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1.
In the temperate-zone woody species Salix pentandra elongation growth is regulated by the photoperiod. Long days sustain active growth, whereas short days induce cessation of apical growth, which is a prerequisite for winter hardening. It is shown that this is correlated to quantitative changes in levels of endogenous GA19 GA20 , and GA1 . Within two short days the amount of the active GA1 and its immediate precursor GA20 , decreased markedly in young leaves us well as in stem tissue. Also, the amount of GA19 , declined, but the decrease was delayed relative to that of GA1 and GA20 . The ability of S. pentandra seedlings to respond to exogenous GA19 , decreased with increasing numbers of short days. Observations that support the hypothesis that the level of GA1 in S. pentandra is regulated by the photoperiod in a quantitative mode with conversion of GA19 , to GA20 , being one target for control.
Different distribution of GAs in various plant parts was observed. The level of GA was higher in young leaves than in other plant parts, and the amount of GA19 was 5–10 times higher in stem tissue than in leaves and roots. The ratios of GA8 to GA1 and GA20 , were higher in roots as compared with other parts, as rods contained very low levels of GA1 and GA20 , but amounts of GA20 comparable with other parts. 相似文献
Different distribution of GAs in various plant parts was observed. The level of GA was higher in young leaves than in other plant parts, and the amount of GA
2.
Effects of exogenous gibberellins GA53 , GA44 , GA19 , GA20 and GA1 on photoperiodically controlled shoot elongation in seedlings of Salix pentandra L. were studied. Gibberellins GA20 and GA1 induced shoot elongation under short days (SD) and could substitute for a transfer to long day (LD), while gibberellins A53 , A44 and A19 were inactive. In seedlings exposed to a prolonged SD-treatment (30 days) there was a significant positive interaction between a transfer to LD and a treatment with GA20 and GA1 on shoot elongation. In addition, GA19 enhanced the growth promotive effect of LD in these seedlings. The results are compatible with the suggestion that conversion of GA19 to GA20 is blocked under SD. This effect is supposed to be an early process leading to the cessation of shoot elongation under SD. Responsiveness of the seedlings to LD and to a GA-treatment gradually decreased with an increasing length of exposure to SD. 相似文献
3.
Effects of gibberellins A1 , A4/7 , A9 , A19 and A20 and growth retardants were studied on shoot elongation in seedlings of Salix pentandra L. The growth-retarding effects of CCC and ancymidol were antagonized by all the gibberellins tested. The novel plant growth regulator prohexadione (free acid of BX-112), which is suggested to block 3β-hydroxylation of gibberellins, effectively prevented shoot elongation in seedlings grown under long photoperiod. Initiation of new leaves was only slightly reduced. GA1 , but not GA19 and GA20 , was active in overcoming the inhibition of stem elongation of seedlings, treated with prohexadione, GA19 , GA20 and GA1 are native in S. pentandra , and the results are compatible with the hypothesis that GA1 is active per se in shoot elongation, and that the effect of GA19 and GA20 is dependent on their conversion to GA1 .
A mixture of GA4 and GA7 was as active as GA1 in promoting shoot elongation in seedlings treated with prohexadione, while GA9 showed slight activity only when applied at high doses. 相似文献
A mixture of GA
4.
Growth-promoting activity of gibberellins on shoot elongation in Salix pentandra is reduced by 16,17-dihydro derivatisation 总被引:1,自引:0,他引:1
The metabolism of GA10 is thought to be under photoperiodic control in the woody plant Salix pentandra . However, in a recent study using 16,17-[3 H2 ]GA19 as a mimic of Ga10 , no effect of photoperiod was found on its metabolism to 16,17-dihydro-GA20 and 16,17-dihydro-GA1 . To investigate if this was due to differential action of exogenous 16,17-dihydro-GAs and GAs, the effects of the 16,17-dihydro-derivatives of the gibberellins GA19 , GA1 , and GA1 as compared with their parent GAs, on shoot elongation in seedlings of S. pentandra were studied. 16,17-Dihydro-GA19 , and -GA20 were both almost inactive, while 16,17-dihydro-GA1 induced some shoot elongation in seedlings treated with ancymidol as well as under short days. GA19 , GA20 and GA1 were all able to counteract the inhibitory effect of ancymidol under continuous light, while inhibition induced by a 12-h photoperiod was antagonised only by GA20 and GA1 . Thus, the growth-stimulating activity of the tested GAs is significantly reduced by 16,17-dihydro derivatisation, but the derivatives do not inhibit stem elongation in S, pentandra , as has been found in monocotyledons. 相似文献
5.
