Aboveground Plant Parts Research Articles

Phytoextraction potential of herbaceous plant species and the influence of environmental factors – A meta-analytical approach

Heavy metals account for a notable share of soil and water body contaminations. For restoring contaminated soils, phytoremediation is considered an eco-friendly and sustainable practice. However, the implementation in the field requires a well-thought-out plant selection and comprehensive knowledge of the influence of various environmental factors. Therefore, a quantitative evaluation of 330 studies was done using a meta-analytical approach. The systematic assessment included the calculation of bioconcentration factors for roots and shoots (BCFROOT, BCFSHOOT) and translocation factors (TF) of 48 herbaceous species, as well as the identification of the most important soil and plant factors that regulate the heavy metal uptake into plant tissues. The results showed substantial variations in roots' and shoots' heavy metal uptake capacity among the diverse plant species. The uptake also varied depending on the type of heavy metal. Most species revealed a higher accumulation of heavy metals in roots than shoots, indicating a limited heavy metal transport from below-ground into above-ground plant parts. Among the different heavy metals, Cd showed the highest median BCFSHOOT and BCFROOT, followed by Zn, Cu, Ni, Cr, and Pb, which can partly be explained by the solubility and plant availability of the elements. The strongest significant and positive correlations of heavy metal contents in plant tissues were found with the total and available soil content. Clay and silt content showed a weak negative, and sand content a slight positive correlation. Further, root, shoot and total biomass revealed weak negative correlations to the plants' heavy metal contents. Overall, this study forms a basis for the minimum accumulation capacities of various species and thus makes an essential contribution to the planning and practical application of phytoremediation projects.

Draft genome sequences of eight bacterial isolates from Pisum sativum leaf surfaces.

Bacterial communities in the phyllosphere, the above-ground parts of plants, are diverse yet understudied. These bacteria are important for plant health and also for inter-kingdom interactions with beneficial and pest insect species. Here, we present draft genomes of eight culturable bacterial isolates from leaf surfaces in the Pisum sativum phyllosphere.

The content of amino acids in tomato plants when using the preparations “Monosodium Glutamate” and “Aminozol” in conditions of salt stress

Relevance. The study of the effect of preparations containing amino acids on the accumulation of free amino acids in plants is relevant in assessing their regulatory and anti-stress effects.Methods. A laboratory experiment was carried out in 2020 on tomato plants of the Betta variety. Gray forest medium loamy soil was used as a substrate. The experiment was performed on soil with different salinity — a) control (the soil is not saline), b) saline soil (50 mmol/kg NaCl), c) saline soil (100 mmol/kg NaCl), using three feeding options: without top dressing, top dressing with “Sodium Glutamate”, top dressing with “Aminozol”. Amino acids were extracted from the roots and aboveground parts of plants in the vegetative growth phase with a mixture of “ethanol + chloroform + water” (12:5:2) and the method of high-performance liquid chromatography (HPLC) with pre-columnar derivatization of amino acids with phenylisothiocyanate was used. Results. Soil salinization with sodium chloride caused an increase in the amount of free amino acids in tomato seedlings. The total amino acid content increased to 849.8 µg/kg (50 mmol/kg NaCl) and 606.9 µg/kg (100 mmol/kg NaCl) compared to the control soil (385.3 µg/kg). Salinity contributed to the accumulation of serine (from 50.4 to 414.4 µg/kg) in seedlings. Treatment with preparations (“Monosodium glutamate” and “Aminozol”) affected the accumulation of a number of amino acids responsible for plant stress resistance. Supplementation with monosodium glutamate increased the total amino acid concentration to 1146.6 µg/kg (50 mmol/kg NaCl) and 1017.7 µg/kg (100 mmol/kg NaCl) compared to the corresponding variants without supplementation. At the same time, the content of glutamic (up to 188.3 and 425.1 µg/kg) and aspartic (up to 50.8 and 198.7 µg/kg) acids increased. “Aminosol” contributed to an increase in the amount of amino acids to 1834.2 µg/kg (50 mmol/kg NaCl) and 934.4 µg/kg (100 mmol/kg NaCl), respectively.

