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1.
Prolific shoot regeneration via organogenesis was induced from leaf and leaf petiole explants of the endemic Astragalus cariensis species on Murashige and Skoog (MS) medium with α-naphthaleneacetic acid (NAA) and benzyladenine (BA) within 8 week. The
highest number of shoots (23/explants) was obtained from leaf explants cultured on MS with 0.5 mg/l NAA and 4 mg/l BA. Elongated
shoots were successfully rooted in MS medium with 0.5 mg/l indole-3-butyric acid. Rooted plantlets were acclimatized in pots
containing 1:1 mixture of peat and perlite. 相似文献
2.
This study investigated the induction and in vitro alkaloid yield of calluses and protocorm-like bodies (PLBs) from Pinellia ternata (Thunb.) Berit (Araceae). We planned to use this material in future studies related to the mass production of medicinally valuable compounds and regulation of alkaloid metabolism. Different combinations of 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzyladenine (6-BA), kinetin (Kin), and α-naphthaleneacetic acid (NAA) were used to induce callus and PLB formation from P. ternata tuber explants. The results showed that three physiologically distinct calluses were induced by different combinations of 2,4-D, 6-BA, and Kin used in this study. The calluses differed in color, texture, differentiation status, and alkaloid content. The alkaloid content of the three calli types ranged from 0.0175% to 0.0293%. In comparison, the alkaloid content of field-grown tubers was 0.0072%. Many reports have indicated that 2,4-D suppresses the biosynthesis of secondary metabolites; however, our results show that 2,4-D promoted alkaloid production in Pinellia calluses. The combination of NAA?+?6-BA induced PLB formation. The PLB alkaloid content of 0.0321% was 1.1 to 1.8 times higher than the alkaloid content of the calluses and 4.5 times higher than the field-grown tubers. In conclusion, the induction of calluses and PLBs with alkaloid content greater than that of field-grown tubers indicates the potential use of these tissue culture materials for bioprocessing alkaloids from P. ternata and for the study of alkaloid metabolism. 相似文献
3.
Protocorm-like bodies (PLBs) were induced from shoot tips of Grammatophyllum speciosum, a Thai orchid. The highest frequency of PLBs (93%) were observed on explants incubated on 1/2-Murashige and Skoog (MS) liquid
medium containing 2% (w/v) sucrose without any plant growth regulators (PGRs). Tests with different carbon sources compared
to sucrose revealed that maltose promoted the highest relative growth of G. speciosum PLBs (7-fold increase), while trehalose and sucrose yielded 5-fold and 4-fold increases, respectively. In 1/2 MS liquid medium,
addition of 15 mg/l of chitosan promoted a 7-fold increase in PLB growth while 25 mg/l promoted a 4-fold increase. However,
the relative growth rate in solid culture was significantly lower than that in liquid culture. In addition, chitosan supplementation
in solid medium promoted shoot formation but not rooting. Plantlet regeneration was induced using a combination of NAA and
BA supplementation in 1/2 MS solid medium with optimum induction shoot and root formation at 2.0 mg/l NAA and 1.0 mg/l BA.
Using this protocol, approximately 8 months was required to obtain a hundred plantlets from one shoot tip. The plantlets showed
no changes in ploidy when tested by flow cytometry. 相似文献
4.
A simple and efficient procedure was developed for in vitro propagation of Solanum aculeatissimum Jacq. using leaf and petiole explants cultured on Murashige and Skoog (MS) medium supplemented with α-naphthalene acetic
acid (NAA) and 6-benzyladenine (BA). Effects of various plant growth regulators, explant types, carbohydrates, and basal salts
on induction of adventitious shoots were also studied. Leaf explants appeared to have better regeneration capacity than petiole
explants in the tested media. The highest regeneration frequency (79.33 ± 3.60%) and shoot number (11.33 ± 2.21 shoots per
explant) were obtained in leaf explants in MS medium containing 3% sucrose and 0.8% agar, supplemented with 0.1 mg/l NAA and
2.0 mg/l BA, whereas petiole explants were more responsive to 0.1 mg/l NAA and 1.0 mg/l thiadiazuron. Developed shoots rooted
best on MS medium with 1.0 mg/l indole acetic acid (IAA), producing 18.33 ± 2.51 roots per shoot. Histological investigation
showed that the shoot buds originated mainly from epidermal cells of wounded tissues, without callus formation. The regenerated
plantlets were successfully acclimatized in a greenhouse, where over 90% developed into morphologically normal and fertile
plants. Results of flow cytometry analysis on S. aculeatissimum indicated no variation in the ploidy levels of plants regenerated via direct shoot formation and showed almost the same phenotype
as that of mother plants. This adventitious shoot regeneration method may be used for large-scale shoot propagation and genetic
engineering studies of S. aculeatissimum. 相似文献
5.
