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1.
Zygotic embryos at different developmental stages were tested for their potential in the initiation of embryogenic suspensor
mass (ESM) lines using immature seeds of Pinus rigida × P. taeda. The highest frequency (1.1%) of ESM was obtained with explants from cones collected on July 1. All excised embryos of the
July 1 collection were at the early proembryo stage. Two different culture media were compared. Forty-eight ESM lines were
initiated on Pinus taeda basal medium (P6) (0.97%) with 13.5 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.4 μM benzyladenine (BA). However, only
four ESM were obtained on a modified Murashige and Skoog medium (MSG; 0.55%). Most of the ESM arose from the seeds that were
at the stages ranging from late cleavage polyembryony to the early staged proembryo. Out of 52 lines (0.46%) that were produced
from 11,388 explants, only two viable lines (0.018%) (PRT11 and PRT28) survived. As for somatic embryo maturation, the highest
number (224/g−1 FW) of matured cotyledonary somatic embryos (line PRT 28) was obtained on a medium containing 100 μM abscisic acid (ABA),
0.2 M maltose, and 1.2% gellan gum. For germination of the somatic embryos, the cotyledonary somatic embryos derived from
maturation medium were transferred on half-strength Litvay medium (LM) plus 0.4% gellan gum. The germination rates were high
(71.4–96.3%) regardless of the concentrations of either ABA or gellan gum in the maturation medium. Approximately 500 somatic
plants were recovered from the germination medium and transferred to the green house; finally most of them were transplanted
successfully to the experimental field. 相似文献
2.
Marie-Anne Lelu-Walter Michèle Bernier-Cardou Krystyna Klimaszewska 《Plant Cell, Tissue and Organ Culture》2008,92(1):31-45
Several factors affecting somatic embryogenesis (SE) in Pinus sylvestris from self- and cross-pollinated seed families were studied with the aim of producing large quantities of clonal plants. Somatic
embryogenesis initiation from zygotic embryos was improved on a medium with lower than standard concentrations of 2,4-dichlorophenoxyacetic
acid (2.2 vs. 9.5 μM) and 6-benzyladenine (2.2 vs. 4.5 μM). On this medium, initiation rates of four controlled crosses, including
one self-cross, varied from 3% to 25%. Among the maturation factors tested, the concentration of abscisic acid (ABA 80, 120 μM)
had no significant effect on the production of mature somatic embryos when the medium contained 0.1 M sucrose. When sucrose
concentration was 0.2 M, however, 1.4 times more mature somatic embryos were produced on medium with 80 μM compared with 120 μM
ABA. Under our best maturation conditions, mature somatic embryos accumulated amounts of storage proteins that were similar
to the amounts in mature zygotic embryos. Activated charcoal exerted a beneficial effect on mature somatic embryo production
of 24-week-old cultures; there was no evidence of such an effect in 8-week-old cultures. Thirty-seven embryogenic lines from
a self-cross and an out-cross were chosen for clonal plant production. Highly embryogenic lines produced mature somatic embryos
that were more likely to convert to plants than those from less embryogenic lines. After 4 months of growth in a shade house,
plantlet survival rates exceeded 70% for 31 lines out of 35. This report describes an improved method for accelerated production
of large quantities of Scots pine for clonal tests. 相似文献
3.
D. H. Tejavathi M. D. Rajanna R. Sowmya K. Gayathramma 《In vitro cellular & developmental biology. Plant》2007,43(5):423-428
Somatic embryogenesis from cultures of shoot apices, cotyledon and young leaves of in vitro shoots of Agave vera-cruz Mill. was studied. Embryogenic callus was obtained when explants were cultured on Murashige and Skoog’s (MS) medium (1962)
supplemented with L2 vitamins, 4.52 μM 2,4-dichlorophenoxyacetic acid (2,4-d) or 5.37 μM ∝-naphthalene acetic acid (NAA). Somatic embryos differentiated from this embryogenic callus upon subculture
to maturation/conversion medium containing cytokinin either alone or with auxin and l-glutamine. The best combination of growth regulators for development of somatic embryos was found to be 5.37 μM naphthalene
acetic acid plus 0.91 μM zeatin and 40 g/l sucrose. The conversion frequency of somatic embryos to plantlets varied from 46–50%.
Rooted plantlets were transferred directly to pots containing a soil, sand, and manure mixture without any hardening phase
with 96–98% survival of the plantlets. Based on the histological observations, the potential origin of the somatic embryo
is discussed. 相似文献
4.
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
5.
