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1.
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
2.
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
3.
Summary Four auxins (2,4-dichlorophenoxyacetic acid [2,4-D], indole-3-acetic acid [IAA], indole-3-butyric acid [IBA], and naphthaleneacetic
acid [NAA]), and five cytokinins (N
6-[2-isopentenyl]-adenine [2iP], N
6-benzyladenine [BA], 6-furfurylaminopurine [kinetin], 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea [TDZ], and 6-[4-hydroxy-3-methylbut-2-enylamino]purine
[zeatin]) were examined for their effects on direct embryo induction from leaf explants of Dendrobium cv. Chiengmai Pink cultured on 1/2 Murashige and Skoog (MS) medium. Whether in light or darkness, explants easily became
necrotic and no embryos were obtained on growth regulator-free or auxin-containing media after 60 d of culture. By contrast,
five cytokinins tested induced direct embryo formation from leaf explants, and explants cultured in light had a higher embryogenic
response compared with those cultured in darkness. The best condition for direct embryo induction was at 18.16 μM TDZ cultured in light for 60 d, where 33% of explants formed a mean number of 33.6 embryos per explant. During subculture
on growth regulator-free 1/2 MS medium, embryos gradually developed into plantlets. Secondary embryogenesis was occasionally
found on sheath leaves of embryos. Regenerated plantlets were successfully transplanted and grown in a greenhouse environment. 相似文献
4.
Ai Hua Chen Jing Li Yang Yu Da Niu Chuan Ping Yang Gui Feng Liu Chang Yeon Yu Cheng Hao Li 《Plant Cell, Tissue and Organ Culture》2010,102(3):357-364
We developed a new protocol for highly efficient somatic embryogenesis and plantlet conversion of Schisandra chinensis. Friable embryogenic callus was induced from cotyledonary leaves and hypocotyls of germinated zygotic embryos on Murashige
and Skoog (MS) agar medium containing 2,4-dichlorophenoxyacetic acid (2,4-D). Preculture of zygotic embryos on 2,4-D-containing
medium increased embryogenic callus induction efficiency. The highest embryogenic callus induction frequency of 56.7% was
obtained from shoot apical meristem-containing hypocotyl explants from 1-week-old germinated embryos on MS medium containing
4.0 mg l−1 2,4-D. Embryogenic callus proliferation, somatic embryo (SE) formation, and subsequent plantlet conversion occurred under
optimal culture conditions. The effects of MS medium strength, sucrose, gibberellic acid (GA3), and 6-benzyladenine (BA) on SE formation and plantlet conversion were evaluated. Low MS medium strength (1/4 to 1/2) was
necessary for SE formation, and the optimal sucrose concentration was 2.0%. Supplementing medium with GA3 negatively impacted SE formation and subsequent development. BA significantly increased the number of SEs and the plantlet
conversion capacity. One-third-strength MS medium with 1.0% sucrose and 0.5 mg l−1 BA produced the highest number of SEs (309 embryos from 9 mg embryogenic callus) and the highest frequency of plantlet conversion
from germinated SEs (52.6%). When transplanted to soil, 90% of the regenerated plants developed into normal plants. 相似文献
5.
The goal of this research was to develop a rapid and efficient system for regenerating shoots from leaf explants of European birch, Betula pendula Roth. Single-node stem explants were established in culture, and microshoots were subcultured every 4 weeks through 12 subcultures. Leaves from glasshouse plants or subcultured shoots were excised from stems, cut into approximately 35-mm2 pieces, and placed on Woody Plant Medium (WPM) containing different combinations of naphthaleneacetic acid (NAA) (0, 3, 6 or 9 M) and benzyladenine (BA) (0, 7.5, 15 or 22.5 M) in a 4×4 factorial design. The percentage of leaf pieces forming shoots and the number of shoots regenerated per explant were recorded after 4 weeks. Only media containing BA without NAA stimulated shoot formation on leaf explants. Fifteen micromolar BA induced the most shoots to form on leaf explants compared to 30, 45 or 60 M of this cytokinin. In addition, shoot regeneration was enhanced up to four-fold between the first and eleventh subculture. Over 90% of the leaf explants regenerated shoots with an average of 18 buds formed per explant for the eleventh subculture. Almost twice as many explants formed shoots if their adaxial side was in contact with the medium rather than oriented away from it. The ability to regenerate shoots from leaves varied among plants, regardless of stock plant age. This reliable shoot regeneration system can be used for rapid shoot proliferation and potentially for genetic engineering of European birch. 相似文献
6.
