Showing papers in "Biologia Plantarum in 1976"
61 citations
TL;DR: In this article, a method of extrapolation of the results obtained by measuring an individual xylem segment against the whole tree and of interpolation to a unit segment is elaborated, a simplified method of connecting the electrodes supplying the thermal input to the segment is described and an indicator of the relative water content of the xylm was derived.
Abstract: Several improvements of the method of sap flow rate determination in full-grown trees elaborated by the authors are described. The method is based on heat balance with direct electrical heating of the xylem. The accuracy of the relationship for the calculation of flow rate was improved, the influence of unevennesses of flow in different annual rings was reduced. A method of extrapolation of the results obtained by measuring an individual xylem segment against the whole tree and of interpolation to a unit segment was elaborated, a simplified method of connecting the electrodes supplying the thermal input to the segment is described and an indicator of the relative water content of the xylem was derived.
59 citations
TL;DR: The characteristic micromorphology of the tobaoco cell strains, or its cyclic changes in the course of the subcultivation interval can be affected by auxin composition of the medium,i.e. by the application of either 2,4-D alone, or NAA, or their combination.
Abstract: The characteristic micromorphology of the tobaoco cell strains, or its cyclic changes in the course of the subcultivation interval can be affected by auxin composition of the medium,i.e. by the application of either 2,4-D alone, or NAA, or their combination. On omitting one of the auxins, the over-all growth of the cultures is not substantially affeoted; however, the participation of various oell types, as well as the occurrenoe of starch grains are altered. The presenoe of 2,4-D alone results in an inhibition of starch occurrence, NAA alone causes a stimulation. There is no causal dependence of the occurrence or absence of starch grains on the stimulation of elongation (volume) growth, or, on the contrary, on cell division.
37 citations
TL;DR: It is concluded that the observed ethylene-induced changes in enzyme aotivities bring about in latex vessels a deviation of the glycolysis-fed metabolio flux from synthetic pathways to mitochondrial oxidations and consequently a decrease in the efficiency of sucrose conversion to rubber.
Abstract: The treatment of the bark of regularly tapped trees with 2-ohloroethylphosphonio acid (CEPA) in the long run brings down sucrose level in the latex even when latex production is not increased. The sucrose deficit thus caused persists for a number of months after the treatment probably due to the depletion of carbohydrate reserves by the stimulation. The loss of carbohydrates not related to an increase of rubber produotion grows as the concentrations of applied CEPA are raised.
31 citations
TL;DR: The germinating capacity of pollen in synthetic media was low; it was confirmed that it might be stimulated by supplementing agar with egg yolk and application of pollen onto styles overhanging from the culture medium of excised ovaries was examined.
Abstract: Suitable conditions for the fertilizationin vitro in maize have been studied. The germinating capacity of pollen in synthetic media was low; it was confirmed that it might be stimulated by supplementing agar with egg yolk. Application of pollen onto styles overhanging from the culture medium of excised ovaries was examined. After 5 days the styles could be cut off the ovaries, for the pollen tubes had already penetrated the embryo sacs. However, better results were obtained when cultivating ovaries along with segments of the maize cob. Solid media were more suitable for the development of kernels. Some of them germinatedin situ and gave rise to normal plants. From nucellar meristems of young kernels a callus could be derived which, on further cultivation, became green and regenerated shoots and roots. The cells of meristems exhibited a varying number of chromosomes.
23 citations
TL;DR: In this article, the transpiration flow rate and the temperature and relative humidity of the air and the vapour pressure deficit measured at the same time in their diurnal course, as well as at the single diurnal terms during the whole time at which measurements were carried out were determined by correlation analysis.
Abstract: The course of the transpiration flow rate (Qw), of transpiration flow acceleration (Qw/dt) and of the integrated transpiration flow was determined during an average summer day by repeated measurements according to the method of heat balance and the free water capacity of the tree trunk was estimated. The relations between the transpiration flow rate and the temperature and relative humidity of the air and the vapour pressure deficit measured at the same time in their diurnal course, as well as at the single diurnal terms during the whole time at which measurements were carried out were determined by correlation analysis. The problems linked with the effect of various meteorological conditions during different times of the day, of rain showers, solar radiation and soil water content are discussed. The possibilities of explaining the midday depression of transpiration on the basis of repeated measurements of the transpiration flow rate are evaluated.
