. We found no overall correlation between herbivory and either concentrations of plant secondary metabolites or values of physical leaf traits. This result was due to both the large number of low correlations and the opposing directions of high correlations in individual studies. Field herbivory demonstrated a significant association only with nitrogen: herbivore pressure increased with an increase in nitrogen concentration in plant tissues. Thus, our meta-analysis does not support either theoretical prediction, i.e., that plants possess high antiherbivore defences in localities with high herbivore pressure or that herbivory is low in localities where plant defences are high. We conclude that information about putative plant defences is insufficient to predict plant losses to insects in field conditions and that the only bottom-up factor shaping spatial variation in insect herbivory is plant nutritive value. Our findings stress the need to improve a theory linking plant putative defences and herbivory.

Evaluating Organic Fertilizers and Microbial Inoculation for Soilless and Hydroponic Crop Production

Because hydroponic operations in the United States can be certified as organic, and because the price of chemical fertilizers has increased, there is an increasing interest in using organic fertilizers and beneficial microorganisms for controlled-environment agriculture. However, there is a scarcity of information regarding their effectiveness and application methodologies. We investigated the effects of inoculating Azospirillum brasilense and Rhizophagus intraradices and using organic fertilizers on growing lettuce (Lactuca sativa ‘Cherokee’) and tomato (Solanum lycopersicum ‘Red Robin’) young plants in an indoor vertical farm. Seeds were sown in rockwool substrate, with A. brasilense (1.05 × 108 colony-forming units⋅L−1) or R. intraradices (580 propagules⋅L−1) applied weekly via subirrigation. Seedlings received chemical fertilizer, organic fertilizer derived from corn steep liquor and fermented fish by-products, and food waste-derived organic fertilizer at 100 ppm total nitrogen every 2 or 3 days. They were grown indoors at 23 °C under light-emitting diode lighting at a photosynthetic photon flux density of 200 μmol⋅m−2⋅s−1 with an 18-hour photoperiod. Lettuce under organic fertilizers had 75% lower shoot fresh mass and 64% less shoot dry mass compared with lettuce under chemical fertilizer. Similarly, tomato seedlings with organic fertilizers had fewer leaves, 75% less shoot fresh mass, and 67% less shoot dry mass. In both lettuce and tomato, the macronutrient and micronutrient concentrations in plant tissues were generally similar regardless of fertilizer treatments, but nitrogen use efficiency and nitrogen uptake efficiency were lower under organic fertilizers compared with those under chemical fertilizer. The inoculation of A. brasilense or R. intraradices showed limited effects on plant nutrient uptake, nutrient concentrations, and seedling growth in both lettuce and tomato. Further research is necessary to optimize application methods for organic fertilizers and beneficial microorganisms to fully harness the benefits of sustainable alternative fertilizers in soilless and hydroponic crop production.

Role of the molecular structure of humified organic matter in rice plant response to environmental lead pollution.

Humified organic matter has been shown to decrease Pb toxicity in plants. However, there are still gaps in our understanding of the mechanism by which this phenomenon occurs. In this study, we aimed to assess the ability of humic substances (HSs), humic acids (HAs), and fulvic acids (FAs) to enhance defense mechanisms in rice plants under lead (Pb)-stressed conditions. HS fractions were isolated from vermicompost using the chemical fractionation methodology established by the International Humic Substances Society. These fractions were characterized by solid-state NMR and FTIR. Chemometric analysis was used to compare humic structures and correlate them with bioactivity. Three treatments were tested to evaluate the protective effect of humic fractions on rice plants. The first experiment involved the application of humic fractions along with Pb. The second comprised pretreatment with humic fractions followed by subsequent exposure to Pb stress. The third experiment involved Pb stress and subsequent treatment with humic fractions. The root morphology and components of the antioxidative defense system were evaluated and quantified. The results showed that HS + Pb, HA + Pb, and FA + Pb treatment preserved root growth and reduced the levels of O2- and malondialdehyde (MDA) in the roots by up to 5% and 2%, respectively. Pretreatment of the plants with humic fractions promoted the maintenance of root growth and reduced the contents of O2-, H2O2, and MDA by up to 48%, 22%, and 20%, respectively. Combined application of humic fractions and Pb reduced the Pb content in plant tissues by up to 60%, while pretreatment reduced it by up to 80%. The protective capacity of humic fractions is related to the presence of peptides, lignin, and carbohydrate fragments in their molecular structures. These results suggest that products could be developed that can mitigate the adverse effects of heavy metals on agricultural crops.

