Papers by Ivana Macháčková
Biologia plantarum, 1994
A small protein, NP-PI-II, with an N terminus identical to a part of a NJcotiana alata proteinase... more A small protein, NP-PI-II, with an N terminus identical to a part of a NJcotiana alata proteinase inhibitor (PI) II, and an inhibitory activity towards trypsin, has been isolated from flowers of Nicotiana plumbaginifolia. A larger protein was also present from which the smaller protein is likely derived. In N. plumbaginifolia the inhibitor is expressed at very early stages of floral development, this differs from the accumulation pattern during the development of N. tabacum flowers. In mature flowers of both species the inhibitor is constituvely expressed at high level in all floral organs. No inhibitor is present in the vegetative meristems and only a low level of inhibitory activity could be induced by wounding leaves. The inhibitory activity rem~ains high throughout the flower maturation and rapidly declines in the ovary after pollination, in fully developed, green, fruit no inhibitory activity could be detected. In mature N. tabacum flowers trypsin inhibitory activity is detected extraeelhilarly in the stigma exudate. PI activity is not a regular feature in the stigmas of several Solanaceous genera, this could be related to different strategies concerning fruit-function and subsequent dispersal of seeds. In Nicotiana the processing and localization of PI-II appear to be very conserved and PI-II possibly also has a protective function in the flower organs.
Hormonal regulation of plant development in the studies by M. Kh. Chailakhyan In dedication of th... more Hormonal regulation of plant development in the studies by M. Kh. Chailakhyan In dedication of the 100 th anniversary of his birth N. P. Aksenova 3 The plant hormones: From original concepts to a molecular flowering P. J. Davies 9 Three roles for gibberellin in flowering R.. King The role of gibberellin-regulated gene expression during anther and early flower development in tomato
Plant Growth Regulation
The effect of 6-benzylaminopurine (BAP) on floweringand on endogenous levels of isoprenoid cytoki... more The effect of 6-benzylaminopurine (BAP) on floweringand on endogenous levels of isoprenoid cytokinins wasinvestigated in explanted terminal shoots of Chenopodium rubrum cultivated in vitro. Themother plants were grown under continuous light andexplants were cut off when the 6th leaf primordiumoriginated at the shoot apex. The explants wereexposed to one dark period of 13 hours inductive forflowering or to continuous light on medium with orwithout BAP (0.05;0.2;0.4 mg.l-1). Undernon-inductive conditions no flowering was observedeither in the control or after BAP treatment. Afterreceiving one inductive dark period, the controlexplants flowered. However, BAP application either atthe beginning of the inductive dark period and/orduring the following light cultivation inhibitedflowering and stimulated initiation and growth of leafprimordia. In the case of the most efficient BAPconcentration (0.05 mg.l-1) flowering wasinhibited by 80% and the number of leaf primordia wasincreased by 3. Exp...
Zeitschrift für Naturforschung C, 2006
In this paper we report on changes in DNA methylation pattern in rape apices and leaves during tr... more In this paper we report on changes in DNA methylation pattern in rape apices and leaves during transition from vegetative to reproductive stage due to grafting and/or vernalization. Grafted plants of winter rape (Brassica napus L., var. “Górczański”) (stock from vernalized, scion from non-vernalized plants) were used together with vernalized non-grafted plants. In addition, methylation status was determined also in spring rape (var. “Młochowski”) grown under normal and low temperature. The methylation-sensitive amplification polymorphism (MSAP) method with EcoRI/MspI and EcoRII/HpaII restriction enzymes was employed. The majority (ca. 68%) of analyzed loci (566 in winter and 551 in spring rape) were monomorphic, i.e. did not undergo methylation. Both cultivars showed a similar degree of methylation. 188 loci in winter and 176 in spring cultivars expressed changes in the methylation pattern. All differentially amplified fragments resulted from either full methylation of an internal c...