Исследование интегральной токсичности почвы, загрязнённой нефтепродуктами

The effect of contamination with technical waste oil on the integral toxicity of sod-podzolic sandy loam soil under field experiment conditions was studied. The integral toxicity of the soil aqueous extract was determined using the «Ecolum» bacterial test, which is a luminescent gene-engineered Escherichia coli. Control soil samples show acceptable levels of toxicity. Soils contaminated with 10 or 20 g/kg doses of petroleum products are moderately toxic. The dose of 30 g/kg makes the soil highly toxic for luminescent microorganisms. The hydrocarbon composition of technical waste oil was determined using spectral coefficients obtained by infrared spectrometry. High content – 6.73% – of aromatic hydrocarbons (the most toxic fraction) was revealed. Correlation analysis between the soil toxicity index, the content of oil products, heavy metals (Co, Ni, Cu, Zn, Pb) and the pH of the soil aqueous extract showed a very strong positive correlation between toxicity and zinc content (r = 0.88) and oil products content (r = 0.83) in the soil, as well as a high negative correlation on soil pH (r = –0.61). The phytomass of plants growing on contaminated sites was determined. A very high inverse correlation (r = –0.82) between the content of oil hydrocarbons in the soil and phytomass confirms that soil contamination with an increased dose of oil products reduces the biomass of the aboveground part of plants. A general tendency to displacement of monocots and their replacement by dicots was observed for polluted soils.

No Pairwise Interactions of GmSNAP18, GmSHMT08 and AtPR1 with Suppressed AtPR1 Expression Enhance the Susceptibility of Arabidopsis to Beet Cyst Nematode.

GmSNAP18 and GmSHMT08 are two major genes conferring soybean cyst nematode (SCN) resistance in soybean. Overexpression of either of these two soybean genes would enhance the susceptibility of Arabidopsis to beet cyst nematode (BCN), while overexpression of either of their corresponding orthologs in Arabidopsis, AtSNAP2 and AtSHMT4, would suppress it. However, the mechanism by which these two pairs of orthologous genes boost or inhibit BCN susceptibility of Arabidopsis still remains elusive. In this study, Arabidopsis with simultaneously overexpressed GmSNAP18 and GmSHMT0 suppressed the growth of underground as well as above-ground parts of plants. Furthermore, Arabidopsis that simultaneously overexpressed GmSNAP18 and GmSHMT08 substantially stimulated BCN susceptibility and remarkably suppressed expression of AtPR1 in the salicylic acid signaling pathway. However, simultaneous overexpression of GmSNAP18 and GmSHMT08 did not impact the expression of AtJAR1 and AtHEL1 in the jasmonic acid and ethylene signaling pathways. GmSNAP18, GmSHMT08, and a pathogenesis-related (PR) protein, GmPR08-Bet VI, in soybean, and AtSNAP2, AtSHMT4, and AtPR1 in Arabidopsis could interact pair-wisely for mediating SCN and BCN resistance in soybean and Arabidopsis, respectively. Both AtSNAP2 and AtPR1 were localized on the plasma membrane, and AtSHMT4 was localized both on the plasma membrane and in the nucleus of cells. Nevertheless, after interactions, AtSNAP2 and AtPR1 could partially translocate into the cell nucleus. GmSNAP18 interacted with AtSHMT4, and GmSHMT4 interacted with AtSNAP2. However, neither GmSNAP18 nor GmSHMT08 interacted with AtPR1. Thus, no pairwise interactions among α-SNAPs, SHMTs, and AtPR1 occurred in Arabidopsis overexpressing either GmSNAP18 or GmSHMT08, or both of them. Transgenic Arabidopsis overexpressing either GmSNAP18 or GmSHMT08 substantially suppressed AtPR1 expression, while transgenic Arabidopsis overexpressing either AtSNAP2 or AtSHMT4 remarkably enhanced it. Taken together, no pairwise interactions of GmSNAP18, GmSHMT08, and AtPR1 with suppressed expression of AtPR1 enhanced BCN susceptibility in Arabidopsis. This study may provide a clue that nematode-resistant or -susceptible functions of plant genes likely depend on both hosts and nematode species.

