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1.
Małgorzata Malik 《Plant Cell, Tissue and Organ Culture》2008,94(3):337-345
Alternative procedures for the production of Narcissus L. somatic embryos were investigated. Somatic embryogenesis was initiated on ovary explants isolated from cv. Carlton bulbs,
chilled for 12 weeks at 5°C. The explants were cultured on MS media with 3% sucrose and growth regulators: Picloram or 2,4-D
(10 or 25 μM) and BA (1 or 5 μM) for 12 weeks in the culture systems: continuous cultivation on solid media, continuous cultivation
in liquid media and sequential cultivation using cycles in liquid and solid media. Two types of somatic embryogenesis, indirect
and direct, were observed. The developmental pathway depended on the period of exposure to liquid media. Somatic embryos were
formed via embryogenic nodular callus on solid media. 2,4-D and BA stimulated the process. The 4-week and 8-week liquid medium
treatments resulted in the development of somatic embryos directly from the ovary explant tissue. The highest number of somatic
embryos was noted under the influence of 25 μM 2,4-D and 5 μM BA in explants cultivated for 8 weeks in liquid medium and then,
for 4 weeks, on solid medium. The effects of inoculum density on biomass increase and the formation of somatic embryos in
cultures obtained on a medium with 25 μM 2,4-D and 5 μM BA were also checked. The highest biomass increase was observed after
subculturing in liquid medium containing 0.5 μM NAA and 5 μM BA when the density of inoculum was 0.5 g/25 ml of the medium.
The highest number of somatic embryos was noted when the density of inoculum was 1.5 g/25 ml. 相似文献
2.
Y. J. Kim M. K. Kim J. S. Shim R. K. Pulla D. C. Yang 《Russian Journal of Plant Physiology》2010,57(2):283-289
Somatic embryogenesis from single cells is important for normal plant regeneration of ginseng. Cotyledon explants from zygotic
embryos of two new ginseng cultivars, Chun-Poong and Yun-Poong, produced somatic embryos on Murashige and Skoog (MS) basal
medium and MS medium containing growth regulators. The highest frequency of single somatic embryo formation was obtained when
cotyledon explants were excised from premature (cultured for 1 day) zygotic embryos (about 6 mm in length) of both cvs. Chun-Poong
and Yun-Poong and then cultured on MS medium supplemented with 7% sucrose. The frequency of single somatic embryo formation
was strongly enhanced when Chun-Poong cotyledons were subjected to plasmolysis with 0.1–0.5 M sucrose for 24 h and Yun-Poong
cotyledons to plasmolysis with 1.0 M sucrose for 24 h and then cultured on MS medium with 2,4-D. 相似文献
3.
Veena Agrawal Pratima Rani Sardar 《In vitro cellular & developmental biology. Plant》2007,43(6):585-592
In vitro regeneration through somatic embryogenesis as well as organogenesis using cotyledon of a woody medicinal legume, Cassia angustifolia is reported. The cotyledons dissected from semi-mature seeds, if inoculated on Murashige and Skoog’s medium (MS) supplemented
with auxin alone or in combination with cytokinin, produced direct and indirect somatic embryos. A maximum of 14.36 ± 2.26
somatic embryos per 20 mg of explants including callus were produced in 70% cultures on MS medium with 2.5 μM benzyladenine
(BA) + 10 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Although the percentage of embryogenic cultures was higher (83.33%) at
10 μM 2,4-D + 1 μM BA, the average number of somatic embryos was much less (7.6 ± 0.85) at this level, whereas at 2.5 μM BA
and 5 μM 2,4-D, there was a simultaneous formation of both somatic embryos and shoots. The somatic embryos, although started
germinating on the same medium, developed into full plantlets only if transferred to MS basal with 2% sucrose. Cytokinins
alone did not induce somatic embryogenesis, but formed multiple shoots. Five micromolar BA proved optimum for recurrently
inducing shoots in the competent callus with a maximum average of 12.04 ± 2.10 shoots and shoot length of 2.26 ± 0.03 cm.
