Showing papers in "Biologia Plantarum in 1986"
48 citations
TL;DR: The results indicate the involved of coarse regulation of the activity of the enzyme by its content without the involvement of fine regulation by the ratio NADPH/NADP+ and RC.
Abstract: The contents of NADP+, NADPH, changes in the activity of glucose-6-phosphate dehydrogenase and some questions relating to its regulation in leaf tissues of tobacco plants infected with PVY were studied. The content of NADP+ and the total sum of pyridine nucleotides decreased after inoculation to 15 % and 30 %, respectively, whereas the content of NADPH increased up to the threefold control value. The contents of NADP+, NADPH and Σ(NADPH + NADP+) linearly correlated with the reproduction curve of PVY. The value of the reduction charge RC and the value of the ratio NADPH/NADP+ sharply increased after inoculation up to tenfold and eighteenfold values, respectively, of the healthy control.
24 citations
TL;DR: Antagonistic action of phenolic compounds towards ABA, and increasing the action of GA when present together with GA and ABA establishes a dual role to this class of compounds; balancing the effect of both growth promoting and growth inhibiting hormones.
Abstract: Abscisic acid, a potent growth inhibitor inhibits hypocotyl growth ofRaphanus sativus seedlings. Phenolic compounds,viz., trans-cinnamic acid, chlorogenic acid, ferulic acid, salicylic acid, tannic acid and quercetin when applied with ABA, antagonize ABA action and restore normal seedling growth. Gibberellic acid promotes hypocotyl growth and on combined application with ABA, the ratio of their concentrations determines the course of the resultant growth. This interaction can be modulated by phenolic compounds. Phenolic compounds in low concentrations when present together with GA and ABA, favour GA-induced growth by antagonizing the inhibitory influence of ABA. The inhibitory action of abscisic acid on a wide range of growth processes is so far known to be reversed only by growth promoting hormones,viz., IAA, GA and cytokinins. Antagonistic action of phenolic compounds towards ABA, and increasing the action of GA when present together with GA and ABA, establishes a dual role to this class of compounds; balancing the effect of both growth promoting and growth inhibiting hormones.
23 citations
TL;DR: The results stress the importance of photosynthate allocation for the physiology of laticiferous system productivity and indicate the possibilities of improving assimilate economy in rubber trees.
Abstract: Manipulations of production systems in rubber tree which were intended to improve sucrose translocation in tapped bark resulted in an increase of latex sucrose and of latex production and reduced the incidence of nonyielding laticiferous tissue. This was achieved by shortening the tapping cut from full to half spiral, by changing the descending direction into an ascending mode of tapping or by annual change-over of tapping panel allowing for a longer time the regeneration of bark removed above the location of the cut. The increase of latex yield did not result in a significant decrease in the growth of trees over a period of three years. Clonal differences in nonyielding bark appeared to be related to differences in sucrose depletion by tapping. In clone PB 235 which exhibited low latex sucrose, a reduction of tapping frequency resulted in an increase in sucrose level and in a decrease of bark “dryness” tending to an increase in total yield. The tapping manipulations examined did not affect latex flow characteristics such as the plugging index of latex vessels and the bursting index of lutoids. The results stress the importance of photosynthate allocation for the physiology of laticiferous system productivity and indicate the possibilities of improving assimilate economy in rubber trees.
22 citations
TL;DR: Of the various additives employed to counteract the problem of browning and subsequent necrosis, polyvinylpolypyrrolidone (PVPP) was found most effective.
Abstract: The occurrence of browning in protoplast cultures ofCyamopsis tetragonoloba completely inhibited the growth of protoplast derived colonies. Of the various additives employed to counteract the problem of browning and subsequent necrosis, polyvinylpolypyrrolidone (PVPP) was found most effective. Simultaneous addition of polyvinylpyrrolidone (PVP) to the protoplast culture medium accentuated the effect of PVPP and also improved the frequency of protoplast division.
