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1.
Viera Banásová Othmar Horak Milada Čiamporová Miriam Nadubinská Irene Lichtscheidl 《Biologia》2006,61(4):433-439
We investigated the composition of the vegetation in two former mining regions in Central Slovakia: Banská Štiavnica with
predominant Pb-Zn contamination and Staré Hory with a very high Cu content in the soil. Old heaps rich in heavy metals are
covered with specific vegetation. On the Cu-rich spoil heaps, species-poor plant communities with prevailing Agrostis stolonifera, Avenella flexuosa, Acetosella vulgaris, Arabidopsis arenosa, Silene dioica, and S. vulgaris occur. Species such as Agrostis capillaris, Acetosella vulgaris, Arabidopsis arenosa, and Thlaspi caerulescens appear frequently on Pb-Zn mine wastes. Several differences in the vegetation structure were detected between the Pb-Zn and
Cu mine heaps; higher amounts of vascular plants and fewer lichen species covered the Pb-Zn mine heaps. For the Cu mine heaps,
on the contrary a small number of vascular species but a high number and coverage of lichen species, especially Ceratodon purpureus and Cladonia arbuscula subsp. mitis were typical. The non-metalliferous meadows in the vicinity of the mines showed uniform structure but a higher species diversity. 相似文献
2.
MARIÁN PERNÝ VLADISLAV KOLARIK L'UBO MAJESKÝ PAVOL MÁRTONFI 《Botanical journal of the Linnean Society. Linnean Society of London》2008,157(3):475-485
Cytogeographical variability within the Phleum pratense group in the Carpathians and adjacent part of Pannonian lowland, based on 132 populations analysed by flow cytometry, is described. Only diploid and hexaploid plants were detected among 635 samples from the studied area. Diploids were found to be less frequent (127 plants, 20%) than hexaploids (508, 80%). With the exception of the single pure diploid population, diploids always co-occured with hexaploids (30 localities, 22.7%). The majority of populations (101, 76.5%) consisted of hexaploid plants. Most mixed populations occur in the Western Carpathians (26). In the Eastern Carpathians, mixed populations are much rarer, with three populations in Ukraine and one in Romania. In the Southern Carpathians, only hexaploids occur. The conventional taxonomic concept of the two species, diploid P. bertolonii and hexaploid P. pratense , was followed in spite of their sympatric occurence. Distribution maps based on chromosome number data from previous studies and on ploidy level estimates are given for both species in the studied area. The pattern of different distribution of the two taxa within the Carpathians is discussed. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 475–485. 相似文献
3.
Marek Vaculík Alexander Lux Miroslava Luxová Eiichi Tanimoto Irene Lichtscheidl 《Environmental and Experimental Botany》2009,67(1):52-58
The influence of silicon on the growth of maize plants cultivated in hydroponics in the presence of cadmium (5 μM) was investigated. Four different treatments were used: Control (C), Cadmium (Cd), Silicon (Si) and Cadmium plus Silicon (Cd + Si). The Si concentration was 35 mM. Thirteen-day-old plants were harvested. Growth parameters (length of primary seminal root, leaf area of first and second fully developed leaves, fresh and dry weight of below- and above-ground parts of the plants), and Cd concentration and total amount of Cd in the below- and above-ground parts were determined. In roots, the development of the endodermal barrier was observed by fluorescent staining with Fluorol yellow 088.Inhibitory effects of Cd on plant growth were observed. Silicon treatment in the absence of Cd had positive effects on most of observed growth parameters compared with the control. Moreover, Si in the Cd + Si treatment improved all growth parameters compared with the cadmium treatment. Silicon increased the cell-wall extensibility both in Si and Cd + Si treatments when compared with the control. Alleviation of the Cd-inhibitory effect on maize plants by Si was not due to exclusion of Cd from the plant; in contrast, Cd concentration in below- and above-ground plant parts and the total amount of Cd per plant were significantly higher in the Cd + Si plants than in the Cd treatment. The increased Cd content in Cd + Si plants was correlated with the development of the endodermis; during the second stage of endodermal development, suberin lamellae were formed at a greater distance from the root apex in the Cd + Si than in the Cd treatment. Silicon itself did not influence the development of suberin lamellae in the maize roots compared with the control. 相似文献
4.
