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1.
Haploid/doubled haploid (DH) technology can aid plant breeding programs by accelerating production of homozygous lines, provided
enough viable DH progeny can be obtained from diverse haploid genotypes. In cases where there is a low frequency of spontaneous
doubling, chromosome doubling procedures are required to achieve fecundity. We produced 63 parthenogenetic melon plantlets
via pollination with γ-irradiated pollen, cloned them by nodal cuttings, and tested the effects of in vitro and in vivo colchicine
treatment on survival, ploidy, pollen production, and fruit recovery. The most effective procedure was in vitro exposure of
3 cm shoot tip explants to 500 mg/l colchicine for 3 h. This treatment gave 83% survival of explants and 26% conversion to
diploidy. Fruit recovery rate was 60% among plants with good pollen production. In vivo exposure of the tops of young plants
to 5000 mg/l for 2 and 4 h yielded some fruits but also resulted in less survival and more morphological abnormalities. Strategies
for recovery of progeny from parthenogenetic melon plants are recommended. To our knowledge, this study represents the first
comprehensive study of recovery of fruits and viable seeds from parthenogenetic melon plants. 相似文献
2.
We have developed improved procedures for recovery of haploid and doubled haploid (DH) melon plants, using hybrids derived from crosses of lines with multiple virus resistance. Seeds formed after pollination with irradiated pollen were cultured in liquid medium for 10 days before excision of the embryos for further culture. This made it easier to identify the seeds containing parthenogenetic embryos, thereby reducing the effort required and increasing the percentage of plants recovered. The plants obtained (approximately 175) were transferred to a greenhouse for evaluation. Three fertile lines were identified, and selfed seeds were obtained for evaluating virus resistance. Flow cytometry of leaf tissues showed that two of these lines were spontaneous DH and the third was a mixoploid containing haploid and diploid cells. The other plants remained sterile through the flowering stage. Flow cytometry of 20 sterile plants showed that all were haploid. Attempts to induce chromosome doubling by applying colchicine to greenhouse-grown plants were unsuccessful. Shoot tips from the haploid plants were used to establish new in vitro cultures. In vitro treatment of 167 micropropagated haploid shoots with colchicine produced 10 diploid plants as well as 100 mixoploid plants. Pollen from male flowers that formed in vitro on the colchicine-treated plants was examined. High percentages of viable pollen that stained with acetocarmine were found not only in the diploids but also in >60% of the plants scored as mixoploid or haploid by flow cytometry. Efficient recovery of DH from hybrid melon lines carrying combinations of important horticultural traits will be a valuable tool for melon breeders. 相似文献
3.
Diwakar Aggarwal Anil Kumar M. Sudhakara Reddy 《Plant Cell, Tissue and Organ Culture》2010,102(1):45-52
An efficient shoot organogenesis system has been developed from mature plants of selected elite clones of Eucalyptus tereticornis Sm. Cultures were established using nodal explants taken from freshly coppice shoots cultured on Murashige and Skoog medium
containing 58 mM sucrose, 0.7% (w/v) agar (MS medium) and supplemented with 2.5 μM benzyladenine (BA) and 0.5 μM α-naphthaleneacetic
acid (NAA). Shoot organogenesis was achieved from leaf segments taken from elongated microshoots on MS medium supplemented
with 5.0 μM BA and 1.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The addition of cefotaxime to the medium promoted shoot
differentiation, whereas carbenicillin and cephalexin inhibited shoot differentiation. Maximum shoot bud organogenesis (44.6%)
occurred in explants cultured on MS medium supplemented with 5.0 μM BA, 1.0 μM 2,4-D and 500 mg/l cefotaxime. Leaf maturity
influenced shoot regeneration, with maximum shoot organogeneisis (40.5%) occurring when the source of explants was the fifth
leaf (14–16 days old) from the top of microshoot. Shoot organogenic potential also varied amongst the different clones of
E. tereticornis. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) analyses indicated clonal uniformity of
the newly formed shoots/plants, and these were also found to be true-to-type. 相似文献
4.
