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1.
Influence of growth regulators on direct embryo formation from leaf explants of Phalaenopsis orchids
Leaf explants of two Phalaenopsis, P. amabilis and P. Nebula, were used to test the effects of auxins (2,4-D, IAA, IBA, NAA), cytokinins (2iP, BA, kinetin, TDZ, zeatin), GA3, ancymidol, polyamines (putrescine, spermine, spermidine), ACC, AgNO3 and CoCl2 on the amount of direct embryo formation on different leaf locations (the cut end, the adaxial side, the abaxial side and
the leaf tip). The results showed that there was a genotypic effect on direct embryo formation induced by cytokinins that
13.32 μM BA and 4.92 μM 2iP was the most effective in P. amabilis and P. Nebula, respectively. Besides, explant position highly affected embryogenic competence of leaf cells in both species that
the cut end showed highest embryogenic response, the adaxial side was the second, and then the abaxial side and the leaf tip.
Altogether, cytokinins tested were all effective in both species, and ACC at 20 μM had 35% of embryogenic response in P.
amabilis. However, auxins, GA3, ancymidol and polyamines were inhibitory in both species. 相似文献
2.
To study the effect of auxin on direct somatic embryogenesis from leaf cultures ofOncidium `Gower Ramsey', 1-cm-long explants have been cultured in vitro testing IAA, 2,4-, quercetin, TIBA and PCIB. On a modified MS medium devoid of plant growth regulators, leaf cells of three regions (leaf tips, adaxial sides and cut ends) formed somatic embryos. After 8 weeks in culture, the frequencies of embryo-forming explants were 55, 52.5 and 30 % on leaf tips, adaxial sides and cut ends, respectively, and the numbers of embryos per dish was 89.3. Except for TIBA, other growth regulators (IAA, 2,4-, quercetin, PCIB) and their combinations tested, all retarded direct embryo formation. In the presence of 0.1 and 0.5 M TIBA, leaf tip, adaxial sides and cuts end of explants gave almost the same embryogenic response as the control. However, 10 and 27.5 % of explants were induced to form embryos from abaxial sides, and these explants did not form embryos on cut ends. In addition, after 8weeks in culture, TIBA at 0.5M highly promoted the mean numbers of embryos per dish to 134.2. 相似文献
3.
To study the effect of auxin on direct somatic embryogenesis from leaf cultures ofOncidium `Gower Ramsey', 1-cm-long explants have been cultured in vitro testing IAA, 2,4-, quercetin, TIBA and PCIB. On a modified MS medium devoid of plant growth regulators, leaf cells of three regions (leaf tips, adaxial sides and cut ends) formed somatic embryos. After 8 weeks in culture, the frequencies of embryo-forming explants were 55, 52.5 and 30 % on leaf tips, adaxial sides and cut ends, respectively, and the numbers of embryos per dish was 89.3. Except for TIBA, other growth regulators (IAA, 2,4-, quercetin, PCIB) and their combinations tested, all retarded direct embryo formation. In the presence of 0.1 and 0.5 μM TIBA, leaf tip, adaxial sides and cuts end of explants gave almost the same embryogenic response as the control. However, 10 and 27.5 % of explants were induced to form embryos from abaxial sides, and these explants did not form embryos on cut ends. In addition, after 8?weeks in culture, TIBA at 0.5?μM highly promoted the mean numbers of embryos per dish to 134.2. 相似文献
4.
