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1.
Eugène K. Konan Justin Y. Kouadio Albert Flori Tristan Durand-Gasselin Alain Rival 《In vitro cellular & developmental biology. Plant》2007,43(5):456-466
In vitro rooting of oil palm shoots derived from somatic embryos was achieved through a single-phase protocol in which three shoots
are cultured in the same culture tube on an α-naphtaleacetic acid-enriched culture medium. Rooting performance was dependent
on both the genetic origin and initial size of the shoot explants. All shoots from a given tube showed a tendency to give
roots of the same type, independent of the original size of the explant. Whatever the clonal line, longer-size shoots (L-type:
>9 cm) showed higher rooting rates than medium-size (M-type: 7–9 cm) and short-size ones (S-type: 5–7 cm). When groups of
three shoots from the same clonal line were rooted together in the same culture tube, the combination of plant size within
the group impacted overall quality of rooting. Within triplets of shoots containing more than one short individual, the probability
of obtaining adequate rooting was low. Similarly, when more than one long shoot was included in the triplet rooting, quality
was also poor. By avoiding such combinations, the rate of well-rooted plantlets increased by 25%, with a maximum of 66% when
triplets of S/M/L combination were used. Smaller shoots, which usually showed poor rooting performance, were therefore found
to benefit from the presence of their neighbors. This interaction between the sizes of individuals in a given tube was found
to be associated with a within-tube correlation effect, a phenomenon previously described as “event coupling,” which was estimated
using a distorted binomial-type distribution of probabilities. The resulting calculation of a coupling factor (average r = 0.60) explains the behavior of shoots within the same culture tube and their average rooting performance. Modeling of the
interactions that occurred during in vitro rooting is described here and is recommended for improvement of this critical step in micropropagation. 相似文献
2.
High-frequency plant regeneration via somatic embryogenesis and organogenesis and in vitro flowering of regenerated plantlets in Panax ginseng 总被引:4,自引:0,他引:4
W. Tang 《Plant cell reports》2000,19(7):727-732
The morphogenesis ability of light yellowish globular callus derived from cotyledons of mature zygotic embryos of Panax ginseng was investigated. The optimal media for somatic embryogenesis and shoot organogenesis were MS medium containing 0.5 mg l–1 2,4-dichlorophenoxyacetic acid, 0.1 mg l–1 6-benzyladenine (BA), and 500 mg l–1 lactoalbumin hydrolysate, and SH medium supplemented with 0.5 mg l–1 α-naphthaleneacetic acid, 0.1 mg l–1 BA, and 500 mg l–1casein hydrolysate. The influences of glucose, mannose, fructose, and sorbose in the media on somatic embryogenesis and shoot
organogenesis were revealed as differences in the numbers of somatic embryos and adventitious shoots per gram of morphogenic
callus. The best regeneration of somatic embryos was obtained on medium containing glucose, with a mean of 8.7 somatic embryos
per gram of callus. The best regeneration of shoots was observed on medium containing fructose, with an average of 12.2 adventitious
shoots per gram of callus. Of the somatic embryos 95% were converted into regenerated plantlets, and 100% of adventitious
shoots rooted to form regenerated plantlets. Regenerated plants were successfully established in soil. Flowering was observed
in 5.7% of the regenerated plants derived from shoot organogenesis and in 1.4% of the regenerated plants derived from somatic
embryogenesis.
Received: 1 December 1998 / Revision received: 13 September 1999 / Accepted: 20 September 1999 相似文献
3.
Somatic embryogenesis was induced in expanding leaf explants excised from epicormic shoots forced from branch segments taken at four different times of year from a mature oak (Quercus robur L.). Branch segments 2–4 cm in diameter produced most shoots when collected in March. Somatic embryos were induced on explants derived from branches of all collection dates, although collection in November seemed to afford the best results. Germination and conversion ability of embryos of embryogenic lines derived from six oak trees depended heavily on genotype, conversion rates ranging from 0 to 70%. RAPD analyses found no evidence of genetic variation either within or between the embryogenic lines established from three of these trees, or between these lines and the trees of origin, or between somatic embryo derived plantlets and the trees of origin. The embryogenic system used in this study appears to be suitable for true-to-type clonal propagation of mature oak genotypes. 相似文献
4.