Nearly 91.6% shoots (2–2.5 cm in size) organized an average of 5.12 ± 0.58 roots on half strength MS + 10 μM indole-3-butyric
acid. All the plantlets have been transferred successfully to soil. Types of auxin and its interaction with cytokinin significantly
influenced somatic embryogenesis. 相似文献
4.
We elucidated the relationship between cell proliferation and somatic embryogenesis in the culture of carrot cotyledons. Fresh
weights of the cotyledon expiants were determined every five days while being cultured on a medium containing 2,4-D. Callus
production increased exponentially from Day 20 to Day 25, showing a two-fold rate of proliferation. To examine the embryogenic
potential of the callus, we pre-cultured cotyledon explants on an MS medium with 2,4-D, then transferred them to an MS basal
medium at five-day intervals. Somatic embryos formed most frequently when the cotyledons were pre-cultured for 20 days on
an MS medium that contained 5 μ2,4-D. The frequency of somatic embryo formation was 81%, while that of normal embryos with
two cotyledons was 51% among those formed on a hormone-free medium. We used FACScan analysis to relate the embryogenic potential
of the callus to the S phase in the cell cycle of cultured cells. The S phase was high after 25 days of culture on the medium
with 5 μM 2,4-D. In contrast, the frequency of normal embryogenesis was higher at Day 20 of the pre-culture period. Culturing
embryogenic calli on a medium with 5 μM 2,4-D was most favorable for producing somatic embryos with two cotyledons. We verified
that active somatic embryogenesis was apparently related to cell division activity; somatic embryos induced from actively
dividing cells were apt to accompany cotyledonary abnormality. 相似文献
5.
Waxflowers (Chamelaucium spp.) are native to Australia and now are grown for the cut flower industry worldwide. As part of an effort to achieve somatic
hybridization between the species to improve flower quality, somatic embryogenesis was achieved for Chamelaucium uncinatum and C. repens. Somatic embryos from young leaves of C. uncinatum and C. repens were induced in vitro on Murashige and Skoog (MS) agar medium containing 20 g/l sucrose and 2,4-dichlorophenoxyacetic acid
(2,4-D). For C. uncinatum, up to 4% of explants developed somatic embryos at 20 μM 2,4-D and for C. repens, up to 3% developed somatic embryos at 5 μM 2,4-D. Somatic embryos of C. uncinatum were also induced from immature seeds—a maximum of 6% of seed explants producing somatic embryos on MS medium containing
0.05 μM 6-benzyladenine (BA) and 0.5 μM Naphthalene acetic acid (NAA). Somatic embryo cultures maintained on MS medium supplemented
with 0.1 μM 2,4-D were induced to develop into plantlets after transfer to a hormone-free medium under light. 相似文献
6.
In the present study, the procedures for induction of somatic embryogenesis (SE) in an in vitro culture of the tulip have been developed. SE was initiated on flower stem explants isolated from “Apeldoorn” bulbs during
their low-temperature treatment. Bulbs had not been chilled or had been chilled for 12 or 24 weeks at 5°C. The explants were
cultured with exogenous auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (Picloram), α-naphthaleneacetic
acid (NAA) at 1–100 μM and cytokinins: benzyladenine (BA) and zeatin (ZEA) at 0.5–50 μM. Increase in auxin concentrations
caused an intensive enlargement of the explant parenchyma, which changed into homogenous colorless callus. On the same media,
vein bundles developed into yellowish, nodular callus. Picloram was more efficient in inducing the formation of embryogenic
nodular callus than 2,4-D, whereas the latter stimulated formation of colorless callus. The base of the lower part of the
flower stem isolated from bulbs chilled for 12 weeks proved to be the best explant for callus formation. The highest number
of somatic embryos was produced on medium with 25 μM Picloram and 0.5 μM BA. Development of adventitious roots was noticed
in the presence of 2,4-D. Globular embryos developed into torpedo stage embryos under the influence of BA (5 μM) and NAA (0.5 μM).
Morphological and anatomical data describing development of callus and somatic embryos are presented. 相似文献
7.
