Biologia, Bratislava 56 (1), 2001
Ondřej, M., Transgenosis of Arabidopsis thaliana for understanding plant gene structure and functions. Biologia, Bratislava, 56: 1-5, 2001; ISSN 0006 3088.
Insertion mutagenesis of Arabidopsis thaliana is reviewed as efficient means to clone genes known only by phenotype and to correlate gene sequence and function. Random insertions of T-DNA or modified maize transposons introduced into A. thaliana genome by Agrobacterium tumefaciens lead to mutations. The mutation sites are tagged by the T-DNA or modified transposon sequences and they can be cloned by plasmid rescue or iPCR. In order to have 95% probability of hitting all A. thaliana genes, 100 000 independent insertion lines should be induced and this number has already been nearly reached. Only minority of insertion mutations are connected with distinct phenotypic effect, but all insertion mutations in the chosen gene sequence can be selected by pooling insertion lines and utilization of combination of direct and reverse genetic attitudes.
Key words: Agrobacterium tumefaciens, Arabidopsis thaliana, insertion mutagenesis, T-DNA.
Barnabás, B., Pónya, Zs., Szakács, E., Timár, I., Obert B. & Preťová, A. Biotechnology and micromanipulation of sexual processes in flowering plants. Biologia, Bratislava, 56: 7-12, 2001; ISSN 0006-3088.
Sexual reproduction is an essential process in the propagation of flowering plants. The vegetative life cycle of plants starts with the fusion of male and female gametes in the course of double fertilisation. Investigations on the reproductive processes of agriculturally important crop plants, including cereals, are of great importance in breeding and seed sciences. For a long time much of our basic knowledge of sexual reproduction of the flowering plants has been derived from comprehensive information obtained from morphological (histological, cytological and ultrastructural) studies. Recent advances in plant cell and molecular biology have brought new, sophisticated experimental techniques to investigate and to micromanipulate the reproductive cells of plants for various biotechnological purposes (e.g. haploid induction, in vitro fertilisation, DNA transformation).
The present paper gives a review of the results achieved in our cooperating laboratories within the fields of experimental flowering biology and biotechnology of sexual reproduction in cereals.
Key words: androgenesis in vitro, cereals, egg cell, microinjection, pollen cryopreservation.
Hrivnák, R., Oťaheľová, K. & Husák, Š., Nitella mucronata and N. translucens – contribution to occurrence and ecology in Slovakia. Bratislava, Biologia, 56: 13-15, 2001; ISSN 0006-3088.
In 1999 we found two new species of macroscopic algea in the territory of Slovakia – Nitella mucronataI (A. Braun) Miquel 1840 and N. translucens (Person) Agardh 1807. Brief morphological descriptions, ecological and chorological characteristics are included. The plant community of Nitelletum mucronatae is the first record in Slovakia. The name of Nitelletum mucronatae was valid within the meaning of the Code of the phytosociological nemenclatures.
Key words: algae, Nitella mucronata, N. translucens, syntaxonomy, Nitelletum mucronatae, new combination, Slovakia.
A study on the fluctuations of chlorophyll-a concentrations was carried out in Lake Mikri Prespa during the period May 1990 – September 1992. The range of chlorophyll-a concentrations (5.0 to
53.8 μg L-1) as well as the estimated mean value (20.6 μg L-1) lie within the limits characterizing eutrophic lakes. Relative chlorophyll-a content of phytoplankton biomass varied between 0.11 and 1.16% and is considered to lie among the common values given in the literature for temperate lakes. Chlorophyll-a concentrations correlated positively with total phytoplankton biomass whereas chlorophyll-a content per unit biomass correlated negatively with it. Nanoplankton cells seemed to contain more chlorophyll-a than cells of net plankton. The chlorophyll-a content per unit phytoplankton biomass in Lake Mikri Prespa, seemed to be affected mainly by light intensity and phytoplankton cell sizes.Key words: chlorophyll-a, shallow lakes, Mikri Prespa, Greece.
The localities of 15 lichens new or noteworthy to Slovakia are presented. Five taxa are new to the country. These are Lepraria borealis Lohtander & Tønsb., L. eburnea Laundon, L. umbricola Tønsb., Leproloma diffusum Laundon and Placynthiella dasaea (Stirton) Tønsb.
Key words: distribution, lichens, Slovakia.
Pilous, Z. & Šoltés, R., Oreowesia torquescens, a new species to the bryophyte flora of Carpathians (The High Tatra Mountains, Slovakia), Biologia, Bratislava, 56: 29-31, 2001; ISSN 006-3088.
The species Oreoweisia torquescens (Brid.) Wijk et Margadant was originally placed in the genus Weisia but it is placed in Oreoweisia at present. The main distribution is centred in the Alps with rare occurrences in the Schwarzwald Mts. in Germany, and also in Norway. Recently the species has been found in the Tatra Mts., Slovakia. The species may be confused with Dichodontium flavescens Turn., var. seriata Schimp., which also has serrate leaf margins.