18 citations
Abstract: Biologioal activities of humic acid (Na salt), hymatomelanic acid (Na salt), lignofulvic acid and of fulvic acids isolated from peat were studied by means of the auxin-, gibberellin-, and cytokinin- bioassays. All the four tested fractions showed higher or lower stimulating activity in these bioassays. However, the stimulating effect is considerably lower and cannot be interpreted as phytohormone activity. Some fractions in some concentrations also showed inhibitory effects. The manner of biological action of the studied fractions might bo the result of interaction of their respective components.
17 citations
TL;DR: Following a 24-h exposure to a solution of polyethylene glycol 4 000 of a —12.66 bar osmotic potential the roots of maize ceased growing; however, a 48-h treatment brought about irreversible changes.
Abstract: Following a 24-h exposure to a solution of polyethylene glycol 4 000 of a —12.66 bar osmotic potential the roots of maize ceased growing. The inhibition of growth was conditioned by the inhibition of cell elongation and division. The elongation of cells was substituted by their radial enlargement which took place both in the peripheral and central root parts. The cells either did not divide at all, or sporadic mitoses still occurred in the roots. The meristematic cells treated were highly vacuolized, chromatin condensation being observed in their nuclei. In contrast to growth processes, differentiation was stimulated: the formation of the secondary wall in protoxylem elements occurred at a shorter distance,i.e. 1 500–2 400 µm from the apex, in comparison with 4000–5 000 µm in the control, this evidently being caused not only by the inhibition of growth, but also by the capacity of cells to differentiate more rapidly. The changes induced by a 24-h exposure to water stress were of a reversible nature; however, a 48-h treatment brought about irreversible changes.
14 citations
TL;DR: Methyl methanesulphonate induced a high frequency of chromosome aberrations observed at anaphase and metaphase and depressed the mitotic division in the root-tips of excised embryos.
Abstract: Excised barley embryos were treated with methyl methanesulphonate and cultivatedin vitro in water or in a nutrient medium. The alkylating compound induced a high frequency of chromosome aberrations observed at anaphase and metaphase and depressed the mitotic division in the root-tips of excised embryos.
11 citations
TL;DR: The change in the growth correlations following photoperiodic induction together with the total activation of RNA synthesis are considered to represent one of the first events of the transition to the reproductive state.
Abstract: Uridine-3H incorporation and RNA concentration were investigated in different parts of the shoot apical meristem ofChenopodium rubrum using autoradiography and cytophotometry. A single inductive cycle was sufficient to bring about postinductive first events in the shoot apex but not for complete flower differentiation. The initial activation of RNA synthesis manifested itself in all zones of the apex. The first increase was more conspicuous in the peripheral than in the central zone. The indications of the first events in the apices after a single inductive cycle disappear prior to morphological reversal to the vegetative state. Induction by three short days led to rapid flower differentiation. The increase in RNA synthesis and concentration was most conspicuous in the central zone in this case. The ratio of RNA synthesis and content between bud and leaf primordia (B/L) also change in relation to photoperiodic induction. In vegetative plants the B/L ratio was low while after induction it increased.
11 citations
TL;DR: In contrast to their soil counterparts, algal fulvic acids were more inhibitory than the corresponding humic acids in inactivating the enzyme as discussed by the authors, and Fulvic acids from Fucus vesiculosus were more efficient than their corresponding Laminaria digitata acids.
Abstract: In contrast to their soil counterparts, algal fulvic acids were more inhibitory than the corresponding humic acids. Fulvic and humic acids fromFucus vesiculosus were more efficient than the correspondingLaminaria digitata acids in inactivating the enzyme.Laminaria humic acids, which have no phenolic hydroxyls, showed a concentration dependent inhibition hardly in accordance with the presumed role played by these groups in the activity of oxidases.
TL;DR: The hydration level of leaves was characterized by their water potential (ψw), osmotic potential, pressure potential ψp and water saturation deficit(ΔWsat) as mentioned in this paper.
Abstract: Water stress in the leaves was induced by gradual decreasing of substrate moisture in five-day cyclesThe hydration level of the leaves was characterized by their water potential (ψw), osmotic potential (ψs), pressure potential ψp and water saturation deficit(ΔWsat)The activities of Photosystems 1 and 2 were determined polarographically with Pt/Ag(AgOH) electrode as changes in oxygen concentration in chloroplast suspensions The shape of light curves of Hill reaction was not influenced by leaf (ψw), hence both quantum efficiency and dark phase of this process were affected in a similar manner by water deficit The activities of both photosystems measured at saturating photon flux density declined with the lowering of leaf (ψw) (in the range from -5 to -14 x 105 Pa) and the decrease in activity of Photosystem 2 was more rapid than that of Photosystem 1 The ratio of activities of Photosystems 1 and 2 was mildly enhanced by a lowering of (ψw), but it decreased with increasing age The lowering of ψwinduced lowering in the chlorophyll a/b ratio thus concealing the usual ontogenetic course of this ratio
TL;DR: In only one cultivar out of 1200 investigated cultivars ofPhaseolus vulgaris L. vulgaris could the authors find an extreme change in the pattern of reserve proteins on the cathodic side: one of the proteins, called protein I, is completely absent in the cultivar ‘Krupnaya sakharnaya’ and is replaced on the same site by another protein,i.e. a protein completely different in its immunochemical specificity.