Three-week-old shoots of the spring oilseed rape cv. Petranova ( Brassica napus L. ssp. napus ) were found by combined gas chromatography-mass spectrometry to contain GA1 , GA8 , GA15 , GA17 , GA19 , GA20 , GA24 , GA29 , 3-epi-GA1 and a previously uncharacterised C19 dicarboxylic acid that is probably structurally related to GA24 . Shoots of the winter cultivar Belinda, harvested at the early flowering stage, contained the same GAs with the exception of the C19 dicarboxylic acid and, in addition, GA34 and GA51 were identified. All material contained higher levels of GA20 than of GA1 ; the ratio of GA1 to GA20 was highest in shoots containing the largest proportion of young immature tissues. Soil treatment of cv. Petranova seedlings with the growth retardant BAS 111¨W [1-phenoxy-5,5-dimethyl-3-(1,2,4-triazol-1-yl)-hexan-4-ol] caused 80% reduction in height 18 days after treatment and the levels of all GAs were 20% or less that of control plants. Foliar treatment at the same dosage reduced height by 50% and caused an 85% or greater reduction in the concentrations of the GA1 precursors GA20 , GA19 and GA44 . However, the levels of GA1 , GA8 and GA29 were affected to a much smaller extent. Foliar application of BAS 111¨W to cv. Belinda 1 month after sowing resulted in only a 20% height reduction at flowering, but no uniform decrease in the concentrations of endogenous GAs at this stage. 相似文献
6.
By application of a recently developed method allowing analysis of gibberellins (GAs) in mg amounts of tissue, the effect of photoperiod on levels of GAs in shoot tips of individual seedlings of the woody species Salix pentandra was studied. In elongating long day-grown seedlings, maximum levels of GA1 were found 5–20 mm below the apex, approximately twice the levels in other segments. After exposure of plants to 5 or 15 short days, the levels of GA1 were about 50% lower within this specific region of the stem, as compared with seedlings grown under long days. Short day-induced cessation of shoot elongation also correlated with overall declines in the levels of GA53 , GA19 , GA20 and GA8 , Within each photoperiodic treatment the levels of these GAs were generally relatively similar throughout the upper 35 mm of stems. No differences in internode lengths or in lengths of pith or epidermal cells were found in plants grown under long days compared with those exposed to 5 short days. In both cases, cells in mitosis were observed in the subapical stem tissues of shoot tips. After 15 short days, stem elongation was completed, and dividing cells were generally not found in the subapical part of the stem. However, short day exposure did not prevent elongation of internodes and cells differentiated before the treatment was started. Thus, the localised decrease in level of GA1 in shoot tips under short days precedes the morphological and anatomical changes connected with the short day-induced cessation of elongation growth. This supports the hypothesised role for GA1 in photoperiodic control of shoot elongation in S. pentandra . 相似文献
7.
8.
Endogenous gibberellins (GAs) were extracted and purified from apical buds of Eucalyptus nitens (Deane and Maid.) Maid. and the cambial region of E. globulus (Labill.). then analysed by capillary gas chromatography-mass spectrometry. GA1 GA19 GA20 and GA29 were identified by full scan mass spectra. Kovats retention indices and high resolution selected ion monitoring. Using deuterated internal standards. GA1 . GA19 . GA20 and putative GA29 and GA53 were quantified in the apical buds, while GA4 . GA8 . GA9 and GA44 were shown to be either absent or present at very low levels. From the cambial region. GA1 and GA20 were quantified at levels of 0.30 ng (g fresh weight)-1 and 8.8 ng (g fresh weight)-1 respectively. These data suggest that the early 13-hydroxylation pathway is the dominant pathway for GA biosynthesis in Eucalyptus . 相似文献
9.