An indirect in vitro plant regeneration protocol for Vanilla planifolia has been established. Juvenile leaf and nodal segments from V. planifolia were used as explants to initiate callus. Nodal explants showed better callus initiation than juvenile leaf explants, with
35.0% of explants forming callus when cultured on Murashige and Skoog (MS) basal medium supplemented with 2.0 mg/l 1-naphthylacetic
acid (NAA) and 1.0 mg/l 6-benzyladenine (BA). Almost 10.0% of juvenile leaf explants were induced to form callus on the MS
basal medium containing 2.0 mg/l NAA and 2.0 mg/l BA, whereas no callus formed in the presence of any concentrations of 2,4-dichlorophenoxyacetic
acid (2,4-D) and BA. After 8 weeks, callus generated was transferred to MS basal medium containing 1.0 mg/l BA and 0.5 mg/l
NAA. A mean number of 4.2 shoots per callus was produced on this medium, with a mean length of 3.8 cm after 8 weeks of culture.
Roots formed on 88.3% of plantlets when they were cultured on MS medium supplemented with 1.0 mg/l NAA, with a mean length
of 4.4 cm after 4 weeks of culture. Of the rooted plantlets, 90.0% survived acclimatisation and were making new growth after
4 weeks. 相似文献
6.
Adventitious buds or protocorm-like bodies were regenerated directly from excised explants without intervening callus. Differences in the ability of regeneration were observed among different plant organs with bulbils showing the highest regenerative ability followed by leaf blade and petiole. Ability of vegetative propagation of bulbil could be maintained by alternate solid-and liquid-medium culture. Theoretically, 1.7×10 27 plantlets could be produced from a single bulbil by this technique within one year based on the production and rapid growth of protocorm-like bodies and adventitious buds. Concentration of MS salts, NAA and sucrose influenced not only root formation from the differentiated adventitious buds, but also root number and length. For root formation, the best combination was one-half strength MS salts with 3–5% sucrose and 1 mg/l NAA. The high survival rate of 96% was recorded when plantlets were transplanted into a mixture of vermiculite:loam soil:peat moss (1:2:1). Plants from in vitro culture were morphological similar to field-grown plants. The acute toxicity of crude extracts from protocorm-like bodies was about one-fourth that of extracts from tubers of field-grown plants when tested with white mice. Tissue culture has potential for clonal propagation of Pinellia ternata plants for commercial use.Abbreviations MS
Murashige and Skoog (1962)
- 2,4-D
2,4-dichlorophenoxyacetic acid
- NAA
-naphthaleneacetic acid
- BA
6-benzylaminopurine 相似文献
7.
The effects of a two-stage pretreatment of seedlings on the subsequent shoot regeneration capacity were investigated. Pretreated
seedlings were obtained by germinating seeds on three different germination media and then further culturing on six different growth media. Lamina and petiole explants of two sugar beet ( Beta
vulgaris L.) breeding lines were then excised from the pretreated seedlings and cultured on five different shoot regeneration media. In both breeding lines, petiole explants produced significantly more shoots than lamina explants with higher frequencies
of organogenic capacities; petiole explants of the lines M1195 and ELK345 produced a mean of 2.1 and 2.7 shoots per explant
while their lamina explants produced 1.5 and 2.2 shoots per explant, respectively. A genotypic variation was evident as the
line ELK345 was more productive for shoot development from both types of explants. In overall comparisons of different germination, growth and regeneration media, germination medium was most effective when supplemented with 0.5 mg/l 6-benzyladenine (BA) while both growth and regeneration
media were most productive when contained a combination of 0.25 mg/l BA and 0.10 mg/l indole-3-butyric acid (IBA). Of all
the treatments tested, the highest mean number of shoots per explant (8.3 shoots) and frequency of organogenic explants (75.6%)
were obtained on regeneration medium supplemented with 0.25 mg/l BA and 0.10 mg/l IBA when petiole explants of the line ELK345
were excised from the seedlings that had been germinated on medium containing 0.5 mg/l BA followed by further growth on medium
containing 0.25 mg/l BA and 0.10 mg/l IBA. 相似文献
8.