The Use of Hydrogen Peroxide and Silver Nanoparticles in Horticulture

Abstract Both hydrogen peroxide and silver can oxidize organic and inorganic molecules, and this causes them to affect the metabolism of living organisms in many ways. The paper presents examples of the impact of H2O2 and silver on stimulating plant growth and development and increasing plants’ resistance to biotic and abiotic stresses. The most underlined proposal for application in horticulture is the control of microorganisms during cultivating and storing vegetables, fruits, and flowers, aiming to replace synthetic pesticides. Preparations containing H2O2, silver, or both components can be widely used in horticulture for plant protection, in the form of spraying and soaking seedlings, to protect them during the time of storage, for disinfecting tubers, bulbs, and rhizomes before planting, for fogging potatoes and root vegetables during storage, for quick healing of wounds on the roots and aboveground parts of plants, after cutting and in the case of frost damage and injuries caused by winds, for disinfecting seeds, and, as stimulants of plant development and inducers of resistance to biotic and abiotic stresses. However, their practical use depends on obtaining the legislator’s consent for their broader use in horticultural production.

Artificial Light at Night (ALAN) Influences Understory Plant Traits through Ecological Processes: A Two-Year Experiment in a Rubber Plantation in China

Artificial light at night (ALAN) demonstrated a new ecological factor that influences organisms through a multi-approach. Yet, the impacts of ALAN on understory plants remain largely unknown. We evaluated whether ALAN would affect the leaf mass per area (LMA) of understory plants through a two-year field light experiment in a tropical rubber plantation in south China. We hypothesized that ALAN could impact the understory in two ways: by directly supplementing light to aboveground plant parts (which increases LMA) and indirectly affecting soil nutrient composition by attracting insects (which decreases LMA). We selected two species: Colocasia gigantea, representing shade-tolerant species, and Melastoma candidum, representing light-demanding species. We measured canopy openness, LMA, soil nutrients, and individual distance away from light resources. Our Bayesian linear mixed model showed a negative relationship between LMA and the strength of ALAN, indicating that ALAN may influence LMA more indirectly by enhancing soil nutrient availability rather than directly acting as a light resource. This relationship was significant for Colocasia gigantea but not for Melastoma candidum. These results suggest that ALAN might have complex and species-specific impacts on the understory ecosystem. Our study underscores the need for continued research and informed management of anthropogenic ecosystems.

Phytochemical and biological investigations on Centranthus kellereri (Stoj., Stef. & T. Georgiev) Stoj. & Stef. and C. ruber (L.) DC. and their potential as new medicinal and ornamental plants.

