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1.
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
2.
P. I. P. Perera D. M. D. Yakandawala V. Hocher J-L. Verdeil L. K. Weerakoon 《Plant Cell, Tissue and Organ Culture》2009,96(2):171-180
The effect of growth regulators on induction of androgenesis in coconut was investigated using seven different growth regulators
at various concentrations and combinations. Three auxins (1-naphthalene acetic acid—NAA, indoleacetic acid—IAA, picloram)
and three cytokinins (2-isopentyl adenine-2-iP, kinetin, zeatin) were tested either alone or in combination with 2,4-dichlorophenoxyacetic
acid (2,4-D), using modified Eeuwens Y3 liquid medium as the basal medium. Among the tested auxins, 100 μM NAA in combination
with 100 μM 2,4-D enhanced the production of calli/embryos (123) whereas IAA and picloram showed negative and detrimental
effects, respectively, for androgenesis induction over 100 μM 2,4-D alone. Kinetin and 2-iP enhanced the production of calli/embryos
when 100 μM 2,4-D was present in the culture medium. Both cytokinins at 10 μM yielded the highest frequencies of embryos (113
and 93, respectively) whereas zeatin (1 or 2.5 μM) had no impact on microspore embryogenesis. When calli/embryos (produced
from different treatments in different experiments) were sub-cultured in somatic embryo induction medium (Y3 medium containing 66 μM 2,4-D), followed by maturation medium (Y3 medium without growth regulators) and germination medium (Y3 medium containing 5 μM-6-benzyladenine—BA and 0.35 μM gibberellic acid—GA3), plantlets were regenerated at low frequencies (in most treatments ranging from 0% to 7%). 相似文献
3.
T. H. Lan P. I. Hong C. C. Huang W. C. Chang C. S. Lin 《In vitro cellular & developmental biology. Plant》2009,45(1):44-47
Whole plants were regenerated from excised leaves of Drimiopsis kirkii Baker (Lily of the Valley) through direct somatic embryogenesis. An initial exposure to a low level of 2,4-dichlorophenoxyacetic
acid (2,4-D, 0.45 μM) in the medium was essential in inducing the direct formation of somatic embryos. A high concentration
of 2,4-D (4.52 μM) in the proliferation medium reduced embryogenesis and enhanced callus formation. The presence of kinetin
in the medium enhanced the somatic-embryogenesis-inducing effect of 2,4-D (0.45 μM). The maximum embryogenesis rate (4,026
somatic embryos per gram of leaf) was obtained in explants cultured for 30 d in medium supplemented with 2.33 μM kinetin and
0.45 μM 2,4-D (embryo induction medium). Kinetin (4.65 μM) also enhanced embryo germination (97.6%), but the presence of α-naphthalene
acetic acid in the medium drastically reduced embryo germination. Following conversion, the regenerated plantlets were transferred
to soil and showed normal morphological characteristics. 相似文献
4.
S. Zdravković-Korać J. Milojević Lj. Tubić D. Ćalić-Dragosavac N. Mitić B. Vinterhalter 《Plant Cell, Tissue and Organ Culture》2010,101(2):237-244
A protocol has been developed for somatic embryogenesis and subsequent plant regeneration in Allium schoenoprasum L. Calli were induced from root sections isolated from axenic seedlings and cultivated on media containing either Murashige
and Skoog’s (MS) or Dunstan and Short’s mineral solution supplemented with 5 μM 2,4-dichlorophenoxyacetic acid (2,4-D) in
combination with 6-benzylaminopurine (BA), 6-furfurylaminopurine (Kin) or thidiazuron (TDZ) at 1, 5 or 10 μM. The highest
frequencies of callus induction were achieved on media with 5 μM 2,4-D in combination with 5 μM TDZ or 10 μM BA (78.9% and
78.4%, respectively). Calli were then transferred to 1 μM 2,4-D, where compact yellow callus turned to segmented yellowish
callus with transparent globular somatic embryos at the surface. Calli that were previously grown on media with 5 μM 2,4-D
in combination with 10 μM BA or 10 μM TDZ showed the highest frequencies of embryogenic callus formation (45% and 42%) as
well as mean number of somatic embryos per regenerating callus. The choice of mineral solution formulation did not significantly
affect callus induction or embryogenic callus formation. The embryos could complete development into whole plants on plant
growth regulator (PGR)-free medium, but inclusion of Kin (0.5, 2.5 and 5 μM) in this phase improved somatic embryo development
and multiplication. Subsequently transferred to 1/2 MS PGR-free medium, all embryos rooted and the survival rate of the plants
in a greenhouse was 96%. 相似文献
5.
