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1.
Metabolism of Gibberellin A(12) and A(12)-Aldehyde in Developing Seeds of Pisum sativum L 总被引:1,自引:0,他引:1
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Metabolism of [14C]gibberellin (GA) A12 (GA12) and [14C]gibberellin A12-aldehyde (GA12-aldehyde) was examined in cotyledons and seed coats from developing seeds of pea (Pisum sativum L.). Both were metabolized to only 13-hydroxylated GAs in cotyledons but to 13-hydroxylated and non-13-hydroxylated GAs in seed coats. The metabolism of [14C]GA12 was slower in seed coats than in cotyledons. [14C]GA12-aldehyde was also metabolized to conjugates in seed coats. Seed coat [14C]-metabolites produced from [14C]GA12-aldehyde were isolated by high-performance liquid chromatography (HPLC). Conjugates were base hydrolyzed and the free GAs reisolated by HPLC and identified by gas chromatography-mass spectrometry. [14C]GA53-aldehyde, [14C]GA12-aldehyde conjugate, and [14C]GA53-aldehyde conjugate were major metabolites produced from [14C]GA12-aldehyde by seed coats aged 20-22 days or older. The dilution of 14C in these compounds by 12C, as compared to the supplied [14C]GA12-aldehyde, indicated that they are endogenous. Feeding [14C]GA53-aldehyde led to the production of [14C]GA53-aldehyde conjugate in seed coats and shoots and also to 13-hydroxylated GAs in shoots. Labeled GAs, recovered from plant tissue incubated with either [14C]GA12, [14C]GA12-aldehyde, or [3H]GA9, were used as appropriate markers for the recovery of endogenous GAs from seed coats or cotyledons. These GAs were purified by HPLC and identified and quantified by gas chromatography-mass spectrometry. GA15, GA24, GA9, GA51, GA51-catabolite, GA20, GA29, and GA29-catabolite were detected in seed coats, whereas GA9, GA53, GA44, GA19, GA20, and GA29 were found in cotyledons. The highest GA levels were for GA20 and GA29 in cotyledons (783 and 912 nanograms per gram fresh weight, respectively) and for GA29 and GA29-catabolite in seed coats (1940 and > 1940 nanograms per gram fresh weight, respectively). 相似文献
2.
Experiments were designed to test the hypothesis that the labeled products recovered from plant tissue incubated with [14C]GA12-7-aldehyde ([14C]GA12ald) would serve as appropriate [14C]markers for the recovery of naturally-occurring gibberellins (GAs). The [14C]GA12ald (about 200 millicuries per millimole) was synthesized from pumpkin endosperm using [4,5-14C]mevalonic acid. It was added to the adaxial surface of isolated pea cotyledons at 22 days after flowering. Products recovered after 0.5 and 4.0 hour incubations yielded four major peaks which were separated by high performance liquid chromatography (HPLC). These products were purified by multiple-column HPLC using on-line radioactivity detection. They were then added as [14C]markers to two unlabeled pea extracts. In general, preparative HPLC followed by further HPLC purification resulted in a single UV-absorbing peak co-eluting with each [14C]marker. These [14C] and UV-absorbing peaks were shown to contain GA53, GA44, GA20, GA19, and GA17 by GC-MS. The finding of GA53 is novel; all others have previously been found in pea. Endogenous GAs of pea were thus readily detected using [14C]GA12ald metabolites as [14C]markers to recover naturally occurring GAs suggesting that the method may be applicable in detecting naturally occurring GAs in other species. 相似文献
3.