Efficient plant regeneration was achieved from callus derived from immature-cotyledon explants of oleaster ( Elaeagnus angustifolia L.). Calli were obtained on MS media containing 3% sucrose and different concentrations of TDZ. The highest rate of green,
compact and nodular callus was formed on MS medium supplemented with 1 mg/l of TDZ. Shoot organogenesis was achieved when
the callus was transferred onto MS media containing 3% sucrose and BA alone (05–4 mg/l) or BA (0.5 and 1 mg/l) combined with
NAA or IAA (0.5 and 1 mg/l). Maximum organogenesis was obtained with 1 mg/l BA in combination with 0.5 mg/l NAA. Rooting of
the shoots was achieved on MS medium supplemented with 0.2 mg/l IBA. Regenerated plantlets were acclimatized and successfully
transplanted to soil. 相似文献
9.
Procedures for callus induction, plantlet regeneration, and Agrobacterium-mediated transformation of Brassica juncea were optimized by studying several factors, including explant types, and various plant growth regulators and adjuvants, such
as silver nitrate, sucrose and agar. The highest shoot regeneration frequency was obtained from hypocotyl and cotyledonary
petiole explants on MS medium containing 3 mg/L benzylaminopurine (BA) and 2 mg/L α-naphthaleneacetic acid (NAA). Transformation
was affected by a number of factors, including explant type, selection agents, preculture duration, pre-selection conditions,
and coculture temperature. Transformation efficiencies for hypocotyl and cotyledonary petiole explants were at 65% and 69%,
respectively. 相似文献
10.
Plant regeneration was achieved through direct and indirect somatic embryogenesis in Eucalyptus camaldulensis. Callus was induced from mature zygotic embryos and from cotyledon explants collected from 10, 15, 25, and 30-day-old seedlings
cultured on Murashige and Skoog (MS) basal medium supplemented with different concentrations of naphthaleneacetic acid (NAA).
Maximum callus induction from mature zygotic embryos was obtained on MS basal medium containing 1 mg l −1 NAA. The frequency of callus development varied based on the age of the cotyledon explants 10-day-old explants giving highest
percentage on MS basal medium supplemented with 1 mg l −1 NAA. Callus obtained from mature zygotic embryos gave highest frequency of somatic embryogenesis on MS basal medium containing
0.5 mg l −1 benzyladenine (BA) and 0.1 mg l −1 NAA. Separate age wise culture of the calli, obtained from cotyledons of different ages cultured separately, revealed high
somatic embryogenic potential on callus from 10-day-old cotyledons. Direct somatic embryogenesis too was obtained from hypocotyl
explants without an intervening callus phase on MS basal medium containing 0.5 mg l −1 BA. The effects of abscisic acid (ABA), sucrose, and different strengths of MS medium on somatic embryo maturation and germination
were also investigated. Number of mature somatic embryos increased with lower concentrations (0–1 mg l −1) of ABA while no significant differences were observed at higher concentrations (2–5 mg l −1) of ABA. Compared to basal medium containing lower concentrations of sucrose (1%), the MS medium supplemented with higher
levels of sucrose (4%) showed significantly lower frequency of mature somatic embryos. Basal medium without any dilution gave
the highest number of immature embryos. However, the number of mature embryos was high at higher medium dilutions. 相似文献
11.
