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1.
The relationship between elongation growth and the incorporation of [3H]gibberellin A1 ([3H]GA1) into a 2,000g pelletable (2KP) fraction from lettuce (Lactuca sativa L., cv. Arctic) hypocotyl sections has been examined. Sections were loaded with incremental amounts of GA1 under conditions where growth was arrested (5° C) or permitted (30° C) and, after 16 h, all were transferred to a GA-free
medium at 30° C. Growth and 2KP radioactivity were measured at this point and after a further 24 h in the chase medium. Uptake
was reduced by 80% at 5° C, as compared to 30° C, but 2KP labelling and protein synthesis were only reduced by half. The growth
rate of the 5° C pretreated sections during the chase period was comparable to that observed during the pulse in the 30° C
material but the dose/response relationship was flatter. Low temperature sections incorporated a much higher percentage of
GA1 uptake into the 2KP fraction (27% at maximum) but the absolute levels of labelling at this temperature were lower than those
measured at 30° C. The data are interpreted as showing that 2KP labelling is not a consequence of growth. It must either precede
response or be an unconnected concurrent process. 相似文献
2.
We have compared the effects of cycloheximide (CHI) and two other rapid and effective inhibitors of protein synthesis, pactamycin and 2-(4-methyl-2,6-dinitroanilino)-N-methyl proprionamide (MDMP), on protein synthesis, respiration, auxin-induced growth and H+-excreation of Avena sativa L. coleoptiles. All three compounds inhibit protein synthesis without affecting respiration. The effectiveness of the inhibitors against H+-excretion and growth correlates with their ability to inhibit protein synthesis. Both CHI and MDMP inhibit auxin-induced H+-excretion after a latent period of 5–8 min, and inhibit growth after a 8–10-min lag. These results support the idea that continued protein synthesis is required in the initial stages of the growth-promoting action of auxin.Abbreviations CHI
cycloheximide
- DMSO
dimethyl sulfoxide
- FC
fusicoccin
- IAA
indole-3-acetic acid
- MDMP
2-(4-methyl-2,6-dinitroanilino)-N-methyl proprionamide 相似文献
3.
Elongation growth and gibberellin (GA9) metabolism in excised hypocotyls of lettuce (Lactuca sativa L. cv. Arctic) were investigated. Exogenously supplied GA9 stimulates elongation of hypocotyl sections and this response is intermediate between that elicited by GA1 or GA20 and GA4/7 mixture. Although uptake of radioactivity from [3H]GA9 increases with time, this gibberellin does not accumulate in the tissue but is rapidly converted to a compound with HPLC properties resembling those of [3H]GA20. After 2 h incubation in [3H]GA9, the presumptive GA20 represents 90% of the acidic ethyl acetate-soluble radioactivity in the tissue. Radioactivity is also associated with an acidic butanol-soluble fraction containing two components resolvable by HVE. The major component is similar in electrophoretic properties to a GA-glucosyl ether while the other compares to a GA-glucosyl ester. Conversion of [3H]GA9 to its [3H]GA20-like metabolite is reduced by addition of carrier GA9 or GA4/7 at concentrations as low as 1 M, while GA1, GA3 and L-proline are without effect. Formation of the GA20-like compound can be blocked by the addition of 2,2-dipyridyl, and this inhibitory effect of dipyridyl can be reversed by addition of Fe2+. At 200 M dipyridyl, elongation growth as well as [3H]GA9 metabolism are reduced by 80%. The relationship of the metabolism of GA9 to the growth response is discussed.Abbreviations AB
butanol-soluble
- AE
ethyl-acetate-soluble
- GA
gibberellin
- GA1, GA4
gibberellin A1, gibberellin A4, etc.
- TLC
thin layer chromatography
- HPLC
high performance liquid chromatography
- HVE
high voltage electrophoresis 相似文献
4.
