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1.
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
2.
Jing Li Yang Bo Zhao Eun Soo Seong Myong Jo Kim Won Hee Kang Na Young Kim Chang Yeon Yu Cheng Hao Li 《Plant biotechnology reports》2010,4(4):261-267
We describe culture conditions for a high-efficiency in vitro regeneration system of Papaver
nudicaule through somatic embryogenesis and secondary somatic embryogenesis. The embryogenic callus induction rate was highest when
petiole explants were cultured on Murashige and Skoog (MS) medium containing 1.0 mg l−1 α-naphthaleneacetic acid (NAA) and 0.1 mg l−1 6-benzyladenine (BA) (36.7%). When transferred to plant growth regulator (PGR)-free medium, 430 somatic embryos formed asynchronously
from 90 mg of embryogenic callus in each 100-ml flask. Early-stage somatic embryos were transferred to MS medium containing
1.0 mg l−1 BA and 1.0 mg l−1 NAA to germinate at high frequency (97.6%). One-third-strength MS medium with 1.0% sucrose and 1.0 mg l−1 GA3 had the highest frequency of plantlet conversion from somatic embryos (91.2%). Over 90% of regenerated plantlets were successfully
acclimated in the greenhouse. Secondary somatic embryos were frequently induced directly when the excised hypocotyls of the
primary somatic embryos were cultured on MS medium without PGRs. Sucrose concentration significantly affected the induction
of secondary embryos. The highest induction rate (89.5) and number of secondary somatic embryos per explant (9.3) were obtained
by 1% sucrose. Most secondary embryos (87.2–94.3%) developed into the cotyledonary stage on induction medium. All cotyledonary
secondary embryos were converted into plantlets both in liquid and on semisolid 1/3-strength MS medium with 1.0% sucrose. 相似文献
3.
A. Śliwińska O. Olszowska M. Furmanowa A. Nosov 《In vitro cellular & developmental biology. Plant》2008,44(2):69-77
Efficient plant regeneration through somatic embryogenesis was achieved in Polyscias filicifolia. Embryogenic calluses were induced on Murashige and Skoog (MS) basal medium supplemented with 0.5 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 mg l−1 benzylaminopurine (BAP; type I callus) and on MS medium with 2.0 mg l−1 2,4-D and 0.01 mg l−1 kinetin (type II callus) from leaf explants of a 2-yr-old plant. Primary somatic embryos (PSEs) developed after four passages
of suspension culture established from embryogenic callus when cultured in liquid half-strength MS medium (1/2 MS) without
growth regulators. PSEs in the cotyledonary stage were multiplied by adventitious embryogenesis. Single secondary somatic
embryos (SSEs) or their clusters developed at the base of PSE hypocotyls and regenerated into plantlets in a one-step process
on plant growth regulator-free 1/2 MS medium. Low sucrose concentration of 15 g l−1 promoted development of normal SSEs. All SSEs regenerated into single, well-rooted plantlets on a Nitsch and Nitsch medium
supplemented with 0.5 mg l−1 kinetin, 0.1 mg l−1 indole-3-butyric acid, and 10 mg l−1 adenine sulfate. Subsequent two subculture cycles on the same medium were necessary to obtain plantlets sufficiency developed
to allow successful transfer to the soil. Rooted plantlets were established in a peat mixture with 90% survival, with the
plants showing normal morphological characteristics. 相似文献
4.
Ai Hua Chen Jing Li Yang Yu Da Niu Chuan Ping Yang Gui Feng Liu Chang Yeon Yu Cheng Hao Li 《Plant Cell, Tissue and Organ Culture》2010,102(3):357-364
We developed a new protocol for highly efficient somatic embryogenesis and plantlet conversion of Schisandra chinensis. Friable embryogenic callus was induced from cotyledonary leaves and hypocotyls of germinated zygotic embryos on Murashige
and Skoog (MS) agar medium containing 2,4-dichlorophenoxyacetic acid (2,4-D). Preculture of zygotic embryos on 2,4-D-containing
medium increased embryogenic callus induction efficiency. The highest embryogenic callus induction frequency of 56.7% was
obtained from shoot apical meristem-containing hypocotyl explants from 1-week-old germinated embryos on MS medium containing
4.0 mg l−1 2,4-D. Embryogenic callus proliferation, somatic embryo (SE) formation, and subsequent plantlet conversion occurred under
optimal culture conditions. The effects of MS medium strength, sucrose, gibberellic acid (GA3), and 6-benzyladenine (BA) on SE formation and plantlet conversion were evaluated. Low MS medium strength (1/4 to 1/2) was
necessary for SE formation, and the optimal sucrose concentration was 2.0%. Supplementing medium with GA3 negatively impacted SE formation and subsequent development. BA significantly increased the number of SEs and the plantlet
conversion capacity. One-third-strength MS medium with 1.0% sucrose and 0.5 mg l−1 BA produced the highest number of SEs (309 embryos from 9 mg embryogenic callus) and the highest frequency of plantlet conversion
from germinated SEs (52.6%). When transplanted to soil, 90% of the regenerated plants developed into normal plants. 相似文献
5.
