共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary Establishment of fast-growing, highly regenerable callus cultures was examined in Muscari armeniacum Leichtl. ex Bak. in order to develop an efficient genetic transformation system. High-frequency callus formation was obtained
from leaf explants of cv. Blue Pearl on media containing 2,4-dichlorophenoxyacetic acid (2,4-D), α-naphthaleneacetic acid
(NAA) or 4-amino-3,5,6-trichloropicolinic acid (picloram, PIC). Fast-growing, yellowish nodular callus lines and white friable
callus lines containing a few somatic embryos were established on initiation medium supplemented with 4.5 μM 2,4-D and with 54 μM NAA, respectively. The yellowish nodular calluses vigorously produced shoot buds after transfer to media containing 0.44–44
μM 6-benzyladenine (BA), whereas the white friable calluses produced numerous somatic embryos upon transfer to plant growth
regulator-free (PGR-F) medium. Histological observation of shoot buds and somatic embryos indicated that the former consisted
of an apparent shoot meristem and several leaf primordia, and the latter had two distinct meristematic regions, corresponding
to shoot and root meristems. Both shoot buds and somatic embryos developed into complete plantlets on PGR-F medium. Regenerated
plants showed no observable morphological alterations. High proliferation and regeneration ability of these calluses, were
maintained for over 2 yr. 相似文献
2.
Responses of Peanut Somatic Embryos to Thidiazuron 总被引:1,自引:0,他引:1
Induction of both somatic embryogenesis and organogenesis in presence of thidiazuron is reported in peanut tissues. However
the histological evidence of thidiazuron induced somatic embryogenesis was unclear. Thidiazuron triggered multiple shoot differentiation
in the plumule of the embryos. Keeping in view the ability of thidiazuron to induce both organogenesis and embryogenesis in
peanut tissues, experiments were conducted to define the pathway of morphogenesis in the plumule of rooted somatic embryos.
On exposure to thidiazuron, projections appeared from the plumule. These projections closely resemble the somatic embryos.
However histological examination revealed that these are caulogenic buds and not somatic embryos. In concurrence with the
earlier reports on thidiazuron induced organogenesis it is concluded that this growth regulator induces organogenic response
in peanut tissues.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Anwaar Ahmad Heng Zhong Wengling Wang Mariam B. Sticklen 《In vitro cellular & developmental biology. Plant》2002,38(2):163-167
Summary We report a less genotype-dependent in vitro regeneration system capable of producing multiple shoot clumps and whole plants in four different wheat genotypes. Shool
apical meristems from 7-d-old-seedlings produced axillary and adventitious shoots and somatic embryos on media containing
N6-benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid (2,4-D). All four genotypes responded positively to shoot multiplication
depending upon media composition. Scanning electron microscopies of cultures showed a proliferating budding state that gave
rise to adventitious shoots and somatic embryos on further multiplication. The percentage of relative shoot apical meristem
multiplication was 80–90%, and the average number of shoot meristems per multiplied shoot was 40–50 in all genotypes. Among
different concentrations of phytohormones, 2 and 4 mgl−1 BA (8.8 and 17.7 μM) in combination with 0.5 mg l−1 2,4-D (2.26 μM) gave the best results. Actively multiplying shoot clumps were recovered with high frequency among 3-mo.-old cultures. These
shoot clumps regenerated normally and produced fertile plants containing viable seeds. This in vitro system might prove useful for the production of transgenic plants of wheat in a relatively genotype-independent manner. 相似文献
4.
