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1.
A new single gene-recessive internode length mutant inPisum, lkc, is characterized. The internodes oflkc plants are 30–40% shorter than those of comparableLkc plants, and this is attributable to reductions in both cell length and the number of cells per internode. Dwarfism in the mutant is not due to modified gibberellin (GA) levels, as determined by gas chromatography-selected ion monitoring (GC-SIM) for GA1 and GA20, and bioassay (rice cv. Tan-ginbozu). Furthermore,lkc plants are not as responsive as the wild-type to applied GA1. The diminished stature oflkc plants appears to result from a direct or indirect interference with the transduction of the GA1 signal.  相似文献   

2.
Five GAs, GA1, GA3, GA19, GA20, and GA29, were identified in extracts from mature leaf and shoot apical meristem of flowering and non-flowering sugarcane (Saccharum spp. hybrids) by combined GC/MS. The presence of ABA was also confirmed.  相似文献   

3.
Applications of various amounts of GA3 onto the shoot apex of biennial rosette-plantHyoscyamus niger L., exposed to long days and non vernalized, caused internodes formation and stem elongation. The stem length was proportional to the amount of GA3 applied. Number and length of developed internodes and the whole length of the shoot were maximal in plants treated with a greater amount of GA3. In the end, stem elongation stopped and plants formed perchedrosettes without flowering. Hence, gibberellic acid participates in mechanisms of flowering only by indirect effect on stem elongation and not directly on flower formation itself.  相似文献   

4.
The endogenous levels of gibberellins (GAs) determined by a combined HPLC-bioassay procedure and the formation ofent-kaurene, an immediate GA precursor, in cell-free extracts were studied in relation to seed development inPharbitis nil Choisy cv. Violet. Three biologically active GA fractions were obtained, tentatively identified as GA3, GA5/ GA20, and a GA fraction, possibly GA19 and/or GA44, which all increased in activity during early seed development and subsequently declined during maturation of the seeds. The total endogenous GA level reached its maximum at 19 days after anthesis, just before the seeds had attained their maximum fresh weight at about 23 days after anthesis. Similarly, theent-kaurene synthesizing capacity showed a rapid increase during the period of rapid growth of the seeds, followed by a decline during maturation. A direct relationship between the endogenous GA levels and theent-kaurene synthesizing capacity of a particular tissue was indicated.  相似文献   

5.
Several gibberellins (GAs) and kauranoids were identified in extracts of barley (Hordeum vulgare) by combined capillary gas chromatography-mass spectrometry (GC-MS). A partially purified acidic ethyl acetate extract from 21-day postanthesis developing barley grain (cv. Proctor) contained GA1 (trace), GA4 (trace), GA8 (trace), GA12, GA17, GA20 (tentative) (trace), GA25, GA34, GA48, 18-hydroxy-GA4, 12β-hydroxy-GA9, and 18-hydroxy-GA34 (tentative). A hydrolyzed butanol extract contained GA17, GA20, GA48, and 18-hydroxy-GA34 (tentative). An acidic ethyl acetate extract from 3-day-old germinating barley grain (cv. Maris Otter) contained GA1, GA3 (possibly a contaminant), GA17, GA19, GA20, GA34, GA48, and 18-hydroxy-GA34 (tentative). A hydrolyzed butanol extract contained GA34, GA48, and 18-hydroxy-GA34 (tentative). In germinating grain, levels of all GAs were very low. Two hydroxylated kauranoic acids and a number of other kauranoids were also detected in the above extracts. 1β-Hydroxylated GAs previously found in wheat were not found in barley in this study.  相似文献   

6.
[3H]GA20 (1)1, fed toVicia faba seedlings, was converted to [3H]GA20 glucosyl ester (5) and [3H]GA20-13-0-glucoside (6). The GA20 glucosyl ester (5) was identified by HPLC-RC and by GC-MS of GA20-Me formed by transesterification of (5). The [3H]GA20-Me was crystallized to constant specific radioactivity with authentic GA20-Me. On HPLC-RC the GA20-13-0-glucoside (6) was shown to have the same retention time as an authentic sample. Subsequent enzymic hydrolysis gave a product with an HPLC retention time identical to that of authentic GA20 (1).  相似文献   

