Aluminium (Al) stress is a major limiting factor for worldwide crop production in acid soils. In Arabidopsis thaliana, the TAA1-dependent local auxin biosynthesis in the root-apex transition zone (TZ), the major perception site for Al toxicity, is crucial for the Al-induced root-growth inhibition, while the mechanism underlying Al-regulated auxin accumulation in the TZ is not fully understood. In the present study, the role of auxin transport in Al-induced local auxin accumulation in the TZ and root-growth inhibition was investigated. Our results showed that PIN-FORMED (PIN) proteins such as PIN1, PIN3, PIN4 and PIN7 and AUX1/LAX proteins such as AUX1, LAX1 and LAX2 were all ectopically up-regulated in the root-apex TZ in response to Al stress and coordinately regulated local auxin accumulation in the TZ and root-growth inhibition. The ectopic up-regulation of PIN1 in the TZ under Al stress was regulated by both ethylene and auxin, with auxin signalling acting downstream of ethylene. Al-induced PIN1 up-regulation and auxin accumulation in the root-apex TZ was also regulated by the calossin-like protein BIG. Together, our results provide insight into how Al stress induces local auxin accumulation in the TZ and root-growth inhibition through the local regulation of auxin transport.

• Klíčová slova
• PIN1, aluminium, auxin transport, root growth, root-apex transition zone,
• MeSH
• Arabidopsis účinky léků   genetika   růst a vývoj   fyziologie   MeSH
• biologický transport MeSH
• ethyleny metabolismus   MeSH
• fyziologický stres MeSH
• hliník toxicita   MeSH
• kořeny rostlin účinky léků   genetika   růst a vývoj   metabolismus   MeSH
• kyseliny indoloctové metabolismus   MeSH
• membránové transportní proteiny genetika   metabolismus   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• proteiny vázající kalmodulin genetika   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin metabolismus   MeSH
• upregulace MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BIG protein, Arabidopsis MeSH Prohlížeč
• ethylene MeSH Prohlížeč
• ethyleny MeSH
• hliník MeSH
• kyseliny indoloctové MeSH
• membránové transportní proteiny MeSH
• PIN1 protein, Arabidopsis MeSH Prohlížeč
• proteiny huseníčku MeSH
• proteiny vázající kalmodulin MeSH
• regulátory růstu rostlin MeSH

Although the significance of apoplasmic barriers in roots with regards to the uptake of toxic elements is generally known, the contribution of apoplasmic bypasses (ABs) to cadmium (Cd) hyperaccumulation is little understood. Here, we employed a combination of stable isotopic tracer techniques, an ABs tracer, hydraulic measurements, suberin lamellae staining, metabolic inhibitors, and antitranspirants to investigate and quantify the impact of the ABs on translocation of Cd to the xylem in roots of a hyperaccumulating (H) ecotype and a non-hyperaccumulating (NH) ecotype of Sedum alfredii. In the H ecotype, the Cd content in the xylem sap was proportional to hydrostatic pressure, which was attributed to pressure-driven flow via the ABs. The contribution of the ABs to Cd transportation to the xylem was dependent on the Cd concentration applied to the H ecotype (up to 37% at the highest concentration used). Cd-treated H ecotype roots showed significantly higher hydraulic conductance compared with the NH ecotype (76 vs 52 × 10–8 m s–1MPa–1), which is in accordance with less extensive suberization due to reduced expression of suberin-related genes. The main entry sites of apoplasmically transported Cd were localized in the root apexes and lateral roots of the H ecotype, where suberin lamellae were not well developed. These findings highlight the significance of the apoplasmic bypass in Cd hyperaccumulation in hyperaccumulating ecotypes of S. alfredii.