Summary Three auxin-type herbicides, namely 2.4-dichlorophenoxyacetic acid (2,4-D), (4-chlorophenoxy)acetic acid 2-(dimethylamino)ethyl
ester (centrophenoxine), and quinolinecarboxylic acid (quinclorac) induced direct somatic embryogenesis in seed-derived zygotic
embryo explants of sweet pepper (Capsicum annuum L.) when added to Murashige and Skoog medium with 200 mM sucrose. Optimum concentrations for embryogenesis induction were 0.40–0.45 mM and 1.15–1.30 μM for 2.4-D and centrophenoxine, respectively (in the presence of 5.0 gl−1 activated charcoal), or 40 μM for quinclorac (in medium without activated charcoal). Somatic embryos emerged from the epidermal and subepidermal tissues
and developed on the surface of the explant. Centrophenoxine- or 2.4-D-mediated embryogenesis was accomplished from 95% of
the explants in about 3 wk and, on average, six embryos were formed per explant. Induction efficieney was lower for quinelorac.
Centrophenoxine-mediated embryognesis was possible in 10 pepper cultivars, the extent of the reponse-being genotype-dependent.
embryos detached from the explant and transplanted onto a growth regulator-free medium germinated; however, the recovered
regenerants were without a shoot, and some of them bore a single deformed cotyledon while others had no cotyledons. Regenerants
lacking a shoot were generated irrespective of the auxin type applied and across all responsive genotypes investigated. Absence
of a shoot, resulting from a failure in the establishment of a normal functioning apical shoot meristem, was the principal
developmental disorder that precluded regeneration of normal plants via direct somatic embryogenesis. Since stem cells of
the shoot meristem become established in globular and heart-stage embryos, we deduce that the absence of a shoot in germinating
embryos could orginate from deviant differentiation at these early stages of embryogeny. 相似文献
5.
Somatic embryos were obtained from immature zygotic embryos of Cedrela fissilis Well. (Meliaceae), after a culture period of 12 months, with regular subcultures every 6–8 weeks. Callus was developed on explants in 2 months
on Murashige and Skoog (MS) medium containing 2,4 dichlorophenoxyacetic acid (2,4-D) or picloram (PIC). When the calli were
transferred to fresh medium, embryogenic tissue appeared on MS + 45 μM 2,4-D, or 22.5 μM 2,4-D + 0.4 μM 6-benzyladenine (BA),
or 20.7 μM PIC after 6 months. Sub-culture of embryogenic tissue in MS medium supplemented with 4.5 μM 2,4-D resulted in the
differentiation into somatic embryos after further 4 months. Repeated secondary somatic embryogenesis was achieved by regular
subculture on this medium. Maturation and conversion of somatic embryos into plantlets was achieved on MS medium without plant
growth regulators and the conversion frequency was approximately 12.5 %. The plantlets were successfully acclimatized in pots
with soil. Histological studies showed that somatic embryos had no detectable connection with the mother explants and that
somatic embryos in advanced stages were bipolar with shoot and root apical meristems, they contained vascular system and showed
typical characteristics of a somatic dicotyledonous embryo. 相似文献
6.
In vitro morphogenesis of Cucumis melo var. inodorus 总被引:2,自引:0,他引:2
Liborio Stipp Liliane C. Januzzi Mendes Beatriz M. Stefano Piedade Sonia M. D. Martinelli Rodriguez Adriana P. 《Plant Cell, Tissue and Organ Culture》2001,65(1):81-89
In vitro morphogenesis of C. melo L. var. inodorus was studied by the induction of adventitious buds and somatic embryos. Organogenesis was obtained from cotyledon segments
and leaf discs in culture medium supplemented with benzylaminopurine (1 mg l−1) and somatic embryogenesis was induced in medium containing 2,4-dichlorophenoxyacetic acid (5 mg l−1) + thidiazuron (1 mg l−1). Through histological analysis it was possible to verify that in cotyledonary explants, protuberances that do not develop
into well-formed shoot buds and leaf primordia are more frequently formed than complete shoot buds, resulting in a low frequency
of plant recovery in the organogenic process. A high percentage of explants responded with the formation of somatic embryos;
the microscopical analysis showed that the somatic embryos lacking well developed apical meristems had a low conversion rate
into plants. Plant recovery was not obtained from leaf-disc explants, with high rates of contamination and formation of protuberances
which did not develop into shoot buds. Histological sections showed the development of epidermis and leaf hairs, indicating
those structures could be leaf primordia; however, these were not associated with a shoot apical meristem.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Kanniah Rajasekaran John W. Pellow 《In vitro cellular & developmental biology. Plant》1997,33(2):88-91
Summary Regeneration of several varieties of soybean [Glycine max (L.) Merrill] by somatic embryogenesis from cultured epicotyls and primary leaves has been demonstrated. Somatic embryogenesis
was induced from epicotyls and primary leaves when cotyledon halves with the intact zygotic embryo axes were cultured on Murashige
and Skoog (MS) medium supplemented with 10 mg 1−1 (45.2 μM) 2,4-D. Stable, continuously proliferating globular embryo cultures (GEC) were established from small groups of somatic embryos
on MS medium supplemented with 20 mg 1−1 (90.5 μM) 2,4-dichlorophenoxyacetic acid (2,4-D). Rapid multiplication of shoot tips from germinating somatic embryos was achieved
on Cheng’s basal medium (CBO) containing 2.5 mg 1−1 (11.3 μM) 6-benzyladenine. Fertile plants were obtained from individual somatic embryos and in vitro propagated adventitious shoot bud cultures. 相似文献
8.