Gibberellins (GAs) are either required for, or at least promote, the growth of the pea (Pisum sativum L.) fruit. Whether the pericarp of the pea fruit produces GAs in situ and/or whether GAs are transported into the pericarp from the developing seeds or maternal plant is currently unknown. The objective of this research was to investigate whether the pericarp tissue contains enzymes capable of metabolizing GAs from [14C]GA12-7-aldehyde ([14C]GA12ald) to biologically active GAs. The metabolism of GAs early in the biosynthetic pathway, [14C]GA12 and [14C]GA12ald, was investigated in pericarp tissue isolated from 4-day-old pea fruits. [14C]GA12ald was metabolized primarily to [14C]GA12ald-conjugate, [14C]GA12, [14C]GA53, and polar conjugate-like products by isolated pericarp. In contrast, [14C]GA12 was converted primarily to [14C]GA53 and polar conjugate-like products. Upon further investigations with intact 4-day-old fruits on the plant, [14C]GA12 was found to be converted to a product which copurified with endogenous GA20. Lastly, [2H]GA20 and [2H]GA1 were recovered 48 hours after application of [2H]- and [14C]GA53 to pericarp tissue of intact 3-day-old pea fruits. These results demonstrate that pericarp tissue metabolizes GAs and suggests a function for pericarp GA metabolism during fruit growth. 相似文献
4.
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
5.
Pea fruit (Pisum sativum L.) is a model system for studying the effect of seeds on fruit growth in order to understand coordination of organ development. The metabolism of 14C-labeled gibberellin A12 (GA12) by pea pericarp was followed using a method that allows access to the seeds while maintaining pericarp growth in situ. Identification and quantitation of GAs in pea pericarp was accomplished by combined gas chromatography-mass spectrometry following extensive purification of the putative GAs. Here we report for the first time that the metabolism of [14C]GA12 to [14C]GA19 and [14C]GA20 occurs in pericarp of seeded pea fruit. Removal of seeds from the pericarp inhibited the conversion of radiolabeled GA19 to GA20 and caused the accumulation of radiolabeled and endogenous GA19. Deseeded pericarp contained no detectable GA20, GA1, or GA8, whereas pericarp with seeds contained endogenous and radiolabeled GA20 and endogenous GA1. These data strongly suggest that seeds are required for normal GA biosynthesis in the pericarp, specifically the conversion of GA19 to GA20. 相似文献
6.
In G2 peas (Pisum sativum L.) apical senescence occurs only in long days (LD), and indeterminate growth is associated with elevated gibberellin (GA) levels in the shoot in short days (SD). Metabolism of GA12 aldehyde was investigated by feeding shoots grown in SD or LD with [14C]GA12 aldehyde through the cut end of the stem for 0.5 to 6 hours in the light and analyzing the tissue extract by high performance liquid chromatography. More radioactive products were detected than can be accounted for by the two GA metabolic pathways previously known to be present in peas. Three of the major products appear to be GA conjugates, but an additional pathway(s) of GA metabolism may be present. The levels of putative C20 GAs, [14C]GA53, [14C]GA44, [14C]GA19, and/or [14C] GA17, were all elevated in SD as compared to LD. Putative [14C]GA, was slightly higher in LD than in SD. Putative [14C]GA53 was a major metabolite after 30 minutes of treatment in SD but had declined after longer treatment times to be replaced by elevated levels of putative [14C] GA44 and [14C]GA19/17. Metabolism of GA20 was slow in both photoperiods. Although GA20 and GA19 are the major endogenous GAs as determined by gas chromatography-mass spectrometry, putative [14C]GA20 and [14C]GA19 were never major products of [14C]GA12 aldehyde metabolism. Thus, photoperiod acts in G2 peas to change the rate of GA53 production from GA12 aldehyde, with the levels of the subsequent GAs on the 13-OH pathway being determined by the amount of GA53 being produced. 相似文献
7.