Surya Prakash Johannes Van Staden 《In vitro cellular & developmental biology. Plant》2008,44(4):338-341
A method for in vitro regeneration of Searsia dentata from nodal and shoot tip explants derived from mature trees is outlined. Nodal explants produced multiple shoots from the
axis when cultured on Murashige and Skoog (MS) medium containing 3% sucrose supplemented with 0, 5, 7.5, 10, or 12.5 μM N
6-benzyladenine (BA). An average of 5.3 shoots was obtained from nodal explants on 10 μM BA. For shoot tip explants, however,
supplementation of α-naphthaleneacetic acid (NAA) with BA favored a caulogenic response. A maximum of 6.1 shoots were produced
per shoot tip explant on MS containing 7.5 μM BA plus 5.0 μM NAA. The in vitro-regenerated shoots produced roots when transferred
to full-strength MS medium containing 3% sucrose and 10 μM indole-3-butyric acid (IBA). The developed plantlets were transferred
initially to a mist house. After an initial acclimatization period of 3–4 mo, plantlets were shifted to the greenhouse where
they thrived for 9 mo. The standardized protocol for mass propagation of S. dentata should eliminate the dependence on natural stands of plants for traditional medicinal purposes, and will also serve as a
means of conservation as the species is heavily overexploited. 相似文献
5.
Bodhipadma Kitti Noichinda Sompoch Padyencheun Winan Khunthacharoen Theerapong Chikhunthod Utorn Leung David W. M. 《Plant Cell, Tissue and Organ Culture》2011,105(3):465-469
The shoots developed from both the shoot tip and nodal explants of feathered amaranth (Celosia argentea var. plumosa—feathered cockscomb or plumed cockscomb) after 8 weeks of culture in the presence of either paclobutrazol or benzyladenine
(BA) were shorter than those developed on basal Murashige and Skoog (MS) medium (Physiol Plant, 15:473–497, 1962) alone. However, this retarding effect was more pronounced in the nodal explant culture. Shoot tip explants from 2-week-old
seedlings were more adversely affected by 0.85 or 1.7 μM paclobutrazol than those from older seedlings. In contrast, regardless
of preculture duration investigated nodal explants did not exhibit different response to three different concentrations of
paclobutazol. The response to 2.2 or 4.4 μM BA appeared to be largely independent of the age of the shoot tip explants or
preculture treatment of nodal explants. Shoots developed from nodal explants produced a higher number of terminal inflorescence
than those from shoot tip explants. Moreover, only lateral shoots from nodal explant culture formed inflorescence. Increased
preculture duration on basal MS medium could generally lessen the inhibitory effect of lower concentrations of paclobutazol
or BA on terminal or lateral inflorescence formation in nodal explant culture. 相似文献
6.
A protocol for in vitro induction of crape myrtle tetraploids using nodes from in vitro-grown shoots (2n = 48) was established. Nodal buds were excised from in vitro-grown shoots, maintained on proliferation medium containing
Murashige and Skoog medium supplemented with 4.44 μM 6-benzyladenine , 0.54 μM α-naphthaleneacetic acid, and treated with
a range of concentrations of colchicine under three different conditions. Nodal bud explants treated in liquid proliferation
medium supplemented with either 15 or 20 mM colchicine for 24 h turned necrotic and died; whereas, those cultured on solid
proliferation medium supplemented with either 125 or 250 μM colchicine for 30 days survived, but no tetraploid plants were
obtained. However, when explants were cultured in liquid proliferation medium containing 250, 500 or 750 μM colchicine for
10 days, tetraploid plants (2n = 96) were obtained. Incubation of explants in medium containing 750 μM colchicine promoted the highest frequency of survival
(40%) of explants and of recovered tetraploids (60%). Morphological and anatomical characteristics of leaves, including leaf
index, stomata size and number, stomata index (length/width), and number of chloroplasts in guard cells correlated with ploidy
of crape myrtle plants. The number of chloroplasts in guard cells of stomata was a stable and reliable marker in discriminating
plants of different ploidy levels. Chromosome counts and flow cytometry confirmed these findings. 相似文献
7.