Oldenlandia umbellata L., commonly known as “Indian madder”, is an ancient Indian herb valued as a source of red color dye and various medicinal
products. In this study, successful protocols have been developed for induction of somatic embryogenesis and organogenesis
in O. umbellata. Emerging young leaves, shoot apices, and stems were used as explants, grown on Murashige and Skoog (MS) media supplemented
with various auxins, including indole acetic acid, indole butyric acid, napthaleneacetic acid (NAA), and 2,4-Dichlorophenoxyacetic
acid, each at levels ranging between 0.1 and 0.5 mg/l, cytokinins, including benzyladenine (BA) and kinetin, each at concentration
ranging between 0.5 and 5 mg/l, with and without coconut milk (CM) at levels of 0.5–5%. For callus induction, NAA at 2.5 mg/l
was optimal; while, for rapid embryogenic callus induction, 0.2 mg/l NAA, 0.5 mg/l BA, and 0.1% CM induced the highest frequency
(95.86%). Shoots developed upon transfer of embryogenic calli to MS medium containing 1.5 mg/l BA, 0.3 mg/l NAA and 1% CM.
For root induction, 0.3 mg/l NAA and 1.0% CM promoted highest and earliest rooting.
C. Rajasekaran contributed equally to this work. 相似文献
12.
An Agrobacterium-mediated gene transfer protocol was developed for the diploid cotton Gossypium arboreum using meristematic cells of shoot tips, followed by direct shoot organogenesis or multiple shoot induction of putative transformants.
Seven-day- old shoot tips of in vitro-germinated seedlings of G. arboreum cv. RG8 were excised by removing cotyledonary leaves and providing “V”-shaped oblique cuts on either side of explants. Excised
explants were inoculated with an overnight-grown culture of Agrobacterium tumefaciens carrying a plant cloning vector harboring the cry1Ac gene. The explants were co-cultivated in Murashige and Skoog (MS) medium supplemented with 30 mg/L acetosyringone, 100 mg/L
myoinositol, 10 mg/L thiamine, and 30 g/L glucose for three days in the dark. Following co-cultivation, explants were incubated
on the same medium supplemented with 20 mg/L kanamycin, for first three passages of 10–12 days each and subsequently on 50 mg/L
kanamycin to facilitate stable expression of transgene. Explants were then transferred to a fresh MS medium supplemented with
either kinetin (0.1 mg/L), myoinositol (100 mg/L), thiamine (10 mg/L) and glucose (30 g/L) or benzyl adenine, BA (2 mg/L),
kinetin (1 mg/L), myoinositol (100 mg/L), thiamine (10 mg/L), and glucose (30 g/L) to induce either single or multiple putative
transformant shoots, respectively. Following 6 weeks, shoots were transferred to a rooting medium consisting of liquid MS
supplemented with 0.05–0.1 mg/L NAA and glucose (15 g/L). Rooted plantlets were first acclimatized in liquid MS with 0.05 mg/L
NAA and 15 g/L glucose, transferred to plastic pots containing soilrite Mix-TC (a mixture of Irish peat moss and horticultural
grade expanded perlite, 75:25), and grown under controlled temperature and humidity conditions in a growth chamber. Acclimatized
plants were then transferred to clay pots and grown in the greenhouse. These plants were confirmed as transgenic for cry1Ac gene using polymerase chain reaction, enzyme linked imunosorbent assay, and Southern blot analyses. 相似文献
13.
The alkaloid compounds found in Pinellia ternata tubers have major bioactive components, and thus, these plant products are one of the most widely used ingredients in traditional Chinese medicines (TCMs). Under field agricultural growth conditions, however, it usually takes 2 years for tuber formation and growth. In vitro induced microtubers provide an alternative approach for the commercial production of P. ternata tubers for use in the TCM industry. The elicitation effect of supplementation with salicylic acid (SA) on the accumulation of alkaloid compounds in tubers and the related molecular regulation mechanism for biosynthesis are not well understood. In this study, we address this knowledge-gap through the development of an efficient induction system of in vitro cultured microtubers subsequently used to study the mechanism for elicitation of alkaloid compound accumulation by SA. Efficient microtuber induction was achieved by inserting petioles inversely into solid Murashige & Skoog medium (MS) followed by subculturing the morphologically expanded lower portion of the culture petioles in suspension culture, without the additional application of plant growth regulators. The in vitro microtuber induction rate achieved was 100% within 25 days of culture. When treated with 50–150 μM of SA, in vitro cultured microtubers showed higher accumulation of alkaloid compounds over the negative control. The highest accumulation detected showed an increase of 2.5-, 2.1-, 2.8-, and 3.1-fold in the concentration of total alkaloid compounds, guanosine, inosine and ephedrine, respectively, in the presence of 100 μM SA, 15 days after induction. qRT-PCR analysis of candidate genes for key enzymes in alkaloid biosynthesis indicated that CNL, CHY and BALDH are most probably responsible for the accumulation of benzoic acid and other alkaloid derivatives in the in vitro cultured microtubers following SA elicitation. This study developed an efficient in vitro microtuber induction system, and used this to determine that SA-promoted accumulation of alkaloids is associated with genes in the benzoic acid and alkaloid derivative biosynthesis pathway in P. ternata. 相似文献
14.
