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1.
P. Giridhar Vinod Kumar G. A. Ravishankar 《In vitro cellular & developmental biology. Plant》2004,40(6):567-571
Summary A novel protocol has been developed for inducing somatic embryogenesis from leaf cultures of Decalepis hamiltonii. Callus was obtained from leaf sections in Murashige and Skoog (MS) medium supplemented with α-naphthaleneacetic acid (NAA)+N6-benzyladenine (BA) or 2,4-dichlorophenoxyacetic acid (2,4-D)+BA. Nodular embryogenic callus developed from the cut end of
explants on media containing 2,4-D and BA, whereas compact callus developed on media containing NAA and BA. Upon subsequent
transfer of explants with primary callus onto MS media containing zeatin and/or gibberellic acid (GA3) and BA, treatment with zeatin (13.68μM) and BA (10.65 μM) resulted in the induction of the highest number of somatic embryos directly from nodular tissue. The maturation of embryos
took place along with the induction on the same medium. Embryogenic calluses with somatic embryos were subcultured onto MS
basal medium supplemented with 4.56μM zeatin+10.65 μM BA. After 4wk, more extensive differentiation of somatic embryos was observed. The mature embryos developed into complete
plantlets on growth regulator-free MS medium. A distinct feature of this study is the induction of somatic embryogenesis from
leaf explants of Decalepis hamiltonii, which has not been reported previously. By using this protocol, complete plantlets could be regenerated through indirect
somatic embryogenesis or organogenesis from leaf explants in 12–16 wk. 相似文献
2.
Q. C. Liu H. Zhai Y. Wang D. P. Zhang 《In vitro cellular & developmental biology. Plant》2001,37(5):564-567
Summary Using 15 Chinese and Japanese cultivars of sweetpotato, Ipomoea batatas (L.) Lam., we succeeded in developing an efficient plant regeneration system from embryogenic suspension cultures. The embryogenic
callus derived from shoot apices of the 15 cultivars was used to initiate embryogenic suspension cultures in Murashige and
Skoog (MS) medium containing 9.05 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Rapidly proliferating and well-dispersed embryogenic suspension cultures were established.
Cell aggregates 0.7–1.1 mm in size from embryogenic suspension cultures were transferred to solid MS medium supplemented with
9.05 μM of 2,4-D and formed embryogenic callus with somatic embryos. The embryogenic callus with somatic embryos was further transferred
to MS medium supplemented with 3.78 μM of abscisic acid, resulting in the germination of somatic embryos. Within 20 wk after the initiation, the frequencies of
cell aggregates forming plantlets reached approximately 100% for the 15 tested cultivars. These plantlets, when transferred
to soil, showed 100% survival. No morphological variations were observed. 相似文献
3.
Summary
Kalopanax pictus (Thunb.) Nakai is a tall tree, and its wood has been used in making furniture, while its stem bark is used for medicinal
purposes. Here, we report on the micropropagation of Kalopanax pictus via somatic embryogenesis. Embryogenic callus was induced from immature zygotic embryos. The frequency embryogenic callus
induction is influenced by days of seed harvest. Callus formation was primarily observed along the radicle tips of zygotic
embryos incubated on Murashige and Skoog (MS) medium with 4.4 μM 2,4-dichlorophenoxyacctic acid (2,4-D). Somatic embryogenesis was observed following transfer of embryogenic callus to MS
medium lacking 2,4-D. Somatic embryos at the cotyledonary stage were obtained after 6 wk following culture. Frequency of conversion
of somatic embryos into plantlets was low (35%) on a hormone-free MS basal medium, but it increased to 61% when the medium
was supplemented with 0.05% charcoal. Gibberellic acid (GA3) treatment markedly enhanced the germination frequency of embryos up to 83%. All plantlets obtained showed 98% survival on
moist peat soil (TKS2) artificial soil matrix. About 30 000 Kalopanax pictus plants were propagated via somatic embryogenesis and grown to 3-yr-old plants. These results indicate that production of
woody medicinal Kalopanax pictus plantlets through somatic embryogenesis can be practically applicable for propagation. 相似文献
4.