Mechanism and ecological environmental risk assessment of peroxymonosulfate for the treatment of heavy metals in soil

Oxidation technologies based on peroxymonosulfate (PMS) have been effectively used for the remediation of soil organic pollutants due to their high efficiency. However, the effects of advanced PMS-based oxidation technologies on other soil pollutants, such as heavy metals, remain unknown. In this study, changes in the form of heavy metals in soil after using PMS and the risk of pollution to the ecological environment were investigated. Furthermore, two risk assessment methods, the mung bean germination toxicity test and groundwater leaching soil column test, were employed to evaluate the soil before and after PMS treatment. The results showed that PMS has a strong ability to degrade complex compounds, enabling the transformation of heavy metals, such as Cd, Pb, and Zn, from stable to active states in the soil. The risk assessments showed that PMS treatment activated heavy metals in the soil, which delayed the growth of plants, increased heavy metal content in plant tissues and the risk of groundwater pollution. These findings provide a new perspective for understanding the effects of PMS on soil, thus facilitating the sustained and reliable development of future research in the field of advanced oxidation applied to soil treatment.

Effect of biological sewage sludge and its derived biochar on accumulation of potentially toxic elements by corn (Zea mays L.)

The land application of sewage sludge can cause different environmental problems due to the high content of potentially toxic elements (PTEs). The objective of this study was to compare the effect of urban biological sewage sludge (i.e. the waste of activated sludge process) and its derived biochar as the soil amendments on the bioavailability of PTEs and their bioaccumulation by corn (Zea mays L.) under two months of greenhouse conditions. The soil was treated by adding biochar samples at 0 (control), 1, 3, 5% w/w. The diethylenetriamine pentaacetic acid (DTPA)-extractable concentrations of PTEs including Zn, Pb, Cd, Cr, Ni, Fe, and Cu in soil and their accumulation by plant shoot and root were measured. Conversion of the biological sewage sludge into the biochar led to decrease the PTEs bioavailability and consequently decreased their contents in plant tissues. The DTPA extractable metal concentrations of produced biochar in comparison to the biological sewage sludge reduced 75% (Cd), 65% (Cr), 79% (Ni and Pb), 76% (Zn), 91% (Cu) and 88% (Fe). Therefore, the content of Ni, Fe, Zn and Cd in corn shoot was decreased 61, 32, 18 and 17% respectively in application of 5% biochar than of raw sewage sludge. Furthermore, the application of 5% biochar enhanced the physiological parameters of the plants including shoot dry weight (twice) and wet weight (2.25 times), stem diameter (1.70 times), chlorophyll content (1.03 times) in comparison to using 5% raw sewage sludge. The results of the study highlight that application of the biochar derived from urban biological sewage sludge in soil could decrease the risk of PTEs to the plant.

Nutrient uptake efficiency and stoichiometry for different plant functional groups on spoil heap after hard coal mining in Upper Silesia, Poland

Various plant functional groups (PFGs) used in the reclamation of post-mining heaps may differ in their nutrient uptake efficiency and thus in their effect on the ecosystem development. The effect of PFGs may be additionally modified by the applied reclamation measures such as e.g. topsoiling. In this study we compared the nutrient uptake efficiencies and plant stoichiometry for two PFGs (grasses and forbs) growing on the sites reclaimed by applying topsoil (TS) and unreclaimed sites on carboniferous bare rock (BR) in hard coal spoil heap in Upper Silesia (southern Poland). Basic soil parameters, including pH, texture, soil organic carbon, and nutrients (N, P, K, Ca, and Mg), were measured, and the aboveground plant biomass and nutrient content in plant tissue were determined. Forbs were characterized by a larger biomass and higher nutrient concentrations (except for P) than grasses. The TS treatment supported higher concentrations of N and P in plant tissues but not to the level ensuring more significant primary biomass production. The nutrient concentration and elemental stoichiometry in plant tissue indicated that N was the primary limiting element. However, the major growth limitation for N-fixing forbs was from P. Forbs were much more efficient in nutrient uptake than grasses, independent of the reclamation treatment. Therefore, they stimulate nutrient cycling in the restored ecosystems more than grasses.

Organ-level distribution tandem mass spectrometry analysis of three structural types of brassinosteroids in rapeseed.