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
6.
A simple and efficient system was developed for rapid somatic embryogenesis from leaf explants of Merwilla plumbea, a traditional but threatened medicinal plant in South Africa. Friable embryogenic callus (FEC) was obtained from leaf explants
on embryogenic callus induction medium containing agar-solidified Murashige and Skoog (MS) salts and vitamins, 8.3 μM picloram,
2.3 μM thidiazuron (TDZ) and 20 μM glutamine. FEC was subsequently incubated in embryogenic callus proliferation medium containing
4.5 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.1 μM picloram for 7 days before it was transferred to liquid somatic embryo
medium (SEML) containing MS medium supplemented with 0.4 μM picloram and 0.9 μM TDZ. In SEML supplemented with 150 mg L−1 haemoglobin, 5.4–35.6 somatic embryos per settled cell volume of 500 mg FEC were obtained. These embryos were at globular
to cotyledonary developmental stages. Embryo maturation, germination and plant formation rate was 94.4% following transfer
of SEs to half-strength MS medium supplemented with 1.4 μM gibberellic acid. Plantlets transferred into soil acclimatized
in the misthouse and established successfully in the greenhouse (100%). This is the first report on induction of Merwilla plumbea somatic embryogenesis. The protocol developed offers controlled vegetative propagation by alleviating extinction threats,
ensures germplasm conservation and provides a system for physiological, biochemical, molecular and cellular studies of embryo
development. 相似文献
7.
Perera PI Hocher V Verdeil JL Doulbeau S Yakandawala DM Weerakoon LK 《Plant cell reports》2007,26(1):21-28
Unfertilized ovaries isolated from immature female flowers of coconut (Cocos nucifera L.) were tested as a source of explants for callogenesis and somatic embryogenesis. The correct developmental stage of ovary explants and suitable in vitro culture conditions for consistent callus production were identified. The concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) and activated charcoal was found to be critical for callogenesis. When cultured in a medium containing 100 μM 2,4-D and 0.1% activated charcoal, ovary explants gave rise to 41% callusing. Embryogenic calli were sub-cultured into somatic embryogenesis induction medium containing 5 μM abscisic acid, followed by plant regeneration medium (with 5 μM 6-benzylaminopurine). Many of the somatic embryos formed were complete with shoot and root poles and upon germination they gave rise to normal shoots. However, some abnormal developments were also observed. Flow cytometric analysis revealed that all the calli tested were diploid. Through histological studies, it was possible to study the sequence of the events that take place during somatic embryogenesis including orientation, polarization and elongation of the embryos. 相似文献
8.
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
9.
P. Jha C. B. Yadav V. Anjaiah V. Bhat 《In vitro cellular & developmental biology. Plant》2009,45(2):145-154
An efficient in vitro plant regeneration protocol through somatic embryogenesis and direct shoot organogenesis has been developed for pearl millet
(Pennisetum glaucum). Efficient plant regeneration is a prerequisite for a complete genetic transformation protocol. Shoot tips, immature inflorescences,
and seeds of two genotypes (843B and 7042-DMR) of pearl millet formed callus when cultured on Murashige and Skoog (MS) medium
supplemented with varying levels of 2,4-dichlorophenoxyacetic acid (2,4-D; 4.5, 9, 13.5, and 18 μM). The level of 2,4-D, the
type of explant, and the genotype significantly effected callus induction. Calli from each of the three explant types developed
somatic embryos on MS medium containing 2.22 μM 6-benzyladenine (BA) and either 1.13, 2.25, or 4.5 μM of 2,4-D. Somatic embryos
developed from all three explants and generated shoots on MS medium containing high levels of BA (4.4, 8.8, or 13.2 μM) combined
with 0.56 μM 2,4-D. The calli from the immature inflorescences exhibited the highest percentage of somatic embryogenesis and
shoot regeneration. Moreover, these calli yielded the maximum number of differentiated shoots per callus. An efficient and
direct shoot organogenesis protocol, without a visible, intervening callus stage, was successfully developed from shoot tip
explants of both genotypes of pearl millet. Multiple shoots were induced on MS medium containing either BA or kinetin (4.4,
8.8, 17.6, or 26.4 μM). The number of shoots formed per shoot tip was significantly influenced by the level of cytokinin (BA/kinetin)
and genotype. Maximum rooting was induced in 1/2 strength MS with 0.8% activated charcoal. The regenerated plants were transferred
to soil in pots, where they exhibited normal growth. 相似文献
10.
