Showing papers in "Biologia Plantarum in 1980"
244 citations
TL;DR: Sap flow rate (Qw) and leaf water potential (Ψw.leaf) in adult specimens of birch (Betula) and oak (Quercus) were measured under contrasting soil moisture conditions as discussed by the authors.
Abstract: Sap flow rate (Qw) and leaf water potential (Ψw.leaf) in adult specimens of birch (Betula) and oak (Quercus) were measured under contrasting soil moisture conditions (Ψw.sofl). With sufficient soil moisture Qw reached about 250 cm3h−1 calculated per unit tree-trunk segment as given by 1 cm length of its circumference. In soil water-stress conditions (when Ψw.leaf = = −15 × 105Pa), birch stopped transpiration and wilted. Oak transpired even when Ψw.leaf fell below −20 × 105Pa. The relation between Qw and Ψw.leaf was always linear and with various Ψw.soil differed in the slopes of regression lines only. Hydraulic conductance (Kwcu) with nonlimiting moisture conditions reached about 6 × 10−9m3 10−5Pa−1s−1 and “conductivity” (“kwa”) when calculated per leaf area unit reached about 23 m 10−5Pa−1s−1. Kwcu and “kwa” were of about one half to nine times greater in birch than in oak. On the basis of relations between Ψw.soil at various depths, Ψw.leaf and Qw (resp. Kw) it is possible to assess the maximal rooting depth and the effective depth where the maximum of absorption of roots occurs. It is to be seen that the root system macrostructure substantially participates in the drought avoidance of adult trees in a forest stand.
59 citations
TL;DR: Studies on seeds of 40 arid zone plant species have revealed that seeds exhibit differential specificity in water inhibition percentage, and those seeds which imbibed showed a very high percentage of water uptake.
Abstract: Studies on seeds of 40 arid zone plant species have revealed that seeds exhibit differential specificity in water inhibition percentage. Most of these seeds show very poor imbibition capacity and that takes place within the first three hours, after which this uptake becomes very slow. This low hydrature and quick water uptake wherever it takes place is correlated with the erratic rainfall in the Indian arid zone. Most of the leguminous seeds are impermeable to water because of hard seed coatedness. However, those seeds which imbibed showed a very high percentage of water uptake.
52 citations
TL;DR: The hypothesis that especially blue light promotes amaranthin accumulation in Amaranthus seedlingsvia the increase of cytokinin content of tissues is supported.
Abstract: The influence of light, particularly blue and red light, on the cytokinin content of seedlings ofAmaranthus caudatus was studied. Cytokinin content was determined by two different bio-assays (amaranthin accumulation byAmaranthus seedlings and mtrate-reductase activity ofAgrostemma embryos). In both bio-assays similar results were obtained. Oytokinin content is increased, especially by blue light. It is suggested that especially blue light promotes amaranthin accumulation inAmaranthus seedlingsvia the increase of cytokinin content of tissues. The results support our hypothesis on cytokinin action.
34 citations
TL;DR: The relatively low and moderatesalinization levels resulted in a promotion rather than inhibition of the dry weight and in the content of most of the investigated elements in the different organs of the test plants, but with the rise of salinization level from 60 to 100 meq l−1, thedry weight and the contentof these nutrient elements were mostly reduced.
Abstract: Using water culture technique, some experiments have been performed to investigate the effect of 60 days salinization treatments (0.0–100 meq 1−1 NaCl) on dry weight and on the content of some nutrient elements (Na, K, Ca, Mg, P, N) in castor bean, sunflower and flax plants. In general the content of sodium increased progressively with the rise of salinity level. The relatively low and moderate salinization levels (20 and 40 meq I−1 NaCl) resulted in a promotion rather than inhibition of the dry weight and in the content of most of the investigated elements in the different organs of the test plants. However with the rise of salinization level from 60 to 100 meq l−1, the dry weight and the content of these nutrient elements were mostly reduced.
19 citations
TL;DR: Differential changes in root and shoot carbohydrates as affected by increasing levels of stress were noticed in drought resistant and susceptible cultivars ofea mays L. May L. were studied under imposed water stress in water culture experiments.