Summary A protocol for micropropagation of Virginia-type peanut plants, an ancient crop of the New World, is reported. This study
was conducted to explore the effect of silver nitrate (AgNO3), alone or in combination with growth regulators, on multiple shoot formation from shoot tip culture. Incorporation of AgNO3 into the medium, without growth regulators, induced regeneration of the explants (which did not develop at all in the AgNO3-free medium), and stimulated the emergence of axillary shoots. When AgNO3 was added in combination with cytokinins and α-naphthaleneacetic acid (NAA), maximum average shoot number per regenerating
explant was recorded (6.3) in Murashige and Skoog (MS) medium containing 33 μM 6-benzyladenine, 5.3 μM NAA, and 23.54 μM AgNO3. Moreover, AgNO3 showed a positive and marked effect on both shoot elongation and the reduction of callus proliferation from the basal ends
of shoot tips. Following a period of elongation, the shoots were rooted in hormone-free Ms medium, showing no residual effects
due to the long-term culture in AgNO3-containing media. Acclimatization was easily obtained after plantlets were transferred to pots under greenhouse conditions,
with 90% survival. 相似文献
5.
Muthu Thiruvengadam K. T. Rekha Chang-Hsien Yang Narayanasamypillai Jayabalan Ill-Min Chung 《Plant biotechnology reports》2010,4(4):321-328
An efficient protocol for in vitro organogenesis was achieved from callus-derived immature and mature leaf explants of Momordica charantia, a very important vegetable and medicinal plant. Calluses were induced from immature leaf explants excised from in vitro
(15-day-old seedlings) mature leaf explants of vivo plants (45 days old). The explants were grown on Murashige and Skoog (MS)
medium with Gamborg (B5) vitamins containing 30 g l−1 sucrose, 2.2 g l−1 Gelrite, and 7.7 μM naphthalene acetic acid (NAA) with 2.2 μM thidiazuron (TDZ). Regeneration of adventitious shoots from
callus (30–40 shoots per explant) was achieved on MS medium containing 5.5 μM TDZ, 2.2 μM NAA, and 3.3 μM silver nitrate (AgNO3). The shoots (1.0 cm length) were excised from callus and elongated in MS medium fortified with 3.5 μM gibberellic acid (GA3). The elongated shoots were rooted in MS medium supplemented with 4.0 μM indole 3-butyric acid (IBA). Rooted plants were
acclimatized in the greenhouse and subsequently established in soil with a survival rate of 90%. This protocol yielded an
average of 40 plants per leaf explant with a culture period of 98 days. 相似文献
6.
The effects of ethylene inhibitors (silver nitrate – AgNO3 and silver thiosulphate – Ag2S2O3 as inhibitors of ethylene activity, cobalt chloride – CoCl2 as inhibitor of ethylene biosynthesis) and ethylene stimulator (aminocyclopropane-1-carboxylic acid – ACC) were studied on
the growth of cauliflower (Brassica oleracea L.) seedlings cultured in closed vessels (60 cm3). The addition of ethylene inhibitors have significant stimulatory effects on the growth and development of seedlings and
the effects were greatest with 10 μM AgNO3, the fresh weight of leaves was 2.6×, and the leaf area 2.8× those of the control (no additives). The effects of various
methods of ventilation (humidity-induced convective through-flow ventilation, diffusive ventilation and sealed condition)
on the growth and physiology of in vitrocauliflower seedlings were also investigated. The seedlings were cultured either in the presence or absence of AgNO3 (inhibitors of ethylene activity) and ACC (a precursor). Ethylene and CO2 levels in the head-space of the culture vessels were monitored. The humidity-induced through-flow ventilation system has
shown to be effective for improving growth, leaf chlorophyll content and the rate of net photosynthesis and preventing symptoms
of hyperhydricity, such as leaf epinasty, and franginess, reduction of leaf area etc. In contrast, the results also indicated
that the sealing of culture vessels could have serious inhibitory effects on growth and development, induce hyperhydricity
and reduce leaf chlorophyll content.