High-efficiency somatic embryogenesis and plant regeneration from suspension cultures of grapevine 总被引:10,自引:0,他引:10
Embryogenic suspensions of grapevine (Vitis vinifera L.) were initiated from somatic embryos of `Thompson Seedless' and `Chardonnay'. Suspension cultures consisted of proembryonic
masses (PEM) that proliferated without differentiation in a medium containing 2,4-dichlorophenoxyacetic acid (2,4-D). `Chardonnay'
somatic embryos developed fully from PEMs following subculture in medium without 2,4-D; however, somatic embryo development
did not advance beyond the heart stage in `Thompson Seedless' suspension cultures. Highly synchronized development of somatic
embryos was obtained by inoculating <960-μm PEMs into liquid medium without 2,4-D. Somatic embryos were also produced in large
numbers from suspension-derived PEMs of both cultivars on semisolid medium lacking 2,4-D. Somatic embryos matured and regenerated
into plants in MS basal medium containing 3% sucrose. Using this method more than 60% of the somatic embryos regenerated plants.
More than 90% of the regenerated plants were successfully transferred to the greenhouse.
Received: 27 July 1998 / Revision received: 15 October 1998 / Accepted: 27 October 1998 相似文献
8.
Summary Suspension cultures initiated from calluses derived from seedling leaf explants of Acacia sinuata (Lour.) Merr. produced somatic
embryos. Embryogenic callus was induced on semisolid MS (Murashige and Skoog, 1962) medium supplemented with 4.52 μM 2,4-dichlorophenoxyacetic
acid (2,4-D) and 2.22 μM 6-benzylaminopurine. A high frequency of somatic embryos was induced in MS liquid medium supplemented
with 4.52 μM 2,4-D and 10% coconut water. Further studies on ontogeny of somatic embryos showed that the cells destined to
become somatic embryos divided into spherical proembryos. Subsequent development led to the formation of globular, heart,
torpedo-shaped and cotyledonary-stage embryos. The conversion of somatic embryos occurred on auxin-free MS medium. Effects
of various auxins, cytokinins, carbohydrates and amino acids in enhancing productin, of somatic embryos were studied. MS medium
supplemented with 87.64 mM sucrose and 342.46 μM glutamine promoted higher somatic embryo production whereas cytokinin had
no effect and led to recallusing of embryos. About 8–10% of embryos converted into plants. 相似文献
9.
Summary Pepper (cv. New Mexico — 6 and Rajur Hirapur) plants were regenerated from immature zygotic embryos via direct somatic embryogenesis. Somatic embryos were formed directly, without any intervening callus, on the zygotic embryo apex, embryo axis and cotyledons on Murashige and Skoog's (MS) medium containing 2,4-D (418 M), thidiazuron (10 M) and a high concentration of sucrose (6–10%). The best response was observed on MS medium containing 2,4-D (9 M), coconut water (10%) and high sucrose (8%). The entire process of induction and maturation of the embryos was completed on the same medium. Histological examination indicated that secondary embryogenesis also occurred directly from the primary somatic embryos. Differentiation of embryos was nonsynchronous, and some embryos were swollen and distorted with fasciation. More than 70% of the mature normal somatic embryos germinated readily on MS medium containing GA3 or TDZ, alone and in combination, and following transfer to pots developed into normal plants.Abbreviations CM
Coconut milk
- 2,4-D
2,4-dichlorophonoxyacetic acid
- GA3
gibberellic acid
- MS
Murashige and Skoog (1962) medium
- NAA
napthaleneacetic acid
- TDZ
thidiazuron 相似文献
10.
Douglas A. Steinmacher Charles R. Clement Miguel P. Guerra 《Plant Cell, Tissue and Organ Culture》2007,89(1):15-22
Various factors affect the induction of somatic embryogenesis in peach palm (Bactris gasipaes Kunth). Among these, both the type and level of auxins had the greatest influence on in vitro responses, although the genotype
and the developmental stage of the explants also influenced results. Younger inflorescences were more competent to respond
to SE induction than more mature inflorescences and the use of a pre-treatment with 2,4-D (200 μM) in liquid MS culture medium
also increased the embryogenic capacity, and diminished the development of flower buds. Higher oxidation rates were observed
in explants maintained on 2,4-D-supplemented culture medium, while on 300 μM or 600 μM Picloram and Dicamba lower oxidation
rates were observed. The progression from floral meristem to flower bud occurred at high frequency when low concentrations
of auxins were used, independent of the type. Higher concentrations of Picloram or Dicamba reduced or even inhibited flower
bud development. Picloram also enhanced the embryogenic induction rate more than 2,4-D and Dicamba, and among the concentrations
evaluated 300 μM Picloram enhanced induction for both genotypes, with significant differences between genotypes. The best
combination of variables used the least mature inflorescence (Infl1) from genotype I with the 2,4-D pre-treatment and 300 μM Picloram to generate 5 embryogenic calli from 18 explants; 26 embryos
were obtained on average from each embryogenic callus. From these, eighteen embryos converted to plantlets and six of these
survived transfer to the greenhouse. 相似文献
11.