Xingyu Yang Jinfeng Lü Jaime A. Teixeira da Silva Guohua Ma 《Plant Cell, Tissue and Organ Culture》2012,109(2):213-221
Primulina tabacum is a rare and endangered species that is endemic to China. Establishing an efficient regeneration system is necessary for
its conservation and reintroduction. In this study, when leaf explants collected from plants grown in four ecotypes in China
are incubated on Murashige and Skoog (MS) medium containing 5.0 μM thidiazuron (TDZ) for 30 days, then transferred to medium
containing 5.0 μM 6-benzyladenine (BA), adventitious shoots are then observed. Conversely, when leaf explants are incubated
on medium containing 5.0 μM BA for 30 days, then transferred to medium containing 5.0 μM TDZ, somatic embryogenesis is induced.
This indicates that somatic embryogenesis and shoot organogenesis could be switched simply by changing the order of two cytokinins
supplemented in the culture medium. Histological investigation has revealed that embryogenic cells are induced within 30 days
following incubation of explants in medium containing TDZ. Only if embryogenic cells were induced, TDZ could enhance somatic
embryogenesis and BA could stimulate shoot organogenesis. When comparing explants from different ecotypes, leaf explants
from Zixiadong in Hunan Province could induce low numbers (1–2) of either somatic embryos or adventitious shoots on medium
containing either 5.0 μM TDZ or 5.0 μM BA, respectively. Whereas, leaf explants from plants collected from the other three
ecological habitats could induce 50–70 somatic embryos/adventitious shoots per explant. Moreover, somatic embryos could induce
secondary somatic embryogenesis and adventitious shoots on different media. All regenerated shoots developed adventitious
roots when these are transferred to rooting medium, and over 95% of plantlets have survived following acclimatization and
transfer to a potting mixture (1:1, sand:vermiculite). 相似文献
5.
Sandra Correia Maria Ludovina Lopes Jorge M. Canhoto 《Trees - Structure and Function》2011,25(6):1009-1020
Somatic embryogenesis is a valuable tool for plant breeding. In recent years, different aspects related to somatic embryogenesis
(SE) induction in tamarillo have been studied at our laboratory. In this work, results concerning the establishment of a protocol
for cloning an adult tamarillo tree through SE are presented. Attempts to induce SE in tamarillo from various explants directly
taken from an adult tree were unsuccessful and only calli with no embryogenic potential were initiated. To overcome the lack
of potential of adult tissues for SE, an indirect approach was attempted in which shoots from an adult tree were first established
in vitro and then wounded leaves were used for SE induction. A low rate of embryogenic tissue formation was obtained (19.4%),
but it was in the range of initiation rates from leaf explants of in vitro cloned plantlets of different tamarillo cultivars
(red, orange and yellow) that originated from a single seedling (13.3–54.4%). High variation in SE initiation among juvenile
controls could not be explained by different organogenetic potential, as no significant differences in shoot proliferation
or rooting ability during micropropagation could be detected. Subcultures of embryogenic lines from the adult tree allowed
us to obtain a large amount of embryogenic tissue that, after 8 weeks on a PGR-free medium, gave an average of 111 plants
per gram of fresh mass of embryogenic tissue. A RAPD comparative analysis of somatic embryo-derived plantlets and the donor
tree confirmed that the plantlets had no variation in the DNA regions amplified by 12 primers. These results open the way
for large-scale cloning of elite tamarillo trees through SE. 相似文献
6.
G. H. Ma C. X. He H. Ren Q. M. Zhang S. J. Li X. H. Zhang B. Eric 《Biologia Plantarum》2010,54(2):361-365
An efficient propagation system via somatic embryogenesis and shoot organogenesis and plant regeneration system for endangered species Primulina tabacum Hance was established. Thidiazuron (TDZ) was the key plant growth regulator for inducing somatic embryogenesis and kinetin
(KIN) and 6-benzylaminopurine (BAP) were the key cytokinins for inducing shoot organogenesis from leaf explants. TDZ combined
with BAP or KIN in the induction Murashige and Skoog medium induced both somatic embryos and adventitious shoots. Leaf explants
with abaxial site in contact with the medium induced less somatic embryos or adventitious shoots compared to inversely placed
leaf explants and the optimum pH was 6.5–7.0. Secondary somatic embryos or adventitious shoot could be induced from primary
somatic embryos using TDZ and BAP. Shoots developed adventitious roots on rooting medium containing 0.5 μM indole-3-butyric
acid and 0.2 % activated carbon. Over 90 % of plantlets survived following acclimatization and transfer to potting mixture
(sand:Vermiculite:limestone; 1:2:1). 相似文献
7.
