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1.
An efficient protocol was developed for micropropagation of an economically important timber-yielding multipurpose tree, Pterocarpus marsupium Roxb. Multiple shoots were induced from cotyledonary nodes (CNs) derived from 18-d-old axenic seedlings on Murashige and
Skoog (MS) medium supplemented with thidiazuron (TDZ) (0.1–10 μM). The highest shoot regeneration frequency (90%) and maximum
number (15.2 ± 0.20) of shoots per explant was recorded on MS medium amended with 0.4 μM TDZ. Continuous presence of TDZ inhibited
shoot elongation. In the primary medium, TDZ-initiated cultures were transferred to the secondary medium supplemented with
another cytokinin, 6-benzyladenine (BA), for shoot growth and elongation. Maximum (90%) shoot elongation with an average shoot
length of 5.4 ± 0.06 cm was observed at 5 μM BA. To further enhance the number of shoots per explant, mother tissue was repeatedly
subcultured on fresh shoot induction medium after each harvest of newly formed shoots. Thus, by adopting this strategy, an
average of 44 shoots per explant could be obtained. About 65% of in vitro regenerated shoots produced a maximum number (4.4 ± 0.2) of roots per shoot by a two-step culture procedure employing pulse
treatment and subsequent transfer of treated shoots to a low concentration of 0.2 μM indole-3-butyric acid along with phloroglucinol
(3.96 μM). The in vitro-raised plantlets were successfully acclimatized first under culture room conditions, then to greenhouse with 70% survival
rate. 相似文献
2.
Brassinosteroids (BRs) have been proposed to increase the resistance of plants to drought stress. The effect of foliar application
of 0.1 μM 24-epibrassinolide (EBR) on chlorophyll (Chl) content, photosystem 2 (PS 2) photochemistry, membrane permeability,
lipid peroxidation, relative water content (RWC), proline content, and the antioxidant system in drought-stressed Chorispora bungeana plants was investigated. The results showed that polyethylene glycol (PEG) induced water stress decreased RWC, Chl content
and variable to maximum Chl fluorescence ratio (Fv/Fm) less in plants pretreated with EBR than in non-pretreated plants. In addition, lipid peroxidation, measured in terms of
malondialdehyde content, membrane permeability and proline content in drought-stressed plants were less increased in EBR pretreated
plants, while antioxidative enzyme activities and reduced ascorbate and glutathione contents were more increased in EBR pretreated
than in non-pretreated plants. These results suggested that EBR could improve plant growth under drought stress 相似文献
3.
The effects of UVB on the kinetics of stem elongation of wild type (WT) and photomorphogenic mutants of tomato were studied
by using linear voltage transducers connected to a computer. Twenty-one or twenty-six-day-old plants, grown in 12 h white
light (150 μmol m−2 s−1 PAR)/12 h dark cycles, were first transferred to 200 μmol m−2 s−1 monochromatic yellow light for 12 h, then irradiated with 0.1 or 4.5 μmol m−2 s−1 UVB for 12 h and finally kept in darkness for another 24 h. The measurements of the kinetics of stem elongation started after
4 h under yellow light. Significant differences in stem growth during the irradiation with yellow light, as well as during
the dark period, were found between the genotypes. In darkness, the magnitude of stem growth followed the order: tri > AC = fri > MMau > hp1. Two factors determined the large differences of growth in darkness: 1) the different stem elongation rate (SER) and 2) the
different duration of the growing phase among the genotypes. In darkness the stem growth of au and hp1 mutants lasted for about 18 h, whereas it continued for the whole experimental period (36 h) in the other genotypes. UVB
irradiation substantially reduced elongation growth of all genotypes (4.5 μmol m−2 s−1 being more effective than 0.1 μmol m−2 s−1). Both fluence rates of UVB induced a detectable reduction of SER already after 15 min of irradiation. Red light inhibited,
while far red light promoted stem growth of all the genotypes tested. fri (phyA null), tri (phyB1 null), hp1 (exhibiting exaggerated phytochrome responses) mutants and WT tomato showed similar levels of UVB–induced inhibition of growth,
while the aurea mutant showed the largest growth inhibition during the 12 h of irradiation. These results indicate that phytochrome is not
directly involved in UVB control of stem elongation. The results of dichromatic irradiations UVB + red or UVB + far red indicate
the presence of distinct and additive action of UVB photoreceptor and of the phytochrome system in the photoregulation of
stem growth.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
4.
