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1.
Preincubation of dwarf, Rht3-containing deembryonated seed for 4 hours in 342 nanomolar indoleacetic acid (IAA) induced maximum sensitivity to GA 3. In addition, the 4-hour IAA pretreatment caused a 2-fold increase in total phospholipids which coincided identically on a temporal basis with the induced GA 3 sensitivity. Changes in absolute levels of individual phospholipids and their acyl groups were recorded and compared with the changes observed in several Rht-containing aleurone tissues which were induced to develop GA 3 sensitivity by exposure to low temperature (5°C). Several distinct similarities between all tissues were recorded as they develop GA 3 sensitivity. One parameter, the percentage phospholipid composition, was quite similar in all tissues after they had become maximally sensitive to GA 3, suggesting that there is at least one membrane phospholipid composition which is particularly responsive to GA 3. The results indicate that (a) the basis of the GA 3 insensitivity of the Rht mutation resides in an aberrant phospholipid/fatty acid composition and/or metabolism; (b) exposure to low temperature (5°C) for 20 hours or longer, or 342 nanomolar IAA for 4 hours or longer reverses or corrects the genetic lesion, enabling the tissue to adopt a GA 3 responsive membrane composition. Finally, an hypothesis is discussed which indicates that IAA may play a controlling role in the mobilization of endospermal reserves, at least in Rht3-containing wheat aleurone. 相似文献
2.
Exposure of isolated aleurone tissue from the wheat ( Triticum aestivum) variety Kite which contains the Rht2 allele, to low temperature (5°C) for 20 h prior to addition of exogenous GA 3, resulted in significant changes in the content of lipids, especially phospholipids. Significant low temperature-induced changes in both the head group and acyl contents of two phospholipids, phosphatidylcholine and phosphatidylethanolamine, were detected. More importantly, these changes displayed a very close temporal relationship with the low temperature-induced increase in GA 3 sensitivity. Further, this relationship was paralleled by a highly significant correlation between the changes in the phospholipids and the changes in α-amylase production. These results underline the possibility that the GA 3 receptor sites are membrane-based lipids. 相似文献
3.
Gibberellic acid (GA 3) sensitivity (measured as α-amylase production) of the isolated aleurone tissue/deembryonated seed of two wheat ( Triticum aestivum L. var Kite and var Aroona) varieties each containing either one of the dwarfing genes, Rht1 and Rht2, was increased significantly as a result of low temperature treatment. The magnitude of the low temperature-induced increase occurred without any change in the lag time of α-amylase production. This low temperature induction of GA 3 sensitivity was found to be operative in aleurone tissue of only those varieties having at least one of the three Rht alleles. It is likely, therefore, that the low temperature treatment effect which `cures' or circumvents the genetic lesions manifest in the Rht1 and Rht2 genotypes is the same as that effective in the Rht3-containing genotype and probably involves an increase in hormone (GA 3) receptor sites. Furthermore, this increase appears to be a quantitative temporal one. 相似文献
4.
Earlier, we reported that mutation in the Male Sterile33 ( MS33) locus in Arabidopsis thaliana causes inhibition of stamen filament growth and a defect in the maturation of pollen grains [Fei and Sawhney (1999) Physiol Plant 105:165–170; Fei and Sawhney (2001) Can J Bot 79:118–129]. Here we report that the ms33 mutant has other pleiotropic effects, including aberrant growth of all floral organs and a delay in seed germination and in flowering time. These defects could be partially or completely restored by low temperature or by exogenous gibberellin A 4 (GA 4), which in all cases was more effective than GA 3 Analysis of endogenous GAs showed that in wild type (WT) mature flowers GA 4 was the major GA, and that relative to WT the ms33
flowers had low levels of the growth active GAs, GA 1 and GA 4, and very reduced levels of GA 9, GA 24 and GA 15, precursors of GA 4. This suggests that mutation in the MS33 gene may suppress the GA biosynthetic pathway that leads to GA 4
via GA 9 and the early 13-H C 20
GAs. WT flowers also possessed a much higher level of indole-3-acetic acid (IAA), and a lower level of abscisic acid (ABA), relative to ms33 flowers. Low temperature induced partial restoration of male fertility in the ms33
flowers and this was associated with partial increase in GA 4. In contrast, in WT flowers GA 1 and GA 4 were very much reduced by low temperature. Low temperature also had little effect on IAA or ABA levels of ms33 flowers, but did reduce (>2-fold) IAA levels in WT flowers. The double mutants, ms33 aba1-1 (an ABA-deficient mutant), and ms33 spy-3 (a GA signal transduction mutant) had flower phenotypes similar to ms33. Together, the data suggest that the developmental defects in the
ms33 mutant are unrelated to ABA levels, but may be causally associated with reduced levels of IAA, GA 1 and GA 4, compared to WT flowers.Abbreviations ABA
Abscisic acid
- GA
Gibberellin
- GC-MS-SIM
Gas chromatography-mass spectrometry-selected ion monitoring
- IAA
Indole-3-acetic acid
- ms33
Male sterile33
mutant
- PP333
Paclobutrazol
- WT
Wild type 相似文献
5.
