biologia plantarum

International journal on Plant Life established by Bohumil Němec in 1959

Fulltext search in archive



« advanced mode »

 previous    ...   185   186   187   188   189  190   191   192   193   194   ...    next 

Results 5641 to 5670 of 6171:

Trunk contraction ofHevea brasiliensis due to tapping

J. Luštinec, J. Simmer, W. L. Resing

Biologia plantarum 11:236, 1969 | DOI: 10.1007/BF02920802

Determination of bark contraction due to tapping made simultaneously at different positions on the trunk ofHevea trees (young PR 107, S/2 ↓) provided information about the flow area and the speed of contration spreading.
The relation between truck contraction at the given distance from the cut and the amount of latex tapped was experessed in mathematical terms. A quantitative relation was also established between the yields of latex and the linear dimension of flow areas in longitudinal direction below the middle of tapping cut.
From the contraction curves it is deduced that the lateral flow of latex becomes relatively more important with increasing yields.

Hydroxylation reactions in roots of maize (Zea mays L.)

Tatiana Pšenáková, P. Kovács, M. Pšenák, J. Kolek

Biologia plantarum 12:98-104, 1970 | DOI: 10.1007/BF02920886

The authors succeeded in demonstrating accumulation of tyrosine and p-coumaric acid in three day-old roots of maize (Zea mays L.) fed with L-phenylalanine and cinnamic acid. Phenylpyruvic acid applied under the same conditions gave rise to phenylalanine, indicating the presence of the corresponding transferase activity. Even simultaneous application of inhibitors of transaminase activity-hydroxylamine and isonicotinic acid hydrazide-did not result in the formation of p-hydroxyphenylpyruvic acid.

The effect of light intensity on stomatal frequency in leaves ofIris hollandica hort., var. wedgwood

J. Pazourek

Biologia plantarum 12:208-215, 1970 | DOI: 10.1007/BF02920869

Stomatal frequency in leaves of plants of Iris hollandica, cultivated under four light intensities, about 12%, 37%, 75% and 100% of natural daylight, was studied. The stomatal frequency decreases with lower light intensities. The gradients of stomatal frequency of successive leaves show an increase up to the third or fourth leaf with a subsequent decrease of values up to the highest leaf. The total number of stomata per leaf is not constant; differences exist in successive leaves of a shoot as well as among the leaves of plants growing under various light intensities. The character of gradients was changed at lower light intensities. The largest reaction to the light intensity appeared in leaves with higher stomatal frequency. The gradients in individual leaves depend on the insertion of the leaf. Both the shape and the slope of these gradients are influenced by the light intensity.

Use of acid, alkali and enzymes for the extraction of nucleic acids from pollen

J. Süss

Biologia plantarum 12:332-341, 1970 | DOI: 10.1007/BF02922187

Various methods for extracting nucleic acids from pollen were tested to find a suitable procedure for obtaining a pure preparation of nucleic acids uncontaminated by polysaccharides and polyphosphates without the use of ion exchangers. Extraction was carried out with perchloric acid, potassium hydroxide, ribonuclease and deoxyribonuclease, sodium tetraborate, and combinations of these. In all fractions, residues of precipitates and residues of extracted pollen matter, the quantity of RNA, DNA, proteins and concomitants,i.e. Polysaccharides and polyphosphates, was determined. The purity of preparations was checked by means of UV-spectra. The criterion of nucleic acid purity was agreement between the nucleic acid amounts calculated on the basis of measurement of absorption in UV-region, orcinol reaction and content of phosphorus. It was found that in our material only a few methods would be applicable and with great limitation, because many polysaccharides and polyphosphates appeared in nucleic acid fractions.