In the light period, CO2 depletion occurred in the head-space of the sealed vessels (ca. 40 μl l-1), the CO2 concentration increased with increasing efficiency of the ventilation. No ethylene accumulation was noticed in the head-space
of the culture vessels when humidity-induced throughflow ventilation was applied; however, high ethylene accumulation occurred
in sealed vessels.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Four auxins (IAA, IBA, NAA and 2,4-D) and five cytokinins (2iP, zeatin,kinetin,BA and TDZ) were examined for their effects on direct somatic embryogenesis onleaf explantsof a sympodial orchid Oncidium 'Gower Ramsey.On a hormone-freebasal medium, the percentages of embryo formation were 40%, 20%,5% and0% on leaf tips, adaxial sides, wound surfaces and abaxial sides of theleaf explants, respectively, and the average number of embryos per explant was5.6. Embryo formation on leaf explants was retarded by all four auxins tested,but promoted by all the cytokinins. The percentages of embryo formation werereduced to 20%, 5–10%, 0% and 0%,respectively, in the same parts of leaf explants when supplemented with lowdogsages of IAA (0.3–3 mg/l) on the basal medium.Furthermore, embryo formation was totally inhibited by 3 mg/l NAA,0.3–3 mg/l IBA and 2,4-D. The sequence of embryo formationonvarious location of leaf explants was altered by 0.3–1 mg/l2iP and 3 mg/l zeatin, and embryo formation on adaxial sides>leaf tips>woundsurfaces>abaxial sides. The highest percentage of embryoformation on leaf tips, adaxial sides and wound surfaces of explants were75%, 50% and 20% when supplemented with 1mg/lTDZ, 1 mg/l 2iP and 0.3 mg/l kinetin, respectively.The highest average number of embryo per explant (10.7) was found on a basalmedium containing 1 mg/l TDZ. 相似文献
8.
The influence of light regime, explant position and orientation on direct embryo formation from leaf explants of two Phalaenopsis, P. amabilis and P. Nebula, were investigated to optimize the protocol for regenerating of this orchid. When explants were cultured in light,
direct embryogenesis was retarded in both species. Embryos showed whitish to pale green in color and larger size than those
cultured in darkness. Furthermore, light regime induced explant browning, embryo necrosis and eventually low plantlet conversion
rate. Sixty days of culture in darkness is the most suitable duration for direct embryo induction. Explant orientation also
significantly affected direct embryo formation, and explants placed adaxial-side-up on culture medium had higher embryogenic
response than abaxial-side-up orientation. In both species, the cut end had highest embryogenic competence than other parts
of the explant. Moreover, when the leaf explant was cut transversely into two segments, the leaf basal segment had higher
embryogenic competence than the leaf tip segment. 相似文献
9.
Radermachera sinica L. is an ornamental plant with demonstrated sensitivity to ethylene-induced leaf abscission. In this study, we examine the relationship between abscisic acid (ABA) and ethylene in initiating the abscission response. Treatment with 1 l L\s-1 of ethylene, 1 mM 1-aminocyclopropane-1-carboxylic acid (ACC) or 1 mM ABA resulted in complete defoliation of leaf explants. Application of 0.125 mM silver thiosulfate (STS) inhibited ethylene- and ACC-induced abscission but had no effect on explants treated with ABA. The ABA-induced abscission was unaffected by treatment with aminoethoxyvinylglycine (AVG) or aminooxyacetic acid (AOA). Treatment of explants with 1 mM cobalt chloride (CoCl2) or 2000 l L\s-1 of norbornadiene (NBD) completely inhibited abscission in explants treated with 1 l L\s-1 ethylene or 1 mM ACC but they were only marginally effective in blocking ABA-induced abscission despite the lower level of endogenous ethylene. ABA appeared to increase the sensitivity of explants to ethylene. However, the evidence suggests that ABA may also function independent of ethylene to induce leaf abscission in R. sinica.Abbreviations ABA
abscisic acid
- ACC
1-aminocyclopropane-1-carboxylic acid
- AOA
aminooxyacetic acid
- AVG
aminoethoxyvinylglycine
- CoCl2
cobalt chloride
- NBD
norbornadiene
- STS
silver thiosulfate 相似文献
10.