Prothallia of Lygodium japonicum (Thunb.) Sw. were aseptically cultured under white light in a mineral solution. Solvent fractionation of the resultant culture medium and subsequent preparative thinlayer chromatography yielded a fraction that induced antheridium formation and inhibited archegonium formation. Combined gas chromatography-selected ion monitoring analysis of this fraction confirmed the presence of gibberellin A9 methyl ester (GA9-me) as an antheridiogen and an inhibitor of archegonium formation. Exogenously applied [3H]GA9 was rapidly converted to [3H]GA9-me in the prothallial tissue. Authentic GA9-me was active to 10-10M in antheridium formation and to 10-9M in the inhibition of archegonium formation.Abbreviations GAs
gibberellins
- GAn
gibberellin An
- GAn
me, gibberellin An methyl ester
- TLC
thin-layer chromatography
- GCSIM
Combined gas chromatography-selected ion monitoring 相似文献
5.
A cell-free system prepared from developing seed of runner bean (Phaseolus coccineus L.) converted [14C]gibberellin A12-aldehyde to several products. Thirteen of these were identified by capillary gas chromatography-mass spectrometry as gibberellin A1 (GA1), GA4, GA5, GA6, GA15, GA17, GA19, GA20, GA24, GA37, GA38, GA44 and GA53-aldehyde, all giving mass spectra with 14C-isotope peaks. GA8 and GA28 were also identified but contained no 14C. All the [14C]GA12-aldehyde metabolites, except GA15, GA24 and GA53-aldehyde, are known endogenous GAs of P. coccineus.Abbreviations GAn
gibberellin An
- GC-MS
combined gas chromatography-mass spectrometry
- HPLC
highperformance liquid chromatography
- MVA
mevalonic acid
- S-2
2000-g supernatant 相似文献
6.
Cell-free systems were prepared from germinating seed and seedlings of Phaseolus coccineus. Gibberellin A4 (GA4)-metabolising activity was detected in vitro using preparations from roots, shoots and cotyledons of germinating seed, but only up to 24 h after imbibition. Cell-free preparations from cotyledons converted [3H]GA4 to GA1, GA34, GA4-glucosyl ester and a putative O-glucoside of GA34, and, in addition converted [3H]GA1 to GA8. Preparations from embryo tissues contained 2-hydroxylase activity, converting [3H]GA4 to GA34 and [3H]GA1 to GA8.The presence of GA-metabolising enzymes was also indicated by in-vivo feeds of [3H]GA4 to epicotyls of intact 4-d-old seedlings, which resulted in the accumulation of GA1, GA8, GA3-3-O-glucoside, GA4-glucosyl ester, GA8-2-O-glucoside and a putative O-glucoside of GA34. Gibberellin A1 was the first metabolite detected, 15 min after application of [3H]GA4, but after 24 h most of the label was associated with GA8-2-O-glucoside. Over 90% of the recovered radioactivity was found in the shoot. Within the shoot, movement was preferentially acropetal, and was not dependent upon metabolism of the applied [3H]GA4.Abbreviations DEAE
diethylaminoethyl
- GAn
gibberellin An
- GPC
gel permeation chromatography
- HPLC-RC
high performance liquid chromatography-radio counting
- S-1
1000·g supernatant
- UDP
uridine 5-diphosphate 相似文献
7.
Gibberellin metabolism in excised lettuce hypocotyls: Evidence for the formation of gibberellin A1 glucosyl conjugates 总被引:1,自引:1,他引:0
The properties of the water-soluble metabolites of [3H]gibberellin A1 ([3H]GA1) from lettuce (Lactuca sativa L.) hypocotyls were compared with those of authentic samples of gibberellin (GA) glucosyl esters and ethers. Partitioning against l-butanol at high and low pH was not an efficient method of differentiating between ester and ether conjugates of GA1 or GA3. Extraction into l-butanol at pH 2.5 was, however, useful as a group purification step. Gel-filtration on acrylamide indicated a mean molecular weight of ca. 600 for the polar material and high-voltage electrophoresis separated two compounds (LH 1 and LH 2) with differing charge properties. Both metabolites incorporated 14C from glucose and 3H from GA1. Subsequent enzymatic hydrolysis of LH 1 released material with identical properties to [14C]glucose together with a second uncharacterised component. Feeding with [3H]GA1 methyl ester greatly reduced the formation of LH 1 but not LH 2. The metabolites were provisionally identified as GA1-glucosyl ester (LH 1) and GA1-glucosyl ether (LH 2).Abbreviations GA
gibberellin
- LH1
GA3-glucosyl ester
- LH2
GA1-glucosyl ether
- HVE
high voltage paper electrophoresis
- TLC
thin-layer chromatography 相似文献
8.