Summary Somatic embryos of pineapple guava (Feijoa sellowiana Berg, Myrtaceae) were induced particularly well from the adaxial face of the cotyledons of zygotic embryos cultured on MS medium containing 1.0 mg/l 2,4-D and 0.3 M sucrose. Somatic embryos were never obtained from globular and heart-shaped zygotic embryos and embryos at the torpedo stage produced somatic embryos at lower frequencies than mature zygotic embryos. At the time of explantation, cotyledonary cells were rich in storage proteins and lipids but no starch was found. After the first 5 days of culture most of the reserves had been mobilized in cotyledons of germinating embryos, but were still present in large amounts in cotyledons undergoing embryogenie induction. In contrast to cotyledons following the normal pattern of development, cells of embryogenically-induced cotyledons accumulated starch, especially those cells not involved in the embryogenie process. Two patterns of somatic embryo differentiation were observed: (1) from single epidermal cells or (2) from groups of meristematic cells near the adaxial surface. Comparative observations on cotyledons from germinating embryos and those undergoing embryogenesis suggest that the meristematic layer arises as the result of successive divisions of cells that, under normal conditions, would form the palisade parenchyma. These were the only mesophyll cells that showed mitotic divisions during the normal development.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- FAA
formalin/acetic acid/ethyl alcohol
- PAS
periodic acid-Schiff 相似文献
12.
Maggie Panaia Eric Bunn Jen McComb 《In vitro cellular & developmental biology. Plant》2011,47(3):379-386
Somatic embryogenesis was developed as a method of mass propagation for Lepidosperma drummondii (Cyperaceae), a difficult to propagate but important species for post-mining restoration in a region of high plant biodiversity,
in the southwest of Western Australia. Cultures were initiated from excised zygotic embryos, shoot cultures to rhizomes. Only
zygotic embryos of L. drummondii developed somatic embryos, with half strength Murashige and Skoog basal medium (BM) and 1 μM 2,4-dichlorophenoxyacetic acid
(2,4-D) being the most effective combination. The first culture cycle yielded a mean of 30 somatic embryos per excised zygotic
embryo forming an embryo cluster. After a further 6 wk in culture (on fresh BM with 1 μM 2,4-D), approximately 350 somatic
embryos per starting embryo cluster were recorded. Following regular sub-culturing of primary somatic embryo clusters onto
fresh media (every 4 wk), more than 74,000 secondary somatic embryos were estimated to have been produced after eight subculture
periods. This translates to between 1,000 and 2,000 somatic embryos produced from an estimated 45 mg of starting tissue per
culture plate or potentially 22,0000–44,000 somatic embryos per gram of tissue. This is a significant improvement over all
previous methods used to propagate L. drummondii, in which typical in vitro shoot multiplication rates are as low as 1.43 per 8 wk. This also compared favourably with published data and concurrent
experiments undertaken in this study (as an extra control measure) on somatic embryo production for a related species Baloskion tetraphyllum (using the same BM with 1 μM 2,4-D and coleoptile segments as explants). Various media combinations were investigated for
efficacy in converting somatic embryos into plants with best results ranging from 86% to 100% conversion for B. tetraphyllum on BM without plant growth regulators. Development of L. drummondii somatic embryos into plants was not observed on BM without plant growth regulators. However, a best result of 39% conversion
to plants was observed on BM with 1 μM thidiazuron. This is the first report of successful development of somatic embryogenesis
and conversion of somatic embryos into plants using thidiazuron for the Australian cyperale L. drummondii. 相似文献
13.