Kottackal Poulose Martin A. K. Pradeep Joseph Madassery 《Acta Physiologiae Plantarum》2011,33(4):1141-1148
Trichopus zeylanicus subsp. travancoricus (known as Arogyapacha), an endangered ethnomedicinal plant of the Western Ghats of South India, serves as the major source
of the commercial drug Jeevani. The present study established a long-term high frequency in vitro propagation protocol for Arogyapacha. Callus obtained from
the branch–petiole explants cultured on Murashige and Skoog (MS) medium with 4.5 μM 2,4-dichlorophenoxyacetic acid upon subculture
to medium with different concentrations of 6-benzyladenine (BA) either alone or in combination with an auxin favoured shoot
morphogenesis. Medium with 13.3 μM BA alone facilitated high frequency shoot bud (mean of 93.2) formation. Medium with lower
concentrations of BA (4.4, 6.6 and 8.8 μM) alone or in combination with lower concentration of α-naphthaleneacetic acid (NAA)
or indole-3-butyric acid (IBA) favoured better shoot growth than 13.3 μM BA containing medium, but with reduced number of
shoot buds. Subsequent cultures on medium with lower concentrations of BA and also on MS basal media facilitated shoot formation
as well as growth of shoots. The shoot regeneration potential showed no decline up to 5 years. Culture of the in vitro-derived
whole branch–leaf explants on MS basal medium developed shoots directly from the node. On medium with 19.6 μM IBA, the whole
branch–leaf explants induced nodular callus from the node, which developed shoots later. Subsequent cultures on medium with
BA exhibited high frequency shoot formation. The transfer of shoots after 10–15 days culture on half-strength MS medium containing
2.7 μM NAA to half-strength basal medium induced a mean of 11.3 roots. Field survival of plantlets relied on the soil mix:
a 1:4 ratio of sand and red-soil exhibited the highest plantlets survival (86.6%). RAPD profile of the source plant and plants
regenerated from calli after 4 years showed no polymorphism. The established plantlets with morpho-floral features similar
to that of the source plants flowered normally and set fruits. 相似文献
8.
An efficient regeneration protocol for rapid multiplication of Melia azedarach, an economically as well as medicinally important timber-yielding tree, was developed. Nearly 90% of the culture exhibited
axillary bud sprouting and multiple shoot formation from nodal segments derived from 20-year-old candidate plus tree on Murashige
and Skoog (MS) medium supplemented with 5 μM 6-benzyladenine (BA). The highest shoot regeneration frequency (92%), maximum
number of multiple shoots (19.7 ± 0.31) as well as shoot length (4.9 ± 0.08 cm) was induced from nodal explants on MS medium
amended with 5.0 μM BA, 0.5 μM indole-3-acetic acid (IAA) and 30 μM adenine sulfate (AdS). Addition of 250 mg l−1 ammonium sulphate, (NH4)2SO4, and 100 mg l−1 K2SO4, prevented defoliation and tip burning without affecting the number of shoots. The explant harvest period also influenced
the bud break and shoot sprouting from nodal segments. Repeated subculturing of nodal explants on fresh MS medium containing
lower concentration of BA (2.5 μM) along with IAA (0.5 μM), AdS (30 μM) and additives was found most suitable growth regulator
regime for achieving 1.2-fold increase in shoot multiplication rate. The percentage of shoot multiplication as well as the
number of shoots per node remained the same during first three subculture passages, afterwards a decline was recorded. About
90% of the in vitro regenerated shoots were successfully rooted ex vitro by giving a pulse treatment of 250 μM indole-3-butyric
acid for 15 min, followed by their transfer to thermocol cups containing soilrite. The raised plantlets were successfully
acclimatized first under culture room conditions, then to green house with 85% survival rate. 相似文献
9.
Qin-Mei Wang Feng-Zhan Gao Xiang Gao Fan-Yu Zou Xin Sui Meng Wang Yue-Jun Hui Li Wang 《Plant Cell, Tissue and Organ Culture》2012,109(2):191-200
An efficient in vitro micropropagation system for Clivia miniata Regel was developed using basal tissues of young petals and young ovaries as explants. For callus induction, explants were
incubated on Murashige and Skoog (MS) medium containing either 2.22 μM 6-benzyladenine (BA) and 4.52 μM 2,4-dichlorophenoxyacetic
acid (2,4-D) or 4.44 μM BA, 5.37 μM α-naphthaleneacetic acid (NAA), and 9.05 μM 2,4-D. Moreover, callus was induced from young
ovaries when these were incubated on MS medium containing 8.88 μM BA, 10.74 μM NAA, and 9.05 or 18.10 μM 2,4-D. Subsequently,
callus was transferred to MS medium supplemented with kinetin (KT) and NAA for shoot organogenesis. Frequency of shoot regeneration
from petal-derived callus was highest when callus was transferred to medium containing 2.69 μM NAA with either 9.29 or 13.94 μM
KT. Shoot regeneration frequency from ovary-derived callus was highest when this callus was transferred to medium containing
9.29 μM KT and 10.74 μM NAA. Overall, different explant types exhibited different organogenic capacities wherein, young petals
had higher shoot regeneration frequencies than young ovaries. The highest rooting frequency (98.25 ± 3.04%) was obtained when
shoots were transferred to half-strength MS medium without plant growth regulators. Regenerated plantlets were transplanted
to soil mix and acclimatized, yielding a 96.80% survival frequency. Only 0.6% of regenerated plantlets exhibited morphological
changes. The diploid status (2n = 22) of regenerated plantlets was determined using chromosome counts of root-tips. Moreover, inter-simple sequence repeats
were used to assess the genetic fidelity of regenerated plantlets. Overall, regenerated plants shared 90.5–100.0% genetic
similarities with mother plants and 89.0–100.0% similarities with each other. 相似文献
10.
