Nomenclatural remarks on the association names ofNardus stricta-rich communities in Central Europe

The present paper gives comments on the nomenclature of associations ofNardetalia andNardo-Caricion rigidae from Central Europe. A brief list of important homonyms and ambiguous names is added.     

Heterochromatin distribution and chiasma localization in the grasshopper Bryodema tuberculata (fabr.) (Acrididae)

The problem of extreme localisation of chiasmata in the grasshopper species Bryodema tuberculata has been reinvestigated, using C-banding, Q-banding and benzimidazol techniques. These techniques reveal the precise localisation of heterochromatin in different chromosomes. Single or double heterochromatic blocks are present near the centromeric regions, except in chromosomes 5 and 11, which have larger blocks. These two chromosomes possess a distal chiasma while the other autosomes have a proximal chiasma. The results with regard to the distribution of chiasmata, in relation to the localisation of heterochromatin, as well as the existence of a short arm, are compared with the earlier observations of White, and discussed briefly.     

Intracytoplasmatic inclusions in cells of lettuce leaves with mosaic-like symptoms

Ultrathin sections were prepared from the tissues of lettuce leaves with mosaic-like symptoms and thickened nervature which were studied by means of electron microscopy. Intracellular inclusions surrounded by a membrane were found in the cytoplasm of parenchym cells of the investigated lettuce leaves(Lactuca saliva L. provar.capitata L. nid.jaggeri Helm., cv. Pra?an). Crystals with a distinctly apparent hexagonal lattice could be observed in the inclusions. No crystal containing inclusions were found in the tissues from the leaves without mosaic-like symptoms and in those from thickened nervature.     

Some properties of pea enation mosaic virus isolated from field pea and broad bean plants in Bohemia

Pea enation mosaic virus (PEMV) was isolated from disea sed field pea (Pisum sativum L.ssp. arvense A.Gr.) and broad bean (Faba vulgaris Moench) plants grown as filed crops at Bohumilice in Bohemia. The virus proved to be pathogenic for the following plant species:Pisum sativum L. cv. Raman,Faba vulgaris Moench,Lens culinaris Med.,Vicia sativa L.,Lathyrus odoratus L.,Glycine soja L.,Phaseolus vulgaris L.,Chenopodium amaranticolor Coste andReyn,Nicotiana clevelandi Gray,Trifolium incarnatum L. The dilution end point of the isolate was higher in pea plants (10^?4) than in broad bean plants (10^?2). The thermal inactivation point was 65–68° and the longevityin vitro between 10 and 14 days. According to the host range, symptoms on pea plants and physical properties the virus isolate studied resembles some isolates described in the U.S.A. and represents a PEMV strain different from those reported so far in Czechoslovakia.     

Secondary responsein vitro to antigen ΦX 174 phage

In a model secondary reactionin vitro, a correlation was demonstrated between the size of the antigen dose used for the prestimulation of spleen tissue donors and the type of antibodies formed in the anamnestic reaction. After a small dose of antigen ΦX 174, the antibody response three days after prestimulation was of the 19 S (IgM) type, but later secondary contactin vitro (after four months) did not produce a 19 S anamnestic reaction. After large primary doses of antigen, a short interval between primary and secondary contact led to the formation of 19 and 7 S type antibodies, while after a long interval only 7 S (IgG) type antibodies were formed. The results are discussed in relation to differences in the size of the antigen dose needed to induce short-term 19 S and long-term 7 S immunological memory.     

A Comparative study on the reactions for protein sulphydryl,carboxyl and tyrosine in plant nuclei

V této práci byly aplikovány na rostlinných objektech reakce s β-oxynaftyl-merkurichloridem a p-nitrobromacetofenonem, popsané k pr?kazu bílkovinných SH na materiálu ?ivo?i?ném. V rostlinných meristematických buňkách obě tyto techniky stejně jako DDD¹ a RSR¹ jeví vět?inou intensivněj?í zbarvení jader ne? cytoplasmy. Rovně? po aplikaci reakcí na bílkovinné karboxyly a tyrosin je jádro intensivněji zbarveno ne? cytoplasma. Z toho lze soudit, ?e rozdíly v intensitě zbarvení jádra a cytoplasmy v meristematických buňkách rostlinných technikami k pr?kazu bílkovinných SH jsou zp?sobeny spí? rozdílem v celkové koncentraci bílkovin ne? zv??ením podílu cysteinu v jaderných bílkovinách.     

Variance deficit is not reliable evidence for niche limitation

Variance deficit in the number of species per sampling unit, as compared to a null model with species occurring independently of each other has been considered by various authors to be evidence for niche limitation. I show that simpler mechanisms could explain this phenomenon. Of those, the competition of individuals for space limits the number of individuals per sampling unit, resulting in decrease of variance in species richness. Testing the proportions of species belonging to various guilds seems to be more ecologically interesting, although here also the variance deficit can hardly be taken as reliable evidence for niche limitation.     

Application of the exploratory data analysis for evaluating the toxicity of chlorinated phenol derivatives by various cell models

Exploratory data analysis based on multivariate statistical analysis techniques was introduced as a new approach to expressing the toxicity of chemical substances at the simultaneous acceptance of various cell models. Using principal component analysis and cluster analysis methods the toxicity of chlorinated phenol derivatives on employing some of the cell models (chlorococcal algae, cyanobacteria, bacteria, micromycetes, plant and animal cells) was characterized. The previous empirical experience that the toxicity of chlorinated phenol derivatives will increase with a growing degree of chlorination and that the presence of the methoxy group will cause a lowering of the toxic effect was demonstrated. The relationship between groups of tests used was presented.