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1.
Eight cytokinins detected in germinated chick-pea (Cicer arietinum L. var. Castellana) seeds were first present in the embryonic axes but appeared in the cotyledons after 12h of germination. The cytokinins detected in the cotyledons originate in the embryonic axes, but no passage of these substances from the cotyledons to the axes was detected, except when the seeds were treated with red light.It is concluded that the role played by the embryonic axis in mobilizating the main reserves of the cotyledons is mainly effected through these cytokinins. Both natural and synthetic cytokinins exert an important regulatory role in the hydrolysis of reserve proteins and calcium could be involved as an intermediate.Abbreviations BA
benzyladenine
- cot.
cotyledon
- (diH)Z
dihydrozeatin
- (diH)ZR
dihydrozeatin riboside
- GZR
glycosyl zeatin riboside
- 2iP
277-1
- iPA
277-2 riboside
- Kin
kinetin
- Z
zeatin
- ZG
zeatin glucoside
- ZR
zeatin riboside 相似文献
2.
Endogenous hormonal content and somatic embryogenic capacity of Corylus avellana L. cotyledons 总被引:2,自引:0,他引:2
Endogenous indole-3-acetic acid (IAA), abscisic acid (ABA) and cytokinins [zeatin (Z) zeatin riboside, dihydrozeatin, dihydrozeatin
riboside, N6-isopentenyl adenine (iP) and N6-isopentenyladenine riboside] were evaluated in hazelnut (Corylus avellana L.) cotyledons of different developmental stage and genetic source for their somatic embryogenic capacity. There was an inverse
correlation between the embryogenic potential of cotyledons and the degree of maturity of zygotic embryos, the first characteristic
being associated with iP-type cytokinins and the second with Z-type cytokinins. Although the differences in total cytokinin,
ABA and IAA contents between the cotyledons were small, the IAA/ABA and, mainly, the iP-type/Z-type cytokinin ratios were
found to be two good indexes of the embryogenic competence of explants, suggesting that the endogenous hormonal balance is
a very important factor defining the in vitro potential of hazelnut cotyledons.
Received: 6 January 1997 / Revision received: 3 March 1997 / Accepted 1 April 1997 相似文献
3.
High performance liquid chromatography analysis of immunoaffinity-purified extracts of mycelia of Amanita muscaria, and the Amaranthus bioassay of the eluted fractions, revealed the following seven cytokinins: zeatin, zeatin riboside, zeatin N-9-glucoside, dihydrozeatin, dihydrozeatin riboside, isopentenyl adenine, and isopentenyl adenosine. The decreased growth of aluminum-treated mycelia correlated with a 35% decrease in the total amount of the cytokinins. Among individual cytokinins, zeatin was the most affected, exhibiting a reduction of about 90%. The results are compared with previous investigations of aluminum effects on cytokinins in the mycelia of Lactarius piperatus, whose growth is stimulated by aluminum.Abbreviations ZR
zeatin riboside
- iPA
isopentenyl adenosine
- Z
zeatin
- DHZ
dihydrozeatin
- iP
isopentenyl adenine
- DHZR
dihydrozeatin riboside
- Z-9G
zeatin N-9-glucoside
- iP-9G
isopentenyl N-9-glucoside
- HPLC
high performance liquid chromatography
- DHZRMP
dihydrozeatin riboside monophosphate
- ZRMP
zeatin riboside monophosphate 相似文献
4.
Cultured crown gall tissue of Vinca rosea L. was found to contain, in addition to the previously reported cytokinins zeatin, zeatin riboside, and the 0-glucosides of these two compounds, relatively high levels of zeatin-9-D-glucopyranoside. This is the first conclusive identification of an endogenous cytokinin 9-glucoside.Abbreviations GC
gas chromatography
- HPLC
high-performance liquid chromatography
- I.D.
internal diameter
- RFE
rotary film evaporation
- TLC
thin layer chromatography
- TMS
trimethylsilyl
- UV
ultraviolet
- Z
zeatin
- Z7G
zeatin-7-glucoside
- Z9G
zeatin-9-glucoside
- Z0G
zeatin-0-glucoside
- ZR
zeatin riboside
- ZR0G
zeatin riboside-0-glucoside 相似文献
5.