We analysed cell wall formation in rapidly growing root hairs of Triticum aestivum under reduced turgor pressure by application of iso- and hypertonic mannitol solutions. Our experimental series revealed an osmotic value of wheat root hairs of 150 mOsm. In higher concentrations (200–650 mOsm), exocytosis of wall material and its deposition, as well as callose synthesis, still occurred, but the elongation of root hairs was stopped. Even after strong plasmolysis when the protoplast retreated from the cell wall, deposits of wall components were observed. Labelling with DiOC6(3) and FM1-43 revealed numerous Hechtian strands that spanned the plasmolytic space. Interestingly, the Hechtian strands also led towards the very tip of the root hair suggesting strong anchoring sites that are readily incorporated into the new cell wall. Long-term treatments of over 24 h in mannitol solutions (150–450 mOsm) resulted in reduced growth and concentration-dependent shortening of root hairs. However, the formation of new root hairs does occur in all concentrations used. This reflects the extraordinary potential of wheat root cells to adapt to environmental stress situations. 相似文献
5.
Endocytosis and vesicle trafficking during tip growth of root hairs 总被引:13,自引:0,他引:13
Summary. The directional elongation of root hairs, “tip growth”, depends on the coordinated and highly regulated trafficking of vesicles
which fill the tip cytoplasm and are active in secretion of cell wall material. So far, little is known about the dynamics
of endocytosis in living root hairs. We analyzed the motile behaviour of vesicles in the apical region of living root hairs
of Arabidopsis thaliana and of Triticum aestivum by live cell microscopy. For direct observation of endocytosis and of the fate of endocytic vesicles, we used the fluorescent
endocytosis marker dyes FM 1-43 and FM 4-64. Rapid endocytosis was detected mainly in the tip, where it caused a bright fluorescence
of the apical cytoplasm. The internalized membranes proceeded through highly dynamic putative early endosomes in the clear
zone to larger endosomal compartments in the subapical region that are excluded from the clear zone. The internalized cargo
ended up in the dynamic vacuole by fusion of large endosomal compartments with the tonoplast. Before export to these lytic
compartments, putative early endosomes remained in the apical zone, where they most probably recycled to the plasma membrane
and back into the cytoplasm for more than 30 min. Endoplasmic reticulum was not involved in trafficking pathways of endosomes.
Actin cytoskeleton was needed for the endocytosis itself, as well as for further membrane trafficking. The actin-depolymerizing
drug latrunculin B modified the dynamic properties of vesicles and endosomes; they became immobilized and aggregated in the
tip. Treatment with brefeldin A inhibited membrane trafficking and caused the disappearance of FM-containing vesicles and
putative early endosomes from the clear zone; labelled structures accumulated in motile brefeldin A-induced compartments.
These large endocytic compartments redispersed upon removal of the drug. Our results hence prove that endocytosis occurs in
growing root hairs. We show the localization of endocytosis in the tip and indicate specific endomembrane compartments and
their recycling.
Correspondence and reprints: Institute of Botany, Slovak Academy of Sciences, Dubravska cesta 14, 845 23 Bratislava, Slovak
Republic. 相似文献
6.
Derksen J Janssen GJ Wolters-Arts M Lichtscheidl I Adlassnig W Ovecka M Doris F Steer M 《The Plant journal : for cell and molecular biology》2011,68(3):495-506
A major question in pollen tube growth in planta remains: do the pollen tube walls form a barrier to interaction with the environment? Using cryo‐FESEM, we directly assessed the 3D construction and porosity of tobacco pollen tube walls. Fractured mature primary walls showed a 40–50 nm spaced lattice of continuous fibers interconnected by short rods in the primary wall. These observations agree with TEM observations of sectioned walls. In the secondary callose wall, for which no structure is visible using TEM, cryo‐FESEM also revealed a 50 nm lattice consisting of longer fibers, approximately 10–15 nm wide, with rod‐like, thinner interconnections at angles of approximately 90° with the longer fibers. Such architecture may reflect functional needs with respect to porosity and mechanical strength. The wall does not form a mechanical barrier to interaction with the environment and is gained at low cost. Cryo‐FESEM additionally revealed another special feature of the wall: the tubes were tiled with scales or rings that were highly conspicuous after pectin extraction with EDTA. These rings cause the typical banding patterns of pectin that are commonly seen in pollen tubes during oscillatory growth, as confirmed by staining with toluidine blue as well as by DIC microscopy. Growth analysis by VEC‐LM showed that the ring‐ or scale‐like structures of the primary wall consist of material deposited prior to the growth pulses. The alternating band pattern seen in the callose wall is probably imposed by constrictions resulting from the rings of the primary wall. 相似文献
7.