S. C. Debnath 《In vitro cellular & developmental biology. Plant》2009,45(2):122-128
An efficient system to regenerate shoots on excised leaves of greenhouse-grown wild lowbush blueberry (Vaccinium angustifolium Ait.) was developed in vitro. The effect of thidiazuron (TDZ) on adventitious bud and shoot formation from apical, medial, and basal segments of the leaves
was tested. Leaf cultures produced multiple buds and shoots with or without an intermediary callus phase on 2.3–4.5 μM TDZ
within 6 wk of culture initiation. The greatest shoot regeneration came from young expanding basal leaf segments positioned
with the adaxial side touching the culture medium and maintained for 2 wk in darkness. Callus development and shoot regeneration
depended not only on the polarity of the explants but also on the genotype of the clone that supplied the explant material.
TDZ-initiated cultures were transferred to medium containing 2.3–4.6 μM zeatin and produced usable shoots after one additional
subculture. Elongated shoots were dipped in 39.4 mM indole-3-butyric acid powder and planted on a peat:perlite soilless medium
at a ratio of 3:2 (v/v), which yielded an 80–90% rooting efficiency. The plantlets were acclimatized and eventually established in the greenhouse
with 75–85% survival. 相似文献
8.
Veena Agrawal Pratima Rani Sardar 《In vitro cellular & developmental biology. Plant》2007,43(6):585-592
In vitro regeneration through somatic embryogenesis as well as organogenesis using cotyledon of a woody medicinal legume, Cassia angustifolia is reported. The cotyledons dissected from semi-mature seeds, if inoculated on Murashige and Skoog’s medium (MS) supplemented
with auxin alone or in combination with cytokinin, produced direct and indirect somatic embryos. A maximum of 14.36 ± 2.26
somatic embryos per 20 mg of explants including callus were produced in 70% cultures on MS medium with 2.5 μM benzyladenine
(BA) + 10 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Although the percentage of embryogenic cultures was higher (83.33%) at
10 μM 2,4-D + 1 μM BA, the average number of somatic embryos was much less (7.6 ± 0.85) at this level, whereas at 2.5 μM BA
and 5 μM 2,4-D, there was a simultaneous formation of both somatic embryos and shoots. The somatic embryos, although started
germinating on the same medium, developed into full plantlets only if transferred to MS basal with 2% sucrose. Cytokinins
alone did not induce somatic embryogenesis, but formed multiple shoots. Five micromolar BA proved optimum for recurrently
inducing shoots in the competent callus with a maximum average of 12.04 ± 2.10 shoots and shoot length of 2.26 ± 0.03 cm.
Nearly 91.6% shoots (2–2.5 cm in size) organized an average of 5.12 ± 0.58 roots on half strength MS + 10 μM indole-3-butyric
acid. All the plantlets have been transferred successfully to soil. Types of auxin and its interaction with cytokinin significantly
influenced somatic embryogenesis. 相似文献
9.
Arbutus unedo L. is a species of strawberry tree, widely represented in the Mediterranean climates of southern Europe. Fruits are used
to make jellies and a spirit called “medronheira.” Shoot apices and nodal segments from epicormic and coppiced shoots of adult
plants were used for plant propagation. Shoot apices from epicormic shoots, which were developed in a growth chamber, showed
higher rates of in vitro establishment. The results also indicated that shoot apices are more effective for plant establishment than nodal segments,
with rates of establishment significantly higher after 12 wk of culture. Of the three basal media used in combination with
9.0 μM benzyladenine and 0.087 M sucrose, the FS medium with the micronutrients of the Murashige and Skoog medium gave the
highest rates of multiplication, especially when the parameter analyzed was the number of clusters formed. When shoot apices
from selected adult plants (AL01–AL06) were tested, the multiplication rate was not significantly different among the plants.
