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1.
Maize roots (Zea mays, cv. DK 626) growing in aerated solutions showed striking variations in the amount of ethylene produced during different
stages of development. As endogenous ethylene increases, root elongation decreases. Exogenous 1-aminocyclopropane-1-carboxylic
acid (ACC) supplied to these roots also inhibited their elongation and increased both the fresh weight of the apex and the
ethylene produced. The inhibitor of ethylene biosynthesis, 2-aminoethoxyvinyl glycine (AVG), and the inhibitor of ethylene
action, silver thiosulfate (STS), also reduced growth and increased swelling. As growth diminishes at reduced ethylene concentrations
or with impeded ethylene action, these results support the view that ethylene is necessary for root growth. As ACC treatment
also inhibited root elongation, it appears that ethylene was inhibitory at both low and high concentrations. Whereas ACC stimulated
ethylene production 4 h after the beginning of treatment, inhibition of root elongation and promotion of fresh weight advanced
slowly and needed 24 h to be established. At that time, root elongation reached a maximum response of 60% inhibition and 50%
increase in weight. At 48 h, higher doses of ACC were required to provoke the same response as at 24 h. This suggests that
the root growth progressively accomodates to higher ethylene concentrations.
Published in Russian in Fiziologiya Rastenii, 2009, Vol. 56, No. 4, pp. 539–545.
This text was submitted by the authors in English. 相似文献
2.
We have previously shown that both endogenous auxin and ethylenepromote adventitious root formation in the hypocotyls of derootedsunflower (Helianthus annuus) seedlings. Experiments here showedthat promotive effects on rooting of the ethylene precursor,1-aminocyclopropane-l-carboxylic acid (ACC) and the ethylene-releasingcompound, ethephon (2-chloro-ethylphosphonic acid), dependedon the existence of cotyledons and apical bud (major sourcesof auxin) or the presence of exogenously applied indole-3-aceticacid (IAA). Ethephon, ACC, aminoethoxyvinylglycine (an inhibitorof ethylene biosynthesis), and silver thiosulphate (STS, aninhibitor of ethylene action), applied for a length of timethat significantly influenced adventitious rooting, showed noinhibitory effect on the basipetal transport of [3H]IAA. Theseregulators also had no effect on the metabolism of [3H]IAA andendogenous IAA levels measured by gas chromatography-mass spectrometry.ACC enhanced the rooting response of hypocotyls to exogenousIAA and decreased the inhibition of rooting by IAA transportinhibitor, N-1-naphthylphthalamic acid (NPA). STS reduced therooting response of hypocotyls to exogenous IAA and increasedthe inhibition of rooting by NPA. Exogenous auxins promotedethylene production in the rooting zone of the hypocotyls. Decapitationof the cuttings or application of NPA to the hypocotyl belowthe cotyledons did not alter ethylene production in the rootingzone, but greatly reduced the number of root primordia. We concludethat auxin is a primary controller of adventitious root formationin sunflower hypocotyls, while the effect of ethylene is mediatedby auxin. Key words: Auxin, ethylene, adventitious rooting, sunflower 相似文献
3.
Interaction of ethylene with indole-3-acetic acid in regulation of rooting in pea cuttings 总被引:1,自引:0,他引:1
Cuttings of pea (Pisum sativum L. cv Marma) were treated with 1-aminocyclopropane-l-carboxylic acid (ACC). This treatment caused increased ethylene production and reduction of root formation. The effect of 0.1 mM ACC on the level of endogenous indole-3-acetic acid (IAA) in the rooting zone and in the shoot apex was analyzed by gas chromatography-single ion monitoring mass spectrometry or by high pressure liquid chromatography with fluorimetric detection (HPLC). Concentrations of indole-3-acetylaspartic acid (IAAsp) in the stem bases were also determined using HPLC. The ACC treatment had little effect on the IAA level in the base measured after 24 h, but caused a considerable decrease during the 3 following days. IAAsp increased in the base on days 1, 2 and 3 and then declined. The build up of IAAsp in the base was not affected by ACC during the first two days of the treatment, but later this conjugate decreased more rapidly than in controls. No effect of the ACC treatment was found on the level of IAA in the apex. IAA (1 µM) applied to the cuttings during 24 h reduced the number of roots formed. The possibility that IAA-induced ethylene is involved in this response was investigated.Our results support earlier evidence that the inhibitory effect of ethylene on rooting in pea cuttings is due to decreased IAA levels in the rooting zone. The inhibitory effect of applied IAA is obtained if the internal IAA level is maintained high during the first 24 h, whereas stimulation of rooting occurs if the internal IAA level remains high during an extended period of time. Our results do not support the suggestion that ethylene mediates the inhibitory effect of applied IAA. 相似文献
4.