20 citations
TL;DR: It is proposed that MT is a possible source of endogenous auxin in plants and can be hydrolyzed by plant cells with liberation of D-tryptophan, which in turn can be used in IAA synthesis.
Abstract: N-malonyl-D-tryptophan (MT) and D-tryptophan added to the medium instead of auxin stimulated growth of soybean and tomato cell and tissue cultures. Effects of 50–100 μmol 1-1 MT and 100 –300 μmol 1-1 D-tryptophan were equal to the effect of 3–10 μmol 1-1 IAA. Soybean cells grown in the presence of 100 μmol 1-1 MT contained 125–170 ng IAA per 1 g fresh mass (as determined by spectrofluorimetric indole-α-pyrone method), whereas the cells grown in the presence of NAA 10. 7 μmol 1-1 contained 50 –60 ng IAA and the cells grown in the absence of auxin failed to show endogenous IAA. MT as proposed can be hydrolyzed by plant cells with liberation of D-tryptophan, which in turn can be used in IAA synthesis. It is proposed that MT is a possible source of endogenous auxin in plants.
16 citations
TL;DR: Proline accumulation in coleoptiles of wheat seedlings was studied in this article, where the seedlings were incubated in 5 mM citric acid in a pH range from 4.5 to 7.0 and only a slight increase of proline content after incubation in phosphate buffer at pH 7.5.
Abstract: Proline accumulation in coleoptiles of wheat seedlings or in excised coleoptile segments incubated under shaking for a 24 h period was studied. There was no increase of proline content of coleoptiles after incubation of the seedlings in 5 mM citric acid (a relatively strong and slowly penetrating organic acid) in a pH range from 4.5 to 7.0 and only a slight increase of proline content after incubation in phosphate buffer at pH 7.0 to 7.5 duo to the higher osmotic concentration of phosphate buffer in this pH range. Quite different results were obtained with seedlings incubated in 10 mM acetic acid, a weak and easily penetrating organic acid. With increasing proton concentrations, proline accumulation increased. Application of 400 mM mannitol or higher concentrations of IAA (more than 10−5M) additionally increased proline accumulation in the presence of 10 mM acetic acid in the pH range from 6.0 to 7.5 in which acetic acid alone was loss effective. It is suggested that a decrease of cytosolic pH causes stress—induced proline accumulation.
13 citations
TL;DR: Investigation of the effect of phosphorus deficiency on acid phosphatase activity in the apical, middle and basal parts of the root of maize plants found a higher enzymatic activity in all root segments in fraction III than in fraction II.
Abstract: The effect of phosphorus deficiency on acid phosphatase activity in the apical, middle and basal parts of the root of maize plants was followed. The supernatant obtained by centrifuging the homogenate of plant tissue at 1500 ×g was further centrifuged at 18 000 ×g, the sediment being marked as fraction II and the supernatant as fraction III. The results obtained document the fact that acid phosphatase activity of the two fractions of all analyzed root segments was higher in plants cultured in nutrient medium without phosphate than in those containing phosphorus in nutrient medium. In most cases this difference was significant to highly significant. The results of experiments proved unambiguously a higher enzymatic activity in all root segments in fraction III than in fraction II. In fraction III the highest acid phosphatase activity was found in the apical part, in fraction II in the basal part of the root.
11 citations
TL;DR: Petunia hybrida plants inoculated with different Agrobacterium rhizogenes and A. tumefaciens strains developed tumors and developed tumors were further cultivated in vitro and permanent growth of isolated untransformedPetunia roots was not induced by addition of IAA into the medium.
Abstract: Petunia hybrida plants were inoculated with differentAgrobacterium rhizogenes andA. tumefaciens strains and developed tumors were further cultivatedin vitro. Transformed flowering plants differentiated from tumors induced byA. rhizogenes strains 8196 and TRIOL Transformed but non-rooted plants developed also from tumors incited byA. tumefaciens T37. Cultures of roots transformed byA. rhizogenes strain 15834 did not show increased incidence of chromosomal aberrations in anaphases in comparison with untransformecl control. Permanent growth of isolated untransformedPetunia roots was not induced by addition of IAA into the medium.