However, in the conditions tested, shoots from the clones AL1, AL2, and AL3 showed better development, whereas shoots from
AL4, AL5, and AL6 showed an impaired development and could not be rooted. Rooting was achieved in all the conditions tested,
even in the absence of auxin. The inclusion of an auxin significantly increased root formation, whereas the addition of charcoal
did not improve root formation. Rooted plantlets were acclimatized, and some of them are now in the field for further study. 相似文献
10.
Development and germination of American chestnut somatic embryos 总被引:8,自引:0,他引:8
Zizhuo Xing William A. Powell Charles A. Maynard 《Plant Cell, Tissue and Organ Culture》1999,57(1):47-55
American chestnut (Castanea dentata (Marsh.) Borkh.) plants were regenerated from developing ovules through somatic embryogenesis.
On an initiation medium containing 18.18 μM 2,4-dichlorophenoxyacetic acid and 1.11 μM 6-benzyladenine (BA), 25 out of 1,576
ovules were induced to form proembryogenic masses (PEMs). These PEMs were cultivated on a development medium for 4 weeks.
Individual somatic embryos were then grown on a maturation medium for at least one month, until shoot meristems and radicles
were developed. Both development and maturation media consisted of Gamborg's B-5 basal medium, 0.5 μM BA, and 0.5 μM α-naphthaleneacetic
acid, but the former contained 20 g l−1 sucrose and the later contained 60 g l−1 sucrose. A range of 86 to 586 embryos per gram PEMs was observed beyond the cotyledonary stage. These embryos then germinated,
resulting in plantlets with a 3.3% conversion rate. An additional 6.3% of the mature embryos produced shoots, which could
also result in plantlets by rooting of microcuttings. Proembryogenic masses that were established in continuous culture and
maintained on initiation medium for 17 months retained regenerability, though the embryo yield decreased over time. Twenty
plantlets were acclimatized and grown in potting mix in a greenhouse. The largest 6 were transplanted, along with seedling
controls, into a nursery bed in 1997. As of July, 1999, 4 out of the 6 were surviving.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
11.
B. A. Bergmann W. P. Hackett H. Pellett 《In vitro cellular & developmental biology. Plant》1996,32(3):161-164
Summary Somatic embryogenesis was observed with explants taken from four types ofAesculus tissue: (a) shoots of 4-wk-oldin vitro germinated excised embryos (seed fromA.×arnoldiana), (b) roots of 4-wk-oldin vitro germinated excised embryos (seed fromA.×arnoldiana), (c) shoots from newly forced 3-yr-old seedlings (A. glabra), and (d) newly forced shoots from a 30-yr-old tree (A.×arnoldiana “Autumn Splendor”). Shoots provided three types of explants, single node, shoot apex, and internodal section, and all exhibited
embryogenesis.
Proembryogenic masses developed in a few cases after 6 wk in culture but were more commonly seen after 3 mo. The yellow, friable
proembryogenic masses emerged from proximal cut ends of explants. Almost all cultures that formed embryos possessed leaves,
either from developing apical or axillary buds or from adventitious buds, prior to the emergence of proembryogenic masses.
Only tissues that had begun to senesce and had been exposed to cytokinin (benzyladenine at 5 or 25 μM) formed somatic embryos. Embryos with distinct cotyledonlike structures and root/shoot axes developed during the 10 to 16
wk following the inital emergence of proembryogenic masses. Enhanced frequency of embryogenesis was obtained by dark culture
of root and shoot explants from 4-wk-old germinated embryos (A.×arnoldiana) and by dark and cold (5°C) treatment of shoot tissue cultures derived from 3-yr-old seedlings (A. glabra). Embryogenic potential was greatest in the most juvenile tissue and least in the mature tissue. Five percent of shoot explants
taken from the 30-yr-old select treeA.×arnoldiana “Autumn Splendor” produced somatic embryos. 相似文献
12.