Gyana Ranjan Rout 《Plant Growth Regulation》2006,48(2):111-117
An attempt was made to induce rooting from single node cuttings of Camellia sinensis var. TV-20 under controlled conditions and study its biochemical changes during rooting. The nodal cuttings were pretreated
with different concentrations of IAA, NAA and IBA and kept in a growth chamber (25 ±2 °C, 16 h photoperiod (55 μ mol m−2 s−1) with cool, white fluorescent lamps and 65% relative humidity) for 12 h. Among the three auxins used for pretreatment, IBA
showed more positive response on rooting as compared to IAA and NAA within 2 weeks of transfer to potting medium. Among four
concentrations of IBA tested, 75 ppm gave maximum percentage of rooting, number of roots and root length. Therefore, IBA was
used further in experiments for biochemical investigation. The adventitious rooting was obtained in three distinct phases
i.e. induction (0–12 days), initiation (12–14 days) and expression (14–18 days). IAA-oxidase activity of IBA-treated cuttings
increased slightly as compared to control. The activity was found to decrease during induction and initiation phases and increase
during expression phase. The peroxidase activity in IBA-treated cuttings increased up to initiation phase and declined at
the expression phase. Polyphenoloxidase activity increased both in IBA-treated and control cuttings during induction and initiation
phase but declined slowly during expression phase. Total phenolic content was higher in IBA-treated cuttings, particularly
in initiation and expression phases and it also correlated with peroxidase activity. Phenolics might be playing key role for
induction of adventitious rooting, and phenolic compounds can be used as rooting enhancer in tea plant. 相似文献
5.
A. Ptak A. El. Tahchy G. Wyżgolik M. Henry D. Laurain-Mattar 《Plant Cell, Tissue and Organ Culture》2010,102(1):61-67
The influence of ethylene on in vitro morphogenesis of Leucojum aestivum and galanthamine accumulation was studied. Calli were cultivated on Murashige and Skoog (MS) medium supplemented with 25 μM
4-amino-3,5,6-trichloropicolinic acid (picloram) and 0.5 μM benzyladenine (BA). During incubation under these conditions,
callus cultures produced ethylene (9.5 nL/g fresh weight: F.W.) whereas no ethylene was found in somatic embryos cultivated
on medium supplemented with 0.5 μM α-naphthalene acetic acid (NAA) and 5 μM zeatin. Application of the precursor of ethylene
1-aminocyclopropane-1-carboxylic acid (ACC) increased ethylene production in both cultures, and decreased callus growth by
a factor of 1.2, whereas callus growth was enhanced by a factor of 1.1 in the presence of an inhibitor of ethylene silver
nitrate (AgNO3) or by a factor of 1.2 with an absorbent potassium permanganate (KMnO4). ACC enhanced the induction of somatic embryos and the development of globular embryos. Removal of ethylene by KMnO4 during somatic embryogenesis led to the development of plants with greater length. Silver thiosulphate (STS) induced galanthamine
production in callus cultures (0.1% dry weight), whereas ACC induced galanthamine production in somatic embryo cultures (2%
dry weight). 相似文献
6.
Rita Barreto Jorge Nieto-Sotelo Gladys I. Cassab 《Plant Cell, Tissue and Organ Culture》2010,103(1):93-101
Agave tequilana Weber var. Azul plants reproduce asexually by producing ramets. Continuous production of ramets throughout the vegetative
cycle of the parent delays the time of harvesting of heads for tequila production. Little is known about the factors influencing
their emergence. Heads are engrossed rosettes where fructans are stored. We show here that, in plantlets grown in vitro, growth
regulators such as 2,4-dichlorophenoxyacetic acid (2,4-D), a combination of 1-naphthaleneacetic acid (NAA)/6-benzyladenine
(BA), or abscisic acid (ABA) increased the production of ramets, whereas BA, NAA, gibberellic acid (GA3), glycerol, or a combination of glycerol/ABA decreased ramet production. Plantlets that developed ramets did not form heads.