S. J. H. Rizvi V. Rizvi D. Mukerji S. N. Mathur 《Journal of Plant Growth Regulation》1984,3(1-4):237-244
The effects of some nodular cytokinis, zeatin (Z), zeatin riboside (ZR), N6 (Δ2-isopentenyl) adenine (IPA), and N6 (Δ2-isopentenyI) adenosine (IPAS) on nitrate reductase (E.C 1.9.6.1) activity of root nodules ofPhaseolus mungo were investigated. The cytokinis were also tested for their effect on nitrate uptake by nodules. The results show that IPAS is the most effective of all the four cytokinins tested. Z and IPA, which caused higherin vivo activity than ZR and IPAS, stimulated uptake of nitrate by nodules. The other two (ZR and IPAS) while inhibiting uptake showed greaterin vitro activity than Z and IPA. It may be concluded that some cytokinins, in addition to their direct effects on the enzyme, may increase the substrate availability to it, whereas others may have only an direct effect on the enzyme activation or degradation. 相似文献
6.
BA(benzyl adenine)专一性地促进离体黄瓜子叶的扩张。为了研究 BA 的作用机理,我们采用间接 EIISA 和 HPLC 的方法测定了子叶扩张过程中内源玉米素(Z)和玉米素核苷(ZR)含量的变化。离体黄瓜(Cucumis sativus,津研4号)子叶用10mg/l 的 BA 培养,72小时之后,处理子叶鲜重的增加比对照高70%。Z+ZR 在 BA 处理的子叶中有大量的积累。结果表明 BA 可能诱发了黄瓜子叶中的细胞分裂素生物合成和代谢的某些基因。 相似文献
7.
Qualitative and quantitative differences in cytokinin levels of gram seeds were observed during germination of control and
6-benzylaminopurine (BAP; 4.44 x 10t-5 M) treated seeds. Zeatin riboside (ZR), zeatin (Z), dihydrozeatin (DHZ), isopentenyladenosine (iPA) and isopentenyladenine
(iP) were determined using high pressure liquid chromatography. In the control seeds the ZR content increased markedly only
after 24 h of germination. In BAP treated seeds, the increase in ZR content was stronger than in control seeds and it persisted
during further germination. Z content increased during germination in both control and treated seeds. After 48 h of germination
iP appeared in control and especially in treated seeds.
Acknowledgements: The senior author is thankful to University Grants Commision, New Delhi for award of Research Associateship. 相似文献
8.
Sonali P. Barwe Muthukrishnan Sathiyabama Chelliah Jayabaskaran 《Journal of plant physiology》2001,158(1)
Cotyledons were excised from 7-day-old dark-grown cucumber seedlings and treated with water, benzyladenine (BA), kinetin (K), zeatin (Z), or zeatin riboside (ZR) in dark after endogenous cytokinin depletion. We have compared changes in chitinase (EC. 3.2.1.14) activity induced by these cytokinins. We find that the activities of chitinase and its isoforms increase by approximately 3- to 6-fold following BA, Z, and ZR treatments. Among these treatments, Z was more effective. K was totally ineffective in inducing chitinase activity. Immunoblot analysis suggests that the cytokinin Z-induction of enzyme activity is due to the induction of higher chitinase protein levels and not the activation of existing enzyme. Furthermore, the Z-induced chitinase activity and its protein accumulation were completely inhibited by the protein kinase inhibitor staurosporine, whereas the protein phosphatase inhibitor sodium fluoride was not effective in such inhibitions. Treatment of cotyledons with extemal CaCl2 and calcium ionophore increased the basal chitinase activity by 6- and 5-fold, respectively. Moreover, the effects of staurosporine, sodium fluoride, and Ca2+ on Z-induced chitinase activity correlate with their effects on chitinase protein levels. Taken together, our data suggests Ca2+ and staurosporine-sensitive protein kinase(s) as components of the cytokinin transduction machinery involving induction of chitinase in cucumber. 相似文献
9.
Organogenesis in thin cell layers of Nicotiana tabacum L. was studied in relation to the effects of natural and synthetic auxins in combination with various cytokinins. All cytokinins tested, benzyladenine (BA), kinetin, zeatin (Z), zeatin riboside (ZR), N6 -Δ2 -isopentenyl) adenine (IPA), dihydrozeatin [(diH)Z] and dihydrozeatin riboside [(diH)ZR], seem to be active in flower bud formation. In addition to the initiation of flower buds, vegetative buds or roots were also formed on the explants in the presence of BA, Z or IPA as exogenous cytokinins. Only dihydrozeatin and its riboside stimulated the initation of flower buds alone (as is known for kinetin), especially if supplemented with indole-3-acetic acid (IAA) as exogenous auxin. A high number of explants with flower buds was also found with high cytokinin/2,4-D ratios. In these conditions the presence of (diH)Z yielded the higest number of flower buds per explant. 相似文献
10.