• Klíčová slova
• Apoplasmic bypass, cadmium, hydraulic conductance, lateral roots, root apex, Sedum alfredii, suberin lamellae, trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS),
• MeSH
• ekotyp MeSH
• exprese genu MeSH
• kadmium metabolismus   MeSH
• kořeny rostlin metabolismus   MeSH
• lipidy genetika   fyziologie   MeSH
• Sedum genetika   metabolismus   MeSH
• xylém metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kadmium MeSH
• lipidy MeSH
• suberin MeSH Prohlížeč

Cytokinins (CKs) play a crucial role in many physiological and developmental processes at the levels of individual plant components (cells, tissues, and organs) and by coordinating activities across these parts. High-resolution measurements of intracellular CKs in different plant tissues can therefore provide insights into their metabolism and mode of action. Here, we applied fluorescence-activated cell sorting of green fluorescent protein (GFP)-marked cell types, combined with solid-phase microextraction and an ultra-high-sensitivity mass spectrometry (MS) method for analysis of CK biosynthesis and homeostasis at cellular resolution. This method was validated by series of control experiments, establishing that protoplast isolation and cell sorting procedures did not greatly alter endogenous CK levels. The MS-based method facilitated the quantification of all the well known CK isoprenoid metabolites in four different transgenic Arabidopsis thaliana lines expressing GFP in specific cell populations within the primary root apex. Our results revealed the presence of a CK gradient within the Arabidopsis root tip, with a concentration maximum in the lateral root cap, columella, columella initials, and quiescent center cells. This distribution, when compared with previously published auxin gradients, implies that the well known antagonistic interactions between the two hormone groups are cell type specific.

• MeSH
• Arabidopsis cytologie   metabolismus   MeSH
• biologický transport MeSH
• cytokininy metabolismus   MeSH
• extrakce na pevné fázi MeSH
• kořeny rostlin cytologie   metabolismus   MeSH
• kyseliny indoloctové metabolismus   MeSH
• meristém metabolismus   MeSH
• metabolom MeSH
• miniaturizace MeSH
• orgánová specificita MeSH
• protoplasty metabolismus   MeSH
• průtoková cytometrie MeSH
• separace buněk MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytokininy MeSH
• kyseliny indoloctové MeSH
• zelené fluorescenční proteiny MeSH

The onset of rapid cell elongation occurred at different distances from the apex in various tissues of the primary root of maize (Zea mays L.). Furthermore, the comparison of these distances with those determined for the cessation of mitotic divisions revealed a considerable discrepancy. The onset of rapid cell elongation was realized much farther from the root apex than the cessation of cell divisions and therefore a distinct region could be distinguished in every examined maize root tissue. This region was denoted the region of postmitotic 'isodiametric' cell growth. Cells in this region grew in width as well as in length and obtained approximately a square-isodiametric shape. They were also characterized, as are cells in the meristem, by intense nucleic-acid metabolism. This prominent postmitotic 'isodiametric' cell growth was observed in both polyploid and diploid tissues, and indicates that postmitotic 'isodiametric' cell growth, like mitotic division and cell elongation growth, represents an important developmental stage in plant cell ontogeny.

• Publikační typ
• časopisecké články MeSH

Cytokinins (CKs) are pivotal plant hormones that have crucial roles in plant growth and development. However, their isolation and quantification are usually challenging because of their extremely low levels in plant tissues (pmol g-1 fresh weight). We have developed a simple microscale magnetic immunoaffinity-based method for selective one-step isolation of CKs from very small amounts of plant tissue (less than 0.1 mg fresh weight). The capacity of the immunosorbent and the effect of the complex plant matrix on the yield of the rapid one-step purification were tested using a wide range of CK concentrations. The total recovery range of the new microscale isolation procedure was found to be 30-80% depending on individual CKs. Immunoaffinity extraction using group-specific monoclonal CK antibodies immobilized onto magnetic microparticles was combined with a highly sensitive ultrafast mass spectrometry-based method with a detection limit close to one attomole. This combined approach allowed metabolic profiling of a wide range of naturally occurring CKs (bases, ribosides and N9 -glucosides) in 1.0-mm sections of the Arabidopsis thaliana root meristematic zone. The magnetic immunoaffinity separation method was shown to be a simple and extremely fast procedure requiring minimal amounts of plant tissue.

