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Zucchini yellow mosaic potyvirus (ZYMV)was isolated in Hungary from cucumber for the first time in 1995 and now it is widespread causing devastating epidemics in cucurbit crops. Four isolates were chosen from different cucurbit plants collected in 1995 and 1999 and mole- cular variability of N-terminal region of coat protein was studied.Hungarian isolates show lower molecular variability within themselves than with ZYMV isolates from other geographical origins.Hungarian isolates have amino acid sequences specific only to them that suggest common ancestor.

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Total mineral uptake capacity of zucchini (Cucurbita pepo L. cv. giromontiina) grown in an experimental field at Gödöllő was studied. The mineral content of the soil (brown acidic sandy forest soil) showed unexpectedly high content (mg kg−1 DW) of Ba (95.5), Cr (32.9), Ni (27.8), Pb (15.4) and Zn (53.3). Boron (B) concentration of the soil was relatively low (7.1 mg kg−1 DW), but its bioaccumulation content in root, (2.5) shoot, (33.1) and leaf (50.1) tissues of the plant (mg kg−1 DW). Zinc (Zn) was also bioaccumulated in the plant with contents (mg kg−1 DW) of 47.1 (roots), 23.0 (shoots) and 56.1 (leaves) as compared with 53.3 (in the soil). Toxic element exclusion was observed in zucchini (mg kg−1 DW) concerning Ba (29.0), Co (0.2), Cr (5.3), Ni (5.8) and Pb (3.4) measured in the roots when compared with their concentrations in the soil: Ba (95.5), Co (10.2), Cr (32.9), Ni (27.8) and Pb (15.4). In silico sequence analyses of nucleotide and amino acid sequences of aquaporins (NIP, TIP, SIP and Si-TRP), boron-exporters (BOR), and rbcL of cpDNA revealed plant species with high sequence similarities to the sequences of Cucurbits, which predicted additional plants with intensive mineral (B and Zn) uptake capacity, similar to Cucurbits with phytoextraction potential.

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Pumpkin, squash and zucchini are important vegetable crops in tropical and temperate regions. The development of genetic transformation methods offers the potential of introducing valuable traits into these crops. An efficient in vitro plant regeneration system is a critical point for genetic manipulation. The regeneration ability of three Cucurbita varieties was tested on Murashige and Skoog medium supplemented with different growth regulators. Cotyledons of all the varieties were cultured to investigate the effect of 2,4-D (0, 1, 2, 3, 4 mg l −1 ) with or without KIN (0, 0.5, 5 mg l −1 ) and of BA (0, 1, 1.2 mg l −1 ) combined with IAA (0, 0.9, 1, 1.2 mg l −1 ), on the efficiency of shoot induction. Abscisic acid (0.26 mg l −1 ABA) was also added to one medium. To find the most suitable combination for shoot induction, cotyledon segments of the three varieties were also cultivated on media with different concentrations of BA (0–1.2 mg l −1 ) and IAA (0–0.9 mg l −1 ). Shoot induction was achieved via organogenesis in the tested varieties. Leafy shoots were transferred to root induction media. Regenerated plantlets with roots were transferred to sterile soil. This is the first report on in vitro regeneration from cotyledon explants of the pumpkin cultivar Nagydobosi and the pattypan squash cultivar Óvári fehér.

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The uptake of persistent organic pollutants (POPs) from soil by plants allows the development of phytoremediation protocols to rehabilitate contaminated areas. In this study theoretical descriptors have been employed as independent variables for developing quantitative structure-activity relationship (QSAR) models for predicting the bioconcentration factors (BCFs) of POPs in different plants. A quantitative estimation has been given on the molecular properties of POPs in terms of theoretical molecular descriptors that are relevant to the uptake from soil and pharmacokinetic behavior in plants. The study resulted in statistically significant linear regression models developed for the BCF values of 20 polychlorinated dibenzo-p-dioxins/dibenzofurans and 14 polyhalogenated biphenyls in two zucchini varieties based on retrospective data. The parameters have been selected from a set of 1660 DRAGON, 150 VolSurf and 11 Quantum Chemical descriptors. The best regression model (Eq. 1), employing VolSurf, DRAGON GETAWAY and quantum chemical descriptors, displayed the following highly significant statistical parameters: n=27, R 2=0.940, SE=0.155, F=392.1, q 2=0.922; external validation set: n=7, R2=0.739, q2=0.47, SE=0.338, F=14.2 It is suggested that the QSAR models proposed might contribute to the development of workable soil remediation strategies.

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The aim of our study was to investigate the susceptibility of some Chenopodium species (Chenopodium album, C. glaucum, C. berlandieri, C. ugandae) to six viruses (Alfalfa mosaic virus, Cucumber mosaic virus, Obuda pepper virus, Potato virus Y, Sowbane mosaic virus, Zucchini yellow mosaic virus). Fourteen plants of each species were mechanically inoculated and virus susceptibility was evaluated on the basis of symptoms and back inoculation. A series of new host-virus relations were determined.

