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As chemical messengers, phytohormones can enhance the tolerance of plants to stress caused by toxic elements (TEs) such as cadmium (Cd), lead (Pb), and zinc (Zn). This study investigated the combined toxicity of Cd, Pb, and Zn, and its impact on stress phytohormones (jasmonates, salicylic acid, and abscisic acid), in oat (Avena sativa L.) using anthropogenically contaminated soil in a 4-week pot experiment. The uptake of TEs by the roots increased in the multi-contaminated soil, while Zn was the only TE to be translocated to the leaves. The toxic effect of the TEs was assessed in terms of plant growth, revealing a decline in leaf dry biomass, whereas the impact on the roots was insignificant. These findings align with the levels of stress phytohormones. An increase in bioactive forms of stress phytohormones in leaves due to TEs indicates TE toxicity and leaf sensitivity. Conversely, low levels of these phytohormones, along with crosstalk between them, suggest reduced defense against TEs in the roots. The abundance of stress phytohormones declined in the following order: salicylic acid > jasmonates > abscisic acid. These results help to understand the mechanism by which plants respond to TEs, particularly their combined toxicity.

This work presents the results of an investigation of an assemblage of secondary Sc-minerals from the intraplutonic metaluminous pegmatite Kozichovice II, Trebic Pluton, Czech Republic. The assemblage was formed by hydrothermally-induced dissolution of primary Sc-enriched (≈1.6 wt.% Sc2O3) columbite-(Mn) followed by in situ reprecipitation of volumetrically dominant fersmite (≈0.16 wt.% Sc2O3) and minor nioboheftetjernite (ScNbO4). Subsequent hydrothermal processes resulted in the formation of fluorcalciomicrolite + Sc-minerals (thortveitite + kristiansenite) + titanite. The mass balance calculations (based on EPMA-derived mineral compositions, mineral proportions obtained from TIMA automated mineralogy and textural observations) revealed that the amount of Sc released from the replaced mass of columbite-(Mn) is significantly higher than the amount of Sc incorporated in the mass of the secondary minerals. This indicates that part of the Sc was mobilised and released to the host rocks (pegmatite and granite). The secondary mineral assemblages indicate elevated Ca activity in the alteration fluids. Other occurrences of Sc-minerals in pegmatites (Baveno Pluton and Heftetjern pegmatite) show remarkable similarities in the paragenetic position of Sc-minerals (late hydrothermal/replacement minerals), including the high activity of Ca in fluids during their formation. The high activity of Ca in fluids during the metasomatic replacement of Sc-enriched precursors causes the formation of the volumetrically dominant Sc incompatible phases, followed by a local supersaturation of Sc resulting in the crystallisation of secondary Sc-minerals.

A pot experiment was undertaken to investigate the effect of Cd, Pb and Zn multi-contamination on the physiological and metabolic response of carrot (Daucus carota L.) after 98 days of growth under greenhouse conditions. Multi-contamination had a higher negative influence on leaves (the highest Cd and Zn accumulation) compared to the roots, which showed no visible change in terms of anatomy and morphology. The results showed the following: (i) significantly higher accumulation of Cd, Zn, and Pb in the multi-contaminated variant (Multi) compared to the control; (ii) significant metabolic responses—an increase in the malondialdehyde content of the Multi variant compared to the control in the roots (by 20%), as well as in the leaves (by 53%); carotenoid content in roots decreased by 31% in the Multi variant compared with the control; and changes in free amino acids, especially those related to plant stress responses. The determination of hydroxyproline and sarcosine may reflect the higher sensitivity of carrot leaves to multi-contamination in comparison to roots. A similar trend was observed for the content of free methionine (significant increase of 31% only in leaves); (iii) physiological responses (significant decreases in biomass, changes in gas-exchange parameters and chlorophyll a); and (iv) significant changes in enzymatic activities (chitinase, alanine aminopeptidase, acid phosphatase) in the root zone.