J. A. D. Zeevaart 《Planta》1985,166(2):276-279
The effects of the new growth retardant tetcyclacis (TCY) on stem growth and endogenous gibberellin (GA) levels were investigated in the long-day rosette plant Agrostemma githago. Application of TCY (10 ml of a 5·10-5M solution daily) to the soil suppressed stem elongation in Agrostemma grown under long-day conditions. A total of 10 g GA1 (1 g applied on alternate days) per plant overcame the growth retardation caused by TCY.Control plants and plants treated with TCY were analyzed for endogenous GAs after exposure to nine long days. The acidic extracts were fractionated by high-performance liquid chromatography. Part of each fraction was tested in the d-5 maize bioassay, while the remainder was analyzed by combined gas chromatography-selected ion monitoring. The bioassay results indicated that the GA content of plants treated with TCY was much lower than that of untreated plants. The data obtained by gas chromatography-selected ion monitoring confirmed that the levels of seven GAs present in Agrostemma were much reduced in TCY-treated plants when compared with the levels in control plants: GA53 (13%), GA44 (0%), GA19 (1%), GA17 (33%), GA20 (15%), GA1 (4%), and epi-GA1 (13%). These results provide evidence that TCY inhibits stem growth in Agrostemma by blocking GA biosynthesis and thus lowering the levels of endogenous GAs.Abbreviations AMO-1618
2-isopropyl-4-dimethylamino-5-methylphenyl-1-piperidine-carboxylate methyl chloride
- GA(s)
gibberellin(s)
- HPLC
high-performance liquid chromatography
- TCY
Tetcyclacis (5-[4-chlorophenyl]-3,4,5,9,10-pentaaza-tetracyclo-5,4,1,02,6,08,11-dodeca-3,9-diene) 相似文献
9.
Endogenous ethylene production of tobacco leaves was similar in light and in darkness. However, the rate of conversion of exogenously applied l-aminocyclopropane-l-carboxylic acid (ACC) to ethylene was reversibly inhibited by light. Virus-stimulated ethylene production, during the hypersensitive reaction of tobacco leaves to tobacco mosaic virus, was likewise inhibited by light. Under such circumstances ethylene production is limited at the level of the conversion of ACC to ethylene. Inhibition of the increase in ACC-stimulated ethylene production by cycloheximide and 2-(4-methyl-2,6-dinitroanilino)-N-methyl-propionamide after shifting leaf discs from light to darkness indicated that de novo protein synthsis was involved. Regulation of ACC-dependent ethylene production by reversible oxidation/reduction of essential SH groups, as suggested by Gepstein and Thimann (1980, Planta 149, 196–199) could be excluded. Instead, regulation of the ACC-converting enzyme at the level of both synthesis/degradation and activation/inactivation is suggested. Phytochrome was not involved in light inhibition, but low intensities of either red or blue light decreased the rate of ACC conversion. Dichlorophenyldimethylurea counteracted the inhibitory effect of light, indicating that (part of) the photosynthetic system is involved in the light inhibition. The ethylene production of Pharbitis cotyledons grown in darkness or light, either in the presence of absence of the inhibitor of carotenoid synthesis, SAN 9789 (norflurazon), supported this view.Abbreviations ACC
1-aminocyclopropane-1-carboxylic acid
- DCMU
dichlorophenyldimethylurea
- MDMP
2-(4-methyl-2,6-dinitroanilino)-N-methyl-propionamide
- SAM
S-adenosylmethionine
- SH groups
sulfhydryl groups
- TCA
trichloroacetic acid
- TMV
tobacco mosaic virus 相似文献
10.