Cytogenetic studies on the effect of chronic gamma irradiation onVicia faba

Soheir M. Amer, I. Y. Mostafa, Evon Mikhael

Biologia plantarum 11:432-441, 1969 | DOI: 10.1007/BF02920707

Vicia faba seeds (cv. Giza 1) were planted in the Inshas gamma radiation field where they were chronically irradiated during the whole life of the plant. The percentage of the induced abnormal P.M.Cs, as well as the frequency of abnormal P.M.Cs in the different meiotic stages were proportional with the given doses. The main types of chromosome aberrations were anaphase and telophase bridges, fragmentation and lagging chromosomes. The nearest plants to the source showed an inhibition of shoot growth, flower and seed sterility and irregular branching. At the dosage levels used irradiation had no effect on pollen fertility.
Seeds of the 1st filial generation were used for both mitotic and meiotic studies. The percentage of the mitotic abnormalities was proportional with the doses. The most dominant type of anomaly was the presence of micronuclei in the different stages of mitosis and in the resting cells. Irradiation affected also other types of anomaliese.g. lagging chromosomes, fragments, bridges...etc.
Meiosis, and pollen fertility (2nd generation) were normal.

The dynamics of the uptake of unionized [NP(NH2)2]2 by barley plants

L. Ondráček, J. Hampl, W. Waněk

Biologia plantarum 12:71-73, 1970 | DOI: 10.1007/BF02920881

The dynamics of the uptake by barley plants of trimer phosphonitrile-amide [PN(NH2)2]3 labelled with32P was studied. It was shown experimentally that the covalent compound [PN(NH2)2]3 enters the plants more rapidly than (NH4)2HPO4. Hence it was concluded that the mechanisms of the transport of [PN(NH2)2]3 and (NH4)2HPO4 into the cells, across the cell membranes, are different.

The agrochemical effectiveness of some phosphorus-nitrogen compounds with the direct P-N bond

L. Ondráček, Z. Řezáč, F. Moudrý, J. Hampl, W. Waněk

Biologia plantarum 12:159-166, 1970 | DOI: 10.1007/BF02920864

Phosphorus-nitrogen compounds characterized by the direct P-N bond, represented by trimeric and tetrameric phosphorus nitridoamide-[PN(NH2)2]3-4, phosphorus oxytriamide-PO(NH2)3 and ammonium diamidophosphate-NH4PO2(NH2)2, were applied as fertilizers in a vessel experiment with barley and their agrochemical effectiveness was compared with that of ammonium phosphate-(NH4)2HPO4. The results obtained indicate that the above compounds are of nutritive value for plants.

Light regime effect on the growth rate variability ofScenedesmus quadricauda (Turp.) Bréb. Clones originating from cells treated by a mutagen when grown on the surface of a solid medium

J. Nečas

Biologia plantarum 12:281-290, 1970 | DOI: 10.1007/BF02922158

The light regime effect on the growth rate variability of clones of one chlorococcal alga strain growing on the surface of a solid medium was studied from the point of view of the clone selections manifesting the desired grade of this complex character. Several combinations of light regimes used for the cultivation of coenobia treated by UV-light and untreated control on two types of solid media proved the significance of manifestation degree changes of this character due to the given light conditions. The sizes of the alga colonies after a certain growth time on the surface of solid medium were evaluated statistically and the values obtained indicated the degree of growth rate manifested by the clones of a given population. The x and sx values of their growth rate variability were considered as the indicators facilitating the choice of selec-tion type and screening level. This paper is a partial contribution to the solution of the problems concerning the primary selection of alga clones on the surface of solid media.

Precipitation of S, M, X and Y potato viruses by polyethyleneglycols with different molecular weights

Liana Albrechtová, O. Klír

Biologia plantarum 12:31-40, 1970 | DOI: 10.1007/BF02920876

The minimum concentration of polyethyleneglycol (PEG) with molecular weights 4000, 6000, and 15000 necessary for precipitation of S, M, X and Y potato viruses was determined. An excessive amount of PEG causes the precipitation of other protein compounds from potato leaf cell sap. In order to obtain highly purified samples, it is necessary to use just the minimum sufficient amount of PEG. Using the minimum quantity of PEG is, also, advisable from an economical point of view. The minimum concentration of PEG of given molecular weight differs for different potato disease viruses. The concentration of PEG necessary for precipitation of a given potato virus depends on the molecular weight of PEG used-4000, 6000 and 15000. As the molecular weight increases, the concentration of PEG necessary for precipitation decreases.