Direct somatic embryogenesis induced from cotyledons of mango immature zygotic embryos 总被引:3,自引:0,他引:3
Summary For the first time, regenerated plantlets were obtained from immature zygotic embryos of mango (Mangifera indica L.) through direct somatic embryogenesis. Pro-embryogenic mass (PEM)-like structures, which are differentiated as clusters
of globular structures, were easily induced directly from the abaxial side of cotyledons from immature fruits, 2.0–3.5 cm
diameter by a 2-wk culture period on a modified Murashige and Skoog medium with 5 mgl−1 (25μM) indole-3-butyric acid (IBA). Conversion of somatic embryos into plantlets was achieved after 4 wk of culture on the conversion
medium containing 5mgl−1 (23 μM) kinetin. Secondary somatic embryogenesis could also be obtained directly from the hypocotyls of mature primary somatic embryos
cultured on the conversion medium. In our experimental system, only minor problems were noted with browning of cultures. 相似文献
13.
Summary Micropropagated grape (Vitis vinifera L.) cv. Arka Neelamani cultures showed a decline in root and shoot growth performance after 6–7 yr of continuous in vitro culture. Indexing the culture medium using nutrient agar or 523 bacteriological medium (Viss et al., 1991) revealed covert
bacteria in 75–100% cultures. Testing the tissue from different parts of in vitro plantlets on nutrient agar showed bacteria comprising of six or more morphotypes in 100% of root and collar tissue samples
but less frequently in stem segments. The shoot tips had the lowest incidence of bacterial association. The whole shoots treated
with NaOCl (4% chlorine) or HgCl2 (0.1%) showed endophytic bacterial survival. Culturing the HgCl2-treated (5 min) shoot tips on antibiotic overlaid medium (1 ml of 50 mg l−1 gentamycin and/or cefazolin) in culture tubes (150×25 mm) for 1 mo. facilitated the cleansing of cultures with 75% recovery
of contaminant-free shoots as monitored through indexing for the next 2 yr. Repeated indexing of medium and tissue from various
plant parts during the first two to four subculture cycles following antibiotic treatment was instrumental in reliably identifying
clean cultures and preventing bacterial re-emergence. Antibiotic incorporation in the medium was detrimental to grape microcuttings.
Bacteria-freed cultures showed 80–100% rooting and a high number of plantlets that could be acclimatized. The plants put in
the field after 8 yr of active micropropagation showed some juvenile characteristics initially, which disappeared in 6–8 mo.,
and the pruned shoots showed flowering and bunch development within 1 yr of field planting. This indicated the feasibility
of keeping grape plants in vitro for long periods if covert microbes were eliminated. 相似文献
14.
Chun-Lai Zhang Dong-Fang Chen Malcolm C. Elliott Adrian Slater 《In vitro cellular & developmental biology. Plant》2001,37(2):305-310
Summary Improved in vitro tissue culture systems are needed to facilitate the application of recombinant DNA technology to the improvement of sugar
beet germplasm. The effects of N
6-benzyladenine (BA) and thidiazuron (TDZ) pretreatment on adventitious shoot and somatic embryogenesis regeneration were evaluated
in a range of sugar beet breeding lines and commercial varieties. Petiole explants showed higher frequencies of direct adventitious
shoot formation and produced more shoots per explant than leaf lamina explants. TDZ was more effective than BA for the promotion
of shoot formation. The optimal TDZ concentrations were 2.3–4.6 μM for the induction of adventitious shoot regeneration. Direct somatic embryogenesis from intact seedlings could be induced
by either BA or TDZ. TDZ-induced somatic embryogenesis occurred on the lower surface of cotyledons at concentrations of 0.5–2μM and was less genotype-dependent than with Ba. A high frequency of callus induction could be obtained from seedlings and leaf
explants, but only a few of the calluses derived from leaf explants could regenerate to plants via indirect somatic embryogenesis. These results demonstrated that TDZ could prove to be a more effective cytokinin for in vitro culture of sugar beet than BA. Rapid and efficient regeneration of plants using TDZ may provide a route for the production
of transgenic sugar beet following Agrobacterium-mediated transformation. 相似文献
15.
The regeneration of somatic seedlings from selected 100-year-old cork oak trees is reported. The induction of somatic embryogenesis from leaves of epicormic shoots was significantly affected by genotype, harvesting time and their interaction. Leaves from all five selected trees produced somatic embryos when the segments of branches used as sources of epicormic shoots were collected in May. Genotype, but not the level of photosynthetically active radiation, affected the proliferation of the embryogenic lines and the number of detachable embryos that could be obtained from them. Genotype also affected several steps leading to conversion of somatic embryos, from germination to complete acclimatisation of somatic seedlings. Almost 40% of the somatic embryos from all lines germinated, showing coordinated root and shoot growth. Although the mean percentage of recovery for the whole process was low, plants could be regenerated from four of the five trees tested. 相似文献
16.