Myung Jin Oh Hye Ryun Na Hong-Keun Choi Jang Ryol Liu Suk Weon Kim 《Plant biotechnology reports》2010,4(2):125-128
Culture conditions were established for high frequency plant regeneration via somatic embryogenesis from cell suspension cultures
of Nymphoides coreana. Zygotic embryos formed pale-yellow globular structures and calluses at a frequency of 85.6% when cultured on half-strength
Murashige and Skoog (MS) medium supplemented with 0.3 mg l−1 of 2,4-D. However, the frequency of pale-yellow globular structures and white callus formation decreased slightly with an
increasing concentration of 2,4-D up to 10 mg l−1 with the frequency rate falling to 16.7%. Cell suspension cultures were established from zygotic embryo-derived calluses
using half-strength MS medium supplemented with 0.3 mg l−1 of 2,4-D. Upon plating onto half-strength MS basal medium, over 92.3% of cell aggregates gave rise to numerous somatic embryos
and developed into plantlets. Regenerated plantlets were successfully transplanted into potting soil and achieved full growth
to an adult plant in a growth chamber. The high frequency plant regeneration system for Nymphoides coreana established in this study will be useful for genetic manipulation and cryopreservation of this species. 相似文献
6.
K. Balaraju S. Saravanan P. Agastian S. Ignacimuthu 《Acta Physiologiae Plantarum》2011,33(4):1123-1133
An improved method of direct somatic embryogenesis (SE) was developed in Swertia chirata for the first time using leaves and roots of in vitro-grown young seedlings. In the present study, 2,4-dichlorophenoxyacetic
acid (2,4-D) was assessed individually and in combination with other auxins, as well as with cytokinin for its effectiveness
to induce somatic embryos. Leaf explants with abaxial side in the medium produced maximum number of somatic embryos. This
system omits the callus stage and thus reduces the process of SE in S. chirata by 35–45 days. Embryos at different stages of development were observed. Maturation of heart stage embryos were observed
on Murashige and Skoog (MS) medium containing 1 mg L−1 2,4-D. Upon transfer to the germination medium, they were converted to cotyledonary stage and then plantlets of 33% and 68%
of them were converted to cotyledonary stage and then plantlets on MS medium supplemented with 0.05 and 0.1 mg L-1 GA3 respectively. The 2,4-D alone at 1.0 or 1.5 mg L−1 was found to be better for embryogenic tissue initiation than 2,4-D in combination with indole-3-acetic acid or α-naphthalene
acetic acid. For further embryo development, 2,4-D was combined with cytokinins such as 6-benzylaminopurine (BAP) and kinetin
or plant growth regulator free medium or medium with 50% reduced concentration of the same hormone while subculturing. Mean
germination and percentage of survival were maximum in the medium containing 1.0 mg L−1 2,4-D in combination with 0.1 mg L−1 BAP. Regenerated plantlets were morphologically and genetically identical. This method offers a vast scope for the clonal
propagation of endangered plants. 相似文献
7.
A three-stage procedure for embryogenesis in Trachyspermum ammi was developed from cotyledon and cotyledonary node explants cultured in Murashige and Skoog (MS) liquid medium supplemented
with 0.2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D). Globular somatic embryos without intervening callus phase developed in 4 wk. The
development of embryos to heart and torpedo stages required second-stage subculture of the explants (along with developing
embryos) in liquid medium with lower concentrations of 2,4-D. Further development of embryos required a third-stage subculture
in hormone-free liquid medium supplemented with 100 mg l−1 casein hydrolysate. Regeneration of complete plantlets occurred after the fully developed somatic embryos were transferred
to solidified half-strength MS medium supplemented with 1 mg l−1 gibberellic acid. 相似文献
8.