The amylolytic activity of Ca-deficient pumpkin plants (Cucurbita pepo L.)

M. Dvořák, Vlasta Radotínská-Ledinská

Biologia plantarum 12:117-124, 1970 | DOI: 10.1007/BF02920859

We studied the significance of actual accessibility of ions for presence of α-amylase in roots and cotyledons of young pumpkin plants. We considered α-amylases to be-in agreement with published data-amylolytic enzymes which lose their activity after being dialysed against EDTA or a dilute solution of hydrochloric acid and which can be reactivated by addition of Ca2+. N connection with activity and Ca2+ nutrition appeared in cotyledons; it did, however, in roots: Ca-deficient plants revealed after preparation either completely inactive enzymes or enzymes with slight activity. It was, however, possible to reactivate them by addition of Ca2+ during preparation.
So, using polyacrylamide disc electrophoresis we present evidence for the appearence of amylase with typical characteristics for α-amylases of other sources. Its relative mobility was the same for isolates from both roots and cotyledons. Its biosynthesis was not dependent upon metal which is associated with enzyme. No conclusion can be drawn as to whether Ca-deficient α-amylases are activein vivo; therefore it was impossible to judge whether α-amylase activity is subject to feed-back regulation.

Simple phenolic glycosides as potential regulators of the IAA-oxidase system

M. Pšenák, A. Jindra, P. Kovács

Biologia plantarum 12:241-245, 1970 | DOI: 10.1007/BF02920808

The effect of phenols and simple phenolic glycosides on the activity of IAA-oxidase isolated from gherkin seedlings was studied in experimentsin vitro. Phenol stimulated the enzyme system activity, eugenol and quinol were proven as inhibitors. Simple phenolic glycosides (arbutin, gein and phenol glucoside) influenced IAA-oxidase activity only if β-glycosidase was present: rree phenols released from their bound form increased or decreased the IAA level. The potential fegulatory effect of simple phenolic glycosides on the IAA level in plants has been discussed; this effect is thought to be mediated by free phenols and by influence on the IAA-oxidase system.

The application of growth regulators for the physiological emasculation of rye(secale cereale l.) flowers

Z. Sladký

Biologia plantarum 12:388-394, 1970 | DOI: 10.1007/BF02922301

The present paper deals with the possibility of using growth regulators for the physiological emasculation of rye flowers and utilizes our knowledge of the higher sensibility of stamens to the auxin level. By means of bioassays it has been found that a relatively low content of auxins and a definite level of gibberellins and inhibitors are characteristic for normal rye spikes at the time of stamen differentiation. The higher level of auxins and expressive inhibitions occur in the later course of pistil differentiation.
Two sprayings of plants with mixed solutions of MH and NAA and two further sprayings with a solution of NAA only before the stamen differentiation change slightly the natural character of endogenous regulators in spikes and cause the destruction of mother pollen cells in anthers and the sterility of anthers in the majority of rye florets. The anthers in the basis of spikes sometimes contain pollen grains after treatment, but their fertility is substantially lowered because the spray evidently disturbed the accumulation of reserve substances in pollen grains. The development of pistil was not affected by the exogenous application of growth regulators. Normal kernels arose in the majority of flowers after supplementary pollination. Some accidental effects of exogenous application of growth regulators, as for example reduced stem growth and disorder of lodicule function were lowered to a great extent by adding GAS to the last two sprayings of NAA.

Influence of natural substances of phenolic character and diethyldithiocarbamate on the metabolism of L-tryptophan in cabbage, maize and pea