Gibberellin (GA) metabolism from GA12-aldehyde was studied in cell-free systems from 2-d-old germinating embryos of barley. [14C]- or [17-2H2]Gibberellins were used as substrates and all products were identified by combined gas chromatography-mass spectrometry. Stepwise analysis demonstrated the conversion of GA12-aldehyde via the 13-deoxy pathway to GA51 and via the 13-hydroxylation pathway to GA29, GA1 and GA8. In addition, GA3 was formed from GA20 via GA5. We conclude that the embryo is capable of producing gibberellins that can induce -amylase production in the aleurone layer. There was no evidence for 12- or 18-hydroxylation and GA4 was neither synthesised nor metabolised by the system. All metabolically obtained GAs, with the exception of GA3, were also found as endogenous components of the cell-free system in spite of ammonium-sulfate precipitation and desalting steps.Abbreviations GAn
gibberellin An
- GC-MS
combined gas chromatography-mass spectrometry
- HPLC
high-performance liquid chromatography
We thank Mrs. G. Bodtke and Mrs. B. Schattenberg for preparing the barley embryos and the Deutsche Forschungsgemeinschaft for supporting this work. 相似文献
8.
《Phytochemistry》1987,26(9):2485-2488
Endogenous gibberellins (GAs) in Chinese Spring wheat seedlings were isolated by high performance liquid chromatography (HPLC) and identified by combined capillary gas chromatography-selected ion monitoring (GC-SIM). Gibberellins A1, A3, A19, A20, A44, and A53 were identified in the shoots, A19 and A20 in the roots. The identification of these 13-hydroxylated GAs demonstrates the presence of the early-13-hydroxylation pathway in wheat seedlings. Based on peak area of total ion response of five characteristic ions by GC-SIM, the approximate levels of GAs in the shoots is GA44 > GA19 > GA1 = GA3 > GA20 for the non-vernalized wheat seedlings, and GA44 > GA19 > GA53 = GA3 > GA1 = GA20 for the vernalized wheat seedlings. The C20 GAs, GA53, GA44 and GA19, are present in shoots of the vernalized (flowering) wheat seedlings at somewhat higher levels than that in the non-vernalized (rapidly growing) wheat seedlings. Approximate levels of the C19 GAs, GA20, GA1 and GA3 were lower in the shoots of the vernalized wheat seedlings than in the non-vernalized wheat seedlings. The conversion of GA19 to GA20 (C20 to C19 GAs) may be a rate-limiting step in the vernalized wheat seedlings. 相似文献
9.
Metabolism of gibberellin a(12)-7-aldehyde by soybean cotyledons and its use in identifying gibberellin a(7) as an endogenous gibberellin 总被引:2,自引:1,他引:1
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The level of gibberellin(GA)-like material in cotyledons of soybean (Glycine max L.) was highest at mid-pod fill—about 10 nanograms GA3 equivalents per gram fresh weight of tissue, assayed in the immersion dwarf rice bioassay. This amount is about 1000-fold less than levels in Pisum and Phaseolus seed, other legume species whose spectrum of endogenous gibberellins (GAs) is well known. The metabolism of [14C]-GA12-7-aldehyde (GA12ald)—the universal GA precursor—by intact, mid-pod-fill, soybean cotyledons and their cell-free extracts was investigated. In 4 hours, extracts converted GA12ald to two products—[14C]GA12 (42% yield) and [14C]GA15 (7%). Within 5 minutes, intact embryos converted GA12ald to [14C]GA12 and [14C]GA15 in 15% yield; 4 hour incubations afforded at least 22 products (96% total yield). The putative [14C]GA12 was identified as a product of [14C]GA12ald metabolism on the basis of co-chromatography with authentic GA12 on a series of reversed and normal phase high pressure liquid chromatography (HPLC) and thin-layer chromatography (TLC) systems, and by a dual feed of the putative [14C]GA12 and authentic [14C]GA12 to cotyledons of both peas and soybeans. The [14C]GA15 was identified as a metabolite of [14C]GA12ald by capillary gas chromatography (GC)-mass-spectrometry-selected ion monitoring, GC-radiocounting, HPLC, and TLC. By adding the [14C] metabolites of [14C]GA12ald to a different and larger extract (about 0.2 kg fresh weight of soybean reproductive tissue) and purifying endogenous substances co-chromatographing with these metabolites, at least two GA-like substances were obtained and one identified as GA7 by GC-mass spectrometry. Since [14C]GA9 was not found as a [14C]metabolite of [14C]GA12ald, soybean embryos might have a pathway for biosynthesis of active, C-19 gibberellins like that of the cucurbits; GA12ald → GA12 → GA15 → GA24 → GA36 → GA4 → GA7. 相似文献
10.