Endogenous pools of presumptive gibberellin (GA) glucosyl conjugates of Phaseolus coccineus were metabolically labelled by feeding of [3H]GA1 to immature fruits. The [3H]GA1 glucoside fraction was isolated and the main constituent tentatively identified by enzymic hydrolysis, ion exchange chromatography and elution volume on HPLC-RC as GA1-3-0--D-glucopyranoside. 相似文献
11.
John L. Stoddart 《Planta》1984,161(5):432-438
Growth parameters were determined for tall (rht3) and dwarf (Rht3) seedlings of wheat (Triticum aestivum L.). Plant statures and leaf length were reduced by 50% in dwarfs but root and shoot dry weights were less affected. Leaves of dwarf seedlings had shorter epidermal cells and the numbers of cells per rank in talls and dwarfs matched the observed relationships in overall length. Talls grew at twice the rate of dwarfs (2.3 compared with 1.2 mm h-1). [3H]Gibberellin A1 ([3H]GA1) was fed to seedlings via the third leaf and metabolism was followed over 12 h. Immature leaves of tall seedlings transferred radioactivity rapidly to compounds co-chromatographing with [3H]gibberellin A8 ([3H]GA8) and a conjugate of [3H]GA8, whereas leaves of dwarf seedlings metabolised [3H]GA1 more slowly. Roots of both genotypes produced [3H]GA8-like material at similar rates. Isotopic dilution studies indicated a reduced 2-hydroxylation capacity in dwarfs, but parallel estimates of the endogenous GA pool size, obtained by radioimmunoassay, indicated a 12–15 times higher level of GA in the dwarf immature leaves. Dwarfing by the Rht3 gene does not appear to operate through enhanced, or abnormal metabolism of active gibberellins and the act of GA metabolism does not bear an obligate relationship to the growth response.Abbreviations GAn
gibberellin An
- HPLC
high-performance liquid chromatography 相似文献
12.
The fate of [14C] gibberellin A3 and [3H] gibberellin A1 was examined in senescing fruit of Shamouti orange (Citrus sinensis L. Osbeck) and tomato (Lycopersicon esculentum Mill.). Gibberellin A3 was highly persistent in Citrus peel (t 1/2=18 days) and to a lesser degree in tomato (t 1/2=5.5 days). Ethylene and ethephon caused a slight enhancement of gibberellin A3 metabolism in Citrus and tomato fruit, respectively. Gibberellin A1 was metabolized by Citrus peel at a relatively high rate (t 1/2 < 24 h) and ethylene slightly reduced this rate. It is concluded that the ethylene-induced enhancement of senescence does not involve major effects on the deactivation of applied gibberellins.Abbreviations GA3
gibberellin A3
- GA1
gibberellin A1 相似文献
13.
Maria Kwiatkowska 《Planta》1991,183(2):294-299
Translocation of [14C]gibberellic acid into antheridial cells of Chara vulgaris L. was investigated in relation to the presence of symplasmic connections between the antheridium and the thallus. It was found that manubria, capitular cells, and antheridial filaments were about three-fold more strongly labelled in young antheridia connected to the thallus by plasmodesmata than in older antheridia in which spontaneous symplasmic isolation had occurred. Plasmolytically induced symplasmic isolation of young antheridia severely diminished the radioactivity of all the cells, down to the level characteristic for spontaneously isolated antheridia. It is concluded that plasmodesmata are the main channel of gibberellin transport into antheridia. The change in the character of symplasmic connections during the course of morphogenesis might, among other events, constitute a signal determining a shift of cell metabolism in a new direction, in response to a rapid change in gibberellin level.Abbreviations GA(n)
gibberellin (An)
- GA3
gibberellic acid
- IAA
indole-3-acetic acid
This study was supported by the Polish Academy of Sciences research project CPBP 04.01.5.05. 相似文献
14.