V. Kefeli, M. Kutáček, Květa Vacková

Biologia plantarum 12:81-90, 1970 | DOI: 10.1007/BF02920854

The effect of phenolic substances isolated earlier from cabbage, maize and pea on L-tryptophan-3-14G (L-Try-14C) metabolism in those plants was investigated. For the sake of comparison the effect of diethyldithiocarbamate (DIECA) on cabbage was also observed. A phenolic substance of unknown structure isolated from cabbage was utilised in a 0.5 mg/ml concentration, p-coumarie acid (PCA) from maize in 0.7 mg/ml concentration and quercetin-glucosyl-coumarate (QGC) found in pea in 8 mg/ml concentration were used. The chosen concentrations were on the limit of their inhibitory effect on the growth of the respective plant apical segments. The effect of DIECA was investigated at 0.1 mg/ml concentration. Using non-labelled L-Try as substrate (5 × 10-3 M) biological tests have shown that QGC and DIECA have a weaker but distinct effect on the increase in auxin level (+ 17% and + 15%, respectively). All phenolic compounds, as well as DIECA increase the intake of L-Try-14C from the incubation solutions. Phenolic substances decrease the conversion of L-Try-14C to its metabolites. The changes were studied after a 20 hour period of L-Try-14C metabolism. On chromatograms changes in the proportion of L-Try-14C metabolites took place, especially in the areas of substances of complex character from which IAA splits off easily,i.e. in the areas of 3-indolylacetylglucose and 3-indolylaeetamide. The radioactivity of these areas is generally decreased (e.g. the decrease of radioactivity in the 3-indolylacetylglucose area under the influence of the phenolic substance ofBrassica plants is -7,4%, under the influence of PCA in maize it is -8.9% and under the influence of QGC in pea it is -17.1% DIECA also decreased the radioactivity of this zone, by -10,5%. In cabbage a large part of L-Try-14C was transformed to glucobrassicin; its biosynthesis increases in the presence of the phenolic substance of cabbage by +3%, in the presence of DIECA by +27%. The results are discussed in a working hypothesis based on the key formation of IAA, accompanied by its oxidation and detoxication.

Prediction of relative efficiency of some selection indices used in winter wheat

J. Smoček

Biologia plantarum 12:216-223, 1970 | DOI: 10.1007/BF02920870

Separate selection indices were constructed for various combinations of selective characters, in which together with components of economic yield also four separate subcharacters, yield prerequisites were used, namely: flag leaf area, length of the flag leaf, angle of the second leaf (from the top) and length of plant at heading time. Maximum genetic advance in weight of grains per plant (yield) from selections may be expected in selection indices in which three economic yield components together with flag leaf area or angle of the second leaf were used.
When as criteria for selection the flag leaf area together with yield components were used, selection indices with six different sets of economic weights for yield and weight of one grain were also computed. For the ratio of economic values 1∶1, the total expected advance was the highest, but separate advance in yield was approximately only 57% in comparing with selection made according to yield as complex character. For the ratio of economic values 1∶0.03 to 1∶0 the expected genetic advances in yield were about 22 and 24 per cent higher in comparing with selections according to yield. It may be expected that yield improvment will not be acquired by means of a great number of small, inferior grains.

Transport, localization and physiological effect of 6-benzyladenme-8-14C in apple shoots

A. Friedrich, L. Chvojka, R. Bulgakov, J. Kolín

Biologia plantarum 12:342-347, 1970 | DOI: 10.1007/BF02922188

The transport of radioactivity of 6-benzyladenine-8-14C applied to one-year old apple shoots was studied. Simultaneously, labelled metabolites of this cytokinin were studied separately in the xylem and phloem above and below the place of application. According to the results obtained, it can be assumed that 6-B and its metabolites are transported in one-year old apple shoots acropetally through the xylem and basipetally through the phloem, while penetrating from the xylem to the phloem. Besides 6-B-8-14C, a complex of cytokinin with sugar, also adenosine and adenine were found in the phloem.

Distribution of tin in shoots of horse chestnut (Aesculus hippocastanum L.)

Milada Rottová

Biologia plantarum 12:74-77, 1970 | DOI: 10.1007/BF02920882

Seedlings of horse chestnut (Aesculus hippocastanum L.) originating from two different localities were cut into several parts in which the tin content was estimated. When expressed per dry weight unit the vegetative parts of plants contain about 9 μg Sn per g dry weight, its content in apical parts of stem and root being still higher. This gives evidence of good mobility of tin in the plant.

