A kinetic study of phosphorus absorption by excised maize roots from flowing solutions with different phosphorus concentrations

Radmila Čížková-Macůrková, Z. Laštůvka

Biologia plantarum 17:385-391, 1975 | DOI: 10.1007/BF02921046

The effect of two different mechanisms of phosphorus ion transport from the nutrient solution volume to the surface areas of excised maize roots was studied under concentrations ranging from 0.01 mM to 50.0 mM KH₂PO₄. A modified technique of study of kinetic ion absorption was used. In the control series, the roots were placed in absorption solution without flow (the dominant mechanism of ion transport to the roots being diffusion), while in the experimental series the absorption solution was flowing round the roots at a rate of 0.162 cm s^-1 (the dominant mechanism of ion transport to the roots being mass flow). The...

Development of water stress in kale leaves of different insertion levels

Jana Pospíšilová

Biologia plantarum 17:392-399, 1975 | DOI: 10.1007/BF02921048

The mutual relationship between the water potential (γ _w ), its components, namely the osmotic potential (γ _s ) and the pressure potential (γ _p ), and the water saturation deficit (ΔW _sat ) were determined in the leaves of different insertion levels. During the water stress development in kale plants induced by decreasing soil moisture theγ _w decreased, parallely in all the leaves but the same decrease ofγ _q was accompanied by the highest decrease of theγ...

Transpiration rate and intercellular diffusive resistance in the tobacco leaf

B. Slavík

Biologia plantarum 17:400-404, 1975 | DOI: 10.1007/BF02921050

The increase in the measured transpiration rate in tobacco leaves due to the experimentally decreased humidity of the bulk air was found to be significantly lower than the theoretical value calculated from the change of water vapour concentration gradients. Boundary layer and stomatal diffusive resistances remained unchanged under experimental conditions with no change of net photosynthetic CO₂ uptake. This suggests an increase in intercellular diffusive resistance with an increase in water vapour concentration gradient which is the driving force of water vapour diffusive part of transpiration flux.
The increase can be ascribed to the...

A closed system for measurement of photosynthesis, photorespiration and transpiration rates

J. Čatský, Ingrid Tichá

Biologia plantarum 17:405-410, 1975 | DOI: 10.1007/BF02921051

An installation is described enabling measurements of photosynthesis, transpiration and dark respiration, and estimation of photorespiration rates at different carbon dioxide and oxygen concentrations, at different irradiances and leaf temperatures.

Comparison of the changes in net photosynthetic CO₂ uptake and water vapour efflux during leaf ontogenesis with the differences between the leaves according to their descending insertion level

J. Václavík

Biologia plantarum 17:411-415, 1975 | DOI: 10.1007/BF02921052

The differences between leaves of different age according to their descending insertion level (starting from the youngest, 18th leaf) were compared with the changes occurring during the corresponding period of ontogenesis of the 18th unshaded leaf using the gas exchange [net photosynthetic CO₂ uptake (P _N ), water vapour efflux (E)] of the adaxial and abaxial surfaces of tobacco leaves as an example. Experimental elimination of the influence of shading during the involved period of ontogenesis of the 18th leaf manifested itself by a relatively slower decrease inP _N and by fluctuation...

The effect of synchronizing dark period on populations ofScenedesmus quadricauda

V. Zachleder, J. Doucha, Eva Berková, I. Šetlík

Biologia plantarum 17:416-433, 1975 | DOI: 10.1007/BF02921054

Populations ofScenedesmus quadricauda grown in a continuous chemostatic regime and synchronized by light and dark intervals were exposed to continuous illumination. The effect of light on synthetic and reproduction processes during the time of the omitted dark period and in the subsequent cell cycle was studied. In general, the sequence of cellular processes and their mutual coupling remain the same as in the darkened population. Synthetic processes and photosynthetic activity are depressed during the period of protoplast fission also in the light. The synchronizing effect of the dark period in chlorococcal algae consists in reducing the developmental...

Transpiration in seven plant species colonizing a fishpond shore

J. Květ

Biologia plantarum 17:434-442, 1975 | DOI: 10.1007/BF02921056

In 7 species (Eleocharis palustrisR. Br.,Juncus bufonius L.,Gypsophila muralis L.,Trifolium repens L.,Agrostis stolonifera L.,Potentilla anserina L. andAchillea millefolium L.) growing in a gradient of habitats from aquatic to terrestrial, on a sandy fishpond shore in Southern Bohemia, Czechoslovakia, the daily course of transpiration rate and water content was assessed gravimetrically in their cut-off transpiring parts on two typical summer days. Transpiration rate was largely controlled by microclimate but depressions occurred inJuncus and in some species growing in the drier habitats. The highest...

