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1.
The role of endogenous GA3 and its application to seed development in two cotton genotypes Hybrid-6 (H-6) (big seeds) and Gujarat cotton 13 (G. Cot) (small seeds) was studied. Kernel and seed coat were subjected to growth analysis in terms of dry weight, water amount, and rates of dry matter accumulation and water uptake. H-6 kernel had manifold higher dry weight and water amount than G. Cot. Seed coat of both genotypes had similar dry weight at maturity, but the maximum rates of dry matter accumulation and water uptake were distinctly higher in H-6. According to growth analysis, development of seed kernel and coat was subdivided into four phases, i.e., cell division, cell elongation, dry matter accumulation and maturation. Endogenous GA3 level was estimated in kernel and seed coat by indirect ELISA using antibodies raised against GA3. GA3 amount per seed components was higher in the seed kernel of H-6 than of G. Cot, except 33 and 36 days after anthesis in kernel. H-6 seed coat had the higher amount of GA3 during cell division phase than that of G. Cot. Close correlation between in vivo GA3 level and water amount was recorded in both seed components. With GA3 or GA3 + NAA treatments in ovule culture, higher promotion in dry weight, water amount and seed size was noted in G. Cot than in H-6 suggesting that G. Cot is more deficient in endogenous GA3. The greatest stimulation of parameters studied was obtained in ovule culture with GA3 + NAA. When GA3 or GA3 + NAA was applied, initial significant difference in water amount and seed size was nullified. Data presented in this study indicated that GA3 regulates cell expansion through the water uptake by cotton seed.  相似文献   

2.
This study concerns the effects of four different classes of plant growth regulators on root morphology, patterns of growth and condensed tannin accumulation in transgenic root cultures of Lotus corniculatus L. (Bird's-foot trefoil). Growth of transformed roots in 2,4-dichlorophenoxyacetic acid (2,4-D) resulted in decreased tannin levels relative to controls at concentrations of 10-6 M and above, while gibberellic acid (GA3) inhibited tannin accumulation at concentrations of 10-7 M and above. Benzyladenine (BA) had little effect at low concentrations (10-7 M and below) but resulted in an increase in tannin levels at 10-6 M. Abscisic acid had little effect on levels of condensed tannins at any of the concentrations used. Experiments involving growth regulator addition and medium transfer demonstrated that 2,4-D inhibition of tannin accumulation could be reversed by GA3 and BA, while GA3 downregulation could only be reversed by the addition of 2,4-D. Although 2,4-D inhibited tannin accumulation, addition of 2,4-D to root cultures grown for 14 or 28 days in the absence of plant growth regulators stimulated both growth and tannin biosynthesis. Characteristic alterations in root morphologies accompanied growth regulator-mediated modulation of tannin biosynthesis. Growth in 2,4-D resulted in partially de-differentiated root cultures while growth in GA3 produced roots with an elongated phenotype. Restoration of tannin biosynthesis in 2,4-D-treated roots was accompanied by root re-differentiation and the production of new lateral roots.Abbreviations ABA abscisic acid - BA benzyladenine - 2,4-d 2,4-dichlorophenoxyacetic acid - GA3 gibberellic acid 3 - FW fresh weight  相似文献   

3.
We isolated 864 bacteria from 553 soil samples and bioassayed them on cucumber and crown daisy for plant growth promotion. A new bacterial strain, Burkholderia sp. KCTC 11096BP gave maximum growth promotion and was selected for further investigations. The culture filtrate of this bacterium was thus analyzed for the presence of gibberellins and we found physiologically active gibberellins were found (GA1, 0.23 ng/100 ml; GA3, 5.11 ng/100 ml and GA4, 2.65 ng/100 ml) along with physiologically inactive GA9, GA12, GA15, GA20, and GA24. The bacterial isolate also solubilised tricalcium phosphate and lowered the pH of the medium during the process. The isolate was identified as a new strain of Burkholderia through phylogenetic analysis of 16S rDNA sequence. Gibberellin production capacity of genus Burkholderia is reported for the first time in current study. These authors contributed equally to the work  相似文献   