The initiation and development of somatic embryos and organogenic shoots and corm-like structures (CLSs) from petiole-derived
calli of Amorphophallus rivieri Durieu were observed histologically. The petioles were cultured on Murashige and Skoog (MS) medium supplemented with 5.37 μM
α-naphthaleneacetic acid (NAA) and 4.44 μM N6-benzylaminopurine (6-BA) for callus induction. The shoot and corm organogenesis occurred from the compact calli when they
were transferred to a medium containing 0.54 μM NAA and 4.44 μM 6-BA. A combination of 13.57 μM 2,4-dichlorophenoxyacetic
acid (2,4-D) and 8.88 μM 6-BA or 24.18 μM NAA and 6.66 μM 6-BA was optimum for induction of somatic embryos, which failed
to produce plantlets because of their structural abnormalities. Shoot regeneration predominantly happened through organogenesis
although somatic embryogenesis infrequently occurred. The subepidermal cells of the compact callus converted to competent
cells and started divisions, which resulted in formation of the meristemoids. The meristemoid cells continued division to
develop into bud primordia. Subepidermal cells could also form the globular structures. Subsequently, these globoids developed
into CLSs from which plantlets regenerated during subculture. Meanwhile, the CLSs were capable to form cormels, which could
be a promising way for the propagation of A. rivieri. 相似文献
6.
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
7.
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
8.
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
9.
E. Carneros C. Celestino K. Klimaszewska Y.-S. Park M. Toribio J. M. Bonga 《Plant Cell, Tissue and Organ Culture》2009,98(2):165-178
Regeneration of plants by somatic embryogenesis (SE) was achieved in Stone pine (Pinus pinea), one of the most characteristic tree species of the Mediterranean ecosystem. The initial explants were megagametophytes
containing zygotic embryos from five selected half-sib families collected at different dates over 2 consecutive years. Rates
of extrusion and initiation of SE differed in both years. However, qualitative patterns were very similar: for most families,
the responsive developmental window was from late cleavage polyembryony to early cotyledonary stage. The highest overall mean
frequencies of extrusion and SE initiation (7 and 0.9%, respectively, for the five families and the eight 2006 collections)
were obtained on a modified Litvay’s medium with 9 μM 2,4-D and 4.5 μM BAP, supplemented with L-glutamine and casein hydrolysate. Families showed large differences in frequencies of SE initiation from year to year. Only
seven embryogenic lines were induced in 2005, representing three of the five families tested, whereas 34 lines from all the
families were obtained in 2006. Proliferation of embryonal masses (EM) was significantly improved when they were subcultured
after dispersing in liquid medium and collected on filter paper disks, instead of being subcultured as small clumps. This
effect showed a significant interaction with genotype. Several preconditioning treatments and culture media combinations were
tested for embryo development and maturation. The high proliferation rate of EM hampered somatic embryo development. However,
up to 42 mature embryos from different lines of three of the five families were obtained, 23 of them germinated and seven
converted into somatic seedlings. 相似文献
10.
Somatic embryogenesis (SE) offers vast potential for the clonal propagation of high-value roses. However, some recalcitrant
cultivars unresponsive to commonly employed SE-inducing agents and low induction rates currently hinder the commercialization
of SE technology in rose. Rose SE technology requires improvement before it can be implemented as a production system on a
commercial scale. In the present work, we assessed 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a synthetic auxin not previously
tested in rose, for its effectiveness to induce SE in the rose cultivar ‘Livin’ Easy’ (Rosa sp.). We ran a parallel comparison to the commonly used 2,4-dichlorophenoxyacetic acid (2,4-D). We tested each auxin with
two different basal media: Murashige and Skoog (MS) basal medium and woody plant medium (WPM). MS medium resulted in somatic
embryo production, whereas WPM did not. 2,4,5-T induced SE over a greater concentration range than 2,4-D's and resulted in
significantly greater embryo yields. 2,4,5-T at a concentration of 10 or 25 μM was better for embrygenic tissue initiation
than 2,4,5-T at 5 μM. Further embryo development occurred when the tissue was transferred to plant growth regulator (PGR)
free medium or media with 40% the original auxin concentration. However, the PGR-free medium resulted in a high percentage
of abnormal embryos (32.31%) compared to the media containing auxins. Upon transfer to germination medium, somatic embryos
successfully converted into plantlets at rates ranging from 33.3 to 95.2%, depending on treatment. Survival rates 3 months
ex vitro averaged 14.0 and 55.6% for 2,4-D- and 2,4,5-T-derived plantlets, respectively. Recurrent SE was observed in 60.2%
of the plantlets growing on germination medium. This study is the first report of SE in the commercially valuable rose cultivar
‘Livin’ Easy’ (Rosa sp.) and a suitable methodology was developed for SE of this rose cultivar. 相似文献
11.