Centranthus kellereri is a Bulgarian endemic plant species, found only in two locations in the world: The Balkans Mountains (Stara Planina), above the town of Vratsa, and The Pirin Mountains, above the town of Bansko, Bulgaria. Being endemic and endangered species precluded any significant research on it. The hypothesis of this study was that the populations of C. kellereri may represent genetically, phytochemically, and morphologically distinct forms and these will differentiate from C. ruber. Furthermore, C. kellereri possibly imperfect embryology may preclude its more widespread distribution under natural conditions. This study revealed the phytochemical profile, antioxidant activity, embryology, surface microstructural morphological traits, and genetic differences between the C. kellereri plants from the only two natural populations and compares them to the ones of the related and better-known plant C. ruber. The essential oil (EO) content in aboveground plant parts and in roots was generally low and the EO composition varied significantly as a function of plant part, year of sampling, location, and species. Methylvaleric acid was a major EO constituent in the C. kellereri EO, ranging between 60.2% and 71.7% of the total EO. The EO included monoterpenes, sequiterpenes, long-chain alkanes and fatty acids. Phytochemical analyses of plant tissue revealed the occurrence of 32 compounds that were tentatively identified as 6 simple phenolics, 18 flavonoids, 1 quinone, 1 lipid, 1 alkaloid, 2 diterpenes, and 3 triterpenes. There were differences in detected compounds between the C. kellereri plants at the two locations and between the roots and shoots in both species. The total phenols and flavonoids varied between the two species but were also dissimilar between the plants from the two populations of C. kelleri. Free radical scavenging activity, measured with ABTS and DPPH in aqueous and methanol extracts, had similar values; however, overall, C. kellereri from Vratsa showed the highest antioxidant activity while C. ruber had the lowest activity. Genetic analyses showed a clear differentiation between C. kellereri and C. ruber, and between the two populations of C. kellereri. Embryological studies revealed the peculiarities of the male and female generative spheres of the two species that were defined as being sexually reproducing. The pollen had high viability; however, the low viability of seeds demonstrated possible high sensitivity of C. kellereri to the environmental conditions, perhaps the main factor modifying and restricting the population sizes. The SEM analyses exposed differences in surface microstructural traits between the species (C. kellereri and C. ruber) but also between the two populations of C. kellereri. The observed dissimilarities in genetic makeup, micromorphological characteristics, and phytochemical composition strongly indicate that the two populations can be classified as distinct subspecies or varieties of C. kellereri; var. pirinensis and var. balkanensis. Further research is needed to introduce C. kellereri into culture and develop it as a high-value specialty crop or ornamental in order to conserve C. kellereri natural populations. C. kellereri may be utilized as a source for phytochemicals of interest and as an ornamental plant like C. ruber; however, it may have a greater environmental plasticity and adaptation as evidenced by its current locations.

Unveiling the complexity of strigolactones: exploring structural diversity, biosynthesis pathways, and signaling mechanisms.

Strigolactone is the collective name for compounds containing a butenolide as a part of their structure, first discovered as compounds that induce seed germination of root parasitic plants. They were later found to be rhizosphere signaling molecules that induce hyphal branching of arbuscular mycorrhizal fungi, and, finally, they emerged as a class of plant hormones. Strigolactones are found in root exudates, where they display a great variability in their chemical structure. Their structure varies among plant species, and multiple strigolactones can exist in one species. Over 30 strigolactones have been identified, yet the chemical structure of the strigolactone that functions as an endogenous hormone and is found in the above-ground parts of plants remains unknown. We discuss our current knowledge of the synthetic pathways of diverse strigolactones and their regulation, as well as recent progress in identifying strigolactones as plant hormones. Strigolactone is perceived by the DWARF14 (D14), receptor, an α/β hydrolase which originated by gene duplication of KARRIKIN INSENSITIVE 2 (KAI2). D14 and KAI2 signaling pathways are partially overlapping paralogous pathways. Progress in understanding the signaling mechanisms mediated by two α/β hydrolase receptors as well as remaining challenges in the field of strigolactone research are reviewed.

The genome of the toxic invasive species Heracleum sosnowskyi carries an increased number of genes despite absence of recent whole-genome duplications.