R. V. Sairam C. Wilber J. Franklin B. Smith J. Bazil R. Hassel D. Whaling K. Frutiger C. A. Blakey R. Vierling S. L. Goldman 《In vitro cellular & developmental biology. Plant》2002,38(5):435-440
Summary A protocol for high-frequency callus, somatic embryogenesis, and plant regeneration for Tripsacum is described. Plants were regenerated from complete shoot meristems (3–4 mm) via organogenesis and embryogenesis. In organogenesis,
the shoot meristems were cultured directly on a high cytokinin medium comprising 5–10 mgl−1 (22.2–44.4 μM) 6-benzyladenine (BA). The number of multiple shoots varied from six to eight from each meristem. The time required for production
of plants from organogenesis was rapid (4–6 wk). In contrast, callus was induced on an auxin medium and continuously cultured
on an auxin medium for production of somatic embryos. Prolific callus with numerous somatic embryos developed within 3–4 wk
when cultured on an auxin medium containing 5 mgl−1 (22.6μM), 2,4-dichlorophenoxyacetic acid (2,4-D). The number of shoots induced varied from two to five per callus. Regardless of
the cultivars used, the frequency of callus induction and plant regeneration was between 48% and 94%. The seed germination
procedures also were modified and resulted in a maximum of 60–80% seed germination. Finally, the rate of T-DNA transfer to
complete shoot meristems of Tripsacum was high on the auxin medium and was independent of whether super-virulent strains of Agrobacterium were used or not. 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.
Effect of TDZ and 2, 4-D on peanut somatic embryogenesis and in vitro bud development 总被引:2,自引:0,他引:2
Failure of peanut somatic embryos to convert into plantlets is attributed to the abnormal development of the plumule. Thidiazuron
(TDZ) was effective in the conversion of peanut somatic embryos to plantlets by triggering morphogenetic activity in the abnormal
plumules of the rooted somatic embryos. The present study aimed to induce normal embryo differentiation by culturing the embryogenic
masses in embryo development medium containing 2,4-D and various concentrations of TDZ. Although this was not achieved due
to restricted somatic embryo development in the presence of TDZ, bud-like projections appeared in the embryogenic masses when
these were cultured in media containing combinations of 2,4-D and TDZ. These projections developed into buds, which subsequently
formed shoots and plantlets. The response varied with the concentration and exposure of TDZ. At lower concentrations, the
buds appeared in a defined row in the equatorial region of the explant, and with extended incubation, more and more buds appeared
in rows alongside the initial row. Induction of multiple buds in a defined row in this specific site (equatorial region) suggested
the presence of potent cells around this region. At higher concentrations, these projections appeared in large numbers spread
over the whole upper part of the embryogenic mass starting from the equatorial region. The ability of embryogenic mass to
convert into organogenic mass and to produce large number of organogenic buds provides an excellent system for basic studies
and for the genetic transformation of peanut. 相似文献
11.