Abstract: Carbohydrate changea in drought resistant and susceptible cultivars ofZea mays L. were studied at two different stages under imposed water stress in water culture experiments. The gradual decline in total carbohydrates with increasing stress levels was observed. At the 1st leaf stage starch content of the resistant cv. Agati-76 was lower than that of susceptible cv. Vijay but the reducing and non-reducing sugar content was much higher. At the 3rd leaf stage starch content was similar in two cultivars but sugar content was higher in the resistant cv. Agati-76. Differential changes in root and shoot carbohydrates as affected by increasing levels of stress were noticed. Carbohydrate changes have been discussed in relation to drought resistance.
18 citations
TL;DR: Extracts from the roots of Boerhaavia diffusa L., stems of Cuscuta reflexa Roxb.
Abstract: Extracts from the roots ofBoerhaavia diffusa L., stems ofCuscuta reflexa Roxb. or leaves ofEuphorbia hirta L. have shown a potential protective effect on the infection of potato virus X, in hypersensitive and systemic hosts. The inhibition by these extracts was systemic and sensitive to actinomycin D.
16 citations
TL;DR: It is demonstrated that the early events of flower bud differentiation are accompanied by stimulation of leaf growth, which means that growth pattern characteristic for induced plants can be evoked in purely vegetative ones.
Abstract: The growth changes of cotyledons, leaves, hypocotyls and roots due to photoperiodic induction in short day plantChenopodium rubrum were investigated in relation to flowering. Six-day old plants were induced by photoperiods with a different number of dark hours. We found that the degree of inhibition which occurred during induction in the growth of leaves, cotyledons and roots similarly as the stimulation of hypocotyl is proportional to the length of dark period. The photoperiods with 12, 16 and 20 dark hours bring about marked inhibition of growth and at the same time induce flowering in terminal and axillary meristems. The inhibitory effect of critical period for flowering,i.e. 8 dark hours, is not apparent in all criteria used and even the flower differentiation is retarded. The photoperiods of 4 and 6 dark hours did not affect growth and were ineffective in inducing flowering even if their number has been increased. The experiments with inductive photoperiod interrupted by light break have clearly shown that growth pattern characteristic for induced plants can be evoked in purely vegetative ones. Such statement did not exclude the possible importance of growth inhibition as a modifying factor of flower differentiation. We demonstrated that the early events of flower bud differentiation are accompanied by stimulation of leaf growth. The evaluation of growth and development of axillary buds at different nodes of insertion enabled us to quantify the photoperiodic effect and to detect the effects due to differences in dark period length not exceeding 2 hours.
16 citations
TL;DR: It was found that exogenously applied cytokinins, in some concentration ranges, markedly increased the number of adventitious branches formed on the cut surface of the thallus fragments.
Abstract: Cytokinin activity was demonstrated in the Baltic sea waters. This activity was always higher in the near-bottom water, taken from theFucus vesiculosuszone, than in the superficial zone. A cytokinin-like substance showing properties typical of 6-(3-methyl-2-butenylamino)purine (2iP) was also present in extracts from the thallus ofFucus. It was found that exogenously applied cytokinins, in some concentration ranges, markedly increased the number of adventitious branches formed on the cut surface of the thallus fragments. The growth responses of the investigated plant tissues to the different cytokinins varied according to season and kind of cytokinin applied. The possibility of exudation of some cytokinin like substances by the algal cells into the surrounding waters was considered.
15 citations
TL;DR: It is suggested that boron supports the incorporation of proteins transported to the growing tip into the pollen tube wall structures and the loss of proteins into the medium is considerably reduced by oalcium and also at the optimal borons concentration and in the presence of K+ and Mg2+ ions.
Abstract: In the absence of cations, the release of proteins from pollen tubes ofNicotiana tabacum in culture is greatly dependent on boron concentration and inversely related to growth stimulation. The minimum of proteins in the medium occurs at 100 mg 1− of boric acid, which is the optimum concentration for growth. The shift of boron level to this optimum further increases the proportion of proteins bound to the insoluble pollen tube fraction; on the other hand the amount of soluble proteins is not affected inside pollen tubes, but greatly decreased in the medium.