The hypothesis that auxin (IAA) and gibberellic acid (GA 3) control the formation of lignin is confirmed for the primary phloem fibers and for the secondary xylem in the stem of Coleus blumel Benth. Indoleacetic acid alone, or a combination of high IAA/low GA 3 (w/w), induced short phloem fibers with thick secondary walls, that contained lignin rich in syringyl units (high ratio of syringyl/guaiacyl). On the other hand, a combination of high GA 3/low IAA (w/w), which promoted the differentiation of long phloem fibers with thin walls, decreased the relative content of the syringyl units (low syringyl/guaiacyl ratio). In the secondary xylem, these hormonal treatments yielded only slight changes in the noncondensed monomeric guaiacyl units, confirming the relative stability of the guaiacyl lignification pattern in this tissue. In the xylem, indoleacetic acid alone, or a combination of high IAA/low GA 3 induced lignin poor in syringyl units (low syringyl/guaiacyl ratio). A combination of high GA 3/low IAA promoted a relatively slight increase in syringyl yield, indicating greater responsiveness of the syringyl lignification pattern to growth regulators. The possible functional and technological significance of our results is discussed. 相似文献
6.
Near-isogenic wheat ( Triticum aestivum L.) lines differing in height-reducing ( Rht) alleles were used to investigate the effects of temperature on endogenous gibberellin (GA) levels and seedling growth response to applied GA 3. Sheath and lamina lengths of the first leaf were measured in GA treated and control seedlings, grown at 11, 18, and 25°C, of six Rht genotypes in each of two varietal backgrounds, cv Maris Huntsman and cv April Bearded. Endogenous GA 1 levels in the leaf extension zone of untreated seedlings were determined by gas chromatography-mass spectrometry with a deuterated internal standard in the six Maris Huntsman Rht lines grown at 10 and 25°C. Higher temperature increased leaf length considerably in the tall genotype, less so in the Rht1 and Rht2 genotypes, and had no consistent effect on the Rht1+2, Rht3 and Rht2+3 genotypes. In all genotypes, endogenous GA 1 was higher at 25°C than at 10°C. At 10°C the endogenous GA 1 was at a similar level in all the genotypes (except Rht2+3). At 25°C it increased 1.6-fold in the tall genotype, 3-fold in Rht1 and Rht2, 6-fold in Rht3, and 9-fold in Rht1+2. Likewise, the genotypic differences in leaf length were very conspicuous at 25°C, but were only slight and often unsignificant at 11°C. The response of leaf length to applied GA 3 in the Rht1, Rht2, and Rht1+2 genotypes increased significantly with lowering of temperature. These results suggest the possibility that the temperature effect on leaf elongation is mediated through its effect on the level of endogenous GA 1 and that leaf elongation response to endogenous or applied GAs is restricted by the upper limits set by the different Rht alleles. 相似文献
7.
The hypothesis that auxin and gibberellic acid (GA 3) control the differentiation of primary phloem fibers is confirmed for the stem of Coleus blumei Benth. Indoleacetic acid (IAA) alone sufficed to cause the differentiation of a few primary phloem fibers. In long term experiments auxin induced a considerable number of fibers in mature internodes. GA 3 by itself did not exert any effect on fiber differentiation. Combinatiosn of IAA with GA 3 completely replaced the role of the leaves in primary phloem fiber differentiation qualitatively and quantitatively. Although the combined effect of the two growth hormones diminished considerably with increasing distance from the source of induction, auxin with GA 3 or IAA alone induced fibers in a few internodes below the application site. When various combinations of both hormones were applied, high concentrations of IAA stimulated rapid differentiation of fibers with thick secondary walls, while high levels of GA 3 resulted in long fibers with thin walls. The size of the primary phloem fibers correlated with the dimensions of the differentiating internode, thereby providing evidence that both growth regulators figure in the control of stem extension. High IAA/low GA 3 concentrations have an inhibitory effect on internode elongation, whereas low IAA/high GA 3 concentrations promote maximal stem elongation. 相似文献
8.