Abstract: In only one cultivar out of 1200 investigated cultivars ofPhaseolus vulgaris L. could we find an extreme change in the pattern of reserve proteins on the cathodic side: one of the proteins, called protein I, is completely absent in the cultivar ‘Krupnaya sakharnaya’ and is replaced on the same site by another protein,i.e. a protein completely different in its immunochemical specificity. The case is of interest from both the phylogenetic and systematic viewpoints and deserves further attention.
TL;DR: Alfalfa mosaic virus (AMV) and tomato bushy stunt virus (TBSV) were serologically identified in the leaves of some of 8 samples of hop plants and of 17 bushes of grapevine, showing a complex of symptoms described in this paper.
Abstract: In agreement with the results of biological tests with transmission to herbaoeous indicators and on orientation electron microscopic investigation, alfalfa mosaic virus (AMV) and tomato bushy stunt virus (TBSV) were serologically identified in the leaves of some of 8 samples of hop plants and of 17 bushes of grapevine, showing a complex of symptoms described in this paper. The latter reacted in double gel diffusion tests toPetunia strain but not to artichoke strain. The identification of these two viruses in grapevine is the first finding in Czechoslovakia, whereas in hop it is probably the first finding anywhere.
TL;DR: The action of exogenously applied hormones in the induction of morphogenesis in Limnophila chinensis (Osb.) Merr.
Abstract: The action of exogenously applied hormones in the induction of morphogenesis inLimnophila chinensis (Osb.) Merr. tissue culture has been demonstrated. Stem expiants were grown on Murashige and Skoog’s medium containing various levels of kinetin, gibberellic acid and indole-3-acetic acid. Formation of roots, shoots (normal or abnormal), plantlets and friable, hard or nodulated calluses depended largely on the hormone levels used. The formation of normal shoots and roots were stimulated by treatment with kinetin. GA3 treatment stimulated the bud differentiation but inhibited the root initiation. A combination of kinetin and GA3 gave variable results.
TL;DR: The main enzymatic oxidation products of IAA have been tested for biological activity, using as bioassay the straight-growth test of Avena coleoptile, and results accord with the evidence that IAA is the true hormone of plant growth.
Abstract: The main enzymatic oxidation products of IAA have been tested for biological activity, using as bioassay the straight-growth test ofAvena coleoptile. After being purified by rechromatography, none of these products (including methyleneoxindole) exhibited biological activity within the wide range of concentrations employed; consequently, the results accord with the evidence that IAA is the true hormone of plant growth.
TL;DR: The germination of the pollen from11 individuals of six wildRosa species was studied, and the presence of calcium resulted in increased pollen germination, longer pollen tubes, and in a decrease of the requirement of sucrose concentration in cultivation media.
Abstract: The germination of the pollen from11 individuals of six wildRosa species was studied The presence of calcium resulted in increased pollen germination, longer pollen tubes, and in a decrease of the requirement of sucrose concentration in cultivation media Pollen germination in the medium with Ca reached the values of pollen viability estimated by tetrazolium test in all cases except with roses with balanced heterogamy, of the sectionCaninae The stimulating effect of calcium was generally most pronounced in the pollen from roses of hybrid nature, such asR jundzillii, R canina, and especially in the case of the calciphilous speciesR eglanteria
TL;DR: Zn2+ ions slightly enhance at low concentrations the activity of tryptophan synthase obtained from the shoots of 14-day-old pea seedlings (Pisum sativum L.) and thus they are participating in the in vivo experiments.
Abstract: Zn2+ ions slightly enhance at low concentrations (0.01 μg ml-1) the activity of tryptophan synthase obtained from the shoots of 14-day-old pea seedlings (Pisum sativum L.). On the contrary, high concentrations of Zn2+ (10 μg ml-l) exert an inhibitory effect. The direct Zn2+ activation of tryptophan synthase, establishedin vitro with a partially purified enzyme preparation, is relatively low and obviously is not decisive from the point of view of tryptophan biosynthesis of the enzyme and thus they are participating in thein vivo experiments.
