Einige gedanken von Bohumil NĚmec

J. Kloz

Biologia plantarum 15:1-2, 1973 | DOI: 10.1007/BF02922504

Die jugend Bohumil NĚMEC's

Josef Kloz

Biologia plantarum 15:3-8, 1973 | DOI: 10.1007/BF02922505

On the occasion of the 100th anniversary of the birth of academician Bohumil Nźmec

Rudolf Dostál

Biologia plantarum 15:9-11, 1973 | DOI: 10.1007/BF02922506

Fragments of reminiscences on academician Bohumil Němec

Ctibor Blattný

Biologia plantarum 15:12-16, 1973 | DOI: 10.1007/BF02922507

The photographs and drawings of academician Nźmec

Jiří Fiala

Biologia plantarum 15:17-19, 1973 | DOI: 10.1007/BF02922508

Relation between the level of endogenous growth regulators and the differentiation of the fungusLentinus tigrinus studied in a synthetic medium

V. Rypáček, Z. Sladký

Biologia plantarum 15:20-26, 1973 | DOI: 10.1007/BF02922509

The fungusLentinus tigrinus was cultivated in a synthetic medium. During vegetative growth of mycelium and differentiation of fruiting bodies samples serving for determination of endogenous growth regulators were collected. The material was extracted with methanol, separated by chromatography and the isolated fractions were tested. Substances of auxin type were assayed with coleoptile segments of oat plants, gibberellins by measuring the hypocotyl growth in the lettuce and cytokinins from the degree of chlorophyll decomposition in the leaf segments of barley. Very low content of auxins was found in all phases of growth and differentiation of...

Correlative integration in dormant tubers of circaea intermedia

R. DostÁl

Biologia plantarum 15:27-36, 1973 | DOI: 10.1007/BF02922510

The apical dominance in dormant tubers ofCircaea intermedia preventing the extension of lateral buds under favourable conditions differs from the apically directed growth inhibition inducing true dormancy in the tubers. This acropetal inhibition affects the tuber tip more strongly than its lateral buds, which develop into long stolon-like shoots after the tuber decapitation. The local supply of ABA shows no tuberizing effect, but enhances the dormancy of the tuber top. MH interrupts the correlation between the tuber laterals tuberizing without previous stolon formation. The uppermost leaf structures participate in the apical dominance, inhibiting...

The extent and differences in mitotic activity of the root tip ofVicia faba L.

Mária Luxová, A. Murín

Biologia plantarum 15:37-43, 1973 | DOI: 10.1007/BF02922511

Mitotic activity does not stop for different meristematic cells of the root apex at the same distance from the initials. The differences are connected with the functional heterogeneity of the apical meristem of the root. The arrangement of vascular bundles,i.e. the alternation of independent xylem and phloem groups, is of major importance. In broad bean roots, the protophloem sieve elements stop dividing first. The centre of the stelei. e. late metaxylem elements stop dividing next. Division in the stele gradually ceases centrifugally, while it ceases centripetally in the peripheral part of the root. The cylindrical region with prolonged...

Effect of allylisothiocyanate on nuclear division inPisun sativum

Zdenka PazourkovÁ

Biologia plantarum 15:44-49, 1973 | DOI: 10.1007/BF02922512

In the course of the study of the effect of allylisothiocyanate in a 10^-4 dilution on the mitosis ofPisum sativum root tips, some cells with typical meiotic configurations were found. After 92 h of treatment about 2% of the dividing cells were in the state resembling a so called somatic reduction.

On the media improving freeze-sectioning of plant material

K. BeneŠ

Biologia plantarum 15:50-56, 1973 | DOI: 10.1007/BF02922513

Using a semiconductor freezing microtome, there is no difficulty in getting an ample supply of quite suitable sections of Ca formol fixed root tips ofVicia faba, applying Holt's sirup or plain 0.88 M sucrose as media for keeping the material, getting the sections and treating them after sectioning, but the protoplasts shrink and often fall out from the cells. No improvement in this respect was revealed using - at different concentrations - sucrose and arabic gum alone. The changes in the proportions of the ingredients of the sirup were also ineffective. A series of experiments were therefore performed with plain sucrose, but none of the factors...

Changes in the transpiration rate of barley plants infected with powdery mildew in the light and in the dark

S. PriehradnÝ

Biologia plantarum 15:57-64, 1973 | DOI: 10.1007/BF02922514

Changes in the transpiration rate of intact spring barley plants, cv. "Slovensky dunajsky trh", were studied separately in the light and in the dark under controlled temperature and illumination, after the infection withErysiphe graminis DC, during an 8 day period of the development of the fungus. In the first stage of pathogenesis, the fungus diminishes water output from the host plants in the light. An opposite phenomenon can be observed in the dark; water output from infected plants in the dark increases sharply mainly in the stage of advanced fructification. Thus, the fungus considerably diminishes the ratio of water output from the host...