Heracleum sosnowskyi, belonging to a group of giant hogweeds, is a plant with large effects on ecosystems and human health. It is an invasive species that contributes to the deterioration of grassland ecosystems. The ability of H. sosnowskyi to produce linear furanocoumarins (FCs), photosensitizing compounds, makes it very dangerous. At the same time, linear FCs are compounds with high pharmaceutical value used in skin disease therapies. Despite this high importance, it has not been the focus of genetic and genomic studies. Here, we report a chromosome-scale assembly of Sosnowsky's hogweed genome. Genomic analysis revealed an unusually high number of genes (55106) in the hogweed genome, in contrast to the 25-35 thousand found in most plants. However, we did not find any traces of recent whole-genome duplications not shared with its confamiliar, Daucus carota (carrot), which has approximately thirty thousand genes. The analysis of the genomic proximity of duplicated genes indicates on tandem duplications as a main reason for this increase. We performed a genome-wide search of the genes of the FC biosynthesis pathway and surveyed their expression in aboveground plant parts. Using a combination of expression data and phylogenetic analysis, we found candidate genes for psoralen synthase and experimentally showed the activity of one of them using a heterologous yeast expression system. These findings expand our knowledge on the evolution of gene space in plants and lay a foundation for further analysis of hogweed as an invasive plant and as a source of FCs.

Interaction of chromium (Cr) resistant plant growth promoting rhizobacteria with compost to phytostabilize Cr in spinach rhizosphere

Chromium (Cr) is classified as an ecological toxin, and irrigation of soil with raw industrial effluents causes its concentration in soil and plants to reach fatal levels. Due to reduced metal mobility caused by organic amendment and availability of food for microbial activity, use of Cr-tolerant rhizobacteria in conjunction with compost has proven to be useful in supporting growth and survival of plants. We checked the simultaneous effects of rhizobacteria and compost on spinach (Spinacia oleracea) growth, physiology, biochemistry as well as uptake of Cr. Plants were treated with compost (1 % w/w) and subsequently inoculated with two different PGPR strains under Cr contamination. Among tested inoculants , inoculation of 'JS2′ strain along with compost significantly ameliorated the adverse effects of Cr on spinach, and improved root and shoot lengths (84 and 197 %), as well as their dry (104 and 89 %) and fresh (89 and 167 %) weights , along with chlorophyll content (84 %) as compared to relative control. In addition, combined application led to a significant increase in antioxidant activities, such as SOD (128 %), CAT (40 %), POD (73 %) and APX (57 %) concomitant with decreased MDA contents (68 %). Data regarding Cr movement from soil to roots and aboveground plant parts, as well as the results of translocation and bioconcentration factors, revealed that combined application of PGPR and compost reduced Cr entry to aboveground plant parts and led to its phytostabilization. Hence, compost and Cr-tolerant PGPR can efficiently immobilize Cr in soil, and reduce its harmful effects on spinach growth, physiology and other important attributes.

Mesquite-associated soil and phyllosphere microbial communities differ across land-use types in drylands

Plant-associated microbiomes play prominent roles in maintaining plant health and productivity. Here, we characterized the soil and phyllosphere microbiomes associated with mesquite trees in grazing and urban areas compared to natural areas in the arid Southwestern United States. Our results showed that grazing areas were associated with higher phyllosphere fungal richness, while urban areas had higher phyllosphere richness for both fungi and bacteria/archaea, and additionally, urban soils had lower fungal richness. Specifically, grazing areas were characterized by larger proportions of nitrogen-fixing bacteria in the soil and fungal plant pathogens in the phyllosphere, while urban areas presented higher proportions of fungal plant pathogens in both the soil and phyllosphere as well as nitrifying and denitrifying bacteria in the phyllosphere, but a lower proportion of cellulolytic bacteria in the soil. Furthermore, in urban areas, more phyllosphere microorganisms were sourced from the soil. Collectively, these results suggest that plant-associated microbiomes change significantly across land-use types, and these patterns are different between aboveground and belowground parts of plants, as well as between bacteria/archaea and fungi. These changes in plant-associated microbiomes across land-use types might have important implications for nutrient cycling, plant health, and ecosystem restoration.

Total Content of Saponins, Phenols and Flavonoids and Antioxidant and Antimicrobial Activity of In Vitro Culture of Allochrusa gypsophiloides (Regel) Schischk Compared to Wild Plants.