Enhanced amylase activity was observed during a 7-day-growth period in the cotyledons of PEG imposed water stressed chickpea seedlings grown in the presence of GA 3 and kinetin, when compared with stressed seedlings. During the first 5 days of seedling growth, the seedlings growing under water deficit conditions as well as those growing in the presence of PGRs had a higher amylase activity in shoots than that of control seedlings. Neither GA 3 nor kinetin increased the amylase activity of roots whereas IAA reduced root amylase activity. Activity of acid and alkaline invertases was maximum in shoots and at a minimum in cotyledons. Compared with alkaline invertase, acid invertase activity was higher in all the tissues. The reduced acid and alkaline invertase activities in shoots of stressed seedlings were enhanced by GA 3 and kinetin. Roots of stressed seedlings had higher alkaline invertase activity and GA 3 and IAA helped in bringing the level near to those in the controls. GA 3 and kinetin increased the sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities in cotyledons of stressed seedlings, whereas they brought the elevated level of SPS of stressed roots to near normal level. The higher level of reducing sugars in the shoots of GA 3 and kinetin treated stressed seedlings could be due to the high acid invertase activity observed in the shoots, and the high level of bound fructose in the cotyledons of stressed seedlings could be due to the high activity of SPS in this tissue. 相似文献
9.
Two-week-old dwarf peas ( Pisum sativum cv Little Marvel) were sprayed with gibberellic acid (GA 3), and after 3 or 4 days the upper stem and young leaf samples were analyzed for indole-3-acetic acid (IAA) and indole-3-acetyl aspartic acid by an isotope dilution high performance liquid chromatography method. GA 3 increased IAA levels as much as 8-fold and decreased indole-3-acetyl aspartic acid levels. 相似文献
10.
Actinomycin D inhibited the elongation of epicotyl segmentsfrom azuki bean seedlings that was induced by simultaneous treatmentwith IAA and GA 3. The drug also inhibited the elongation ofthe segments that was caused by IAA alone when it was appliedtogether with IAA. When the segments were pretreated with GA 3and then incubated with IAA, GA 3 promoted the elongation causedby IAA and brought about a predominance of transverse corticalmicrotubules (MTs) in the epidermal cells of the segments. Thechange in the arrangement of MTs caused by pretreatment withGA 3 was evident 1 h after the start of subsequent incubationwith IAA when the effect of pretreatment with GA 3 on the elongationhad not yet become apparent. Pretreatment with GA 3 did not causeany change in the arrangement of MTs when GA 3-pretreated segmentswere not incubated subsequently with IAA. Although actinomycinD applied before treatment with IAA did not inhibit the IAA-inducedelongation, the drug diminished the promotion of the elongationcaused by pretreatment with GA 3 and prevented GA 3 from bringingabout a predominance of transverse MTs when the drug was appliedduring the pretreatment with GA 3. GA 3-induced synthesis of mRNA seems to be involved in the promotionby GA 3 of IAA-induced elongation and in the GA 3-induced rearrangementof cortical MTs. (Received June 15, 1993; Accepted August 16, 1993) 相似文献
11.
Ramie ( Boehmeria nivea L. Gaud) fibers extracted from the stem bast is one of the most important natural fibers. Ramie growth is severely hindered by drought stress but is promoted by gibberellins (GAs). In order to investigate ramie morphological and physiological responses to drought stress and GA 3 treatment, four groups of potted ramie (severe drought stress (DS), severe drought stress and spraying with GA 3 (DS + GA 3), normal watering and spraying with GA 3 (control + GA 3), and normal watering as a control) were tested. The result showed that, comparing with the ramie growing under well watering condition, a decrease in chlorophyll a (Chl a) and carotenoid and an increase in proline and soluble sugar contents were commonly observed in drought-stressed and GA 3-treated ramie. Different responses of the stem morphological traits, fiber yield, and seven physiological characteristics (relative water content, the activities of POD, SOD, and CAT enzymes, the contents of Chl b, endogenous GAs and MDA) were observed between drought-stressed and GA 3-treated plants. When the ramie suffering drought stress was sprayed with GA 3 (in (DS + GA 3) group), the responses of some physiological traits (POD, SOD, CAT, MDA, and endogenous GAs) and morphological traits (stem shape and fiber yield) to drought stress disappeared completely or partially, and the plant presented similar characteristics of well-watered ramie in these traits. These results suggested that the application of exogenous GA 3 can improve the drought tolerance of ramie. 相似文献
12.