Summary Young leaf segments from plants growing both in vivo and in vitro were cultured on Murashige and Skoog (MS) medium supplemented with auxins [naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic
acid (2,4-D)], cytokinins [kinetin (KN) and N 6-benzyladenine (BA)] and coconut liquid endosperm (CW). The explants from mature leaves did not show any growth and turned
necrotic, while those obtained from juvenile leaves growing in vitro developed protocorm-like bodies (PLBs) at their cut surfaces within 4–8 wk depending on the growth medium. An optimum of
18 PLBs developed from leaf explants on medium supplemented with 2.0 mg l −1 (8.87 μ M) BA. Upon subculture in basal MS medium, the PLBs differentiated into plantlets within 6–8 wk. The resulting plantlets were
successfully transferred to vermiculite initially and subsequently to potting mixture; 84% of the plantlets survived after
3 mo. of transplantation. 相似文献
15.
The present study describes the direct regeneration of protocorm-like bodies (PLBs) in leaf explants of the tropical species
Oncidium flexuosum. The explants were inoculated in a solid, modified Murashige and Skoog (MS) medium with different concentrations of the growth
regulator thidiazuron (TDZ) and with or without 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA),
and kept away from light or in a 16-h photoperiod. The presence of auxins, 2,4-D, and NAA inhibited the formation of PLBs.
The highest frequency of explants that regenerated PLBs (80%) was obtained when they were maintained in a culture medium containing
1.5 μM TDZ under dark conditions. In the same culture medium but under a 16-h photoperiod, 95% of the leaf explants presented
necrosis. Therefore, darkness was crucial for the regeneration of PLBs in O. flexuosum leaf explants, which is in disagreement with the literature. PLBs developed from the division of epidermal and subepidermal
cells mainly on the adaxial side of the apex region of the explant. Plants with well-developed leaves and roots grew after
the PLBs were transferred to growth regulator-free medium under a 16-h photoperiod. 相似文献
16.
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
17.
Dormant buds from a mature tree of Populus tremula ‘Erecta’ were incubated on a Murashige and Skoog (MS) medium supplemented with 1.0 μM thidiazuron (TDZ). Induced shoots were
then proliferated on medium of MS or Woody Plant Medium (WPM), or Driver and Kuniyuki Walnut (DKW) supplemented with varying
levels of benzyladenine (BA). Overall, shoots grown on MS medium supplemented with 1.25–2.5 μM BA exhibited the highest frequency
of shoot proliferation (>95%) and more than 60% of responding explants produced more than five shoots per explant. Shoot organogenesis
was induced from both leaf and petiole explants incubated on WPM medium containing BA, or TDZ, or zeatin. Among the different
cytokinins tested, zeatin induced the highest frequency (average 72.1%) of shoot organogenesis. None of explants survived
on media containing no cytokinins within 6–8 weeks following culture. Overall, a higher frequency of shoot regeneration was
obtained from petioles than from leaf explants. The highest frequency of regeneration was achieved when petioles were incubated
on WPM containing 10–20 μM zeatin. Addition of naphthaleneacetic acid (NAA) did not have a significant effect on shoot regeneration
in all treatments. Shoot organogenesis was directly induced from petiole explants without intervening callus. Regenerated
shoots were easily rooted on all tested media supplemented with 0.5 μM NAA. Rooted plants were transferred to potting mix
and grown in the greenhouse. 相似文献
18.
