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1.
Gibberellic acid (GA3) stimulates isocitrate lyase activity of the endosperm during germination of castor bean seeds. Isocitrate lyase from castor bean was purified and an antibody to it was prepared from rabbit serum. This antibody was used to measure the amounts of isocitrate lyase-mRNA using an in vitro translation system. No specific stimulation of isocitrate lyase-mRNA by application of GA3 was detected. The stimulation of isocitrate lyase activity by exogenous GA3 may be accounted for by the action of the growth substance in advancing the overall production of rRNA and mRNA which accelerates the rate of total protein synthesis during germination. The application of Amo 1618 retards the production of isocitrate lyase activity but also retards protein synthesis in general. This suggests that endogenous gibberellins also act non-specifically in the regulation of protein synthesis during castor bean germination.Abbreviations SDS
sodium dodecyl sulphate
- GA3
gibberellic acid
- PAGE
polyacrylamide gel electrophoresis 相似文献
2.
The effect of GA3 on somatic embryogenesis from petiole fragments excised from micropropagated fennel plantlets was studied. Explants were maintained for 4 weeks on an induction medium containing, 2,4-d and kinetin and were then transferred to a medium devoid of these growth regulators to allow embryo development. The addition of autoclaved or filter-sterilized GA3 to the induction medium or to the embryo development medium increased the number of embryogenic explants. No positive effect was observed when GA3 was added to the micropropagation medium of the mother plantlets. Gibberellic acid also counteracted the inhibiting effect of continuous light on the number of embryogenic explants. Moreover, the embryogenic frequency of petiole explants from several genotypes previously considered as poorly reacting was highly enhanced by GA3.Abbreviations BA
6-benzyladenine
- 2,4-d
2,4-dichlorophenoxyacetic acid
- GA3
Gibberellic acid
- IAA
Indole-3-acetic acid
- IBA
Indole-3-butyric acid 相似文献
3.
Gibberellic acid (GA3), applied as a dispersion in aqueous lanolin to the stumps of decapitated stems of P. vulgaris plants, was found to promote the transfer of 14C-and 32P-labelled assimilates to the site of hormone application. Measurements of the component transfer processes, operating between source and sink (site of hormone application), showed that GA3 was not acting to promote assimilate transfer by increasing the photosynthetic rate of, or the assimilate export rate from the source, nor by altering the mobilizing ability of the competing root sink. Here, it also was found that the time between GA3 application and detection of an enhanced transport flux was independent of the length of the transport pathway. Overall, the evidence obtained indicated that GA3 was not acting on any transfer process remote from its point of hormone application but was acting locally at this latter point.Abbreviations GA3
gibberellic acid
- IAA
indol-3yl-acetic acid 相似文献
4.
Gibberellic acid (GA3) 20 mg 1?1 and (2-chloroethyl) phosphonic acid (Ethephon) 10 mg 1?1 enhanced pollen tube length in Crotalaria juncea L. GA3 markedly increased the activity of amylase, acid phosphatase and β-glucosidase and enhanced leaching of amylase and acid phosphatase enzymes. The rise in the activity level and leaching of amylase and acid phosphatase after Ethephon treatment was comparatively less than that of GA3 and the response to Ethephon was restricted to the 45 and 90 min period of culturing. Ethephon did not affect the activity/leaching of β-glucosidase significantly. Actinomycin-D (Act.D) 25 mg l?1 and Cycloheximide (CH) 10 mg 1?1 reduced the tube growth as well as activity of these enzymes suggesting their de novo synthesis during pollen tube growth. 相似文献
5.
Removal of stamens, or even of only the anthers, at an early stage of corolla development, before the start of main anthocyanin production, inhibited both growth and pigmentation of attached corollas of Petunia. When only one or two stamens were removed from one side, the inhibition was restricted to the corolla side adjacent to the detached stamens. Application of gibberellic acid (GA3) substituted for the stamens in its effect on both growth and pigmentation. In detached corollas, isolated at the early-green stage and grown in vitro in sucrose medium, GA3 promoted growth and was essential for anthocyanin synthesis. A marked enhancement of anthocyanin production was observed 48 h before the increase in corolla growth rate. Corollas detached at later stages were able to continue their growth and pigmentation in sucrose without GA3. When Paclobutrazol (-[(4-chlorophenyl)-ethyl]-(1,1-dimethylethyl)-H-1,2,4-triazol-1-ethanol), an inhibitor of gibberellin biosynthesis, was added to the growth medium of in-vitro-grown corollas, pigmentation was inhibited but there was no effect on corolla growth. Low levels of GA3 counteracted the Paclobutrazol effect on pigmentation but did not affect growth. The above results indicate that the effect of GA3 (and probably that of the stamens) on corolla growth is independent of its effect on pigmentation. Gibberellic acid and paclobutrazol had no effect on [14C]sucrose uptake by in-vitro-grown corollas. The activity of phenylalanine ammonialyase was correlated with the effect of stamens and GA3 on pigmentation in corollas grown in vivo and in vitro.Abbreviations GA
gibberellin
- GA3
gibberellic acid
- PAC
Paclobutrazol
- PAL
phenylalanine ammonia-lyase 相似文献
6.