Hamed Ebrahimzadeh Hassan Soltanloo Mehran E. Shariatpanahi Ali Eskandari Seiede Sanaz Ramezanpour 《Plant Cell, Tissue and Organ Culture》2018,135(3):407-417
An effective chromosome doubling protocol was established in essential garden crop of cucumber (Cucumis sativus L.) Cv. Hi Power. The different concentrations of colchicine (0, 250, 500, 750, and 1500 mg/L), oryzalin (0, 5, 15, 25, 50, 75, and 150 mg/L) and trifluralin (0, 5, 15, 25, 50, 75, and 150 mg/L) were applied on parthenogenesis-induced haploid nodal and shoot tip explants of cucumber for 18 and 38 h in three independent factorial experiments. Increasing concentrations of applied antimitotic agents led to the significant reduction in the survival rate of both shoot tip and nodal explants, especially in longer exposure duration. Three ploidy levels including haploid, mixoploid, and doubled haploid were regenerated form both explant types treated with colchicine, oryzalin, and trifluralin. Flow cytometry analysis proved successful chromosome doubling of haploid plants. Based on the results obtained, the highest number of regenerated doubled haploid plants (92.31%) and fruit set (86.21%) were related to immersion of nodal explants in 50 mg/L oryzalin for 18 h. The highest doubled haploid regeneration for colchicine and trifluralin antimitotic agents were 58.33 and 83.33%, respectively. The leaf size of doubled haploid plants was larger than their correspond haploids. The optimized chromosome doubling protocol would be applicable for doubled haploid production in garden crops of Cucurbitaceae family, which is recalcitrant to the spontaneous doubling, and also for in vitro polyploidy induction studies. 相似文献
11.
Rishi K. Tyagi Rajni Goswami Rajkumari Sanayaima Rakesh Singh Rajesh Tandon Anuradha Agrawal 《In vitro cellular & developmental biology. Plant》2009,45(6):721-729
Cardamom (Elettaria cardamomum Maton) has great commercial value as a spice crop in India. A one-step protocol for direct regeneration of plants and in vitro conservation by slow growth method has been developed. A maximum of 6.5 shoots/culture were obtained in 2 mo or 15.1 shoots/culture
in 4 mo on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium (MS) + 5 μM benzylaminopurine gelled with 0.7% agar (micropropagation medium). Rooting also occurred simultaneously
on the same medium. Using one shoot tip or nodal explant, about 30,375 plants can be regenerated in a year on the micropropagation
medium. In vitro conservation by slow growth method was achieved on 1/2 MS (major salts) + 5 μM BAP + 0.7% agar (conservation medium); about
70% of the cultures survived up to 18 mo at 25 ± 2°C. Successful regrowth of plants on micropropagation medium was obtained
by culturing nodal explants excised from 18-mo-old conserved plants. Some 96% of the plants survived the hardening treatment
and grew normally in a greenhouse. If 24 cultures are conserved on the conservation medium, it is possible to regenerate at
least 750 plants by using explants derived from 70% of the surviving shoots and culturing the same in micropropagation medium
for 4 mo. These plants may be used for planting or as a source of explants for the next conservation cycle. On the basis of
20 random amplified polymorphic DNA and 13 inter-simple sequence repeat primers analyses, no significant reproducible variation
was detected among the in vitro-conserved plants compared with the mother plants. 相似文献
12.
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
13.
The growth of black walnut shoot cultures was compared on media differing in nutrient formulation (MS, DKW, WPM, and 1/2X
DKW), cytokinin type (ZEA, BA, and TDZ), and cytokinin concentration. On WPM and 1/2X DKW media, hyperhydricity was observed
at frequencies of 60–100% compared with frequencies of 10–40% on the high-salt media (DKW and MS). All three cytokinins facilitated
shoot regeneration from nodal cuttings, but recurrent elongation was only observed for BA (5–12.5 μM) and ZEA (5–25 μM) with
mean shoot heights of 70–80 mm being possible after two culture periods (6–8 wk) for the fastest elongating lines. ZEA was
effective across all six shoot lines with mean shoot heights of at least 35 mm over two culture periods, but two of the shoot
lines were ‘nonresponsive’ to BA with mean shoot heights of <15 mm. In contrast, when shoot tip explants were used for culture
multiplication, ZEA was the least effective cytokinin with proliferation frequencies of only 30–40%. The proliferation frequencies
were twice as great (75–87%) for TDZ (0.05–0.1 μM), but most of the shoots regenerated were swollen or fasciated in morphology.