Brassinosteroids (BRs) are a class of naturally occurring steroidal phytohormones mediating a wide range of pivotal developmental and physiological functions throughout the plant's life cycle. Therefore, it is of great significance to determine the content and the distribution of BRs in plants.Regretfully, although a large number of quantitative methods for BRs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) have been reported, the in planta distribution of BRs is still unclear because of their lower contents in plant tissues and the lack of effective ionizable groups in their chemical structures. We stablished a novel analytical method of BRs based on C18 cartridge solid-phase extraction (SPE) purification, 4-(dimethylamino)-phenylboronic acid (DMAPBA) derivatization, and online valve-switching system coupled with ultra-high performance liquid chromatography-electro spray ionization-triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS). This method has been used to quantify three structural types of BRs (epibrassinolide, epicastasterone, and 6-deoxo-24-epicastaster one) in different organs of Brassica napus L. (rapeseed). We obtained the contents of three structural types of BRs in various organ tissues of rapeseed. The contents of three BRs in rapeseed flowers were the highest, followed by tender pods. The levels of three BRs all decreased during the maturation of the organs. We outlined the spatial distribution maps of three BRs in rapeseed based on these results, so as to understand the spatial distribution of BRs at the visual level. Our results provided useful information for the precise in situ localization of BRs in plants and the metabolomic research of BRs in future work. The in planta spatial distribution of BRs at the visual level has been studied for the first time.

Effect of brassinosteroids on rooting of the ornamental deciduous shrubs

Brassinosteroids are a developing group of growth regulators. They are a group of steroid hormones involved in plants’ physiological and developmental processes. Among other things, they are responsible for cell wall regeneration or cell elongation. This experiment aimed to examine the effect of rooting stimulants on rhizogenesis in cuttings of two deciduous shrub species: Philadelphus ’Virginal’ and Hydrangea paniculata ’Limelight’. Aqueous solutions of indole-3-butyric acid (IBA) at 200 mg·L–1, Brassinolide (BL) at 0.05% and 24-epibrassinolide (24epiBL) (0.05%) were used in this study. The results obtained showed that both auxin and both of the brassinosteroids used increased the percentage of rooted cuttings almost twice, the degree of rooted cuttings and root length – for BL + IBA – longer roots than the control by 41% in jasmine and by 59% in hydrangea. The growth regulators applied during the rooting of cuttings also caused changes in the organic compound content of plant tissues and the activity of oxidative stress enzymes. The studies and results suggest that brassinosteroids may soon replace the popular rooting stimulants.

Exploring the Impact of Endophytic Fungus Aspergillus cejpii DMKU-R3G3 on Rice: Plant Growth Promotion and Molecular Insights through Proteomic Analysis

Rice is a crucial crop for many people worldwide, especially in regions like Asia, Latin America, and parts of Africa. Thailand is one of the largest exporters of rice. Nowadays, farmers use chemicals to control rice disease, which can have negative effects on humans and the environment. Therefore, the objective of this study was to examine the plant-promoting capabilities of the endophytic fungal strains DMKU-R3G3 in greenhouse settings. The endophytic fungi strain DMKU-R3G3, which was isolated from organic rice root, was identified as Aspergillus cejpii based on morphological characteristics and phylogenetic analysis. The production of IAA was detected using Salkowski’s reagent. After 7 days of incubation, the finding revealed that the strain cultivated in PDB supplemented with tryptophan yielded a greater concentration of IAA (25.45 μg/mL). The inoculation with A. cejpii DMKU-R3G3 significantly enhanced rice growth, as evidenced by notable increases in shoot height, root length, and fresh weight. Moreover, the chlorophyll content of the rice plants also increased by 1.78 times more than the control group. In addition, proteomic analysis revealed that rice responded toward the colonization of endophytic fungi by producing auxin-responsive proteins to regulate the IAA content in plant tissue and inducing total chlorophyll production due to the up-regulation of proteins in the chlorophyll biosynthesis pathway. The results obtained from this study lead to the conclusion that the A. cejpii strain DMKU-R3G3 possesses the capability to enhance plant growth through the production of phytohormones in greenhouse conditions. Therefore, endophytic A. cejpii DMKU-R3G3 has the potential to be a promising eco-friendly plant growth promoter for sustainable rice cultivation.

