Stand and leaf scale responses of loess grassland swards to elevated air CO
concentration had been investigated in a mini FACE system during 1998–2000. The study concentrated on biomass, leaf area index (LAI) and vegetation surface temperature (stand scale) and on diurnal carbohydrate pattern and gas-exchange responses (leaf scale). Leaf net CO
uptake under prolonged exposure to elevated CO
showed an upward response in the dicotyledonous and a downward one in the monocotyledonous species. Dawn and evening carbohydrate levels in leaves suggested growth stimulation of the dicot under elevated CO
and the opposite for the grass species and indicated sink limitation as a major factor determining photosynthetic acclimation at the species level. The smaller LAI as well as the insignificant biomass response to elevated air CO
was a compounded response by multi-species stands. Under mild water shortage, elevated air CO
concentration partly alleviated the drought effect shown by the higher relative growth rate of LAI. Canopy surface temperatures of the vegetation in the CO
enriched rings were higher than those in the ambient rings suggesting that decreased leaf conductance and transpiration were responsible for the temperature difference between the treatments. Increased canopy surface temperature under elevated air CO
concentration will probably lead to increased sensible heat flux and therefore enhanced convection at larger spatial scales.
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
The aim of the present work was to study the soil seed bank of the semiarid sandy grassland community using the nested sampling procedure. The samples consisted of six concentric cores with diameters ranging from 5 to 22 cm and surface area ratio of the outermost to the innermost ring of 19. Investigations were directed to establish the minimum core diameter to find the dominant and less frequent species in the seed bank and also to have an insight on distribution patterns of species. The smallest core (diameter: 5 cm) employed in 20 repetitions was adequate to find the dominant species in the seed bank, while increasing the sample area to 19 times resulted in doubling the number of species found. The seeds of the dominant species had clustered distribution even at the smallest applied sample scale, while patterns of seed clumps followed different (uniform, contagious, random) distributions.
The survey was carried out on the seed bank of several patches of an open, semiarid sandy grassland (Festucetum vaginatae Rapaics ex Soó 1929 (Borhidi 1996)). We chose four, approximately 20 m × 20 m large, adjacent patches, different in their species composition and total cover. Soil samples were taken in early spring and at the end of summer, in two consecutive years. We determined the seed bank of the samples with the seedling emergence method. The fact that we found the seeds of only two species that were not present in the vegetation indicates the isolated and without artificial disturbed state of the grassland. The vegetation and the seed bank of the patches showed a low degree of similarity in the same period, while the composition of the spring aspect reflected clearly in the seed bank of late summer in all four patches. Results showed that mosaic-like appearance is not only characteristic of the vegetation, but also the seed bank of the soil. Differentiation of the seed bank manifested mostly after the period of seed-fall, at the end of summer, while in early spring it was less expressed. On the basis of the differentiation of the seed bank we can conclude that not the dispersion of seeds, but natural vicinity of mother plants was decisive in forming the spatial variation of the seed bank.
Cataract surgery is the most frequently performed ophthalmic surgery worldwide. This year approximately 32 million surgeries will be performed. The journey to modern, quick, and safe cataract surgery has been quite long. This review covers topics from ancient couching to the most modern phacoemulsification and femtosecond laser-assisted cataract surgery. The gain in quality of life is the largest with cataract surgery compared to other implant surgeries (e.g. knee, hip replacement, etc.). Ophthalmology has made huge advancements in recent decades. New microsurgical tools and diagnostic equipment have been developed, together with new surgical methods and foldable intraocular lenses, made from biocompatible material. From monofocal lenses, through aspheric, toric, and multifocal lenses, to multifocal toric lenses, today almost all kinds of refractive error can be compensated, including presbyopia. Teamwork, precise preoperative assessment, and fine surgical technique should also be emphasized in order to achieve the best and most predictable postoperative results for both patient and surgeon.