The impact of toxic elements (TEs) contaminating the root zone of Lupinus angustifolius L. on enzymatic activities, nitrification rate, and changes in the root system was evaluated. Lupine was cultivated in a pot experiment using two types of soil – control and contamination (with a high degree of arsenic (As), cadmium (Cd), lead (Pb), and zinc (Zn) contamination). After harvesting lupine biomass, enzyme activities (β-glucosidase, acid phosphatase, arylsulphatase, lipase, chitinase, cellobiohydrolase, alanine aminopeptidase, and leucine aminopeptidase) in soils were analysed. Enzyme activities decreased with TE soil contamination. According to our results, arylsulphatase was found to be the most sensitive soil enzyme to TEs. The nitrification rate is closely related to soil contamination and plant activity, as it stimulates microbial growth and multiplication through root exudates. The close correlations confirmed this relationship (r = 0.73−0.99). An increasing trend in TE contents in the roots was observed with soil contamination. Plant hormones are crucial in regulating root growth and development under stress conditions. The levels of determined phytohormones in our experiment (auxins, abscisic acid (ABA), salicylic acid (SA), and bioactive cytokinins (bCKs)) were lower in the contamination compared to the control. Correlations confirmed a significant negative relationship between the TE content in the roots and the contents of phytohormones (auxins: r = –0.96 to –0.97; ABA: r = –0.83 to –0.86; SA: r = –0.95 to –0.99, bCKs: r = –0.87 to –0.93). The ratios of these hormones (not their absolute values) appear to be the determining factor for regulating root development and protecting plants from oxidative stress.

This work presents data for the mineral assemblages, composition and Raman spectroscopy of proximal secondary Be and associated minerals in pseudomorphs after beryl from granitic pegmatites located along the contacts of major regional geological units. The pegmatites differ in their position relative to the ductile to brittle shear zones within the Rozna-Olsi. ore field (U-deposit), Czech Republic. Extensive dissolution of beryl crystals in the beryl-columbite pegmatites Drahonin IV and Vezna I situated within or close to the shear zones is evident in contrast to minor alteration of beryl in the Dolni Rozinka and Kovarova pegmatites located outside of the shear zones. Near-total replacement of beryl crystals, up to 40 cm in length, from the Drahonin IV pegmatite, located in the Olsi shear zone formed the following secondary Be minerals in order of their abundance: bavenite-bohseite > bertrandite >> milarite > hydroxylgugiaite. This assemblage is also characterised by the presence of sulfides (pyrite, galena, sphalerite) and zeolites. Such an extensive replacement process required a substantial fluid flow and is very possibly related to the pre-uranium quartz-sulfide and carbonate-sulfide mineralisation events Rozna Olsi ore field. Alteration products resulting from breakdown of beryl Vezna I pegmatite follow the sequential substages (bertrandite + ± K-feldspar ± harmotone → epididymite + K-feldspar → hydroxylgugiaite + K-feldspar) and locally show cross-cutting textures. These assemblages were generated by post-magmatic residual fluids (early assemblage bertrandite + K-feldspar) as well as fluids related to a retrograde stage of metamorphism, compositionally contrasting with the host serpentinite, and perhaps also hydrothermal processes associated with the Olsi shear zone. The pegmatites Dolni Rozinka, located outside of the shear zones, exhibit only a low degree of alteration and have differing textural and paragenetic development. Highly variable assemblages of secondary minerals after beryl are excellent mineral indicators of hydrothermal overprinting in granitic pegmatites during a variety of subsolidus processes.

The influence of toxic elements, such as arsenic (As), cadmium (Cd), lead (Pb), and zinc (Zn), in the root zone of As-hyperaccumulator Pteris cretica 'Albo-lineata' and non-As-hyperaccumulator P. straminea, on the enzymatic activity of β-glucosidase, dissolved organic carbon (C) in soil, toxic element accumulation in fern roots, and root biomass were evaluated in a pot experiment. Ferns were cultivated in soils from the locality of Suchdol (control) and Litavka (high contamination) for six months. For all toxic elements, an increasing trend in their contents in the roots was observed with soil contamination for both ferns. Differences between ferns were observed in As and Zn accumulation. Pteris cretica had a significantly higher As accumulation than P. straminea. Zinc accumulation in the roots showed an opposite trend. A significant difference between ferns was confirmed in the dissolved organic C content. Our results showed a significantly higher content of dissolved organic C in the P. straminea root zone than in P. cretica. The significant effect of toxic elements in the soil on β-glucosidase activity was observed. Toxic elements inhibited β-glucosidase activity in the root zone of P. cretica, and an increase in P. straminea was determined in the Litavka soil. The results suggest a higher sensitivity of P. straminea to toxic element contamination in soil, leading to increased β-glucosidase activity and increased dissolved organic C content.