The white-light-(WL) induced enlargement of dicotyledonous leaf cells is known to occur via an acid-growth mechanism; i.e., WL causes leaf cells to excrete protons which lead to an increase in wall extensibility and thus cell enlargement. Gibberellic acid (GA3) and N6-benzyladenine (BA) also induce leaf cell enlargement. To see if they also act via acid-induced cell wall loosening, a comparison has been made of WL-, GA3-and BA-induced growth of strips, taken from primary leaves of bean (Phaseolus vulgaris L.) plants raised in continuous red light for 10 d. White light, GA3 and BA all increased wall extensibility as measured by the Instron technique, and this change preceded the increase in growth rate. However, whereas WL induced significant proton excretion, neither GA3 nor BA caused any acidification of the apoplast. Furthermore, neutral buffers, which effectively inhibited the growth induced by WL, were without effect on growth promoted by either GA3 or BA. These results indicate that while WL, GA3 and BA all initiate growth in bean leaves by altering cell-wall properties, GA3 and BA do so through some wall loosening mechanism other than wall acidification. Neither gibberellin nor cytokinin is likely to play a major role in light-induced cell enlargement of dicotyledonous leaves.Abbreviations BA
No-benzyladenine
- FC
fusicoccin
- GA3
gibberellic acid
- RL
red light
- SK medium
10 mM sucrose+10mM KCl
- WL
white light 相似文献
7.
Gibberellic acid (GA3) inhibits amaranthin synthesis whereas the growth retardant, phosphon D, enhances pigment levels in A. caudatus seedlings exposed to light. No effect was observed on chlorophyll and carotenoid synthesis. Radioactive tyrosine and DOPA were incorporated into amaranthin. The specific activity of amaranthin synthesised in the presence of 14C-tyrosine or 14C-DOPA in seedlings treated with GA3 is higher than water controls. The specific activity of pigment from phosphon D treated tissue is relatively low. GA3 treated tissue has lower active tyrosine and DOPA pools compared to phosphon treated seedlings. Tyrosine and DOPA-oxidase activity increases in GA3 treated and H2O control seedlings exposed to light. Kinetin stimulates the synthesis of amaranthin in dark-grown seedlings and this is not overcome by simultaneous GA3 application. Dark-grown seedlings treated with different kinetin concentrations and incubated in 14C-tyrosine synthesise radioactive amaranthin of similar specific activity. Kinetin treatment of dark-grown seedlings brings about an increased tyrosine and DOPA-oxidase activity. The results indicate that GA3 controls the production and/or availability of tyrosine whereas kinetin can mimic light treatment and controls the utilisation of tyrosine probably by bringing about the synthesis or activation of tyrosine and DOPA-oxidase protein. 相似文献
8.
Indole-3-acetic acid (IAA) strongly enhanced rooting of etiolated pea epicotyl cuttings while gibberellic acid (GA3) enhanced rooting only slightly. The promoting effects of the hormones appeared not until 14 d after the onset of treatment. When GA3 and IAA were applied together, the initiation of rooting started already after 6 d after onset of treatment. It is suggested that gibberellin plays an important role, in combination with auxin, in the initiation of root formation in Pisum cuttings.Abbreviations IAA
Indole-3-acetic acid
- GA3
Gibberellic acid 相似文献
9.
