The effects of UV-C radiation on the germination rate and fungal contamination of tall fescue seeds were investigated. Samples from the same seed lot were irradiated in two different ways in two consecutive years. The seeds were irradiated with a Hg vapour lamp using different doses. In the first trial one side of the seeds was irradiated, while in the second trial a mirror was used to irradiate the whole seed surface. The results showed that various doses of UV-C irradiation had an effect on the germination rate, but there were no significant differences in germination percentage between the treatments. Differences in fungal contamination rates were observed when the seeds were irradiated on all sides. The presence of 21 fungal genera was identified on the seeds, the saprotrophic fungi
We examined effects of UV and visible light irradiation on mycelial growth and sclerotium formation of Sclerotinia sclerotiorum. The irradiation with UV had no effect on the production of sclerotia. However it had strong inhibitory action on the growth of mycelia. In cultures of the fungus irradiated with yellow and green light more but small sclerotia developed mainly in the perimeter of culture at the time of irradiation and between this circle and the wall of Petri dishes. In cultures irradiated with red and blue light, a few, but large sclerotia developed.
Authors:P. Nagy, A. R. Thompson, M. Schultz and P. Solymosi
Mixed population of different biotypes of C. arvense can be found in the cereal fields in Eastern Europe. Three biotypes were identified taxonomically: var. arvense; var. horridum, and var. vestitum. Out of the three identified biotypes, only var. arvense showed more sensitivity to chlorsulfuron, while the other two biotypes were less sensitive. There was no difference in the germination behaviour of the biotypes, thus all varieties can be present on the field at the same time. The less sensitive biotypes have a thicker cuticle and less stoma on the leaves than the more sensitive one. There is no significant difference between sensitive and resistant biotypes in absorption and translocation of the 14C chlorsulfuron and florasulam. Sensitivity of the ALS-enzyme was significantly reduced in the resistant biotypes, although the enzyme still functions. Since that cereal fields in Eastern Europe are infested with C. arvense biotypes with different susceptibilities to chlorsulfuron, it is important to consider resistance management when selecting herbicides. Selection pressure for ALS resistance can be reduced by including other herbicides with an alternative mode of action; as tank mixes, premixes, or separate applications.
Authors:Margit Pál, Kata Varga, Olga Nagy and P. Deák
The anaphase promoting complex or cyclosome (APC/C) is a large protein complex with an ubiquitin ligase activity which specifically targets mitotic regulatory proteins for proteasomal degradation. The APC/C contains at least 11 subunits, most of which are evolutionarily conserved from yeasts to humans. We have isolated and characterized mutant alleles of the gene that codes for the APC10/Doc1 subunit of the
APC/C. Loss of function
mutants have rudimentary imaginal discs and arrest their development as prepupae. Larval neuroblasts from these mutants show gross mitotic defects including high mitotic index, chromosome overcondensation, metaphase-like arrest and frequent aneuploid and polyploid cells. Mitotically arrested cells accumulate one of the main substrates of APC/C, cyclin B, most likely due to disabled ubiquitination activity. Our results suggest that the Apc10/Doc1 subunit has an essential role in establishing E3 ubiquitin ligase activity of APC/C in
Authors:P. Makleit, A. Nagy, S. Veres and A. Fónagy
The concentration (in mg kg–1 fresh weight) of two main hydroxamates, 2,4-dihydroxy- 7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), and their temporal changes were simultaneously investigated using HPLC analysis in the leaves and roots of five Pioneer® maize (Zea mays L.) hybrids to select hybrids with higher hydroxamate contents. Although significant differences were found among hybrids in leaves, youngest leaves and roots, none of them showed unambiguously higher hydroxamate contents. However, the age of the organs and the plants significantly affected hydroxamate content. DIMBOA content of leaves decreased with increasing organ and plant age. DIBOA content varied among the hybrids, but generally decreased in the initial phase and then increased. In the roots, DIMBOA content decreased during the 21-day study and although DIBOA content did not show a clear temporal tendency, differences among hybrids were detected. According to current results, hydroxamate content temporally decreases in hybridspecific patterns, which should be considered when establishing a proper sampling time frame.