Summary Regeneration of plants via somatic embryogenesis was achieved from zygotic embryo explants isolated from mature seeds of Schisandra chinensis. Merkle and Sommer's medium, fortified with 2,4-dichlorophenoxyacetic acid (2,4-D; 9.04 μM) and zeatin (0.09 μM), was effective for induction of embryogenic callus. The development of a proembryogenic mass and somatic embryos occurred
on Murashige and Skoog medium (MS) free of plant growth regulators. The embryogenic callus induced on Merkle and Sommer's
medium supplemented with 2,4-D (9.04 μM) and zeatin (0.09 μM) showed development of the maximum number of somatic embryos when transferred to MS medium free of plant growth regulators.
The maximum maturation and germination of cotyledonary somatic embryos (46.3%) occurred on MS medium supplemented with 2,4-D
(0.45 μM) and N6-benzyladenine (1.11 μM). The somatic embryo-derived plants were successfully hardned, with a survival rate of approximately 67%, and established
in the field. 相似文献
5.
T. Chakbavarty J. G. Norcini J. H. Aldrich R. S. Kalmbacher 《In vitro cellular & developmental biology. Plant》2001,37(5):550-554
Summary Creeping bluestem (Schizachyrium scoparium (Michx.) Nash var. stoloniferum (Nash) J. Wipff) embryogenic callus growing on solid medium was used to establish a cell suspension culture in Murashige
and Skoog (MS) basal medium supplemented with 1.5 mg l−1 (6.8 μM) 2,4-dichlorophenoxyacetic acid (2,4-D), 0.2 mg l−1 (0.88 μM) 6-benzylaminopurine (BA), 0.5 mg l−1 (1.4 μM) zeatin, 0.2 mg l−1 (0.58 μM) gibberellic acid (GA3), and 10% (v/v) of coconut water (CW). Pro-embryos from suspension culture matured on semi-solid MS medium in about 18 wk,
and were then cultured on semi-solid MS medium without growth regulators for 2–3 wk. Shoots were regenerated on MS basal medium
supplemented with 3.0 mg L−1 (13.6 μM) 2,4-D, 1.0 mg l−1 (4.4 μM) BA, 1.0 mg l−1 (2.9 μM) GA3, 0.5 mg l−1 (2.7 μM) 1-naphthaleneacetic acid (NAA), 500 mg l−1 easein hydrolysate, and 10% (v/v) CW. Rooted plantlets were successfully accelimatized to greenhouse and outdoor conditions.
Using this protocol, it would be possible to produce at least 1300 fully acclimatized plantlets annually. 相似文献
6.
Summary Sodium chloride-tolerant plantlets of Dendrocalamus strictus were regenerated successfully from NaCl-tolerant embryogenic callus via somatic embryogenesis. The selection of embryogenic
callus tolerant to 100 mM NaCl was made by exposing the callus to increasing (0–200 mM) concentrations of NaCl in Murashige and Skoog medium having 3% (w/v) sucrose, 0.8% (w/v) agar, 3.0 mg l−1 (13.6 μM) 2,4-dichlorophenoxyacetic acid (2,4-D), and 0.5mg l−1 (2.3μM) kinetin (callus initiation medium). The tolerance of the selected embryogenic callus to 100 mM NaCl was stable through three successive transfers on NaCl-free callus initiation medium. The tolerant embryogenic callus
had high levels of Na+, sugar, free amino acids, and proline but a slight decline was recorded in K+ level. The stable 100 mM NaCl-tolerant embryogenic callus differentiated somatic embryos on maintenance medium [MS medium +3% sucrose +0.8% agar +2.0
mg l−1 (9.0 μM) 2,4-D+0.5 mg l−1 (2.3 μM) kinetin] supplemented with different (0–200 mM) concentrations of NaCl. About 39% of mature somatic embryos tolerant to 100 mM NaCl germinated and converted into plantlets in germination medium [half-strength MS+2% sucrose+0.02 mg l−1 (0.1 μM) α-naphthaleneacetic acid +0.1 mg l−1 (0.49 μM) indole-3-butyric acid] containing 100 mM NaCl. Of these plantlets about 31% established well on transplantation into a garden soil and sand (1:1) mixture containing
0.2% (w/w) NaCl. 相似文献
7.