In an early-flowering line of pea (G2) apical senescence occurs only in long days (LD), while growth in short days (SD) is indeterminate. In SD, G2 plants are known to produce a graft-transmissible substance which delays apical senescence in related lines that are photoperiod-insensitive with regard to apical senescence. Gibberellic acid (GA3) applied to the apical bud of G2 plants in LD delayed apical senescence indefinitely, while N6-benzyladenine and -naphthaleneacetic acid were ineffective. Of the gibberellins native to pea, GA9 had no effect whereas GA20 had a moderate senescence-delaying effect. [3H]GA9 metabolism in intact leaves of G2 plants was inhibited by LD and was restored by placing the plants back in SD. Leaves of photoperiod-insensitive lines (I-types) metabolized GA9 readily regardless of photoperiod, but the metabolites differed qualitatively from those in G2 leaves. A polar GA9 metabolite, GAE, was found only in G2 plants in SD. The level of GA-like substances in methanol extracts from G2 plants dropped about 10-fold after the plants were moved from SD to LD; it was restored by transferring the plants back to SD. A polar zone of these GA-like materials co-chromatographed with GAE. It is suggested that a polar gibberellin is synthesized by G2 plants in SD; this gibberellin promotes shoot growth and meristematic activity in the shoot apex, preventing senescence.Abbreviations GA
gibberellin
- GA3
gibberellic acid
- SD
short days
- LD
long days 相似文献
10.
The Effect of Gibberellin on Tryptophan Conversion and Elongation of the Avena Coleoptile 总被引:1,自引:0,他引:1
Gibberellic acid (GA3) enhanced directly the release of 14CO2 from tryptophan-1-l4C by cell free preparations of Avena coleoptile tips. The rate of tryptophan metabolism in the presence of GA3 was increased by approximately 100 per cent. The addition of auxin synthesis inhibitors to incubation flasks nullified the enhancement effect of GA3 on elongation of the coleoptile tips. These studies implicate tryptamine as an intermediate in the formation of auxin from tryptophan. The possibility of GA3-IAA interaction in the elongation processes was also investigated. Combination treatments of these growth-promoting substances did not induce a synergistic growth response by the coleoptile tissue. 相似文献
11.
When callus cells of Daucus carota are grown on a medium containing gibberellic acid (GA3) in a physiological concentration of 3x10-6 M the cells cease to accumulate anthocyanins. This anthocyanin-free cell line has a very low activity of phenylalanine ammonia-lyase. After density labelling with D2O an intensive de novo synthesis of the phenylalanine ammonia-lyase (E.C. 4.3.1.5; PAL) in the anthocyanin-containing cells does occur. 58% of the C-bound H-atoms are replaced by deuterium. The anthocyanin-free cells show only a very low enzyme synthesis which is difficult to detect with density labelling experiments. To ascertain that de novo synthesis occurs in the anthocyanin-free cells, the incorporation of 14C-labelled amino acids into the partially purified enzyme protein was measured after separation of the protein a) in CsCl gradients and b) on polyacrylamide gels. In both cases the enzyme bears 14C-label. These results suggest that in the anthocyanin-free cells de novo synthesis of PAL is still occuring but the synthesis is reduced in comparison to the anthocyanin-containing cells.Abbreviations GA3
gibberellic acid
- PAL
phenylalanine ammonia-lyase (E.C.4.3.1.5)
- DCb
anthocyanin-containing cells
- DCw
anthocyanin-free cells 相似文献
12.
Indole-3-acetic acid (IAA), fusicoccin and weak acids all lower the cytoplasmic pH (pHi) and induce elongation growth of maize (Zea mays L.) coleoptiles. Gibberellic acid (GA3) also induces elongation growth and we have used confocal laser scanning microscopy to study the effects of GA3 on pHi employing the pH-indicator dyes, 2,7-bis(2-carboxyethyl)-5-(and-6) carboxyfluorescein and carboxy-semi-naphthorhodafluor-1. We confirm that GA3 induces growth significantly in light-grown but only slightly or not at all in dark-grown coleoptiles. The growth induced by IAA treatment was similar in light- and dark-grown coleoptiles. The pHi decreased by up to 0.6 units during the first 7 min of GA3 or IAA treatment of both light- and dark-grown coleoptiles. Gibberellic acid inhibited IAA-induced growth of dark-grown coleoptiles. Hence, in dark-grown coleoptiles GA3 may activate either directly or indirectly reactions that interfere with the signalling pathway leading to elongation growth. The possible role of pHi in growth is discussed.Abbreviations ABA
abscisic acid
- AM
acetoxymethyl ester
- BCECF
2,7-bis(2-carboxyethyl)-5-(and-6) carboxyfluorescein
- [Ca2+]i
cytoplasmic free calcium
- GA(n)
gibberellin A(n)
- GA3
gibberellic acid
- IAA
indole-3-acetic acid
- PGR
plant growth regulator
- pHi
cytoplasmic pH
- Pipes
piperazine-N,N-bis[2-ethanesulfonic acid]
- Snarf-1
carboxy-semi-naphthorhodafluor-1
We thank Dr R. King (CSIRO, Canberra) for providing the GA1 and T. Phillips for processing the photographic material. H.R. Irving was supported by an Australian Research Council Research Fellowship and the work was supported by an Australian Research Council grant. 相似文献
13.