TL;DR: Isolated protoplasts were prepared from sugar beet leaves by means of the action of a non-specific enzyme xylonase; homologous fusions and total yield were examined as mentioned in this paper.
Abstract: Isolated protoplasts were prepared from sugar beet leaves by means of the action of a non-specific enzyme xylonase; homologous fusions and total yield were examined.
TL;DR: Gamma radiation in doses significantly stimulated seed germination, seedling height, and length of primary leaves of French bean cv.
Abstract: Gamma radiation in doses 0.13 to 0.77 C kg-1 (0.5 to 3.0 kR) significantly (P ≥ 0.01) stimulated seed germination, seedling height, and length of primary leaves of French bean cv. ‘Blue Lake’; these doses did not affect chlorophyll content per leaf area unit. Doses of 1.16 to 1.93 C kg-1 (4.5 to 7.5 kR) induced inhibition of the four parameters studied.
TL;DR: P-coumaric acid (HCA), 2,4-dichlorophenol (DCP) and resorcionol acted as cofactors for IAA-oxidase isolated from young wheat plants.
Abstract: P-coumaric acid (HCA), 2,4-dichlorophenol (DCP) and resorcionol acted as cofactors for IAA-oxidase isolated from young wheat plants. Ferulic acid (FA) and 3,4-dihydroxybenzoic acid (DHBA) induced a lag phase prior to IAA oxidation. HCA, FA (0.2-1 mg ml-1) and DCP (0.03-1 mg ml-1) strongly inhibited wheat coleoptile section growth. DHBA (0.01-1 mg ml-1) slightly stimulated it and resorcinol was without effect. HCA inhibited IAA-induced growth of coleoptile sections and FA stimulated it at low IAA levels and inhibited it at higher ones. DHBA, DCP and resorcinol did not affect IAA-induced growth of coleoptile sections.
TL;DR: From the beginning of the vegetation till the end of flowering these most efficient plants showed the lowest permitivity dispersion and the highest dispersion after the flowering time, and the dispersion has increased towards theend of vegetation.
Abstract: When examining plants of white mustard (Sinapis alba L.), a significant relationship between the size of the roots and the yield was found, both in a pot experiment and in a field one. The yield was influenced by the size of the root system during and after flowering time. Especially the number of seeds has increased, and the average weight of seeds showed the same tendencies after the flowering time. The productivity of plants with an above-average yield was increasing more quickly than the size of their root system. From the beginning of the vegetation till the end of flowering these most efficient plants showed the lowest permitivity dispersion and the highest dispersion after the flowering time. The dispersion has increased towards the end of vegetation.
TL;DR: In this paper, the effects of acetylcholine (Ach) on growth, the total peroxidase activity and the isoperoxidases spectrum of the roots ofLens culinaris were compared with actual and earlier results obtained with an auxin (IAA) treatment.
Abstract: The effects of acetylcholine (Ach) on growth, the total peroxidase activity and the isoperoxidase spectrum of the roots ofLens culinaris were studied and compared with actual and earlier results obtained with an auxin (IAA) treatment. The general growth and peroxidase activity patterns of Ach treated roots and IAA treated ones showed many important similarities.
TL;DR: It is postulated that phloridzin accumulation and its glucosidase activity are indirectly related to the after-ripening process and directly to the germination of the embryos.
Abstract: Phloridzin level and phloridzin β-glucosidase activity were estimated during apple seed cold stratification and during the culture of apple embryos isolated from seeds after different times of stratification. Both these factors were found to increase parallel to the progress of stratification as well as to the increasing ability of seeds/embryos to germinate. However, in the seed coats phloridzin dissappears during the progress of stratification despite the increasing β-glucosidase activity. Phloridzin formation in the embryos is postulated to be under light and gibberellin control, when isolated embryos germinate, and under temperature and gibberellin influence during the cold stratification of the seeds. The same factors control β-glucosidase activity development, which is also stimulated by the substrate itself. It is postulated that phloridzin accumulation and its glucosidase activity are indirectly related to the after-ripening process and directly to the germination of the embryos.
TL;DR: A propagation method for somereesia cultivars usingin vitro cultures is described and Bud and root formation was evoked in callus tissue culture on a modified Murashige and Skoog’s medium.
Abstract: A propagation method for someFreesia cultivars usingin vitro cultures is described. Bud and root formation was evoked in callus tissue culture on a modified Murashige and Skoog’s medium. Reconstituted plants were transferred into soil and cultivated in the glasshouse.