Mohammed Shafi Ullah Bhuiyan Sung Ran Min Won Joong Jeong Sayeda Sultana Kwan Sam Choi Youngsook Lee Jang R. Liu 《Plant Cell, Tissue and Organ Culture》2011,104(1):69-77
The eucalypt Corymbia torelliana × C. citriodora is planted widely in India, Brazil and Australia although plantation establishment has been limited by inadequate seed supply
and low amenability to propagation via cuttings. This study optimised node culture and organogenic culture methods for in
vitro propagation of Corymbia hybrids by identifying explant position (topophysic) effects on rooting, shoot elongation and shoot proliferation. Strong,
negative morphogenic gradients in shoot elongation and proliferation capacity were evident from the cotyledonary node to the
fourth or fifth node of seedlings when their nodes were transferred to node culture (without benzyladenine). These topophysic
effects were related to differences in rooting capacity of individual nodes. Root formation in node culture was associated
with formation of long multi-nodal axillary shoots, and so higher rooting of shoots from the cotyledonary node or first true-leaf
node was associated with higher shoot proliferation. However, all nodes were equally capable of shoot proliferation in organogenic
culture (with 2.2 μM benzyladenine), where rooting and rapid stem elongation did not occur. Most shoots (61–100%) from both
node culture and organogenic culture were converted to plantlets, with plantlet conversion and primary root number not differing
significantly among explant node positions. The strong topophysic effect in node culture, combined with the lack of a topophysic
effect in organogenic culture, provides for an optimised clonal propagation system based on segregation of nodes from the
same seedling into separate node and organogenic culture pathways. 相似文献
17.
Teresa Martínez Elena Corredoira Silvia Valladares Lorena Jorquera Ana M. Vieitez 《Plant Cell, Tissue and Organ Culture》2008,95(3):341-351
Somatic embryos of Quercus robur L. belonging to lines derived from mature trees were germinated in experiments designed to determine the effects of pregermination
chilling and the temporary inclusion of thidiazuron (TDZ) in the germination medium. Germination response was evaluated in
terms of the percentages of embryos exhibiting root-only elongation, shoot-only elongation, or both (conversion to plantlets).
Conversion rates depended on genotype and were lower than those of oak zygotic embryonic axes germinated in vitro. Two months’
storage of somatic embryos at 4°C between maturation and germination treatments did not influence their conversion frequency,
although root-only germination was promoted in the three embryogenic lines investigated. Addition of 0.01–5.0 μM TDZ to the
germination medium for 7 or 18 days induced multiple shoot formation in the epicotyl region of germinating embryos, although
the 18-day treatment was detrimental with TDZ concentrations of 0.5–5.0 μM. Exposure to 0.05–0.1 μM TDZ for 7 days increased
the frequency of shoot-only elongation and decreased that of root-only elongation in embryogenic lines with both high and
low conversion ability, but whereas the conversion rate of the hard-to-convert line Sainza was significantly increased, that
of the readily converted line B-17 was negatively affected. As a result, with 0.1 μM TDZ the total potential plant recovery
of Sainza (the conversion rate plus the percentage of embryos exhibiting shoot-only germination) was 64%, approximately the
same as that of B-17. Shoots excised from shoot-only germinating embryos can be elongated and rooted by proven micropropagation
procedures. An additional result was the finding that adventitious bud regeneration was induced on the cotyledons of TDZ treated
embryos (69% with 0.5 μM TDZ), which may prove useful for genetic transformation. This study is the first to have shown that
TDZ can increase the germination efficiency of oak somatic embryos. 相似文献
18.