Tubers can be initiated and developed in vitro from nodal cuttings of yam (Dioscorea cayenensis-D. rotundata complex). The effect of exogenous jasmonic acid, alone or in combination with putrescine, on these processes was investigated in
relationship to endogenous jasmonic acid and polyamine levels. Application of exogenous jasmonic acid at various concentrations
positively affected microtuber formation and growth from yam nodal cuttings. In control conditions, 3 weeks were needed to
obtain 100% of tuberisation. Jasmonic acid at low level (0.1 μM) accelerated tuber formation (46% after 1 week) as did putrescine
(10 μM). But endogenous levels of jasmonic acid were not significantly affected by its exogenous presence in the medium. Jasmonic
acid also interacted with other growth regulators as polyamines, but the decrease in time necessary to observe tuber formation
could not be correlated with endogenous modifications of PUT content. The presence of jasmonic acid (0.1–1 μM) as PUT (1 μM)
induced also an increase of tuber length and weight. The combination of jasmonic acid (0.1 μM) and putrescine (1 μM) had no
positive effect on tuber formation (precocity) but had an additive effect on further growth (length and weight). In the future,
these results could help the optimising in vitro conditions for mass production of larger yam microtubers. 相似文献
5.
Jin Cui Jianjun Chen Richard J. Henny 《In vitro cellular & developmental biology. Plant》2009,45(1):34-43
Plant regeneration through direct somatic embryogenesis in Aeschynanthus radicans ‘Mona Lisa’ was achieved in this study. Globular somatic embryos were formed directly from cut edges of leaf explants and
cut ends or on the surface of stem explants 4 wk after culture on Murashige and Skoog (MS) medium supplemented with N-phenyl-N′-1, 2, 3-thiadiazol-5-ylurea (TDZ) with α-naphthalene acetic acid (NAA), TDZ with 2,4-dichlorophenoxyacetic acid (2,4-D),
or 6-benzylaminopurine (BA) or kintin (KN) with 2,4-D. MS medium containing 9.08 μM TDZ and 2.68 μM 2,4-D resulted in 71%
of stem explants producing somatic embryos. In contrast, 40% of leaf explants produced somatic embryos when induced in medium
containing 6.81 μM TDZ and 2.68 μM 2,4-D. Somatic embryos matured, and some germinated into small plants on the initial induction
medium. Up to 64% of stem explants cultured on medium supplemented with 9.08 μM TDZ + 2.68 μM 2,4-D, 36% of leaf explants
cultured on medium containing 6.81 μM TDZ and 2.68 μM 2,4-D had somatic embryo germination before or after transferring onto
MS medium containing 8.88 μM BA and 1.07 μM NAA. Shoots elongated better and roots developed well on MS medium without growth
regulators. Approximately 30–50 plantlets were regenerated from each stem or leaf explant. The regenerated plants grew vigorously
after transplanting to a soil-less substrate in a shaded greenhouse with more than a 98% survival rate. Three months after
their establishment in the shaded greenhouse, 500 plants regenerated from stem explants were morphologically evaluated, from
which five types of variants that had large, orbicular, elliptic, small, and lanceolate leaves were identified. Flow cytometry
analysis of the variants along with the parent showed that they all had one identical peak, indicating that the variant lines,
like the parent, were diploid. The mean nuclear DNA contents of the variant lines and their parent ranged from 4.90 to 4.99 pg
2C−1, which were not significantly different statistically. The results suggest that the regenerated plants have a stable ploidy
level, and the regeneration method established in this study can be used for rapid propagation of ploidy-stable Aeschynanthus radicans. 相似文献
6.
Murugesan Dhandapani Seung-Beom Hong Channa Reddy Aswath Doo Hwan Kim 《In vitro cellular & developmental biology. Plant》2008,44(1):8-13
We have optimized conditions for efficient regeneration of the vegetatively propagated zoysia grass (Zoysia matrella L. Merr) cultivar “Konhee”. Two explants, young inflorescences, and stem nodes, were used and they displayed different responses
to combinations and concentrations of plant growth regulators in callusing, embryogenic callus formation, and regeneration.