A. Othmani C. Bayoudh N. Drira M. Marrakchi M. Trifi 《Plant Cell, Tissue and Organ Culture》2009,97(1):71-79
Plant regeneration through somatic embryogenesis from young leaf explants (5–10 mm long) adjacent to the apex of 5–6 year
old offshoots of Tunisian date palm (Phœnix dactylifera L.), cultivar Boufeggous was successfully achieved. Factors affecting embryogenic callus initiation, including plant growth
regulators and explant size, were investigated. The highest induction frequencies of embryogenic calli occurred after 6–7 months
on MS medium supplemented with 10 mg l−1 2,4-D and 0.3 mg l−1 activated charcoal. The subculture of these calli onto maintenance medium resulted in the formation of proembryos. Fine chopping
and partial desiccation (6 and 12 h) of embryogenic calli with proembryos prior to transfer to MS medium supplemented with
1 mg l−1 ABA stimulated the rapid maturation of somatic embryos. Maturated somatic embryo yield per 0.5 g FW of embryogenic callus
was 51 embryos with an average maturation time of 55 days. This was increased to 422 with finely chopped callus, and 124 and
306 embryos following 6 and 12 h desiccation treatments, respectively. The average time to maturation for these 3 treatments
was 35, 43 and 38 days, respectively. Subsequent substitution of ABA in MS medium with 1 mg l−1 NAA resulted in the germination and conversion of 81% of the somatic embryos into plantlets with normal roots and shoots.
The growth of regenerated somatic plants was also monitored in the field. 相似文献
9.
Iyyakkannu Sivanesan Mi Young Lim Byoung Ryong Jeong 《Plant Cell, Tissue and Organ Culture》2011,107(2):365-369
A simple and efficient protocol was developed for somatic embryogenesis from leaf and petiole explants of Campanula punctata Lam. var. rubriflora Makino. Somatic embryos (SE) were obtained with greater frequency from petiole explants than from leaf explants when cultured
on Murashige and Skoog (MS) medium supplemented with 2.0 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 mg L−1 6-benzyladenine (BA). On this medium, a mean number of 19.5 and 31.2 SE were developed per leaf and petiole explants, respectively.
Embryos were induced both light and dark conditions but culturing the explants 2 weeks in the dark followed by 3 weeks under
light resulted in high frequency of embryo formation. Globular embryos germinated best on MS medium supplemented with 0.3%
(w/v) activated charcoal (AC) and 1.0 mg L−1 GA3. The germinated plantlets grew further on MS medium containing 0.3% AC. Plantlets were successfully acclimatized in the greenhouse
with 94% survival rate. This is the first report on induction of somatic embryogenesis in this genus and also has implications
for genetic transformation, and mass clonal propagation. 相似文献
10.
Qian Zhang Jianjun Chen Richard J. Henny 《Plant Cell, Tissue and Organ Culture》2006,84(2):100161-100168
A simple and effective method of regenerating Syngonium podophyllum ‘Variegatum’ via direct somatic embryogenesis has been established. Leaf and petiole explants were cultured on Murashige
and Skoog (MS) medium supplemented with N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) or N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (TDZ) with either α-naphthalene acetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D). Somatic embryos directly formed at one or two sides of petiole explants on MS medium supplemented 2.5 mg l−1 TDZ with 0.5 mg l−1 NAA or 2.0 mg l−1 TDZ with 0.2 mg l−1 NAA or with 0.2 and 0.5 mg l−1 2,4-D, respectively. The frequency of petiole explants with somatic embryos produced was as high as 86% when cultured on medium
containing 2.5 mg l−1 TDZ with 0.5 mg l−1 NAA. Up to 85% of somatic embryos were able to germinate after transferring onto medium containing 2.0 mg l−1 6-benzylaminopurine (BA) and 0.2 mg l−1 NAA. Approximately 50–150 plantlets were regenerated from a single petiole explant. However, there was no somatic embryo
formation from leaf explants regardless of growth regulator combinations used. Regenerated plantlets from petiole explants
were stable and grew vigorously after transplanting to a soilless container substrate in a shaded greenhouse. 相似文献
11.