14 citations
TL;DR: Increased relative rate of growth of roots and cotyledons was recorded in plants transferred after SD treatment to continuous illumination, however, this rise possesses only transitional character and the relative growth rate of treated plants equals that of control ones afterwards.
Abstract: The relationship between photoperiodically changed growth of leaves, cotyledons, hypocotyl, roots and flowering has been investigated inChenopodium rubrum. It was found that all the growth characteristics recorded in leaves and cotyledons,i.e. length, area, dry weight and chlorophyll content, were inhibited during three inductive photoperiods (16 h darkness, 8 h light-SD) as compared with control plants grown under continuous illumination. Similarly, the cessation of root elongation and a decrease in root dry weight were observed. On the contrary, the elongation and dry weight of hypocotyl are stimulated by SD. The degree of the effect exerted by SD on the growth of different organs depends both on actual growth stage and the number of SD photoperiods. Increased relative rate of growth of roots and cotyledons was recorded in plants transferred after SD treatment to continuous illumination. However, this rise possesses only transitional character and the relative growth rate of treated plants equals that of control ones afterwards. The above growth changes are discussed as a possible modifying factor of floral differentiation.
TL;DR: Ten taxa of the genusPisum were examined by disc electrophoresis in gels according to Davis and to Reisfeldet al. (1980) and results show that Pisum abyssinicum and especially fulvum have biochemically a relatively isolated position.
Abstract: Ten taxa of the genusPisum were examined by disc electrophoresis in gels according to Davis and to Reisfeldet al. For evaluation of band patterns the Jaccard Index was applied. The results in both types of gels show thatPisum abyssinicum and especiallyP. fulvum have biochemically a relatively isolated position.Pisum elatius and its subspeciescaspicum andpalestinicum form a subgroup withP. cinereum;P. sativum var.zeylanicum and cv. Jupiter form another subgroup withP. syriacum. Our results are in good agreement with the results of Przybylskaet al. (with the exception ofP. cinereum) and also with immunoelectrophoretic analyses performed by Turkovaet al. (1980), with the same exception.
TL;DR: The number of secretory canals in the basal and middle anthodial parts increased during the beginning of flowering and the full flowering, and the proportion of the individual sesquiterpenes in the essential oil underwent changes mostly during the starting and termination of flowering.
Abstract: A study was made of the changes in the content of essential oil and its components (farnesene, (-)-α-bisabolol, (-)-α-bisabololoxide A, (-)-α-bisabololoxide B and spathulenol, α-bisabolonoxide A, chamazulene, cis en-in-dicycloether) and of the number of secretory canals in the receptacles during the beginning of flowering, full flowering and the termination of flowering of camomile anthodia. The total content of the essential oil was highest during the beginning of flowering and lowest during its termination. The proportion of the individual sesquiterpenes in the essential oil underwent changes mostly during the beginning and termination of flowering. The number of secretory canals in the basal and middle anthodial parts increased during the beginning of flowering and the full flowering.
TL;DR: The contribution deals with the distribution of β-glucuronidase in the germinating pollen grains of Portulaca grandiflora and the functions of the enzyme in the metabolism of germinated pollen grains are discussed.
Abstract: The contribution deals with the distribution of β-glucuronidase in the germinating pollen grains ofPortulaca grandiflora. In non-germinating pollen grains the enzyme is localized in the pollen wall; the cytoplasmic activity is subdued. With the initiation of germination, the activity of enzyme increases and the positive granules are richly packed in the pollen grains and pollen tubes. The stigma hairs also have such an activity. The functions of the enzyme in the metabolism of germinating pollen grains are discussed.
TL;DR: Protoplasts isolated from cell suspension cultures of potato were cultured as far as the level of regeneration of substrains and the effect of especially the hormonal composition of the medium on different phases of the regeneration of cell colonies was evaluated.
Abstract: Protoplasts isolated from cell suspension cultures of potato were cultured as far as the level of regeneration of substrains. The influence of various factors (age of the cell culture, mode of precultivation, composition of the enzymatic mixture, incubation period) on the efficiency of isolation as well as the viability of protoplasts, has been studied. Various cultivation procedures have been screened and the effect of especially the hormonal composition of the medium on different phases of the regeneration of cell colonies (regeneration of the cell wall, growth and elongation, cell division) evaluated.