Phytochemistry, 1978
Two pure peroxidase isoenzymes Bl and D4 were isolated from the upper parts of lo-day-old wheat s... more Two pure peroxidase isoenzymes Bl and D4 were isolated from the upper parts of lo-day-old wheat seedlings by means of gel and ion-exchange chromatography. Their MWs were 85000 and 24000 respectively. Bl was unstable and under various conditions it was converted to another isoenzyme, electrophoretically identical with D4. Bl contains about 40 7 of neutral sugars: 17.2 9/o arabinose, 15.3 9/0 galactose, 5 7 glucose and traces of mannose. D4 is free of neutral sugars. None of the isoenzy-mes contained amino sugars. Bt oxidizes ferulic and p-coumaric acids. This oxidation has two pH optima of 4.4 and 5.4-5.6 and is inhibited by high concentrations of substrates, cyanide and azide. Bl oxidizes IAA in the presence of phenolic cofactor and MnZf ions. IAA oxidation has two pH optima of 4.5 and 5.6 and is inhibited by high substrate concentration, cyanide and azide, and by a number of indole derivatives. The main products of IAA oxidation are 3-methyleneoxindole and indole-3-methanol. o-and p&phenols induce a lag period prior to IAA oxidation. Ferulic acid is oxidized during this lag period, probably to a dimer. Bl is able to produce H,O, from oxygen. Mn '+ ions, a phenolic cofactor and an electron donor (IAA or NADH) are needed. Bl oxidizes a-beto-y-methylmercaptobutyric acid to ethylene. D4 has a low peroxidatic activity and is inactive as an IAA oxidase. Thus Bl is probably an active cell wall-bound peroxidase isoenzyme, whereas D4 is its decomposition product.
Plant Science, 2003
2-Aminoindan-2-phosphonic acid (AIP), a potent inhibitor of phenylalanine ammonia-lyase (PAL; EC ... more 2-Aminoindan-2-phosphonic acid (AIP), a potent inhibitor of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), was applied to highly synchronous meristematic cells of Vicia faba roots containing cells in G1/S and G2/M cell cycle checkpoints. The inhibition resulted in a slight decline of the content of hydroxycinnamic derivatives 3.5 h after the AIP application. Flow cytometric analyses and BrdU immunolabelling of replicated cells showed that AIP applied in the G1-phase of the cell cycle delayed the progression through S-phase. The transient delay in DNA replication in treated cells was accompanied by accumulation of free spermidine and perchloric acid (PCA)-soluble spermidine conjugates. The cell cycle checkpoint G2/M appeared to be less sensitive to the inhibitor than G1/S. Mitotic activity of asynchronous root meristems was decreased only after the highest tested AIP concentration was applied (100 mM) for 24 h. Significant increase in free putrescine and perchloric acid soluble-putrescine conjugates in cells after AIPtreatment might represent stress response in cells after AIP application. Increased PA conjugation suggests that it has an important role in the control of free PA contents in cells.
Plant Physiology, 2000
It is now generally accepted that a phosphoinositide cycle is involved in the transduction of a v... more It is now generally accepted that a phosphoinositide cycle is involved in the transduction of a variety of signals in plant cells. In animal cells, the binding of d-myo-inositol 1,4,5-trisphosphate (InsP3) to a receptor located on the endoplasmic reticulum (ER) triggers an efflux of calcium release from the ER. Sites that bind InsP3 with high affinity and specificity have also been described in plant cells, but their precise intracellular locations have not been conclusively identified. In contrast to animal cells, it has been suggested that in plants the vacuole is the major intracellular store of calcium involved in signal induced calcium release. The aim of this work was to determine the intracellular localization of InsP3-binding sites obtained from 3-week-old Chenopodium rubrum leaves. Microsomal membranes were fractionated by sucrose density gradient centrifugation in the presence and absence of Mg2+ and alternatively by free-flow electrophoresis. An ER-enriched fraction was a...
Plant Growth Regulation, 2011
The uptake and metabolism of trans-zeatin and/or dihydrozeatin, in correlation with cytokinin oxi... more The uptake and metabolism of trans-zeatin and/or dihydrozeatin, in correlation with cytokinin oxidase/ dehydrogenase (CKX) and b-glucosidase activity, were studied in leaf segments derived from wild-type (WT) and transgenic (T) tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) during in vitro induction of shoot organogenesis. T explants harbored the maize gene Zm-p60.1 b-glucosidase. Higher levels of shoot regeneration were observed on T explants in the early stages of cultivation. In WT explants, the content of cytokinin (CK)-O-and N-glucosides increased. In T explants, a higher content of Z-9-riboside and Z-9-riboside-5 0-monophosphate and higher CKX activity during the early stage of cultures were found. A positive correlation was obtained for bioactive CK content and the organogenic response in T explants. Our results indicate a connection between the organogenic capacity of tobacco explants, metabolism of endogenous CKs and uptake of exogenous CKs from the cultivation medium.