Kailash Choudhary M. Singh M. S. Rathore N. S. Shekhawat 《Plant biotechnology reports》2009,3(3):205-211
An efficient in vitro regeneration protocol for moth bean [Vigna aconitifolia (Jacq.) Marechal] via somatic embryogenesis has been developed. Embryogenic callus cultures were established from the cotyledonary
node as explant on semi-solid Murashige and Skoog (MS) medium supplemented with 0.75 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 6-benzylaminopurine (BA) and with various additives (50 mg l−1 ascorbic acid and 25 mg l−1 each of adenine sulphate, citric acid and l-arginine). Numerous somatic embryos differentiated on MS basal nutrient medium supplemented with 0.25 mg l−1 2,4-D and 0.5 mg l−1 of kinetin (Kin). Sustained cell division resulted in the formation of cell aggregates, which progressed to the globular-
and heart-shaped somatic embryos and then, if they differentiated properly, to the torpedo shape and cotyledonary stages.
The transfer of embryos onto fresh MS basal medium containing 0.2 mg l−1 BA and 2.0 mg l−1 gibberellic acid enabled the embryos to achieve complete maturation and germination. More than 80% of somatic embryos were
converted into true-to-type fertile plants. In vitro-regenerated plantlets with well-developed roots were successfully hardened
in a greenhouse and established in soil. 相似文献
12.
Rapid propagation of Eleutherococcus senticosus via direct somatic embryogenesis from explants of seedlings 总被引:5,自引:0,他引:5
Explants from three different parts (cotyledon, hypocotyl or root) of one week-old seedlings of Eleutherococcus senticosus were cultured on Murashige and Skoog (MS) medium with 1.0 mg l-1 2,4-D. Somatic embryos were formed directly from the surfaces of explants. The frequency of direct somatic embryo formation
was the highest in the hypocotyl segments (75%) as compared to cotyledon (56%) or root segments (12%). When hypocotyl explants
from 3 different stages of seedlings (zero, one or three week-old) were cultured on MS medium with 1.0 mg l-1 2,4-D, the frequency of somatic embryo formation rapidly declined as the zygotic embryos germinated. However most somatic
embryos (93%) from explants of zygotic embryos developed as fused state (multiple embryo), whereas somatic embryos (over 89%)
from more developed seedlings developed into single state (single embryo). Single embryos germinated and regenerated into
plantlets with both shoots and roots, while multiple embryos only regenerated into only multiple shoots. Plantlets that regenerated
from single embryos of E. senticosus were acclimatized in a greenhouse.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
13.
Qi Zhao Chuanfang Wu Wenguo Wang Shu Yuan Jinku Bao Fang Chen 《Plant Cell, Tissue and Organ Culture》2009,99(3):269-275
Polygonatum cyrtonema Hua. lectins (PCLs) were extracted from plantlets regenerated from rhizome explants of P. cyrtonema. Rhizome explants demonstrated a high frequency of callus induction (72.5%) and adventitious shoots differentiation (83.7%)
on Murashige Skoog (MS) medium supplemented with 2.0 mg l−1 2,4-dichlorophenoxyacetic acid and 1.0 mg l−1 6-benzyladenine. The adventitious shoots could root readily on 1/2 MS medium + 0.5 mg l−1 α-naphthaleneacetic acid and regenerate plantlets with a survival rate of 75.0%. Regenerated rhizomes were freeze-dried,
macerated and prepared for total RNAs and proteins extraction. The PCL gene was cloned and its expression level was measured by RT-PCR. Western blot using a lectin-specific antibody revealed a
similar amount in regenerated rhizomes compared to wild rhizomes, Furthermore, lectin derived from regenerated rhizomes retained
its ability to haemagglutinate rabbit blood cells. 相似文献
14.
This study describes culture conditions for a plant regeneration system via a combined pathway of somatic embryogenesis and
organogenesis in root explant cultures of the commercial rose cultivar 'Charming'. Root explants formed white calluses at
a frequency of 30% after 6 weeks of culture on Schenk and Hildebrandt (SH) medium supplemented with 11 mg l−1 2,4-dichlorophenoxyacetic acid. After 6 weeks of transfer to SH medium without growth regulators, initial white calluses
gave rise to globular somatic embryos at a frequency of 2.8%, which were subsequently dedifferentiated to embryonic tissues.
