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1.

001-es BibID:BIBFORM094879
Első szerző:Hörcsik Zsolt
Cím:Effects of chromium (VI) on growth, element and photosynthetic pigment composition of Chlorella pyrenoidosa / Zsolt Hörcsik, Viktor Oláh, Árpád Balogh, Ilona Mészáros, László Simon, Gyula Lakatos
Dátum:2006
ISSN:1588-385X
Megjegyzések:he effects of Cr(VI) were investigated on the growth rate, element, photosyn-thetic pigment and amino acid composition of Chlorella pyrenoidosa. Cr(VI) is toxic to Chlorella pyrenoidosa. The influence of chromium on cell density and cell number followed very similar trends, indicating that these growth responses might be correlated. The EC50 value for Cr(VI) were 2.0 mg dm-3, the lethal concentration of chromium appears to be approximately 20 mg dm-3for Chlorella pyrenoidosa. We have investigated the concentrations of chromium, calcium, mag-nesium and iron. The cells were fractionated into three fractions: cell wall fraction, membrane fraction, soluble fraction after the cells were disrupted. The amount of metals in whole cells and in each cell fraction was determined. Chromium uptake at each concentration was high within 3 days. Chlorella pyrenoidosa can accumulate chromium mainly (approximately 70%) in the cell wall. The concentrations of chromium and calcium show parallel changes with each other. A higher calcium concentration can be observed along with an increasing chromium concentration, both in the cell wall system and in the whole cells. Iron and magnesium concentration show a decreasing tendency. Cr(VI) caused a changes both in free amino acids and proline content. Both free amino acids and proline content increase with the increasing concentration of chro-mium. Chlorophyll a and b content show a decreasing , while OH-chlorophylls show increasing tendency. Rate of carotene ? and ? change grows with the increasing chromium concentration. The toxic properties of Cr(VI) can arise from the possibly free diffusion across cell membranes and strong oxidative potential. The toxicological impact of Cr(VI) originates from the action of this form itself as an oxidizing agent, as well as from the formation of free radicals during the reduction of Cr(VI) to Cr(III) occuring inside the cell.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény hazai lapban
folyóiratcikk
Chlorella pyrenoidosa
chromium
element composition
pigment pattern
Megjelenés:Acta Biologica Szegediensis. - 50 : 1-2 (2006), p. 19-23. -
További szerzők:Oláh Viktor (1980-) (biológus) Balogh Árpád Mészáros Ilona (1952-) (biológus) Simon László (1963-) (okleveles tartósítóipari mérnök) Lakatos Gyula (1949-) (ökológus)
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2.

001-es BibID:BIBFORM084987
Első szerző:Koncz Péter
Cím:Variability of leaf growth characteristics in the canopy of sessile oak and Austrian oak / Péter Koncz, Angéla Gáspár, Viktor Oláh, László Elek, Gyula Lakatos, Ilona Mészáros
Dátum:2005
ISSN:1588-385X
Megjegyzések:In this study the variability of leaf growth traits was investigated within the canopy ABSTRACT of the two dominant tree species of Quercetum petraeae-cerris forest community, covering 30 % of the present forested area in Hungary. The investigation were performed in the "Sikf©okut Project" LTER site (Jakucs 1985). We compared the present leaf growth traits of species with those reported by Virágh (1985) for years of 1973-1975 before the decline of sessile oak in the site. After bud break leaves of the two canopy layers exhibited different rate in the increase of leaf area (La) and leaf mass (Lm). In spring shade leaves showed more intense increase in leaf area than in leaf mass. This resulted in a transitional large reduction of SLM in the shade leaves. In case of sessile oak the full leaf size was achieved within the same period in 2003 and 2004 but the area of mature leaves were larger in both canopy layers in 2004 than in 2003. In case of sessile oak the area of mature leaves in growing seasons of 2003 and 2004 increased significantly as compared to the period before the forest decline (Virágh 1985). In the upper canopy layer of Austrian oak the leaf area and leaf mass did not differ significantly from those reported for the period before the forest decline. In the lower layer of the canopy, however, the increase of leaf area was observed but the leaf mass exhibited similar values. In 2004 the loss of leaf area in the sun layer was 17% and in the shade layer 6 % as a consequnce of photophagous damages. In case of Austrian oak the loss of leaf area was smaller and amounted only to 1-5%.
Tárgyszavak:Természettudományok Biológiai tudományok konferenciacikk
folyóiratcikk
sessile oak
Austrian oak
leaf growth
specific leaf mass
realtive leaf growth rate
Megjelenés:Acta Biologica Szegediensis. - 49 : 1-2 (2005), p. 149-150. -
További szerzők:Gáspár Angéla Oláh Viktor (1980-) (biológus) Elek László (biológus) Lakatos Gyula (1949-) (ökológus) Mészáros Ilona (1952-) (biológus)
Pályázati támogatás:T037961
OTKA
National Research and Development Proejct of Ministry of Education, Hungary (Forest and Climate Project
Egyéb
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3.