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(1899) 573–587. Zucchini, A. – Lourenço, P. B.: A micro-mechanical model for the homogenisation of masonry. International Journal of Solids and Structures Vol. 39 (2002) 3233–3255. Zucchini, A

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Acta Alimentaria
Authors:
Sz. Szabó
,
Zs. Németh
,
É. Polyák
,
I. Bátai
,
M. Kerényi
, and
M. Figler

Sprouts contain minerals, vitamins, and other compounds, which may have antimicrobial activity. Antimicrobial compounds are released from homogenized sprouts and diffuse into the culture medium inhibiting the growth of pathogenic bacteria. These antibacterial compounds may influence the multiplication of contaminating pathogens. In this study the antimicrobial effects of 55 different homogenized sprouts were investigated with agar well diffusion method on human pathogenic bacteria. Homogenizates of different radish, early kohlrabi, and red cabbage sprouts caused inhibitory zone around the wells on the surface of inoculated agar plates. Mustard, zucchini, medical (German) chamomile, spicy fenugreek, and adzuki bean sprouts had antimicrobial effect only against a few human pathogenic bacteria. Twenty-nine other spicy and vegetable sprouts had no antibacterial activity against the investigated human pathogens. The results suggest that a few sprouts have antimicrobial properties, but different cultivars of the same species have different effects against different bacterial strains. The sprouts of radish cultivars contained the most effective antibacterial compounds.

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Thiols are known to play crucial roles in plant defense responses, e.g. against pathogens. In the present study, the efficiency of these molecules was evaluated in regenerated Cucurbita pepo L. subsp. pepo var. styriaca Greb. plants in response to compatible Zucchini yellow mosaic virus infection. Thiol contents were modulated by applying the cysteine precursor L-2-oxothiazolidine-4-carboxylic acid (OTC) to callus cells. Cytological and biochemical methods were used for determination of glutathione within callus cells and leaves of plants regenerated via somatic embryogenesis. Reduced glutathione levels (GSH) significantly increased in callus cells one week after 1.0 mM OTC treatment by about 56% and resulted in enhanced GSH levels throughout the investigation period of 13 weeks. Three weeks after ZYMV infection untreated plants regenerated from callus culture exhibited stunted growth forms, yellowing, mosaic and blistering on the leaves whereas 68% of 1.0 mM OTC pretreated regenerated plants were characterized by a complete absence of symptoms. Treatment with OTC stimulated the synthesis, conversion and translocation of thiols during advanced ZYMV infection. Compared to untreated infected leaves, a graduate increase in cysteine (cys) and γ-glutamyl-cysteine (γ-glucys) contents was measured in 0.5 mM and 1.0 mM OTC treated older leaves, whereas total glutathione (tGSH) decreased significantly after infection. In OTC treated younger leaves cys and tGSH concentrations remained at control levels and were unaffected by ZYMV. In contrast, OTC treatment caused a dramatic induction of γ-glucys, up to 191% in younger infected leaves. The results show that altered levels of thiols by OTC were accompanied by enhanced tolerance against ZYMV, suppression of ZYMV induced symptoms as well as delayed symptom development.

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Acta Phytopathologica et Entomologica Hungarica
Authors:
E. Kiss
,
G. Kazinczi
,
J. Horváth
,
S. Kobza
,
T. Baranyi
,
M. Varga
,
B. Havasréti
, and
A. Fehér

Viruses caused severe yield losses of field cucumber in Hungary last years. Field surveys have been carried out on field cucumber to evaluate virus infection in the region of Gyor-Moson-Sopron county. Virus infection was determined on the basis of symptoms, biotest and with DAS-ELISA serological method for the presence of 15 viruses. The virus vector aphid flight was monitored by Moericke yellow water pan. On the basis of field surveys 100% virus infection has been observed in cucum­ber fields. Virus symptoms were various, depending on varieties, environ­men­tal factors, viruses and strains. Out of the viruses investigated only three [Cucumber mosaic cucumovirus (CMV) (DTL serotype); Zucchini yellow mosaic potyvirus (ZYMV) and Watermelon mosaic 2 potyvirus (WMV-2)] have been occurred on cucumber samples. Biological tests confirm­ed the results of DAS-ELISA. There was much difference, regarding the frequency of viruses. ZYMV was dominant in 1998, while CMV was dominant in 1999. The proportion of the complex infection was very high. Till now, besides CMV other viruses cannot be detected from weeds in cucumber ecosystems. The peak of aphid flight was in the middle of June and later a secondary peak was observed at the beginning of July, which coincided with the appearance of the first virus symptoms. Regarding, that cucumber production occurs in fields at the same place year by year, soil borne virus vectors may play important role in virus infection. To reduce virus infection we can suggest using of light summer oils, which prevents virus transmission by aphids. It is concluded that team work of virologists, pathologists, growers, technologists and the breeders is necessary to solve virus problems of field cucumber in Hungary.

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] Szucs M. : Föld- és vályogfalú házak építése és felújítása . Építésügyi Tájékoztatási Központ Kft. , Budapest 2002 . [17] Zucchini

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