A highly sensitive and specific radioimmunoassay which allows the detection of as little as 5 fmol (2 pg) of gibberellic acid (GA3) in crude plant extracts is described. Antisera of high affinity and titer were obtained by immunizing rabbits with a conjugate of carboxyl-coupled GA3 and bovine serum albumin. [125I]Gibberellic acid-[N-(p-hydroxybenzyl) putrescine]amide of high specific activity, used as the immunotracer, is readily displaced by gibberellic acid methyl ester but not by free gibberellic acid. Thus, methylation of extracts prior to analysis is required. The assay is very specific; besides GA3, only the closely related GA7 is highly immunoreactive. Various gibberellins, related compounds, as well as other classes of plant hormones do not interfere with the assay. Levels of immunoreactive gibberellins (GA3, GA7) in actively growing tissues, among them cell suspension cultures of 33 different species, were determined.Abbreviations ABA
abscisic acid
- GC-MS
gas chromatography-mass spectroscopy
- TLC
thin-layer chromatography
- GA
gibberellin
Part 17 in the Series: Use of Immunoassay in Plant Science 相似文献
14.
The effect of gibberellic acid (GA3) on ion ratios in a dwarf maize mutant (Zea mays L. d1) exhibiting normal growth after hormone treatment has been investigated by electron microprobe analysis. Gibberellic-acid treatment increased the ion content in chloroplasts and vacuoles whereas no change of the ion content was found in the cytoplasm. The relation of these observations to the action of the hormone is discussed.Abbreviation GA3
Gibberellic acid 相似文献
15.
As part of our investigation of the mode of action of plant hormones in barley (Hordeum vulgare L.) aleurone layers, we have studied the expression of five identified and three unidentified mRNA species in the presence of exogenous gibberellic acid (GA3) and abscisic acid. Three of the mRNAs are GA3-inducible, three are suppressed by GA3, and two are constitutive. The extent of the GA3 effect differs considerably for both inducible and suppressible mRNAs. For example, a ten-fold higher concentration of GA3 (10-8 M) is required for full induction of the high-pl group -amylase mRNA than is required for the low-pI -amylase mRNA (10-9 M). Temporal regulation of mRNA abundance also varies between the two -amylase isoenzyme groups. The three GA3-suppressible mRNA species studied, alcohol dehydrogenase (ADH1), a probable amylase and protease inhibitor, and an unidentified barley mRNA species also varied in response to GA3. The ADH1 mRNA decreased drastically within 8 h of GA3 treatment, whereas the other two began to decrease in abundance only after 12–16 h of GA3 treatment. Abscisic-acid treatment counteracted the GA3 effects for both the inducible and suppressible mRNA species. Comparison of -amylase-mRNA levels and -amylase-synthesis rates showed a strong correlation between the two parameters, the only exception being a lack of -amylase synthesis in the presence of -amylase mRNA at low GA3 concentrations. Therefore, the expression of -amylase seems to be regulated primarily by its mRNA levels.Abbreviations ABA
abscisic acid
- ADH1
alcohol dehydrogenase 1
- cDNA
copy DNA
- GA3
gibberellic acid
- PAPI
probable amylase/protease inhibitor 相似文献
16.
17.