Plant and Cell Physiology, 2004
The role of ethylene and auxin in stigma-to-ovule signalling was investigated in maize (Zea mays ... more The role of ethylene and auxin in stigma-to-ovule signalling was investigated in maize (Zea mays L.). Maturation of the egg cells in an ear was stimulated before actual fertilization by the application of fresh pollen grains or quartz sand to fully receptive stigmas. Ethylene emission by maize ears increased in response to those treatments. Silks and ovaries were involved in ethylene synthesis after pollen or sand was shed over the silks. The content of ethylene precursor [1-aminocyclopropane-1-carboxylic acid (ACC)] increased in both pistil parts soon after pollination. ACC rise was delayed by 4 h in the ovaries, and by 8 h in the silks after mock-pollination with sand. The auxin level increased rapidly in the silks and ovaries after pollination, and it was very high in the pollinated silks due to the high indole-3acetic acid (IAA) content of pollen grains. IAA rise also appeared in the silks and ovaries after treatment with sand but it was delayed by 8 h. Application of ACC (10 µM) or IAA (6 µM) solutions to non-pollinated silks stimulated maturation of the egg cells. Moreover, the response of the egg cells to pollination was cancelled by L-α-(2-aminoethoxyvinyl)-glycine, α-aminoisobutyric acid or 2,3,5-triiodobenzoic acid applied to the silks before pollination. Thus ethylene synthesis and polar auxin transport in the silks pollinated with fresh pollen were necessary to evoke accelerated differentiation of the egg cells in maize ovules. Differences in pistil responses found between true-and mockpollination suggest that signalling pathways are at least partially different for the reception of pollen grains and sand crystals on maize stigma.
Physiologia Plantarum, 1981
... Is peroxidase imvolyed in ethylene biosynthesis? Ivana Machackova and Zdenek Zmrhal Macha£kov... more ... Is peroxidase imvolyed in ethylene biosynthesis? Ivana Machackova and Zdenek Zmrhal Macha£kova, 1. and Zmrhal, Z. 1981. ... Incubation conditions air N2 air, homo-genate air .air air air air air air air air air air air air air air N2 air N , air air .air air air air Relative C2H4 formation ...
Journal of Plant Physiology, 1991
ABSTRACT Chenopodium rubrum is known to have an endogenous rhythm of flowering with two maxima at... more ABSTRACT Chenopodium rubrum is known to have an endogenous rhythm of flowering with two maxima at about the 12th and 44th h of darkness. Consecutive applications of direct electric current (DC) (6 μA · plant-1, cathode being connected with leaf tips, anode with the roots) within the last 4 h of darkness, i.e. in intervals 0–4, 4–8, .....48–52 h, respectively, after which period the plants were transferred to light, was inhibitory to flowering only within 4–8, 8–12 and 12–16 h, respectively. The second peak of flowering was inhibited moderately in some experiments and not at all in the other ones. Use of very sensitive plants showed that DC starts losing its effectiveness already in the interval 16–20 h of darkness. Consecutive DC treatments, each 4h of darkness (0–4, 4–8, ....40–44h), after which period the plants remained in darkness and were transferred to light together at the 44th h, resulted in some fluctuations of apex growth and branching. As these fluctuations could be connected with a rhythm in cell division in the apex described by King (1975), the same experiment was repeated with plants raised under constant conditions, which should not display this type of rhythm. Indeed, the fluctuations in apex growth and branching almost disappeared. It is concluded that DC does not interfere with the timing mechanism of endogenous rhythm (the phase remains unchanged). The inability of DC to abolish the second peak of flowering suggests that endogenous rhythm of flowering cannot be explained by rhythmic production of floral stimulus.