Allochrusa gypsophiloides is a rare Central Asian species, a super-producer of triterpene saponins with pharmacological and technical value. In this work, a comparative evaluation of the in vitro culture of adventitious roots (ARs), in vitro adventitious microshoots (ASs), natural roots and aboveground parts of wild plants from Kazakhstan to define the total saponin (TS), phenol (TP) and flavonoid (TF) content, as well as antioxidant (AOA) and antimicrobial activity, is presented for the first time. In the AR culture, growth index (GI), TS, TP and TF were evaluated on days 25, 45 and 60 of cultivation on ½ MS medium without (control) and with auxin application. It was found out that TS and TF were higher in the in vitro AR culture. The amount of TP and TF are higher in the aerial part of vegetative plants with maximum AOA. The concentration of the extract required to inhibit 50% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical formation (ICO50) in extracts from natural material negatively correlated with TS, TP, TF and in the in vitro AR culture with TF. Control extracts from the in vitro AR culture with high TS levels showed growth-inhibitory activity against S. thermophillus, S. cerevisiae and C. albicans. The influence shares of medium composition factor, cultivation duration factor and their interaction with GI, TS, TP and TF were determined. The in vitro AR culture is promising for obtaining triterpene saponins TSR with high antibacterial and antifungal activity, and the in vitro ASs culture-for shoot multiplication with antioxidant properties.

Garbage to Gains: The role of biochar in sustainable soil quality improvement, arsenic remediation, and crop yield enhancement

Threats of soil quality deterioration and metal pollution have inflicted several parts of the world, apart from the need for surplus crop production. The investigation used biochar prepared from waste biomasses such as wheat and rice straw, kitchen waste, leaf litter, Lantana camara, orange peel, and walnut shell to improve soil quality, reduce As pollution, and enhance plant growth. Biochars were amended at doses of 0%, 2.5%, 5%, and 7.5% and conditioned for 3 months. At a 7.5% dose, the maximum improvements in cation exchange capacity (a 62% increase), anion exchange capacity (a two-fold increase), bulk density (a 31% decrease), porosity (a 32% increase), water holding capacity (an 86% increase), soil respiration (a 32% increase), total carbon (a two-and-a-half-fold increase), total nitrogen (an eleven-fold increase), total phosphorus (3 times rise), total potassium (a two-and-a-half-fold increase), mobile As (a 38% decrease), leachable As (a 53% decrease), and bio-available As (a 56% decrease) were observed. Further, pot experiments revealed augmented biomass growth (61% and 177%), increased length (71% and 209%), and decreased As accumulation (56% and 55%) in the above-ground parts of Bengal gram and coriander plants, respectively. Therefore, the application of biochar was found to enhance the physico-chemical properties of soil, reduce As contamination levels, and improve crop growth. The study recommends using waste biomasses to prepare eco-friendly biochars, which could contribute to advancing sustainable agriculture and the circular economy.

A dataset of the litterfall recovery amount and the standing crop dynamics in the tropical seasonal rainforests of Xishuangbanna (2005–2020)

Litterfall refers to the collective organic matter generated by the aboveground parts of plants that accumulates on the surface. It is a key medium linking the ecological processes between the aboveground and the underground in terrestrial ecosystems. Litterfall recovery and the standing crop comprise the dry weight of branches, leaves, flowers and fruits, bark, moss and lichen, and so on. The annual yield of leaf litterfall can provide data support for the assessment of forest productivity, and the falling flowers and fruits are of great value to the research of forest seed rain. The proportion of each component is an important factor affecting nutrient cycling and carbon cycling in the ecosystem. The dataset collects the litterfall recovery amount and the standing crop of the tropical seasonal rainforest in Xishuangbanna during 2005–2020. The establishment and sharing of this dataset can furnish fundamental data for the in-depth examination of vegetation structure and ecosystem function under the global hydrothermal pattern changes, and serve as a foundation for advancing the study of the litterfall and tropical seasonal rain forests.