Jin Cui Jianjun Chen Richard J. Henny 《In vitro cellular & developmental biology. Plant》2009,45(1):34-43
Plant regeneration through direct somatic embryogenesis in Aeschynanthus radicans ‘Mona Lisa’ was achieved in this study. Globular somatic embryos were formed directly from cut edges of leaf explants and
cut ends or on the surface of stem explants 4 wk after culture on Murashige and Skoog (MS) medium supplemented with N-phenyl-N′-1, 2, 3-thiadiazol-5-ylurea (TDZ) with α-naphthalene acetic acid (NAA), TDZ with 2,4-dichlorophenoxyacetic acid (2,4-D),
or 6-benzylaminopurine (BA) or kintin (KN) with 2,4-D. MS medium containing 9.08 μM TDZ and 2.68 μM 2,4-D resulted in 71%
of stem explants producing somatic embryos. In contrast, 40% of leaf explants produced somatic embryos when induced in medium
containing 6.81 μM TDZ and 2.68 μM 2,4-D. Somatic embryos matured, and some germinated into small plants on the initial induction
medium. Up to 64% of stem explants cultured on medium supplemented with 9.08 μM TDZ + 2.68 μM 2,4-D, 36% of leaf explants
cultured on medium containing 6.81 μM TDZ and 2.68 μM 2,4-D had somatic embryo germination before or after transferring onto
MS medium containing 8.88 μM BA and 1.07 μM NAA. Shoots elongated better and roots developed well on MS medium without growth
regulators. Approximately 30–50 plantlets were regenerated from each stem or leaf explant. The regenerated plants grew vigorously
after transplanting to a soil-less substrate in a shaded greenhouse with more than a 98% survival rate. Three months after
their establishment in the shaded greenhouse, 500 plants regenerated from stem explants were morphologically evaluated, from
which five types of variants that had large, orbicular, elliptic, small, and lanceolate leaves were identified. Flow cytometry
analysis of the variants along with the parent showed that they all had one identical peak, indicating that the variant lines,
like the parent, were diploid. The mean nuclear DNA contents of the variant lines and their parent ranged from 4.90 to 4.99 pg
2C−1, which were not significantly different statistically. The results suggest that the regenerated plants have a stable ploidy
level, and the regeneration method established in this study can be used for rapid propagation of ploidy-stable Aeschynanthus radicans. 相似文献
11.
Two Phalaenopsis orchids, Phalaenopsis amabilis and Phalaenopsis ‘Nebula’, were used to test the effects of induction period (30, 45 and 60 days), subculture period (30, 45 and 60 days),
and explant length (1, 1.5 and 2 cm) on direct somatic embryogenesis from different regions (leaf tip, adaxial side, abaxial
side and cut end) of leaf explants from in vitro grown seedlings. The results showed that the cut end had a highest competence
to form embryos than the other regions of the leaf explants from both orchids. In addition, the suitable culture conditions
were 60 days for induction period in darkness, 45 days for subculture period in light and 1 cm for explant length. Besides,
the combinations of N6-benzyladenine (BA) and naphthaleneacetic acid were tested on their effects on plantlet conversion and further development
of leaf-derived embryo. It was found that 0.5 mg/l of BA showed the highest response on plantlet conversion rate and the lowest
browning rate of explants. In this communication, the embryo structures and development were proved by scanning electron microscopy. 相似文献
12.