11 citations
TL;DR: This work has investigated the variation of growth substances when anoxia was imposed to rice seedlings previously grown in air, and observed an increase, in all the organs of a seedling and in particular in the fraction released in the medium, for ABA, PA, PA and DPA quantities.
Abstract: The rice is important in plant science for its ability to germinate and grow with restricted or without oxygen availability. In this work we have investigated the variation of growth substances when anoxia was imposed to rice seedlings previously grown in air. An increase, in all the organs of a seedling and in particular in the fraction released in the medium, was observed for ABA (abscisic acid), PA (phaseic acid) and DPA (dihydrophaseic acid) quantities.Vice versa a reduction of total IAA (indol-3-ylacetic acid) was observed in seedlings. This was accompanied by its accumulation in roots. IAA was poorly released in aerobic conditions and anoxia has not changed this pattern.
11 citations
TL;DR: The basal region of seminal roots thus differs in its ontogenesis from the increase which is formed “de novo” by the action of root meristem upon seed germination.
Abstract: In addition to the primary seminal primordium, the so-called secondary seminal root primordia are also initiated in a barley embryo. The primary root primordium is developmentally most advanced. It is formed by root meristem covered with the root cap, and by a histologically determined region with completed cell division. On germination, the restoration of growth processes begins in this non-meristematic region of root primordium by cell elongation, with the exception of the zone adjacent to the scutellar node, the cells of which do not elongate but continue differentiating. In the root primordia initiated later, the zone with completed cell division is relatively shorter, in the youngest primordia the non-meristematic cells may be lacking. The root meristem is reactivated after the primary root primordium has broken through the sheath-like coleorrhiza and emerges from the caryopsis as the primary root. The character of root meristem indicates a reduced water content at the embryonic development of root primordium. With progressing growth the root apex becomes thinner, the meristematic region becomes longer, and the differences in the extent of cell division between individual cell types increase. — The primary root base is formed of cells pre-existing in the seminal root primordium. Upon desiccation of caryopsis in maturation, and subsequent quiescent period, their development was temporarily broken, proceeding with the onset of germination. The length of this postembryonically non-dividing basal zone is different in individual cell types. The column of central metaxylem characteristic of the smallest number of cell cycles, has, under the given conditions, a mean length of about 22 mm, whereas the pericycle, as the tissue with most prolonged cell division, has a mean length of about 6 mm. In the seminal root primordia initiated later the non-dividing areas are relatively shorter. The basal region of seminal roots thus differs in its ontogenesis from the increase which is formed “de novo” by the action of root meristem upon seed germination.
TL;DR: The red radiation was the most effective to increase the carotenoid biosynthesis, but the green and blue radiations inhibited their production, and neither type of radiation was so efficient in increasing the total carOTenoids content as the full sun radiation.
Abstract: Capsicum annuum L. cv. Ramillete fruits grown in the field were covered 60 d after flowering with “white”, yellow, red and blue cellophane filters. Two other sets were left in full sunlight and under cover, respectively. After 30 d of treatment, during the ripening period, the contents of individual carotenoids were analyzed.
TL;DR: A haemagglutinating material was isolated and purified from the phosphate buffered saline extract of the seeds of the jack fruit using an immobilized N-aeetyl-D-galactosamine column and it was found to be composed of single polypeptide chains and they contained no covalently linked sugars.
Abstract: A haemagglutinating material was isolated and purified from the phosphate buffered saline extract of the seeds of the jack fruit using an immobilized N-aeetyl-D-galactosamine column. This material was composed of two iso-lectins of molecular masses 11 500 and 15 000. The lectins agglutinated native washed red blood cells of the human A, B and 0 groups and sheep, rabbit and mouse erythrocytes. The lectins were found to be composed of single polypeptide chains and they contained no covalently linked sugars. The lower molecular mass material was present in considerably greater quantity than the higher molecular mass component. On isoelectric focussing on PAG the lectins gave a spread of components with calculated pI between 6.0 and 8.3.
