Biologia, Bratislava 55 (1), 2000
The procaryotic nostocalean genus Richelia Johs. Schmidt 1901 (Cyanophyta/Cyanpbacteria) is characteristic by short trichomes with terminal heterocytes and by the absence of akinetes. The only described species, R. intracelularisI Johs. Schmidt 1901, occurs in warm oceans symbiotically in the frustules of diatoms Rhizosolenia or Hemiaulus, or epiphytically on Chaetoceros, In this article the second species of the genus, originally described from rice flieds in SE Asia as Anabaena siamensis, is transferred into the genus Richelia. The species is also characterized by short trichomes and spherical to oval or conical terminal heterocystes, and the absence of akinetes. Pro-heterocytes in R.siamensis are formed intercalary from one vegetative cell which divides into two daughter cells. The parental trichomes is broken into two daughter trichomes just at the connection of pro-heterocytes. Pro-heterocytes at the ends of trichomes are fully developed into heterocytes later. It is this character that separates R. siamensis from the representatives of the genus Anabaenoposis (Woloszynska) Miller, in which pro-heterocytes are formed from two neghbouring cells and ripen directly in the parental trichomes. Specimens similar to Anabaena sinensis have been observed in littoral of lakes, small channels and pools in Slovakia. The position of the genus Richelia in the Nostocaceae family is discussed.
Key words: Cyanophyta/Cyanobacteria, Richelia siamensis, new combinantion, pools, dead arms, SE Asia, Israel, Slovakia.
The checklist contains all records of cyanophytes(cyanobacteria and algae from the Slovak stretch of the Danube river validly published during the years of 1926-1999. Alltogether 282 genera with 1050 species and infraspecific taxa have been found in the Slovak part of the Danube. This enumeration proceeds the first checklist of the Slovak Danube cyanophytes and algae (Hindák & Záhumenský, 1983) in which 590 infrageneric taxa belonging to 191 genera were registered. During the period of 1981-1994 most taxa were confirmed again (123 genera with 273 infraspecific taxa), but 27 genera with 145 species, 17 varieties and 2 formas were recorded for the first time from this part of Danube (Hindák, 1995).
Key words: checklist, cyanophytes and algae, Danube river, Slovakia.
A survey of summer phytoplankton assemblages of 15 ponds at Varanasi (India) revealed the significance of pH and the nutrient ratios for the structure of the assemblage. Definite relationships between various nutrient ratios and distribution of phytoplankton groups emerged out of this study. The cyanophytes mainly dominated ponds with a high pH and an inorganic N:P ratio less than 11:1 suggesting their being superior N competitors, whereas low pH and high N:P ratio generally favoured the chlorophytes and diatoms. Euglenophyte abundance was associated with high levels of ammonia and organic matter. Despite the high Si:P ratio in the study ponds, diatoms seldom assumed dominance except for some macrophyte-covered ponds due probably to nitrogen limitation. The macrophyte-covered ponds had low algal biomass and were dominated by green algae and diatoms. Canonical correspondence analysis clearly elucidated the preference of cyanophytes to high pH and low nitrate-nitrogen and chlorpohytes to high phosphate, nitrate and low pH. The broad range of N:P ratio in the study ponds indicates both N and P limitation with different species becoming dominant at different ratios. The most commonly occurring species were Microcystis aeruginosa and Chlorella vulgaris, with the former attaining maximal biomass in a pond with N:P ratio of 9:1. The latter species, however, occurred over a wider range of N:P ratio.
Key words: phytoplankton, community structure, pH, nutrients, Microcystis, Chlorella, biovolume, India.
Epiphytic vegetation of lichens and mosses was investigated on trunks of Abies cephalonica on Mount Aenos, Kefallinia, Ionian Island (Greece). A simple sampling design involving a series of relevés along decreasing altitude revealed clear clinal pattern of floristic variation in the epiphytic flora. Species richness of both mosses and lichens were negatively correlated with the increase of altitude, suggesting that the cold-stressed top of the mountain (and the frequency of fog precipitating on the top) play major role in the epiphytic community structuring even along a short altitude span of 200 m.
Key words: Abies cephalonica, coenocline, cryptogamic vegetation, fog, Ionian Islands, lichens, mosses, ordination, Greece.