TL;DR: In this paper, it was shown that nyctinastic oscillations of the leaves are controlled by the same mechanism as is the circumnutation of the stem, leading to side-deviations of the growing leaves in the direction of their shorter half axis.
Abstract: A previous report on the mechanism of diurnal oscillations is supplemented here by data concerning causes of irregularities in their oscillation trajectories. Cinematographic records showed that the final trajectory is significantly influenced by the circumnutation oscillations of the stem. Amplitudes of these oscillations which are small(ca 0.7 mm as compared with 5 X larger amplitudes of leaves when measured at the leaf tip) can be enlarged up to 10 times the value at the apical tip of the leaf. These nutations are responsible for side-deviations of space spirals of growing leaves in the direction of their shorter half axis. This explanation is based on the occurrence of side-deviations of leaf trajectories which correlate with the actual position of the nutation phase of the stem. Concurrent frequencies of the two oscillations (= diurnal rhythm) indicate that nyctinastic oscillations of the leaves are controlled by the same mechanism as is the circumnutation of the stem.
TL;DR: The rapid labelling and the polydisperse rather low molecular weight character suggest that the D-RNA is a heterogeneous population of mRNA and the sedimentation profile of TB-RNA was similar to that of D- RNA.
Abstract: The RNA formed in pollen tubes during 4 hours of growthin vitro was resolved by chromatography on methylated albumine on kieselguhr (MAK) into three principal fractions. Acoording to the labelling from uracil-14C about 11% was eluted with tRNA and 5 S RNA (low molecular weight RNA), 76% just after rRNA (D-RNA) and nearly 14% was recovered from the column by SDS at 35 °C (TB-RNA). In the presence of actinomycin D at concentration of 30 μg ml-1 the synthesis of the three classes of RNA was inhibited by 71%, 97% and 70% respectively. On sucrose density gradient the radioactive low molecular weight RNA sedimented at 4 S-5 S which suggests that one or both of these RNA species are synthesized in pollen tubes. The D-RNA eluted from the MAK column is polydisperse in size exhibiting a wide range of sedimentation values up to about 35 S with a large peak at 9 S-10 S and two smaller peaks at 14 S-15 S and at about 23 S. The rapid labelling and the polydisperse rather low molecular weight character suggest that the D-RNA is a heterogeneous population of mRNA. The sedimentation profile of TB-RNA was similar to that of D-RNA. The RNA synthesized in the presence of32PBO3-4 or uracil-14C exhibited no radioactivity peaks corresponding to sedimentation peaks of rRNA.
TL;DR: The results are discussed with respect to the possible ohanges in photoperiodic sensitivity brought about by the rate of initial growth of Chenopodium rubrum seedlings.
Abstract: Flowering ofChenopodium rubrum seedlings fed different sugars at a concentration of 0.6 and 0.4 M, reap, during a single inductive cycle was stimulated or inhibited in dependence on the conditions of germination and initial growth. Plants allowed to germinate at alternating temperatures of 28 °C and 5 °C showed a slower initial growth and their development was stimulated by some sugars as compared to controls induced in the absence of sugars. Plants germinated at alternating temperatures of 32 °C and 5 °C exhibited a rapid initial growth and flowering was inhibited after induction in the presence of sugars. On the other hand, development proceeded more rapidly in control plants induced in the absence of sugars after germination at the higher temperature than after germination at the lower one. The differences between the two variants quoted above could be observed also after induction by two 16 h dark cycles. Glucose and sucrose were most effective in stimulating flowering under appropriate conditions of germination. Fructose was less effective and the action of maltose was very weak. Xylose, ribose and galactose were innocuous, while arabinose, glucoso-6-phosphate and mannitol were toxic to the plants. The sugars inhibited root growth in all cases and led to an increase in starch accumulation in the underground and overground plant organs. At a concentration of 0.6 M they mostly inhibited the length of the cotyledons and, especially, of the first leaf; at a concentration of 0.4 M growth of the overground organs was stimulated. The results are discussed with respect to the possible ohanges in photoperiodic sensitivity brought about by the rate of initial growth.
TL;DR: In this paper, the significance of Ca2+ for the growth of algae, its participation in the process of nitrate and ammonium nitrogen utilization, and the possibility of substituting Sr2+ with it.
Abstract: The paper deals with the problem of the significance of Ca2+ for the growth of algae, its participation in the process of nitrate and ammonium nitrogen utilization, and with the possibility of substituting Sr2+ for it. It was revealed that calcium represents a microbiogenous element for the algae tested, which takes part in the utilization of nitrate nitrogen. It cannot be replaced by strontium especially at a high growth rate of mixotrophically cultivated algae (ina glucose medium).