7.
The gibberellin (GA) content of the reproductive organs ofCitrus sinensis (L.) Osb., cv. Bianca Comuna and the seedless variety, Salustiana, were examined by combined gas chromatography-mass spectrometry (GC/MS) at different stages of development. Gibberellins A1, A20, and A29 were identified in the reproductive buds of both cultivars 21 days prior to anthesis and in fruits 35 days after anthesis by comparison of their mass spectra and Kovats retention indices with those of standards. In addition, three uncharacterized isomers of GA1 were detected, one in buds and two in fruits. The presence of GA4 in both tissues, and of GA8 in the reproductive buds, was indicated by the occurrence of characteristic ions at the expected retention times, although their spectra were too weak for full identification. Vegetative shoots of cv. Salustiana contained gibberellins A1, A19, A20, and A29, and the unidentified isomer of GA1 present in reproductive buds. The presence of trace amounts of gibberellins A8 and A17 was also indicated. Although the two varieties did not differ qualitatively in the GAs present during flower and fruit development, the seedless variety contained slightly greater amounts. The concentrations of gibberellins A1, A4, and A20 were determined by gas chromatography-selected ion monitoring (GC/SIM) throughout ovary development and early fruit growth. In both varieties, the maximum GA1 concentration occurred at anthesis. Highest concentrations of gibberellins A20 and A4 were found in fruit 35 days after anthesis, although the GA1 concentration at this stage remained low.  相似文献   

8.
A new, single gene, recessive internode length mutant in Pisum, lkd, is described. The internodes of lkd plants are ca. 40% shorter than comparable Lkd plants and this difference appears greater in the dark than in the light. The mutant does not appear to be dwarfed due to modified gibberellin (GA) levels, as determined by gas-chromatography-selected ion monitoring (GC-SIM) for GA1 and GA20. In relative terms, the mutant responds as well as the wild-type to applied GA1. However due to its initial short stature it does not elongate to the same extent as the wild-type to high doses of GA1 suggesting that some other factor, unrelated to GA levels or perception is probably limiting growth in this mutant. Author for correspondence  相似文献   

9.
The effects of GA3, 24-epibrassinolide (EBL), and their combination on morphogenesis of Arabidopsis thaliana (L.) Heynh seven-day-old seedlings were studied. Four plant lines were analyzed: wild type Ler and ga4-1 mutant, belonging to the Landsberg erecta ecotype and wild type Col and det2 mutant, both of the Columbia ecotype. In ga4-1 and det2, GA4/1-and brassinosteroid-deficient mutants, the highest hypocotyl growth response to the lack of hormones was noted. The cotyledon shape and size were dependent on EBL, and the root length was both GA3-and EBL-regulated, indicating organ specificities in the responses to these hormones. Simultaneous treatment of dark-grown plants with GA3 and EBL exerted an additive stimulatory effect on the root growth of det2, reduced the inhibitory effect of EBL on hypocotyl elongation of ga4-1, and enhanced the effect of EBL on hypocotyl and cotyledon elongation of det2.  相似文献   

10.
Endophytes can serve as plant growth promoters as they secret a vast array of phytohormones to support host plants. Keeping the growth promoting activity of the endophytes in view, two endophytic fungi, Asprgillus fumigatus TS1 and Fusarium proliferatum BRL1 have been isolated from the roots of Oxalis corniculata. The isolates have been screened initially for growth promoting activities, including siderophores activity, phosphate solubilization, and secreation of indole acetic acid and gibberellins. Further, the isolates have assayed for the ability to promote the growth of mutant rice Waito-C. The plants associated with TS1 and BRL1 have shown higher chlorophyll content, root-shoot length, and biomass production. The growth promoting activity of the endophytes can be attributed to the various types of GAs and IAA that have been observed in the culture filtrates of the endophytes by the Gas chromatography/mass spectrometry (GC/MS). The GC/MS analysis revealed the presence of different gibberellins concentrations (ng/ml) in TS1 and BRL1 culture filtrate, i.e. GA1 (0.091?±?0.009, 0.392?±?0.007), GA3 (0.324?±?0.077, 0.089?±?0.0007) and GA7 (0.023?±?0.002, 0.492?±?0.005), respectively. Besides, a significant up regulation of plant endogenous GA1 (12.443?±?0.454 and 15.434?±?0.245) has been obsereved in TS1 and BRL1 associated plants compared to the control. Moreover, semi quantitative RT-PCR has confirmed the presence/invovment of GA pathways genes (P50–1, P450–3, P450–4, ggs2, and des). The results conclude that the endophytes isolated in this study can ably synthesize bioactive compounds, which play an important role in plant growth promotion.  相似文献   

