The effect of visible light on mutagenic activity of 1-methyl-1-nitrosourea and 1-methyl-3-nitro-1-nitrosoguanidine

J. Velemínský, V. Pokorný, T. Gichner

Biologia plantarum 10:85, 1968 | DOI: 10.1007/BF02921022

Irradiation with visible light reduced the mutagenic activity of 1-methyl-1-nitrosourea (MNH) and 1-methyl-3-nitro-1-nitrosoguanidine (MNG) solutions during their application onArabidopsis thaliana seeds for 24 hours. The antimutagenic effect of light was stronger with MNG than with MNH and in solutions buffered to pH 5 than in aqueous solutions. The decrease of activity of both the mutagens corresponded with the rate and degree of their photolysis. In the paper are presented the curves for the dependence of the decomposition of both substances and the formation of nitrous acid on pH and temperature of the solutions, amount of seeds.

Cultivation of the cryosestonic alga Koliella tatrae (Kol) Hind.

F. Hindák, J. Komárek

Biologia plantarum 10:95, 1968 | DOI: 10.1007/BF02921023

The cryosestonic unicellular green algaKoliella tatrae (Kol) Hind., which grows in the surface layers of the summer snow-fields of the Vel'ký Žl'ab valley in the Belánske Tatry Mountains (Czechoslovakia), was started to be cultured at the laboratory. This alga may be considered as a typical (true) cryobiont, the optimal growth of which requires about 4°C; long-lasting temperatures ranging from more than 10°C have a lethal effect. The low-temperature strain obtained is suitable for the comparison with unicellular green algae, used as models for the study of the photosynthetic activity and metabolic processes of autotrophic micro-organisms (Chlorella,...

Effect of root tip amputation on spiral oscillations of the growing hypocotyl with radicle of the pea (Pisum sativum L.)

M. Spurný

Biologia plantarum 10:98, 1968 | DOI: 10.1007/BF02921024

In order to interpret the mechanism of elongation growth of the hypocotyl with radicle in the first stages of germination of the pea seed (Pisum sativum L.) a cybernetic model utilizing feed-back as a mechanism of correcting the wrong direction of growth was proposed (Spurný 1966, 1967). In the present study, the effect of amputation of the root tip as the control centre on the trajectory of the growing radicle was investigated. The results have shown that the hypocotyl grows, elongates-the rate of growth being slightly lower than that of the standard, but that no spiral oscillations at all are executed by the organ after amputation of the root...

Endopolyploidy in the roots of rye,Secale cereale L.

J. Dvořák

Biologia plantarum 10:112-117, 1968 | DOI: 10.1007/BF02921025

2,4-D was applied to the roots of diploid and tetraploid corn. After the application the mitotic division in the meristem of root tips was blocked; the mitotic division in differentiated cells of cortex and central cylinder, on the other hand, was provoked. In the cortex of diploid corn (variety České) predominantly tetraploid were found cells with 28 chromosomes and, to a lesser extent, octoploid and diploid ones with 56 and 14 chromosomes respectively. In the cortex of tetraploid corn (variety Bernburger Tetraroggen), most cells were octoploid with 56 chromosomes; the metaphase levels with 112 and 28 chromosomes, e.g. 16-ploid and tetraploid cells,...

Quantitative analysis of free amino acids and carbohydrates in spring barley anthers at different stages of maturity

Zdeňka Nátrová

Biologia plantarum 10:118, 1968 | DOI: 10.1007/BF02921026

The content of the carbohydrates glucose, fructose and sucrose was determined in spring barley anthers at different stages of maturity. During maturation the sucrose content of the anthers increased markedly. The following 17 free amino acids were detected in anthers of different stages of maturity: aspartic acid, glutamic acid, serine, alanine, arginine, leucine, isoleucine, lysine, α-aminobutyric acid, glutamine, proline, tyrosine, phenylalanine, valine, threonine, cystine and glycine. Quantitative analysis was only carried out in amino acids present in higher concentrations in the analysed samples. These were: aspartic acid, glutamic acid,...

Chlorophyll mutations after low doses of chronic irradiation of barley

R. Hončariv, V. Danko, L. Kováč

Biologia plantarum 10:127-130, 1968 | DOI: 10.1007/BF02921027

The chlorophyll mutation rate on a large number of plants after the dose rates 0.004-16.800 R/day during the whole vegetation cycle was examined. The mutation frequency increases as early as after the dose rate 4 mR/day. The dose rate of approximately 8 mR/day is necessary to double the mutation frequency.

Development of the shoot apex ofChenopodium rubrum L. after photoperiodic induction in the cotyledon stage

Frideta Seidlová, Jindra Štichová

Biologia plantarum 10:131, 1968 | DOI: 10.1007/BF02921028

Development of the shoot apex up to floral differentiation was investigated in the short-day plantChenopodium rubrum. The changes occurring in the apex from energence until full opening of the cotyledons (Figs 1-4), development during photoperiodic induction (Figs. 5-8), as well as the resulting floral differentiation (Figs. 9-10) are described. It was aimed at excluding the influence of plastochron changes on the interpretation of ontogeny of the shoot apex. For that reason two planes of longitudinal sections and two plastochron stages were compared.
In young plants zonation does not become fully evident prior to floral differentiation....

Humus acids as a nutrition source for some white-rot fungi

Marta Tesařová, L. Scháněl

Biologia plantarum 10:135, 1968 | DOI: 10.1007/BF02921029

The rate of growth of 5 species of white-rot fungi on an agar medium with additions of humus acids was used for assessing the ability of these fungi to utilize humus acids as a sole source of nutrition. Differences in the effect of the various fractions of humus acids and their concentrations, as well as in the reaction of the fungi tested were observed. During the growth, loss of colour of agar media with humus acids was observed. Activity of lacease in the discoloured areas was highest.

Electron microscopical proof of the presence of sugar beet yellows virus particles in the roots of sugar beet

J. Chod, J. Polák, O. Klír

Biologia plantarum 10:142-145, 1968 | DOI: 10.1007/BF02921030

The presence of beet yellows virus (BYV) particles was electron microscopically proved in the roots of sugar beet. Specimens for the electron microscopical examination of root sap were prepared by differential centrifugation. It was proved that, contrary to expectations, examinations in spring showed most virus particles in the basal part of the root. At the same time it was found by experiment that the diagnostical BYV antiserum, for which the antigen was prepared from sugar beet leaves, did not react with a purificate of BYV containing virus particles.

Phenotypic, genotypic and environmental correlations of quantitative characters in winter wheat

J. Smoček

Biologia plantarum 10:146-155, 1968 | DOI: 10.1007/BF02921031

In the experiment with 18 winter varieties the genotypic, phenotypic and environmental correlations were estimated in all combinations between the pairs of 11 quantitative characters.
Both yield of grain with its components and further characters were evaluated, of which flag leaf size and leaf angle of the last but one leaf are of importance for the utilization of light energy and consequently for receiving maximum rates of photosynthesis.
In simple genotypic and phenotypic correlations their different stability with regard to mineral nutrition, eventually to the date of sowing was proved.
In the discussion the limited signification of simple...

XI International Botanical Progress

Biologia plantarum 10:155, 1968 | DOI: 10.1007/BF02921032