The biosynthetic steps from gibberellin A12-aldehyde (GA12-aldehyde) to C19-GAs were studied by means of a cell-free system from the embryos of immature Phaseolus vulgaris seeds. Stable-isotope-labeled GAs were used as substrates and the products were identified by gas chromatography-mass spectrometry. Gibberellin A12-aldehyde was converted to GA4 via non-hydroxylated intermediates and to GA1 via 13-hydroxylated intermediates. 13-Hydroxylation took place at the beginning of the pathway by the conversion of GA12-aldehyde to GA53-aldehyde. The conversion of GA20 to GA5 and GA6 was also shown but no 2-hydroxylating activity was found. Endogenous GAs from embryos and testas of 17-dold seeds were re-examined by gas chromatography-selected ion monitoring using stable-isotopelabeled GAs as internal standards. Gibberellins A9, A12, A15, A19, A23, A24, and A53 were identified for the first time in P. vulgaris, in addition to GA1, GA4, GA5, GA6, GA8, GA17, GA20, GA29, GA37, GA38 and GA44, which were previously known to occur in this species. The levels of all GAs, except the 2-hydroxylated ones, were greater in the embryos than in the testas. Conversely, the contents of GA8 and GA29, both 2-hydroxylated, were much higher in the testas than in the embryos.Abbreviations GAn
gibberellin An
- GC-MS
gas chromatography-mass spectrometry
- GC-SIM
gas chromatography-selected ion monitoring
- HPLC
high-performance liquid chromatography
- TLC
thin-layer chromatography
-
m/z
ion of mass 相似文献
11.
Gibberellin metabolism in cell-free extracts from spinach leaves in relation to photoperiod 总被引:19,自引:12,他引:7
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Cell-free extracts capable of converting [14C]-labeled gibberellins (GAs) were prepared from spinach (Spinacia oleracea L.) leaves. [14C]-labeled GAs, prepared enzymically from [14C]mevalonic acid, were incubated with these extracts, and products were identified by gas chromatography-mass spectrometry. The following pathway was found to operate in extracts from spinach leaves grown under long day (LD) conditions: GA12 → GA53 → GA44 → GA19 → GA20. The pH optima for the enzymic conversions of [14C]GA53, [14C]GA44 and [14C]GA19 were approximately 7.0, 8.0, and 6.5, respectively. These three enzyme activities required Fe2+, α-ketoglutarate and O2 for activity, and ascorbate stimulated the conversion of [14C]GA53 and [14C]GA19. Extracts from plants given LD or short days (SD) were examined, and enzymic activities were measured as a function of exposure to LD, as well as to darkness following 8 LD. The results indicate that the activities of the enzymes oxidizing GA53 and GA19 are increased in LD and decreased in SD or darkness, but that the enzyme activity oxidizing GA44 remains high irrespective of light or dark treatment. This photoperiodic control of enzyme activity is not due to the presence of an inhibitor in plants grown in SD. These observations offer an explanation for the higher GA20 content of spinach plants in LD than in SD. 相似文献
12.