• Klíčová slova
• Arabidopsis thaliana, cytokinins, immunoaffinity separation, magnetic microparticles, metabolite profiling, technical advance,
• MeSH
• Arabidopsis chemie   MeSH
• cytokininy chemie   izolace a purifikace   MeSH
• kořeny rostlin chemie   MeSH
• magnetické nanočástice * MeSH
• regulátory růstu rostlin chemie   izolace a purifikace   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytokininy MeSH
• magnetické nanočástice * MeSH
• regulátory růstu rostlin MeSH

This article deals with the unusual course of failed revascularization/revitalization cases. Up to this date the evidence of success and failure rates of revascularization/revitalization treatment is scarce. These case reports present "unsuccessful" revascularization/revitalization treatment of permanent immature teeth with apical periodontitis. Although the teeth were treated by protocol suggested by the American Association of Endodontists and the symptoms disappeared, maturation of teeth continued, and periapical lesion was reduced, the teeth went symptomatic during the follow-up. Subsequently, regular root canal treatment was performed. Despite chronic infection that was probably left inside the root canal after a disinfection protocol, the secondary aims of the treatment were achieved even when the primary ones were not. The possible causes of failures of revascularization/revitalization treatment and their prevention are discussed.

• Klíčová slova
• Apical periodontitis, immature tooth, revascularization, revitalization, root maturation,
• MeSH
• apexifikace metody   MeSH
• dítě MeSH
• fyziologická neovaskularizace MeSH
• hrot zubního kořene růst a vývoj   patologie   MeSH
• lidé MeSH
• nekróza zubní dřeně terapie   MeSH
• periapikální periodontitida terapie   MeSH
• preparace kořenového kanálku metody   MeSH
• prostředky na výplach kořenových kanálků terapeutické užití   MeSH
• řezáky MeSH
• terapie kořenového kanálku metody   MeSH
• terapie neúspěšná * MeSH
• výplňové materiály kořenových kanálků terapeutické užití   MeSH
• zubní kořen účinky léků   růst a vývoj   patologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• prostředky na výplach kořenových kanálků MeSH
• výplňové materiály kořenových kanálků MeSH

Immunogold electron microscopy (EM) study of Arabidopsis root apices analyzed using specific IAA antibody and high-pressure freeze fixation technique allowed, for the first time, vizualization of subcellular localization of IAA in cells assembled intactly within plant tissues. Our quantitative analysis reveals that there is considerable portion of IAA gold particles that clusters within vesicles and membraneous compartments in all root apex cells. There are clear tissue-specific and developmental differences of clustered IAA in root apices. These findings have significant consequences for our understanding of this small molecule which is controlling plant growth, development and behavior.

• Klíčová slova
• Arabidopsis, Brefeldin A, IAA, auxin, endocytosis, polar auxin transport, roots, secretion, vesicles,
• Publikační typ
• časopisecké články MeSH

The development of the root apex is determined by progress of cells from the meristematic region to the successive post-mitotic developmental zones for transition, cell elongation and final cell differentiation. We addressed root development, tissue architecture and root developmental zonation by means of light-sheet microscopic imaging of Arabidopsis thaliana seedlings expressing END BINDING protein 1c (EB1c) fused to green fluorescent protein (GFP) under control of native EB1c promoter. Unlike the other two members of the EB1 family, plant-specific EB1c shows prominent nuclear localization in non-dividing cells in all developmental zones of the root apex. The nuclear localization of EB1c was previously mentioned solely in meristematic cells, but not further addressed. With the help of advanced light-sheet microscopy, we report quantitative evaluations of developmentally-regulated nuclear levels of the EB1c protein tagged with GFP relatively to the nuclear size in diverse root tissues (epidermis, cortex, and endodermis) and root developmental zones (meristem, transition, and elongation zones). Our results demonstrate a high potential of light-sheet microscopy for 4D live imaging of fluorescently-labeled nuclei in complex samples such as developing roots, showing capacity to quantify parameters at deeper cell layers (e.g., endodermis) with minimal aberrations. The data presented herein further signify the unique role of developmental cell reprogramming in the transition from cell proliferation to cell differentiation in developing root apex.