Sheep manure and sewage sludge boost biofortification of barley and restricts heavy metal accumulation in plant tissues

In recent centuries, micronutrient deficiencies are considered a major challenge for human health. Biofortification of principal crops has been broadly accepted as a sustainable scenario to overcome this limitation. The experiment was carried out in a completely randomized factorial design with three replications during the 2007–2008 and 2008–2009 growing seasons. Four fertilizers and two doses of humic acid were used in the experiment. Analysis of variance indicated that humic acid, fertilizer type, and growing season caused statistically significant differences in macro and micronutrient content and heavy metal concentrations of shoot and seed in plants. Results also denoted that organic material amendment improved macro and micronutrient content of barley plants compared with IF in which SS treatment increased Ca, Mg, Mn, Fe, Zn, and Ni concentrations in shoot/seed while SM treatment enhanced N, P, and K concentration of plants. Moreover, IF-treated plants increased heavy metal accumulation in shoot and seed tissues whereas organic amendments reduced heavy metal uptake such that the lowest Pb and Cd were determined in SM-treated plants, and the lowest Ni content was measured in W-treated samples. HA application promoted Zn, Mg, and Cu accumulation in plants, however, individual or combined with fertilizers reduced other micro and macronutrient uptake. In conclusion, the amendment of 40 tons ha−1 of sheep manure and sewage sludge is an improving and beneficial practice in barley cultivation for the biofortification of crops. However, HA treatment did not form a meaningful whole in the experiment but promoted Zn, Mg, and Cu concentrations in plant tissues.

Assessment of Air Pollution in Ulaanbaatar Using the Moss Bag Technique.

Active moss biomonitoring, the so-called moss bag technique, widely applied in many countries, for the first time, was applied to assess the air quality in Ulaanbaatar (Mongolia). Moss bags with Sphagnum girgensohnii Russow were exposed in triplicate in three different periods: December-February, March-May, and December-May at 13 governmental air quality monitoring stations located in the vicinity of thermal power plants and residential areas. The plant tissue content of Al, Ba, Co, Cd, Cr, Cu, Fe, Mn, P, Pb, Sr, S, V, As, and Zn was determined using inductively coupled plasma-optical emission spectrometry, and a direct mercury analyzer was used to determine the Hg content. The samples in residential areas and near thermal power plants that were exposed for 3months in winter and for 6months (winter to spring) were characterized by the highest accumulation of the elements. In the moss bags exposed during spring, maximum accumulation of the determined elements was noted in residential areas and near main roads. Regardless of the exposure time and duration, the highest accumulation of Al, Fe, and V was determined at Dambadarjaa air quality station located near a highway and of Hg near the Amgalan power plant. Significant differences in element accumulation between seasons were observed, thus, the accumulation of Al, Ba, As, Co, Cr, Fe, Pb, V, and Zn was higher in spring, while P and S had higher content in the moss samples exposed during winter. The accumulation of elements over the 6-month exposure period was 1.1-6.7 times higher than that of the 3-month periods. Thus, the 6-month exposure can be considered a reliable deployment period as it ensures an adequate signal in terms of enrichment of pollutants. Factor analysis was applied to highlight the association of elements and to link them with possible sources of emission. Three factors were determined, the first one included Al, As, Ba, Co, Cr, Fe, Mn, Pb, Sr, and V and was identified as a geogenic-anthropogenic, the second (Cu, P, and S) and third (Cd and Zn) factors suggested anthropogenic origin. The Relative accumulation factor and enrichment factor were calculated to evaluate the level of air pollution and possible element sources. Considerable contributors to air pollution were Zn, Fe, As, V, Cr, and Al, which may originate from airborne soil particles of crustal matter or transport, as well as coal combustion for heating and cooking.

Combining mid-infrared spectroscopy and machine learning to estimate nutrient content in plant tissues of yerba mate (Ilex paraguariensis A. St. Hil.)

Mid-infrared diffuse reflectance spectroscopy with machine learning methods has been studied worldwide for estimating nutrient content in plant tissue of numerous plant species. Therefore, this study aimed to evaluate the best combination of spectral preprocessing and machine learning methods for estimating the concentration of chemical elements in leaf tissues of Ilex paraguariensis. From 2019 to 2021, 111 samples were collected from farms throughout Rio Grande do Sul State in southern Brazil. The total concentration of 11 nutrients (N, P, K, Ca, Mg, B, S, Mn, Fe, Cu, and Zn) and the spectra recorded in the mid-infrared range (2500– 18,000 nm) were obtained. The original spectrum underwent detrending, standard normal variate, and Savitzky-Golay derivative (SGD) spectral preprocessing. Multivariate partial least squares regression and support vector machine models were used to calibrate the spectra based on the nutrient concentrations obtained from the conventional analytical method. The models’ performance was evaluated using the coefficient of determination, the ratio of performance to the interquartile range, and the root mean square error of prediction. The support vector machine model combined with SGD preprocessing resulted in a more accurate prediction of the 11 elements studied in leaf tissue samples.

