Heterogeneity of the content of endogenous gibberellins in the leaves of winter wheat in relation to their insertion and ontogeny

Zuzana Jureková, J. Repka

Biologia plantarum 15:305-311, 1973 | DOI: 10.1007/BF02922441

Free and bound gibberellins were estimated in individual leaves of winter wheat using TLC a lettuce hypocotyl bioaasay. Bound gibberellins were extracted from the hydrolyzate of the water remnant after the removal of free gibberellins.Each leaf exhibits its own dynamics of free and bound gibberellins during its individual ontogeny, the gradual changes tending to be identical in every leaf. In young developing leaves the level of free gibberellins is high and that of bound is low. Further, inhibitors are sometimes present. The free gibberellin level rises with the activisation of growth and vital activity of a given leaf. Towards the end of the...

Uptake of Sugars by Tobacco Callus Tissue

Miroslava Opekarová, A. Kotyk

Biologia plantarum 15:312-317, 1973 | DOI: 10.1007/BF02922442

D-Glucose and several other sugars are taken up by slices of callus tissue ofNicotiana tabacum and are both oxidized to CO₂ and incorporated into tissue components. The uptake as well as the subsequent metabolism are slow, the transport process being characterized by lack of specificity, no hyperbolic saturation, no influence of metabolic or transport inhibitors and hardly any dependence on pH. The apparent activation energy of the process was about 42 kJ mol^-1. It appears that the transport proceeds by simple diffusion through narrow intercellular spaces and possibly hydrophilic pores and that only about 10% of the tissue...

Cytokinin activity of some derivatives of n- n- butyl- n' - aryl thiourea and their effect on the nitrogen metabolism in barley seedlings

N. P. Mashev, G. N. Vassilev

Biologia plantarum 15:318-323, 1973 | DOI: 10.1007/BF02922443

The cytokinin activity of a group of derivatives of N-n-butyl-N'-arylthiourea and their effect on the uptake of amino acids and the accumulation of total nitrogen in seven-day barley seedlings have been investigated. It was established that N-n-butyl-N"-2,4-dinitrophenyl-thiosemicarbazide, N-n-butyl-N'-o-,m- andp-chlorophonylthioureas, N-n-butyl-N'-3,4-dichlorophenylthiourea and N-n-butyl-N'-2-methyl-4-ehlorophenylthiourea possess a high activity with respect to the retardation of the chlorophyll breakdown. Substances with a high cytokinin activity cause an increase in the amount of total nitrogen and amino acids, mainly of glutamic...

The relationships between quantitative characteristics of stomata and epidermal cells of leaf epidermis

J. Kutík

Biologia plantarum 15:324-328, 1973 | DOI: 10.1007/BF02922444

Negative linear correlations were established inMagnolia soulangeanaSoul. -Bod. andLigustrum vulgare L. leaves between the frequency and the size (length) of the stomata and between the frequency of the stomata and the area of epidermal cells. Most correlations were statistically significant at theP = 0.01 level. Positive linear correlations were established between the area and the thickness of epidermal cells. These correlations were near to theP = 0.05 level of statistical significance. A high variation coefficient "v%" of the total number of stomata per leaf was found in both plant species.

Changes in nucleic acid synthesis in cotyledons and apical buds of chenopodium rubrum l. associated with photoperiodic induction

Lola Teltscherová

Biologia plantarum 15:329-334, 1973 | DOI: 10.1007/BF02922445

The nucleic acid (NA) fractions were analyzed in cotyledons and apical buds ofChenopodium rubrum plants by means of acrylamide electrophoresis at the end of the dark period of a different number of photoperiodic cycles or after transfer of the plants to light for 4 h subsequent to the termination of the dark period. The plants were labelled with³²P three hours prior to sampling. The uptake of³²P into the cotyledons was higher in light than in darkness in all cases, however, it was not in correlation with³²P incorporation into the NA fractions. After one dark period lasting 8 or 16 h NA synthesis in light did...

Response of nicotinamide adenine dinucleotide and cytochromes to aerobiosis and anaerobiosis on addition of glucose to saccharomyces cerevisiae

G. F. Israelstam

Biologia plantarum 15:335-338, 1973 | DOI: 10.1007/BF02922446

When aerated suspensions of whole yeast cells were either made anaerobic or were supplied with substrate (glucose), changes in absorption occurred which indicated cytochrome reduction. No such change was observed on addition of substrate to anaerobic suspension of yeast. These results were confirmed by obsevations of changes in absorbance at a series of fixed wavelengths corresponding to the reduced absorption peaks of cytochromesa, b andc. NAD* on the other hand was reduced on addition of substrate under both aerobic and anaerobic conditions. These results are discussed in relation to the possible role of NAD* in the Pasteur Effect.