The objective of this study was to determine the effect of two endophytic bacterial elicitors ( Pseudomonas sp. and Enterobacter sp.) on the production of alkaloids in protocorm-like bodies (PLBs) of Pinellia ternata Breit. Both bacterial strains increased the growth rate of P. ternata PLBs. Pseudomonas sp. promoted the differentiation of the PLBs, whereas Enterobacter sp. inhibited PLB differentiation. The bacterial strains increased guanosine production in PLBs by 9–166%, inosine production by 2–33%, and trigonelline production by 114–1140% compared to the control. For Pseudomonas sp., guanosine and trigonelline production was greater when bacterial extracts were added to the PLB suspension cultures rather than living cells (co-culture treatment). Inosine production was similar in both the bacterial extract and co-culture treatments. For the Enterobacter sp., guanosine, inosine, and trigonelline production tended to be greatest when living cells were added to the PLB suspension cultures rather than bacterial extracts. These results suggest that Pseudomonas sp. and Enterobacter sp. could increase alkaloid yield from P. ternata under field or tissue culture conditions. We also observed that Pseudomonas sp. and Enterobacter sp. produced some of the same alkaloids as their host plants. Additional study needs to be done to determine if these endophytic bacteria could be used to produce alkaloids in the fermentation industry. 相似文献
19.
A simple and effective method of regenerating Syngonium podophyllum ‘Variegatum’ via direct somatic embryogenesis has been established. Leaf and petiole explants were cultured on Murashige
and Skoog (MS) medium supplemented with N-(2-chloro-4-pyridyl)- N′-phenylurea (CPPU) or N-phenyl- N′-1,2,3-thiadiazol-5-ylurea (TDZ) with either α-naphthalene acetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4- D). Somatic embryos directly formed at one or two sides of petiole explants on MS medium supplemented 2.5 mg l −1 TDZ with 0.5 mg l −1 NAA or 2.0 mg l −1 TDZ with 0.2 mg l −1 NAA or with 0.2 and 0.5 mg l −1 2,4- D, respectively. The frequency of petiole explants with somatic embryos produced was as high as 86% when cultured on medium
containing 2.5 mg l −1 TDZ with 0.5 mg l −1 NAA. Up to 85% of somatic embryos were able to germinate after transferring onto medium containing 2.0 mg l −1 6-benzylaminopurine (BA) and 0.2 mg l −1 NAA. Approximately 50–150 plantlets were regenerated from a single petiole explant. However, there was no somatic embryo
formation from leaf explants regardless of growth regulator combinations used. Regenerated plantlets from petiole explants
were stable and grew vigorously after transplanting to a soilless container substrate in a shaded greenhouse. 相似文献
20.
An efficient and reproducible procedure is described for direct shoot regeneration in Drymaria cordata Willd. using leaf explants cultured on Murashige and Skoog (MS) medium supplemented with α-naphthalene acetic acid (NAA) and 6-benzyladenine. The regeneration frequency varied with the
plant growth regulator concentrations, orientation of the explants, and the carbon source and basal salts present in the regeneration
medium. The highest mean number of shoots per explant (10.65 ± 1.03) was recorded on MS plates containing 3% sucrose and 0.8%
agar supplemented with 0.1 mg/l NAA and 1.0 mg/l BAP. Shoot buds were induced in the basal parts of the leaf explants. Concentrations
of NAA exceeding 1 mg/l suppressed shoot regeneration. Explants bearing the entire lamina and petiole were much more responsive
than those having only the lamina. The plantlets that regenerated from the leaf explants were rooted successively on MS medium
alone or in combination with indole butyric acid (IBA). The highest mean number of root organogenesis, with 25.67 ± 3.68 roots
per leaf segment, was obtained in the presence of 1 mg/l IBA. Histological investigations of the regenerating shoots showed
that the shoot buds had emerged from epidermal cells without callus formation. More than 90% of the in vitro-propagated plants
survived when transferred to a greenhouse for acclimatization. Thus, this optimized regeneration system may be used for rapid
shoot proliferation and genetic transformation. 相似文献
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