11.
12.
Starting from the well-known conversion of exogenously applied free gibberellic acid (GA3) to its 3(O)-glucoside by intact immature fruits of runner beans (Phaseolus coccineus L.), a protein fraction has been prepared from this plant material possessing glucosylating activity towards GAs. This glucosyltransferase is located in the pericarp only and utilizes preferably UDP-glucose as a sugar donor. The product formed enzymically from GA3 and UDP-glucose could be identified by derivatization and comparison with the authentic compound to be GA3-3(O)-glucoside. Among 15 native or chemically modified GAs, the enzyme glucosylates only GA3 and to a lower extent GA7 and GA30, indicating a high enzyme specificity with regard to the A ring of gibberellins. The physiological significance of the enzymic GA3-3(O)-glucoside formation inPhaseolus coccineus is not clear, since this glucoside is not known to be endogenous in this plant. The enzyme preparation did not glucosylate substances of phenolic structure, such as hydroquinone, aesculetin, and quercetin. Glucosylation of GA3 was achieved also by enzyme preparations fromVigna sinensis and from cell suspension cultures ofDigitalis purpurea. A number of other plant materials showed no activity.  相似文献   

13.
Thele andna mutations in pea block GA biosynthesis and normally cause a marked reduction in internode length. However, neither of these genes influences the growth of plants carrying thecry s la gene combination. Plants of this genotype have long, thin internodes, pale green foliage, and abnormal flower and fruit development, collectively referred to as the slender phenotype. [13C,3H]Gibberellin A20 is metabolized to GA1, GA8, and GA29 in slender lines carrying the geneLe but only to GA29 and GA29-catabolite inle lines. Examination of12C:13C isotopic ratios showed that metabolites were strongly diluted by endogenous [12C]GAs inNa lines. However, little if any significant dilution was observed in a line homozygous for thena gene. These results confirm that thele andna mutations are fully expressed at the biochemical level in slender phenotypes of peas and concur with previous reports that internode elongation is entirely independent of GA levels incry s la (slender) plants.  相似文献   

14.
Auxin-Gibberellin Interactions in Pea: Integrating the Old with the New   总被引:4,自引:1,他引:3  
Recent findings on auxin-gibberellin interactions in pea are reviewed, and related to those from studies conducted in the 1950s and 1960s. It is now clear that in elongating internodes, auxin maintains the level of the bioactive gibberellin, GA1, by promoting GA1 biosynthesis and by inhibiting GA1 deactivation. These effects are mediated by changes in expression of key GA biosynthesis and deactivation genes. In particular, auxin promotes the step GA20 to GA1, catalyzed by a GA 3-oxidase encoded by Mendel’s LE gene. We have used the traditional system of excised stem segments, in which auxin strongly promotes elongation, to investigate the importance for growth of auxin-induced GA1. After excision, the level of GA1 in wild-type (LE) stem segments rapidly drops, but the auxin indole-3-acetic acid (IAA) prevents this decrease. The growth response to IAA was greater in internode segments from LE plants than in segments from the le-1 mutant, in which the step GA20 to GA1 is impaired. These results indicate that, at least in excised segments, auxin partly promotes elongation by increasing the content of GA1. We also confirm that excised (light-grown) segments require exogenous auxin in order to respond to GA. On the other hand, decapitated internodes typically respond strongly to GA1 application, despite being auxin-deficient. Finally, unlike the maintenance of GA1 content by auxin, other known relationships among the growth-promoting hormones auxin, brassinosteroids, and GA do not appear to involve large changes in hormone level.  相似文献   