Jameel M. Al-Khayri Feng H. Huang Teddy E. Morelock Tahani A. Busharar 《In vitro cellular & developmental biology. Plant》1992,28(2):64-66
Summary A system for the regeneration of spinach (Spinacia oleracea L.) from mature dry seed explants has been established. The response of two commercial spinach cultivars, ‘Grandstand’ and
‘Baker’, was examined. Callus proliferation was most prominent on MS medium supplemented with 9.3 μM of 6-furfurylaminopurine (kinetin) and 3.39 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Adventitious shoot formation was observed within 8 wk after callus was transferred
onto regeneration medium. Shoot regeneration was best from callus induced on 9.3 μM kinetin and 4.56 μM 2,4-D. The regeneration medium contained 9.3 μM kinetin, 0.045 μM 2,4-D, and 2.89 μM gibberellic acid (GA3). Shoots were rooted on hormone-free medium, and plants grown in a greenhouse showed normal phenotype. This system is beneficial
in rapid propagation of spinach plants, particularly when only a limited number of seeds are available. 相似文献
8.
Wei Tang Zhongchen Guo Fan Ouyang 《In vitro cellular & developmental biology. Plant》2001,37(5):558-563
Summary Mature zygotic embryos of eight (open-pollinated) families of loblolly pine (Pinus taeda L.) were cultured on eight different basal salt formulations, each supplemented with 36.2 μM 2,4-dichlorophenoxyacetic acid, 17.8 μM 6-benzyladenine, 18.6 μM kinetin, 500 mg l−1 casein hydrolysate, and 500 mg l−1
l-glutamine for 9 wk; embryogenic tissue was formed on cotyledons, hypocotyls, and radieles of mature zygotic embryos. Callus
was subcultured on the callus proliferation medium, the same as the induction medium but with one-fifth concentration of auxin
and cytokinin for 9 wk. On this medium a white to translucent, glossy, mucilaginous embryogenic callus containing embryogenic
suspensor masses (ESMs) was obtained. The highest frequency of explants forming embryogenic tissue, 17%, occurred on a modified
Murashige and Skoog salts basal medium containing the concentration of KNO3, Ca(NO3)2·4H2O, NH4NO3, KCl, ZnSO4·7H2O, and MnSO4·H2O, 720, 1900, 400, 250, 25.8, and 25.35 mg l−1, respectively. Embryogenic suspension cultures were established by culturing embryogenic callus in liquid callus proliferation
medium. Liquid cultures containing ESMs were transferred to medium containing abscisic acid, polyethylene glycols, and activated
charcoal for stimulating the production of cotyledonary somatic embryos. Mature somatic embryos germinated for 4–12 wk on
medium containing indole-butyric acid, gibberellic acid, 6-benzyladenine, activated charcoal, and reduced sucrose concentration
(15 g l−1). Two hundred and ninety-one regenerated plantlets were transferred to a perlite:peatmoss:vermiculite (1∶1∶1) mixture, then
the plants were transplanted to soil in the earth, and 73 plantlets survived in the field. 相似文献
9.
Summary Seedlings from 11 seed sources (lines) of American ginseng from different geographic regions were evaluated on Murashige and
Skoog medium (MS) containing 10 μM α-naphthaleneacetic acid (NAA) and 9 μM 2,4-dichlorophenoxyacetic acid (2,4-D) for callus development and somatic embryo formation. Leaf and stem explants callused
at a frequency of 18.2–100%, while somatic embryos were produced from these calluses at a frequency of 25–87.5% after 5 mo.