Free nucleotides in the primary root of maize

Viera Finocchiaro, J. Kolek

Biologia plantarum 17:443-447, 1975 | DOI: 10.1007/BF02921057

Free nucleotides of the primary root of maize were extracted with 5% HClO₄ and separated on a column of Dowex 1×8 ion exchanger in HCOO^- cycle. A two-step elution gradient (HCOOH, HCOOHNH₄) was used for the elution of the nucleotides. The incorporation of³²P into the nucleotides was followed at different time intervals and also in young and more mature root tissues. The nucleotides AMP, GMP, ADP, GDP, and ATP were identified. Labelled phosphorus was found in ATP after 30 s, in ADP after 3 min, and in AMP after 5 min incubation of the roots. More mature roots (18 days) contained higher amounts of AMP than...

Glucose-6-phosphate dehydrogenase in tobacco callus strains differing in their growth and their requirement for auxin and cytokinin

Věra Hadačová, M. Kamínek, J. Luštinec

Biologia plantarum 17:448-451, 1975 | DOI: 10.1007/BF02921058

The cytokinin-autonomous strain (A_s) of tobacco callus differs from the original cytokinin-dependent strain (D) and from the cytokinin- and auxin-autonomous strain (A₄) by a significantly lower activity of glucose-6-phosphate dehydrogenase (G-6-PDH). Changes in the total G-6-PDH activity were associated with differences in the number of G-6-PDH isozymes. The A_s strain contained only one isozyme, four isozymes were found in D and A₄ strains.

Brown rot of wood as a model for studies of lignocellulose humification

V. Rypáček, Marie Rypáčková

Biologia plantarum 17:452-457, 1975 | DOI: 10.1007/BF02921059

Humus substances synthesis was investigated in the course of birch wood decomposition by a brown-rot fungusPiptoporus betulinus. With progressing decomposition of wood by brown rot the proportion of high molecular weight humic acids is gradually increased at the expense of fulvic acids, the amount of which is proportionally lowered. The high molecular weight humus constituents are not accumulated in wood decomposed by a laccase producing white-rot fungi despite the availability of suitable phenolic substrates; the low molecular weight fraction of fulvic acids is permanently higher than the fraction of humic acids. The function of laccase in...

Chemotropic effect of metal cations onSinapis alba L. roots as affected by some factors

Z. Konarzewski, S. Gumiński

Biologia plantarum 17:458-467, 1975 | DOI: 10.1007/BF02921061

Chemotropic effects exerted by metal cations have been investigated simultaneously with their influence on the increments ofSinapis alba roots cultivated in dark and light. The effects of Na-EDTA and Na-humate and its fractions, as well as the interaction of these substances with cations have also been studied. Chemotropics have been administered in agar-agar to the ends of roots growing on glass plates. Chemotropic and growth effects were exerted by Cu²⁺, Fe²⁺, Fe³⁺ and Ca²⁺ cations. The light strongly changed the effects of all but Cu²⁺ cations. Both Na-EDTA and humante appeared to be...

The influence of humic acids on phytase activity isolated from wheat seeds

F. Pospíšil, Marie Hrubcová

Biologia plantarum 17:468-474, 1975 | DOI: 10.1007/BF02921062

Humic acids can inhibit the activity of wheat phytase in model experiments, because they are able to form complexes with hexainositol phosphates and have considerable adsorption properties. Decarboxylated humic acids do not show any inhibitory effects.

The effect of simultaneous short term action of streptomycin and humate on plants

S. Lhotský

Biologia plantarum 17:475-480, 1975 | DOI: 10.1007/BF02921063

Humate (10 mg l^-1) supplemented to streptomycin solutions (0.1 and 1 mM) stimulates growth of germinating wheat and barley grains and of apical cuttings ofCrassula portulacea after 24 h treatment. It does not, however, prevent formation of albinic leaves. Albinism induced by the streptomycin alone and by streptomycin in presence of humate is irreversible and can be removed neither by an iron salt nor by a chelate added to the nutrition solution or applied on the leaves. Cells of plants treated with streptomycin and humate are larger than those of plants treated with the streptomycin alone. The same is true for plastids which in both...

Cushing, D. H.: The productivity of the sea

P. Javornický

Biologia plantarum 17:391, 1975 | DOI: 10.1007/BF02921047

Kessel, R. G., Shih, C. Y.: Scanning electron microscopy in biology. A students' atlas on biological organization

Ingrid Tichá

Biologia plantarum 17:399, 1975 | DOI: 10.1007/BF02921049

Etherington, J. R.: Environment and plant ecology

J. Čatský

Biologia plantarum 17:415, 1975 | DOI: 10.1007/BF02921053

O'Connor, M., Woodford, F. P.: Writing scientific papers in English

J. Čatský

Biologia plantarum 17:433, 1975 | DOI: 10.1007/BF02921055

Street, H. E. (ed.): Tissue culture and plant science 1974

J. Tupý

Biologia plantarum 17:457, 1975 | DOI: 10.1007/BF02921060