Authors:Renáta Petrikovszki, Franciska Tóthné Bogdányi, F. Tóth and P. Nagy
Few researches address the compatibility of organic mulching and entomopathogenic (EPN) and slug-parasitic (SPN) nematodes, although organic mulching may provide favourable conditions for these beneficial organisms. Our aim was to examine the effect of different concentrations (0.1, 0.5, 1 and 5%) of aqueous extracts of green waste compost, the dry leaf litters of the common walnut (Juglans regia) and Norway maple (Acer platanoides) on EPN (Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, Steinernema kraussei) and SPN (Phasmarhabditis hermaphrodita) species. Experiments were set up in 96-well, flat-bottom microplates. After a 24-hour exposure time, the number of dead animals was counted under a transmission microscope. Green waste compost extracts caused quite low or no mortality in case of all examined species. Mortality caused by the 5% Norway maple leaf litter extract was moderate (34.6%) in the case of S. carpocapsae juveniles, while 100% of juveniles of other species died. The highest (5%) concentration of the common walnut leaf litter extract caused 100% mortality in all species. As a conclusion, green waste compost mulch seems to be more compatible with EPN and SPN species than common walnut or Norway maple leaf litter mulch.
Authors:P. Nagy, G. Bakonyi, E. Péli, I. Sonnemann and Z. Tuba
Long-term effects of the elevated atmospheric CO
on biosphere have been in focus of research since the last few decades. In this experiment undisturbed soil monoliths of loess grassland were exposed to an elevated CO
environment (two-times the ambient CO
level) for a period of six years with the aid of the open top chamber method. Control without a chamber and CO
elevation was applied as well. Elevated CO
level had very little impact on soil food web. It did not influence either root and microbial biomass or microbial and nematode community structure. The only significant response was that density of the bacterial feeder genus
increased in the chamber with elevated CO
concentration. Application of the open top chambers initiated more changes on nematodes than the elevated CO
level. Open top chamber (OTC) method decreased nematode density (total and plant feeder as well) to less than half of the original level. Negative effect was found on the genus level in the case of fungal feeder
, plant feeder
. It is very likely that the significantly lower belowground root biomass and partly its decreased quality reflected by the increased C/N ratio are the main responsible factors for the lower density of the plant feeder nematodes in the plots of chambers. According to diversity profiles, MI and MI(2–5) parameters, nematode communities in the open top chambers (both on ambient and elevated CO
level) seem to be more structured than those under normal circumstances six years after start of the experiment.
Authors:A. Nagy, G. Bán, F. Tóth, P. Zrubecz and K. Szemerády
Western flower thrips,
(Pergande) (Thysanoptera: Thripidae) is one of the most important pests of greenhouse pepper in Hungary. It has a hidden lifestyle, a short generation interval and a high reproductive rate. Due to these characteristics it is difficult to obtain an effective, environment-friendly and harmless control of the pest. Previous studies have shown that under caged plant conditions, the common crab spider,
(Thorell) (Araneae: Thomisidae) is effective against western flower thrips. In this study, we examined some of the technological questions of the use of spider larvae.We investigated the necessary amount and number of applications of spider larvae under caged plant conditions. The efficiency of spiders at the whole greenhouse level was also studied. While the ratio of damaged surface of peppers treated with
was significantly lower than that of non-treated plants, increasing the amount of spider larvae did not improve the effectiveness of thrips control. Although whole greenhouse experiences showed a similar, significant decrease in the rate of damaged surface in the case of peppers treated with spider larvae, when compared to untreated control; the efficiency of spiders remained below the level of economic acceptance.
Authors:Á. Horváth, P. Sántha, V. Horváth, Nóra Török, I. Nagy, G. Jancsó, Cs. Vágvölgyi and F. Somogyvári
A new, rapid method is described which permits the genotyping of genetically modified animals from a microlitre volume of whole blood samples via one step polymerase chain reaction amplification. The major advantage of the presented method is the exclusion of a DNA preparation step, which significantly reduces the time expenditure and work load of the genetic testing. Pilot studies indicate, that this method is efficient and applicable also on tissue biopsies and larger amount of blood providing a rapid and reliable new technique over conventional genotyping approaches.