Thermoinductive Regulation of Gibberellin Metabolism in Thlaspi arvense L. : I. Metabolism of [H]-ent-Kaurenoic Acid and [C]Gibberellin A(12)-Aldehyde
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Field pennycress (Thlaspi arvense L.) is a winter annual crucifer with a cold requirement for stem elongation and flowering. In the present study, the metabolism of exogenous [2H]-ent-kaurenoic acid (KA) and [14C]-gibberellin A12-aldehyde (GA12-aldehyde) was compared in thermo- and noninduced plants. Thermoinduction greatly altered both quantitative and qualitative aspects of [2H]-KA metabolism in the shoot tips. The rate of disappearance of the parent compound was much greater in thermoinduced shoot tips. Moreover, there was 47 times more endogenous KA in noninduced than in thermoinduced shoot tips as determined by combined gas chromatography-mass spectrometry (GC-MS). The major metabolite of [2H]-KA in thermoinduced shoot tips was a monohydroxylated derivative of KA, while in noninduced shoot tips, the glucose ester of the hydroxy KA metabolite was the main product. Gibberellin A9 (GA9) was the only GA in which the incorporation of deuterium was detected by GC-MS, and this was observed only in thermoinduced shoot tips. The amount of incorporation was small as indicated by the large dilution by endogenous GA9. In contrast, thermo- and noninduced leaves metabolized exogenous [2H]-KA into GA20 equally well, although the amount of conversion was also limited. These results are consistent with the suggestion (JD Metzger [1990] Plant Physiol 94: 000-000) that the conversion of KA in to GAs is under thermoinductive control only in the shoot tip, the site of perception for thermoinductive temperatures in field pennycress. There were essentially no differences in the qualitative or quantitative distribution of metabolites formed following the application of [14C]-GA12-aldehyde to the shoot tips of thermo- or noninduced plants. Thus, the apparent thermoinductive regulation of the KA metabolism into GAs is probably limited to the two metabolic steps involved in converting KA to GA12-aldehyde. 相似文献
13.
The identification and metabolism of GA9 and its metabolites in seed coats and shoots of pea,line G2 总被引:1,自引:0,他引:1
[3H]gibberellin A9 was applied to shoots or seed parts of G2 pea to produce radiolabeled metabolites. These were used as markers during purification for the recovery of endogenous GA9 and its naturally occurring metabolites. GA9 and its metabolites were purified by HPLC, derivatized and examined by GC-MS. Endogenous GA9, GA20, GA29 and GA51 were identified in pea shoots and seed coats. GA51-catabolite and GA29-catabolite were also detected in seed coats. GA70 was detected in seed coats following the application of 1 g of GA9. Applied [3H]GA9 was metabolized through both the 13-hydroxylation and 2-hydroxylation pathways. Labeled metabolites were tentatively identified on the basis of co-chromatography on HPLC with endogenous compounds identified by GC-MS. In shoots [3H]GA51 and [3H]GA51-catabolite were the predominant metabolites after 6 hrs, but by 24 hrs there was little of these metabolites remaining, while [3H]GA29-catabolite and an unidentified metabolite predominated. In seed coats [3H]GA51 was the initial product, later followed by [3H]GA51-catabolite and an unidentified metabolite (different from that in shoots), with lesser amounts of [3H]GA20, [3H]GA29 and [3H]GA29-catabolite. [3H]GA70 was a very minor product in both cases. [3H]GA9 was not metabolized by pea cotyledons.Edited by T.J. Gianfagna.Author for correspondence 相似文献
14.
Qualitative and Quantitative Analyses of Gibberellins in Vegetative Shoots of Normal, dwarf-1, dwarf-2, dwarf-3, and dwarf-5 Seedlings of Zea mays L 总被引:18,自引:7,他引:11
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Fujioka S Yamane H Spray CR Gaskin P Macmillan J Phinney BO Takahashi N 《Plant physiology》1988,88(4):1367-1372
Gibberellins A12 (GA12), GA53, GA44, GA19, GA17, GA20, GA29, GA1, and GA8 have been identified from extracts of vegetative shoots of normal (wild type) maize using full scan capillary gas chromatography-mass spectrometry and Kovats retention indices. Seven of these gibberellins (GAs) have been quantified by capillary gas chromatography-selected ion monitoring using internal standards of [14C4]GA53, [14C4]GA44, [2H2] GA19, [13C1]GA20, [13C1]GA29, [13C1]GA1, and [13C1]GA8. Quantitative data from extracts of normal, dwarf-1, dwarf-2, dwarf-3, and dwarf-5 seedlings support the operation of the early 13-hydroxylation pathway in vegetative shoots of Zea mays. These data support the positions in the pathway blocked by the mutants, previously assigned by bioassay data and metabolic studies. The GA levels in dwarf-2, dwarf-3, and dwarf-5 were equal to, or less than, 2.0 nanograms per 100 grams fresh weight, showing that these mutants are blocked for steps early in the pathway. In dwarf-1, the level of GA1 was very low (0.23 nanograms per 100 grams fresh weight) and less than 2% of that in normal shoots, while GA20 and GA29 accumulated to levels over 10 times those in normals; these results confirm that the dwarf-1 mutant blocks the conversion of GA20 to GA1. Since the level of GAs beyond the blocked step for each mutant is greater than zero, each mutated gene probably codes for an altered gene product, thus leading to impaired enzyme activities. 相似文献
15.
