Ionic liquids are increasingly used for their superior properties. Four water-immiscible ionic liquids (butyltriethylammonium bis(trifluoromethylsulfonyl)imide, octyltriethylammonium bis(trifluoromethylsulfonyl)imide, dodecyltriethylammonium bis(trifluoromethylsulfonyl)imide, butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) and their water miscible precursors (bromides) were synthesized in a microwave reactor and by conventional heating. The best conditions for microwave-assisted synthesis concerning the yield and the purity of the product are proposed. The heating in the microwave reactor significantly shortened the reaction time. Biocide and ecotoxic effects of synthesized ionic liquids and their precursors were investigated. All tested compounds had at least a little effect on the growth or living of microorganisms (bacteria or mold). The precursor dodecyltriethylammonium bromide was found to be the strongest biocide, but posed a risk to the aquatic environment due to its relatively high EC50 value in the test with Vibrio fischeri. We assumed that apart from the alkyl chain length, the solubility in water, duration of action, or type of anion can influence the final biocide and ecotoxic effect.
- MeSH
- Aliivibrio fischeri účinky léků MeSH
- amoniové sloučeniny chemie MeSH
- antibakteriální látky chemická syntéza farmakologie MeSH
- antifungální látky chemická syntéza chemie farmakologie MeSH
- ekotoxikologie metody MeSH
- imidazoly chemie MeSH
- iontové kapaliny chemická syntéza farmakologie MeSH
- kvartérní amoniové sloučeniny chemická syntéza farmakologie MeSH
- mikrovlny MeSH
- preklinické hodnocení léčiv metody MeSH
- Publikační typ
- časopisecké články MeSH
Japanese knotweed (JK) is considered one of the most problematic invasive plants. Great attention was paid to research any possibilities of reducing its occurrence. This work deals with possibilities of easy transformation of JK into carbon adsorbent (AC), which is usable for sorption of diclofenac and paracetamol. Activated carbons were prepared by microwave heating using H3PO4, NaOH and sodium methanolate as the chemical agents. Characterization of AC's was carried out using BET, ATR-FTIR, SEM, adsorption equilibrium and kinetics experiments. The pseudo-second-order model showed the best similarity criteria for all studied systems adsorbent/adsorbate. The sorption efficiency was influenced by the choice of activating agent, where the π-π interactions between the planes of the obtained adsorbent and the aromatic rings of adsorbate and the interactions between the adsorbate and AC functional groups of the surface played an important role. AC-H3PO4 exhibited highest adsorption capacity for both diclofenac (87.09 mg.g-1) and paracetamol (136.61 mg.g-1).
The study aims to assess variability in leaf water isotopic enrichment occurring in the field under natural conditions. We focused on seasonal variation and difference between sun-exposed and shaded leaves. Isotopic composition (δ18O, δ2H) of leaf water was monitored in a beech tree (Fagus sylvatica L.) growing in the forest-meadow ecotone together with δ18O (2H) of water compartments which are in close relation to this signal, namely twig and soil water. The sampling was carried out in approximately two-week intervals during five consecutive vegetation seasons. The δ18O (2H) data showed a distinct seasonal pattern and a consistency in relative differences between the seasons and sample categories. Leaf water was the most isotopically enriched water compartment. The leaf water enrichment decreased toward the autumn reflecting the change in δ18O (2H) of source water and evaporative demands. The soil and twig water isotopic signal was depleted against current precipitation as it partly retained the isotopic signature from winter precipitation however the seasonal pattern of soil and twig water followed that of precipitation. No significant differences between sun-exposed and shaded samples were detected. Nevertheless, the observed strong seasonal pattern of isotope composition of leaf, twig and soil water should be taken into account when using leaf water enrichment for further calculations or modeling.
The initiation of stomata, microscopic valves in the epidermis of higher plants that control of gas exchange, requires a co-ordinated sequence of asymmetric and symmetric divisions, which is under tight environmental and developmental control. Arabidopsis leaves grown under elevated photosynthetic photon flux density have a higher density of stomata. STOMAGEN encodes an epidermal patterning factor produced in the mesophyll, and our observations indicated that elevated photosynthetic irradiation stimulates STOMAGEN expression. Our analysis of gain and loss of function of STOMAGEN further detailed its function as a positive regulator of stomatal formation on both sides of the leaf, not only in terms of stomatal density across the leaf surface but also in terms of their stomatal index. STOMAGEN function was rate limiting for the light response of the stomatal lineage in the adaxial epidermis. Mutants in pathways that regulate stomatal spacing in the epidermis and have elevated stomatal density, such as stomatal density and distribution (sdd1) and too many mouth alleles, displayed elevated STOMAGEN expression, suggesting that STOMAGEN is either under the direct control of these pathways or is indirectly affected by stomatal patterning, suggestive of a feedback mechanism. These observations support a model in which changes in levels of light irradiation are perceived in the mesophyll and control the production of stomata in the epidermis by mesophyll-produced STOMAGEN, and whereby, conversely, stomatal patterning, either directly or indirectly, influences STOMAGEN levels.