Seabuckthorn (Hippophae rhamnoides) is a multipurpose small tree with unique berries of high nutritional and pharmaceutical values. A clonally propagated plant
originating from a 20-year-old tree of H. r. rhamnoides × mongolica hybrid cultivar Julia and seedling offspring of this cultivar were investigated regarding induction of shoot organogenesis
in leaf explants and in roots of intact seedlings, and induction of direct somatic embryogenesis in explants from shoot tissue.
The highest percentage of leaf explants showing shoot organogenesis was achieved (juvenile explants, 65%; adult explants,
75%) when incubated in Murashige and Skoog (MS) medium supplemented with either 4.5 μM of the phenylurea cytokinin thidiazuron
(TDZ) or 2.25 μM TDZ plus 2.2 μM 6-benzyladenine (BA), for juvenile and adult explants, respectively, both supplemented with
0.53 μM α-naphthaleneacetic acid (NAA). Juvenile explants developed on average 18 shoots per explant in the MS medium supplemented
with 4.5 μM TDZ, a four fold increase over those incubated on the medium supplemented with 2.25 μM TDZ and 2.2 μM BA. Adult
leaf explants grown on medium containing 2.25 μM TDZ and 2.2 μM BA medium produced 12 shoots per explant, while those grown
on medium containing 4.5 μM TDZ produced 5 shoots per explant. Shoot organogenesis was observed in roots of intact seedlings
pre-cultured on plain medium lacking nutrients (PM) or woody plant medium (WPM) salts and then grown on WPM salts supplemented
with 4.4 μM BA, 0.29 μM gibberrelic acid (GA3), and 57.0 μM indoleacetic acid (IAA). The number of shoots formed on each seedling
root system was ten fold higher when the pre-culture was in WPM medium indicating a promoting effect of mineral nutrients
in the pre-culture medium. Somatic embryogenesis was induced in both juvenile and adult leaf explants in 65 and 78% of the
explants, respectively, in MS-based medium supplemented with 2.0 μM N-(2-Chloro-4-pyridyl)-N
1-phenylurea (CPPU), 0.53 μM NAA and varying concentrations of BA. There was an interaction effect between MS salt strength
and BA concentration. The most effective medium for inducing somatic embryogenesis in juvenile explants contained half strength
MS salts and 2.2 μM BA and full strength MS salts and 13.2 μM BA for adult explants. 相似文献
7.
F. D. Espasandin M. M. Collavino C. V. Luna R. C. Paz J. R. Tarragó O. A. Ruiz L. A. Mroginski P. A. Sansberro 《Plant Cell, Tissue and Organ Culture》2010,102(2):181-189
A protocol for the production of transgenic plants was developed for Lotus tenuis via Agrobacterium-mediated transformation of leaf segments. The explants were co-cultivated (for 3 days) with an A. tumefaciens strain harbouring either the binary vector pBi RD29A:oat arginine decarboxylase (ADC) or pBi RD29A:glucuronidase (GUS), which
carries the neomycin phosphotransferase II (nptII) gene in the T-DNA region. Following co-cultivation, the explants were cultured in Murashige and Skoog medium supplemented
with naphthalenacetic acid (NAA) and benzyladenine (BA) and containing kanamycin (30 μg ml−1) and cefotaxime (400 μg ml−1) for 45 days. The explants were subcultured several times (at 2-week intervals) to maintain the selection pressure during
the entire period. About 40% of the explants inoculated with the pBiRD29:ADC strain produced eight to ten adventitious shoots
per responsive explant through a direct system of regeneration, whereas 69% of the explants inoculated with the pBi RD29A:GUS
strain produced 13–15 adventitious shoots per responsive explant. The selected transgenic lines were identified by PCR and
Southern blot analysis. Three ADC transgenic lines were obtained from 30 infected explants, whereas 29 GUS transgenic lines
were obtained from 160 explants, corresponding to a transformation efficiency of 10 and 18.1%, respectively. More than 90%
of the in vitro plantlets were successfully transferred to the soil. The increase in the activity of arginine decarboxylase
from stressed ADC- Lt19 lines was accompanied by a significant rise in the putrescine level. The GUS transgenic line driven by the RD29A promoter
showed strong signals of osmotic stress in the leaves and stem tissues. All of the transgenic plants obtained exhibited the
same phenotype as the untransformed controls under non-stress conditions, and the stability of the gene introduced into the
cloned materials was established. 相似文献
8.
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
9.
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
10.