An efficient plant regeneration procedure has been established from hypocotyl explants of the common ice plant, Mesembryanthemum crystallinum L, a halophytic leaf succulent that exhibits a stress-induced switch from C3 photosynthesis to crassulacean acid metabolism
(CAM). Somatic embryos were initiated and developed up to globular and heart stages in Murashige and Skoog (MS) media supplemented
with 3% sucrose, 0.6% bacto-agar, 80 mM NaCl, 5 μM 2,4-D and 1 μM kinetin. High frequency regeneration occurred when somatic
embryos were germinated on media that lacked 2,4-D. High cytokinin treatment suppressed normal growth of embryos and favored
abnormal embryo proliferation. Without growth regulators, regenerated plants rooted on MS medium with 100% efficiency. Mature,
regenerated plants were fertile and morphologically identical to seed-derived plants.
Received: 29 April 1999 / Revision received: 2 July 1999 · Accepted: 12 July 1999 相似文献
14.
Hypocotyl segments ofEleutherococcus senticosuscultured on Murashigeand Skoog's (MS) medium with 4.5 µM2,4-D produced somaticembryos directly from the surface of explants without interveningcallus formation. When these somatic embryos were subculturedto the same MS medium with 4.5 µM2,4-D, friable embryogeniccalli were formed mainly from radicle tips of somatic embryos,but at a low frequency (5%). Selected embryogenic calli weremaintained on MS agar or liquid medium with 4.5 µM2,4-D.To induce somatic embryo development, embryogenic calli andcell clumps were transferred to MS medium lacking 2,4-D. Thefrequency of somatic embryo formation differed between culturetypes with 1570 embryos formed per Petri dish from callus cultureand 5514 embryos formed per flask from cell suspension cultures.Somatic embryos formed on agar medium had larger cotyledonsthan those of embryos formed in liquid medium. GA3treatmentwas necessary to induce germination from somatic embryos. Therate of plant conversion was 97% in somatic embryos from callusculture and 76% in embryos from liquid culture. Regeneratedplantlets were successfully acclimatized in the glasshouse.Copyright1999 Annals of Botany Company Eleutherococcus senticosus, micro propagation, somatic embryogenesis. 相似文献
15.
Jing Li Yang Yu Da Niu Chuan Ping Yang Gui Feng Liu Cheng Hao Li 《Plant Cell, Tissue and Organ Culture》2011,106(3):391-399
Somatic embryogenesis (SE) was induced in female flower buds from mature Schisandra chinensis cultivar ‘Hongzhenzhu’. Somatic embryo structures were induced at a low frequency from unopened female flower buds and excised
unopened on Murashige and Skoog (MS) agar medium containing 4.0 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D). Friable embryogenic calli were induced from somatic embryo structures after three
to four subcultures on initiation medium. The frequencies of mature somatic embryo germination and plantlet conversion were
low, but increased in the presence of gibberellic acid (GA3). Some germinated somatic embryos could form friable embryogenic calli on medium without plant growth regulators (PGRs).
The germination and conversion frequencies of somatic embryos from embryogenic calli induced using PGR-free medium were higher
than for somatic embryos from embryogenic calli induced on medium containing 2,4-D. Most somatic embryos from 2,4-D-induced
embryogenic calli had trumpet-shaped embryos, and most somatic embryos from PGR-free medium–induced embryogenic calli had
two or three cotyledons. Histological observation indicated that two- and three-cotyledon embryos had defined shoot primordia,
but most of the trumpet-shaped embryos yielded plantlets that lacked or had poorly developed meristem tissue. Cytological
and random amplification of polymorphic DNA (RAPD) analyses indicated no evidence of genetic variation in the plantlets of
somatic embryo origin. 相似文献
16.
We describe a protocol for somatic embryogenesis of Protea cynaroides, with potential for high frequency production of this important horticultural species. Somatic embryos formed directly on
both P. cynaroides mature zygotic embryos and excised cotyledons cultured on MS medium without growth regulators. The addition of growth regulators
such as naphthalene acetic acid (NAA) (5; 13 and 27 μM) and 2,4-dichlorophenoxyacetic acid (2,4-D) (5; 11 and 23 μM), in combination
with thidiazuron (TDZ) (1 μM), benzylaminopurine (BAP) (1 μM) or kinetin (1 μM) suppressed the formation of somatic embryos.