4.
Embryos isolated from dormant apple seeds were treated with jasmonic acid (JA), gibberellin A3 (GA3), abscisic acid (ABA) and hydrogen cyanide in darkness and in light. The chemicals were present in the culture medium continuously and simultaneously or applied for 2 days and in different sequences. All treatments stimulated embryo germination except ABA, which was strongly inhibitory. Additive effects of JA with light and with GA3 on embryo germination were observed, whereas ABA interacted synergically with JA, HCN and light. ABA and GA3 were most effective when applied early during embryo incubation, but the late JA treatment was more stimulatory. It is concluded that JA does not act on the regulatory pathway that is initiated by light and which leads to embryo germination through gibberellin accumulation and alkaline lipase activation. ABA and HCN appear to be involved in the control of this pathway. JA and ABA may be involved in the control of alkaline lipase activity, independently of this regulatory chain.Abbreviations ABA abscisic acid - GA3 gibberellin A3 - JA jasmonic acid  相似文献   

5.
The culture conditions for gibberellic acid (GA3) production by the fungus Penicillium variable (P. variable) was optimized using a statistical tool, response surface methodology (RSM). Interactions of culture conditions and optimization of the system were studied using Box–Behnken design (BBD) with three levels of three variables in a batch flask reactor. Experimentation showed that the model developed based on RSM and BBD had predicted GA3 production with R 2  = 0.987. The predicted GA3 production was optimum (31.57 mg GA3/kg substrate) when the culture conditions were at 7 days of incubation period, 21% v/w of inoculum size, and 2% v/w of olive oil concentration as a natural precursor. The results indicated that RSM and BBD methods were effective for optimizing the culture conditions of GA3 production by P. variable mycelia.  相似文献   

6.
Endophytic fungi are plant symbionts that produce a variety of beneficial metabolites for plant growth and protection against herbivory and pathogens. Fourteen fungal samples were isolated from the roots of soybean cultivar Daemangkong and screened on waito-c rice for their plant growth-promoting capacity. Twelve of the fungal isolates promoted plant growth, while two inhibited it. The fungal isolate DK-1-1 induced maximum plant growth in both waito-c rice and soybean. The plant growth promotion capacity of DK-1-1 was higher than the wild type Gibberella fujikuroi. Gibberellin (GA) analysis of culture filtrate of DK-1-1 showed the presence of higher amounts of bioactive GA3, GA4, and GA7 (6.62, 2.1 and 1.26 ng/mL, respectively) along with physiologically inactive GA5, GA15, GA19, and GA24. Phylogenetic analysis of 18S rDNA sequence identified the fungal isolate as a new strain of Cladosporium sphaerospermum. Gibberellin production and plant growth-promoting ability of genus Cladosporium are reported for the first time in the present study. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

7.
Exogenous plant growth regulators are known to increase the efficiency of interspecific and intergeneric crosses. In vitro floret culture provides a defined system for assessing the importance of various plant growth regulators on the determinants of haploid production efficiency (seed set, embryos per seeds, and plants per embryos) in Hordeum vulgare × Hordeum bulbosum crosses. The individual and combined effects of three plant growth regulators (2,4-D, GA3 and kinetin) on in vitro seed growth, embryo development and haploid production efficiency were tested in floret culture of the cross H. vulgare, cultivar Klages × H. bulbosum. All treatments, except kinetin alone, produced larger seeds and more embryos/100 seeds than the control (no plant growth regulator). 2,4-D alone was superior to GA3 alone in haploid production efficiency (70.6 vs. 51.5) as measured by the number of plants regenerated/100 florets pollinated. Although kinetin +2,4-D+GA3 produced the largest seeds and embryos, no advantage over 2,4-D alone was observed in haploid production efficiency. 2,4-D alone or kinetin +2,4-D are recommended for the purpose of barley haploid production in floret culture using the bulbosum method.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - GA3 gibberellic acid  相似文献   