Influence of Different Cytokinins on the Germination of Lettuce (Lactuca sativa) and Celery (Apium graveolens) Seeds 总被引:1,自引:0,他引:1
The naturally occurring cytokinins, zeatin, zeatin riboside and dihydrozeatin did not promote the germination of celery (Apium graveolens L.) seeds and 6-Δ2-isopentenyladenine (2iPA) and its riboside were only moderately active. Of the synthetic cytokinins, kinetin, kinetin riboside, and the disubstituted urea, N-phenyl-N′-pyridyl urea (NC5392) were moderately active, and 6-benzyl-aminopurine (BA) and its derivatives BA riboside and 6-benzyl-amino-9(tetrahydropyran-2yl)purine (SD8339) were the most active cytokinins tested. 6-(o-hydroxybenzyl)aminopurine (hyd-BA) and its naturally occurring riboside inhibited germination under normally inductive conditions. All the cytokinins examined were more active in promoting germination of lettuce (Lactuca sativa L.) than celery seeds. BA, BA riboside and SD8339 were again the most active cytokinins. In contrast to the results with celery, zeatin and zeatin riboside were highly active. The other cytokinins also showed high activity with the exception of dihydrozeatin, hyd-BA and hyd-BA riboside which were less active. Cytokinin ribosides were less active than the corresponding free bases during the early period of the lettuce seed incubation but total germination after 90 h was similar. 相似文献
11.
12.
the cytokinins of tobacco crown-gall tissue have been analysed by quantitative mass spectrometry using 2H2-labelled cytokinin riboside 5-monophosphates and 15N4-labelled cytokinin glycosides as internal standards. The principal endogenous cytokinin of this tissue is zeatin riboside 5-monophosphate. The biologically inactive 7-glucoside of zeatin is the most abundant basic cytokinin in the tissue. These findings expose the limitations of previously reported analyses of similar tissues, which were restricted to biologically active basic cytokinins. The present study demonstrates that the endogenous cytokinins of tobacco crowngall tissue show a clear correspondence to the range of metabolites formed when exogenous cytokinins are supplied to nontumorous tobacco cells.Abbreviations DHZ
dihydrozeatin
- DHZ7G
dihydrozeatin 7-glucoside
- DHZMP
dihydrozeatin 9-riboside 5-monophosphate
- DHZR
dihydrozeatin 9-riboside
- GC-MS
coupled gas chromatography-mass spectrometry
- HPLC
high-performance liquid chromatography
- Z7G
zeatin 7-glucoside
- Z9G
zeatin 9-glucoside
- ZOG
zeatin O-glucoside
- ZMP
zeatin 9-riboside 5-monophosphate
- ZR
zeatin 9-riboside
- ZROG
zeatin 9-riboside O-glucoside 相似文献
13.
The activity, uptake and metabolism of cytokinin metabolites was determined in soybean (Glycine max (L.) Merr.) callus tissue. The following activity sequence was established: zeatin riboside (ZR)>zeatin (Z)>O-glucosides of Z, ZR and their dihydro derivatives>lupinic acid (an alanine conjugate of Z)>7- and 9-glucosides of Z which were almost inactive. The 7- and 9-glucosides and lupinic acid were taken up very slowly by the callus tissue and showed great metabolic stability, but some degradation to 7-glucosyladenine, 9-glucosyladenine and the 9-alanine conjugate of adenine occurred. Compared with its aglycone, O-glucosyl-ZR exhibited slow uptake and greatly enhanced stability but gas chromatographic-mass spectrometric analysis showed that appreciable amounts were hydrolyzed to ZR in the tissue. Both ZR and O-glucosyl-ZR were metabolised extensively, with adenine, adenosine, and adenine nucleotide(s) as the major metabolites. A diversity of minor metabolites of ZR were identified, including O-glucosides, lupinic acid and dihydrolupinic acid. The metabolism of ZR was suppressed by 3-isobutyl-1-methylxanthine. When compared with the soybean callus line normally used for cytokinin bioassays (cv. Acme, cotyledonary callus), related callus lines exhibited greatly differing growth responses to cytokinin: however, these were not reflected in marked differences in metabolism.Abbreviations GC-MS
gas chromatography-mass spectrometry
- HPLC
high-performance liquid chromatography
- LA
lupinic acid
- OGZR
O--D-glucopyranosylzeatin riboside
- TLC
thin-layer chromatography
- IMX
3-isobutyl-1-methylxanthine
- Z
zeatin
- ZR
zeatin riboside 相似文献
14.