The persistence of gibberellin A3 on plant surfaces was examined using fruit of Marsh seedless grapefruit (Citrus paradisi Macf.) and an inert glass model system. 14C-gibberellin A3 was applied to surfaces in aqueous treatment solutions or in waxing solutions. Dried-out treatment residues were removed by washing and analyzed for total and GA3-like radioactivity. Gibberellin A3 persisted without significant loss for at least 7 d in aqueous treatment solutions (pH 4.0 or 6.2) but was less persistent in the pH 10.4 waxing solution (t1/2=7 d).Loss of total peel surface radioactivity was fast during the first 3 days, slowing down afterwards. After 14 days 73% of the initial radioactivity could still be recovered from fruit peel surface and 70% of the recovered radioactivity was still in the form of gibberellin A3. Gibberellin A3 was somewhat more persistent in residues from pH 4 than pH 7 treatment solutions. Light had a slight enhancing effect on gibberellin A3 decomposition on fruit peel under growth chamber conditions. After 12 d at 100% relative humidity, 88% of the radioactivity on glass surfaces was still in the form of gibberellin A3, as against 45% at a relative humidity of 50%. Simulated field conditions, combining daily fluctuations in light, temperature and relative humidity, markedly enhanced gibberellin A3 decomposition on glass surfaces (t1/2=2 d). Gibberellin A3 was very persistent (90% after 9 d) in the waxing residues on fruit peel surface.Abbreviations GA3
gibberellin A3
- RH
relative humidity 相似文献
15.
Timothy J. Ingram James B. Reid Ian C. Murfet Paul Gaskin Christine L. Willis Jake MacMillan 《Planta》1984,160(5):455-463
The influence of the Na and Le genes in peas on gibberellin (GA) levels and metabolism were examined by gas chromatographic-mass spectrometric analysis of extracts from a range of stem-length genotypes fed with [13C, 3H]GA20. The substrate was metabolised to [13C, 3H]GA1, [13C, 3H]GA8 and [13C, 3H]GA29 in the immature, expanding apical tissue of all genotypes carrying Le. In contrast, [13C, 3H]GA29 and, in one line, [13C, 3H]GA29-catabolite, were the only products detected in plants homozygous for the le gene. These results confirm that the Le gene in peas controls the 3-hydroxylation of GA20 to GA1. Qualitatively the same results were obtained irrespective of the genotype at the Na locus. In all Na lines the [13C, 3H]GA20 metabolites were considerably diluted by endogenous [12C]GAs, implying that the metabolism of [13C, 3H]GA20 mirrored that of endogenous [12C]GA20. In contrast, the [13C, 3H]GA20 metabolites in na lines showed no dilution with [12C]GAs, confirming that the na mutation prevents the production of C19-GAs. Estimates of the levels of endogenous GAs in the apical tissues of Na lines, made from the 12C:13C isotope ratios and the radioactivity recovered in respective metabolites, varied between 7 and 40 ng of each GA per plant in the tissue expanded during the 5 d between treatment with [13C, 3H]GA20 and extraction. No [12C]GA1 and only traces of [12C]GA8 (in one line) were detected in the two Na le lines examined. These results are discussed in relation to recent observations on dwarfism in rice and maize.Abbreviations GAn
gibberellin An
- GC-MS
gas chromatography-mass spectrometry
- HPLC
high-pressure liquid chromatography 相似文献
16.