TL;DR: The unchanging AEC value in virus-infected tissues simultaneously indicated that no change in the rate of the glycolytic pathway occurred even under “invivo” conditions at the period of the acute stage of infection.
Abstract: The content of ATP, ADP, AMP, Pi, the activity of the enzymes involved in the glycolytic pathway, some problems of their regulation by adenine nucleotides and some basic problems connected with tissue energy balance were studied in tobacco plants infected with the potato virus Y (PVY). The contents of ATP and ΣAdN were increased in virus-infected tissues when compared with healthy tissues and correlated with the PVY reproduction curve. ADP and AMP contents decreased just after the inoculation and increased at the end of the experimental period, Pi content was not influenced by the infection. The activities of the key enzymes of the glycolytic pathway (6-phosphofructokinase, hexosediphosphatase, and pyruvate kinase), determined both in crude homogenates and after partial purification, did not differ during the entire experimental period from the values found in healthy control tissues, similarly as the activities of glucosephosphate isomerase, glyceraldehydephosphate dehydrogenase, phosphoglyceromutase and enolase observed in crude homogenates. The unchanging AEC value in virus-infected tissues simultaneously indicated that no change in the rate of the glycolytic pathway occurred even under “invivo” conditions at the period of the acute stage of infection.
TL;DR: Isolated uninucleate microspores of tomato, Lycopersicon esculentumMill, were cultured in defined, liquid nutritive media and developed to haploid embryoids with or without an attached suspensor or into calli with compactly or loosely arranged cells.
Abstract: Isolated uninucleate microspores of tomato,Lycopersicon esculentumMill, were cultured in defined, liquid nutritive media. The microspores developed to haploid embryoids with or without an attached suspensor or into calli with compactly or loosely arranged cells.
TL;DR: The phenotype appearance ofArabidopsis thaliana hairy roots and crown galls their teratomas and regenerated plants were compared and several differences were found, which correlate with T-DNA differences between Ti and Ri plasmids.
Abstract: The phenotype appearance ofArabidopsis thaliana hairy roots and crown galls their teratomas and regenerated plants were compared. Several differences were found, which correlate with T-DNA differences between Ti and Ri plasmids.
TL;DR: Detailed studies of the roles of endogenous phytohormones in sugar beet root derived cell suspension cultures provide a basis for development of plant growth regulator regimes to optimise sucrose yield from sugar beet.
Abstract: The percentage of sucrose in sugar beet storage root fresh and dry matter is closely related to root structure. It has been suggested that the sucrose content might be increased by using plant growth regulators to modify storage root structure through control of cambial development, cell division and cell expansion. During storage root development correlations were found between the changing phytohormone profiles and the formation of secondary cambia and their subsequent cell division and expansion. Sugar beet root derived cell suspension cultures were used for detailed studies of the roles of endogenous phytohormones. The gibberellin synthesis inhibitor paclobutrazol was tested in cell cultures and whole plants. The observations provide a basis for development of plant growth regulator regimes to optimise sucrose yield from sugar beet.
TL;DR: Research suggests that certain cultivar ofMalus growing at Geneva, New York, USA, begin growth and bloom 2 –3 weeks later than commercial cultivars of apple because these late bloomers bloom late because they have a very high chilling requirement for bud burst.
Abstract: Certain cultivars ofMalus growing at Geneva, New York, USA, begin growth and bloom 2 –3 weeks later than commercial cultivars of apple. Our research suggests that these late bloomers bloom late because they have a very high chilling requirement for bud burst. The chilling requirement interacts with the heat requirement for bud burst in such a way as to result in delayed bud burst and bloom. Abscisic acid (ABA) decreases in the terminal buds of both early and late bloomers during the chilling period, but it decreases more rapidly in the early bloomers. It has not been determined if ABA plays a role in controlling bloom date.
TL;DR: Dry storage of the bulbs in atmospheres containing 5% CO2 reduces the temperature-enhanced flower formation, suggesting a possible effect of endogenous ethylene.