Theodor Lange 《Planta》1994,195(1):108-115
Gibberellin (GA) 20-oxidase was purified to apparent homogeneity from Cucurbita maxima endosperm by fractionated ammonium-sulphate precipitation, gel-filtration chromatography and anion-exchange and hydrophobic-interaction high-performance liquid chromatography (HPLC). Average purification after the last step was 55-fold with 3.9% of the activity recovered. The purest single fraction was enriched 101-fold with 0.2% overall recovery. Apparent relative molecular mass of the enzyme was 45 kDa, as determined by gel-filtration HPLC and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, indicating that GA 20-oxidase is probably a monomeric enzyme. The purified enzyme degraded on two-dimensional gel electrophoresis, giving two protein spots: a major one corresponding to a molecular mass of 30 kDa and a minor one at 45 kDa. The isoelectric point for both was 5.4. The amino-acid sequences of the amino-terminus of the purified enzyme and of two peptides from a tryptic digest were determined. The purified enzyme catalysed the sequential conversion of [14C]GA12 to [14C]GA15, [14C]GA24 and [14C]GA25, showing that carbon atom 20 was oxidised to the corresponding alcohol, aldehyde and carboxylic acid in three consecutive reactions. [14C]Gibberellin A53 was similarly converted to [14C]GA44, [14C]GA19, [14C]GA17 and small amounts of a fourth product, which was preliminarily identified as [14C]GA20, a C19-gibberellin. All GAs except [14C]GA20 were identified by combined gas chromatography-mass spectrometry. The cofactor requirements in the absence of dithiothreitol were essentially as in its presence (Lange et. al, Planta 195, 98–107, 1994), except that ascorbate was essential for enzyme activity and the optimal concentration of catalase was lower. 相似文献
16.
The role of gibberellins A1 and A3 in fruit growth of Pisum sativum L. and the identification of gibberellins A4 and A7 in young seeds 总被引:2,自引:0,他引:2
Maria J. Rodrigo José L. García-Martínez Cristina M. Santes Paul Gaskin Peter Hedden 《Planta》1997,201(4):446-455
Gibberellins A1 and A3 are the major physiologically active gibberellins (GAs) present in young fruit of pea (Pisum sativum L.). The relative importance of these GAs in controlling fruit growth and their biosynthetic origins were investigated in
cv. Alaska. In addition, the non-13-hydroxylated active GAs, GA4 and GA7, were identified for the first time in young seeds harvested 4 d after anthesis, although they are minor components and are
not expected to play major physiological roles. The GA1 content is maximal in seeds and pods at 6 d after anthesis, the time of highest growth-rate of the pod (Garcia-Martinez et
al. 1991, Planta 184: 53–60), whereas gibberellic acid (GA3), which is present at high levels in seeds 4–8 d after anthesis, has very low abundance in pods. Gibberellins A19, A20 and A29 are most concentrated in seeds at, or shortly after, anthesis and their abundance declines rapidly with development, concomitant
with the sharp increase in GA1 and GA3 content. Application of GA1 or GA3 to the leaf subtending an emasculated flower stimulated parthenocarpic fruit development. Measurement of the GA content of
the pods at 4 d after anthesis indicated that only 0.002–0.5% of the applied GA was transported to the fruit, depending on
dose. There was a linear relationship between GA1 content and pod weight up to about 2 ng · (g FW)−1, whereas no such correlation existed for GA3 content. The concentration of endogenous GA1 in pods from pollinated ovaries is just sufficient to give the maximum growth response. It is concluded that GA1, but not GA3, controls pod growth in pea; GA3 may be involved in early seed development. The distribution of GAs within the seeds at 4 d post anthesis was also investigated.