The extreme dwarf d x tomato ( Lycopersicon esculentum Mill.) mutant has very short internodes which were found to contain shorter and fewer epidermal cells. The leaves are highly abnormal. The mutant showed a substantial stem growth response to GA3 , without approaching normal stature or morphology. The active gibberellin GA1 and its precursors GA19 and GA20 were identified by coupled gas chromatography-mass spectrometry (GC/MS) in d x shoots. Quantitative GC/MS revealed that GA20 accumulated to far higher levels than normal in stems and leaves of the mutant. 相似文献
10.
Olavi Junttila 《Physiologia plantarum》1981,53(3):315-318
Fifteen different gibberellins (GA's) were tested for their ability to induce elongation growth under short day conditions in seedlings of Salix pentandra L. GA's were applied either to the apex or they were injected into a mature leaf. GA3 was highly active and also GA4+7 and GA4 showed high activity. GA1 , GA2 , GA5 , GA9 , GA13 , GA20 , GA36 and GA47 showed moderate activity. GA16 , GA17 , GA27 and GA41 exhibited low or no activity in doses up to 10 μg per plant. In general, a better growth response was obtained with an application to the apex than with an injection into the leaf. 相似文献
11.
Evidence was obtained by gas chromatography-mass spectrometry and gas chromatography-selected ion monitoring for the presence of gibberellin A20 ), GA1 , GA29 , GA8 and 2-epiGA29 in vegetative shoots of tall sweet pea, Lathyrus odoratus L. Both tall (genotype L –) and dwarf (genotype II ) sweet peas elongated markedly in response to exogenous GA1 attaining similar internode lengths at the highest dose levels. Likewise internode length in both genotypes was reduced by application of the GA biosynthesis inhibitor, PP333. The ratio of leaflet length to width was reduced by application of PP333 to tall plants and this effect was reversed by GA1 . When applied to plants previously treated with PP333, GA20 promoted internode elongation of L – plants as effectively as GA1 , but GA29 was not as effective as GA1 when applied to II plants. In contrast, GA20 and GA1 were equally effective when applied to the semidwarf lb mutant but GA-treated lblb plants did not attain the same internode length as comparable GA-treated Lb – plants. The difference in stature between the tall and dwarf types persisted in dark-grown plants. It is concluded that GA1 may be important for internode elongation and leaf growth in sweet pea. Mutant l may influence GA1 synthesis by reducing 3β-hydroxylation of GA20 whereas mutant lb appears to affect GA sensitivity. 相似文献
12.
T. Moritz 《Physiologia plantarum》1995,95(1):67-72
Short photoperiod induces growth cessation in seedlings of Norway spruce ( Picea abies (L.] Karst.). Application of different gibberellins (GAS) to seedlings growing under a short photoperiod show that GA9 and GA20 can not induce growth. In contrast application of GA, and GA4 induced shoot elongation. The results indicate that 3β-hydroxylation of GA9 to GA4 and of GA20 to GA1 is under photoperiodic control. To confirm that conclusion, both qualitative and quantitative analyses of endogenous GAs were performed. GA1 , GA3 , GA4 , GA7 , GA9 , GA12 , GA15 , GA15 , GA20 , GA29 , GA34 and GA51 were identified by combined gas chromatography-mass spectrometry in shoots of Norway spruce seedlings. The effect of photoperiod on GA levels was determined by using deuterated and 14 C-labelled GAs as intermal standards. In short days, the amounts of GA9 , GA4 and GA1 are less than in plants grown in continuous light. There is no significant difference in the amounts of GA3 , GA12 , and GA20 between the different photoperiods. The lack of accumulation of GA9 and GA20 under short days is discussed. 相似文献
13.
GA1 , GA8 , GA17 , GA19 , GA20 and GA29 were identified by combined gas chromatography-mass spectrometgry (GC-MS) in immature seeds and pericarp of Lycopersicon esculentum Mill. (tomato). Higher levels of these GAs were present in the seeds than in the pericarp; seeds in addition contained GA15 , GA24 , GA25 , and GA44 . Fruits of the Lycopersicon pimpinellifolium Mill. mutant I were smaller and contained lower GA1 concentrations, but higher GA20 concentrations, than those of mutants III and IV. In contrast, differences in fruit size in L. esculentum due to position on the truss did not correlate with GA1 concentration in either the pericarp or seeds. 相似文献
14.