8.
GA3 was identified as a major GA in Neurospora crassa by gas chromatography/selected ion monitoring (GC/SIM) and its content was measured at various stages (0~96 hr after inoculation) of conidial germination and mycelial growth. The GA3 content in the fungus was 190ng/g dry weight at the initial stage and then decreased rapidly; that per liter culture decreased soon after the inoculation, and then increased to 17.6 ng 96 hr after inoculation. The GA3 concentration in the culture medium was around 10?11 m throughout the 96-hr incubation. The physiological role of endogenous GA in Neurospora crassa is also discussed.  相似文献   

9.
为探讨培养条件对勺叶茅膏菜(Drosera spatulata)试管苗矶松素积累的影响,采用高效液相色谱(HPLC)法测定矶松素含量,对不同器官和不同培养条件下的勺叶茅膏菜试管苗矶松素含量变化进行研究。结果表明,勺叶茅膏菜试管苗根的矶松素含量显著高于叶片;光质和有机物含量对勺叶茅膏菜试管苗矶松素含量的影响不显著,但对试管苗的生长具有显著影响,最佳培养光质为白光,其次为红光和蓝光,最后为绿光;适当降低培养基中有机物含量可促进勺叶茅膏菜试管苗的生长发育;植物生长调节剂对矶松素积累的影响效应依次为6-BANAAKTGA3,而对试管苗生长的影响效应依次为6-BAGA3NAAKT。因此,勺叶茅膏菜试管苗的最佳培养条件为:以1/2MS为基本培养基,添加0~0.2 mg L–1 6-BA、0.2 mg L–1 NAA、0.5 mg L–1KT和0.1 mg L–1 GA3,于白光下培养。  相似文献   

10.
Xuesha Ke  Wei Li 《Hydrobiologia》2006,556(1):243-249
Seedling survival and growth of two common Vallisneria species in China, Vallisneria natans and Vallisneria spinulosa were quantified experimentally for current velocities from 0 to 40 mm/s. At the same time, changes in the concentrations of three hormones (IAA, ZR, and GA3) in the leaves were compared to identify how current velocity influenced the two Vallisneria seedlings growth discrepantly. All plants survived in all treatments and showed positive growth. The most rapid growth for both species was found at the velocity of 10 mm/s. Although V. spinulosa showed faster growth than V. natans at the beginning of the experiment, there was no significant difference on final biomass. Higher IAA and ZR contents were measured in seedlings of both species grown under low current velocity. The time reaching the maximum for IAA and ZR was just around the time of a maximum seedling growth rate. IAA and ZR contents were positively correlated with growth rate. However, GA3 was negatively associated with growth rate and more GA3 in V. natans seedlings was induced by high current velocity.  相似文献   

11.
Endopeptidase activity in cotyledons of 5-day seedlings of Pisum sativum increased rapidly during germination. However, the increase of the activity in detached cotyledons was depressed. We examined whether a growth regulator can be substituted for the embryonic axis on the development of endopeptidase activity. As monitored by an assay with azoalbumin, the development of endopeptidase activity from crude extracts of detached cotyledons appeared to be slightly accelerated by incubation with 10–5 M GA3. However, the pattern after gelatin-polyacrylamide gel suggested that the activity induced in detached cotyledons during a 5-d incubation at 10–7 M GA3 was the same as that in attached ones during germination for 5 days and an even greater increase in activity was obtained with 10–5 M GA3. These results suggest that GA3 from the embryonic axis induces endopeptidase activity in attached cotyledons at the first stage of germination.Abbreviations ABA abscisic acid - IAA indole-3-acetic acid - GA gibberellic acid  相似文献   