Most of the GA1, GA8, GA19, GA20 and GA29 was present in the testa, whereas GA3 was distributed equally between testa and endosperm and GA4 was localised mainly in the endosperm. Of the GAs analysed, only GA3 and GA20 were detected in the embryo. Metabolism experiments with intact tissues and cell-free fractions indicated compartmentation
of GA biosynthesis within the seed. Using 14C-labelled GA12, GA9, 2,3-didehydroGA9 and GA20 as substrates, the testa was shown to contain 13-hydroxylase and 20-oxidase activities, the endosperm, 3β-hydroxylase and
20-oxidase activities. Both tissues also produced 16,17-dihydrodiols. However, GA1 and GA3 were not obtained as products and it is unlikely that they are formed via the early 13-hydroxylation pathway. [14C]gibberellin A12, applied to the inside surface of pods in situ, was metabolised to GA19, GA20, GA29, GA29-catabolite, GA81 and GA97, but GA1 was not detected. Gibberellin A20 was metabolised by this tissue to GA29 and GA29-catabolite.
Received: 23 July 1996 / Accepted: 2 September 1996 相似文献
17.
Comparison of the levels of six endogenous gibberellins in roots and shoots of spinach in relation to photoperiod 总被引:1,自引:1,他引:0
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This communication describes the distribution of gibberellins (GAs) in roots and shoots of spinach in relation to photoperiod. From previous work (Metzger, Zeevaart 1980 Plant Physiol 65: 623-626) shoots were known to contain GA53, GA44, GA19, GA17, GA20, and GA29. We now show by combined gas chromatography—mass spectrometry that roots contain GA44, GA19, and GA29. Trace amounts of GA53 were detected by combined gas chromatography—selected ion current monitoring. Neither GA17 nor GA20 were detected in root extracts. Analysis by the d-5 corn bioassay also showed no effect of photoperiodic treatment on the levels of GA-like substances in root extracts. Both phloem and xylem exudates had patterns of GA-like activity similar to those found in shoots and roots, respectively. Moreover, foliar application of [3H]GA20 resulted in the transport of label from the shoot to the roots. Over half of the label in the roots represented unmetabolized [3H]GA20, indicating that part of the GA20 in the phloem is transported to the roots. Consequently, if GA20 is made in, or transported to the roots, it is rapidly metabolized in that organ. This is a clear indication that regulation of GA metabolism is greatly different in roots and shoots. 相似文献
18.