The induction of somatic embryogenesis from shoot apices and leaf explants of shoot cultures derived from 6- to 7-year-old
white oak (Quercus alba L.) trees is reported in this study. Embryogenic response was obtained in two out of the three genotypes evaluated with embryo
induction frequencies up to 50.7% for WOQ-1 and 3.4% for WOQ-5 genotypes. The embryogenic explants formed translucent nodular
structures and cotyledonary-stage somatic embryos, which developed from callus tissue, indicating an indirect embryogenesis
process. An efficient procedure was developed for WOQ-1 material on the basis of the most appropriate leaf developmental stage.
Growing leaves excised from two nodes below the shoot apex showed the highest embryogenic induction index. These leaves contain
cells in an undifferentiated state, as shown by the presence of precursor cells of stomata, absence of intercellular spaces
and low starch content in the mesophyll cells. Nodular structures and/or somatic embryos began to arise 7–8 weeks after culture
initiation, although most emerged after 9–12 weeks in culture. The sequence of application of media for somatic embryo induction
was optimized with a two-step procedure consisting of culturing the explants in medium supplemented with 21.48 μM NAA and
2.22 μM BA for 8 weeks and transfer of explants into plant growth regulator-free medium for another 12 weeks. Clonal embryogenic
lines were established and maintained by secondary embryogenesis. Embryo germination (30%) and plantlet conversion (16.6%)
were achieved after cold storage for 2 months. 相似文献
11.
Xingyu Yang Jinfeng Lü Jaime A. Teixeira da Silva Guohua Ma 《Plant Cell, Tissue and Organ Culture》2012,109(2):213-221
Primulina tabacum is a rare and endangered species that is endemic to China. Establishing an efficient regeneration system is necessary for
its conservation and reintroduction. In this study, when leaf explants collected from plants grown in four ecotypes in China
are incubated on Murashige and Skoog (MS) medium containing 5.0 μM thidiazuron (TDZ) for 30 days, then transferred to medium
containing 5.0 μM 6-benzyladenine (BA), adventitious shoots are then observed. Conversely, when leaf explants are incubated
on medium containing 5.0 μM BA for 30 days, then transferred to medium containing 5.0 μM TDZ, somatic embryogenesis is induced.
This indicates that somatic embryogenesis and shoot organogenesis could be switched simply by changing the order of two cytokinins
supplemented in the culture medium. Histological investigation has revealed that embryogenic cells are induced within 30 days
following incubation of explants in medium containing TDZ. Only if embryogenic cells were induced, TDZ could enhance somatic
embryogenesis and BA could stimulate shoot organogenesis. When comparing explants from different ecotypes, leaf explants
from Zixiadong in Hunan Province could induce low numbers (1–2) of either somatic embryos or adventitious shoots on medium
containing either 5.0 μM TDZ or 5.0 μM BA, respectively. Whereas, leaf explants from plants collected from the other three
ecological habitats could induce 50–70 somatic embryos/adventitious shoots per explant. Moreover, somatic embryos could induce
secondary somatic embryogenesis and adventitious shoots on different media. All regenerated shoots developed adventitious
roots when these are transferred to rooting medium, and over 95% of plantlets have survived following acclimatization and
transfer to a potting mixture (1:1, sand:vermiculite). 相似文献
12.
W.-L. Teng 《Plant cell reports》1999,18(5):363-368
In vitro culture of Venus fly-trap (Dionaea muscipula) was initiated using flower stalk explants. Activated charcoal was required for bud initiation, but omitted in the subculture
of regenerated plantlets. Regenerated plants were subsequently used as explant source for investigations concerning effects
of source of tissue, etiolation, orientation and illumination of leaf explants on plant regeneration. Etiolation of source
plantlets increased the rate of regeneration from explants and decreased explant failure. Generally, adventitious buds developed
at the adaxial side and proximal end of an explant. However, when explants were incubated in the dark, 20–30% of bud initiation
occurred at the distal end. The site of shoot regeneration on a leaf explant was affected by both illumination and orientation
of explants. Placing an explant adaxial side up resulted in the highest rate of regeneration. The most effective condition
for plantlet regeneration was found with etiolated petioles incubated with the adaxial side facing the light.
Received: 18 March 1998 / Revision received: 12 August 1998 / Accepted: 7 September 1998 相似文献
13.