• Klíčová slova
• development, end-binding 1c (EB1c), light-sheet microscopy, nucleus, root apex, transition zone,
• Publikační typ
• časopisecké články MeSH

Uptake of (14)C-labeled fluoranthene ([(14)C]FLT) via both roots and leaves of Pisum sativum seedlings and distribution of [(14) C] in plants by both acropetal and basipetal transport was evaluated. The highest [(14)C] level was found in the root base (≈270 × 10(4) dpm/g dry wt) and the lowest level in the stem apex (<2 × 10(4) dpm/g dry wt) after just 2 h of root exposure. For foliar uptake, the highest level of [(14)C] was found in the stem and root apex (both ≈2 × 10(4) dpm/g dry wt) (except for treated leaves), while the lowest level was found in the root base (<0.6 × 10(4) dpm/g dry wt).

• Klíčová slova
• Fate and transport, Pea plant, Phytotoxicity, Polycyclic aromatic hydrocarbons, Root and foliar uptake,
• MeSH
• biologický transport MeSH
• fluoreny analýza   metabolismus   MeSH
• hrách setý metabolismus   MeSH
• kořeny rostlin metabolismus   MeSH
• látky znečišťující životní prostředí analýza   metabolismus   MeSH
• listy rostlin metabolismus   MeSH
• monitorování životního prostředí MeSH
• radioizotopy uhlíku analýza   metabolismus   MeSH
• stonky rostlin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fluoranthene MeSH Prohlížeč
• fluoreny MeSH
• látky znečišťující životní prostředí MeSH
• radioizotopy uhlíku MeSH

Pharmaceuticals belong to pseudo-persistent pollutants because of constant entry into the environment and hazardous potential for non-target organisms, including plants, in which they can influence biochemical and physiological processes. Detailed analysis of results obtained by microscopic observations using fluorescent dyes (berberine hemisulphate, Fluorol Yellow 088), detection of phytohormone levels (radioimmunoassay, enzyme-linked immune sorbent assay) and thermogravimetric analysis of lignin content proved that the drug naproxen (NPX) can stimulate the formation of root structural barriers. In the primary root of plants treated with 0.5, 1, and 10 mg/L NPX, earlier Casparian strip formation and development of the whole endodermis circle closer to its apex were found after five days of cultivation (by 9-20% as compared to control) and after ten days from 0.1 mg/L NPX (by 8-63%). Suberin lamellae (SL) were deposited in endodermal cells significantly closer to the apex under 10 mg/L NPX by up to 75%. Structural barrier formation under NPX treatment can be influenced indirectly by auxin-supported cell division and differentiation caused by its eight-times higher level under 10 mg/L NPX and directly by stimulated SL deposition induced by abscisic acid (higher from 0.5 mg/L NPX), as proved by the higher proportion of cells with SL in the primary root base (by 8-44%). The earlier modification of endodermis in plant roots can help to limit the drug transfer and maintain the homeostasis of the plant.

• Klíčová slova
• Casparian strips, NSAID, Phytohormones, Root growth dynamics, Suberin lamellae,
• MeSH
• hrách setý MeSH
• kořeny rostlin chemie   MeSH
• kyselina abscisová * MeSH
• kyseliny indoloctové analýza   MeSH
• naproxen * toxicita   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyselina abscisová * MeSH
• kyseliny indoloctové MeSH
• naproxen * MeSH