Suspension cultures of nine lines were established by transferring embryogenic callus to MS liquid medium with NAA and 2,4-D
at 2.5 and 2.25 μM, respectively, and maintained by subcultures every 8 wk. Globular somatic embryos from these cultures were germinated on
half-strength MS containing 1% activated charcoal, and roots >5 mm in length developed within 3 wk. A 7-d exposure to 3 μM gibberellic acid and 5 μM 6-benzylaminopurine significantly enhanced shoot development and promoted further root development. The chromosome number,
profiles of the common triterpenoid saponins (ginsenosides), and random amplified polymorphic DNA (RAPD) banding patterns
in plantlets derived from suspension culture were compared to those of zygotic seedlings. The chromosome number in root tip
cells and suspension cultured cells was 48. Patterns of the six major ginsenosides, determined by thin-layer chromatography,
in leaves of tissue culture-derived plantlets were identical to those in seedlings. RAPD patterns among plantlets originating
from the same tissue-cultured line were mostly identical; however, altered patterns were observed in some lines that had been
maintained in suspension culture for almost 4 yr. The results from this study indicate that propagation of desired ginseng
genotypes in suspension culture can be achieved, and that biochemical and molecular markers can be used for authentication
of resulting plantlets. 相似文献
10.
Summary
In vitro propagation of Andrographis paniculata (Burm. f.) Wallich ex Nees through somatic embryogenesis, and influence of 2,4-dichlorophenoxyacetic acid (2,4-1) on induction, maturation, and
conversion of somatic embryos were investigated. The concentration of 2,4-D in callus induction medium determined the induction,
efficacy of somatic embryogenesis, embryo maturation, and conversion. Friable callus initiated from leaf and internode explants
grown on Murashige and Skoog (MS) medium supplemented with 2.26, 4.52, 6.78, and 9.05μM 2,4-D started to form embryos at 135, 105, 150, and 185d, respectively, after explant establishment. Callus initiated at
13.56μM 2,4-D did not induce embryos even after 240 d, whereas those initiated on MS medium with 4.52μM 2,4-D was most favorable for the formation and maturation of somatic embryos. Callus subcultured on the medium with reduced
concentration of 2,4-D (2.26μM) became embryogenic. This embryogenic callus gave rise to the highest number of embryos (mean of 312 embryos) after being
transferred to half-strength MS basal liquid medium. The embryos were grown only up to the torpedo stage. A higher frequency
of embryos developed from callus initiated on 2.26 or 4.52 μM 2,4-D underwent maturation compared to that initiated on higher concentrations of 2.4-D. The addition of 11.7μM silver nitrate to half-strength MS liquid medium resulted in 71% of embryos undergoing maturation, while 83% of embryos developed
into plantlets after being transferred to agar inedium with 0.44 μMN6-benzyladenine and 1.44 μM gibberellic acid. Most plantlets (88%) survived under field conditions and were morphologically identical to the parent plant. 相似文献
11.
Summary A protocol was developed for high frequency somatic embryogenesis and plant regeneration from cotyledon and hypocotyl explants
of Eruca sativa. Explants grown on Murashige and Skoog (MS) medium supplemented with 4.52 μM 2,4-D formed embryogenic callus after 4 wk of culture. Secondary somatic embryos were also produced from primary somatic
embryos on MS medium containing 0.56 μM 2,4-D. Somatic embryos developed into mature embryos on MS medium in the presence of 45 gl−1 polyethylene glycol. After desiccation, somatic embryos developed into plantlets by culturing the mature somatic embryos
on 1/2 x MS medium containing 0.24 μM indole-3-butyric acid. 相似文献
12.
G. Vengadesan N. Selvaraj R. Prem Anand V. Gaba A. Ganapathi 《In vitro cellular & developmental biology. Plant》2005,41(6):789-793
Summary Suspension culture of cucumber (Cucumis sativus L.) has been an inefficient method for production of somatic embryos owing to problems with embryo maturation and conversion.