The highest callus initiation rate from young inflorescences was obtained on medium supplemented with 4.5 to 9.0 μM 2,4-dicholorophenoxy
acetic acid (2,4-D) and 0.44 μM 6-benzyl amino purine (BA). When the BA concentration was lowered to 0.044 μM, the highest
percent embryogenic callus induction from young inflorescences was achieved. The highest callus initiation rate from stem
nodes was obtained, when young inflorescences were cultured on MS medium supplemented with 4.5 to 9.0 μM 2,4-D, 0.44 μM BA,
and 0.037 μM abscisic acid (ABA). But embryogenic callus formation from the stem node was highest in the presence of 4.5 to
9.0 μM 2,4-D, 0.044 μM BA, and 0.037 μM ABA. Addition of ABA significantly increased embryogenic callus formation from stem
nodes, but not from young inflorescences. Regeneration percentage was variable in response to BA level, and inclusion of α-naphthalene
acetic acid (NAA) and gibberellic acid (GA3) further increased the regeneration percentage. The highest regeneration percentages obtained from the young inflorescences
and stem nodes were 82% and 67%, respectively. This is the first report showing that plants can be regenerated from young
inflorescences and stem nodes of vegetatively propagated zoysia grass. 相似文献
7.
Factors affecting successful establishment in vitro, rapid proliferation and rooting of apricot cultivar ‘Bebecou’ were studied. Ethanol and NaOCl were applied in several combinations for disinfection; chilling, plant growth regulators BA, IAA and GA3, antibiotics, different culture vessels and systems of subculture were evaluated for the optimization of shoot proliferation and the auxins NAA and IBA were assessed for root induction. The highest number of new microshoots/explant (18.7) was obtained in a culture medium supplemented with 2.2 μM BA+0.57 μM IAA after 300 h of chilling. The effect of GA3 (11.4 μM) on shoot proliferation was positive in combination with 4.4 or 8.9 μM BA. Shoot length and productivity were highest at 2.2 μM BA+11.4 μM GA3+0.57 μM IAA and at 2.2 μM BA+0.57 μM IAA, respectively and decreased as cytokinin concentration increased. The antibiotic ‘Na-cefotaxime’ had a minimal impact on shoot growth when used at the lowest concentration (250 mg l−1). Subculture every 2 weeks in a medium supplemented with 2.2 μM BA and 0.57 μM IAA was more efficient for shoot induction than alternation of 20 days culture in a propagation medium supplemented with 2.2 μM BA and 10 days culture in an elongation medium supplemented with 1.1 μM BA and 5.71 μM IAA. The highest number of roots/shoot (8.1) was recorded at 19.6 μM IBA. 相似文献
8.
Takateru Ishimori Yoshiji Niimi Dong-Sheng Han 《Plant Cell, Tissue and Organ Culture》2007,88(3):313-318
Scales excised from lily bulblets were cultured on MS medium supplemented with 0.044 or 4.4 μM BA in the dark for 180 days.
The culture period was divided into stage 1 (day 0–30), stage 2 (day 31–90) and stage 3 (day 91–180). The scales were cultured
at 25°C in stage 1, 25°C or 8°C in stage 2, and 25°C in stage 3. When the scales were cultured on medium with 4.4 μM BA at
25°C for 180 days, bulblets with and without an elongated stem were produced. The percentage of bulblets with elongated stems
greatly increased when the scales had been cultured at 8°C in stage 2. On medium with 0.044 μM BA, only bulblets without elongated
stems were produced. The diameter of shoot primodia significantly enlarged in bulblets produced on medium with 4.4 μM BA at
8°C in stage 2 and no such enlargement occurred under the other conditions. Nearly square parenchyma cells were observed in
the non-elongated shoot primodia in the former bulblets but not in the latter. These cells changed into longitudinally rectangular
ones in the internode of elongated stems. Procambium was arranged almost parallel to the shoot axis in the stem of bulblets
in the medium with 4.4 μM BA, but not in the medium with 0.044 μM BA. 相似文献
9.