15.
16.
Tomato (Lycopersicon esculentum Mill.) plants homozygous for the mutant pro gene, exhibiting the distinctive procera phenotype, appeared virtually identical to gibberellic acid (GA3)-treated isogenic normal plants. The pro gene and GA3 caused analogous increases in internode length, and in the length and number of cells in the outer cell layers of each internode. Internode number was also increased by pro and GA3 over the period of the experiment. Despite their greater length, the internodes of GA3-treated and pro plants reached their final size within a time period similar to that of internodes of untreated normal plants. The pro mutant itself was responsive to GA3, especially in the seedling stage, but the proportional increase in height seen in the later stages of growth was less than that of normal plants.Abbreviations GA gibberellin - GA3 gibberellic acid - LSD least significant difference  相似文献   

17.
18.
The effect of gibberellic acid (GA3) on gene expression in wheat aleurone cells has been characterised. In-vitro translation of polyadenylated RNA indicated that α-amylase and other messenger-RNA (mRNA) species increase in relative concentration in GA3-treated tissue. At least one mRNA species declines in relative level in response to GA3. There is also a GA3-dependent, four-fold increase in the level of polyadenylated RNA. This effect is largely the result of increased levels of many mRNA species which are also present in untreated tissue. Seven GA3-induced polyadenylated RNA species including the Amyl α-amylase gene product have been cloned as complementary DNA in the plasmid pBR322. These cloned DNAs have been used as hybridisation probes to show that the GA3-induced increase in α-amylase mRNA is more prolonged than the accumulation of the other GA3-regulated mRNA species. A polyadenylated-RNA sequence showing reduced concentration in GA3-treated tissue has also been cloned.  相似文献   

19.
Floral buds ofBrowallia demissa, at three stages of development, were cultured on Nitsch and Nitsch basal medium. The supplements used include IAA; several cytokinins— benzyladenine, kinetin and 6-benzyl-9 tetrahydropyran-adenine (SD 8339); gibberellic acid (GA3); 2, 3, 5-triiodobenzoic acid (TIBA); arginine and cysteine. All three stages of floral buds failed to complete development. In some treatments stages II and III produced callus and/or roots from the morphological basal end. Cytokinins promoted bud formation whereas both IAA and GA3 depressed bud formation The shoots differentiatedin vitro were capable of setting flowers, fruits and seeds in all the treatments. The seeds were viable. Comparative studies of development of flowersin vivo andin vitro were made. In some treatments the flowers exhibited abnormal corolla, and roecium and gynoecium. Factors affecting normal bud initiation, organization and development are discussed.  相似文献   

20.
A Gibberellin-Deficient Brassica Mutant-rosette   总被引:4,自引:3,他引:1  
A single-gene mutant (rosette [ros/ros]) in which shoot growth and development are inhibited was identified from a rapid cycling line of Brassica rapa (syn campestris). Relative to normal plants, the mutant germinated slowly, had delayed or incomplete floral development, and reduced leaf, petiole, and internode growth. The exogenous application of GA3 by foliar spray or directly to the shoot tip of rosette resulted in rapid flowering, bolting (shoot elongation), and viable seed production. Shoots of rosette contained endogenous levels of total gibberellin (GA)-like substances (`Tan-ginbozu' dwarf rice assay) of about one-tenth of that of the normal rapid-cycling line of B. rapa which consisted almost entirely of a very nonpolar, GA-like substance which yielded GA1 and GA3 upon mild acid hydrolysis. In a normal rapid-cycling B. rapa line, the nonpolar putative GA1 and GA3 conjugates were present, but additionally, free GA1 and GA3 were abundant and identified by gas chromatography-mass spectrometry-selected ion monitoring. The quantities of free GA1 and GA3 in the normal line and in rosette were quantified by GC-MS-SIM using [2H2]GA1 as an internal standard. Fourteen-day-old rosette and normal seedlings contained 5.3 and 23.2 ng GA1 per plant, respectively. At day 21 the rosette plants contained 7.7 and 26.1 nanograms per plant of GA1 and GA3, while normal plants contained 31.1 and 251.5 nanograms per plant, respectively. Thus, normal plants contained from four to ten times higher levels of total GA-like substances, GA1, or GA3, than rosette. The ros allele results in reduced GA level, yielding the rosette phenotype whose delayed germination and flowering, and reduced shoot growth responses indicate a probable role for endogenous GA1 and GA3 in the regulation of these processes in Brassica.  相似文献   

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