The endogenous gibberellins (GAs) from shoots of the GA-insensitive mutant,gai, ofArabidopsis thaliana were analyzed and compared with the GAs from the Landsberg erecta (Ler) line. Twenty GAs were identified in Ler plants by
full-scan gas chromatography-mass spectrometry (GC-MS) and Kovats retention indices (KRI's). These GAs are members of the
early-13-hydroxylation pathway (GA53, GA44, GA19, GA17, GA20, GA1, GA29, and GA8), the non-3,13-hydroxylation pathway (GA12, GA15, GA24, GA25, GA9, and GA51), and the early-3-hydroxylation pathway (GA37, GA27, GA36, GA13, GA4, and GA34). The same GAs, except GA53, GA44, GA37, and GA29 were detected in thegai mutant by the same methods. In addition, extracts fromgai plants contained GA41 and GA71. Both lines also contained several unknown GAs. In Ler plants these were mainly hydroxy-GA12 derivatives, whereas in thegai mutant hydroxy-GA24, hydroxy-GA25, and hydroxy-GA9 compounds were detected. Quantification of seven GAs by GC-selected ion monitoring (SIM), using internal standards, and comparisons
of the ion intensities in the SIM chromatograms of the other thirteen GAs, demonstrated that thegai mutant had reduced levels of all C20-dicarboxylic acids (GA53, GA44, GA19, GA12, GA15, GA24, GA37, GA27, and GA36). In contrast,gai plants had increased levels of C20-tricarboxylic acid GAs (GA17, GA25, and GA41) and of all C19-GAs (GA20, GA1, GA8, GA9, GA51, GA4, GA34, and GA71) except GA29. The 3β-hydroxylated GAs, GA1 and GA4, and their respective 2β-hydroxylated derivatives, GA8 and GA34, were the most abundant GAs found in shoots of thegai mutant. Thus, thegai mutation inArabidopsis results in a phenotype that resembles GA-deficient mutants, is insensitive to both applied and endogenous GAs, and contains
low levels of C20-dicarboxylic acid GAs and high levels of C19-GAs. This indicates that theGAI gene controls a step beyond the synthesis of an active GA. Thegai mutant is presumably a GA-receptor mutant or a mutant with a block in the transduction pathway between the receptor and stem
elongation.
We thank Dr. L.N. Mander, Australian National University, Canberra, for providing [2H]gibberellins, Dr. B.O. Phinney, University of California, Los Angeles, USA for [13C]GA8, and Dr. D.A. Gage, MSU-NIH Mass Spectrometry Facility (grant No. DRR00480), for advice with mass spectrometry. This work
was supported by a fellowship from the Spanish Ministry of Agriculture (I.N.I.A.) to M.T., by the U.S. Department of Energy
under Contract DE-ACO2-76ERO-1338, and by U.S. Department of Agriculture grant No. 88-37261-3434 to J.A.D.Z. 相似文献
19.
The role and source of gibberellins (GAs) involved in the development of parthenocarpic fruits of Pisum sativum L. has been investigated. Gibberellins applied to the leaf adjacent to an emasculated ovary induced parthenocarpic fruit development on intact plants. The application of gibberellic acid (GA3) had to be done within 1 d of anthesis to be fully effective and the response was concentration-dependent. Gibberellin A1 and GA3 worked equally well and GA20 was less efficient. [3H]Gibberellin A1 applied to the leaf accumulated in the ovary and the accumulation was related to the growth response. These experiments show that GA applied to the leaf in high enough concentration is translocated to the ovary. Emasculated ovaries on decapitated pea plants develop without application of growth hormones. When [3H] GA1 was applied to the leaf adjacent to the ovary a substantial amount of radioactivity accumulated in the growing shoot of intact plants. In decapitated plants, however, this radioactivity was mainly found in the ovary. There it caused growth proportional to the accumulation of CA1. Application of LAB 150978, an inhibitor of GA biosynthesis, to decapitated plants inhibited parthenocarpic fruit development and this inhibition was counteracted by the application of GA3 (either to the fruit, or the leaf adjacent to the ovary, or through the lower cut end of the stem). All evidence taken together supports the view that parthenocarpic pea fruit development on topped plants depends on the import of gibberellins or their precursors, probably from the vegetative aerial parts of the plant.Abbreviations FW
flesh weight
- GAn
gibberellin An
- HPLC
high-performance liquid chromatography 相似文献
20.
Analysis of highly purified extracts from spinach shoots by combined gas chromatography-mass spectrometry has demonstrated the presence of six 13-C-hydroxylated gibberellins (GAs): GA53, GA44, GA19, GA17, GA20, and GA29. The major GAs were GA17, GA19, and GA20, whereas the other three GAs occurred in trace amounts. Structural considerations suggest that the six GAs identified in spinach are related in the following metabolic sequence: GA53 → GA44 → GA19 → GA17 → GA20 → GA29. 相似文献