Somatic embryos or embryonic tissues initially derived from root explants did not undergo development beyond cotyledonary
stage. To produce adventitious shoots, embryonic tissues were sliced and cultured on SH medium with 0.5 mg l−1 6-benzyladenine. After 4 weeks of culture, 28% of embryonic tissue explants formed adventitious shoots. Regenerated shoots
were rooted on half strength SH medium with 0.1 mg l−1 α-naphthalaneacetic acid and subsequently grown to maturity. Root-derived embryonic tissues were proliferated by subculture,
while retaining the capacity for shoot production for a few years. 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.
Plant regeneration was achieved through direct and indirect somatic embryogenesis in Eucalyptus camaldulensis. Callus was induced from mature zygotic embryos and from cotyledon explants collected from 10, 15, 25, and 30-day-old seedlings
cultured on Murashige and Skoog (MS) basal medium supplemented with different concentrations of naphthaleneacetic acid (NAA).
Maximum callus induction from mature zygotic embryos was obtained on MS basal medium containing 1 mg l−1 NAA. The frequency of callus development varied based on the age of the cotyledon explants 10-day-old explants giving highest
percentage on MS basal medium supplemented with 1 mg l−1 NAA. Callus obtained from mature zygotic embryos gave highest frequency of somatic embryogenesis on MS basal medium containing
0.5 mg l−1 benzyladenine (BA) and 0.1 mg l−1 NAA. Separate age wise culture of the calli, obtained from cotyledons of different ages cultured separately, revealed high
somatic embryogenic potential on callus from 10-day-old cotyledons. Direct somatic embryogenesis too was obtained from hypocotyl
explants without an intervening callus phase on MS basal medium containing 0.5 mg l−1 BA. The effects of abscisic acid (ABA), sucrose, and different strengths of MS medium on somatic embryo maturation and germination
were also investigated. Number of mature somatic embryos increased with lower concentrations (0–1 mg l−1) of ABA while no significant differences were observed at higher concentrations (2–5 mg l−1) of ABA. Compared to basal medium containing lower concentrations of sucrose (1%), the MS medium supplemented with higher
levels of sucrose (4%) showed significantly lower frequency of mature somatic embryos. Basal medium without any dilution gave
the highest number of immature embryos. However, the number of mature embryos was high at higher medium dilutions. 相似文献
17.
Guang-Zhe Lin Xiao-Mei Zhao Soon-Kwan Hong Yu-Ji Lian 《Plant Cell, Tissue and Organ Culture》2011,106(1):93-103
We have developed a system for the in vitro regeneration of pasqueflowers (Pulsatilla koreana Nakai). The system was based on somatic embryogenesis and shoot organogenesis. Over a growth period of 6 weeks, multiple
shoots were initiated from leaf, petiole, and pedicel explants on Murashige and Skoog (MS) medium containing 0.5 mg l−1 indole-3-acetic acid (IAA) and zeatin (Zn), kinetin (Kin), or 6-benzyladenine (BA). We achieved 100% of adventitious shoot
induced when petiole and pedicel explants were cultured on MS, 0.5–2.0 mg l−1 Zn, and 0.5 mg l−1 IAA. Somatic embryos developed from the explants and generated shoots on MS medium containing 0.25 mg l−1 Zn and 0.5 mg l−1 IAA. Globular and heart-shaped stages of somatic embryos were observed. Histological studies have revealed the stages of
development of somatic embryos. For propagation and growth, the regenerated shoots from organogenic or embryogenic calluses
were transferred to MS medium containing either (1) 1.5 mg l−1 Zn and 0.05 mg l−1 IAA or (2) 1.0 mg l−1 BA and 0.05 mg l−1 IAA. After the length of the shoots reached 3 cm, the shoots initiated by organogenesis as well as those initiated by somatic
embryogenesis were transferred to the root induction medium. After 2 months of culture in half-strength MS with 1.5 mg l−1 α-naphthalene acetic acid (NAA), the rooting ratio was 93%. Finally, the rooted plantlets were acclimatized in a mixture
of mountain soil and perlite. 相似文献
18.
Microscopy and flow cytometry (FCM) were used to study somatic embryogenesis (SE) from zygotic embryos of Trifolium nigrescens Viv. to determine if there were any relationships between characteristics of somatic embryos (morphology, anatomy, genome
size stability) and their regenerability. Embryoids were induced on Murashige and Skoog (MS) medium containing 4 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 2 mg l−1 N6-[2-isopentenyl]-adenine (2iP) either directly from hypocotyls or via an intervening callus, depending on the duration of
culture. The morphology of somatic embryos varied from zygotic-like structures to abnormal structures including horn-shaped,
polycotyledonary, and fused embryoids. The incidence of abnormalities was higher in callus cultures than in direct regeneration.