Head formation was improved on solid media in the presence of BA, NAA, the ethylene precursor 1-aminocyclopropane-1-carboxylic
acid (ACC), or the water stress inducer polyethylene glycol (PEG). Basal Murashige–Skoog (MS) liquid media also enhanced rosette
engrossment, which was further increased by addition of ACC or PEG. In contrast, CoCl2, an ethylene biosynthesis inhibitor, reduced rosette engrossment. Furthermore, heads from A. tequilana plantlets grown in tissue culture in MS media, or in MS media supplemented with NAA, ACC or PEG, showed fructan concentrations
10–30 times higher than in leaves from greenhouse-grown plants. Our results indicated that BA, NAA, water stress, and ethylene
are critical regulators of rosette engrossment, whereas asexual reproduction in A. tequilana seems to be controlled by a complex hormonal network. 相似文献
7.
Dormancy removal in apple embryos by nitric oxide or cyanide involves modifications in ethylene biosynthetic pathway 总被引:1,自引:0,他引:1
The connection between classical phytohormone-ethylene and two signaling molecules, nitric oxide (NO) and hydrogen cyanide
(HCN), was investigated in dormancy removal and germination “sensu stricto” of apple (Malus domestica Borkh.) embryos. Deep dormancy of apple embryos was removed by short-term (3–6 h) pre-treatment with NO or HCN. NO- or HCN-mediated
stimulation of germination was associated with enhanced emission of ethylene by the embryos, coupled with transient increase
in ROS concentration in embryos. Ethylene vapors stimulated germination of dormant apple embryos and eliminated morphological
anomalies characteristic for young seedlings developed from dormant embryos. Inhibitors of ethylene receptors completely impeded
beneficial effect of NO and HCN on embryo germination. NO- and HCN-induced ethylene emission by apple embryo was only slightly
reduced by inhibitor of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase activity during first 4 days of germination. Short-term pre-treatment of
the embryos with NO and HCN modified activity of both key enzymes of ethylene biosynthetic pathway: ACC synthase and ACC oxidase.
Activity of ACC synthase declined during first 4 days of germination, while activity of ACC oxidase increased markedly at
that time. Additional experiments point to non-enzymatic conversion of ACC to ethylene in the presence of ROS (H2O2). The results indicate that NO and HCN may alleviate dormancy of apple embryos “via” transient accumulation of ROS, leading
to enhanced ethylene emission which is required to terminate germination “sensu stricto”. Therefore, ethylene seems to be
a trigger factor in control of apple embryo dormancy removal and germination. 相似文献
8.
Vespasiano Borges Paiva Neto Luciano B. Reis Fernando L. Finger Raimundo S. Barros Carlos R. Carvalho Wagner C. Otoni 《In vitro cellular & developmental biology. Plant》2009,45(6):693-700
Using seedlings derived from the shoot apex of annatto (Bixa orellana L. cv. Bico-de-Pato) we observed the rooting frequency of B. orellana, the number and length of roots and the rate of ethylene production during 30 d in culture. The rhizogenesis response was
affected by auxins (NAA or IBA) and by both the ethylene biosynthesis precursor 1-aminocyclopropane-1-carboxylic acid (ACC)
and the inhibitor 2-aminoethoxyvinylglycine (AVG). Auxin supplementation to the medium resulted in root induction, ethylene
production, and an undesirable callusing in the epidermal and cortical tissues. Irrespective of the presence of auxins, supplementing
the medium with ACC promoted ethylene biosynthesis and callusing, which resulted in increased cell proliferation mainly in
the cortical and vascular tissues, while the epidermis was mostly unaltered. In both ACC and auxin-supplemented medium, increased
ethylene production and callusing occurred, suggesting a synergistic effect between these two responses. ACC was capable of
inducing adventitious root formation, but the roots produced had a wrinkled appearance when compared to normal roots. Conversely,
AVG reduced ethylene production and callusing, while the epidermis, cortex, and inner tissues remained unaltered, regardless
of the presence of auxins. AVG was beneficial in these aspects, although its application led to a reduction in the number
of roots and in the average root length. In conclusion, it was not possible to establish a direct relation between ethylene
and rooting, but we hypothesize that, under the experimental conditions described, ethylene may enhance tissue sensitivity
to auxin. However, ethylene did not seem essential to the rhizogenesis process in annatto. 相似文献
9.