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
12.
Thomas L. Reynolds 《American journal of botany》1989,76(4):609-613
The development of adventitious shoot formation from cultured somatic tissues of Solanum carolinense was studied using light microscopy. For purposes of comparison, callus initiation and proliferation were also followed. When stem segments of this plant were cultured on medium supplemented with 6 mg/l benzyladenine (BA), cell division was first observed after 48 hr in the external phloem and inner cortex of the segments. This division activity gave rise to meristematic zones which subsequently formed shoot primordia within 6 days of culture. While organogenic potential appears to be limited to specific regions, all tissues of the explant were capable of callus formation when cultured on medium containing 3 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D). In conjunction with a previous study, it appears that unlike somatic embryogenesis in this species, organogenesis does not require an intermediate callus phase for differentiation to occur. 相似文献
13.
Somatic embryos developed directly from 96 and 110 day post-anthesis Cercis canadensis L. (redbud) zygotic embryos from one of two trees sampled that were explanted onto modified Schenk and Hildebrandt medium amended with either 1, 2, 3 or 5 mg/1 2,4-D in combination with either 7.6 or 12. 6 mM ammonium ion. Although somatic embryogenesis was expressed on most media, the number of explants that produced somatic embryos and the mean number of embryos formed per explant were greatest on media that contained either 2 or 3 mg/1 2,4-D; 12.6 mM ammonium ion inhibited embryogenesis from 96 day post-anthesis explants. Zygotic embryos explanted 117 days after anthesis produced only callus and roots. Somatic embryos that were bottle-shaped or had distinct cotyledons organized roots on germination media, but only one embryo formed a shoot. No additional development occurred. Histological examination of somatic embryos showed that shoot apical meristems were poorly developed.Abbreviations 2,4-D
2, 4-dichlorophenoxyacetic acid
- NAA
1-naphthaleneacetic acid
- BAP
6-benzylaminopurine
- FPA
Formalin-propionic acid-ethanol (50%) 相似文献
14.
Ana Cristina Gomes da Cunha Manuel Fernandes Ferreira 《Plant Cell, Tissue and Organ Culture》1996,47(1):1-8
The effects of plant growth regulators (PGR) on calli induction, morphogenesis and somatic embryogenesis of flax were studied. The organogenic and callus formation capacity were assessed for different types of source explants. Root and shoot explants were equally good material for calli production but the former produced calli without shoot regeneration capacity. Under the experimental conditions tested, 2,4-dichlorophenoxyacetic acid (2,4-D) + zeatin was the most efficient PGR combination on calli induction and biomass production. The calli were green but with no rhizogenic capacity. In contrast, and at similar concentrations, indole-3-butyric acid (IBA) + kinetin induced white or pale green friable calli with a good root regeneration capacity (60%). A factorial experiment with different combinations of 2,4-D + zeatin + gibberellic acid (GA3) levels revealed that the direction of explant differentiation was determined by specific PGR interactions and concentrations. The results from these experiments revealed that the morphogenetic pathway (shoot versus root differentiation) can be manipulated on flax explants by raising the 2,4-D level from 0.05 to 3.2 mg l?1 in the induction medium. The induction and development of somatic embryos from flax explants was possible in a range of 2,4-D + zeatin concentrations surrounding 0.4 mg l?1 2,4-D and 1.6 mg l?1 zeatin, the most efficient growth regulator combination. 相似文献
15.