High rates of proliferation (61–88%) were also possible using BA (12.5–25 μM), but axillary shoots did not elongate well,
growing to heights of only 5–10 mm, on average, after 4–5 wk. Since the cytokinin types and concentrations required for high-frequency
(>50%) axillary proliferation had adverse effects on the morphology and growth potential of the shoots, multiplication strategies
based on the use of nodal cuttings are recommended. 相似文献
14.
Justicia gendarussa is a valuable medicinal plant and various parts of this plant are pharmaceutically used for the treatment of different diseases.
In vitro regeneration of shoot buds was obtained from culture of nodal cuttings as well as shoot regeneration from callus.
The nodal cuttings differed in shoot proliferation in terms of percentage of explants that responded and average shoot length
with various concentrations (4.4, 8.9, 13.3, 17.7, 22.2 μM) of 6-benzyladenine (BA), kinetin (Kn) and thidiazuron. In all
treatments, one shoot was invariably present. Optimum 87% of cultures responded with an average shoot length of 4.4 cm on
Murashige and Skoog (MS) medium supplemented with 17.7 μM BA. Callus was induced from the mature leaf segments on MS medium
supplemented with Kn (4.7, 13.9, 23.2 μM) alone or in combination with 2, 4-dichlorophenoxyacetic acid (2, 4-D; 2.3 μM, 4.5 μM).
Optimum callus induction (78%) was obtained on MS medium supplemented with 14 μM Kn and 4.5 μM 2, 4-D. When the callus was
subcultured on MS medium fortified with BA (8.9, 17.7, 26.6 μM) or Kn (9.3, 18.6, 27.9 μM) alone or in combination with α
naphthalene acetic acid (NAA; 2.7, 5.4 μM), shoot regeneration was obtained. The highest response (92%) was observed on MS
medium containing 17.7 μM BA and 5.4 μM NAA. On this medium, an average number of 12.2 shoots were obtained per responding
callus. The shoots obtained from callus and nodal cuttings were rooted with a frequency of 73% on MS medium augmented with
9.8 μM indole-3-butyric acid. The rooted shoots were successfully transplanted to soil and sand mixture (1:1) with 90% survival
rate. The protocol standardized for shoot proliferation and regeneration in J. gendarussa from nodal cuttings and leaf-derived callus is suitable for micropropagation and conservation of this essential medicinal
plant. 相似文献
15.
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
16.
Tetraploid plants were produced from leaf explants of diploid Populus pseudo-simonii by treating the leaves with colchicine. Leaf explants were cultured on MS basal medium containing 1.78 μM BA and 1.08 μM
NAA for 0, 6 and 12 days, and then transferred to the same MS liquid medium with colchicine at concentrations of 25, 50 and
75 μM for 1, 2 and 3 days. The highest efficiency of tetraploid induction was 14.6% by treating leaf explants that were pre-cultured
for 6 days and then cultured in liquid MS with 50 μM colchicine for 3 days. Flow cytometric analysis was used to screen the
tetraploids out from the regenerated plants and chromosome number counting was employed to confirm the polyploidy level. Size
and frequency of leaf stomata between diploid and tetraploid plants were demonstrated to have significant differences. 相似文献
17.
B. Vinterhalter J. Savić J. Platiša M. Raspor S. Ninković N. Mitić D. Vinterhalter 《Plant Cell, Tissue and Organ Culture》2008,94(3):299-303
Shoot cultures of nickel hyperaccumulating Alyssum murale were established from epicotyl explants of seedlings aseptically germinated on hormone-free MS medium. They were further
maintained on media with 0–0.92 μM kinetin. Optimal shoot multiplication was at 0.46 μM kinetin. Inoculation by shoot wounding
was performed with overnight suspension of A. rhizogenes A4M70GUS which contains GUS gene cointegrated in pRiA4. After 30 days hairy roots were produced at the wounding site in 31
explant (25% out of 124). Hairy roots were excised and further propagated on hormone-free medium as separate clones. In the
first passage clones 3 and 6 could be distinguished by fast growth and spontaneous shoot regeneration. In other clones (12,
23 and 25) shoot regeneration required presence of cytokinins. The five shoot culture clones regenerated from hairy roots
were further cultured on media with 0.46 μM kinetin. These shoots were characterized by good elongation and lateral shoot
branching, short internodes, minute slightly curled leaves and well developed plagiotropic root system spreading over the
surface of media. Thus all plants regenerated from hairy root cultures manifested the characteristic Ri syndrome phenotype.