S. J. H. Rizvi V. Rizvi D. Mukerji S. N. Mathur 《Journal of Plant Growth Regulation》1984,3(1-3):237-244
The effects of some nodular cytokinis, zeatin (Z), zeatin riboside (ZR), N6 (2-isopentenyl) adenine (IPA), and N6 (2-isopentenyI) adenosine (IPAS) on nitrate reductase (E.C 1.9.6.1) activity of root nodules ofPhaseolus mungo were investigated. The cytokinis were also tested for their effect on nitrate uptake by nodules. The results show that IPAS is the most effective of all the four cytokinins tested. Z and IPA, which caused higherin vivo activity than ZR and IPAS, stimulated uptake of nitrate by nodules. The other two (ZR and IPAS) while inhibiting uptake showed greaterin vitro activity than Z and IPA. It may be concluded that some cytokinins, in addition to their direct effects on the enzyme, may increase the substrate availability to it, whereas others may have only an direct effect on the enzyme activation or degradation.Deceased. 相似文献
15.
Niels Bredmose Kell Kristiansen Rikke Nørbæk Lars P. Christensen Jens Hansen-Møller 《Journal of Plant Growth Regulation》2005,24(3):238-250
Involvement of cytokinins (CKs) in axillary bud growth of miniature rose was studied. Variation in root formation and axillary
bud growth was induced by two indole 3-butyric acid (IBA) pretreatments in two cutting sizes. At six physiological developmental
stages around the onset of axillary bud growth, concentrations of CKs were determined in both root and axillary bud tissue
by liquid chromatography combined with electrospray tandem mass spectrometry (LC-ESP-MS/MS). Chronological early onset of
axillary bud growth occurred in long cuttings pretreated at low IBA concentration, whereas physiological early root formation
was associated with long cuttings and high IBA concentration. The CKs zeatin (Z), isopentenyl adenine (iP), zeatin riboside
(ZR), dihydrozeatin riboside (DHZR), isopentenyl adenosine (iPA), zeatin O-glucoside (ZOG), zeatin riboside O-glucoside (ZROG), zeatin riboside 5′-monophosphate (ZRMP), and isopentenyl adenosine 5′-monophosphate (iPAMP) were detected. Concentrations of CKs in axillary bud tissue far exceeded those in root tissue. Indole
3-butyric acid pretreatment influenced the concentration of CKs in axillary bud tissue more than did cutting size, whereas
pretreatments only slightly affected CKs in root tissue. The dominant CKs found were iPAMP and ZR. An early and large increase
in iPAMP indicated rapid CK biosynthesis in rootless cuttings, suggesting that green parts, including the axillary bud, can
synthesize CKs. At the onset of axillary bud growth an increase in concentration of Z, ZR, ZRMP, ZOG, and ZROG was largely
coincident with a decrease in iPAMP, iPA, iP, and DHZR. After the onset of axillary bud growth, CK content largely decreased.
These results strongly indicate a positive role for CKs in axillary bud growth, and presumably ZRMP, ZR, and Z are active
in miniature rose. 相似文献
16.
Data are presented on the cytokinin status of seeds and seed components, at different stages of development in Phaseolus coccineus L., as determined with the soybean callus growth bioassay: A change in cytokinin types according to developmental stage occurred: from biologically very active less polar types (zeatin=Z) at early stages to more polar types (zeatin glucoside=Z9G and zeatin riboside=Zr), with relatively low biological activity, at intermediate and late stages of seed development: When cytokinins were analyzed separately in embryos (embryo proper) and suspensors at two embryonic stages: heart-shaped (A) and middle cotyledonary embryos (stage B) respectively, it was found that: i) at stage A, the suspensor showed cytokinin activity at the level of Z, 2iPA (2-isopentenyladenosine) and Zr, whereas more polar cytokinins (Z9G, Zr) were present in the embryo; ii) at stage B, when the embryo seems to become autonomous for cytokinin supply, there was a relative abundance of active cytokinins (Z, 2iPA) in the embryo to which Z9G activity in the suspensor corresponded. It is concluded that the suspensor plays an essential role in embryogenesis by acting as a hormone source to the early embryo.Abbreviations GA
gibberellic acid
- 2iPA
2-isopentenyladenosine
- Stage A
heart-shaped embryo
- siage B
middle cotyledonary embryo
- Z
zeatin
- Z9G
zeatin glucoside
- Zr
Zeatin riboside 相似文献
17.