The role of ethylene in adventitious root formation and its involvement in auxin-induced rooting were investigated in cuttings ofVigna radiata (L.). Treatment with 30 M indole-3-acetic acid (IAA) for 24 h slightly inhibited rooting, whereas the same concentration of indole-3-butyric acid (IBA) significantly stimulated it. Ethylene derived from 1-aminocyclopropane-1-carboxylic acid (ACC) increased the number of adventitious roots but inhibited their emergence and elongation. Endogenous levels of ethylene, ACC, and malonyl-ACC (MACC) were initially higher in cuttings treated with IAA. This trend was quickly reversed, and cuttings, particularly hypocotyls, treated with IBA produced higher levels of ethylene and had more ACC and MACC during most of the rooting process. Aminoethoxyvinylglycine significantly inhibited rooting, but its inhibitory effect could not be reversed by ACC. The data suggest that the stimulating effect of IBA on rooting is closely associated with its induction of ACC and ethylene biosynthesis. 相似文献
10.
Geert-Jan de Klerk Jana Hanecakova Jan Jásik 《Plant Cell, Tissue and Organ Culture》2008,95(3):285-292
We have examined the effect of medium-pH on rooting using 1-mm slices cut from stems of apple microshoots. Before autoclaving,
the pH of the rooting medium was set at various pH values between 4.5 and 8.0. During autoclaving, the pH drifted in particular
in the alkaline region. Additional changes occurred during culture and the range set at 4.5–8.0 had shifted to 5.2–6.0 after
autoclaving and 3 weeks of culture. When 10 mM 2-(N-morpholino)ethanesulfonic acid (MES) had been added as buffering agent, the pH was stable when set at 5.0–6.5. Highest rooting
was achieved at pH ~5.3 with and without MES (pH measured after autoclaving). This maximum did not correlate with highest
auxin uptake. MES inhibited adventitious root formation during the initial phase of root formation when the meristemoids are
being formed (ca. 30% reduction at 10 mM) but was promotive during outgrowth of the meristemoids to roots (30% increase at
10 mM). Inhibition and promotion by MES were not related to its buffering action as they were observed at all pHs. 相似文献
11.
Role of Ethylene on de Novo Shoot Regeneration from Cotyledonary Explants of Brassica campestris ssp. pekinensis (Lour) Olsson in Vitro 总被引:5,自引:2,他引:3
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The promotive effect of AgNO3 and aminoethoxyvinylglycine (AVG) on in vitro shoot regeneration from cotyledons of Brassica campestris ssp. pekinensis in relation to endogenous 1-amino-cyclopropane-1-carboxylic acid (ACC) synthase, ACC, and ethylene production was investigated. AgNO3 enhanced ACC synthase activity and ACC accumulation, which reached a maximum after 3 to 7 days of culture. ACC accumulation was concomitant with increased emanation of ethylene which peaked after 14 days. In contrast, AVG was inhibitory to endogenous ACC synthase activity and reduced ACC and ethylene production. The promotive effect of AVG on shoot regeneration was reversed by 2-chloroethylphosphonic acid at 50 micromolar or higher concentrations, whereas explants grown on AgNO3 medium were less affected by 2-chloroethylphosphonic acid. The distinctive effect of AgNO3 and AVG on endogenous ACC synthase, ACC, and ethylene production and its possible mechanisms are discussed. 相似文献
12.