Micropropagation of juvenile sycamore maple via adventitious shoot formation by use of thidiazuron 总被引:4,自引:0,他引:4
Eva Wilhelm 《Plant Cell, Tissue and Organ Culture》1999,57(1):57-60
Zygotic embryos of sycamore maple (Acer pseudoplatanus) were dissected into plumule, hypocotyl and radicle sections. The segments
were placed on MS medium containing 1 μM 6-benzyladenine (BA) and/or 0.02 μM to 0.1 μM thidiazuron (TDZ). Hypocotyl and plumule
explants produced callus, adventitious buds and shoots with increasing plant growth regulator concentrations. Hypocotyls produced
more, but smaller shoots compared to plumule segments. Subculturing excised shoots and calluses on Murashige and Skoog (MS)
media with 1 μM BA and/or 0.04 μM TDZ led to continuous production of shoots. The best proliferation capacity occurred with
0.04 μM TDZ and 1.0 μM BA, both shoots and calluses. This combination showed a stimulatory effect also on length of newly
formed shoots. Calluses performed generally better compared to shoot explants independent of growth regulator treatment. Excised
shoots 2 to 3-cm-long were successfully rooted on MS media either with or without growth regulators (123 μM IBA pulse) followed
by transfer to the greenhouse.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
The effect of copper sulphate on differentiation and elongation of shoot buds from cotyledonary explants of Capsicum annuum L. cv X-235 was investigated. Shoot buds were induced on medium supplemented with 22.2 μM BAP and 14.7 μM PAA. Elongation
of shoot buds was obtained on MS medium containing 13.3 μM BAP + 0.58 μM GA3. Both shoot induction and elongation media were supplemented with different levels of CuSO4 (0–5 μM). The levels of CuSO4 in the induction as well as elongation medium highly influenced the shoot bud formation and their subsequent elongation.
Highest number of shoot buds per explant was obtained when the concentration of CuSO4 was increased 30 times to the normal MS level. Shoot buds formation frequency i.e., the number of shoots formed per explant
was increased two fold as compared to those formed on control. Elongation both in terms of percentage and length of shoots
was better than that on control. Healthy elongated shoots were rooted on MS medium supplemented with 5.7 μM IAA. Rooted plantlets
were transferred to field conditions. 相似文献
11.
María del Socorro Santos Díaz Candy Carranza Álvarez 《In vitro cellular & developmental biology. Plant》2009,45(2):162-170
Two procedures for the in vitro propagation of Encyclia mariae, a threatened Mexican orchid, were developed. In the first procedure, leaves from in vitro germinated seedlings were cultured on Murashige and Skoog medium (MS) supplemented with the range of 2.21–4.4 μM 6-benzylaminopurine
(BA) in combination with 2.69–10.74 μM naphthalene acetic (NAA), 2.07–8.29 μM indole-3-butyric (IBA), or 2.85–11.42 μM indole-3-acetic
acid (IAA) to determine the best medium for the induction of shooting. Maximum direct shoot formation from leaves was observed
on MS containing 22.21 μM BA and 10.74 μM NAA (25 shoots/explant). The second procedure began with the culture of protocorms
on media containing NAA, IBA, or IAA, which induced callus formation with high regenerative potential in the form of protocorm-like-bodies
(PLBs) that eventually differentiated into shoots. The optimal response was attained when these structures were cultured on
medium with 4.14 μM IBA (30 shoots/PLB). To promote the elongation of shoots derived from PLBs, the material was subcultured
onto MS medium containing 22.21 μM BA and 5.37 μM NAA. Through the exploration of the effects of auxins and matrix on the
rooting of shoots, it was determined that the optimal rooting occurred on media supplemented either with 5.71 μM IAA or 4.14 μM
IBA either on agar-gelled medium or in liquid media with coir as the matrix. Rooting was found to be 20% higher in liquid
media than in agar-gelled medium. 相似文献
12.