Iyyakkannu Sivanesan Ju Yeon Song Seung Jae Hwang Byoung Ryong Jeong 《Plant Cell, Tissue and Organ Culture》2011,105(1):55-63
A simple and efficient micropropagation system was developed for Cotoneaster wilsonii through node and shoot tip explants obtained from mature field-grown plants. Of the two explants, node explants were found
to be the most effective for axillary shoot proliferation. The highest frequency of shoot induction was achieved when nodal
explants were incubated on Murashige and Skoog (MS) medium supplemented with 0.5 mg L−1 thidiazuron (TDZ) and 0.1 mg L−1 α- naphthaleneacetic acid (NAA) with an average of 34 shoots per explant. The microshoots were separated from the multiple
shoots and subcultured on MS medium supplemented with 3% (w/v) sucrose and 0.8% (w/v) agar for further shoot growth. Maximum
rooting was obtained on half-strength MS medium supplemented with 0.5 mg L−1 indole-3-butyric acid (IBA). The in vitro-grown plantlets were successfully acclimatized in a glasshouse with 98% of survival.
High concentrations of TDZ (1.5–2.0 mg L−1) and repeated subcultures resulted hyperhydric shoots. Supplementation of the culture medium with silicon significantly reduced
the induction of hyperhydric shoots. Increasing silicon concentration significantly decreased malondialdehyde content of the
regenerated shoots. Data indicate that addition of silicon to the culture medium can effectively control hyperhydricity. 相似文献
19.
Giovanni Iapichino Marcello Airò 《In vitro cellular & developmental biology. Plant》2008,44(4):330-337
Multiple shoots were induced on stem segments of an 8-y-old plant of Metrosideros excelsa Sol ex Gaertn. “Parnel”. Axillary shoots produced on uncontaminated explants were excised, segmented, and recultured in the
same medium to increase the stock of shoot cultures. The Murashige and Skoog (MS) medium, augmented with different concentrations
of 2- isopenthenyladenine (2iP) and indole-3-acetic acid (IAA), either singly or in combinations, as potential medium for
shoot multiplication by nodal segments was tested. In the following experiment, equal molar concentrations of four cytokinins
[2iP, kinetin, zeatin, and N
6-benzyladenine (BA)] in combination with equal molar concentrations of three auxins [IAA, α-naphthaleneacetic acid (NAA),
and indole-3-butyric acid (IBA)] were tested for ability to induce axillary shoot development from single-node stem segments.
The highest rate of axillary shoot proliferation was induced on MS agar medium supplemented with 1.96μM 2iP and 1.14μM IAA
after 6 wk in culture. Different auxins (IAA, IBA, and NAA) were tested to determine the optimum conditions for in vitro rooting of microshoots. The best results were accomplished with IAA at 5.71μM (89% rooting) and with IBA at 2.85 or 5.71μM
(86% and 86% rooting, respectively). Seventy and 90 percent of the microshoots were rooted ex vitro in bottom-heated bench (22 ± 2°C) after 2 and 4 wk, respectively. In vitro and ex vitro rooted plantlets were successfully established in soil. 相似文献
20.
Myung Jin Oh Hye Ryun Na Hong-Keun Choi Jang Ryol Liu Suk Weon Kim 《Plant biotechnology reports》2008,2(1):87-92
An improved protocol for high frequency plant regeneration via somatic embryogenesis from zygotic embryo-derived cell suspension
cultures of watershield (Brasenia schreberi) was developed. Zygotic embryos formed pale-yellow globular structures and white friable callus at a frequency of 80% when
cultured on half-strength MS medium supplemented with 0.3 mg l−1 2,4-D. However, the frequency of formation of pale-yellow globular structures and white friable callus decreased slightly
with increasing concentrations of 2,4-D up to 3 mg l−1, where the frequency reached ~50% of the control. Cell suspension cultures from zygotic embryo-derived white friable callus
were established using half-strength MS medium supplemented with 0.3 mg l−1 2,4-D. Upon plating of cell aggregates on half-strength MS basal medium, approximately 8.3% gave rise to somatic embryos
and developed into plantlets. However, the frequency of plantlet development from cell aggregates was sharply increased (by
up to 55%) when activated charcoal and zeatin were applied. Regenerated plantlets were successfully transplanted to potting
soil and grown to normal plants in a growth chamber. The distinctive feature of this study is the establishment of a high
frequency plant regeneration system via somatic embryogenesis from zygotic embryo-derived cell suspension cultures of watershield,
which has not been previously reported. The protocol for plant regeneration of watershield through somatic embryogenesis could
be useful for the mass propagation and transformation of selected elite lines. 相似文献