György Végvári

Direct photothermal techniques for rapid quantification of total anthocyanin content in sour cherry cultivars

The analytical performance of the newly proposed laser-based photoacoustic spectroscopy (PAS) and of optothermal window (OW) method for quantification of total anthocyanin concentration (TAC) in five sour cherry varieties is compared to that of the spectrophotometry (SP). High performance liquid chromatography (HPLC) was used to identify and quantify specific anthocyanins. Both, PAS and OW are direct methods that unlike SP and HPLC obviate the need for the extraction of analyte. The outcome of the study leads to the conclusion that PAS and OW are both suitable for quick screening of TAC in sour cherries. The correlation between the two methods and SP is linear with R(2)=0.9887 for PAS and R(2)=0.9918 for OW, respectively. Both methods are capable of the rapid determination of TAC in sour cherries without a need for a laborious sample pretreatment.

Investigation of tissue structure and xylem anatomy of eight rootstocks of sweet cherry (Prunus avium L.)

Reduction of crop yield from high water stress is a serious agricultural problem worldwide, which is expected to intensify under future global change scenarios. Efforts are underway worldwide to improve crops resistance to drought. One possible way is the careful choice of rootstock-scion combination. It is well known that water stress symptoms of grafted cherry trees to a large extent depend on the rootstock variety. Scions grafted on dwarf rootstocks show more serious stress symptoms, so it is reasonable to hypothesize that these symptoms and the tissue structure of the rootstock stem are connected. This paper examines this connection for 1-year-old seedlings of eight cherry rootstocks with different degree of vigor. Tissue structure was observed via scanning electron microscope images. Investigations were focused on number, size, and distribution of vessels, because they are principally responsible for water transport. Stem porosity (i.e., the total vessel area relative to the stem area, in cross-sectional view) of the dwarfing rootstocks was found to be significantly smaller than that of the others, supporting the notion that stem anatomical characteristics might contribute to water stress sensitivity.

The arbuscular mycorrhizal host status of plants can not be linked with the Striga seed-germination-activity of plant root exudates

Root exudates from sorghum, a Striga and arbuscular mycorrhizal fungal (AMF) host plant, and a number of Striga non-host plants which are AM host or AM non-host plants were collected and their effect on seed germination of Strigahermonthica was tested. Striga seeds germinate exclusively in presence of strigolactones, thus, Striga seeds germination is an indicator for the presence of strigolactones. Strigolactones are also thought to be essential signals (branching of AMF) for a successful root colonization by AMF. Root exudates of AM host plants stimulated Striga seed germination or showed no effect, whereas root exudates of AM non-host plants never showed an effect on Striga seed germination. This means that Striga seed germination stimulation by compounds in root exudates can not necessarily be linked with the host and nonhost status of plants to AMF. This absence of an effect on Striga seed germination of root exudates of AM host plants can be linked i) either with different levels of strigolactones in the root exudates of different AM host plants or ii) with the fact that not the same compounds are involved in Striga seed germination and in signaling during the establishment of the AM symbiosis.ZusammenfassungWurzelexsudate von Sorghum-Hirse, einem Wirt der parasitischen Samenpflanze Striga und von arbuskulären Mykorrhizapilzen (AMP), sowie einer Reihe von Nichtwirten von Striga, die entweder Wirte oder Nichtwirte von AMP sind, wurden gesammelt und ihre Wirkung auf die Samenkeimung von Striga hermonthica untersucht. Striga-Samen keimen nur in Gegenwart von Strigolactonen, weshalb ihre Keimung als Indikator für Strigolactone dient. Strigolactone gelten daneben als essenzielle Signale für eine erfolgreiche Wurzelbesiedlung durch AMP. Wurzelexsudate von AMP-Wirten stimulierten zum Teil die Keimung von Striga-Samen, während Wurzelexsudate von AMP-Nichtwirten niemals die Samenkeimung anregten. Dies bedeutet, dass die Stimulierung der Samenkeimung bei Striga durch Komponenten von Wurzelexsudaten keinen Rückschluss auf den Wirtsstatus von Pflanzen gegenüber AMP erlaubt. Die fehlende Wirkung der Wurzelexsudate von AMP-Wirten auf die Samenkeimung von Striga kann entweder auf i) der unterschiedlichen Konzentration von Strigolactonen in den Wurzelexsudaten von AMP-Wirtspflanzen beruhen oder ii) darauf, dass nicht dieselben Exsudatkomponenten für die Samenkeimung und als essenzielle Signale für die AMP-Besiedlung von Wurzeln verantwortlich sind.