Abstract: Ethylene induces the flower formation and stimulates the flower-bud development of some bulbous plants exposed to the gas when the apex is in the vegetative state. For iris bulbs cv. Ideal maximum responses have been found after exposure to 5 ppm for 8 h; lower concentrations, shorter exposure periods and, depending on seasonal conditions, low temperatures during gas treatment, gave intermediate responses. The effects are opposite to the ethylene induced flower-bud blasting which occurs when bulbous plants are exposed to the gas after completion of the flower formation.
TL;DR: The senescence of detached leaves of the Australian seagrass Zostera muelleri Irmisch ex Aschers was associated with decreased levels of chlorophyll, soluble protein, and alkaline pyrophosphatase and catalase activities, and the cycloheximide sensitivity correlated with low chlorophyLLase activity of the leaf.
Abstract: The senescence of detached leaves of the Australian seagrassZostera muelleri Irmisch ex Aschers was associated with decreased levels of chlorophyll, soluble protein, and alkaline pyrophosphatase and catalase activities. Senescence was faster in artificial seawater than in distilled water. Irradiance has a retarding effect on senescence while cycloheximide did not retard senescence appreciably. The action of cycloheximide was studied usingCyperus rotundus L.,Hydrangea macrophylla (Thunb.) Ser.,Solandra maxima (Sesśe & Moc.) P. S. Green, andDatura suaveolens Humb. & Bonpl., and the cycloheximide sensitivity correlated with low chlorophyllase activity of the leaf.
TL;DR: Gallic and tannic acids reduced the frequency of mutations induced by a direct acting mutagen N-methyl-N’-nitro-N-nitrosoguanidine but had no effect on the mutagenicity of a promutagen dimethylnitrosamine inArabidopsis thaliana.
Abstract: Gallic and tannic acids reduced the frequency of mutations induced by a direct acting mutagen N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) but had no effect on the mutagenicity of a promutagen dimethylnitrosamine inArabidopsis thaliana. Polarographic studies demonstrated a chemical interaction between MNNG and both phenolic acids.
TL;DR: The salt tolerance was studied according to both fresh and dry matter increases of callus cultivated on the media supplemented with various sodium chloride concentrations as well as a high amount of K+, Na+, Ca2+, and Mg2+ ions as found in the East Slovakia salt soil lowland.
Abstract: The salt tolerance was studied according to both fresh and dry matter increases of callus cultivated on the media supplemented with various sodium chloride concentrations as well as a high amount of K+, Na+, Ca2+, and Mg2+ ions as found in the East Slovakia salt soil lowland. The cells tolerate salinity at least up to 85 mM. According to statistical evaluation the salt concentrations used did not inhibit growth rate and development of tissue cultures.
TL;DR: Red light produced a similar effect as white, providing evidence for the effective wavelength of the photo-inhibition of soybean embryos, and it is suggested that possibly light may act through phytochrome by the high irradiance system.
Abstract: The presence of the seed coat delays the early stages of germination of soybean embryos. This retardation seems to be due to the seed coat acting as a mechanical barrier to seedling. Although entire soybean seeds are insensitive to light, removal of the seed coat induces a light requiring condition. The early germination of naked seeds or isolated embryonic axes is enhanced by darkness. Red light produced a similar effect as white, providing evidence for the effective wavelength of the photo-inhibition. Far-red light acted similarly to darkness in promoting the early germination of the embryos. It is suggested that possibly light may act through phytochrome by the high irradiance system.
TL;DR: It is suggested that phosphate is an inhibitor of ethylene biosynthesis in sufficiently mature tomato and apple fruits in which the rise of Ethylene production is already very rapid.
Abstract: Tomato fruits on stems immersed in phosphate solution 0.2 M K2HPO4 produced less ethylene than control fruits on stems immersed in water. Phosphate mediated inhibition of ethylene production was found to be the highest in fruits in the pink stage of maturity, which produced ethylene at the highest rate. Phosphate also inhibited ethylene production in slices prepared from maturing fruits, both apple and tomato. We suggest that phosphate is an inhibitor of ethylene biosynthesis in sufficiently mature tomato and apple fruits in which the rise of ethylene production is already very rapid.