001-es BibID:BIBFORM085737
Első szerző:Mészáros Ilona (biológus)
Cím:Physiological plasticity of beech (Fagus sylvatica L.) under contrasting light conditions / I. Mészáros, Sz. Veres, R. Láposi, É. Sárvári, G. Lakatos, O. Mile, A. Gáspár
Dátum:2002
ISSN:1588-385X
Megjegyzések:In this work pigment composition and chlorophyll fluorescence characteristics were studied in seedlings of Fagus sylvatica regenerating in contrasting light environments of forest understory, forest edge and deforested area. The results have shown that the survival of beech seedlings under high light conditions in the forest edge and deforested area, as well as their acclimation to excess light require effective functional plasticity of the photosynthetic apparatus and protective mechanisms. Physiological acclimation of beech seedlings to high light involves significantly the carotenoids both in the short-term through the reversible conversion of violaxanthin to zeaxanthin and in the long-term through the increase of total carotenoid content and the size of xanthophyll cycle pool.
Tárgyszavak:Természettudományok Biológiai tudományok konferenciacikk
folyóiratcikk
beech
chlorophyll fluorescence
Fagus sylvatica
photoinhibition
photosynthesis
sun and shade adaptation
xanthophyll cycle
Megjelenés:Acta Biologica Szegediensis. - 46 : 3-4 (2002), p. 235-236. -
További szerzők:Veres Szilvia (1972-) (biológus, biológia középiskolai tanár, angol-magyar szakfordító) Láposi Réka (1976-) Sárvári Éva Lakatos Gyula (1949-) (ökológus) Mile Orsolya Gáspár Attila (1970-) (vegyész, kémikus)
Pályázati támogatás:T25582
OTKA
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4.

001-es BibID:BIBFORM084990
Első szerző:Mészáros Ilona (biológus)
Cím:Effects of supplemental UV-B radiation on photosynthesis performance and UV-B absorbing compounds in leaves of two oak species / Ilona Mészáros, Réka Láposi, Szilvia Veres, Éva Sárvári, Angéla Gáspár, Edit Bai, Viktor Oláh, Gyula Lakatos
Dátum:2005
ISSN:1588-385X
Megjegyzések:The aim of this work was to compare the photosynthetic responses of two tree species (Quercus petraea, Quercus robur) and to determine the leaf level protection under enhanced UV-B radiation in outdoor experiments. Three year old seedlings of both species were exposed to enhanced UV-B radiation (supplementing the ambient level with 40%) from bud break until leaf senescence. Under enhanced UV-B, increases of specific leaf mass (SLM) and reduction of leaf chlorophyll content per dry weight basis were observed but the total carotenoid content remained high. Both oak species responded with an increase of VAZ pool to enhanced UV-B. High values of potential photochemical efficiency of PS2 (Fv/Fm) were observed in both species during the growing season. On clear sunny days loss of Fv/Fm was observed from morning till midday which was larger under enhanced UV-B for both species suggesting that UV-B exposure enhanced the sensitivity of seedlings to photoinhibition. The enhanced UV-B induced increases in the amount of UV-B absorbing compounds in leaves of Q. robur but it slightly affected these traits of leaves of Q. petraea.
Tárgyszavak:Természettudományok Biológiai tudományok konferenciacikk
folyóiratcikk
UV-B radiation
Quercus
photochemical efficiency of PS2
xanthophyll cycle
flavonoids
Megjelenés:Acta Biologica Szegediensis. - 49 : 1-2 (2005), p. 165-166. -
További szerzők:Láposi Réka (1976-) Veres Szilvia (1972-) (biológus, biológia középiskolai tanár, angol-magyar szakfordító) Sárvári Éva Gáspár Angéla Bai Edit Oláh Viktor (1980-) (biológus) Lakatos Gyula (1949-) (ökológus)
Pályázati támogatás:INCO-Copernicus Project IC15-CT98-0126
Egyéb
National Research Foundation (No. 043646).
Egyéb
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5.