Summary The promotive effect of ethylene inhibitors (Els), i.e. AgNO3 and aminoethoxyvinylglycine (AVG) on de novo shoot regeneration from cultured cotyledonary explants of Brassica campestris ssp. pekinensis cv. Shantung in relation to polyamines (PAs) was investigated. The endogenous levels of free putrescine and spermidine in the explant decreased sharply after 1–3 days of culture, whereas endogenous spermine increased, irrespective of the absence or presence of Els. AgNO3 at 30 M did not affect endogenous PAs during two weeks of culture. In contrast, explants grown on medium containing 5 M AVG produced higher levels of free putrescine and spermine which increased rapidly after three days and reached a peak at 10 days. An exogenous application of 5 mM putrescine also resulted in a similar surge of endogenous free spermine of the explant. More strikingly, shoot regeneration from explants grown in the presence of 1–20 mM putrescine, 0.1–2.5 mM spermidine, or 0.1–1 mM spermine was enhanced after three weeks of culture. However, exogenous PAs generally did not affect ethylene production, and endogenous levels of 1-aminocyclopropane-1-carboxylate (ACC) synthase activity and ACC of the explant. This study shows the PA requirement for shoot regeneration from cotyledons of B. campestris ssp. pekinensis in vitro, and also indicates that the promotive effect of PAs on regeneration may not be due to an inhibition of ethylene biosynthesis.Abbreviations PAs
polyamines
- AVG
aminoethoxyvinylglycine
- SAM
S-adenosylmethionine
- ACC
1-aminocyclopropane-1-carboxylate
- Els
ethylene inhibitors 相似文献
13.
Amanpreet Kaur M. Sudhakara Reddy Anil Kumar 《Plant Cell, Tissue and Organ Culture》2018,134(3):457-466
Direct somatic embryo induction was achieved from leaf and internodal explants of Solanum tuberosum (L.) cultivar ‘Kufri Chipsona 2’ on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium containing 10.0 µM silver nitrate (MS1 medium) supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D; 2.5 µM) and 6-benzyladenine (BA; 1.0 µΜ). It was observed that in absence of AgNO3, friable callus was induced from cut ends of the explants, which does not develop into any kind of organised structure; thus highlighting the requirement of AgNO3 for somatic embryogenesis in potato. Furthermore, the effect of medium strength, sucrose concentration and heat shock treatment on somatic embryogenic potential of explants was also investigated. When the strength of basal medium was reduced to half, the frequency of internodal segments differentiating somatic embryos was almost double in comparison to full strength MS medium. Sucrose concentration and heat shock treatment were found to have interactive effect on somatic embryo induction. Explants subcultured on medium containing 174 mM sucrose and subjected to heat shock (1 h; 50 °C) showed maximum somatic embryo differentiation. Although, the percent explants differentiating somatic embryos decreased sharply with increase in sucrose concentration (>?174 mM), yet the number of somatic embryos differentiated per explant were found to increase with further increase in sucrose concentration. Histological observations revealed that somatic embryos directly developed from epidermis of leaf explant and cut ends of internodal segments progressed from globular to cotyledonary stage after passing through intermediate embryogenic stages (heart shaped and torpedo shaped). Conversion of somatic embryos into plantlets (92%) was achieved on MS1 medium supplemented with BA (10.0 µM) and gibberellic acid (15.0 µM) and all regenerated plants were found to be phenotypically alike. 相似文献
14.
P. G. Golegaonkar A. S. Kantharajah 《In vitro cellular & developmental biology. Plant》2006,42(4):341-344
Summary
In vitro plantlet regeneration was obtained from cultured cotyledon and young leaf explants of five Indian chile pepper cultivars
(Capsicum annuum L. evs. Gujarat-1, Gujarat-2, Guntur-4, Selection-49, and Jwala). Adventitious shoot buds (ASB) were regenerated directly
from cotyledon and young leaf explants in all the five cultivars on media containing benzyladenine (BA) alone or in combination
with 1-naphthaleneacetic acid (NAA). Regeneration frequency was highly influenced by cultivar explant type, media combination
and their interactions, except the interaction between cultivar and explant, for number of ASB per explant. Percent contribution
of individual source suggested that selection of explant type followed by medium combination and cultivars was essential for
obtaining high-frequency ASB induction. Across different cultivars the young leaf explant was found to be the most responsive
explant, while Murashige and Skoog (MS) medium containing BA alone (17.8, 26.6, and 35.5 μM) was found to be the best medium for the production of maximum number of ASB. Between the two explants, shoot elongation
was observed with ASB obtained from young leaf explants on MS medium containing BA (2.2 and 4.4 μM) and gibberellie acid (GA3) (1.4, 2.9, 4.3 and 5.8 μM). The MS medium fortified with 4.4 μM BA+2.9μM GA3 was optimum for shoot elongation. Elongated shoots were rooted on liquid MS medium supplemented with 2.9 μM indole-3-acetic acid (IAA) and successfully established ex vitro. 相似文献
15.