Isoperoxidases in jerusalem artichoke in relation to tuberization and dormancy

Th. Gaspar, Catherine Teppaz-Misson, J. C. Courduroux

Biologia plantarum 15:339-345, 1973 | DOI: 10.1007/BF02922447

Peroxidase activity and isoenzyme pattern were investigated in buds and tubers of Jerusalem artichokes in relation to induction and breaking of dormancy. Peroxidase activity per unit soluble protein is the highest in the dormant stage. Conditions leading to growth,i.e. release of dormancy by the cold, stimulation of axial growth by gibberellic acid or stimulation of radial growth (tuberization) by kinetin, cause rapid loss of total peroxidase activity together with a decrease of intensity of the most cathodic isoperoxidases. Induction of dormancy by AMO-1618 increases peroxidase activity mainly through the same cathodic isoenzymes. The role...

Book reviews

J. Čatský, Vlasta Čatská, Ingrid Tichá, Ingrid Tichá

Biologia plantarum 15:366-368, 1973 | DOI: 10.1007/BF02922454

The regulation of glutamate dehydrogenase isoenzymes by nitrite in isolated pea roots

Věra Hadačová, J. Sahulka

Biologia plantarum 15:346-349, 1973 | DOI: 10.1007/BF02922448

Unmetabolized nitrite occurs in 3 cm long apical segments of primary pea roots(Pisum sativum L., cv. Raman), isolated from 6 d old seedlings, grown under aseptic conditions for 10 h in nutrient solutions containing 0.1 to 2 mM nitrite concentration, its amount being dependent on the concentration in the nutrient solution. With increasing amount of nitrite in the roots, the ratio between NAD⁺-GDH₁ and NAD⁺-GDH₂ isoenzymes is changed without influencing significantly the total NAD⁺-GDH activity. After 48 h cultivation unmetabolized nitrite occurred in the roots only in small amounts and the...

Toxic and genetic factors limiting the increase of mutation frequency after treatment by alkylating nitroso- compounds and x- rays on arabidopsis seeds

T. Gichner, J. Velemínský

Biologia plantarum 15:350-353, 1973 | DOI: 10.1007/BF02922449

The high M₁ sterility is the factor limiting the increase of the mutation frequency after treatment with nitrosamides like N-methyl-N'-nitro-N-nitrosoguanidine, N-methyl-N-nitrosourea, N-methyl-N-nitrosourethane and N-ethyl-N-nitrosourethane, whereas for ethylvinylnitrosamine-treatment the limiting factor is the toxic action on the M₁ seed germination. The decrease of mutation frequency at high dimethylnitrosamine doses is explained by the inhibition of enzymes or enzyme-like system which hydroxylate nitrosaminesin vivo and thus enable the production of a mutagenic alkylating intermediate. The increase of mutation frequency...

Root water potential in polycormon plants

Jiũina Slavíková

Biologia plantarum 15:354-357, 1973 | DOI: 10.1007/BF02922450

Water potential of roots was measured by thermocouple psyohometers in a series of two or more plants ofCynodon dactylon (L.)Pers. interconnected by overground stolons and thus forming one s.c. polycormon. Root water potential was lowest (most negative) in the oldest "mother" plant and increased in younger individua to highest walues in the youngest "doughter" plants. This gradient of root water potential was found although the "mother" plants continued to be watered while watering all daughter plants had been stopped one week before the water potential was measured. Thus the whole polycormon consisting of a series of interconnected individua...

Parameters of spiral oscillations as indicating the efficiency of control system of growing roots

M. Spurný

Biologia plantarum 15:358-360, 1973 | DOI: 10.1007/BF02922451

The efficiency of the geocontrol system of pea and. maize roots was compared on the basis of their oscillation movements. The rate of elongation of maize roots is 3.6 times higher, the amplitudes of oscillation deviations are 10 times lower and their frequency is 5 times lower than the corresponding values recorded for pea roots. The period of time which elapses between the stimulus and growth response, i.e. the geotropic reaction time, is 4 times shorter in maize roots than in pea roots. The maize root is able to correct the direction of its elongation 3.5 to 5 times more frequently than the root of pea. This characterize the difference between the...

Time-dependence of auxin and ethrel effects on flowering in chenopodium rubrum L.

Saleema Khatoon, Frideta Seidlová, J. Krekule

Biologia plantarum 15:361-363, 1973 | DOI: 10.1007/BF02922452

IAA, NAA and ethrel (1 × 10^-4M and 3 × 10^-4M) was applied to the plumula of Chenopodium plants at different time after the start of photoperiodic treatment and the flowering response was investigated. The inhibitory effect was found with all the applications during the first two days, whereas a stimulatory one on the third and fourth day. We assume this dual effect reflects the differences attained in developmental phase and in the degree of shoot apex differentiation.

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

J. Chod, J. Polák, M. Novák, M. Jokeš

Biologia plantarum 15:364-366, 1973 | DOI: 10.1007/BF02922453

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.jaggeriHelm., cv. Pražan). 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.