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Daminozide and prohexadione have similar modes of action as inhibitors of the late stages of gibberellin metabolism 总被引:1,自引:0,他引:1
Robert G. S. Brown Hiroshi Kawaide Young-Yell Yang Wilhelm Rademacher Yuji Kamiya 《Physiologia plantarum》1997,101(2):309-313
One of the effects of daminozide is to retard shoot growth in certain plant species, but its mode of action is unclear. Prohexadione, an acylcyclohexanedione, also causes retardation of shoot growth, but it is active in all plant systems tested so far. This inhibition has been shown to be a result of competition with the natural co-substrate, 2-oxoglutarate, at the active site of hydroxylases involved in the later stages of the gibberellin (GA) biosynthesis pathway. In order to determine the mode of action of daminozide in relation to prohexadione, the potencies of the two retardants as inhibitors of 3β-hydroxylation of GAs in cell-free systems from pumpkin ( Cucurbita maxima ) endosperm and French bean ( Phaseolus coccineus ) cotyledons were studied. Several compounds, related to or representing structural links between daminozide and prohexadione, were also included in this investigation. Daminozide was found to inhibit only the bean 3β-hydroxylase to a significant degree, whereas prohexadione inhibited both the bean and pumpkin enzymes.
Further information was obtained from the GC-MS analysis of GAs found in the newly formed parts of the shoots of peanut seedlings treated with the two compounds. Both growth retardants inhibited the formation of GA1 , whereas its immediate precursor, GA20 , accumulated. Furthermore, levels of GA8 (2β-hydroxy GA1 ) were also reduced, but by a smaller relative amount.
These results clearly indicate for the first time that daminozide has the same mode of action as prohexadione in distinct plant species, namely to inhibit the 3β-hydroxylase and, to a lesser extent, the 2β-hydroxylase. This is probably due to the structural similarity of the two inhibitors with 2-oxoglutarate. 相似文献
Further information was obtained from the GC-MS analysis of GAs found in the newly formed parts of the shoots of peanut seedlings treated with the two compounds. Both growth retardants inhibited the formation of GA
These results clearly indicate for the first time that daminozide has the same mode of action as prohexadione in distinct plant species, namely to inhibit the 3β-hydroxylase and, to a lesser extent, the 2β-hydroxylase. This is probably due to the structural similarity of the two inhibitors with 2-oxoglutarate. 相似文献
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Jan G. H. M. Rijnders Young-Yell Yang Yuji Kamiya Nobuta Takahashi Gerard W. M. Barendse Cornelis W. P. M. Blom Laurentius A. C. J. Voesenek 《Planta》1997,203(1):20-25
The role of gibberellin (GA) and ethylene in submergence-induced petiole elongation was studied in two species of the genus
Rumex. Analysis of endogenous GAs in the flooding-tolerant Rumex palustris Sm. and the intolerant Rumex acetosa L. by gas chromatography-mass spectrometry showed for both species the presence of GA1, GA4, GA9, GA19, GA20 and GA53. Gas chromatography-mass spectrometry analysis of R. palustris petiole tissue of submerged plants showed an increase in levels of 13-OH GAs, especially GA1, compared with drained plants. This effect could be mimicked by application of 5 μL L−1 ethylene. In R. acetosa, no differences between levels of GAs in drained or submerged plants were found. In R. palustris, both submergence and ethylene treatment sensitized petioles to exogenous gibberellic acid (GA3). In R. acetosa the effect was opposite, i.e. submergence and ethylene de-sensitized petioles to GA3. Our results demonstrate the dual effect of ethylene in the submergence response related to flooding tolerance, i.e. in the
flooding-tolerant R. palustris ethylene causes an increased concentration of and sensitivity to GA with respect to petiole elongation while in the intolerant
R. acetosa ethylene reduces growth independent of GAs.
Received: 5 November 1996 / Accepted: 8 February 1997 相似文献
14.