Embryogenic callus of cv. Green Long was induced on semisolid Murashige and Skoog (MS) medium containing 6.8 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.2 μM 6-benzylaminopurine (BA). A large number of globular somatic embryos were obtained on transfer of the callus to MS liquid
medium supplemented with 87.6 mM sucrose, 1.1 μM 2,4-D, and improved by the addition of 342.4 μM
l-glutamine. MS medium supplemented with 87.6 mM sucrose was more effective in somatic embryo production than other sugars. Subsequent development led to the formation of
heart-and torpedo-shaped embryos. Maturation of somatic embryos occurred on plant growth regulator-free MS semi-solid medium
containing 175.2 mM sucrose and 0.5 gl−1 activated charcoal. Conversion of embryos into plants was achieved on half-strength MS semi-solid medium containing 87.6
mM sucrose and 1.4 μM gibberellic acid (GA3) in a 16h photoperiod. Twenty-seven percent of embryos were converted into normal plants. 相似文献
13.
Summary Indirect somatic embryogenesis, encapsulation, and plant regeneration was achieved with the rare rhoeophytic woody medicinal
plant Rotula aquatica Lour. (Boraginaceae). Friable callus developed from leaf and internode explants on Murashige and Skoog (MS) medium with 0.45 μM 2,4-dichlorophenoxyacetic, acid (2,4-D) was most effective for the induction of somatic embryos. Subculture of the callus
onto half-strength MS medium with the same concentration of 2,4-D resulted in highly embryogenic callus. Suspension culture
was superior to solid medium culture for somatic embryogenesis. Embryogenic callus.during subsequent transfer to suspension
cultures of half-strength MS medium having 0.23 μM 2,4-D induced the highest number of somatic embryos (a mean of 25.6 embryos per 100 mg callus) and the embryos were grown
up to the torpedo stage. Transfer of embryos to half-strength MS basal solid medium allowed development, of 50% of the embryos
to the cotyledonary stage. Of the cotyledonary embryos, 90% underwent conversion to plantlets on the same medium. Encapsulated
cotyledonary embryos exhibited 100% conversion to plantlets. Ninety-five percent of the plantlets established in field conditions
survived, and were morphologically identical to the mother plant. 相似文献
14.
M. Gallo-Meagher R. G. English A. Abouzid 《In vitro cellular & developmental biology. Plant》2000,36(1):37-40
Summary Efficient shoot regeneration of sugarcane (Saccharum spp. hybrid cv. CP84-1198) from embryogenic callus cultures has been obtained using thidiazuron (TDZ). Callus was placed
on modified Murashige and Skoog (MS) medium containing 2.3 μM 2,4-dichlorophenoxyacetic acid (2,4-D), or 9.3 μM kinetin and 22.3 μM naphthaleneacetic acid (NAA) and compared with the same MS medium supplemented with 0.5, 1.0, 2.5, 5.0 or 10.0 μMTDZ, A11 TDZ treatments resulted in faster shoot regeneration than the kinetin/NAA treatment, and more shoot production than
either the 2,4-D or kinetin/NAA treatments. Maximum response, as determined by total number of shoots (26 per explant) and
number of shoots greater than 1 cm (4 per explant) 4 wk after initiation, was obtained with 1.0 μM TDZ. The shoots rooted efficiently on MS medium supplemented with 19.7 μM indole-3-butyric acid (IBA). These results indicate that TDZ effectively stimulates sugarcane plant regeneration from embryogenic
callus, and may be suitable to use in genetic transformation studies to enhance regeneration of transgenic plants. 相似文献
15.