Joshua Otieno Ogweno Wen Hai Hu Xing Shun Song Kai Shi Wei Hua Mao Yan Hong Zhou Jing Quan Yu 《Plant Growth Regulation》2010,60(3):175-182
Detached leaves of tomato (Lycopersicon esculentum Mill.) experienced photoinhibition associated with sharp reductions in net photosynthetic rate (Pn), quantum efficiency of
PSII (ΦPSII) and photochemical quenching (qP) even though they were exposed to mild light intensity (400 μmol m−2 s−1 PPFD) at 28°C. Photoinhibition and the reduction in Pn, ΦPSII and qP, however, were significantly alleviated by 1 mg l−1 ABA, 0.1 mg l−1
N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) and 0.01 mg l−1 24-epibrassinolide (EBR). Higher concentrations, however, reduced the effects or even exacerbated the occurrence of photoinhibition.
Superoxide dismutase and ascorbate peroxidase activity in leaves increased with the increases in ABA concentration within
1–100 mg l−1, CPPU concentration within 0.1–10 mg l−1 and EBR concentration within 0.01–1.0 mg l−1. Catalase and guaiacol peroxidase activity also increased with the increase in EBR concentration but CPPU and ABA treatments
at higher concentrations caused a decrease. Malondialdehyde (MDA) content decreased with the increase in CPPU concentration.
ABA and EBR, however, decreased MDA concentration only at 1 and 0.01 mg l−1, respectively. In conclusion, detached leaves had increased sensitivity to PSII photoinhibition. Photoinhibition-induced
decrease in photosynthesis, however, was significantly alleviated by EBR, CPPU and ABA at a proper concentration. 相似文献
13.
In the present study, the procedures for induction of somatic embryogenesis (SE) in an in vitro culture of the tulip have been developed. SE was initiated on flower stem explants isolated from “Apeldoorn” bulbs during
their low-temperature treatment. Bulbs had not been chilled or had been chilled for 12 or 24 weeks at 5°C. The explants were
cultured with exogenous auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (Picloram), α-naphthaleneacetic
acid (NAA) at 1–100 μM and cytokinins: benzyladenine (BA) and zeatin (ZEA) at 0.5–50 μM. Increase in auxin concentrations
caused an intensive enlargement of the explant parenchyma, which changed into homogenous colorless callus. On the same media,
vein bundles developed into yellowish, nodular callus. Picloram was more efficient in inducing the formation of embryogenic
nodular callus than 2,4-D, whereas the latter stimulated formation of colorless callus. The base of the lower part of the
flower stem isolated from bulbs chilled for 12 weeks proved to be the best explant for callus formation. The highest number
of somatic embryos was produced on medium with 25 μM Picloram and 0.5 μM BA. Development of adventitious roots was noticed
in the presence of 2,4-D. Globular embryos developed into torpedo stage embryos under the influence of BA (5 μM) and NAA (0.5 μM).
Morphological and anatomical data describing development of callus and somatic embryos are presented. 相似文献
14.
A simple, high frequency, and reproducible method for plant regeneration through direct organogenesis from cotyledonary leaf
explants of Jatropha curcas was developed using Murashige and Skoog (MS) medium supplemented with different concentrations of thidiazuron (TDZ) or 6-benzyl
aminopurine (BAP). Medium containing TDZ has greater influence on regeneration as compared to BAP. The induced shoot buds
were transferred to MS medium containing 10 μM kinetin (Kn), 4.5 μM BAP, and 5.5 μM α-naphthaleneacetic acid (NAA) for shoot
proliferation. The proliferated shoots could be elongated on MS medium supplemented with different concentrations and combinations
of BAP, indole-3-acetic acid (IAA), NAA, and indole-3-butyric acid (IBA). MS medium with 2.25 μM BAP and 8.5 μM IAA was found
to be the best combination for shoot elongation. However, significant differences in plant regeneration and shoot elongation
were observed among the genotypes studied. Rooting was achieved when the basal cut end of elongated shoots were dipped in
half strength MS liquid medium containing different concentrations and combinations of IBA, IAA, and NAA for 4 days, followed
by transfer to growth regulators free half strength MS medium supplemented 0.25 mg l−1 activated charcoal. Elongated shoot treated with 15 μM IBA, 5.7 μM IAA, and 11 μM NAA resulted in highest percent rooting.
The rooted plants could be established in soil with more than 90% survival rate. The method developed may be useful in improvement
of J. curcas through genetic modification. 相似文献
15.