They all had a strong positive GUS reaction. PCR analysis confirmed presence of uidA sequence from the gus construct. They were also tolerant to nickel accumulating up to 24,700 μg g−1 dry weight. 相似文献
18.
Pou-Ieng Hong Jen-Tsung Chen Wei-Chin Chang 《In vitro cellular & developmental biology. Plant》2010,46(3):306-311
Stem nodal segments of a sympodial orchid, Zygopetalum mackayi, were used as explants to induce protocorm-like body (PLB) formation on a hormone-free 1/2 Murashige and Skoog (1962) modified
medium (1/2MS-0) or 1/2MS supplemented with 0.045–4.54 μM 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea [TDZ] in light. After 1 mo
of culture, pale to dark green, compact and irregular nodulars of PLBs formed from the explants. For PLB induction, TDZ had
no significant effect on the percentage of PLB formation but promoted mean numbers of PLBs per responding explant at 0.045–4.54 μM.
For plant conversion, PLBs were transferred onto the same basal medium devoid of TDZ. After 2–3 mo of culture, these PLBs
successfully formed shoots and then roots with normal morphology. For PLB proliferation, TDZ has no significant effects on
the fresh weight of PLB aggregates, but there is significantly retarded shoot development at 0.45–4.54 μM after 1 mo of culture.
When transferring these PLB aggregates onto hormone-free medium for plant conversion, PLBs derived from TDZ-containing medium
showed a decrease of shoot length (0.86–2.08 cm in shoot length) compared to those derived from 1/2MS-0 (2.74 cm in shoot
length) after 1 mo of culture. Gibberellin A3 [GA3] at 0.29–8.66 μM significantly retarded PLB proliferation, but at 0.03 and 0.29 μM resulted in longer shoot length than the
control treatment. Histological studies reveal that shoot development originated from the outer region of PLB aggregates.
The young shoots initially connected to each other at their basal tissues with the parental PLBs. Plants were successfully
obtained from PLBs and then gradually became more loosely connected with each other as well as with the parental aggregates.
Several dozen plants were acclimatized in the greenhouse and showed normal morphology. 相似文献
19.
Padar (Stereospermum personatum, family Bignoniaceae) is a well-known medicinal tree. Its complete regeneration occurred through shoot bud culture in vitro. The seeds germinated
sequentially on plastic trays and polyethylene bags for 21 days served as explants source. Nodal segments from the seedlings
were established on MS medium supplemented with 4.44 μM BA, in which 86.6% nodes showed shoot bud elongation. Then, nodal
segments from the developed shoots were cultured on MS medium with several BA concentrations; best shoot multiplication was
obtained with 0.44 μM BA. In a second experiment where PVP was added to proliferation medium, nodal segments from developed
shoots produced maximum 2.78 shoots per node. The nodal segments showed shoot multiplication up to seventh subculture on.
Finally, shoots were rooted on MS medium with 2.46 μM IBA. The plants transferred to net pots containing coco-peat were acclimatized
in green house, where more than 80% plants survived and grew normally. 相似文献
20.
S. Antony Ceasar S. Ignacimuthu 《In vitro cellular & developmental biology. Plant》2008,44(5):427-435
An efficient somatic embryogenesis and plant regeneration system was developed from shoot apex explants of finger millet,
Eleusine coracana. Eight genotypes, CO 7, CO 9, CO 13, CO 14, GPU 26, GPU 28, GPU 45, and GPU 48, were assessed in this study. The maximum
somatic embryogenic induction, at 98.6%, was obtained from explants cultured on Murashige and Skoog medium supplemented with
18.0 μM dichlorophenoxyacetic acid and 2.3 μM kinetin. The highest number of shoot induction (26) was observed after transfer
of embryonic callus to regeneration medium supplemented with 4.5 μM thidiazuran and 4.6 μM kinetin. Significant differences
were observed between genotypes for somatic embryogenesis and plant regeneration. GPU 45 gave the best response, while CO
7 was the least responsive under the culture conditions tested in this study. Regenerated plants were successfully rooted
and grown to maturity after hardening in soil. 相似文献