Phyllosphere 2022: 11th International Symposium on Leaf Surface Microbiology

This Meeting Review article offers a synthesis of the science presented and discussed at the recently held 11th International Symposium on Leaf Surface Microbiology, also known as Phyllosphere 2022, at the University of California–Davis (UC Davis), 17 to 21 July 2022. Twice postponed due to Covid-19, this in-person conference covered wide-ranging but intersecting topics related to the microbiology of leaves (and other aboveground parts of plants), including phytopathology, food safety, plant physiology, microbial ecology, fluid physics, vegetation science, single-cell biology, canopy architecture, and human health. The overarching theme of the meeting (“understanding the rules of phyllospheric life”) was explored in 46 podium and 12 poster presentations. It also fueled the formal and informal discussions among 90-plus conference participants about existing and new questions in phyllosphere microbiology. Are there first principles underlying the acquisition, assembly and succession of microbial communities in the phyllosphere? How best to define, recognize, and exploit phyllosphere fitness of microscopic leaf dwellers? At what scales do or should we sample, interrogate, and understand the phyllosphere? What still needs to be learned that keeps us from new insights, resources, and tools to produce healthier or more nutritious plant foliage? Having the conference at UC Davis in the summer presented a unique opportunity to “vertically integrate” high school students from the COSMOS program into the Phyllosphere 2022 conference and allow face-to-face interactions with early-career scientists and prominent senior career professionals in phyllosphere microbiology. Students thus experienced first-hand the ways in which scientists address problems that affect society and seek understanding and solutions to those problems. It represented an effective approach to engage a younger generation into thinking about research and stewardship of plants and their foliage and, more generally, about the merits of a science career.

The Roles of Hormone Signals Involved in Rhizosphere Pressure Response Induce Corm Expansion in Sagittaria trifolia.

Soil is the base for conventional plant growth. The rhizosphere pressure generated from soil compaction shows a dual effect on plant growth in agricultural production. Compacted soil leads to root growth stagnation and causes bending or thickening, thus affecting the growth of aboveground parts of plants. In arrowhead (Sagittaria trifolia L.), the corms derived from the expanded tips of underground stolons are its storage organ. We found that the formation of corms was significantly delayed under hydroponic conditions without rhizosphere pressure originating from soil/sand. In the initial stage of corm expansion, the anatomic structure of arrowhead corm-forming parts harvested from hydroponics and sand culture was observed, and we found that the corm expansion was derived from cell enlargement and starch accumulation. Comparative transcriptome analysis indicated that the corm expansion was closely related to the change in endogenous hormone levels. Endogenous abscisic acid and salicylic acid concentrations were significantly increased in sand-cultured corms. Higher ethylene and jasmonic acid contents were also detected in all arrowhead samples, demonstrating that these hormones may play potential roles in the rhizosphere pressure response and corm expansion. The expression of genes participating in hormone signaling could explain the rising accumulation of certain hormones. Our current results draw an extensive model to reveal the potential regulation mechanism of arrowhead corm expansion promoted by rhizosphere pressure, which will provide important references for further studying the molecular mechanism of rhizosphere pressure modulating the development of underground storage organs in other plants.

Variation in the essential oil composition and in silico analysis of anti-inflammatory potential of Balkan endemic species Achillea clypeolata Sm

This research investigated a Balkan endemic species, Achillea clypeolata, collected from two locations (Dobrostan and Ivaylovgrad) in Bulgaria and two locations (Ozren and Rtanj) in Serbia. The goal was to compare the essential oil (EO) of A. clypeolata from these four localities. The EO was isolated from dry aboveground plant parts by hydrodistillation, and the identification of the EO constituents was carried out by GC-MS analyses. Principal Component Analysis (PCA), correlation analysis, and an unrooted cluster tree were used to define distinctions in the presence of volatile compounds in A. clypeolata EO. Results showed that A. clypeolata of Serbian origin (Ozren and Rtanj) contained 1,8-cineole as the main constituent, and belonged to the previously described 1,8-cineole as a dominant compound in the EO profile. On the other hand, the results from Bulgaria show an evident chemical diversification within the A. clypeolata species, as 1,8-cineole (23.2%), camphor (5.0%) and borneol (8.9%) prevailed in the EO of the studied samples collected from Ivaylovgrad, while borneol (22.6%), β-eudesmol (12.7%) and elemol (7.8%) were the main ones in the EO from Dobrostan. In sillico analysis revealed the high anti-inflammatory potential of A. clypeolata, which may be highly diverse depending on the population and active compounds it contains.