Charlene Chang Ben A. Moll Kathleen B. Evenson Mark J. Guiltinan 《Plant Cell, Tissue and Organ Culture》1996,45(1):61-66
In vitro plantlet regeneration systems for the seed geranium (Pelargonium x hortorum Bailey) using cotyledon, hypocotyl and root explants were optimized by studying the influence of seedling age, growth regulators and excision orientation on organogenesis. Indole-3-acetic acid combined with zeatin yielded the highest rate of shoot production on cotyledon explants (0.2–2 shoots per explant). More shoots were produced on explants cut from the most basal region of cotyledons from 2 to 4-day-old seedlings than from older seedlings or more distal cut sites. Hypocotyl explants produced the highest number of shoots, up to 40 shoots per explant, on indole-3-acetic acid (2.8–5.6 mM) + zeatin (4.6 mM) or thidiazuron (4.5 mM). Maximum shoot formation (0.3–1.4 shoots per explant) on root explants occurred when they were cultured on medium containing zeatin. Regenerated shoots rooted best on a basal medium containing no growth regulators. There were substantial differences among cultivars in shoot formation from each of the explant systems.Abbreviations BA
6-benzylaminopurine
- 2,4-d
2,4-dichlorophenoxyacetic acid
- IAA
indole-3-acetic acid
- NAA
naphthaleneacetic acid
- TDZ
thidiazuron 相似文献
14.
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
15.
A. M. Vieitez E. Corredoira A. Ballester F. Muñoz J. Durán M. Ibarra 《Plant Cell, Tissue and Organ Culture》2009,98(2):135-145
North American oak species, with their characteristic strong episodic seasonal shoot growth, are highly problematic for clonal
micropropagation, resulting in the inability to achieve a stabilized shoot multiplication stage. The potential for initiating
and proliferating shoot cultures derived from Quercus alba, Q. bicolor and Q. rubra explants was investigated, and a micropropagation method for these species was developed. Branch segments from 6 to 7-year-old
trees were forced-flushed and the forced shoots were used as source of explants for culture initiation. A consistent shoot
multiplication stage was achieved, in 13 of the 15 genotypes established in vitro, although marked differences occurred in
explants from different genotypes/species. The control of efficient shoot multiplication involved the culture of decapitated
shoots in a stressful horizontal position on cytokinin-containing medium with a sequence of transfers within a 6-week subculture
cycle, which was beneficial to overcoming the episodic character of shoot growth. During each subculture cycle, the horizontally
placed explants were cultured on media containing 0.2 mg l−1 benzyladenine (BA) for 2 weeks with two successive transfers (2 weeks each) to fresh medium with 0.1 mg l−1 BA, giving a 6-week subculture cycle. The general appearance and vigor of Q. alba and Q. bicolor shoot cultures were improved by the inclusion of both 0.1 mg l−1 BA and 0.5 mg l−1 zeatin in the medium used for the second transfer within the 6-week subculture cycle. Addition of AgNO3 (3 mg l−1) to the shoot proliferation medium of Q. rubra had a significant positive effect on shoot development pattern by reducing deleterious symptoms, including shoot tip necrosis
and early senescence of leaves. The three species showed acceptable in vitro rooting rates by culturing microcuttings in medium
containing 25 mg l−1 indolebutyric acid for 48 h with subsequent transfer to auxin-free medium supplemented with 0.4% activated charcoal. Although
an initial 5-day dark period generally improved the rooting response, it was detrimental to the quality of regenerated plantlets.
However, activated charcoal stimulated not only the rooting frequencies, but it also enhanced plant quality, as evidenced
by root, shoot and leaf growth. 相似文献
16.
Raya Liberman Liat Shahar Ada Nissim-Levi Dalia Evenor Moshe Reuveni Michal Oren-Shamir 《Plant Cell, Tissue and Organ Culture》2010,100(3):345-348
A protocol for plantlet regeneration through shoot formation was developed for the neotropical shrub Brunfelsia calycina. This shrub is unique in its change in flower color from dark purple to white. Explants from young and mature leaves were
incubated on MS medium (pH 5.7, 30 g/l sucrose, 7.5 g/l agar) with various combinations of Indole-3-acetic acid (IAA) and
6-Benzyladenine (BA) under a 16 h photoperiod at a constant temperature of 25°C. Shoot emergence was best at 4.44 μM BA and
2.85 μM IAA for young leaf explants, and at 8.88 μM BA, 2.85 μM IAA for mature leaf explants. When shoots were transferred
to MS medium supplemented with 1.23–2.46 μM indole butrytic acid (IBA), they developed roots. 相似文献
17.