This study investigated the metabolic adaptive responses to As contamination and As co-contamination with cadmium, lead, and zinc in the leaves and tubers of cherry radish (Raphanus sativus var. sativus Pers.). The response was assessed by measuring malondialdehyde levels, total phenolic content (TPC), total anthocyanin pigment (TAC), growth and stress phytohormone concentration, and free amino acid content. The characteristic As accumulation of single contamination resulted in a decrease in tuber growth. However, in the case of co-contamination, As uptake was influenced by the presence of other potentially toxic elements (PTEs), mainly zinc, with no significant effect on growth. Both contaminated treatments exhibited significant differences in metabolite levels among the organs, along with notable changes in their contents. Increases in malondialdehyde, TPC, and TAC indicated induced oxidative stress and an antioxidant response that was more pronounced by As co-contamination. Also, the results for phytohormones, which showed both increases and decreases, along with selected free amino acids (which showed increases), demonstrated a more significant influence of As co-contamination. Based on these findings, it can be concluded that the response of cherry radish to contaminated treatments exhibited significant differences in the studied parameters, along with variability in the results, reflecting the extent of the effects of PTEs that induce oxidative stress.

The paragenesis and composition of bavenite-bohseite were investigated in fifteen granitic pegmatites from the Bohemian Massif, Czech Republic. Three types distinct in their relation to primary Be precursors, mineral assemblages, morphology and origin were recognised: (1) primary hydrothermal bavenite-bohseite crystallised in miarolitic pockets from residual pegmatite fluids; and secondary bavenite-bohseite in two distinct types: (2) a proximal type restricted spatially to pseudomorphs after a primary Be mineral (beryl > phenakite, helvine-danalite); and (3) a distal type on brittle fractures and fissures of host pegmatite. The mineral assemblages are highly variable: (1) axinite-(Mn), smectite, calcite and pyrite; (2) bertrandite, milarite, secondary beryl, bazzite, K-feldspar, muscovite-illite, scolecite, gismondine-Ca, analcime, chlorite; and (3) muscovite, albite, quartz, epidote, pumpellyite-(Mg), pumpellyite-(Fe3+), titanite and chlorite. Electron microprobe analyses showed, in addition to major constituents (Si, Ca and Al), minor concentrations (in apfu) of Na (≤0.24), Fe (≤0.10), Mn (≤0.10) and F (≤0.36). The type 1 hydrothermal miarolitic bavenite-bohseite is mostly Al-rich (2.00-0.67 apfu) relative to type 2 proximal bavenite-bohseite and bohseite after beryl, phenakite and helvine-danalite (1.56-0.46, 0.70-0.05, 1.02-0.35 apfu, respectively); and type 3 distal bavenite-bohseite typically after beryl (1.63-0.09 apfu). Raman spectroscopy revealed that the distance between the OH- vibrational modes decreases with increasing bohseite component. The Al content of secondary type 2 proximal bavenite-bohseite is controlled by the composition of the Be precursor whereas type 3 distal bavenite-bohseite with beryl as the Be precursor is more variable and the composition is governed mainly by the composition of fluids. Calcium, a crucial component for bavenite-bohseite origins, was derived from residual pegmatite fluids (Vlastějovice, Vepice IV or Trebíc Plutons) or external sources (e.g. Drahonín IV, Věžná I or Marsíkov). Primary type 1 hydrothermal bavenite-bohseite from miarolitic pockets might have crystallised at T ≈ 300-400°C and P ≈ 200 MPa, whereas the secondary type 2 and 3 bavenite-bohseite formed at T ≈ 300-100°C and P ≈ 200-20 MPa.

Microlite-group minerals occur as common replacement products after primary and secondary columbite-group minerals (CGM) in albitised blocky K-feldspar and in coarse-grained, muscovite-rich units of the Schinderhübel I, Scheibengraben and Bienergraben beryl–columbite pegmatites in the Maršíkov District (Silesian Unit, Bohemian Massif, Czech Republic). Textural and compositional variations of microlite-group minerals were examined using electron probe micro-analyses and microRaman spectroscopy (μRS). A complex post-magmatic evolution of the pegmatites and the following microlite populations (Mic) and related processes were found: (1) precipitation of U, Na-rich and F-poor Mic I on cracks in CGM; (2) alteration of Mic I to U-rich together with Na- and F-poor Mic II; and (3) partial replacement of Mic I and II by Mic III with a distinct Na, U and Ti loss and Ca and F gain. Stage (2) includes an extensive leaching of Na, without U loss. The final stage (3) produced euhedral-to-subhedral oscillatory zoned Ca and F enriched Mic III with distinctly different composition to the previous F-poor and A- site vacant Mic II. Aggregates of fersmite are associated commonly with Mic III. Distal Mic IIId occurs locally on cracks in K-feldspar or quartz, with compositions analogous to Mic III. Compositional variations and textural features of microlite-group minerals during dissolution–reprecipitation processes serve as sensitive tracers of post-magmatic evolution in granitic pegmatites recording complex interactions between magmatic pegmatite units and externally derived, hydrothermal metamorphic fluids.