Yasuhiro Mori Fumihiko Miyahara Yuji Tsutsumi Ryuichiro Kondo 《Plant Growth Regulation》2011,63(3):271-278
Adventitious rooting is essential for cutting propagation of pine wilt-resistant Pinus thunbergii. To examine a variety of adventitious rooting potentials among donor plants, cuttings were taken from 31 seedlings within
a half-sib family. Rooting abilities of cuttings from each seedling ranged from 0 to 100%. When 11 ortets and 11 ramets (clonally
propagated from each ortet) were used as donor plants, there was a positive correlation between rooting abilities of cuttings
from ortets and ramets, suggesting that adventitious rooting is dependent on genetic factors in the donor plants. To promote
adventitious rooting of cuttings by hormonal treatment, we examined the effect of soaking time in Oxyberon (19.7 mM indole-3-butyric
acid (IBA) solution) on rooting. Ten minutes was the best soaking time for rooted cuttings to produce more adventitious roots
without impairing normal growth. When cuttings were soaked in Ethrel diluent (69.2 μM ethephon) for 24 h before soaking in
Oxyberon for 10 min, a significantly higher rooting ability was observed than those soaked in Oxyberon alone. Ethrel on its
own barely affected rooting ability. The positive effect of the combinational treatment was confirmed in a similar experiment
using authentic ethephon and IBA instead of Ethrel and Oxyberon. When cuttings were soaked in a mixture of ethephon and silver
thiosulfate (STS), an ethylene action inhibitor, before IBA-soaking, the effect was partially diminished compared with combinational
treatment without STS. These findings suggest that ethylene action caused by ethephon treatment promotes IBA-mediated adventitious
rooting of P. thunbergii cuttings. 相似文献
13.
Phuong T. Y. Dinh Marissa Roldan Susanna Leung Michael T. McManus 《Plant Growth Regulation》2012,66(2):179-190
The influence of P-supply on root system architecture (primary root length, number and total length of lateral roots) through
the effects of ethylene (ACC) and auxin [1-naphthylacetic acid (NAA)] has been examined in the legume white clover (Trifolium repens L.). Higher concentrations (1 and 10 μM) of ACC and NAA (100 nM) inhibited growth, while lower concentrations (100 nM ACC,
5 nM NAA) either had no effect or stimulated growth in P-sufficient (1 mM Pi) roots. In response to low (10 μM) P, a stimulation
of primary root growth, number of lateral roots and mean length of lateral roots was observed, while a super-stimulation of
these growth parameters occurred in response to subsequent 100 nM ACC treatment suggesting that the low P treatment increased
the sensitivity of the roots to ethylene. Examination of the primary roots of DR5p::GUS transformants suggests that this change in sensitivity induced by low P occurs through the promotion of auxin signalling/transport
to the root apex. These results are discussed in terms of the role of ethylene and the significance of changes in sensitivity
to the hormone in modulating root system architecture in response to low P-supply. 相似文献
14.
A protocol for plant regeneration from mesophyll and callus protoplasts of Robinia pseudoacacia L. was developed. For leaves from in vitro raised shoots, an enzyme combination of 2.0% cellulose and 0.3% macerozyme for
a digestion period of 20 h resulted in the best yield of protoplasts (9.45 × 105 protoplast/g fresh weight). Mesophyll-derived protoplasts started cell wall regeneration within 24 h of being embedded in
Nagata and Takebe (NT) medium supplemented with 5 μM NAA and 1 μM BAP followed by the first cell division on day three of
culture and micro-colony (32 cells) formation within day 7–10 in the same medium. However, using callus as the starting material,
a combination of 2.0% cellulose and 1.0% macerozyme for a digestion period of 24 h gave the highest protoplast yield (3.2 × 105 protoplast/g fresh weight). Cell wall regeneration in callus-derived protoplasts started within 24 h followed by the first
cell division on the day three (96 h) and the appearance of microcolonies of more than 32 cells by the end of first week (144 h)
of culture on solid WPM medium supplemented with 5 μM NAA and 1 μM BAP. Microcalli were visible to the naked eye after 45 days
on solid WPM medium. Proliferation of macro-calli was successfully accomplished on solid Murashige and Skoog (MS) medium with
5 μM NAA and 5 μM BAP. Both mesophyll and callus protoplast-derived calli produced shoots on MS medium with 0.5 μM NAA and
1 μM BAP within 25–30 days and multiplied on MS medium with 1.25 μM BAP. Excised microshoots were dipped in 1–2 ml of 2.0 μM
IBA for 24 h under dark aseptic conditions and transferred to double sterilized sand for rooting. The flasks containing sand
were inoculated with Rhizobium for in vitro nodulation. Forty-five plants transferred to pots in the glasshouse established well. 相似文献
15.