Nitrate fertilization enhances manganese phytoextraction in Tanzania guinea grass: a novel hyperaccumulator plant?

Manganese (Mn) is essential for plants but very toxic at high rates. However, hyperaccumulators can tolerate high Mn concentrations in plant tissue, especially when properly fertilized with N. Tanzania guinea grass (Megathyrsus maximus Jacq.) has been indicated as metal tolerant and a good candidate for Mn phytoextraction due to its fast growth and high biomass. The objective was to evaluate the Mn hyperaccumulator potential of Tanzania guinea grass grown as affected by proportions of nitrate/ammonium (NO3-/NH4+). An experiment in a growth chamber with nutrient solution, combining NO3-/NH4+ proportions (100/0 and 70/30) and Mn rates (10, 500, 1500, and 3000 μmol L-1), was carried out. The highest Mn concentration was verified in plants grown with 100/0 NO3-/NH4+ and Mn at 3000 μmol L-1, reaching up to 5500 and 21,187 mg kg-1 in shoots and roots, respectively, an overall concentration of 13,345 mg kg-1. These numbers are typically seen in hyperaccumulators. At that combination, Mn accumulation in shoots was also the highest, reaching up to 76.2 mg per pot, a phytoextraction rate of 23.1%. Excess Mn increased both H2O2 concentration in roots and non-photochemical quenching and therefore decreased net photosynthesis, stomatal conductance, electron transport rate, and photochemical quenching. Nevertheless, proline concentration in roots affected by excess Mn was high and indicates its important role for mitigating stress since Mn rates did not even affect the dry biomass. Tanzania guinea grass is highly tolerant to excess Mn as much as a hyperaccumulator. However, to show all its potential, the grass needs to be supplied with N as NO3-. We indicate Tanzania guinea grass as a Mn hyperaccumulator plant.

Selenite (IV) and selenate (VI) uptake and accumulation capacity of Lemna minor L. from an aquatic medium

ABSTRACT The uptake of sodium selenite (Se(IV)) and sodium selenate (Se(VI)) from aqueous medium by Lemna minor L. and the influence of different Se concentrations on its growth, morphological and ultrastructural characteristics were studied. L. minor was grown at different concentrations (1, 3, 5 and 10 mg L−1) of Se(IV) and Se(IV). The Se(IV) concentration in the plant tissue ranged between 77.7 (± 4.3) to 453 (± 0) mg kg−1 DW. The Se(VI) concentration in plant tissues ranged between 117 (± 11) to 417 (± 2) mg kg−1 DW. The highest bioconcentration factor for Se(VI) was 127 (± 7) at 3 mg/L, with a Se removal efficiency of 44%. For Se(IV), the highest bioconcentration factor was 77.7 (± 4.3) at 1 mg L−1, which had a Se removal efficiency of 23%. Growth of L. minor was suppressed at 10 mg L−1 Se in both forms. The addition of Se promoted the formation of starch granules in L. minor which occupied a chloroplast area of 74% for Se(IV) and 77% for Se(VI). The efficient uptake of both Se forms by L. minor indicates the potential application of this species for phytoremediation of Se laden wastewaters and its use as an alternative feedstock in biofuel production.

ДЕСТРУКЦИЯ ФИТОГОРМОНОВ БАКТЕРИЯМИ-СТИМУЛЯТОРАМИ РОСТА РАСТЕНИЙ

Phytohormones serve as regulators of plant growth and development, playing a fundamental role in the adaptation and survival of plants under different conditions. It is well-known that bacteria have the ability to influence plant physiology by producing phytohormones or decreasing their concentration in plant tissues and the surrounding environment through degradation or transformation. Studying these processes is crucial for a deeper comprehension of plant-microorganism interactions. This study presents the capability of bacteria that promote plant growth and development to degrade phytohormones (ABA, 6-BAP, and IAA) in a culture medium using them as the sole carbon and energy source. It was discovered that a significant portion of the selected strains could thrive on a medium containing ABA, 6-BAP, and IAA. However, the growth intensity varied significantly among different substrates. For instance, strains Pseudomonas plecoglossicida 2,4-D (2,4-D), Pseudomonas sp. RZ (RZ), and Pseudomonas plecoglossicida CH5%2 (CH5%2) exhibited equal growth rates on all substrates, but high-performance liquid chromatography (HPLC) results indicated that strain 2,4 D was the most efficient in the degradation of the aforementioned phytohormones. The extent of biodegradation of ABA, 6-BAP, and IAA by this strain during a 10-day cultivation period amounted to 33%, 70%, and 60%, respectively.