001-es BibID:BIBFORM085738
Első szerző:Mile Orsolya
Cím:Ecophysiological study on the salt tolerance of a pannonian endemism (Lepidium crassifolium (W. et K.) in inland saline area / O. Mile, I. Mészáros, Sz. Veres, G. Lakatos
Dátum:2002
ISSN:1588-385X
Megjegyzések:In the inland saline area two structurally different sands of Lepidio- Puccinellietum limosae community can be distinguised: open stand with low plant cover (mostly by Lepidium crassifolium) and closed stand with dense plant cover (mostly by Puccinellia limosa). The open habitat can be characterised by higher salinity degree. The leaf area of L. crassifolium is significantly lower on the open stand. The high water content per unit leaf area indicates the succulent character of the species and is involved in the avoidance of high salt (Na+) concentrations in the most saline habitat. There was remarkable accumulation of proline in leaves that can act as an osmotically active compound in the citoplasm. The osmotic potential of the tissue sap follows the changes of the proline concentrations, both diurnally and with the differences of habitats. Significant midday depression of Fv/Fm was found in the open habitat due to the unfavourable soil conditions and other additional abiotic factors such as higher irradiance and temperature.
Tárgyszavak:Természettudományok Biológiai tudományok konferenciacikk
folyóiratcikk
salt tolerance
Lepidium crassifolium
sodium
proline
osmotic potential
Megjelenés:Acta Biologica Szegediensis. - 46 : 3-4 (2002), p. 249-250. -
További szerzők:Mészáros Ilona (1952-) (biológus) Veres Szilvia (1972-) (biológus, biológia középiskolai tanár, angol-magyar szakfordító) Lakatos Gyula (1949-) (ökológus)
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6.

001-es BibID:BIBFORM082914
Első szerző:Oláh Viktor (biológus)
Cím:Cadmium-induced turion formation of Spirodela polyrhiza (L.) Schleiden / Viktor Oláh, Anna Hepp, Gyula Lakatos, Ilona Mészáros
Dátum:2014
ISSN:1588-385X
Megjegyzések:Spirodela polyrhiza (L.) Schleiden (giant duckweed) is an extensively studied representative of duckweeds (Lemnoideae subfamily, Araceae). Despite its widespread application in numerous research areas and well-known capability for producing turions, the effects of various toxicants on turion production are sporadically discussed in the scientific literature. Our aim was to study the growth of S. polyrhiza under cadmium stress and to test its potential interference with turion production. Effects of cadmium were assessed in axenic cultures of a local S. polyrhiza clone in 7-days-long duckweed growth inhibition tests. Our results indicated that higher cadmium concentrations decreased the relative growth rates of cultures within 3 days and growth inhibition reached its maximum between the 3rd and 5th days with 0.080 mg l-1 IC50. Parallel with slowed frond production - by mirror image pattern - induction of turion formation was observed. The first turions protruded by the 5th day of treatments in the 0.075-0.75 mg l-1 concentration range. Such rapid onset of turion formation is indicative of an almost immediate switch between normal and turion mode of meristem function upon cadmium stress. The consideration of this mechanism in practical applications of S. polyrhiza is recommended.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény hazai lapban
folyóiratcikk
Megjelenés:Acta Biologica Szegediensis. - 58 : 2 (2014), p. 103-108. -
További szerzők:Hepp Anna (1991-) (biotechnológus) Lakatos Gyula (1949-) (ökológus) Mészáros Ilona (1952-) (biológus)
Pályázati támogatás:TÁMOP-4.2.2.B-10/1
TÁMOP
TÁMOP-4.2.3-12/1/KONV-2012-0048
TÁMOP
TÁMOP 4.2.4. A/2-11-1-2012-0001
TÁMOP
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7.