Epipactis greuteri H. Baumann et Künkele was discovered on two localities in the Súľovské vrchy Mts as a new species of the Slovak flora. Distribution, diagnostic characters, variability, as well as ecology of this species are analysed in detail. Morphological characters of the species are documented by drawings. Epipactis greuteri occurs in Slovakia also in the Malá Fatra Mts, Pieniny Mts, and Javorníky Mts.
Key words: orchids, Epipactis greuteri, new species, Slovak flora.
An integrated system for the ecological evaluation of vegetation maps based on syntaxa, is proposed for nature conservation purposes in Greece. On the basis of the phytosociological information, several criteria such as naturalness, threat, rarity, floristic-phytocoenotic value, replaceability, are applied and the result is expressed in the form of an index. A detailed scoring system, on the basis of scale ranging from 0 to 10 for the assessment of each of the ecological criteria, in correspondence with the syntaxa of Greece at the class level is given. A simple formula to evaluate the Total Conservation Interest of the mapped vegetation units or complexes is proposed in order to establish protection priorities.
Key words: applied phytosociology, communitty diversity, landscape managment, species diversity, syntaxonomy, vegetation monitoring, Greece.
Phases of primary succession and resulting plant communities on quartzite outcrop were studied in six mountain ranges in the state of Minas Gerais, Brazil. The complex of lithopytic Pleurothallis (Orchidaceae), consist of terete-leaved species which characteristically grow on quartzite outcrops in the campos rupestres of Minas Gerais and Bahia, Brazil. In that vegetation they are frequntly the first vascular plants to colonize quartzite outcrops not necessarily overgrown by lichens or mosses. Lone speciments of the other vascular plspecies were rarely observed and recorded on the barren cliffs. New association Encyclio vespae-Pleurothallidetum teres and Encyclio vespae-Pleurothallidetum johannensis with two subassociations (pleurothallidetosum and oncidietosum blanchetii) were described.
Key words: campo rupestre, primary succession, saxicolous vegetation, Brazil.
Beet mosaic virus (BtMV) isolate REN-1, originating from field infected sugar beet in western Slovakia was characterised. Virus caused systemic infection on 7 of 8 plant species tested by mechanical inoculation. Pisum sativum cv. Junák and Nicotiana clevelandii x glutinosa were found to be suitable hosts for purification. Purified virus preparation contained filamentous flexuous particles typical for the Polyvirus genus when observed under electrone microsope. In SDS_PAGE the viral capsid proteins (CP) migrated as one major band with a molecular mass of about 30 kDa. BtMV CPs were detected in western blot analysis both from purified virus preparations as well as crude plant sap. BtMV REN-1 was recognised in western blots also by three heterologous anti-potyvirus antisera as well as two monoclonal antibodies against pea seed-born mosaic virus.
Key words: beet mosaic potyvirus, symptomatology, ELISA, western blot, electron microscopy, serological relationship.
In-growth techniques were used to assess yearly root and rhizome increments of two acidophilic grasses on habitats situated along a gradient of increasing pollution and climatic impacts in the Beskydy Mts. The most intensive root growth was recorded on sites situated at lower altitudes, i.e., in the valley of the Černá Ostravice river (in the stand of C. villosa 0.703 g sample-1 year-1) and at the locality Bílý Kříž (C. villosa 0.251 g sample-1 year-1, C. arundinacea 0.296 g sample-1 year-1. The lowest values for root growth rates were usually assessed in stands of both plants species growing on habitats fully exposed to incoming pollution at the higher altitudes. A significant negative correlation was, however, found only between altitude and yearly root increments in old C. villosa stands. Similarly, the highest yearly rhizome increments of C. vilosa, i.e. 50.7 and 17.6 g m-2 year-1, and 87.9 and 38.6 g m-2 year-1, were recorded in old stands growing in clearings at localities Černá Ostravice (630 m a.s.l.) and Bílý Kříž (945 m a.s.l.), respectively. The lowest values were assessed in stands near the top of both the Knihyni and Smrk Mt. (0.5 to 4.8 g m-2 year-1 and 0.97 to 7.59 g m-2 year-1) fully exposed to incoming pollution. Close negative correlation have thus been found between altitude and yearly increments of both rhizome dry mass and rhizome length recorded in old stands on defrosted sites. Results of our studies indicate reduction in yearly root and rhizome increment in stands of both acidophilic grass species growing in conditions of the higher altitude, i.e., in unfavourable conditions of higher pollution (acid deposits) and climatic impacts.