Journal of Plant Physiology, 1999
Twenty one-day-old pea plants were used as a convenient model to investigate the release of axill... more Twenty one-day-old pea plants were used as a convenient model to investigate the release of axillary buds from apical dominance with respect to their serial position and the timing of events employed as indicators of growth changes. These were recorded in the second and fifth buds from the base, possessing the highest growth potential. The decapitation and consequent loss of apical dominance led to an increase in fresh weight of the fifth bud already after 24 h, with the similar but delayed response of the second bud. The rate of 32 P incorporation into buds had a similar pattern but appeared much earlier, as soon as 6 h after application. Decapitation significantly decreased the indole-3-acetic acid level in both buds already after 6 h. A rise in the cytokinin content was observed already after 6 h following decapitation, with the highest increment in isopentenyladenosine and zeatin riboside. IAA treatment of the decapitated plants simulated to various degrees an intact apex and eliminated the effects of decapitation. These results are in favour of both auxin and cytokinin involvement in the control of apical dominance.
Journal of Plant Growth Regulation, 1998
. Root removal enhances flowering in the short day plant Chenopodium rubrum. The extent of this... more . Root removal enhances flowering in the short day plant Chenopodium rubrum. The extent of this effect depends on the de-rooting time with respect to photoperiodic induction. The largest promotive effect is observed when de-rooting coincides with the start of the inductive treatment or, to a lesser extent, when performed before it. De-rooting 24 h after induction has no effect on flowering. The flower-inducing action of de-rooting 24 h before the start of induction is increased by benzylaminopurine (BAP), whether applied simultaneously with de-rooting or 24 h later. At the beginning of darkness, BAP inhibits flowering slightly when applied simultaneously with de-rooting but inhibits it strongly when applied 24 h later. Flowering in plants de-rooted 24 h after induction is inhibited strongly by BAP. Root removal at the beginning of inductive darkness does not change the level of endogenous cytokinins in induced shoot explants, but under continuous light the level of cytokinins in shoot explants decreases during the same period compared with the level in the shoots of intact plants. BAP does not affect the level of endogenous cytokinins in light but causes an apparent increase in induced segments. Thus, two phases of the de-rooting effect and cytokinin treatment may be distinguished: one in which flowering is enhanced by both treatments and which is linked directly to photoperiodic flower induction, and the other in which both treatments are inhibitory to flowering and which is related to morphogenetic events following induction. The time courses of the effectiveness of de-rooting and BAP treatment differ slightly, suggesting that the effect of de-rooting cannot be attributed solely to cytokinin deprivation.
Plant Growth Regulation - PLANT GROWTH REGUL, 2000
The uptake and metabolism of 3H-benzylaminopurine(3H-BAP) were studied in explanted stem pith and... more The uptake and metabolism of 3H-benzylaminopurine(3H-BAP) were studied in explanted stem pith andleaves of tobacco and in the hypocotyls and cotyledonsof cucumber. The explants were kept for 2, 5, 8 and 20h on MS medium with 0.8 mg.l-1 2,4-D,0.5 mg.l-1 BAP and 13.2 mg.l-1 aspartic acid(induction medium) with or without 3H-BAP and14C-sucrose. The highest uptake of 3H-BAPwas observed in tobacco leaves and cucumbercotyledons. The major metabolite in both species was3H-benzylaminopurine riboside (3H-BAPR). Thehighest level was found in explanted cucumbercotyledons after 20 h in culture, the lowest inexplanted tobacco stem pith. Intensive 7-glucosylationof 3H-BAP was observed in explanted tobaccoleaves after 20 h in culture, where the levels of7-glucoside of 3H-BAP and of free 3H-BAPwere equal. To study the morphogenic effect of growth regulators(BAP and 2,4-D), the explants were subcultured aftershort-term induction (20 h) to MS medium without anygrowth regulators. In most cases, incuba...
Journal of Experimental Botany, 1992
ABSTRACT A novel topographic method is described for the fully automated quantitative resolution ... more ABSTRACT A novel topographic method is described for the fully automated quantitative resolution of activity of two simultaneously applied beta tracers in plant tissues. The advantages of this method using specially developed silicon detectors are demonstrated in studying the effect of direct current on the uptake and distribution of Ca2+ and P(i) ions in leaves and stems of Chenopodium rubrum. This treatment has recently been shown to inhibit flower induction in this plant.
