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001-es BibID:	BIBFORM056052
Első szerző:	Demeter Zita (biológia-kémia szakos tanár)
Cím:	Osmotic stress responses of individual white oak (Quercus section, Quercus subgenus) genotypes cultured in vitro / Zita Demeter, Péter Kanalas, Csaba Máthé, Klára Cseke, Erzsébet Szőllősi, Márta M-Hamvas, Katalin Jámbrik, Zoltán Kiss, Ilona Mészáros
Dátum:	2014
ISSN:	0176-1617
Megjegyzések:	White oaks (Quercus section, Quercus subgenus) are widely distributed in Europe. Quercus petraea (sessile oak), an economically important species is predicted to be affected by climate change. Q. pubescens (pubescent oak) and Q. virgiliana (Italian pubescent oak) are economically less important, drought tolerant species. Frequent hybridization of white oaks was observed and currently the introgression of Q. pubescens and Q. virgiliana in non-mediterranean regions of Europe has been reported. Our goal was to use tissue cultures established from individual trees of the above taxa and their putative hybrids, all present in the forest stand of Síkfőkút LTER Research Area (NE Hungary) as simple experimental model systems for studying drought/osmotic stress tolerance. Tissue cultures are more suitable models for such studies, than seedlings, because they are genetically identical to the parent plants. Polyethylene glycol (PEG6000) treatments were used for this purpose. The identification of taxa was based on leaf morphological traits and microsatellite analysis and showed that Q. petraea is genetically distinct to all other taxa examined. We established six callus lines of Quercus. As expected, in Q. petraea cultures PEG6000 induced severe loss of fresh weight and the ability to recover after removal of the osmoticum, which was not characteristic for Q. pubescens and Q. virgiliana. Putative hybrids exhibited an intermediate response to osmotic stress. Activity gels showed the increase of single-strand preferring (SSP) nuclease and no significant change of guaiacol-peroxidase activities in drought-sensitive genotypes/cultures and no significant increase of SSP nuclease activities accompanied with increases of guaiacol-peroxidase activities in drought-tolerant ones. This indicates that drought/osmotic stress tolerance is associated to increased capacity of scavenging reactive oxygen species and hence less susceptibility to DNA damage. Our results confirm that tissue cultures of oak are suitable model systems for studying drought/osmotic stress responses.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Quercus Osmotic Stress in vitro
Megjelenés:	Journal Of Plant Physiology. - 171 : 2 (2014), p. 16-24. -
További szerzők:	Kanalas Péter (1983-) (biológus) Máthé Csaba (1966-) (biológus) Cseke Klára Szőllősi Erzsébet (1983-) (biológus) Mikóné Hamvas Márta (1963-) (biológus) Jámbrik Katalin Kiss Zoltán Mészáros Ilona (1952-) (biológus)
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001-es BibID:	BIBFORM030985
Első szerző:	Mészáros Ilona (biológus)
Cím:	Diurnal and seasonal changes in stem radius increment and sap flow density indicate different responses of two co-existing oak species to environmental stress / Ilona Mészáros, Péter Kanalas, András Fenyvesi, József Kis, Balázs Nyitrai, Erzsébet Szőllősi, Viktor Oláh, Zita Demeter, Ágnes Lakatos, István Ander
Dátum:	2011
ISSN:	1786-691X 1787-064X
Megjegyzések:	Using continuous monitoring of stem radius combined with sap flow measurements weassessed the effects of environmental conditions on tree radial growth and water status of two coexistingoak species (Quercus petraea and Quercus cerris) at high resolution time in growingseasons of 2008 and 2009. The forest (95?100 yr) is situated in a xeric site in the transition zonebetween forested and forest-steppe regions in north-eastern Hungary, Bükk mountains (47o90'N,20o46'E, elevation 320?340 m a.s.l.). Weather conditions in the growing season of 2008 (totalrainfall 354 mm, mean daily temperature 17.0 oC) was less extreme than in 2009 (total rainfall299 mm, temperature 17.9 oC). Rainfall strongly determined the course of radial growth incrementin trees. Radial growth of trees was limited in 2009 due to the drought in spring. The maximumradial increment of both species was achieved three weeks earlier (4th week of June) than in 2008(4th week of July). We used dendrometer monitoring data for estimation of stem (tree) waterdeficit ( W) by measuring water-related changes in stem radius (Zweifel et al. 2005). Themagnitude of tree water deficit variation ( W) was always smaller in Q. cerris than in Q. petraea.In contrast, Quercus cerris always exhibited larger daytime averages and maxima of sap flowdensity. In August of 2009 when drought became severe there were larger increases in tree waterdeficit ( W) (50?55 %) in both species compared to July as it could be expected from the extentof decreases in sap flow density (24?28%). Our data suggested that due to the low SWC thetranspiration was supported mainly from the inner water storage of trees during prolonged droughtwhich resulted in high stem water deficit ( W).
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény hazai lapban Doktori Iskola drought forest potential evapotranspiration Quercus petraea Quercus cerris stem (tree) water deficit
Megjelenés:	Acta Silvatica et Lignaria Hungarica. - 7 (2011), p. 97-108. -
További szerzők:	Kanalas Péter (1983-) (biológus) Fenyvesi András Kis József Nyitrai Balázs (1987-) (ökológus) Szőllősi Erzsébet (1983-) (biológus) Oláh Viktor (1980-) (biológus) Demeter Zita (1985-) (biológia-kémia szakos tanár) Lakatos Ágnes Ander István
Pályázati támogatás:	TÁMOP-4.2.2/B-10/1-2010-0024 TÁMOP Juhász-Nagy Pál Doktori Iskola
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