Andrea Ferrigno Cesarina Gregotti Plinio Richelmi Mariapia Vairetti 《In vitro cellular & developmental biology. Animal》2010,46(5):445-449
In the present study, the effects of dexamethasone on cadmium-induced toxicity were evaluated in isolated rat hepatocytes.
Hepatocytes were cultured for 24 h in William’s E medium containing fetal calf serum (10%), insulin (0.1 IU/ml), and glucagon
(0.01 μM) in the absence or presence of 0.1 μM dexamethasone. Cadmium chloride, 5 or 10 μM, was added to the medium and the
toxicity was evaluated for up to 48 h after treatment. Lactate dehydrogenase (LDH) release, the reduced and oxidized glutathione
ratio (GSH/GSSG), protein-SH groups, and lipid peroxidation levels were evaluated. Cadmium induced a dose- and time-dependent
LDH release in control hepatocytes at 24 h (Cd 10 μM 42%) while hepatocytes pretreated with dexamethasone showed lower necrosis
(Cd 10 μM 12% at 24 h). GSH/GSSH ratio and protein-SH groups were higher while lipid peroxidation was lower in dexamethasone-treated
hepatocytes as compared with untreated cells. In conclusion, cadmium toxicity was associated with an increase in intracellular
oxidative stress responsible for accelerated cell death. The use of dexamethasone prevented cadmium damage, suggesting that
the cytoprotective action of this hormone is related to its effect in preventing changes in thiols such as glutathione and
protein-SH groups. 相似文献
16.
Kaitlin J. Palla Paula M. Pijut 《In vitro cellular & developmental biology. Plant》2011,47(2):250-256
A plant regeneration protocol was developed for white ash (Fraxinus americana L.). Hypocotyls and cotyledons excised from embryos were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine
(BA) plus thidiazuron (TDZ), and compared for organogenic potential. Sixty-six percent of hypocotyl segments and 10.4% of
cotyledon segments produced adventitious shoots, with a mean number of adventitious shoots per explant of 3.5 ± 0.9 and 2.5 ± 1.5,
respectively. The best regeneration medium (52% shoot formation; 47% shoot elongation) for hypocotyls was MS basal medium
containing 22.2 μM BA plus 0.5 μM TDZ, producing a mean of 3.9 ± 0.4 adventitious shoots. Adventitious shoots were established
as proliferating shoot cultures following transfer to MS medium with Gamborg B5 vitamins supplemented with 10 μM BA plus 10 μM
TDZ. For in vitro rooting, woody plant medium with indole-3-acetic acid (IAA) at 0, 2.9, 5.7, or 8.6 μM in combination with 4.9 μM indole-3-butyric
acid (IBA) was tested for a 5- or 10-d dark culture period, followed by culture under a 16-h photoperiod. The best rooting
(78% to 81%) of in vitro shoots was obtained with a 5 d dark culture treatment on medium containing 2.9 or 5.7 μM IAA plus 4.9 μM IBA, with an average
of 2.6 ± 0.4 roots per shoot. Rooted plants were successfully acclimatized to the greenhouse. This adventitious shoot regeneration
and rooting protocol will be used as the basis for experimental studies to produce transgenic white ash with resistance to
the emerald ash borer. 相似文献
17.
Vengadesan G. Ganapathi A. Prem Anand R. Ramesh Anbazhagan V. 《Plant Cell, Tissue and Organ Culture》2000,61(1):23-28
In vitro morphogenesis via organogenesis was achieved from callus cultures derived from hypocotyl explants of Acacia sinuata on MS (Murashige and Skoog, 1962) medium. Calli were induced from hypocotyl explants excised from 7-day-old seedlings on
MS medium containing 3% sucrose, 0.8% agar, 6.78 μM 2,4-dichlorophenoxyacetic acid and 2.22 μM 6-benzylaminopurine. Regeneration
of adventitious buds from callus was achieved when they were cultured on MS medium supplemented with 10% coconut water, 13.2
μM 6-benzylaminopurine and 3.42 μM indoleacetic acid. Addition of gibberellic acid (1.73 μM) favored shoot elongation. Regenerated
shoots produced prominent roots when transferred to half strength MS medium supplemented with 7.36 μM indolebutyric acid.