TL;DR: N-deprivation induced higher changes in activity of the two enzymes in mesophyll protoplasts than in bundle sheath strands and ATP-sulphurylase activity was more sensitive than O-acetylserine sulphydrylaseActivity to N-deficiency both in whole leaf extracts and in isolated leaf cells.
Abstract: In maize leaves nitrogen (N)-deprivation induced a significant decline of chlorophyl and total N contents. On the contrary, sulphur (S) content increased with N-deprivation. The activities of ATP-sulphurylase and O-acetylserine sulphydrylase also decreased with N-deprivation, but ATP-sulphurylase activity was more sensitive than O-acetylserine sulphydrylase activity to N-deficiency both in whole leaf extracts and in isolated leaf cells. Finally, N-deprivation induced higher changes in activity of the two enzymes in mesophyll protoplasts than in bundle sheath strands.
TL;DR: The results indicated that the parallel-resistance equation, used to combine resistances on the two surfaces of a leaf, was not strictly valid when applied to the maize leaves, as the law assumes equal potentials on theTwo surfaces.
Abstract: The objective of this study was to determine if the two surfaces of a leaf had different, or the same, water potentials. Maize (Zea mays L. cv. Cargill 805) was the test plant. During an 11 day period, the water potentials of the upper and lower surfaces of the maize leaves were measured daily with anin situ thermocouple psychrometer under growth-room conditions. Plants were grown in pots with a well-watered, commercial greenhouse soil. Stomatal resistance also was measured. The water potential of the upper surface was less negative (more wet) than that of the lower surface. The overall average of the water potential of the upper and lower surfaces was −1.48 and −2.07 MPa, respectively. The stomatal resistance of the upper surface was greater than that of the lower surface. The average stomatal resistance during the experiment was 780 and 600 s m−1 for the upper and lower surfaces, respectively. Since the upper and lower surfaces were not at the same water potential, the results indicated that the parallel-resistance equation, used to combine resistances on the two surfaces of a leaf, was not strictly valid when applied to the maize leaves, as the law assumes equal potentials on the two surfaces.
TL;DR: In young needles of the Douglas-fir GA9 has been shown by GC and HPLC to be the main gibberellin and minor compounds GA7, GA3 and GA8 have been tentatively identified by HPLC.
Abstract: In young needles of the Douglas-fir (Pseudotsuga menziesii) GA9 has been shown by GC and HPLC to be the main gibberellin. As minor compounds GA7, GA3 and GA8 have been tentatively identified by HPLC. In addition to the free gibberellins small amounts of GA9 glucosyl ester and a not yet identified ester of GA20 have been isolated. From the group of endogenous inhibitors ABA has been identified by GC-MS and ABA glucosyl ester by HPLC. After enzymatic hydrolysis of the ester, ABA and glucose have been quantified by GC and GOD-POD reaction giving the ratio 1:1. Another plant growth inhibitor has been identified as the methyl ester of jasmonic acid.
TL;DR: PheP severely inhibits anthocyanin synthesis in seedlings of red cabbage, with moderate inhibition of PAL activityin vivo and markedly stimulates L-phenylalanine ammonia-lyase activity in vivo and inhibits it in vitro.
Abstract: 1-Amino-2-phenylethylphosphonie acid (PheP) retards growth inSpirodela oligor-rhiza causing morphological malformations, inhibits chlorophyll synthesis in progeny fronds, and markedly stimulates L-phenylalanine ammonia-lyase (PAL) activityin vivo and inhibits itin vitro; in prolonged experiments ribonuclease activity is stimulated. PheP severely inhibits anthocyanin synthesis in seedlings of red cabbage, with moderate inhibition of PAL activityin vivo; chlorophyll synthesis and growth of the seedlings are little affected.