Key words: bryophytes, Oreoweisia torquescens, the High Tatra Mts, Slovakia.
The contribution presents the results of bryofloristic research of selected areas during 1993 – 1994 and 1996 – 1997, with summarised bibliographic data since 1970. The field work was focused mainly on threatened, decreasing habitats (e. g. fens, spring communities, old trees, fallows, extensive cultivated fields) and on protected small-scale areas. The following bryophytes are considered rare and threatened in Biele Karpaty Mts: Anthoceros agrestis, Fossombronia wondraczekii, Reboulia hemisphaerica, Entosthodon fascicularis, Ephemerum serratum, Fissidens exilis, Funaria muehlenbergii, Leucobryum glaucum, Myurella julacea, Timmia bavarica, Tomenthypnum nitens, Weissia longifolia, etc.
Key words: bryophytes, Biele Karpaty, Protected Landscape Areas, Slovakia.
The submitted checklist of microscopic fungi of Slovakia (Zygomycota - Mucorales, Zoopagales, Kickxellales) is a supplement to the Checklist of non - vascular and vascular plants of Slovakia (Marhold & Hindák, 1998). We submit names of species, some known synonyms and bibliography.
Key words: microscopic fungi, Zygomycota, Mucorales, Zoopagales, Kickxellales.
Bíziková, L., Chromosome numbers of the genus Xanthoxalis (Oxalidaceae). Biologia, Bratislava, 56: 53-56, 2001; ISSN 0006-3088.
In Slovakia, the genus Xanthoxalis Small is represented by three species Xanthoxalis corniculata (L.) Small, Xanthoxalis fontana (Bunge) Holub, and Xanthoxalis dillenii (Jacq.) Holub. All chromosome numbers reported in this paper were counted on somatic mitoses in the root tips.Our count for X. fontana (2n=24) and for X. dillenii (2n=24) agree with previous analysis from the same phytogeographical district. For X. corniculata the numbers 2n=48 and 2n=28 were observed. The count (2n=48) has previously been reported from Slovakia, and the chromosome number (2n=28) is the first report from Europe. Summary of all published chromosome numbers is added.
Key words: Xanthoxalis, chromosome numbers, Slovakia.
The small-scale spatial patterns in Allium oleraceum L. and A. vineale L. populations, both common European geophytes, were studied in four contrasting habitats (meadow, scree, scrub, and forest). Coefficient of dispersion indicated marked clumped distribution of the individuals of both species in all habitats. Pattern analysis revealed considerable differences in pattern of both species studied and among populations of respective species studied. The analyses clearly point at two distinct morphological features of both species concerning dispersion, which affect pattern of their populations – formation of daughter bulbs and that of aerial bulbils. Existence of ”morphological” patches of A. oleraceum, corresponding to clumps of plants originated from daughter bulbs, were detected since daughter bulbs were frequently produced above ground and thus embodied a potential to disperse to the longer distance from the parent plants. Cluster dispersion of bulbils and their restricted dispersal distances were responsible for occurrence of small patches and second-order patches in most population of both species.
Key words: Allium oleraceum L. and A. vineale L., clumping, density, dispersion, pattern, two term local variance method (TTLQV).
In the course of the twentieth century, multiple changes in the water regime occurred in the region of the Dyje-Morava floodplain (Czech Republic, south of Brno). Response of the herb layer to these changes were documented in nine permanent experimental geobiocoenological plots representing the three most common groups of geobiocoene types of floodplain communities stiuated in the Cahanov – Soutok National Neture Reserve. Using the TYP computer program, time series of phytosociological relevés from 1973, 1994 and 1998 were evaluated in relation to water regime conditions. In natural communities, the proportion of hydrophilic plant species was gradually decreasing in the absence of floods and with the sinking groundwater table. After artificial flooding, however, the representation of the hydrochorous and hydrophilic plants rapidly and substantially increased in these plots.
Key words: floodplain forest, herb layer, phytoindication, water regime, artificial flooding.
The Korean subalpine coniferous forests were analyzed with respect to the phytogeographical distribution types according of their species composition. In the forests, the Manchurian (Northeast China) element showed obviously a declining trend with increasing latitude, while the Japanese element was the reverse. Thus the Taxo-Pinetum pumilae and Thujo-Abietetum neprolepis distribution in northern part of South Korea were characterised by more frequent occurrence of the Manchurian element, compared to the Abieti-Piceetum jesoensis, Saso-Abietetum koreanae and Betulo saitoanae-Abietetum koreanae occurring southwards. In contrast the latter, three associations were much richer in the Japanese element than two associations occurring northwards. On the other hand the Korean endemics showed a rising trend with increasing altitude, especially in the same geographical regions.
Key words: distribution, floral comparison, subalpine coniferous forest, South Korea.