Horn-shaped embryoids were the most frequent type of abnormal embryos. Only embryoids having zygotic-like morphology regenerated
into plantlets. Histological observations revealed that the absence of shoot and root apical meristems along with parenchymatization
of embryos were major obstacles to conversion of horn-shaped embryoids. The estimated 2C value for T. nigrescens was 0.9 pg. FCM analysis revealed differences in DNA content between embryoids induced via an intervening callus and those
produced directly from explants. Individuals with species-specific as well as increased DNA content were detected among those
zygotic-like embryos derived from callus, but all horn-shaped embryoids had increased genome sizes. The observed lack of differences
in DNA content between zygotic-like and horn-shaped embryoids, from direct SE, indicated that these phenotypic abnormalities
were of physiological origin. The mean DNA content of regenerants was species-specific, suggesting that only diploid embryoids
were capable for regeneration into plantlets. 相似文献
19.
Sujay Rakshit Zerka Rashid J. C. Sekhar T. Fatma Sain Dass 《Plant Cell, Tissue and Organ Culture》2010,100(1):31-37
Callus induction and regeneration ability of five elite maize inbred lines, CM 111, CM 117, CM 124, CM 125 and CM 300 were
investigated using 14-day-old immature embryos as explants. Genotype, medium, source of auxin and their concentrations influenced
induction of callus. Explants grown on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid at
1 mg l−1 showed the highest frequency of callusing. Among all the media tested, explants grown on N6 medium gave the highest frequency
of organogenic callus. Moreover, N6 supplemented with Dicamba promoted higher callus response in terms of both frequency of
induction as well as quality, compared to N6 medium with 2,4-D. N6 supplemented with 2 mg l−1 Dicamba induced the highest frequency of organogenic callus. Among the five genotypes tested, CM 124, CM 125, and CM 300
gave the best callus. Explants of both CM 124 and CM 300 incubated on MS medium supplemented with 1 mg l−1 benzyladenine and 0.5 mg l−1 indole acetic acid promoted the highest frequency of shoot induction. Though CM 124 induced higher percentage of shoot formation
than CM 300, the mean number of developed shoots per explant was higher for CM 300. The highest frequency of root formation
was observed when shoots were grown on MS medium supplemented with 2 mg l−1 naphathalene acetic acid. Percentage of regenerated plants ranged from 54 to 66. 相似文献
20.
N. Irvani M. Solouki M. Omidi A. R. Zare S. Shahnazi 《Plant Cell, Tissue and Organ Culture》2010,100(3):293-299
Dorema ammoniacum D. Don. (Apiaceae), a native medicinal plant in Iran, is classified as a vulnerable species. Root, hypocotyl, and cotyledon
segments were cultured on Murashige and Skoog (MS) (1962) medium supplemented with either 2,4-dichlorophenyoxyacetic acid
(2,4-D) or naphathalene acetic acid (NAA), at 0–2 mg l−1, alone or in combination with either benzyladenine (BA) or kinetin (KN), at 0–2 mg l−1 for callus induction. The best response (100%) was observed from root segments on MS medium containing 1 mg l−1 NAA and 2 mg l−1 BA. The calli derived from various explants were subcultured on MS medium supplemented with BA (1–4 mg l−1) alone or in combination with NAA or indole-3-butyric acid (IBA), at 0.2 or 0.5 mg l−1 for shoot induction. Calli derived from hypocotyl segments showed significantly higher frequency of plantlet regeneration
and number of plantlets than the calli derived from root and cotyledon segments. Therefore, MS medium supplemented with 2 mg l−1 BA and 0.2 mg l−1 IBA produced the highest frequency of shoot regeneration (87.3%) in hypocotyl-derived callus. The optimal medium for rooting
contained 2.5 mg l−1 IBA on which 87.03% of the regenerated shoots developed roots with an average number of 5.2 roots per shoots within 30 days.
These plantlets were hardened and transferred to the soil. The described method can be successfully employed for the large-scale
multiplication and conservation of germplasm this plant. 相似文献