Pea growth and ion accumulation at varying seed density

Z. Laštůvka, J. Minář

Biologia plantarum 12:167-179, 1970 | DOI: 10.1007/BF02920865

Decreased accumulation of elements, particularly of nitrogen, had in dense stand a negative influence on the plants, in spite of the supply of fresh solution and the control of the concentration of nutrients in the pots. The fresh weight and the dry matter of one plant were reduced substantially with rising stand density (from 5 to 10, 20, 40 and 80 plants per 450 sq. cm); the RGR value, the relative absorption rate IM, the content of all tested elements calculated per one plant, the chlorophyll content in the overground parts of one plant, and the distribution index decrease. Qualitatively the same influence is caused by deficiency of nutrients. Plant dying and self-thinning of the culture occurred in denser stand in the course of cultivation. The root-weight ratio rose with stand densification, particularly at the end of the experiment. The net assimilation rate (NAR) related to chlorophyll dropped with stand density; NAR at density "80" rose slightly from the 22nd day of cultivation and did so at further lower densities. Almost all NAR values lie over the control value at the last measurement. The chlorophyll content in mg g-1 dry matter of the overground parts rose with stand density to density "40" (41% more than at density "5"); afterwards it dropped. The accumulation (in mg g-1 d.m.) of phosphorus ions was higher in the plants from dense cultures compared with density "5", particularly in the roots. The accumulation of potassium was near to the control value ("5"), while that of nitrogen was lower. The utilization quotients of phosphorus and potassium in denser stands were the same or negligibly lower than at density "5". They were a little higher in nitrogen than in the controls. Also the ratio RGR/IM was a little higher than in denser stands. The root-weight ratio, the accumulation of elements in mg g-1 d.m., the chlorophyll content in mg g-1 d.m., NARch, the utilization quotient, and the ratio RGR/IM differed qualitatively by the densification of the culture (with complete mineral nutrition) from the influence of element deficiency (at the same stand density).

Sensitivity of apple seed germination to light and some growth regulators

St. Lewak, Krystyna Bialek, Irena Sińska

Biologia plantarum 12:291-296, 1970 | DOI: 10.1007/BF02922159

Experiments were aimed at checking whether the non-stratified apple embryos are sensitive to growth factors and light. The effect of growth regulators on light sensitivity was also studied. The stimulating or inhibiting effect of GA3, benzyladenine and IAA or coumarin on the dynamics of apple embryo germination was demonstrated. Seasonal fluctuations of the effect of the growth factors were noted. The stimulating effect of light on the germination of non-stratified apple embryos was demonstrated. This effect is independent of season and seems to be independent of the effects of growth regulators.

Studies on growth and utilization of stylar carbohydrate by pollen tubes and callose development in self-incompatibleOenothera organesis

S. Kumar, A. Hecht

Biologia plantarum 12:41-46, 1970 | DOI: 10.1007/BF02920877

The addition of boric acid or calcium, or both boric acid and calcium to the warm water in which the styles were treated led to a further enhancement of pollen tube growth in otherwise incompatible styles.
It was established that developing pollen tubes ofOenothera organesis obtain sugar from the stylar tissue through which they grow. The rate of this utilization of endogenous sugar was stimulated by the addition of boric acid.
It was further established that with increased pollen tube development there was reduction in callose plugs as well as in content of endogenous stylar sugar.

Growth correlations inBryophyllum leaves and exogenous growth regulators

R. Dostál

Biologia plantarum 12:125-133, 1970 | DOI: 10.1007/BF02920860

Growth correlations in leaves ofBryophyllum may be recognized by the development of marginal shoots varying in their particular lamina regions, the correlative inhibition increasing from the top to the base. Cytokinins extend their promoting action inB. crenatum leaves farther in the apical than in the basal direction. In the uppermost leaves ofB. daigremontianum they evoke the development of marginal shoots with flowers in the apical and of vegetative shoots in the basal region. Less suitable for this research are auxins, gibberellins, and triiodobenzoic acid which are unable to stimulate the development of marginal shoots on leaves grown out under short days if not supplemented by cytokinins. Only TIBA induces under long days formation of adventitious shoots directly from the lamina surface on leaves developed below the terminal ring fasciation exhibiting at free ends of connate leaves normal marginal shoots. Under short days a complete reduction of lateral teeth takes place inB. verticillatum both on the extremity of ring fasciation and on the uppermost leaves, the marginal shoots being formed under the subsequent long days only in the angles between the ring fasciation parts. Furthermore the correlative inhibition of the leaf causes anisophylly in marginal shoots in the same way as that of axillaries inBryophyllum.