Ashok Kumar Sahrawat Suresh Chand 《In vitro cellular & developmental biology. Plant》2001,37(1):55-61
Summary An efficient method was established for high-frequency embryogenic callus induction and plant regeneration from 3-,4-, 5-
and 7-d-old coleoptile segments of Indica rice (Oryza sativa L. cv. Kasturi), Compact and friable callus developed from the cut ends and also on the entire length of the coleoptile segments
cultured on Murashige and Skoog (MS) basal medium (1962) supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D, 4.50–18.0
μM), kinetin (2.32 μM) and sucrose (3%, w/v). High frequency embryogenic callus induction and somatic embryo development was achieved when embryogenic
calluses were transferred to MS medium supplemented with 2.25 μM 2,4-D, 2.32 μM kinetin, 490 μM
L-tryptophan and 3% (w/v) sucrose. Plant regeneration was achieved by transferring clumps of embryogenic callus onto MS medium
containing 2.85 μM indole-3-acetic acid (IAA), 17.77 μM 6-benzylaminopurine (BA) and 3% (w/v) sucrose. Histological observations of embryogenic calluses revealed the presence of
somatic embryos and also plant regeneration via multiple shoot bud formation. Three, 4- and 5-d-old coleoptile segments showed
a significantly (P<0.05) higher frequency of plant regeneration and mean number of plantlets per explant in comparison to 7-d-old coleoptile
segments. The highest frequency (73.5%) of plant regeneration and mean number of plantlets (11.9±1.0) was obtained from 4-d-old
coleoptile segments. Regenerated shoots were rooted on MS basal medium containing 4.92 μM indole-3-butyric acid (IBA) and plants were successfully transferred to soil and grown to maturity. 相似文献
16.
Murugesan Dhandapani Seung-Beom Hong Channa Reddy Aswath Doo Hwan Kim 《In vitro cellular & developmental biology. Plant》2008,44(1):8-13
We have optimized conditions for efficient regeneration of the vegetatively propagated zoysia grass (Zoysia matrella L. Merr) cultivar “Konhee”. Two explants, young inflorescences, and stem nodes, were used and they displayed different responses
to combinations and concentrations of plant growth regulators in callusing, embryogenic callus formation, and regeneration.
The highest callus initiation rate from young inflorescences was obtained on medium supplemented with 4.5 to 9.0 μM 2,4-dicholorophenoxy
acetic acid (2,4-D) and 0.44 μM 6-benzyl amino purine (BA). When the BA concentration was lowered to 0.044 μM, the highest
percent embryogenic callus induction from young inflorescences was achieved. The highest callus initiation rate from stem
nodes was obtained, when young inflorescences were cultured on MS medium supplemented with 4.5 to 9.0 μM 2,4-D, 0.44 μM BA,
and 0.037 μM abscisic acid (ABA). But embryogenic callus formation from the stem node was highest in the presence of 4.5 to
9.0 μM 2,4-D, 0.044 μM BA, and 0.037 μM ABA. Addition of ABA significantly increased embryogenic callus formation from stem
nodes, but not from young inflorescences. Regeneration percentage was variable in response to BA level, and inclusion of α-naphthalene
acetic acid (NAA) and gibberellic acid (GA3) further increased the regeneration percentage. The highest regeneration percentages obtained from the young inflorescences
and stem nodes were 82% and 67%, respectively. This is the first report showing that plants can be regenerated from young
inflorescences and stem nodes of vegetatively propagated zoysia grass. 相似文献
17.
Summary Efficient in vitro propagation of Ceropegia candelabrum L. (Asclepidaceae) through somatic embryogenesis was established. Somatic embryogenesis depended on the type of plant growth
regulators in the callus-inducing medium. Friable callus, developed from leaf and internode explants grown on Murashige and
Skoog (MS) medium supplemented with 4.52μM2,4-dichlorophenoxyacetic acid (2,4-D), underwent somatic embryogenesis. Compared to solid media, suspension culture was superior
and gave rise to a higher number of somatic embryos. Transfer of the friable callus developed on MS medium containing 4.52μM 2,4-D to suspension cultures of half- or quarter-strength MS medium with lower levels of 2,4-D (0.23 or 0.45 μM) induced the highest number of somatic embryos, which developed up to the torpedo stage. Somatic embryogenesis was asynchronous
with the dominance of globular embryos. About 100 mg of callus induced more than 500 embryos. Upon transfer to quarter-strength
MS agar medium without growth regulators, 50% of the somatic embryos underwent maturation and developed into plantlets. Plantlets
acclimatized under field conditions with 90% survival. 相似文献
18.