Pb and Cd uptake in rice roots 总被引:9,自引:0,他引:9
Pb and Cd are heavy metal pollutants that inhibit plant growth. Using a cultivated rice variety (Dongjin, Oryza sativa L.), we studied how the transport and toxicity of Pb2+ and Cd2+ are affected by the presence of K+ , Ca2+ or Mg2+ . K+ had a little effect on uptake or toxicity of Pb2+ and Cd2+ . Ca2+ or Mg2+ blocked both Cd2+ transport into rice roots and Cd2+ toxicity on root growth, which suggested that their detoxification effect is directly related to their blocking of entry of the heavy metals. Similarly, Ca2+ blocked both Pb2+ transport into the root and Pb2+ toxicity on root growth. The protective effect of Ca2+ on Pb2+ toxicity may be related to its inhibition of the heavy metal accumulation in the root tip, a potential target site of Pb2+ toxicity. Mg2+ did not ameliorate the Pb2+ toxicity on root growth as much as Ca2+ did, although it decreased Pb2+ uptake into roots similarly as Ca2+ did. These results suggest that the protective effect of Ca2+ on Pb2+ toxicity may involve multiple mechanisms including competition at the entry level, and that Pb2+ and Cd2+ may compete with divalent cations for transport into roots of rice plants. 相似文献
15.
Yang Young-Yell; Yamaguchi Isomaro; Takeno-Wada Kiyotoshi; Suzuki Yoshihito; Murofushi Noboru 《Plant & cell physiology》1995,36(2):221-227
Gibberellin A1, (GA1), GA19, and GA20 in phloem exudates andcotyledons of seedlings of Pharbitis nil cv. Violet, grown underdifferent photoperiodic conditions, were qualitatively and semi-quantitativelyanalyzed by a combination of high performance-liquid chromatography(HPLC) and radioimmunoassays (RIA). The levels of GA19 and GA20were higher in cotyledons from plants grown under dark treatment(DT) conditons of 16 h-light/8 h-dark for 6 days followed by8 h-light/16 h-dark for 3 days than in those grown under continuouslight (CL) for 9 days. This relationship was also observed forthe GAs in phloem exudates, although the levels were much lowerthan in the cotyledons. When GAs were applied to the cotyledons,elongation of the epicotyl was promoted more by GA20 than byGA1 or GA19, especially under the CL treatment. The relativeeffect of GA1 and GA20 on the epicotyl elongation was reversedwhen these GAs were applied to epicotyls pre-treated with prohexadione,an inhibitor of 2-oxoglutarate-dependent dioxygenases.
3Present address: Frontier Research Program, The Institute ofPhysical and Chemical Research (RIKEN), 2-1 Hirosawa, Wakoshi,Saitama, 351-01 Japan
4Present address: Laboratory of Horticulture, Faculty of Agriculture,Nagoya University, Nagoya, 464-01 Japan 相似文献
16.
Gawronska Helena; Yang Young-Yell; Furukawa Koji; Kendrick Richard E.; Takahashi Nobutaka; Kamiya Yuji 《Plant & cell physiology》1995,36(7):1361-1367
Using gas chromatography-selected ion monitoring with internalstandards we analyzed endogenous levels of GA1, GA8, GA19, GA20,GA29, GA44 and GA53 in shoots of pea cv. Alaska grown underdifferent levels of irradiance: high irradiance, 386±70µmolm-2s-1, control (100%); medium (50%); low (10%); darkness (0%).The average plant heights for medium and low irradiance anddark grown plants were 157%, 275%, and 460% of the control plants,respectively. Plants grown in medium and low irradiance developedthe same numbers of internodes as control plants but plantsin darkness developed fewer internodes and exhibited suppressedleaf expansion. The endogenous levels of GA1 GA8 and GA29 werehigher in medium and low irradiance grown plants than thoseof the high irradiance control. In particular, the GA20 levelof low irradiance plants was markedly higher (7.6-fold) thanthat of control plants. In dark-grown plants GA1, and GA8 levelsalso slightly increased but GA20 and GA29 levels decreased andthe levels of GA19, GA44 and GA53 did not change. Feeding ofGA1, and a GA biosynthesis inhibitor (uniconazole) to plantsgrown at reduced irradiance and in darkness suggests that theresponsiveness of plants to GA1, also increased at low irradianceand in darkness. In conclusion, plants increase both GA1, andGA20 biosynthesis or altered catabolism and GA1, responsivenessunder low irradiance stress
1Present address: Dept. of Plant Physiol., Warsaw AgriculturalUniversity, Rakowiecka 26-30, 02-528 Warsaw, Poland 相似文献