A. V. Raghu Kuzhiyumparambil Unnikrishnan S. P. Geetha Gerald Martin Indira Balachandran 《In vitro cellular & developmental biology. Plant》2011,47(4):506-515
Embelia ribes, an important vulnerable medicinal liana, was regenerated through organogenesis and embryogenesis using leaf explants. Leaf
explants produced organogenic calluses on MS medium supplemented with 1.0 mg l−1 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5 mg l−1 6-benzylaminopurine. Shoot regeneration was obtained from organogenic calluses on MS medium containing different concentrations
of thidiazuron (TDZ) and indole-3-acetic acid (IAA). The frequency of shoot bud organogenesis was highest (23.9 shoots/explant)
in MS medium containing 0.5 mg l−1 TDZ and 0.1 mg l−1 IAA. The best result for induction of embryogenic callus was noticed in the combination of 2.0 mg l−1 TDZ and 0.5 mg l−1 2,4-D. This callus, maintained in the same medium, showed the highest differentiation of embryos (56.5%) after 6 wk of culture.
Embryos were transferred to MS medium supplemented with different concentrations of TDZ, and this facilitated conversion of
embryos into plants. After 6 wk of subculture, MS medium with 0.05 mg l−1 TDZ favored the highest percentage (52.2%) embryo conversion. As per the present protocol, 52.2% of the embryos underwent
conversion, and a mean number of 29.5 shoots per culture was obtained. Shoots developed from both types of calluses were rooted
on half-strength MS basal medium supplemented with 1.0 mg l−1 indole-3-butyric acid. HPLC-UV assay demonstrated the highest embelin content (5.33% w/w) in the embryogenic callus cultures. Embelin was isolated from embryogenic callus and was identified using IR and 1H NMR studies. 相似文献
16.
Maize shoot apices (1 to 2mm size) from two sources were used to recover normal plantlets. The first explant source included shoot apices from the embryonic axis of immature embryos, 12–14 days post pollination in the glasshouse (spring) or 15–20 days post pollination in the summer nursery. In most explants, the shoot apical meristem was surrounded by a coleoptile primordium which was removed before culture. The second explant source included shoot apices from the plumules of 72 h imbibed mature kernels. The coleoptile and all other leaf layers (leaf-1 to leaf-3 or 4) of the plumule were removed before culture to expose the apical meristem. Among the genotypes studied, a recovery of 43% (Mo17) to 100% (Oh43) of plantlets was achieved from shoot apices from immature embryo plumules cultured in MS medium. Recovery of 80% of Oh43 plantlets in MS medium and 40% of A188 plantlets from apices of plumules of imbibed (72 h) seeds in MS medium containing 2,4-dichlorophenoxyacetic acid was recorded. The plantlets derived from both explant sources grew normally and produced viable seeds upon pollination. 相似文献
17.
Callusing, caulogenesis, in vitro flowering and somatic embryogenesis were induced from the base of leaflets derived from mature embryos of peanut (Arachis hypogaea) by altering the hormonal composition of the Murashige and Skoog's (MS) basal medium. A combination of 4 mg/l alpha napththaleneacetic acid (NAA) and 5 mg/l 6-benylaminopurine (BAP) was optimum for inducing caulogenic buds. The caulogenic buds proliferated in medium with 3 mg/l BAP. Differentiation of these buds to shoots was achieved in MS basal medium with 0.5 mg/l each of BAP and kinetin (KN). Shoot buds and flower buds were produced when caulogenic buds were cultured on medium containing 1 mg/l BAP and 1 mg/l KN, prior to elongation. Clonally propagated plantlets derived from axillary buds elongated, formed roots and were grown to maturity in soil. Embryogenic mass formation was induced from the leaf base in the presence of 20 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D). Somatic embryos developed upon reducing 2,4-D to 3 mg/l. 相似文献
18.
Murugan Loganathan Subbiyan Maruthasalam Ling Yin Shiu Wei Ching Lien Wen Hwei Hsu Pei Fang Lee Chih Wen Yu Chin Ho Lin 《In vitro cellular & developmental biology. Plant》2010,46(3):265-273
We describe here a simple and efficient system of soybean (Glycine max L. Merrill) regeneration through direct somatic embryogenesis by using immature embryonic shoot tips (IEST) as explants.