R. Prem Anand A. Ganapathi V. Ramesh Anbazhagan G. Vengadesan N. Selvaraj 《In vitro cellular & developmental biology. Plant》2000,36(6):475-480
Summary Embryogenic callus was induced from primary leaves of Vigna unguiculata (L.) Walp. in MS medium (Murashige and Skoog, 1962) containing 2,4-dichlorophenoxyacetic acid (2,4-D). Greenish-white, friable
embryogenic calluses were used to establish suspension cultures. A shaking speed of 90 rpm and 0.4 ml packed cell volume per
25 ml medium were found to be optimal for maintaining suspension cultures. Globular, heart-shaped and torpedo-shaped embryos
were developed in suspension culture containing 4.52 μM 2,4-D. Maturation of cotyledonary-stage somatic embryos was achieved on 0.05 μM 2,4-D, 5 μM abscisic acid and 3% mannitol. Twenty-two percent of the embryos were converted into plants and survived; survival in the
field was 8–10%. 相似文献
19.
A. Tirajoh T. S. Kyung Z. K. Punja 《In vitro cellular & developmental biology. Plant》1998,34(3):203-211
Summary Somatic embryogenesis in American ginseng (Panax quinquefolium L.) was investigated from three explant sources (root, leaf and epicotyl) with Murashige and Skoog (MS) medium containing
different growth regulators. Mature roots and leaves obtained from 3- to 5-yr-old field-grown plants, and seedling leaves
and epicotyls from plantlets grownin vitro, were evaluated. From root and epicotyl explants, callus development was optimal with 3,6-dichloro-o-anisic acid (dicamba)
(9.0 μM) and kinetin (KN) (5.0 μM) as the growth regulators. When these calluses were transferred after 3 mo. to dicamba alone (9.0 μM), somatic embryo formation was observed at an average frequency of 15.6% in root explants after an additional 3 mo., and
2% in epicotyl explants after an additional 6 mo. No plantlets were recovered because the embryos germinated to form shoots
with no roots. From leaf explants, callus growth was optimal with α-naphthaleneacetic acid (NAA) at 10.0 μM and 2,4-dichlorophenoxyacetic acid (2,4-D) at 9.0 μM. Somatic embryos developed on this medium, with the highest frequency (40%) obtained after 3 mo. from seedling-leaf explants.
Calluses on mature leaves formed somatic embryos after 7 mo. with NAA/2,4-D at an average frequency of 30%. Transfer of these
somatic embryos to 6-benzyladenine/gibberellic acid (4.4/2.9 μM) promoted shoot development but no roots were observed. Up to 100% of germination was observed within 6 wk on half-strength
MS salts containing activated charcoal (1%) and on NAA/2,4-D (5.0/4.5 μM) with charcoal (1%). On the latter medium, somatic embryos enlarged and frequently gave rise to new somatic embryos after
a brief callusing phase. The embryos germinated through a two-stage process, involving the elongation of the root followed
by the formation of a shoot. The highest recovery of ginseng plantlets from germinated embryos was 61.0%. Following transfer
to potting medium and maintenance under conditions of high humidity and low light intensity, the plantlets elongated and developed
new leaves. A high percentage (50%) of these plants have been acclimatized to soil. 相似文献
20.
Hairy roots of Panax ginseng were obtained after root disks were infected with wild-type strain Agrobacterium rhizogenes 15834. Three lines of hairy roots with different pigmentation were selected. Embryogenic callus was induced on Murashige
and Skoog medium containing 1.0 mg/l 2,4-D. The frequency of embryogenic callus formation was 37.4% in a line with red pigmentation.
Somatic embryo development from embryogenic callus was efficiently achieved by lowering the concentration of 2,4-D (0.5 mg/l).
After the germination of somatic embryos on medium with 10 mg/l GA3, the embryos were transferred to 1/2-MS medium without GA3. The transformed ginseng plantlets had an actively growing root system with abundant lateral roots. The phenotypical alteration
of transformed ginseng plants might be valuable character for increasing root yield.
Received: 27 March 1999 / Revision received: 18 May 1999 / Accepted 8 July 1999 相似文献