Sinem DEMRBA-SARIKAYA Hatice AKIR Devrim G
ZÜAIK Yunus AKKO 《Turkish Journal of Biology》2021,45(3):235
Autophagy and DNA repair are two essential biological mechanisms that maintain cellular homeostasis. Impairment of these mechanisms was associated with several pathologies such as premature aging, neurodegenerative diseases, and cancer. Intrinsic or extrinsic stress stimuli (e.g., reactive oxygen species or ionizing radiation) cause DNA damage. As a biological stress response, autophagy is activated following insults that threaten DNA integrity. Hence, in collaboration with DNA damage repair and response mechanisms, autophagy contributes to the maintenance of genomic stability and integrity. Yet, connections and interactions between these two systems are not fully understood. In this review article, current status of the associations and crosstalk between autophagy and DNA repair systems is documented and discussed. 相似文献
8.
Aylin
ZDEMR BAHADIR Bertan Koray BALCIOLU Müge SERHATLI eyma IIK Berrin ERDA 《Turkish Journal of Biology》2021,45(6):674
Gelatinases A and B, which are members of the matrix metalloproteinase (MMP) family, play essential roles in cancer development and metastasis, as they can break down basal membranes. Therefore, the determination and inhibition of gelatinases is essential for cancer treatment. Peptides that can specifically block each gelatinase may, therefore, be useful for cancer treatment. In this study, subtractive panning was carried out using a 12-mer peptide library to identify peptides that block gelatinase A activity (MMP-2), which is a key pharmacological target. Using this method, 17 unique peptide sequences were determined. MMP-2 inhibition by these peptides was evaluated through zymogram analyses, which revealed that four peptides inhibited MMP-2 activity by at least 65%. These four peptides were synthesized and used for in vitro wound healing using human umbilical vein endothelial cells, and two peptides, AOMP12 and AOMP29, were found to inhibit wound healing by 40%. These peptides are, thus, potential candidates for MMP-2 inhibition for cancer treatment. Furthermore, our findings suggest that our substractive biopanning screening method is a suitable strategy for identifying peptides that selectively inhibit MMP-2. 相似文献
9.
Summary The cortical endoplasmic reticulum (ER) of living onion inner epidermal cells has been studied by video-microscopy. We observed local movements of individual ER membranes, which cause transformations of the polygonal net. Membrane tubules glide along one another, causing transfiguration, reduction and decomposition of polygons. Membrane tubules and lamellae also extend from the existing net and thus increase the amount of ER. These movements occur in close correlation with organelle movements, suggesting a structural coalignment of the net with actin microfilaments (MFs). The membranes in the cortical cytoplasm are not distributed randomly but are tethered to certain domains; even when dislocated, they return to such anchoring points. This was not observed with ER reaching deeper into the cytoplasm. We therefore propose that close associations of ER and the plasma membrane (PM) stabilize the cortical ER and may stabilize coaligning MFs as well.Abbreviations AVEC-DIC
Allen video-enhanced contrast-differential interference contrast
- DiOC6 (3)
3,3-dihexyloxacarbocyanine iodide
- ER
endoplasmic reticulum
- MF
microfilament
- MT
microtubules
- PM
plasma membrane
Dedicated to the memory of Professor Oswald Kiermayer 相似文献
10.
Genya Mitani Masato Sato Jeong IK Lee Nagatoshi Kaneshiro Miya Ishihara Naoshi Ota Mami Kokubo Hideaki Sakai Tetsutaro Kikuchi Joji Mochida 《BMC biotechnology》2009,9(1):17-11