A rapid and reliable micropropagation method was established for Spathoglottis plicata. Nodal and leaf explants dissected from 8-month-old pot-grown seedlings were cultured on charcoal-amended Murashige and Skoog
medium supplemented with 16 combinations of α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BA) at concentrations
of 0.54–10.74 μm. Regeneration of protocorm-like bodies (PLBs) and subsequent plantlet development were observed from 98.5% of the nodal explants.
Only 6.5% of leaf explants and occasionally some root segments (dissected from regenerated plantlets) were able to produce
PLBs and then plantlets. The optimum plant growth regulator (PGR) combination for maximal PLB regeneration was 5.37 μm NAA and 0.44 μm BA. The best combination of PGR for plantlet development was 2.69–10.74 μm NAA and 8.88 μm BA. The NAA to BA ratios for maximal PLB induction and plantlet development were 12.2 and 0.3–1.2, respectively. Regenerated
PLBs and plantlets, when cut into pieces of less than 1 mm and subcultured onto the above media, regenerated new PLBs and
plantlets in another 3 months.
Received: 20 February 1997 / Revision received: 27 May 1997 / Accepted: 16 June 1997 相似文献
18.
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
19.
Bimal Kumar Ghimire Chang Yeon Yu Ill-Min Chung 《Plant Cell, Tissue and Organ Culture》2012,108(3):455-464
A simple and efficient procedure was developed for in vitro propagation of Solanum aculeatissimum Jacq. using leaf and petiole explants cultured on Murashige and Skoog (MS) medium supplemented with α-naphthalene acetic
acid (NAA) and 6-benzyladenine (BA). Effects of various plant growth regulators, explant types, carbohydrates, and basal salts
on induction of adventitious shoots were also studied. Leaf explants appeared to have better regeneration capacity than petiole
explants in the tested media. The highest regeneration frequency (79.33 ± 3.60%) and shoot number (11.33 ± 2.21 shoots per
explant) were obtained in leaf explants in MS medium containing 3% sucrose and 0.8% agar, supplemented with 0.1 mg/l NAA and
2.0 mg/l BA, whereas petiole explants were more responsive to 0.1 mg/l NAA and 1.0 mg/l thiadiazuron. Developed shoots rooted
best on MS medium with 1.0 mg/l indole acetic acid (IAA), producing 18.33 ± 2.51 roots per shoot. Histological investigation
showed that the shoot buds originated mainly from epidermal cells of wounded tissues, without callus formation. The regenerated
plantlets were successfully acclimatized in a greenhouse, where over 90% developed into morphologically normal and fertile
plants. Results of flow cytometry analysis on S. aculeatissimum indicated no variation in the ploidy levels of plants regenerated via direct shoot formation and showed almost the same phenotype
as that of mother plants. This adventitious shoot regeneration method may be used for large-scale shoot propagation and genetic
engineering studies of S. aculeatissimum. 相似文献
20.
Songul Gurel Mehmet Cengiz Baloglu Ekrem Gurel Huseyin Avni Oktem Meral Yucel 《Plant Cell, Tissue and Organ Culture》2011,106(2):261-268
The effects of a two-stage pretreatment of seedlings on the subsequent shoot regeneration capacity were investigated. Pretreated
seedlings were obtained by germinating seeds on three different germination media and then further culturing on six different growth media. Lamina and petiole explants of two sugar beet (Beta
vulgaris L.) breeding lines were then excised from the pretreated seedlings and cultured on five different shoot regeneration media. In both breeding lines, petiole explants produced significantly more shoots than lamina explants with higher frequencies
of organogenic capacities; petiole explants of the lines M1195 and ELK345 produced a mean of 2.1 and 2.7 shoots per explant
while their lamina explants produced 1.5 and 2.2 shoots per explant, respectively. A genotypic variation was evident as the
line ELK345 was more productive for shoot development from both types of explants. In overall comparisons of different germination, growth and regeneration media, germination medium was most effective when supplemented with 0.5 mg/l 6-benzyladenine (BA) while both growth and regeneration
media were most productive when contained a combination of 0.25 mg/l BA and 0.10 mg/l indole-3-butyric acid (IBA). Of all
the treatments tested, the highest mean number of shoots per explant (8.3 shoots) and frequency of organogenic explants (75.6%)
were obtained on regeneration medium supplemented with 0.25 mg/l BA and 0.10 mg/l IBA when petiole explants of the line ELK345
were excised from the seedlings that had been germinated on medium containing 0.5 mg/l BA followed by further growth on medium
containing 0.25 mg/l BA and 0.10 mg/l IBA. 相似文献