TL;DR: In this article, the localization of α- and β-galactosidases in frozen sections of Ca-formol fixed root tips using simultaneous azocoupling reaction was studied.
Abstract: The localization was studied of α- and β-galactosidases in frozen sections of Ca-formol fixed root tips using simultaneous azocoupling reaction. In all species studied (Allium cepa,Cucurbita maxima, Lupinus albus, Pisum sativum, Vicia faba, Zea mays) positive results were obtained, the localization being ubiquitous (according to localization typology given here). InVicia faba andZea mays the isoenzymes of α- and β-galactosidases were revealed by means of acrylamide gel electrophoresis, using authors’ modification of Reisfeld method, in whole root tips, particular growth zones and separately in cortex and central cylinder. No differences were observed comparing stele and cortex. Whereas characteristic isoenzyme patterns were found in individual growth zones in maize, no differences appeared in broad bean. A comparison was made of thein situ localization and of the isoenzyme patterns of α- and β-galactosidases with α- and β-glucosidases. In the case of galactosidases, positive results appear with both α- and β-galactoside. The rising of pH to neutrality leads to considerable decrease in the activity of both galactosidases.
TL;DR: It was observed that humic acids prevent the inhibition of both the hydrolysis and the synthesis of sinapin with malathion even at low concentrations, which shows an acompetitive — noncompetitive character of the inhibition.
Abstract: Humic acids in a concentration of up to 100 μg ml-1 affect the activity of choline esterase of pea only weakly during sinapin (choline ester of sinapic acid) hydrolysis. The inhibition is stronger at higher concentrations. A similar course of inhibition with humic acids was also observed during the synthesis of sinapin catalysed with choline acyltransferase present in the same enzyme extract. The organophosphate malathion is a strong inhibitor of both the hydrolysis and the synthesis of sinapin. Thus, for example, at a 3.5 × 10-5 M concentration it causes 85% inhibition of pea choline esterase. However, in combination with 100 μg of humic acids this inhibition decreases to about 8%. It was observed that humic acids prevent the inhibition of both the hydrolysis and the synthesis of sinapin with malathion even at low concentrations. The interaction of the organophosphate malathion with humic acids seems specific. Humic acids do not affect the inhibition of choline esterase with physostigmine or the inhibition of the hydrolysis and the synthesis of sinapin with chlorocholine chloride, alar and hexamine either. This is also true of the activation of the processes with the K+ ions. Humic acids represent competitive inhibitors of choline esterase. Malathion shows an acompetitive — noncompetitive character of the inhibition. The interaction of humic acids with malathion in the roots of the plants may also be assumed in the soil when malathion is applied as an insecticide.
TL;DR: Transfer experiments between light and shade indicate that Mentha piperita responds very effectively to irradiance also in a late stage of the life cycle with changes of specific leaf area and chlorophyll content.
Abstract: Height growth ofMentha piperita L. is better at 44% than 100% daylight. At 14% daylight, growth is limited, probably by lack of photosynthate, and no flowering occurs. Specific leaf area and protein content increase significantly with the decrease of irradiance. Shade leaves contain more chlorophyll and potassium than sun leaves. Sun leaves show higher levels of calcium because of their more xeromorphic structure. Transfer experiments between light and shade indicate thatM. piperita responds very effectively to irradiance also in a late stage of the life cycle with changes of specific leaf area and chlorophyll content.
TL;DR: During high altitude acclimatization both the number of stomata and their pore width decreased and thickness of leaves also decreased but the effect on the size of epidermal, mesophyll and spongy parenchymatous cells varied from species to species.
Abstract: During high altitude acclimatization both the number of stomata and their pore width decreased. The number of open stomata per unit leaf area in the morning and evening hours was higher as compared to that in plants grown at a lower altitude. Thickness of leaves also decreased at high altitudes but the effect on the size of epidermal, mesophyll and spongy parenchymatous cells varied from species to species. Adaptational significance of these changes are discussed.
TL;DR: The leaves of poplar trees contain antimiorobial agents which differ from the antifungal compounds, which both are different from the antiviral substances.