Summary Movement of both [3H]GA1 and [14C]GA3 through root segments from P. coccineus seedlings was basipetally polarised. The basipetal/acropetal ratio of radioactivity from [3H]GA1 in agar receiver blocks was 9.2 for apical, elongating segments, and 4.0 for more basal, non-elongating segments. Polarity of gibberellin transport was restricted to the stele, and absent from cortical tissues. Transport of [14C]IAA through root segments to agar receivers was preferentially acropetal, particularly so in the stele. Despite the existence of basipetal polarity of gibberellin transport in the root, [3H]GA1 injected into cotyledons moved into and acropetally along the seedling root. 相似文献
17.
18.
Summary When aleurone layers were treated with labeled gibberellin A1 (3H-GA1), gibberellin A5 (3H-GA5) and the methyl ester of 3H-GA5 (3H-GA5-ME), radioactivity was accumulated by the tissue for a period of 20–30 h. After this time, radioactivity was released into the medium. Concomitantly, ribonuclease was also liberated by the tissue. The radioactivity accumulated by aleurone layers was associated with polar metabolites of the respective GAs, and the extent of extent of accumulation was a function of the degree of GA metabolism (GA5-ME>GA5>GA1). Accumulation of radioactivity was inhibited in the cold and by the metabolic poisons NaF and dinitrophenol. This was thought to be due to inbition of GA metabolism. The accumulation of 3H-GA1 in aleurone tissue did not reach saturation when unlabeled GA3 up to 10-2 M was added to the incubation medium.Abbreviations GA
gibberellin
- GA5
ME, gibberellin A5 methyl ester
- RNase
ribonuclease 相似文献
19.
J. L. Stoddart 《Planta》1972,107(1):81-88
Summary The biological activities of gibberellin A9 (GA9), gibberellin A12 (GA12) and monofluoro-analogues (F-GA9 and F-GA12), substituted in the 1 -methyl group, were compared in the barley endosperm, cucumber hypocotyl, lettuce hypocotyl, Meteor dwarf pea, dwarf-5 maize and Rumex leaf disc assays. In most cases the fluorosubstituted compounds had a potency similar to, or less than, the relevant unmodified gibberellin but, in the lettuce assay, F-GA9 was approximately 5 times more active than GA9 up to a dose rate of 10-1 g.A 27–30% mixture of fluorogibberellin A3 (F-GA3) in GA3 had a lower activity than 100% GA3 in the barley endosperm, lettuce hypocotyl and dwarf maize assays. This suggested that pure F-GA3 may be a competitive inhibitor of GA3 action. The findings are discussed in the context of the structure/activity relationships of the gibberellins. 相似文献
20.
Spray Clive Phinney Bernard O. Gaskin Paul Gilmour Sarah J. MacMillan Jake 《Planta》1984,160(5):464-468
[13C, 3H]Gibberellin A20 (GA20) has been fed to seedlings of normal (tall) and dwarf-5 and dwarf-1 mutants of maize (Zea mays L.). The metabolites from these feeds were identified by combined gas chromatography-mass spectrometry. [13C, 3H]Gibberellin A20 was metabolized to [13C, 3H]GA29-catabolite and [13C, 3H]GA1 by the normal, and to [13C, 3H]GA29 and [13C, 3H]GA1 by the dwarf-5 mutant. In the dwarf-1 mutant, [13C, 3H]GA20 was metabolized to [13C, 3H]GA29 and [13C, 3H]GA29-catabolite; no evidence was found for the metabolism of [13C, 3H]GA20 to [13C, 3H]GA1. [13C, 3H]Gibberellin A8 was not found in any of the feeds. In all feeds no dilution of 13C in recovered [13C, 3H]GA20 was observed. Also in the dwarf-5 mutant, the [13C]label in the metabolites was apparently undiluted by endogenous [13C]GAs. However, dilution of the [13C]label in metabolites from [13C, 3H]GA20 was observed in normal and dwarf-1 seedlings. The results from the feeding studies provide evidence that the dwarf-1 mutation of maize blocks the conversion of GA20 to GA1.Abbreviations GAn
gibberellin An
- GC-MS
combined gas chromatography-mass spectrometry
- HPLC
high-performance liquid chromatography
- RP
reverse phase 相似文献