Plutonium Accumulation by Vegetation on Different Soils

The high variability of the plutonium transfer factors presented in the literature makes it relevant to study the mechanisms that affect its migration ability and its availability for vegetation. The variability of transfer factors is explained by different properties of soils, since the redox potential and soil acidity can significantly affect the mobility of plutonium. In the vegetation experiment, the migration of plutonium in the “soil-agricultural plant” system was studied for different types of soils. The content of 239 + 240Pu was analyzed by alpha spectrometry with preliminary radiochemical isolation. Plutonium migration parameters were determined using barley (Hordeum) and beans (Fabaceae) as test cultures. The plutonium accumulation coefficients obtained in the course of vegetation experiments are in the range of 3.1 × 10–4–6.8 × 10–3, with an average value of 3.8 × 10–3 for the aboveground part of barley and 9.2 × 10–3–7.6 × 10–2, with an average value of 3.8 × 10–2 – for the root system of barley. The transfer factor range was 1.5 × 10–3–5.7 × 10–3 with an average value of 3.7 × 10–3 and 5.8 × 10–2–6.5 × 10–2 with an average value of 6.2 × 10–2 for the aboveground part and the root system of the beans, respectively. It has been determined that the nature of the plutonium distribution over the vegetative organs of the crops under consideration is non-uniform. On average, the plutonium transfer factor for the aboveground part of plants is lower than for the root part by more than 40 times. It has been determined that the accumulation of plutonium in the aboveground parts of plants growing on different types of soil is not the same for individual species/organs of agricultural plants. For the aboveground part of the agricultural crops under consideration, the transfer factors differ up to several orders of magnitude. In general, the accumulation of plutonium by vegetation growing on different soils types is arranged in the following row: soddy-podzolic (Retisol) and gray forest soil (Phaeozem) lowland peat-bog (Histosol) \( \gg \) typical chernozem (Chernozem). The smallest accumulation of plutonium by vegetation is observed in soils with a high content of organic matter. For the root system of plants, the dependence of the plutonium accumulation coefficients on the soil type is uncertain.

Phenolic compounds in Geranium dalmaticum (Beck) Rech. f. and G. macrorrhizum L. (Geraniaceae) growing in Croatia

The quantitative analysis of bioactive phenolic compounds was carried out for the first time in above-ground plant parts of Geranium dalmaticum (Beck) Rech. f. and G. macrorrhizum L. (Geraniaceae) from Croatia by means of UV-Vis spectrophotometric methods and HPLC analysis. Both species had similar contents of polyphenolic substances expressed as mg of standard equivalent /g of dried herbal sample: total polyphenols (217.60 ± 1.08 and 215.53 ± 1.10 mg/g), tannins (155.83 ± 0.60 and 157.73 ± 0.61 mg/g), total flavonoids (5.10 ± 0.10 and 5.53 ± 0.10 mg/g), and total phenolic acids (13.27 ± 1.34 and 15.33 ± 0.45 mg/g), respectively for G. dalmaticum and G. macrorrhizum. Only the content of phenolic acids was somewhat higher in G. macrorrhizum but it was not statistically significant (p > 0.05). HPLC analysis showed that, among seven tested phenolic compounds, only quercetin was quantified in G. dalmaticum (0.23 % of dry weight), and rutin in G. macrorrhizum (1.12 % of dry weight). The obtained results represent a useful basis for further research of phytochemicals and biological activities of G. dalmaticum and G. macrorrhizum extracts.