Jaime F. Martínez-García Cristina M. Santes José L. García-Martínez 《Physiologia plantarum》2000,108(4):426-434
It has been shown previously that gibberellins (GAs) mediate the phytochrome (Phy) control of cowpea ( Vigna sinensis L.) epicotyl elongation induced by end-of-day (EOD)-far-red light (FR). In the present work, the EOD-FR effect on GA metabolism and GA levels in cowpea has been investigated. GA1 , GA8 , GA19 and GA20 were identified in epicotyls, and GA1 , GA19 , GA20 and GA29 -catabolite in leaves of 6-day-old cowpea seedlings. The content of GA1 in the epicotyl paralleled the decrease of its growth rate, supporting the hypothesis that this is the GA bioactive in controlling cowpea epicotyl elongation. FR enhanced both the amount of [3H]GA1 in the epicotyl produced from applied [3H]GA20 , and that of applied [3H]GA1 that remained unmetabolized in epicotyl explants, suggesting that Phy may regulate the inactivation of GA1 . In agreement with this effect of light on GA1 metabolism, the contents of GA1 in the epicotyl remained higher in FR-treated than in R-treated explants. Moreover, in intact seedlings EOD-FR treatment increased both epicotyl elongation and GA1 content in the responsive epicotyl, whereas it was not altered in the leaves. These results show, for the first time, that photostable Phys modulate the stem elongation in light-grown plants by locally controlling the GA1 levels through regulation of its inactivation. 相似文献
15.
The highly active, polar gibberellin-like substance found in the apical region of shoots of tall (genotype Le ) peas ( Pisum sativum L.) is shown by combined gas chromatography-mass spectrometry (GC/MS) to be GA1 . This substance is either absent or present at only low levels in dwarf ( le ) plants. Multiple ion monitoring (MIM) tentatively suggests that GA8 may also be present in shoot tissue of tall peas. Gibberellin A1 is the first 3 β-hydroxylated gibberellin positively identified in peas, and its presence in shoot tissue demonstrates the organ specificity of gibberellin production since GA1 has not been detected in developing seeds. Application of GA1 can mask the Le/le gene difference. However, whilst Le plants respond equally to GA20 and GA1 , le plants respond only weakly to GA20 , the major biologically active gibberellin found in dwarf peas. These results suggest that the Le gene controls the production of a 3 β-hydroxylase capable of converting GA20 to GA1 . Further support for this view comes from feeds of [3 H] GA20 to Le and le plants. Plants with Le metabolise [3 H] GA20 to three major products whilst le plants produce only one major product after the same time. The metabolite common to Le and le plants co-chromatographs with GA29 . The additional two metabolites in Le peas co-chromatograph with GA1 and GA8 . 相似文献
16.
Endogenous gibberellins (GAs) in corms of Polianthes tuberosa L. (cv. Double) were isolated and identified by high performance liquid chromatography, bioassay and combined capillary gas chromatography-mass spectrometry (GC-MS). Gibberellins A1 , A19 , A20 and A53 were quantified at the vegetative, early floral initiation and flower development stages. The identification of 13-hydroxylated GAs indicates the presence of the early 13-hydroxylation pathway in P. tuberosa corms. An increase in GA1 and GA20 , and a decrease in GA19 levels, coincided with the transition from the vegetative phase to the stages of early floral initiation and flower development. GA53 stayed at constant levels at the 3 different growth stages. The absence of GA1 in vegetative corms and its presence in corms at early floral initiation and flower development stages suggest that GA1 is a causal factor in inducing floral initiation in P. tuberosa . When GA1 , GA3 , GA4 , GA20 and GA32 were applied to corms at the vegetative stage (plants about 5 cm in height), floral initiation was promoted by all of the GAs used, GA32 being the most active. In contrast with the other GAs, GA32 had no effect on stem elongation. Therefore, it is suggested that hydroxylated C-19 GAs play an important role in flower induction in P. tuberosa . 相似文献
17.