J. B. Kim C. J. J. M. Raemakers E. Jacobsen R. G. F. Visser 《Plant Cell, Tissue and Organ Culture》2006,86(2):233-238
In Alstroemeria high frequencies of compact embryogenic callus (CEC) induction (40%) and friable embryogenic callus (FEC) induction (15%) were obtained from nodes with axil tissue cultured first on a Murashige and Skoog (MS) medium supplemented with 10 μM thidiazuron and 0.5 μM indole-3-butyric acid and after that on a Schenk and Hildebrandt (SH) medium supplemented with 9.1 μM 2,4-dichlorophenoxy acetic acid and 2.2 μM benzylaminopurine (BA). Both types of callus were maintained on modified MS medium supplemented with 20.8 μM picloram. CEC and FEC formed somatic embryos and subsequently plants when transferred to MS medium supplemented with 2.2 μM BA. Plants were produced after 12 weeks (CEC) or after 16 weeks (FEC) of culture. Regenerated plants were established in the greenhouse and flowered normally. 相似文献
12.
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
13.
L. Buendía-González J. Orozco-Villafuerte F. Cruz-Sosa V. M. Chávez-Ávila E. J. Vernon-Carter 《In vitro cellular & developmental biology. Plant》2007,43(3):260-266
Plantlet regeneration in Prosopis laevigata (Humb. & Bonpl. ex Willd.) Johnston (Fabaceae), a multipurpose tree, has been achieved from cotyledonary nodes excised from
in vitro grown seedlings. The explants were cultured on MS media containing different concentrations of N-6 benzyladenine (BA) and
2,4-dichlorophenoxyacetic acid (2,4-d) and a mixture of organic components. The highest number (3.37 + 0.51) of multiple shoots was observed in MS media containing
2,4-d (9.05 μM) + BA (6.62 μM). The regenerated shoots were then transferred onto half-strength MS medium containing a plant growth
regulator that was either: indole-3-butyric acid, 1-naphthaleneacetic, indole-3-acetic acid, or 2,4-d as well as phytagel or vermiculite for adventitious root initiation. Best rooting efficiency of 44.0% was obtained when NAA
(16.11 μM) and vermiculite were used. After rooting, the cloned plantlets were successfully hardened to ex vitro conditions. This work may help to reduce the devastation caused by the overexploitation of this species. 相似文献
14.
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
15.
Organogenic cultures were induced from zygotic embryo and megagametophyte explants of the Central American cycad species,
Dioon edule. Plant growth medium consisted of B5 major salts, Murashige and Skoog minor salts and organics, 400 mg l−1 glutamine, 100 mg l−1 arginine, 100 mg l−1 asparagine, 60 g l−1 sucrose, 8 g l−1 Difco Bacto agar and was supplemented with kinetin (0 – 13.94 μM) and 2,4-dichlorophenoxyacetic acid (2,4-D) (0 – 9.05 μM)
arranged as a 5×4 factorial in a randomized block design. Callus initiation occurred on a wide range of medium formulations
from megagametophyte explants; however, shoot formation occurred only on medium supplemented with 2.26 μM 2,4-D. In comparison,
callus initiation from explanted zygotic embryos occurred on fewer medium formulations, and adventitious shoot induction occurred
from callus on formulations with 9.29–13.94 μM kinetin + 0.45–9.05 μM 2,4-D. Rooted shoots, derived from megagametophyte and
zygotic embryo cultures, have been regenerated.
This revised version was published online in June 2006 with corrections to the Cover Date. 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.
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.
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
19.
María Laura Vidoz Pablo Klusacek Hebe Yolanda Rey Luis Amado Mroginski 《Plant Cell, Tissue and Organ Culture》2006,86(1):111-115
In vitro protocols for plant regeneration of Arachis correntina through both somatic embryogenesis and organogenesis were developed using immature leaves as explants. Morphologically normal somatic embryos were obtained on culture media composed of 20.70 or 41.41 μM picloram (PIC) with the addition of 0.044 μM 6-benzylaminopurine (BA), resulting in a 33 and 24% of conversion into plants, respectively. The source of explants and the developmental stage of the leaves had a marked effect on somatic embryogenesis. The second folded immature leaves from in vitro growing plants were the most responsive producing up to 30% embryogenesis in MS+41.41 μM PIC. Embryos converted into plants after transfer to MS medium devoid of growth regulators and these plants were successfully acclimatised. Adventitious shoots were obtained on culture media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) or naphthaleneacetic acid (NAA) with or without 0.044 μM BA, achieving plant regeneration in the induction media. The highest percentage of bud formation was obtained on culture medium composed of␣MS+10.74 μM NAA+0.044 μM BA (12.5%). Roots were formed on all culture media tested. Regenerated plants were transferred to pots and grew well under greenhouse conditions. 相似文献
20.
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