Abstract: The leaves of poplar trees (genusPopulus) contain antimiorobial agents. These antibiotic properties are markedly influenced by interspecific and intraspecific hybridizations. Fractionation of the weakly active crude extracts results in more active antibacterial fractions. There are indications that the substances which inhibit antimicrobial effects during the testing procedure remain in the methanol fractions. In addition the results show that the antibacterial agents differ from the antifungal compounds, which both are different from the antiviral substances.
TL;DR: It is supposed that this inhibition in the differentiating parts of the shoot apical meristem is related to evocation similarly as the well-known phenomenon of stimulation of cell division in the apical dome.
Abstract: Cell division contributing to longitudinal growth of the shoot apex was investigated inChenopodium rubrum in segments marked by the axils of leaf primordia. Plants treated with two short days (16h of darkness and 8h of light) were compared with two non-induced controls (cultivated in continuous light or treated by alternations of 8 h of darkness and 4 h of light for two days). During the short-day treatments the rate of cell division contributing to the longitudinal growth decreases in all segments of the shoot apex irrespective of whether the darkness was given in inductive or non-inductive photoperiods. The rate of cell division contributing to longitudinal growth increases in the upper internodes of the shoot apex after the termination of the photoperiodic treatment and transfer of the plants to continuous light. However, cell division remains inhibited in the lowest segment of the shoot apex. This inhibition in the differentiating parts of the shoot apical meristem is a direct consequence of photoperiodic induction. It is supposed that this inhibition is related to evocation similarly as the well-known phenomenon of stimulation of cell division in the apical dome.
TL;DR: Twenty-four isolates of turnip mosaic virus (TuMV) from spontaneously infected Sisymbriutn loeselii plants were collected in Bohemian localities and no substantial differences between isolates were observed with infected plants.
Abstract: Twenty-four isolates of turnip mosaic virus (TuMV) from spontaneously infectedSisymbriutn loeselii plants were collected in Bohemian localities. Single lesions on leaves ofNicotiana tabacum cv. Samsun served for inoculating petunia plants used as infection sources for twelve host species. In no case were two identical isolates obtained. 15 isolates could be transmitted toVicia faba, a new TuMV host. Almost all isolates infectedPhaseolus vulgaris cv. Prince locally andTrifolium incarnatum systemically. Seven isolates were transmissible toPisum sativum. No substantial differences between isolates were observed with infectedAn aranthus caudatus, Chenopodium quinoa, Datura innoxia andSinapis alba plants. Several isolates could not infectNicotiana glutinosa at all, other isolates caused in it latent systemic infection and some isolates only local infection contrary to normal local and systemic infections ofN. glutinosa. Attempts to transmit one isolate to cereals failed.
TL;DR: The results seem to demonstrate an interaction between auxin and cytokinin at different ratios throughout the root initiation phase, which suggests that different stages of theRoot initiation phase require different levels of auxIn and cytKinin.
Abstract: Cuttings of pea cv. Alaska and ov. Kelwo were both decapitated and disbudded at different time intervals after cutting. Auxin and cytokinin combined in different ratios were applied to the upper part of the decapitated and disbudded cuttings. The effects of different ratios of auxin and cytokinin were not the same when applied at different developmental stages of the root initiation phase. The results seem to demonstrate an interaction between auxin and cytokinin at different ratios throughout the root initiation phase. The effects of combined application of auxin and cytokinin suggest that different stages of the root initiation phase require different levels of auxin and cytokinin. A higher level of auxin and either lower or equal level of cytokinin may be needed only in the early stages. During the subsequent stages a lower level of auxin in combination with a higher level of cytokinin seems to be more conducive.
TL;DR: It is concluded that the anthocyanin reduction test for GA3 is more sensitive at lower concentrations of GA3 than the amaranthin reduction test.
Abstract: A simple bioassay of gibberellic acid (GA3) based on the GA3-induced reduction of anthocyanin contents in young seedlings of tomato is described and compared with the amaranthin reduction test. It was found that GA3-induced reduction of anthocyanin in tomato seedlings was linear from 10−5 to 10 mg 1−1 GA3 whereas the reduction of amaranthin inAn aranthus caudatus seedlings was linear from 10−3 to 10 mg 1−1 GA3. From these results, it is concluded that the anthocyanin reduction test for GA3 is more sensitive at lower concentrations of GA3 than the amaranthin reduction test.