Preeclampsia is a severe, sometimes life-threatening complication of pathological pregnancies. The incidence of neonatal morbidity and mortality is usually increased. Besides general maternal symptoms like hemolysis, low platelet number, elevated liver enzyme level, proteinuria, cardiovascular problems, neurological and cerebral complications, serious ophthalmic symptoms might occur. These include focal or generalized narrowing of the arterioles, flame-shaped retinal haemorrhages, and cotton-wool spots. Rarely, disc swelling, exudative retinal detachment, cystoid macular edema, bilateral occipital lobe infarction, or cortical blindness might occur. In this article, I review the retinal and macular changes, retinal detachment, and the cause of blindness. Optical coherence tomography (OCT) allows ophthalmologists to diagnose early and late changes in choroid vasculature and circulation, and consequent retinal morphological changes. Spectral-domain OCT and enhanced depth imaging provide important insight and possible prognosis for the course of the disease. After termination of the pathological pregnancy, vision returns to normal in most cases; unfortunately, there are some exceptions.
Radioisotope induced X-ray fluorescence analysis is a rather simple and convenient method for investigating ashed plant material.
In order to reduce matrix effects, thin samples (2 mg/cm2) are analyzed to obtain a reasonable compromise between maximum sensitivity and the lowest possible absorption effects. Concentrations
are determined by standard addition method. A precision of 6–8% can be achieved. As an application, analytical results are
given for whole grains of several sorts of wheat.
Although angiogenesis is considered to be indispensable for continuous tumour growth, only very few studies have been published performing microvessel quantification during tumour progression. We mea- sured the tumour vascularity in different stages of rat pancreatic carcinogenesis induced by azaserine and promoted by raw soya flour-containing pancreatotrophic diet. Besides the tumour samples taken at 6 (atypical acinar cell nodules), 15 (adenomas) and 20 (localised adenocarcinomas) months after carcino- gen initiation, we also investigated 3 control groups: tumour-bearing host tissue of azaserine-treated rats and normal tissue of untreated rats kept on standard or pancreatotrophic diet. In contrast with the usual microvessel counting on hot spots, we determined microvascular surface density (SV) and volume den- sity (VV) by electron microscopic morphometry. There was no significant difference in these respect between the control groups. At month 6 after the azaserine induction SV and VV showed slight, non- significant decrease as compared to the host control. Both values remained unchanged until the 15th month and increased significantly by the 20th month. These results may indicate comparable growth rate of tumour and new microvessels in the premalignant stages of carcinogenesis while a more intense angio- genesis than tumour growth afterwards.
In vitro shoot multiplication of Telekia speciosa (Schreb.) Baumg. was tested on media containing benzyladenine, benzyladenine riboside, kinetin, zeatin, meta-topolin or 2-isopentenyladenine in different concentrations. We observed the proliferation rate, the length of shoots, rate of callus formation, and the presence of the hyperhydricity. The highest proliferation rate (13.17) was obtained on medium supplemented with 5.0 μM benzyladenine, however, the leaves were hyperhydrated at this concentration of benzyladenine, therefore for shoot multiplication lower (1.0 μM BA) concentration of benzyladenine is suggested. The longest shoots were achieved using 1.0 μM 2-iP. At this treatment 100% rooting was found, therefore the stage of rooting is omissible using 1.0 μM 2-iP during the multiplication. This in vitro propagation protocol should be useful for conservation as well as mass propagation of this plant species.
The carbon balance of the sandy pasture (Bugac) and the mountain meadow (Mátra) varied between −171 and 96 gC m−2 year−1, and −194 and 14 gC m−2 year−1, respectively, during the study period (2003–2009). Large part of interannual variability of net ecosystem exchange (NEE) was explained by the variation of the annual sum of precipitation in the sandy grassland ecosystem, while this relationship was weaker in the case of the mountain meadow on heavy clay soil. These different responses are largely explained by soil texture characteristics leading to differences in soil water contents available to plants at the two grasslands. The grassland on heavy clay soil was more sensitive to temporal distribution of rainfall for the same reason. The mountain meadow therefore seems to be more vulnerable to droughts, while the sandy grassland is better adapted to water shortage. The precipitation threshold (annual sum), below which the grassland turns into source of carbon dioxide on annual basis, is only 50–80 mm higher than the 10 years average precipitation sum. In extremely dry years (2003, 2007 and 2009), even the sandy grassland ecosystem was not stable enough to maintain its sink character.