Avihai Ilan Karen P. Zanewich Stewart B. Rood Donald K. Dougall 《Physiologia plantarum》1994,92(1):47-52
Gibberellic acid (GA3 ) applied at different times during the growth of wild carrot ( Daucus carota ssp. Carota ) cell suspension cultures inhibited anthocyanin accumulation. Application of 3 × 10–6 M GA3 to cultures on day 0 or day 4 gave, respectively, 10 or 35% of anthocyanin accumulation relative to levels occurring when GA3 was applied at the end of the growth period. Endogenous GAs were separated by high pressure liquid chromatography, and identified and quantified by gas chromatography-selected ion monitoring. Gibberellins GA1 , GA3 and traces of GA8 . GA19 and GA20 were identified in carrot cell suspension cultures of both high and low anthocyanin-accumulating clones. The concentrations of GA1 . GA3 and GA8 in the two clones were similar and were not significantly different after the application of uniconazole which promoted anthocyanin accumulation. This suggests that these endogenous GAs are not the sole factors controlling the accumulation of anthocyanin in these different clones. Exogenous GA3 and uniconazole had no effect on 3'-nucleotidase and 5'-nucleotidase activity in the carrot cell suspension cultures. Thus 3'-nucleotidase does not appear to play a role in the inhibition of anthocyanin accumulation by exogenous GA3 . 相似文献
18.
Olavi Junttila Einar Jensen David W. Pearce Richard P. Pharis 《Physiologia plantarum》1992,84(1):113-120
Cessation of shoot elongation in seedlings of Salix pentandra L. is induced by short photoperiod. Gibbereliin A9 (GA9 ) applied either to the apical bud or injected into a mature leaf, induced shoot elongation under a short photoperiod of 12 h, and GA9 could completely substitute for a transfer to a long photoperiod. When [3 H]GA9 or [2 H2 ]GA9 was injected into a leaf, no [3 H]GA9 was detected in the elongating apex and only traces of [3 H]GA9 were found in the shoot above the treated leaf. By the use of gas chromatography-mass spectrometry (GC-MS), [2 H2 ]GA20 was identified as the main metabolite of [2 H2 ]GA9 in both the shoot and the treated leaf. In addition, [2 H2 ]GA1 and [2 H2 ]GA29 were also identified as metabolites of [2 H2 ]GA9 . These results are consistent with the hypothesis that exogenous GA, promotes shoot elongation in Salix through its metabolism to GA20 and GA,. 相似文献
19.
Alasdair K. MacKenzieHose Leanne J. Sherriff John J. Ross James B. Reid 《Physiologia plantarum》1998,103(4):485-490
We describe a new mutation, lrs , which reduces internode length in Pisum sativum L. The mutation appears to act by reducing both GA synthesis and the response to GA1 . The levels of the 13‐hydroxylated GAs, GA53 , GA44 , GA19 , GA20 , GA1 , and GA8 in the lrs mutant were greatly reduced compared with the wild‐type. The extent of the reduction in GA1 content in the apical tissues would, at least in part, account for the dwarf phenotype of the mutant. The reduced GA responsiveness of the new mutant was indicated by the inability of applied GA1 to remove the difference in elongation between lrs and LRS plants. The lrs mutant appears to be unique amongst internode length genotypes, possessing characteristics of both GA synthesis and GA response mutants. 相似文献
20.
After the application of [13 C3 H]-gibberellin A20 to wild-type (tall) sweet peas ( Lathyrus odoratus L.) labelled gibberellin A1 (GA1 ), GA8 , GA29 and 2-epiGA29 were identified as major metabolities by gas chromatography-mass spectrometry after high performance liquid chromatography. By contrast in genetically comparable dwarf ( II ) plants only labelled GA29 and 2-epiGA29 were produced in significant amounts, although evidence was obtained for trace amounts of labelled GA1 and GA8 . The apical portions of dwarf plants contained 8–10 times less GA1 than those of tall plants but at least as much GA20 (measured using di-deuterated internal standards). In conjunction with previous data these results strongly indicate that in genotype ll internode length is reduced and leaf growth altered by a reduction in GA1 levels attributable to a partial block in the 3β-hydroxylation of GA20 to GA1 .
In contrast to dwarf plants, semidwarf plants (genotype lblb ) contained more GA1 in the apical portion than wild-type counterparts. This is consistent with the suggestion that lb alters some aspect of GA sensitivity. 相似文献
In contrast to dwarf plants, semidwarf plants (genotype lblb ) contained more GA