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
11.
Nasser J. Y. Sholi Anjana Chaurasia Anuradha Agrawal Neera Bhalla Sarin 《Plant Cell, Tissue and Organ Culture》2009,99(2):133-140
Creamy friable calli were induced from meristems (scalps) of proliferating shoots of plantain (Musa sp.) cv. Spambia (genome AAB) incubated on a semi-solid modified Murashige and Skoog (MS) medium supplemented with 4.5 μM
2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 μM zeatin. About 25% of shoot-tip explants formed scalps, and about 98% of
scalps developed embryogenic calli. Small dense aggregates of cells, were obtained when these calli were transferred to liquid
MS medium supplemented with 4.5 μM 2,4-D and 1.0 μM zeatin. Upon transfer to semi-solid MS medium of the same composition
as described above, aggregates of cells formed somatic embryos. In the presence of 2.5 μM abscisic acid (ABA), maturation
of somatic embryos was 2.6-fold higher than that of control (lacking ABA), and regardless of the type of cytokinin used in
the medium. Upon transfer to MS medium supplemented with 1.25 μM 6-benzyladenine (BA), 80% of germinated embryos developed
into plantlets. 相似文献
12.
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
13.
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
14.
Qin-Mei Wang Feng-Zhan Gao Xiang Gao Fan-Yu Zou Xin Sui Meng Wang Yue-Jun Hui Li Wang 《Plant Cell, Tissue and Organ Culture》2012,109(2):191-200
An efficient in vitro micropropagation system for Clivia miniata Regel was developed using basal tissues of young petals and young ovaries as explants. For callus induction, explants were
incubated on Murashige and Skoog (MS) medium containing either 2.22 μM 6-benzyladenine (BA) and 4.52 μM 2,4-dichlorophenoxyacetic
acid (2,4-D) or 4.44 μM BA, 5.37 μM α-naphthaleneacetic acid (NAA), and 9.05 μM 2,4-D. Moreover, callus was induced from young
ovaries when these were incubated on MS medium containing 8.88 μM BA, 10.74 μM NAA, and 9.05 or 18.10 μM 2,4-D. Subsequently,
callus was transferred to MS medium supplemented with kinetin (KT) and NAA for shoot organogenesis. Frequency of shoot regeneration
from petal-derived callus was highest when callus was transferred to medium containing 2.69 μM NAA with either 9.29 or 13.94 μM
KT. Shoot regeneration frequency from ovary-derived callus was highest when this callus was transferred to medium containing
9.29 μM KT and 10.74 μM NAA. Overall, different explant types exhibited different organogenic capacities wherein, young petals
had higher shoot regeneration frequencies than young ovaries. The highest rooting frequency (98.25 ± 3.04%) was obtained when
shoots were transferred to half-strength MS medium without plant growth regulators. Regenerated plantlets were transplanted
to soil mix and acclimatized, yielding a 96.80% survival frequency. Only 0.6% of regenerated plantlets exhibited morphological
changes. The diploid status (2n = 22) of regenerated plantlets was determined using chromosome counts of root-tips. Moreover, inter-simple sequence repeats
were used to assess the genetic fidelity of regenerated plantlets. Overall, regenerated plants shared 90.5–100.0% genetic
similarities with mother plants and 89.0–100.0% similarities with each other. 相似文献
15.
An efficient method of repetitive somatic embryogenesis and plant regeneration of two carnation cultivars (Sagres and Impulse)
was established using a two-step protocol. In the first step, embryogenic tissue were induced from petal explants on MS culture
medium containing 9% sucrose (w/v), 9 μM 2,4-D and 0.8 μM BA. In the second step, embryogenic tissue transferred onto the
MS medium containing 3% sucrose supplemented with different concentrations of picloram (0.8, 2, 4, 8 and 16 μM) to produce
primary somatic embryos. Precotyledonary clumps and cotyledonary somatic embryos were then isolated and subcultured onto the
same media as the second step where they formed secondary somatic embryos in repetitive cycles. Cotyledony somatic embryos
were converted into plantlets when they transferred onto the growth regulator-free half-strength MS medium followed by being
acclimated to the greenhouse conditions. 相似文献
16.