Paclobutrazol (PB), a triazole growth retardant and an inhibitor of gibberellin biosynthesis, reduced at 17 μM concentration
the adventitious root formation of bean primary leaf cuttings. Treatments with 5 μM ABA or 4 μM Ethrel, an ethylenereleasing
compound, restored the rooting of PB-treated cuttings. Ethylene production and the content of the precursor 1-aminocyclopropane-l-carboxylic
acid (ACC) were enhanced in root-forming tissues of PB-treated petioles 48 h after ABA application. The effect of ABA could
be abolished by 10 μM CoCl2, an inhibitor of ACC oxidase. Thus, ABA might stimulate rooting through its effect on ethylene release. 2 mM silver thiosulphate,
an inhibitor of ethylene action, decreased the rooting of PB-treated cuttings similarly to Co2+, but failed to negate the ABA effect. These data indicate that the effect of PB on rhizogenesis is not associated directly
with the inhibition of the biosynthesis of gibberellins
Acknowledgements: We are grateful to Gabriella Biró. This work was supported by the Hungarian National Science Research Foundation
(OTKA), Project No. 462. 相似文献
16.
Promotion by Ethylene of the Capability to Convert 1-Aminocyclopropane-1-carboxylic Acid to Ethylene in Preclimacteric Tomato and Cantaloupe Fruits 总被引:12,自引:6,他引:6
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The intact fruits of preclimacteric tomato (Lycopersicon esculentum Mill) or cantaloupe (Cucumis melo L.) produced very little ethylene and had low capability of converting 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. When these unripe tomato or cantaloupe fruits were treated with ethylene for 16 hours there was no increase in ACC content or in ethylene production rate, but the tissue's capability to convert ACC to ethylene increased markedly. Such an effect was also observed in fruits of tomato mutants rin and nor, which do not undergo ripening and the climacteric increase in ethylene production during the senescence. The development of this ethylene-forming capability induced by ethylene increased with increasing ethylene concentration (from 0.1 to 100 microliters per liter) and duration (1 to 24 hours); when ethylene was removed this capability remained high for sometime (more than 24 hours). Norbornadiene, a competitive inhibitor of ethylene action, effectively eliminated the promotive effect of ethylene in tomato fruit. These data indicate that the development of the capability to convert ACC to ethylene in preclimacteric tomato and cantaloupe fruits are sensitive to ethylene treatment and that when these fruits are exposed to exogenous ethylene, the increase in ethylene-forming enzyme precedes the increase in ACC synthase. 相似文献
17.
The possible interaction of the plant hormones auxin and ethylene and the role of 1-aminocyclopropane-1-carboxylate (ACC)
deaminase containing bacteria on ethylene production in canola (Brassica campestris) in the presence of inhibitory concentrations of growth regulators were investigated. The effects of auxin (indole-3-acetic
acid and 2,4-dichlorophenoxy acetic acid), auxin transport inhibitor 2-(p-chlorophenoxy)-2-methylpropionic acid, ethylene precursor 1-aminocyclopropane-1-carboxylate and ethylene synthesis inhibitor
l-α-(2-aminoethoxyvinyl)glycine hydrochloride on root elongation were concentration dependent. Exogenous addition of growth
regulators influences the enzyme activities of ethylene production and we have presented here evidences that support the hypothesis
that inhibitory effects of auxin on root elongation are independent of ethylene. Additionally, we have proved that inoculation
of ACC deaminase containing Methylobacterium
oryzae sequester ACC exuded from roots and hydrolyze them lowering the concentration of ACC in root exudates. However, the inhibitory
actions of exogenous additions of auxins could not be ameliorated by bacterial inoculation that reduces ethylene concentration
in canola seedlings. 相似文献
18.