The effects of reinstatement operation of meander (connection with the river) on dynamics of riparian vegetation have been analysed. Soil properties and vegetation pattern were repeatedly analysed at permanent plot before and after the reinstatement. The changes of abiotic conditions e.g. microrelief, increasing of clay particles in upper soil horizon resulted in transformation of vegetation. Many of stenoecious species were substituted by euryoecious ones and horizontal structure of vegetation has been markedly simplified.
Key words: vegetation dynamics, riparian vegetation, permanent plot, Morava river
In the very wide spectrum of the Malé Karpaty Mts plant communities of the termophilous oak forests, the alliance Quercion pubescenti-petreae Br.-Bl. 1931 has a specific position. They belong to communities with high phytodiversity not only in the Male Karpaty Mts, but within whole Slovakia. The value of conservated stands is very high from the standpoint of protection, because the original stands are mostly defrosted or refrosted by allochtonous woody plants. In this contribution results of the phytocoenological research, realised in the years 1997 and 1998 are presented. For selection of syntaxons the Zurrich-Montpellier School methods were applied, inner variability of the syntaxons was evaluated by ordination methods. There were 73 relevés made, 63 relevés were classified after analysis into the following three syntaxons of the alliancie Quercion pubescenti-petreae, Pruno mahaleb- Quercion pubescentis, Corno-Quercetum, Corno-Quercetum variant with Melica uniflora.
Key words: Quercion pubescenti-petreae, phytocoenology, Malé Karpaty Mts, Slovakia.
Percentage of germination was ascertained in seed materials of Rumex obtusifolius and R. crispus collected at localities of five geographic regions of south-western and central Europe (Spain, France, Slovakia, Czech Republic, Germany) between 42º and 53º N. Seeds were sampled before dispersal from dry shoots (in autumn and winter) separately from 3 to 5 randomly selected plants at each locality. Germinability was tested 40-60 d after harvest at constant 25 ºC and light. The incidence of innate seed dormancy was generally high. Average proportion of germinable seeds was below ten percent at 64% of localities of R. crispus and 49% of localities of R. obtusifolius. In bothe species, there was a significant variation of germinability between localities within geographic regions but differences between regions were small. Significant geographic differences were found in R. crispus where there was a trend for increasing germination percentage as one moves from southern to northern regions and from low to high altitudes (established at localities of Spain). The trends may indicate a selaction for late flowering ecotypes with a decreased incidence of innate seed dormancy. No significant geographic or altitudinal trends in germination were established in R. obtusifolius.
Key words: Rumex obtusifolius, R. crispus, broadleaved dock, curled dock, seed dormancy, germinability, geographic variation.
The aim of the experiment was to investigate the effect of lead ions on the process of chloroplast development in etiolated Lemna minor. Absorbance measurement showed that after 24 h of exposure to light the level of chlorophyll a in the material exposed to the stress factor was half as high as in the control material. After 7 days the chlorophyll a content of Pb-treated plants was higher than that of the control plants. Lead caused also a decrease in the level of chlorophyll b, but the difference between control and the Pb-treated plants did not decline in time. The concentration of carotenoids under the influence of Pb2+ was lower, but latter it exceeded the level recorded in the control material. In the control plants the photosynthetic apparatus developed very quickly on exposure to light. After 48 h the plastids had small grana and after 7 days the plastids were typical mature chloroplasts. In plants treated with Pb2+ before exposure to light, the process of chloroplast development was delayed. After 7 days chloroplasts were present in this material, but they were different from those found in control and unetiolated material because of the presence of vesicles near the envelope.
Key words: Lemna minor, etiolated plants, chloroplastogenesis, lead, in vitro.
Spatial genetic structure and mating system in wild cherry (Prunus avium [L.] Moench.) population in Central Slovakia was investigated employing isozyme genetic markers. Quite low levels of the genetic diversity were found (1.6 alleles per locus, mean expected heterozygosity of 0.146). Mating system analysis revealed a quite highly effective selfing rate (5.1%), indicating a high rate of mating among relatives, with an extreme variation of effective selfing rates among individual maternal trees (0–82%).
Key words: Prunus avium, mating system, spatial autocorrelation.
Seedlings of Azadirachta indica were inoculated with VAM fungus Glomus fasciculatum and/or phosphatase producing fungus Aspergillus fumigatus in a pot experiment. Dual inoculation increased dry biomass of shoot and root, root length, concentrations of P and, to a lesser extent of K and Mg. Shoot concentration of Cu and Zn were only enhanced by G. fasciculatum not by A. fumigatus. At harvest, depletion of P in the rhizosphere soil increased in the order of sterilized soil< A. fumigatus < G. fasciculatum < A. fumigatus + G. fasciculatum which corresponds with the enhanced ion concentration in the plants.
Key words: Glomus fasciculatum, Aspergillus fumigatus, Azadirachta indica, seedlings, inoculation.