12.
This study analysed the dynamics of cell production and extension, and how these were affected by applied gibberellic acid (GA3), during internode development in dwarf peas (Pisum sativum L. cv. Meteor). Image analysis was used to obtain cell number and length data for entire cell columns along the epidermis, the two outermost cortical layers, and the pith, from internode 7, over a time period covering the whole of the internode's growth phase. For a few days following the inception of an internode at the shoot apex, little further growth occurred, and there was no significant effect of GA3 on cell division or cell extension. The subsequent growth of the internode was stimulated more than fourfold by GA3 as a result of the production of more than twice the number of cells, which were twice as long. At least 96.5% of the cells of the mature internode were actually formed within the internode itself during this period of growth, demonstrating that the internode cells themselves represent the morphogenetic site of response to GA3. Mitoses and cell extension occurred along the full length of the internode throughout its development. The daily changes in cell numbers were modelled by the Richards function, and manipulations of the fitted functions to reveal time trends of absolute and specific cell production rates were performed for each stem tissue. The increase in cell numbers in the +GA3 plants was brought about by an increase in the rate of cell production, over a shorter time interval; specific cell production rates declined continuously from initial rapid rates in the +GA3 epidermis and pith, but declined more slowly in the cortex. The control (−GA3) epidermis and cortex cells exhibited a constant specific cell production rate (i.e. purely exponential) for several days. Cell extension rates were calculated so as to compensate for the size-reduction effects of concurrent cell division. These calculations confirmed that `real' cell extension rates were higher in the +GA3 internodes. Models of the cellular controls of internode growth, based on the estimated dynamics of cell division and extension, are discussed. Received: 1 July 1997 / Accepted: 30 July 1997  相似文献   

13.
We investigated the influence of gibberellic acid (GA3; 0, 1, 10, and 100 μM) on Nostoc linckia culture at 7, 14, and 21 days. The fresh and dry weight of N. linckia was increased considerably by the 10 and 100 μM GA3 treatments. A reduction in heterocyst frequency was observed in cultures treated with 1 and 10 μM GA3. Adding GA3 to N. linckia culture had a little effect on cell size. The amount of chlorophyll a and carotenoids decreased at all concentrations of GA3. The amount of phycocyanin increased up to twofold in 7-day-old culture treated with 1 μM GA3, and similar changes were observed for allophycocyanin and phycoerythrin content after 7 days. The effect of GA3 on reducing sugar content was different and was dependent on the growth period. A reduction in soluble sugar content was detected after GA3 application in 7- and 14-day-old cyanobacteria. Cultures treated with GA3 had a higher protein content after 14 days and a lower protein content after 7 and 21 days, and reduced nitrogenase activity after 7, 14, and 21 days. Our data show that GA3 application can be a suitable and inexpensive way to increase N. linckia biomass and phycobiliprotein production.  相似文献   

14.
Carol Moll  Russell L. Jones 《Planta》1981,152(5):442-449
The short-term kinetics of growth of the excised lettuce (Lactuca sativa L.) hypocotyl were characterized with respect to the effects of gibberellic acid (GA3), indole-3-acetic acid (IAA), KCl and pH. A Hall-device-based, miniaturized, linear displacement transducer was developed to measure the growth of 2-mm hypocotyl sections with 1-m resolution. Following treatment with GA3, a lag time of less than 10 min was typically followed by an increase in growth rate with two acceleration phases, reaching a final elevated rate within about 1 h. The kinetics of the response to GA1, a mixture of GA4 and GA7, and GA9 were similar to the response to GA3. There was no response to IAA treatment either in the presence or absence of GA3. KCl alone had no effect on the growth rate, but caused an increase in rate when added after GA3, with a lag time of usually less than 1 h. Responses to pH changes had lag times of a few minutes in all cases. A shift from H2O to pH 6 buffer inhibited growth, while a shift from H2O to pH 4 buffer resulted in a transient increase to a rate comparable to that induced by GA3. A shift from pH 6 to pH 5 caused an increase in growth rate, followed by a gradual decline to an H2O control rate after more than an hour. The responses to GA3 at pH 4 and pH 5 were similar to that found for addition of GA3 to water controls.Abbreviations GA gibberellin - GA3 gibberellic acid - GA1, GA4+7, GA9 gibberellins A1, A4+7, A9 - IAA indole-3-acetic acid  相似文献   