Summary Leaf segments of the orchid sp. Phalaenopsis ‘Little Steve’ were used as explants testing the effects of 2,4-dichlorophenoxyacetic acid (2,4-D; 0.45, 2.26, 4.52 μM), 6-furfurylaminopurine (kinetin; 2.32, 4.65, 13.95 μM), N6-benzyladenine (BA; 2.22, 4.44, 13.32 μM), and 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea (TDZ; 2.27, 4.54, 13.62μM) on the induction of direct somatic embryogenesis. After 20–30 d of culture in darkness, clusters of somatic embryos formed
from leaf surfaces and wounded regions of explants on half-strength Murashige and Skoog medium supplemented with BA and TDZ.
However, kinetin had no response on direct embryo induction. In addition, 2,4-D highly retarded the frequency of embryogenesis
that was induced by TDZ. Generally, adaxial surfaces near wounded regions had the highest embryogenic competency compared
to other regions of explants. Histological sections revealed that somatic embryos mostly arose from epidermal cell layers
of the explants. Secondary embryogenesis occurred at basal parts of embryos, and originated from outer cell layers. Following
transfer of regenerated embryos onto growth regulator-free medium for 3.5–4 mo., plantlets with three to four leaves and several
roots were obtained. This protocol provides a simple way to regenerate plants through direct somatic embryogenesis, and is
suitable for further studies on embryo development and genetic transformation of Phalaenopsis. 相似文献
16.
Ethylene inhibitors enhance in vitro root formation on faba bean shoots regenerated on medium containing thidiazuron 总被引:8,自引:0,他引:8
The possible involvement of ethylene in in vitrorooting of faba bean (Vicia faba L.) shootsregenerated on medium containing thidiazuron wasinvestigated. The effects of the ethylene precursor1-aminocyclopropane-1-carboxylic acid (ACC) and threeethylene inhibitors, silver nitrate (AgNO3),acetyl salicylic acid (ASA) and cobalt chloride(CoCl2) on root formation were tested in vitrousing TDZ-induced shoots of faba bean accession 760.ACC inhibited root formation. In contrast, ethyleneinhibitors promoted root formation, AgNO3 at theappropriate concentrations enhanced root emergence andincreased root number per shoot, root growth rate, androot length. Both CoCl2 and ASA at theappropriate concentrations increased rootingefficiency. These promotive effects may result from areduction in ethylene concentration or inhibition ofethylene action. The results offer a new approach toimprove the rooting efficiency of TDZ-induced shootsof faba bean and possibly of other plant species. 相似文献
17.
Dong-Ho Shin Jin Sook Kim In Jeong Kim Jaemo Yang Soo Kyung Oh Gab Chae Chung Kyung-Hwan Han 《In vitro cellular & developmental biology. Plant》2000,36(4):273-278
Summary We describe a protocol, and several experiments that helped lead to its development, for sunflower regeneration. Important
factors for sunflower regeneration were explant age, cytokinin type and concentration, basal medium, and explant source. We
could not induce shoot regeneration from the explants derived from mature tissues including leaf, petiole, and stem. However,
use of juvenile explants such as embryo meristem and primordial leaf tissues allowed routine regeneration of 17 different
sunflower genotypes. High frequency of shoot regeneration was achieved with these explants taken from seedlings up to 5 d
after germination. Explant age was less critical for embryo meristem explants than for primordial leaf tissues. Of the four
basal media tested, MS and B5 media produced higher shoot-regeneration frequencies than did Anderson and woody plant media.
The highest shoot-regeneration frequency was obtained with MS medium supplemented with 2 μM BA and without auxin. Addition of 1 μM naphthalene-acetic acid to the medium significantly reduced both the percentage of explants producing shoots and average
number of shoots per explant. Regenerated shoots were grown to maturity in a greenhouse. 相似文献
18.