Pathways of IAA production from tryptophan by plants and by their epiphytic bacteria: Metabolism of indolepyruvic acid and indolelactic acid

E. Libbert, K. Brunn, Anneliese Drawert, Roswitha Schröder

Biologia plantarum 12:246-255, 1970 | DOI: 10.1007/BF02920809

Metabolites of indolepyruvic acid and indolelactic acid were investigated using 2 systems: a bacterial (pea stem homogenates containing the epiphytic bacteria) and a plant system (pea stem sections under sterile conditions). The products of spontaneous indolepyruvic acid decomposition in aqueous solution and during chromatography were investigated, too.
Biological indolepyruvic acid conversion yields, besides those substance amounts which occur spontaneously, indoleacetic acid, indoleethanol (tryptophol) and (only in the sterile plant system) indoleacetaldehyde. An inhibitor extract from pea stems decreases the indoleacetic acid and increases the indoleethanol and indoleacetaldehyde gain.
Indolelactic acid is not metabolized in the sterile plant sections. Indolelactic acid oxidation by the bacteria-containing homogenate yields indolepyruvic acid and is inhibited by the inhibitor extract.

Effect of decreased rate of water absorption on water balance of leaf tissue

Jana Pospíšilová

Biologia plantarum 12:395-400, 1970 | DOI: 10.1007/BF02922302

The influence of decrease of water absorption rate on the transpiration rate and the development of water saturation deficit (WSD) was studied on the leaf segments of kale. Solutions of polyethyleneglycol (0-25m, 0-50m, O-75m and 1-00m) and mannitol (0-50m) were used as osmotic agents.
The rate of water absorption decreased to zero when the concentration of polyethyleneglycol was 0-25m. At a concentration higher than 0-50m, water from the tissue diluted the external solution. The transpiration rate of samples affected by polyethyleneglycol or mannitol was only a little lower than that of control samples. WSD was noticeably increased only in the absorbing part of segment; in the adjoining, transporting part of segment WSD was practically the same in all variants. WSD in the transpiring part was slightly increased only in some cases. Due to decrease of osmotic potential of the external solution also the gradient of water potential changed. In the case of absorption from pure water, water potential gradually decreased from the absorbing to the transpiring part. Under the influence of polyethyleneglycol or mannitol solution the highest water potential was in the transporting part and from this point water potential decreased to both opposite sides.

Development of embryoids in carrot root callus culture (Daucus carota L.)

Eva Petrů

Biologia plantarum 12:1-5, 1970 | DOI: 10.1007/BF02920872

Embryogenesis occurred in carrot root callus (Daucus carota L.) cultivated on simple synthetic medium containing IAA and 2,4-D. Embryoid development continued also during successive years when the tissue was cultivated on the same nutrient medium without those substances. Sometimes production of plants with atypical leaves was also observed. In those plants development of adventive embryoids occurred repeatedly. Result of this work confirmed reports about the organogenic potentiality of this species and about its sensitivity to some chemical substances.

Changes in peroxidase activity in leaves of wheat and barley after infection with obligate parasites

H. Klusák

Biologia plantarum 12:224-230, 1970 | DOI: 10.1007/BF02920871

A study was performed on the influence of obligate parasitesErysiphe graminis Dc. andPuccinia hordeiOtt4 on peroxidase activity in barley leaves, namely in both susceptible and resistant varieties. Attention was also paid to peroxidase activity in a susceptible wheat variety infected withPuccinia striiformisWest.
The following results were obtained:
In leaves of wheat and harley plants an enzyme was revealed which oxidized pyrocatechol and guajacol only in the presence of hydrogen peroxide. This enzyme can be inactivated by heating and strongly inhibited by cyanide. Evidently peroxidase is concerned.
Peroxidase in susceptible varieties of wheat and barley is markedly activated after infection with parasites mentioned above, this activation reaching maximum at the periode of parasite sporulation. On the other hand the barley varieties resistant toE. graminis andP. hordei, exhibit only a slight or no increase in peroxidase activity at this period. Thus we come to the conclusion that peroxidase does not probably appear to be the cause of the resistance of these varieties. It seems that in tissues attacked by obligate-parasites the intensity of its activation can be a result of the infection intensity.