15.
A significant depression of callus growth resulted from low concentrations of abscisic acid (ABA) added to the medium recommended by Linsmaier and Skoog. Low concentrations also decreased the chlorogenic acid and lignin content of the callus, and generally decreased amounts of scopolin and scopoletin in the tissue. Gibberellic acid (GA3) stimulated callus growth in a low concentration (0.1 mg/1) and inhibited growth at a high concentration (10.0 mg/1). Both levels of GA3 increased scopoletin accumulation in tobacco callus. A high concentration of GA3 increased the accumulation of scopolin and chlorogenic acids, whereas a low concentration decreased the amounts of these two phenolic compounds. In comparison with the control, lignin synthesis was stimulated by a low GA3 concentration, but a high GA3 concentration did not have a significant effect. Both low and high concentrations of GA3 overcame ABA inhibition of growth and lignin synthesis, and partially reversed ABA inhibition of scopoletin production. However, GA3 did not reverse the inhibitory effect of ABA on scopolin production. The low concentration of GA3 overcame the inhibition of chlorogenic acid production resulting from a 0.01 mg/1 concentration of ABA, but this was the only reversal of chlorogenic acid inhibition resulting from addition of GA3 to the medium.  相似文献   

16.
Richard Hooley 《Planta》1982,154(1):29-40
Viable, long-lived, gibberellic acid (GA3)-responsive protoplasts have, for the first time, been isolated from aleurone layers of mature wild oat (Avena fatua L.) grain. More than 90% of the cells of aleurone layers are recovered as protoplasts, and these respond to treatment with GA3 in essentially the same manner as the tissue from which they were derived. Protoplasts become vacuolate during incubation in vitro and, although not dependent upon GA3, vacuolation is markedly stimulated by the hormone. Amylase and ribonuclease (RNase) are produced and secreted only in the presence of GA3 and only after lag periods of 3 d and 4 d respectively. The amounts of amylase produced and secreted are proportional to GA3 concentrations as low as 1.61·10-13 M. With increasing concentrations of mannitol in the culture medium both vacuolation and the GA3-induced production and secretion of enzymes are inhibited progressively, the latter being precluded by 0.6 M to 0.7 M mannitol.Abbreviations GA3 gibberellic acid3 - RNase ribonuclease  相似文献   

17.
The germination of seeds of celery (Apium graveolens L.) becomes progressively thermoinhibited on incubation in the dark at high temperatures, the inhibitory temperature being dependent on the cultivar used. In two high-dormancy cultivars of celery, the production of germination inhibitors in seeds incubated in the dark at 26°C gradually increased over a 7-day period. Inhibitor production was measured by incubating seeds of the low-dormancy cultivar Florida 683 in homogenates of the thermoinhibited seeds of the high-dormancy cultivars and recording germination either in the light or with the gibberellins A4 and A7 (GA4/7) in the dark. Most Florida 683 seeds which failed to germinate in the homogenates after 15 days were induced to germinate by addition of N6-benzyladenine (BA). The presence of BA in addition to GA4/7 throughout incubation in the dark completely overcame the inhibitory effects of homogenates. This indicates that thermoinhibition of celery seeds is associated with the accumulation of a germination inhibitor which interacts with cytokinins. This does not appear to be abscisic acid (ABA) since ABA levels in thermoinhibited seeds were lower than in untreated seeds and did not increase with duration of high temperature treatment.Abbreviations ABA Abscisic acid - BA N6-benzyladenine - GA4/7 a mixture of the gibberellins A4 and A7 - HTP high-temperature pretreatment  相似文献   