The cultivar Kaohsiung 10 (cv. K10) used in this study did not show embryogenic response either from mature seed-derived explants
(cotyledon, embryonic tip, leaf, shoot and root) or immature cotyledons. However, it showed a high percentage (55.8%) of somatic
embryo (SEm) formation from the IEST excised 2–3 wk after flowering, thus indicating the crucial roles of type and age of
explants. The IEST put forth primary SEm after 2 mo of culturing on Murashige and Skoog (MS) medium supplemented with 6% sucrose,
164.8 μM 2,4-dichlorophenoxyacetic acid (2,4-D), 5 mM asparagine and 684 μM glutamine. Subsequently, secondary SEm were developed
1 mo after culturing on MS medium containing 123.6 μM 2,4-D and 3% sucrose. Cotyledonary embryos were induced on MS medium
supplemented with 0.5% activated charcoal after 1 mo. The embryos were desiccated for 72–96 h on sterile Petri dishes and
regenerated on hormone-free MS medium. Plantlets with well-developed shoots and roots were obtained within 5–6 mo of culturing
of IEST. The SEm-derived plants were morphologically normal and fertile. Various parameters thought to be responsible for
efficient regeneration of soybean through somatic embryogenesis are discussed. To our knowledge, this is the first report
to employ IEST as explants for successful direct somatic embryogenesis in soybean. 相似文献
19.
E. Sofiari C.J.J.M. Raemakers E. Kanju K. Danso A.M. van Lammeren E. Jacobsen R.G.F. Visser 《Plant Cell, Tissue and Organ Culture》1997,50(1):45-56
NAA and 2,4-D were compared for their ability to induce somatic embryogenesis in cassava (Manihot esculenta Crantz). In all seven cultivars tested, only 2,4-D had the capacity to induce primary somatic embryos from leaf explants,
however, both NAA and 2,4-D were capable of inducing secondary somatic embryos. More secondary somatic embryos were formed
in NAA than in 2,4-D medium. Furthermore, the maturation period for secondary somatic embryos was shorter in NAA medium than
in 2,4-D medium. In some cultivars, repeated subculture of secondary somatic embryos in NAA medium resulted in a gradual shift
from somatic embryogenesis to adventitious root formation. This shift could be stopped and reversed by subculture of the material
in 2,4-D medium. In NAA medium the most secondary somatic embryos were formed when they were subcultured every 15 days whereas
in 2,4-D a 20 day subculture interval was optimal. Subculture of secondary somatic embryos at a high inoculum density (>1.5
g jar−1) in NAA medium did not result in the formation of secondary somatic embryos, whereas in 2,4-D it lead to the formation of
globular secondary somatic embryos. With 2,4-D the newly induced secondary somatic embryos were connected vertically to the
explant and with NAA medium horizontally. For all cultivars tested, desiccation stimulated normal germination of NAA-induced
somatic embryos. However, the desiccated, secondary somatic embryos required a medium supplemented with BA for high frequency
germination. The concentration of BA needed for high frequency germination was higher when the desiccated secondary somatic
embryos were cultured in light instead of dark. In only one cultivar desiccation enhanced germination of 2,4-D induced secondary
somatic embryos and in three other cultivars it stimulated only root formation.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
Jean-Luc Verdeil Christine Huet Frédérique Grosdemange Jacqueline Buffard-Morel 《Plant cell reports》1994,13(3-4):218-221
Immature inflorescences of coconut belonging to three different genotypes were cultured on a solid medium supplemented with activated charcoal (2%) and a range of 2,4-dichlorophenoxyacetic acid (2,4-D) concentrations (from 1.5 to 3.5 × 10–4M). Globular white callus formed from immature floral meristems, depending on inflorescence age and 2,4-D concentration. Acquisition of embryogenic competence is described histologically. Somatic embryos presented a functional bipolar organization with a completely differentiated shoot meristem which is reported here for the first time in coconut tissue culture. Embryo maturation allowed reliable plant regeneration of this in vitro recalcitrant species. Details are given of exogenous hormonal requirements for the acquisition of embryogenic competence and embryo maturation. 相似文献