Effect of β-indoleacetic acid, maleic hydrazide, and 2,3,5-triiodobenzoic acid on N, P, K, and Ca accumulation by pea plants

Alena Raková, J. Minar

Biologia plantarum 12:348-358, 1970 | DOI: 10.1007/BF02922189

A study was performed on the effect of various concentrations of IAA, 2,3,6-triiodobenzoic acid, and maleic hydrazide, supplied to Richter's nutrient solution, on growth of pea plants in water cultures. After a 18-day cultivation growth was evaluated and in the plants gathered the content of total N, P, K, and Ca was estimated.
Growth of experimental plants (as evaluated from fresh and dry weight) was affected by all three regulators in dependence on the concentration used. It was stimulated by lower concentrations and inhibited by higher, the production of both fresh and dry weight of the root system being stimulated by all IAA concentrations used.
The ratio of root dry weight to that of the entire plant was markedly increased after application of IAA and 2,3,5-triiodobenzoic acid, whereas when applying maleic hydrazide it was only slightly increased in comparison with control.
Stimulation or inhibition of growth induced by IAA treatment was accompanied by an accordingly increased or decreased accumulation of N, P, K, and Ca. Thus their utilization did not change in comparison with control. On the other hand, both inhibitory and stimulatory effects of 2,3,5-triiodobenzoic acid and maleic hydrazide on growth were associated with a relatively lower accumulation of the elements in question, resulting in an increased utilization.
The distribution index of N, P, K, and Ca decreased with increasing concentrations of IAA, 2,3,5-triiodobenzoic acid and maleic hydrazide. Only the highest 2,3,5-triiodobenzoic acid and maleic hydrazide concentrations used brought about a more marked increase in the distribution index of potassium, simultaneously with a marked decrease in the distribution index of calcium.

Inhibitory ability of sap from different tobacco varieties on potato virus Y

J. Chod, J. Polák, J. Čermák, K. Škula

Biologia plantarum 11:79, 1969 | DOI: 10.1007/BF02920733

In these experiments the inhibitory ability of 12 varieties ofNicotiana tabacum L. to potato virus Y was studied by means of drop serological precipitation method. In 11 varieties under study a correlation was found between field resistance and the inhibitory ability of sap. Varieties S 390/1, line 40, fixed A 1 exhibited low inhibitory ability of sap, lines Bel 61-10, R 3, Criolo and Burley N-15 were of medium inhibitory ability and high inhibitory ability was found in varieities Viržinský zlatý, line 37, A 5205 and R 1. The variety Viržinský zlatý, which is believed to be susceptible to potato virus Y was found to have high inhibitory ability. This was confirmed by inoculation of leavesChenopodium giganteum Don., determination of the number of lesions by the half leaf test, and determination of relative concentration of potato virus Y by means of serological drop method. None of the varieties under study showed extremely high inhibitory ability against potato virus Y.
We believe that laboratory methods of determining the inhibitory ability of sap of tobacco leaves can be used to produce hybrids with high inhibitory ability on potato virus Y. The field resistance of those hybrids should, however, be checked by provocative field experiments.