Yanhong Cui Lu Hou Xiang Li Feiyi Huang Xiaoming Pang Yingyue Li 《Plant Cell, Tissue and Organ Culture》2017,129(1):175-180
The genetic manipulation of Capsicum has been unsuccessful, and a large bottleneck to transferring the desired genes is due to the difficulty in regenerating whole plants through tissue culture because of its highly recalcitrant and high genotype specificity. This study aimed to investigate and establish rapid shoot regeneration from the proximal ends of the leaves of Capsicum frutescens KT-OC and BOX-RUB varieties. A maximum of 8–10 shoot buds were obtained from the margins of the proximal portion of a cotyledonary leaf explant of C. frutescens variety KT-OC on medium I containing 44.44 µM 6-benzylaminopurine (BA), 5.71 µM indole-3-acetic acid (IAA), 10 µM silver nitrate (AgNO3) and 1.98 mg L?1 2-(N-morpholine) ethane sulphonic acid within 4 weeks of incubation, of which 60% of explants responded in terms of shoot buds. Petiole explants (40%) cultured on the same medium produced 2–4 shoots per explant from the distal portion. The cut portions of the cotyledonary leaf proximal portions responded well to shoot bud formation in the presence of 22.20 µM BA and 14.68 µM phenyl acetic acid (PAA), wherein 100% of explants responded in terms of shoot bud formation, with an average of 10?±?1.7 and 8?±?1.9 shoot buds per explant in KT-OC and BOX-RUB varieties, respectively. The differentiated shoots grew well and proliferated in the presence of 14.68 µM PAA?+?22.20 µM BA and 10 µM AgNO3. Shoot elongation was obtained in presence of 1.44 µM gibberellic acid (GA3) and 10 µM AgNO3. These shoots were rooted on plant growth regulator-free half-strength MS medium and upon hardening; field survival rate was 70%. This reproducible regeneration method for C. frutescens, especially the Indian high pungent variety, from proximal portion of cotyledonary leaf and petiole explants, can be used for biotechnological improvement. 相似文献
19.
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
20.
Luping Qu Jianjn Chen Richard J. Henny Yingfeng Huang Russell D. Caldwell Cynthia A. Robinson 《In vitro cellular & developmental biology. Plant》2002,38(3):268-271
Summary Regeneration of adventitious shoots of pothos (Epipremnum aureum Linden and Andre) ‘Jade’ was obtained using leaf and petiole explants preprated from shoot tips of 3-yr-old greenhouse-grown
plants. Explants were cultured on Murashige and Skoog (MS) basal medium supplemented with thidiazuron (TDZ), 6-(4-hydroxy-3-methy-trans-2-butenyl-amino)purine
(zeatin) or N-isopentenylaminopurine (2iP) individually with α-naphthaleneacetic acid (NAA) in 18 combinations. Callus was initiated from
cut surface and along the midrib or major vein of leaf sections. Shoot regeneration from leaf and petoole explants occurred
in 30d on medium containing 1, 5 or 10μM TDZ with 0.5 or 1.0μM NAA except petioles on medium with 10 μM TDZ and 1.0 μM NAA where regeneration failed. More time (50d) was needed for shoot regeneration when explants were cultured on medium containing
either 2iP or zeatin with NAA. Regeneration frequencies were up to 20% and 50% for leaf and petiole explants, respectively.
Shoot numbers per responding explant attained 30 for leaf and petiole explants on medium containing TDZ but only one to four
on medium containing either 2iP or zeatin. These results indicate that TDZ is a more effective cytokinin for in vitro regeneration of pothos than either zeatin or 2iP.. Shoots elongated readily and rooted well on MS basal medium, without plant
growth regulators. Plantlets acclimatized rapidly and grew vigorously in the greenhouse after transfer to pots containing
a commerecial potting medium. 相似文献