TL;DR: Changes in glutamine synthetase activity located in the cytosol of root nodules were followed in pea (Pisum sativum L.) plants in relation to their nitrogenase activity but changes during the day and night period could not be unequivocally interpreted in terms of diurnal fluctuation.
Abstract: Changes in glutamine synthetase activity located in the cytosol of root nodules were followed in pea (Pisum sativum L.) plants in relation to their nitrogenase activity. The highest glutamine synthetase activity was found in young nodules (15 days after inoculation) and its changes in 17-to 45-day-old plants showed a positive correlation with nitrogenase activity. In contrast to nitrogenase activity, changes in glutamine synthetase activity during the day and night period could not be unequivocally interpreted in terms of diurnal fluctuation.
TL;DR: The patterns of two biosynthetic activities indicated the presence of a delay in the early phase of imbibition of the aged embryos with respect to viable germs, as well as the dependence of DNA synthesis on protein synthesis.
Abstract: 3H-thymidine incorporation and DNA-polymerase activity during early hours of wheat embryo germination at two viability levels have been studied. The patterns of two biosynthetic activities, as well as the dependence of DNA synthesis on protein synthesis, indicated the presence of a delay in the early phase of imbibition of the aged embryos with respect to viable germs.
TL;DR: The epinastic response of the primary leaf suggests that ethylene participates in the reaction chain of CEPA effect on plant tissues, and may be due to their different effect on cell extension and cell division.
Abstract: Wheat seedlings were cultivated in nutrient solutions containing 10-3 M CCC, 10-3 M CEPA or 5 × 10-4 M CCO and CEPA, respectively. CCC applied alone or mixed with CEPA increased chlorophyll content per unit fresh matter but had no influence on the epinastio response of the primary leaf. In contrast, CEPA had no influence on chlorophyll content but greatly increased the epinastic response. The different response to the application of these substances with regard to chlorophyll content ha been claimed in a previous paper to be due to their different effect on cell extension and cell division. The epinastic response of the primary leaf suggests that ethylene participates in the reaction chain of CEPA effect on plant tissues.
TL;DR: An isolate of wisteria vein mosaic virus (WVMV) obtained from Wisteria sinensis in Prague resembled in its properties WVMV isolates described in Italy and Holland, andNicotiana megalosiphon is reported as a new host of WVR.
Abstract: An isolate of wisteria vein mosaic virus (WVMV) obtained fromWisteria sinensis in Prague resembled in its properties WVMV isolates described in Italy and Holland.Nicotiana megalosiphon is reported as a new host of WVMV. Other known host plants showed reactions similar to those described formerly. The incubation period extended in some hosts up to two or four weeks. Pea plants showed symptoms within five to seven days. Species ofApium, Brassica,Datura and others were not susceptible. TIP of Prague isolate of WVMV was 61 °C, at a dilution 1: 5000 47% of plants were infected, and 48 h > LIV > 28 h. Modal particle length was 743 nm. Massive granular inclusions were seen in pea epidermal cells, usually adhering to nuclei that did not show alterations. No serological relation to turnip mosaic virus could be established.
TL;DR: Twenty three isolates of turnip mosaic virus (TuMV) obtained from spontaneously infected plants of Siaymbrivm loeaeliiJUSL were serologically related, but differed in reactions of eleven host plants.
Abstract: Twenty three isolates of turnip mosaic virus (TuMV) obtained from spontaneously infected plants ofSiaymbrivm loeaelii JUSL. were serologically related, but differed in reactions of eleven host plants. Susceptibility and sensitivity of each host for each TuMV isolate were classified by one of six degrees (0 to 5) respectively. Similarities of isolates (as compared in 253 pairs) were evaluated by means of a computer; for this purpose the source program MINDIF has been elaborated using the universal program language Algol 60. A table of differences between isolates was obtained and distribution of isolate pairs dependent upon the difference values was stated. The fitness of hosts for differentiating TuMV isolates was ascertained quantitatively. No relation of isolate similarity to geographical indices could be established.