Rutin in buckwheat grain meal determined by UV photoacoustic spectroscopy and HPLC

Abstract A relatively novel approach for easy and quick determination of rutin in buckwheat grain is suggested. The rutin content of the grain in seven common buckwheat (Fagopyrum esculentum) and six Tartary buckwheat (Fagopyrum tataricum) varieties was investigated by means of UV photoacoustic spectroscopy and HPLC as reference method. The lowest content was found in ‘Botan’ and ‘Bamby’ varieties, while the highest values were obtained in the variety ‘Emka’. Rutin content in grain of all Tartary buckwheat varieties was two orders of magnitude higher than in the other varieties. Rutin content in F. esculentum ranges between 9 and 36 mg/100 g dry weight as compared to 921 to 2 132 mg/100 g dry weight in F. tataricum. The UV photoacoustic spectroscopy data show rather good correlations of R2=0.977 and R2=0.980 with values obtained by HPLC data for all measured samples. Therefore, UV photoacoustic spectroscopy can be a cheap and quick method for determining rutin content in buckwheat grain.

Einfluss der Unterlage auf Wuchs, Ertrag und Fruchtqualität von Süßkirschen (Prunus avium L.) der Sorten ‘Regina’ und ‘Kordia’ im Nachbau in Ostösterreich

ZusammenfassungIn einem siebenjährigen Feldversuch (2006–2012) in der Versuchsanlage der Universität für Bodenkultur in Wien wurde der Einfluss unterschiedlicher Unterlagen (‘Gisela 5’, ‘Gisela 6’, ‘PHL-C’, ‘Piku 1’, ‘Weiroot 158’) auf Wuchs- und Ertragsparameter der Süßkirschensorten ‘Regina’ und ‘Kordia’ untersucht, von 2010–2012 auch auf innere und äußere Fruchtparameter. Die Veredlungen auf ‘Gisela 6’ zeigten den stärksten Wuchs und Einzelbaumertrag von allen Unterlagen. ‘Weiroot 158’ und ‘PHL-C’ wuchsen stärker als ‘Gisela 5’ und ‘Piku 1’ und hatten ähnliche Einzelbaumerträge, demnach aber einen geringeren spezifischen Ertrag. ‘Gisela 5’ und ‘Piku 1’ wiesen den höchsten spezifischen Ertrag, ‘Piku 1’ allerdings zum Teil auch ein geringeres Einzelfruchtgewicht als die anderen Unterlagen auf. Bei der Fruchtqualität gab es keine gravierenden Unterschiede. Aufgrund dieser Ergebnisse kann ‘Gisela 5’ für diesen Standort auch für den Nachbau nach Kirschen als geeignete schwach bis mittelstark wachsende Unterlage eingestuft werden, und zwar günstiger als die im Wuchs vergleichbare Unterlage ‘Piku 1’. Auf noch trockeneren und schwach wüchsigen Standorten dürfte ‘Gisela 6’ besser geeignet sein als die bei uns im Vergleich zu ‘Gisela 5’ getesteten etwas stärker wachsenden Unterlagen ‘Weiroot 158’ und ‘PHL-C’.AbstractIn a 7 year field trial (2006–2012) in the research orchard of the University in Vienna the influence of five different dwarfing (‘Gisela 5’, ‘Piku 1’ and ‘PHL-C’) and semi-dwarfing (‘Gisela 6’ and ‘Weiroot 158’) rootstocks on growth and yield of the sweet cherry cultivars ‘Kordia’ and ‘Regina’ were investigated, and from 2010–2012 also the internal and external fruit quality was assessed. The trees grafted on ‘Gisela 6’ showed the strongest vigor and the highest single tree yield. ‘Weiroot 158’ and ‘PHL-C’ were growing more than ‘Gisela 5’ and ‘Piku 1’ and had nearly the same single tree yield; therefore, they were lower in the specific yield. ‘Gisela 5’ and ‘Piku 1’ had the highest specific yield, however, ‘Piku 1’ also in 2 years a lower single fruit weight than other rootstocks. There were only marginal differences in the fruit quality characteristics. Summarizing our results, ‘Gisela 5’ can be recommended as dwarfing rootstock also in a replanting orchard for our conditions. If the soil and growing conditions are more challenging, ‘Gisela 6’ could be more suitable than the compared to ‘Gisela 5’ tested more vigorous growing rootstocks ‘Weiroot 158’ und ‘PHL-C’.