- MeSH
- Arabidopsis genetika růst a vývoj metabolismus účinky záření MeSH
- fotosyntéza MeSH
- listy rostlin růst a vývoj metabolismus účinky záření MeSH
- proteiny huseníčku genetika metabolismus MeSH
- průduchy rostlin genetika růst a vývoj metabolismus účinky záření MeSH
- regulace genové exprese u rostlin účinky záření MeSH
- signální transdukce MeSH
- světlo MeSH
- vývojová regulace genové exprese účinky záření MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND AND AIMS: Stomatal density (SD) generally decreases with rising atmospheric CO2 concentration, Ca. However, SD is also affected by light, air humidity and drought, all under systemic signalling from older leaves. This makes our understanding of how Ca controls SD incomplete. This study tested the hypotheses that SD is affected by the internal CO2 concentration of the leaf, Ci, rather than Ca, and that cotyledons, as the first plant assimilation organs, lack the systemic signal. METHODS: Sunflower (Helianthus annuus), beech (Fagus sylvatica), arabidopsis (Arabidopsis thaliana) and garden cress (Lepidium sativum) were grown under contrasting environmental conditions that affected Ci while Ca was kept constant. The SD, pavement cell density (PCD) and stomatal index (SI) responses to Ci in cotyledons and the first leaves of garden cress were compared. (13)C abundance (δ(13)C) in leaf dry matter was used to estimate the effective Ci during leaf development. The SD was estimated from leaf imprints. KEY RESULTS: SD correlated negatively with Ci in leaves of all four species and under three different treatments (irradiance, abscisic acid and osmotic stress). PCD in arabidopsis and garden cress responded similarly, so that SI was largely unaffected. However, SD and PCD of cotyledons were insensitive to Ci, indicating an essential role for systemic signalling. CONCLUSIONS: It is proposed that Ci or a Ci-linked factor plays an important role in modulating SD and PCD during epidermis development and leaf expansion. The absence of a Ci-SD relationship in the cotyledons of garden cress indicates the key role of lower-insertion CO2 assimilation organs in signal perception and its long-distance transport.
- MeSH
- Arabidopsis cytologie účinky léků MeSH
- buk (rod) cytologie účinky léků MeSH
- dehydratace MeSH
- Helianthus cytologie účinky léků MeSH
- kotyledon účinky léků fyziologie MeSH
- Lepidium cytologie účinky léků MeSH
- oxid uhličitý farmakologie MeSH
- počet buněk MeSH
- průduchy rostlin cytologie účinky léků MeSH
- životní prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We explored ability of reflectance vegetation indexes (VIs) related to chlorophyll fluorescence emission (R₆₈₆/R₆₃₀, R₇₄₀/R₈₀₀) and de-epoxidation state of xanthophyll cycle pigments (PRI, calculated as (R₅₃₁- R₅₇₀)/(R₅₃₁-R₅₇₀) to track changes in the CO₂ assimilation rate and Light Use Efficiency (LUE) in montane grassland and Norway spruce forest ecosystems, both at leaf and also canopy level. VIs were measured at two research plots using a ground-based high spatial/spectral resolution imaging spectroscopy technique. No significant relationship between VIs and leaf light-saturated CO₂ assimilation (A(MAX)) was detected in instantaneous measurements of grassland under steady-state irradiance conditions. Once the temporal dimension and daily irradiance variation were included into the experimental setup, statistically significant changes in VIs related to tested physiological parameters were revealed. ΔPRI and Δ(R₆₈₆/R₆₃₀) of grassland plant leaves under dark-to-full sunlight transition in the scale of minutes were significantly related to A(MAX) (R² = 0.51). In the daily course, the variation of VIs measured in one-hour intervals correlated well with the variation of Gross Primary Production (GPP), Net Ecosystem Exchange (NEE), and LUE estimated via the eddy-covariance flux tower. Statistical results were weaker in the case of the grassland ecosystem, with the strongest statistical relation of the index R₆₈₆/R₆₃₀ with NEE and GPP.
• Heterotrophic acquisition of substantial amounts of organic carbon by hemiparasitic plants was clearly demonstrated by numerous studies. Many hemiparasites are, however, also limited by competition for light preventing the establishment of their populations on highly productive sites. • In a growth-chamber experiment, we investigated the effects of competition for light, simulated by shading, on growth and heterotrophic carbon acquisition by the hemiparasite Rhinanthus alectorolophus attached to C(3) and C(4) hosts using analyses of biomass production and stable isotopes of carbon. • Shading had a detrimental effect on biomass production and vertical growth of the hemiparasites shaded from when they were seedlings, while shading imposed later caused only a moderate decrease of biomass production and had no effect on the height. Moreover, shading increased the proportion of host-derived carbon in hemiparasite biomass (up to 50% in shaded seedlings). • These results demonstrate that host-derived carbon can play a crucial role in carbon budget of hemiparasites, especially if they grow in a productive environment with intense competition for light. The heterotrophic carbon acquisition can allow hemiparasite establishment in communities of moderate productivity, helping well-attached hemiparasites to escape from the critical seedling stage.
- MeSH
- analýza rozptylu MeSH
- biomasa MeSH
- druhová specificita MeSH
- dusík metabolismus MeSH
- ekosystém MeSH
- fotosyntéza účinky záření MeSH
- heterotrofní procesy fyziologie účinky záření MeSH
- interakce hostitele a parazita fyziologie MeSH
- izotopové značení MeSH
- izotopy uhlíku MeSH
- kukuřice setá parazitologie účinky záření MeSH
- lineární modely MeSH
- Orobanchaceae růst a vývoj fyziologie účinky záření MeSH
- semenáček růst a vývoj účinky záření MeSH
- světlo MeSH
- uhlík metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