Dihydrozeatin riboside has been identified in the leaves of decapitated bean plants by Sephadex LH20 chromatography and combined gas chromatography-mass spectrometry. The relationship between the cytokinins isolated and identified from this system and those previously reported in Phaseolus is discussed.Abbreviations DHZ
dihydrozeatin
- DHZOG
dihydrozeatin-O--D-glucoside
- DHZR
dihydrozeatin riboside
- GCMS
combined gas chromatography-mass spectrometry
- GLC
gas-liquid chromatography
- TIC
total ion current
- TMS
trimethylsilyl
- Z
zeatin
- ZR
zeatin riboside 相似文献
18.
Influence of Endogenous Cytokinins on Reverse Mobilization in Cotyledons of Cicer arietinum L: Reproduction of Endogenous Levels of Total Cytokinins, Zeatin, Zeatin Riboside, and Their Corresponding Glucosides 下载免费PDF全文
The embryonic axis plays an essential role in the mobilization of the main reserves of the cotyledons of seeds of Cicer arietinum L. cv Castellana. This control by the axis of the metabolism of the storage products of the cotyledons largely takes place through the cytokinins, which are transported from the embryonic axis to the cotyledons where the mobilization of reserves begins. The principal regulatory role of the endogenous cytokinins concerns the metabolism of carbohydrates and proteins; there is less influence on lipid metabolism. However, each cytokinin seems to have a different role in the mobilization processes. The glucosides, glucosyl zeatin riboside, and glucosyl zeatin act only as storage forms of the hormones. Zeatin riboside affects mainly the mobilization of carbohydrates and has less effect on protein mobilization. Zeatin regulates both the mobilization of carbohydrates and that of proteins and is more marked in the latter case. 相似文献
19.
Wendy A. Stirk Kate?ina Václavíková Ond?ej Novák Silvia Gajdo?ová Ond?ej Kotland Václav Motyka Miroslav Strnad Johannes van Staden 《Journal of Plant Growth Regulation》2012,31(3):392-405
The aims of this study were to monitor endogenous cytokinin levels during germination and early seedling establishment in oats, maize, and lucerne to determine which cytokinin forms are involved in these processes; to quantify the transfer ribonucleic acid (tRNA)-bound cytokinins; and to measure cytokinin oxidase/dehydrogenase (CKX) activity. Cytokinins were identified using UPLC-MS/MS. The predominant free cytokinins present in the dry seeds were dihydrozeatin-type (DHZ) in lucerne and maize and cZ-type (cis-zeatin) in oats. Upon imbibition, there was a large increase in cZ-type cytokinins in lucerne although the cZ-type cytokinins remained at high levels in oats. In maize, the high concentrations of DHZ-type cytokinins decreased prior to radicle emergence. Four tRNA-bound cytokinins [cis-zeatin riboside (cZR)>N 6-(2-isopentenyl)adenosine (iPR), dihydrozeatin riboside (DHZR), trans-zeatin riboside (tZR)] were detected in low concentrations in all three species investigated. CKX activity was measured using an in vitro radioisotope assay. The order of substrate preference was N 6-(2-isopentenyl)adenine (iP)>trans-zeatin (tZ)>cZ in all three species, with activity fluctuating as germination proceeded. There was a negative correlation between CKX activity and iP concentrations and a positive correlation between CKX activity and O-glucoside levels. As O-glucosides are less resistant to CKX degradation, they may provide a readily available source of cytokinins that can be converted to physiologically active cytokinins required during germination. Aromatic cytokinins made a very small contribution to the total cytokinin pool and increased only slightly during seedling establishment, suggesting that they do not play a major role in germination. 相似文献
20.
Changes in phytohormone contents in chickpea seeds germinating under lead or zinc stress 总被引:5,自引:0,他引:5
The present work describes the changes that take place in phytohormone contents in germinating chickpea (Cicer arietinum cv. Aziziye-94) seeds in response to heavy metal stress. For this aim, endogenous abscisic acid (ABA), gibberellic acid (GA3), zeatin (Z) and zeatin riboside (ZR) contents were followed for 24, 48 and 72 h in chickpea seeds germinating at the concentrations of 0.1, 1.0 and 5.0 mM Pb or 0.1, 1.0 and 10 mM Zn. The results showed that Pb and Zn significantly delayed and impeded the germination of chickpea seeds. The negative effect of Pb on germination was higher than that of Zn. Further, Pb increased ABA and Z contents while decreased GA3 content in the germinating seeds. The high concentrations of Zn (1.0 and 10 mM) decreased contents of Z, ZR and GA3 while 0.1 mM Zn increased the content of the same hormones. The ABA content was enhanced by Zn in all concentrations used. 相似文献