18.
Although fruit set and development are induced by applications of gibberellins, final fruit weight of gibberellin-induced parthenocarpic fruit is often less than that of pollinated fruit. We examined changes in the activities of sucrose-metabolizing enzymes and sugar accumulation in developing fruits of cultivated blueberry (Vaccinium ashei Reade) and their correlation with fruit growth upon pollination or exogenous applications of gibberellic acid (GA3). The objective was to determine if differences in fruit growth could be attributed to differences in enzyme activities and subsequent sugar accumulation in fruits. The fruit development period of GA3-treated fruits was 15 days longer than that of pollinated fruits. At maturity, GA3-treated fruit accumulated an average of 180 mg dry weight while pollinated fruit accumulated 390 mg dry weight. Dry weight accumulation in nonpollinated fruits was negligible and these fruits abscised by 45 days after bloom (DAB). The total carbon (C) cost (dry weight C + respiratory C) for fruit development was 109 and 244 mg C fruit-1 for GA3-treated and pollinated fruits, respectively. Hexose concentration increased to 100 mg (g fresh weight)-1 at ripening in both GA3-treated and pollinated fruits. Nonpollinated fruits reached a maximum hexose concentration at 45 DAB. Sucrose phosphate synthase (EC 2.4.1.14) and sucrose synthase (EC 2.4.1.13) activities reached a maximum of ≤5.0 μmol (g fresh weight)-1 h-1 in both GA3-treated and pollinated fruits. Soluble acid invertase (EC 3.2.1.26) activity increased to about 60 μmol (g fresh weight)-1 h-1 in both GA3-treated and pollinated fruits at ripening, while in nonpollinated fruits, a maximum soluble acid invertase activity of 0.12 μmol (g fresh weight)-1 h-1 was measured at 24 DAB. Insoluble acid invertase activity declined during the early stages of fruit growth and remained relatively low throughout fruit development. Neutral invertase activity was low throughout development, increasing to 5 μmol (g fresh weight)-1 h-1 at ripening in GA3-treated and pollinated fruits. Our studies demonstrate that blueberry fruit development does not appear to be limited by sucrose metabolizing enzyme activity and/or the ability to accumulate sugars in either GA3-treated or pollinated fruits.  相似文献   

19.
The correlation between gibberellin (GA) metabolism and growth rate was investigated using two Sorghum bicolor inbred lines, Hegari and AT×623, and their heterotic F1 hybrid. Previous studies have demonstrated that this hybrid is taller and has substantially greater shoot dry weights and leaf areas than either parental inbred. [3H]GA20 was applied to the leaf whorl of seedlings and after 24 hours, plants were harvested and separated into roots, shoot cylinders containing the apical meristems, and leaf blades. Chromatographic analyses of metabolites indicated the conversions of [3H]GA20 to [3H]GA1,8 and 29. The conversion of [2H]GA20 to [2H]GA1 was demonstrated by gas chromatography-selected ion monitoring (GC-SIM). Putative glucosyl conjugates of all of the [3H]GAs were also produced and GA8 was identified by GC-SIM following enzymic cleavage of the putative [3H]GA8 glucosyl conjugate fraction. Comparing the genotypes, [3H]GA20 metabolism was more rapid in the shoot cylinders of the hybrid than in the shoot cylinders from inbreds. In the hybrid samples, there was a three-fold increase in the putative conjugate(s) of [3H]GA1 which was the principal metabolite, and increased production of [3H]GA8 and the putative conjugates of [3H]GA29 and [3H]GA8. Conversely, levels of the remaining precursor, [3H]GA20, and its putative conjugate(s) were reduced in the hybrid. The rate of GA20 metabolism was thus positively correlated with growth rate across these sorghum genotypes. This correlation supports a promotive role of GA in the regulation of shoot growth and in the expression of heterosis (hybrid vigor) in sorghum.  相似文献   

20.
Endophytic fungi are known to play a vital role in the growth and development of their host plants. We isolated eleven endophytic fungi from the roots of sand-dune plant Elymus mollis and their growth-promoting ability was studied on waito-c rice and Atriplex gemelinii. We found that eight fungal isolates promoted growth of both plants. Fungal isolate EM-7-1 induced maximum growth promotion in waito-c rice (9.25 cm) and Atriplex gemelinii (3.1 cm), which was higher than wild-type Gibberella fujikuroi. Gibberellin analysis of EM-7-1 culture filtrate showed the presence of bioactive gibberellins GA1 (0.32 ng/ml), GA3 (5.76 ng/ml), GA4 (0.82 ng/ml) and GA7: (0.1 ng/ml) along with physiologically inactive GA5 (0.59 ng/ml), GA9 (5.38 ng/ml), GA20 (0.25 ng/ml) and GA24 (2.03 ng/ml). The fungal isolate EM-7-1 was identified as new strain of Gliomastix murorum (G. murorum KACC43902) with 99% sequence homology. This study reports the plant growth-promoting ability of genus Gliomastix and the presence of GA5 in the culture filtrate of fungi for the first time. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

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