Suresh Chand Ashok Kumar Sahrawat 《In vitro cellular & developmental biology. Plant》2002,38(1):33-38
Summary An efficient plant regeneration protocol has been developed from root explants of Psoralea corylifolia L., an endangered medicinally
important herbaceous plant species belonging to the family Fabaceae. Nodular embryogenic callus was initiated from young root
segments cultured on Murashige and Skoog (MS) medium (1962) supplemented with α-naphthaleneacetic acid (NAA; 2.68–13.42 μM)
or 2,4-dichlorophenoxyacetic acid (2.4-D; 2.25–11.25 μM) in combination with 6-benzylaminopurine (BA: 2.2. μM). thiamine HCl
(2.9 μM), L-glutamine (342.23 μM) and sucrose (3.0% w/v). The highest frequency (95.2%) of embryogenic calluses was obtained on MS medium
supplemented with the growth regulators NAA (10.74 μM) and BA (2.2 μM). Development and maturation of somatic embryos was
achieved after transfer of embryogenic calluses to MS medium supplemented with 1.34 μM NAA or 1.12 μM 2,4-D and 4.4–13.2 μM
BA. The maximum number (13.8±1.34) of cotyledonary stage somatic embryos was obtained on MS medium containing 1.34 μM NAA
and 13.2 μM BA. Germination of somatic embryos occurred on MS medium without any growth regulators and also on MS medium enriched
with BA (1.1–8.8 μM), although the maximum germination frequency (76.1%) was obtained on 4.4 μM BA plus 1.45 μM gibberellic
acid (GA3). Plant regeneration without complete somatic embryo maturation was also achieved by transferring clumps of nodular embryogenic
calluses onto MSO medium or MS medium supplemented with NAA (1.34 μM) and BA (2.2–8.8 μM). The highest frequency of plant
regeneration (93.3%) and mean number of plantlets (15.4±0.88) were obtained on MS medium containing 1.34 μM NAA and 4.4 μM
BA. Regenerated plants with well-developed root systems were transferred to pots where they grew vigorously, attained maturity
and produced fertile seeds. 相似文献
17.
Efficient somatic embryogenesis (SE) and in vitro flowering and fruiting were achieved in Saposhnikovia divaricata (Turcz.) Schischk. Friable embryogenic callus developed from the root, internode, and leaf explants on Murashige and Skoog
medium (MS) with 2.26 μM 2,4-dichlorophenoxyacetic acid (2,4-D), and subsequently developed into somatic embryos on MS medium
containing 4–5% sucrose, 1.74 μM naphthaleneacetic acid (NAA), 4.44 μM 6-benzylaminopurine (BA), and 1.90 μM abscisic acid
(ABA). Then the mature embryos were separated and transferred onto MS with 3% sucrose and 0.6% agar for further development
and conversion to plantlets. In vitro flowering and fruiting were obtained when the subcultures were carried out for over
15 months. Paclobutrazol (PP333) or ethephon (ETH) at low levels promoted flowering significantly. Also, abnormal rootless
somatic embryos of S. divaricata could form flowers and fruits in vitro. 相似文献
18.
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
19.
Somatic embryos of myrtle (Myrtus communis L.) were induced from mature zygotic embryos cultured in MS medium supplemented
with several concentrations of 2,4-D (2.26 μM – 18.98 μM) or Picloram (2.07 μM – 16.5 μM) combined with 0.087 M or 0.23 M
sucrose. For all the concentrations of 2,4-D or Picloram tested, 0.087 M sucrose proved to be more effective than 0.23 M.
The best frequencies of induction were obtained in a medium containing 2.26 μM 2,4-D in which 97.3% of the explants produced
somatic embryos. Although most embryos were produced from the adaxial side of the cotyledons, some of them differentiated
from the hypocotyl. Secondary somatic embryos were often seen arising from the periphery of the former somatic embryos. Somatic
embryo development was not synchronous but practically all the embryos germinated well after being transferred to media containing
GA3 (0.29, 0.58 and 1.44 μM) alone. When benzyladenine was combined with gibberellic acid, germinating somatic embryos produced
adventitious shoot buds which contributed to an increase in plantlet regeneration. Histological observations suggested that
somatic embryos arise from the upper surface of the cotyledons probably from peripheral cells. Polyphenol-rich cells were
usually seen in association with meristematic-like cells from which somatic embryos originate or with earlier steps of somatic
embryo differentiation. Regenerated plants were phenotypically normal, showing a diploid (2n = 22) set of chromosomes.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
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