Endogenous ethylene requirement for adventitious root induction and growth in tomato cotyledons and lavandin microcuttings in vitro 总被引:2,自引:0,他引:2
The role of ethylene in the formation of adventitious roots in vitro was studied in tomato (Lycopersicon esculentum Mill. cv. UC 105) cotyledons and lavandin (Lavandula officinalis Chaix × Lavandula latifolia microshoots. Both systems were able to form roots on hormone-free medium evolving low amounts of ethylene. The addition of 20–50 M indole-3-acetic acid (IAA) inhibited root formation in tomato cotyledons while increasing ethylene production. Naphthaleneacetic acid (NAA, 3 M) stimulated root number in lavandin explants and induced a transient rise in ethylene evolution. Enhanced ethylene levels via the endogenous precursors 1-aminocyclopropane-1-carboxylic acid (ACC, 25–50 M) drastically impaired root regeneration and growth in tomato. In lavandin, 10 M ACC stimulated ethylene production and significantly inhibited the rooting percentage and root growth. Conversely, ACC enhanced the root number in the presence of NAA only. Severe inhibition of rooting was also caused by ethylene reduction via biosynthetic inhibitors, aminoethoxyvinylglycine (AVG, 5–10 M) in tomato, and salicylic acid (SA, 100 M) in lavandin. A strict requirement of endogenous ethylene for adventitious root induction and growth is thus suggested.Abbreviations LS
Linsmaier and Skoog medium
- BA
N6-benzyladenine
- NAA
1-naphthaleneacetic acid
- IAA
Indole-3-acetic acid
- AVG
Aminoethoxyvinylglycine
- SA
Salicylic acid
- ACC
1-aminocyclopropane-1-carboxylic acid 相似文献
19.
Ethylene may be one of the many factors that play a role in rooting. However, in some studies ethylene promoted rooting, while in others it was inhibitory or had no effect. Using cotyledons of hazelnut ( Corylus avellana L. cv. Casina) observations were made of the effect of ethylene precursors on adventitious root formation. l-methionine (Met) or 1-aminocyclopropane-1-carboxylic acid (ACC) added to a standard indole-3-butyric acid (IBA)-kinetin-containing medium did not enhance rooting, while 2-chloroethylphosphonic acid (CEPA) did. The ethylene inhibitor, aminoethoxyvinylglycine (AVG), inhibited root formation, but its effect was reversed by ACC when cotyledonary segments were transferred to rhizogenic medium plus ACC at day 10. Ethylene production by cotyledons cultured on rhizogenic medium or rhizogenic medium plus CEPA was high at the beginning of rooting. Thus, the wound-induced ethylene is a key stimulatory factor in the formation of root primordia. The data support the hypothesis that ethylene plays a positive role in root formation. 相似文献
20.
Abdel Gabbar T. Babiker Tishu Cai Gebisa Ejeta Larry G. Butler William R. Woodson 《Physiologia plantarum》1994,91(3):529-536
Witchweed [ Striga asiatica (L.) Kuntze], an economically important parasitic weed on several poaceous crops, is difficult to control. In nature, germination and subsequent morphogenesis of Striga are cued to specific host-derived chemical signals. Seeds (approximately 2.4 mg) treated with thidiazuron (TDZ) or the auxins 2,4-dichlorophenoxy-acetic acid (2,4-D), 1-naphthalene acetic acid (NAA), or 2-(4-chloro- o -tolyloxy) propionic acid (MCPP) produced little ethylene (66-138 nl l−1 ). Combinations of TDZ with the auxins increased ethylene production by 4- to 18-fold. Ethylene production was strongly inhibited (86–92%) by aminoethoxyvinylglycine (AVG), inhibitor of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase. Ethylene evolved from seeds treated with TDZ in combination with 2,4-D increased after a lag period and was promoted by a pretreatment in 2,4-D. TDZ or any of the auxins, at the rates tested, effected negligible to low levels of germination (0 to 16%), whereas mixtures of TDZ with the above auxins stimulated 38 to 84% germination. Test solutions containing TDZ and indole-3-acetic acid (IAA) were, however, less effective. TDZ/auxin-induced germination was inhibited by AVG and the ethylene action inhibitor silver thiosulfate (STS). The inhibitory effect of the former was reversed by treatment with ACC. In vitro studies revealed negligible germination (< 1%) on control medium. Seeds germinating on media containing TDZ alone developed into seedlings with distinct shoots and rudimentary roots. Seeds germinating on media containing 2,4-D, irrespective of TDZ concentration, were induced to form calli. The results are consistent with a model in which both germination and subsequent morphogenesis in Striga are associated with exogenous and endogenous phytohormones. 相似文献