The purpose of this study was to analyze the nature of the interaction between gibberellic acid (GA 3) and abscisic acid (ABA) in the regulation of growth in excised Avena (oat) stem segments. Growth, compared to sucrose controls, was inhibited by ABA in the range of 10 ?4 to 10 ?6M. GA 3-promoted growth was also inhibited by ABA in the same concentration range. A Lineweaver-Burk analysis of the interaction between GA 3 and ABA indicated that ABA acts in a non-competitive fashion with GA 3. This same result was obtained previously with GA 3-indoleacetic acid (IAA) and GA 3-kinetin interactions with Avena stem sections. Our results indicate that ABA can inhibit GA 3-promoted growth within physiological concentrations, and that it is probably acting at a different physiological site from that for GA 3. 相似文献
13.
Gibberellic acid (GA 3) induced a marked elongation of 2.5-centimeter shoot tips of Cuscuta chinensis Lamk. cultured in vitro. In terms of the absolute amount of elongation, this growth may be the largest reported for an isolated plant system. The response to hormone was dependent on an exogenous carbohydrate supply. The hormone-stimulated growth was due to both cell division and cell elongation. The growth response progressively decreased if GA 3 was given at increasingly later times after culturing, but the decreased growth response could be restored by the application of indole-3-acetic acid (IAA) to the apex. Explants deprived of GA 3 gradually lost their ability to transport IAA basipetally, but this ability was also restored by auxin application. The observations are explained on the basis that: ( a) the growth of Cuscuta shoot tip in vitro requires, at least, both an auxin and a gibberellin; and ( b) in the absence of gibberellin the cultured shoot tip explants lose the ability to produce and/or transport auxin. 相似文献
14.
Indole-3-acetic acid (IAA) and gibberellic acid (GA3) are essential for the growth and development of plants. In the present study, the ameliorative potential of these phytohormones on growth, protein content, and antioxidant enzymes was investigated in in vitro-grown Solanum tuberosum L. cultivars ‘Cardinal’ and ‘Desiree’ under salt stress. A 4 × 3 factorial combination of 0, 40, 60, or 80 mM NaCl with 0, 7, or 14 μM IAA, or 0, 14, or 21 μM GA3, were added to Murashige and Skoog (MS) basal medium, followed by inoculation of nodal explants or callus cultures. The data for root and shoot number and length, number of nodes and leaves, fresh weight of plants, increase or decrease in fresh weight of callus cultures, total soluble protein, and superoxide dismutase (SOD) and peroxidase (POD) activities were recorded after 30 d. The growth of both callus cultures and nodal explants subjected to NaCl stress was substantially reduced compared with the control. Both IAA and GA3 successfully alleviated the harmful effects of salt stress on all of the growth parameters studied. Salt stress resulted in decreased protein content, which increased when the media also contained phytohormones. The activities of SOD and POD were increased with either IAA or GA3 under NaCl stress. Therefore, the exogenous application of both IAA and GA3 not only played a positive role in terms of in vitro potato growth but also significantly affected the biochemical parameters tested. 相似文献
15.
Indole-3-acetic acid (IAA) strongly enhanced rooting of etiolated pea epicotyl cuttings while gibberellic acid (GA 3) enhanced rooting only slightly. The promoting effects of the hormones appeared not until 14 d after the onset of treatment. When GA 3 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
- GA 3
Gibberellic acid 相似文献
16.
The temporal and spatial changes in reactive oxygen species (ROS) during dark treatment of Pelargonium cuttings and the effect of gibberellic acid (GA 3) on ROS levels were studied. ROS-related fluorescence was detected in mitochondria and cytoplasm of epidermal cells and in
chloroplasts. By monitoring dichlorofluorescein (DCF) fluorescence, an initial decrease in ROS was observed under darkness
in the epidermal cell cytoplasm and the chloroplasts, which was followed by an increase on the third day. Following 3 days
under darkness, the size and the structure of the chloroplasts also changed, and they became more sensitive to illumination
as judged by a higher accumulation of ROS. Pretreatment of leaves with GA 3 did not prevent the structural changes in the chloroplasts, but it inhibited the increase in ROS levels in all cell compartments,
including the chloroplasts. It is suggested that the inhibition of ROS increase by GA 3 prevented complete disintegration of chloroplasts during dark-induced senescence and thereby enabled the maintenance of chlorophyll
levels in the tissue. 相似文献
17.