Key words: acidophilic grasses, altitude, air pollution, rhizome length, rhizome dry mass, yearly root increment.
The ability of adventitious shoot induction from hypocotyl, stem, peduncle and leaf explants of Jatropha integerrima on MS medium containing 0.1 to 2.0 mg L-1 of BA, kinetin or zeatin in combination with 1.0 mg L-1 IBA were compared. From cytokinins tested, BA was the most effective in promoting shoot induction on various explants. Shoot regeneration frequency varied between 19.6 and 100% in dependence on the explant. The highest shoot regeneration potential was observed on stem and leaf segments. However, leaf segments failed to regenerate shoots on the medium supplemented with kinetin and zeatin. Differences due to explant, cytokinin type, cytokinin concentration and their and their interactions on the frequency of callus formation and shoot induction were highly significant. Histological sections revealed early stages of embryoids development in leaf and peduncle explants, however, the regeneration from all explants was predominantly through organogenesis.
Key words: adventitious shoot induction, callus induction, cytokinins, explants, Jatropha integerrima, somatic embryogenesis.
Pharmacological agents, disturbing actin cytoskeleton and exocytosis, exert dramatic effects on root hair morphology in Poa annua L. roots. Inhibitors used in the present study induced two major types of root morphology disorders. The first type consisted of various types of hair tip branching induced either by general inhibitor of myosin ATPases, 2,3-butanedione monoxime, or by exocytosis inhibitors monensin and caffein. Siumilar bifurcation of hair tip was induced in some root hairs with microtubule depolymerization drug oryzalin. The second type of morphological anomaly was represented by swellings and bulging of growing root hair tips and was induced by partial disintegration of actin filaments (Afs) via cytochalasin D. On the other hand, complete depolymerization of Afs with latrunculin B immediately stopped the root hair growth although root hair initiation continued. Intriguingly, inhibitor-induced hair phenotypes closely resembled diverse root hair mutants of Arabidopsis thaliana, suggesting that pharmacological agents which affect the actin-based cytoskeleton and exocytotic machinery can phenocopy diverse root hair mutants. This pharmacological approach turns out to be a promising additional avenue in our efforts to determine the identity of highly elusive factors controlling polarity of walled plant cells.
Key words: actin cytoskeleton, exocytosis, inhibitors, Poa annua, root hair morphology, Zea mays.
Hajduch, M., Debre, F., Böhmová, B. & Preťová, A.,
Effect of sodium azide and gama-irradiation on the seed protein composition of soybean. Biologia, Bratislava, 55: 115-120, 2000; ISSN 0006-3088.Soybean seeds Glycine max L. cvs. Toping and Tolena were treated with gama-irradiation and/or 1 mM solution of sodium azide. M3 generation was examined for variability in seed proteins using SDS-PAGE electrophoresis. We found four main mutatuions occurring in M3 plants of Topind and three mutations occurring in M3 generation of Tolena. In M3 plants of both varieties we found increased expression of 51 kDa protein. Of all the analysed M3 plants of Tolenna, the 54.5% fraction of progeny in missing 28 kDa protein. In total we have found mutations in seed protein composition in 77.0% and 23.12% of analysed M3 plants of Tolena and Toping, respectively. There are no significant differences in expression of 11S and 7S subunits of seed storage proteins.
Key words: chemical mutagenesis, gama-irradiation, M3 plants, proteins, soybean.
The micropropagation of grapevine cvs Vugava and Plavac mali through nodal segment method was studied. For culture establishment green, one-node cuttings from the vineyard plants were used. Musrashige and Skoog (MS) medium supplemented with 4.4 µM BA was the most useful to induce bud growth in both cultivars. After two to four weeks of culture, axillary shoots were excised from nodal segments and transferred to the same basal medium with addition of 11.4 µM IAA for further four weeks. This method was suitable for the culture establishment of both cultivars. Growing shoots were excised to obtain new one-node sterile minicuttings that were again cultured. Nodal method has a potential value in commercial clonal propagation of Vugava cultivar. In the culture of Plavac mali, shoot growth was inconsistent and in vitro propagation was strongly limited.
Key words: grapevine, micropropagation, nodal segments, genotype, growth regulators.