Role of growth regulators in differentiation processes of maize (Zea mays L.) organs

Z. Sladký

Biologia plantarum 11:208, 1969 | DOI: 10.1007/BF02920799

The following paper deals with the character of endogenous auxins and gibberellinlike substances in the maize tassel and ear primordia during differentiation. Using bioassay the character of substances extracted from tassel primordia, internodes below the tassel, ear primordia and stem base was determined and correlated with the course of morphogenesis and differentiation. A low level of auxins and a high content of gibberellin-like substances accompanies the differentiation of terminal tassel. The differentiation of an ear is associated with an increment in auxin content while the level of gibberellin-like substances decreases. The character of growth substances in primordia remains practically unchanged in the course of further differentiation. The inhibitions appear in the plant and probably start numerous morphological reductions in the pistillate inflorescence structure or inhibit the growth of lateral primordia on the stemetc. The treatment of plants with maleic hydrazide at the beginning of tassel differentiation shifts the normal levels of endogenous regulators and brings about the transformation of tassel primordia into an ear. This transformation is accompanied by a marked rise in gibberellin-like substances, by an increment in auxins and the appearance of inhibitors.

The dependence of the frequency of recessive lethal and vital mutations inArabidopsis thaliana (L.)Heynh. on the concentration of N-nitroso-N-methylurea

Milena Riesová-Kučerová

Biologia plantarum 11:338-346, 1969 | DOI: 10.1007/BF02921398

The dependence of the frequency of recessive lethal (two groups), chlorophyll and morphological mutations on the mutagen concentration was determined in M2 after subjection to N-nitroso-N-methylurea applied to seeds ofArabidopsis in three concentrations (0.05, 0.10 and 0.20mm). The observed frequencies were compared with the theoretically expected ones for the linear and for two exponential types of dependence, by using the t-test, according to the formulas m=k. C, m=k. C3/2, m=k. C2. No satisfactory agreement with any expected type of dependence was found when directly observed frequencies were used. Since a considerable deficit of mutation frequency was observed in high concentrations, the correction of frequency values was done with respect to the probability of occurence of double mutations. After such a correction, a clear exponential relation was found in both types of lethals and a linear one in chlorophyll and morphological mutations. The probable occurence of multiple mutations should be, therefore, taken into account if the dependence of mutation frequency on the concentration of mutagen is discussed.

The participation of flavine enzymes in the respiration of root zones of the horse bean (Vicia faba L.).

Věra Hadačová, M. Dvořák

Biologia plantarum 11:450, 1969 | DOI: 10.1007/BF02920709

As part of our studies on respiration systems in root zones of the horse bean (Vicia faba L., cv. Chlumecký) the influence of quininehydrochloride and potassium cyanide on respiration was followed. The inhibition of the oxygen uptake by quininehydrochloride was highest in the elongation zone and lowest in the meristematic zone. Thes shows that the flavine enzyme content is lowest in the meristem, highest in the elongation zone. The inhibition of Fe- and Cu-enzymes by KCN increases from the root tip towards the older parts of the root, but is lower than the inhibition by quininehydrochloride. The difference between the intensity of action of both, applied separately, and of the combined effect of both if compared with the action of cyanide alone, is highest in the elongation zone; this shows that relatively higher amounts of non-metallic flavine enzymes participate in this zone. Their relation to the pentose phosphate cycle is discussed.

Dependence of radiostrontium uptake by pea and lupin on the content of calcium in the nutrient solution

J. Balcar, Alena Březinová-Doškářová, J. Eder

Biologia plantarum 11:34-40, 1969 | DOI: 10.1007/BF02920728

In lupin (Lupinus albus L.) and pea (Pisum sativum L., cv. Raman) it was shown that the uptake of89Sr from Knop's nutrient solution is significantly increased from a solution with decreased calcium content (one tenth of the normal content) and is slightly decreased from a solution with higher calcium content (150% of the normal content). The calciphile pea absorbs approximately 50% more calcium than the calciphobe lupin, and accordingly 50% radiostrontium less. The pea plant more strongly blocks the translocation of radiostrontium from roots to overground parts, as is proved by the higher discrimination factor of pea (i.e. by the ratio of specific activities of mCi89 Sr/g Ca of roots to overground parts). The presence of chlorine in the nutrient solution decreases the content of radiostrontium per gram of dry matter, both in pea and lupin. Radiostrontium is absorbed quickly by both species of plants and is autoradiographically detectable as early as 2 hours after the introduction of radiostrontium to the nutrient solution. *** DIRECT SUPPORT *** A01GP049 00004

 previous    ...   185   186   187   188   189  190   191   192   193   194   ...    next