The insoluble cell wall polymers of cultured spinach cells contained esterified ferulic acid at 2–5 mg g-1 dry weight. Gibberellic acid (GA3, 10-11–10-6 M) promoted the expansion of these cells and simultaneoulsy suppressed peroxidase secretion, reduced the activity of cellular phenylanine ammonia-lyase and favoured the accumulation of wall-esterified ferulate and of extracellular soluble phenolic aglycones. When growth was prevented with 0·7 M sorbitol, GA3 still evoked the phenolic and peroxidase effects. It is suggested that peroxidase restricts growth by rigidifying the cell wall in two ways: (a) covalently by catalysing the conversion of feruloyl side-chains into diferuloyl cross-links and (b) non-covalently by catalysing the conversion of soluble phenolics into hydrophobic quinones (or polymers). GA3 is hypothesised to prevent this rigidification by inhibiting peroxidase secretion.Abbreviations
A
28
absorbance at 280 nm
-
a
1cnt
1%
absorptivity coefficient
- 2,4-D
2,4-dichlorophenoxyacetic acid
- EtOAc
ethylacetate
- GA3
gibberellic acid
- mol wt
molecular weight
- PAL
phenylalanine ammonia-lyase
- PCV
packed cell volume
- sh
shoulder or inflection
- TLC
thin-layer chromatography
- UV
ultra-violet
-
wavelength
- IAA
indoleacetic acid 相似文献
18.
Shubhada Thengane S. V. Paranjpe S. S. Khuspe A. F. Mascarenhas 《Plant Cell, Tissue and Organ Culture》1986,6(3):209-219
An interspecific hybrid of the sexually incompatible species G. hirsutum cv. Laxmi and G. arboreum cv. Jyoti was obtained through in ovulo embryo culture. Eightto twelve-day-old ovules were excised and cultured on Beasley and Ting's medium supplemented with Indol-3 acetic acid (5×10-6 to 7×10-6 M), Kinetin (5×10-6 to 5×10-8 M), Gibberellic acid (5×10-7 to 5×10-9M), Ammonium chloride (5 to 15mM) and Casein hydrolysate (50 to 200mg/l) added individually and in various combinations along with sucrose. No single medium was adequate to ensure complete development of the fertilized ovules to plantlets, thus necessitating a sequential five step transfer to different media. Cytological studies confirmed the hybrid nature of the plants.Abbreviation IAA
Indol-3 acetic acid
- Kn
Kinetin
- GA3
Gibberellic acid
- CH
Casein hydrolysate
- NAA
-Naphthalene-acetic acid
- BT
Beasley and Ting's basal medium
- MS
Murashige and Skoog's basal medium
- W
White's basal medium
NCL Communication number 3823. 相似文献
19.
Gibberellic acid (GA3) is a very potent hormone whose natural occurrence in plants controls their development. Cadmium is a particularly dangerous
pollutant due to its high toxicity and great solubility in water. In this study, the effect of GA3 on Allium sativum root tip cells was investigated in the presence of cadmium. A. sativum root tip cells were exposed to CdNO3 (50, 100, 200 μM), GA3 (10-3 M), both CdNO3 and GA3. Cytogenetic analyses were performed as micronucleus (MN) assay and mitotic index (MI). Lipid peroxidation analysis was also
performed in A. sativum root tip cells for determination of membrane damage. MN exhibited a dose-dependent increase in Cd treatments in A. sativum. GA3 significantly reduced the effect of Cd on the MN frequency. MN was observed in GA3 and GA3 + 50 μm Cd treatments at very low frequency. MI slightly decreased in GA3 and GA3 + Cd treatments. MI decreased more in high concentrations of Cd than combined GA3 + Cd treatments. The high concentrations of cadmium induce MN, lipid peroxidation and lead to genotoxicity in A. sativum. Current work reveals that the effect of Cd on genotoxicity can be partially restored with GA3 application. 相似文献
20.
Aeration of carrot storage tissue disks in water was accompanied by net folate synthesis and by changes in the specific activities of key folate-dependent enzymes. Disks aerated in 0.1 mM gibberellic acid (GA3) for 48 hr contained higher concentrations of methyltetrahydrofolates but aeration in 5 mM L-methionine reduced net folate synthesis. Gibberellic acid also increased the specific activities of 5,10-methylenetetrahydrofolate reductase (E.C. 1.1.1.68), serine hydroxymethyltransferase (E.C. 2.1.2.1) and 5-methyltetrahydrofolate: homocysteine transmethylase. The levels of these enzymes in disks aerated in L-methionine (5 mM) were comparable or slightly higher than those of disks aerated in water. Activity of the reductase and 10-formyltetrahydrofolate synthetase (E.C. 6.3.4.3) was inhibited by L-methionine in vitro. Aeration increased ability to incorporate formate [14C] into serine, glycine and methionine. Disks aerated for 36 hr in 0.1 mM GA3 incorporated greater amounts of 14C into free methionine but those aerated in L-methionine (5 mM) had less ability to metabolize formate and the specific radioactivities of free glycine, serine and methionine were low. 相似文献