Cuttings of potato shoots treated with the plant growth retardant 2-chloroethyltrimethyl ammonium chloride (CCC) form tubers earlier and have less biologically-active gibberellin (GA)-like substances in the roots than control cuttings. The major GA-like substance in roots of potato cuttings was identified as GA 3 by gas-chromatography-mass spectrometry (GC-MS). The content of GA 3 in roots of control cuttings, estimated by GC-MS-selected ion monitoring (SIM) using [17, 17- 2H]GA 3 as a quantitative internal standard, was 38.8 ng per g fresh weight (fw), and in roots of CCC-treated cuttings, in which tuberization was promoted, was 0.6 ng per g fw. Gibberellin A 1, GA 8 and GA 20 were also indicated as minor components of roots from both control and CCC-treated cuttings. The comparatively high GA 3 content in roots of control cuttings might be the root factor responsible for delaying tuberization in potato.Abbreviations CCC
2-chloroethyltrimethyl ammonium chloride
- dw
dry weight
- EtOAc
ethyl acetate
- GA
gibberellin
- GC-MS-SIM
gas chromatography-mass spectrometry-selected ion monitoring
- HPLC
high performance liquid chromatography
- IAA
indole-3-acetic acid
- KRI
Kovats' retention index
- MeOH
methanol
- MeTMSi
methyl ester trimethylsilyl ether
- NAA
naphthalene acetic acid
- SD
short day(s)
- 2,4-D
2,4-dichlorophenoxy acetic acid 相似文献
18.
GA 24-7,19-dimethyl ester was converted to dihydro GA 24-Me-17-chloroformate and dihydro GA 24-Me- 17-cyanoacetate and coupled to bovine serum albumin. Antisera raised in rabbits against these immunogens were highly reactive with GA 24-7,19-dimethyl ester and were employed in a sensitive HPLC-radioimmunoassay (detection limit of RIA: 0.1–0.2 pmol) using GA 24-7-methyl ester-19-tritiated methyl ester as tracer. Some sera were also reactive with GA 19-Me,GA 53-Me and GA 12-Me. Levels of GA 19 in immature seeds of Pharbitis nil obtained by RIA were compared to those obtained with an established GC/MS procedure and were found identical within the limits of experimental error. The synthetic procedures reported here should be applicable to a range of other gibberellins. The results exemplify the applicability of immunological assays to the analysis of C 20-gibberellins. 相似文献
19.
Dog rose ( Rosa canina L.) plants in the bloom stages of flowering were sprayed by indole-3-acetic acid (IAA) in concentrations of 0.06 and 0.60 mM and gibberellic acid (GA 3) in concentrations of 0.60 and 1.50 mM. Ascorbic acid, total sugar, reducing sugar and carotenoid contents gradually increased, while the protein content remained unchanged and the content of phenolic substances decreased during hypanthium development. Ascorbic acid, total sugar, reducing sugar and carotenoid contents increased in hypanthium sprayed by GA 3 and IAA. However, IAA and GA 3 applications (except low concentrations) decreased contents of phenolic substances. IAA and GA applications might be a good way to produce the high quality hypanthium in R. canina. 相似文献
20.
Satsuma [ Citrus unshiu (Mak) Marc.] and Clementine [ Citrus reticulata (Hort.) Ex. Tanaka, cv. Oroval] are two related species of seedless mandarins which differ in their tendency to set parthenocarpic fruits. Satsuma fruits naturally set parthenocarpically whereas Clementine mandarins show very low ability to set fruit in the absence of cross-pollination. The endogenous levels of gibberellins (GAs) and free and conjugated indole-acetic acid (IAA) and abscisic acid (ABA) throughout early stages of fruit development were investigated in seedless cultivars of both species. Analyses performed by full-scan combined gas chromatography-mass spectrometry (GC-MS) of extracts from ovaries at anthesis demonstrated the presence of GA 19, GA 20, GA 29, GA 1, GA 8, GA 3 and iso-GA 3 in Satsuma mandarin, whereas only GA 29, GA 3 and trace levels of GA 8 were detected in Clementine. At this developmental stage GA-like substances, as estimated by bioassay, reached their highest levels in Satsuma, while Clementine mandarins contained relatively lower levels. In both species the highest levels of free IAA were found at petal-fall stage at which time free ABA levels also peaked. Developing fruits of Clementine had higher amounts of both free IAA and ABA. In Satsuma, levels of conjugated IAA remained low throughout reproductive development whereas in Clementine they increased as the free form declined. In contrast, conjugated ABA was at low levels in Clementine but reached higher concentrations in Satsuma. These results suggest that in these mandarins the potential for setting parthenocarpic fruits is mainly influenced by the hormonal status of the fruit during the later stages of cell division and early stages of cell enlargement. Thus, the condition of low ability to set parthenocarpic fruits appears to be associated with lower levels of active GAs, lower capability to catabolize ABA to conjugated ABA and higher ability to conjugate IAA during this period. 相似文献
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