Biologia Plantarum, 1981
Phenylasetic acid (PAA) was found to induce ethylene formation in wheat coleoptile segments. In i... more Phenylasetic acid (PAA) was found to induce ethylene formation in wheat coleoptile segments. In its most effective concentration (9.5 mNI) PAA was by approximately 60 % less active than 0.1 mM indole-3-acetic acid (IAA). PAA-induced ethylene formation was stimulated with 0.1 mM L-methionine by 24 % and totally inhibited by 2.5 and 5 ~g ml-I aminoethoxyvinylglycin (AVG} and 10tzg ml-X cycloheximide. Cycloheximide in lower concentration (5 ptgml-X) and actinomycin D (10 ~g ml-x) inhibited PAA-induced ethylene formation by 50 % and 40 %, respectively. After the simultaneous addition of PAA and IAA ethylene formation was by 35 % lower than in the presence of IAA itself. Further, the coleoptile segments preincubated in IAA and then incubated in PAA solution produced by 35 ~o less ethylene than those incubated in plain buffer after preincubation in IAA. Quite the opposite effect was found when the segments were preineubated in PAA and then transferred into I A~ solution. This treatment resulted in 70 % 9 stimulation of ethylene formation over segments preincubated in PAA and incubated in buffer.
Biologia plantarum, 2010
The contents of endogenous free and conjugated polyamines, putrescine (Put) and spermidine (Spd),... more The contents of endogenous free and conjugated polyamines, putrescine (Put) and spermidine (Spd), were determined during 9 week of vernalization (at 5 °C) in winter wheat seedlings cultivated on Murashige and Skoog media without (MS0) and with 2 mg dm-3 zearalenone (MSZEN). At the 4 th week of chilling treatment, which is sufficient to induce generative development in 30 % of plants, the marked increase in free and conjugated forms of Put and free Spd were observed. The presence of ZEN in medium significantly accelerated the vernalization. About 20 % of plants treated with ZEN flowered already after 2 weeks and 40 % after 3 weeks of chilling. Significantly higher content of free Put was determined in roots grown on MSZEN compared with MS0 during the first 5 weeks of vernalization with maximum at the 4 th week. After germination, a marked decrease in free Spd content was observed both in plants grown on MS0 and MSZEN. Application of ZEN significantly slowed down the Spd decline in leaves and roots during the first and second week of vernalization. The content of Spd and its conjugates decreased in vernalized plants after 1 week of cultivation at 20 °C.
Biologia Plantarum, 1985
The fluctuation of free IAA under 16 h dark period, in shoot~ (receptor organs of photoporiodic i... more The fluctuation of free IAA under 16 h dark period, in shoot~ (receptor organs of photoporiodic induction) and roots of'the shor.t-day plant (SDP) Chenopodium rubrum and i,n shoots o~ the long-day plant (LDP) .Chenopodium murale is very similar. The data reflect the general adjustment of auxin level to day-length rather than changes duo to floral induction. ttowever, the shift in phasing of the circadian rhythm of flowering was accompanied by a change in the position of t~he' troughs' of free IAA levels indicating a possible relationship between the two processes. Periods of higher sensitivity to application of IAA (3. 10-dM) inhibitory to flowering have Ipeen observed both during the endogenous rhythm of flowering in the SDP C. rubrum and during induction by days of continuous illumination in the LDP C. murale. There exist commou traits in the response of LDP and of SDP Chenopodium to auxin treatment. Aminoethoxyvinylglycine (AVG), an inhibitor of ethylene biosynthesis, counteracted some flowering inhibitory effects of IAA when applied simultaneously with it. This suggests that auxin effects in modifying flowering might in fact be duo to ethylene.
Biologia Plantarum, 1990
Haploid tobacco plants (cv. Samsun) form inflorescences with a larger number of flowers than dipl... more Haploid tobacco plants (cv. Samsun) form inflorescences with a larger number of flowers than diploid plants. Leaves of haploid plants were shown to have lower free IAA level (by 40 %), higher peroxidase (by 160 %) and IAA-oxidase (by 70 %) activities and produce less ethylene (by 25 %) than leaves of corresponding diploid plants. The increase of peroxidase activity in haploids was due to the increase in the activity of the cathodic isozyme which is known to have high IAA-oxidase activity. It is proposed that higher peroxidase/IAA-oxidase activity in haploid plants may take part in IAA catabolism, at least during/a vitro culture of haploid explants. Lowered IAA level and ethylene production may then be directly correlated with a larger ntlmber of flower buds~ as a higher IAA level is generally considered to act as a background inhibitor of flowering.
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Papers by Ivana Macháčková