001-es BibID:BIBFORM085740
Első szerző:Veres Szilvia (biológus, biológia középiskolai tanár, angol-magyar szakfordító)
Cím:Interspecific variations of photochemical properties in a xerotherm grassland community / Sz. Veres, O. Mile, R. Láposi, G. Lakatos, I. Mészáros
Dátum:2002
ISSN:1588-385X
Megjegyzések:In this work the role of xanthophyll cycle and its relation to the photosynthetic activity in the dominant species of a semiarid sandy grassland community (PotentilloFestucetum pseudovinae) were studied during the stressful summer period. The total amount of xanthophyll cycle pigments (violaxanthin, anteraxanthin, zeaxanthin) related to total chlorophyll content (VAZ pool) showed considerable interspecific alterations and it was 2-3 times larger in the summer period than in spring. The changes in the xanthophyll cycle, the potential (Fv/Fm) and actual photochemical efficiency (?F/Fm') of PSII, as well as, the results of parallel measurements on their daily dynamics show that zeaxanthin has a major role in the photoinhibition in the photosynthetic apparatus during the summer stress on sandy grassland species. In July, the decreases of Fv/Fm was accompanied with increases of NPQ at the 100-120% extent depending on the species.
Tárgyszavak:Természettudományok Biológiai tudományok konferenciacikk
folyóiratcikk
chlorophyll fluorescence
non-photochemical quenching (NPQ)
photochemical efficiency of PSII
semiarid grassland
xanthophyll cycle
Megjelenés:Acta Biologica Szegediensis. - 46 : 3-4 (2002), p. 237-238. -
További szerzők:Mile Orsolya Láposi Réka (1976-) Lakatos Gyula (1949-) (ökológus) Mészáros Ilona (1952-) (biológus)
Pályázati támogatás:6196
OTKA
26188
OTKA
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8.

001-es BibID:BIBFORM085007
Első szerző:Veres Szilvia (biológus, biológia középiskolai tanár, angol-magyar szakfordító)
Cím:Variation in ecophysiological traits of dominant species in open and closed stands of a semiarid sandy grassland / Szilvia Veres, Orsolya Mile, Réka Láposi, Gyula Lakatos, Ilona Mészáros
Dátum:2005
ISSN:1588-385X
Megjegyzések:Under the continental climate of the Carpathian Basin, semiarid grasslands represent one of the widespread vegetation types. Due to overgrazing and other disturbances, most of the semiarid grasslands in Hungary are the mosaics of more or less degraded patches. Our work has focused on the variations in the ecophysiological traits of the common dominant species in a moderately degraded (vegetation cover 70%) and a strongly degraded stand (vegetation cover 27%) of Potentillo-Festucetum pseudovinae community. As a result of low soil moisture content, species experienced significantly higher leaf water saturation deficit in the open stand. Carotenoid pool was larger for all the species in the strongly degraded stand. The protective xanthophyll cycle pool was also higher in the strongly degraded stand, and reached 30?33% of the total carotenoid content. The potential photochemical efficiency (Fv /Fm) was lower for monocot species. There was a decrease in the Fv /Fm values at noon, which was larger in the strongly degraded stand.
Tárgyszavak:Természettudományok Biológiai tudományok konferenciacikk
folyóiratcikk
semiarid grassland
degraded stands
carotenoids
xanthophyll cycle
photochemical activity
Megjelenés:Acta Biologica Szegediensis. - 49 : 1-2 (2005), p. 175-176. -
További szerzők:Mile Orsolya Láposi Réka (1976-) Lakatos Gyula (1949-) (ökológus) Mészáros Ilona (1952-) (biológus)
Pályázati támogatás:No 6196
OTKA
No 26188
OTKA
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