Rooted plantlets, thus developed were hardened and successfully established in the soil. This protocol yielded an average
of 20 plants per hypocotyl explant over a period of 4 months.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
Caulogenic responses of various explant types from 12-month-old plants of Hemidesmus indicus were tested. Second and third visible nodes (0.5 cm) from the apex and root segments (0.5 cm) were the most and least regenerative
respectively, with the formation of 9.37 and 2.6 shoots in 4 weeks on half strength MS medium supplemented with 2.22 μM BA
and 1.07 μM NAA and 4.44 μM BA and 2.69 μM NAA respectively. Caulogenic ability of the nodes decreased with increasing maturity.
Shoot buds initiated upon the young nodes on day 10 developed into 7.2 cm long shoots within 4 weeks thereby making a shoot
elongation phase unnecessary. Nodal explants of the in vitro raised shoots subcultured in the same medium produced 9.32 shoots of 7.1 cm length in 3–4 weeks, similar to those of the
mature plant-derived nodes. Multiplication through subculture of the nodes up to 25 passages of 4 weeks each was achieved
without decline. Shoot cultures were rooted in quarter salt strength MS medium containing 9.8 μM IBA and the rooted plants
were hardened for establishment in pots at 96% rate. Four months after establishment, the micropropagated plants were stable
and showed uniform morphological and growth characteristic. After 12 months of cultivation in the field, on an average micropropagated
plant consisted of 4–5 shoots, 5–8 branches per shoot and increased root biomass (13.5 g) compared to the poor growth (single
shoot and 2–3 branches) and root production (4.6 g) values obtained with plants raised from conventional rooted stem cuttings.
The concentration of the root specific compound, 2-hydroxy 4-methoxy benzaldehyde per plant was 2–3 fold higher in micropropagated
plants though on unit dry root biomass (0.12% per g dry wt) basis it remained the same between two sources of plants.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
B. Wang D. X. Peng Z. X. Sun N. Zhang S. M. Gao 《In vitro cellular & developmental biology. Plant》2008,44(2):105-111
Ramie [Boehmeria nivea (L.) Gaud] is one of the most important perennial fiber crops in China. In vitro tissue culture of ramie could serve as an important means for its improvement through genetic transformation. To improve
the regeneration capacity of ramie, the effects on plant regeneration of donor plant age, basal medium, plant growth regulators,
and culture conditions were evaluated using explants derived from the cotyledon, hypocotyl, leaf, petiole, and stem of ramie
seedlings. Cotyledons and hypocotyls excised from 4-d-old seedlings and leaves and petioles and stems from 15-d-old seedlings
were optimal explants. The highest regeneration efficiency was obtained on Murashige and Skoog salts with Gamborg’s B5 vitamins basal medium containing 2.27 μM thidiazuron (TDZ) and 0.054 μM naphthaleneacetic acid (NAA) for the five explant
types tested. A photoperiod of 16:8 h (light/dark) was found to be superior than continuous darkness for regeneration of ramie
using TDZ. The regenerated shoots were transferred to hormone-free medium for shoot elongation and successfully rooted on
half-strength Murashige and Skoog supplemented with 0.134 μM NAA. The rooted plantlets with four to five leaves were transplanted
to greenhouse for further growth. 相似文献
20.
Adventitious bud formation in Alhagi graecorum 总被引:1,自引:0,他引:1
Various parts of seedlings and in vitro propagated shoots of Alhagi graecorum Boiss were cultured on different media with different 6-benzyladenine (BA) and kinetin (KIN) concentrations to compare their
potential to regenerate shoots. Murashige and Skoog (MS) medium with 2.5 μM BA and hypocotyl gave the best results. Callus
was obtained from stem segments on MS medium supplemented with 2.5 μM BA, 5 μM 1-naphthaleneacetic acid (NAA) and 0.5 μM 2,4-dichlorophenoxyacetic
acid (2,4-D). Shoot formation from callus occurred upon its transfer to MS medium supplemented with 2.5 μM BA. Mature explants which
showed a relatively low potential for adventitious buds or callus formation, regenerated shoots abundantly using the tiny-mature-explant
method. The regenerated shoots were rooted on half strength MS medium supplemented with 5 μM 3-indolebutyric acid (IBA).
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献