After eight weeks in culture, formation of somatic embryos was observed. Zygotic explants formed the most embryos when cultured
in a 12-h photoperiod in comparison to explants cultured in the dark. Up to 83% of these embryos germinated after transferal
to the germination medium containing 0.3 μM GA3. Significantly fewer embryos germinated in MS medium with no growth regulators, or supplemented with higher concentrations
of GA3, while low germination percentages were also observed in MS media containing casein hydrolysate and coconut water. The germination
of normal somatic embryos (two separate cotyledons and a single radicle) was observed only in media containing either no growth
regulators, 0.3 μM GA3 or 1 μM GA3. All embryos that germinated in high concentrations of GA3 were malformed. 相似文献
17.
Somatic embryos were induced on roots excised from in vitro plants of Prunus avium× pseudocerasus `Colt'. On medium containing 6-benzylamino purine (BAP, 1.5 μM) and 2,4-dichlorophenoxyacetic acid (2,4-D, 15 μM), a mean
of 25 (s.e. ± 2.0) somatic embryos were produced on intact root systems and 15 (s.e. ± 1.7) on roots systems cut into 10 mm
pieces. Most somatic embryos were formed directly on intact roots and indirectly (from callus) on sectioned roots. A mean
of 2.5 (s.e. ± 0.25) secondary embryos per primary embryo were formed directly on primary embryos after they were transferred
to medium containing BAP (1.5 μM), indole-3-butyric acid (10 μM) and 2,4-D (5 μM). After transfer to a medium containing BAP
(2 μM) and gibberellic acid (GA3, 3 μM), shoots developed in 75% (s.e. ± 7.3) of the embryos. Somatic embryos were not induced on explants of in vitro roots or shoots of P. avium, and were induced infrequently on zygotic embryos, although a wide range of media were tested. Possible reasons for the contrasting
embryogenic ability of `Colt' and P. avium are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
M. A. K. Azad S. Yokota F. Begum N. Yoshizawa 《In vitro cellular & developmental biology. Plant》2009,45(4):441-449
Somatic embryogenesis and subsequent plant regeneration were established from hypocotyl and internode explants collected from
in vitro-grown seedlings and in vitro-proliferated shoots, respectively. Somatic embryogenesis was significantly influenced by the types of auxin and cytokinin.
Friable calluses with somatic embryos developed well in Murashige and Skoog basal (MS) medium supplemented with 0.8–8.8 μM
6-benzylaminopurine (BA) and 2.0–8.0 μM 2,4-dichlorophexoxyacetic acid (2,4-D) or α-naphthaleneacetic acid (NAA). The maximal
frequency of embryogenic callus and somatic embryo formation were obtained when the MS medium was amended with 8.8 μM BA and
4.0 μM 2,4-D. The best embryo germination occurred in a hormone-free 1/2-MS medium. The highest percentage of shoot proliferation
was observed in embryogenic calluses in MS medium containing 2.0 μM BA and 1.0 μM NAA. In vitro-grown shoots were rooted in MS medium with 0.5–2.0 μM indole-3-butyric acid. Regenerants were transferred to vermiculite and
successfully established under an ex vitro environment in garden soil. 相似文献
19.
Embryogenic callus was obtained from bulb segments of Iris
pseudacorus on Murashige and Skoog (MS) medium with 2,4-dichlorophenoxyacetic acid (2,4-D) alone or in combination with kinetin. When
early globular somatic embryos were subcultured onto MS medium with 4.52 μM 2,4-D, high frequency of somatic embryogenesis
was obtained. Deprivation of 2,4-D was required for maturation. Mature somatic embryos had an elongated scutellum with a notch
on the base of scutellum. Separation of embryos from embryo clusters was necessary to enhance the frequency of germination.
Germination was stimulated by separation of embryos from embryo clusters and transfer onto fresh half-strength MS medium with
3% sucrose. After acclimation in artificial soil in greenhouse for 2 months, 96.4% of plantlets survived. 相似文献
20.
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