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1.
A simple, high-frequency and reproducible protocol for induction of adventitious shoot buds and plant regeneration from leaf-disc
cultures of Jatropha curcas L. has been developed. Adventitious shoot buds were induced from very young leaf explants of in vitro germinated seedlings
as well as mature field-grown plants cultured on Murashige and Skoog’s (MS) medium supplemented with thidiazuron (TDZ) (2.27 μM),
6-benzylaminopurine (BA) (2.22 μM) and indole-3-butyric acid (IBA) (0.49 μM). The presence of TDZ in the induction medium
has greater influence on the induction of adventitious shoot buds, whereas BA in the absence of TDZ promoted callus induction
rather than shoot buds. Induced shoot buds were multiplied and elongated into shoots following transfer to the MS medium supplemented
with BA (4.44 μM), kinetin (Kn) (2.33 μM), indole-3-acetic acid (IAA) (1.43 μM), and gibberellic acid (GA3) (0.72 μM). Well-developed shoots were rooted on MS medium supplemented with IBA (0.5 μM) after 30 days. Regenerated plants
after 2 months of acclimatization were successfully transferred to the field without visible morphological variation. This
protocol might find use in mass production of true-to-type plants and in production of transgenic plants through Agrobacterium/biolistic-mediated transformation. 相似文献
2.
An efficient regeneration system for large-scale propagation of statice (Limonium altaica cv. Emille) was developed using leaves from mature plants. Leaf segments (5×5 mm sections) were cultured on Murashige and
Skoog's medium supplemented with N6-benzyladenine (BA) and thidiazuron (TDZ) individually and in combination with indole-3-acetic acid (IAA) and α-naphthaleneacetic
acid (NAA). Prolific direct adventitious shoot regeneration occurred on most of the media. The best response in terms of frequency
of shoot regeneration (99.5%) and number of shoots per explant (112 shoots per explant) was observed on medium supplemented
with 2.85 μM IAA and 1.14 μM TDZ. The shoots rooted easily on half strength MS medium and MS medium with indole-3-butyric
acid. In vitro propagated plants could be transferred to soil with survival rates of more than 95%.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
Pretreatment in thidiazuron improves the in vitro shoot induction from leaves in Curculigo orchioides Gaertn., an endangered medicinal plant 总被引:1,自引:0,他引:1
T. Dennis Thomas 《Acta Physiologiae Plantarum》2007,29(5):455-461
Leaf regeneration via direct induction of adventitious shoots obtained from an endangered medicinal plant, Curculigo orchioides Gaertn. by pretreating with thidiazuron. C. orchioides is an endangered medicinal herb belonging to the family Hypoxidaceae. Direct inoculation of leaf pieces on MS medium supplemented
with various concentrations of BAP (2–8 μM) or TDZ (2–8 μM) alone or in combination with NAA (0.5 and 1.0 μM) produced low
shoot induction both in terms of % response and number of shoots per explant. Hence, leaf explants were pretreated with 15,
25 or 50 μM thidiazuron (TDZ), for 6, 24 or 48 h with the aim of improving shoot regeneration from cultured explants. After
pretreatment, explants were transferred to an agar solidified MS medium that was supplemented with BAP (4 μM), TDZ (6 μM),
BAP (4 μM) + NAA (1.0 μM), TDZ (6 μM) + NAA (0.5 μM). Control explants were incubated directly on the medium without any pretreatment.
The pretreatment of explants with 15 μM TDZ for 24 h significantly promoted the formation of adventitious shoots and the maximum
response was observed on MS medium supplemented with 6 μM TDZ. In this medium, 96 % cultures responded with an average number
of 16.2 adventitious shoots per explant. The percentage of leaf explants producing shoots and the average number of shoots
per explant were significantly improved when TDZ pretreated leaves were cultured onto MS medium supplemented with BAP or TDZ
alone or in combination with NAA. The rooted plantlets were successfully transplanted to soil with 90% success. The present
investigation indicated the stimulatory role of TDZ pretreatment in regulating shoot regeneration from leaf explants of C. orchioides. 相似文献
4.
Filipendula ulmaria (L.) Maxim (meadowsweet) is a medicinal plant that is claimed to have several biological activities, including anti-tumor,
anti-carcinogenic, anti-oxidant, anti-coagulant, anti-ulcerogenic, anti-microbial, anti-arthritic, and immunomodulatory properties.
This report describes, for the first time, an efficient plant regeneration system for F. ulmaria via adventitious shoot development from leaf, petiole, and root explants cultured on Murashige and Skoog’s minimal organics
medium containing different concentrations of thidiazuron (TDZ), benzyladenine, and kinetin either alone or in combination
with different auxins. Relatively extensive/prolific shoot regeneration was observed in all three explant types with TDZ in
combination with indole-3-acetic acid (IAA). Gibberellic acid (GA3), TDZ, and IAA combinations were also tested. The best shoot proliferation was observed among root explants cultured on media
supplemented with 0.45 μM TDZ + 2.85 μM IAA + 1.44 μM GA3. Regenerated shoots were transferred to rooting media containing different concentrations of either IAA, indole-3-butyric
acid (IBA), naphthalene acetic acid, or 2,4-dichlorophenoxyacetic acid. Most shoots developed roots on medium with 2.46 μM
IBA. Rooted explants were transferred to vermiculite in Magenta containers for a 2-wk acclimatization period and then finally
to plastic pots containing potting soil. The plantlets in soil were kept in growth chambers for 2 wk before transferring to
greenhouse conditions. 相似文献
5.
Célia M. Miguel Philippe Druart M. Margarida Oliveira 《In vitro cellular & developmental biology. Plant》1996,32(3):148-153
Summary Adventitious shoot regeneration was achieved from almond leaves, cv. Boa Casta, excised fromin vitro cultures of juvenile and adult material. Murashige and Skoog (1962) medium (MS) was found to be more efficient for adventitious
shoot induction than a modified medium of Quoirin et al. (1977) when using identical growth regulator supplements. Thidiazuron
(TDZ) at 4.54, 5.90, 6.81, and 9.08 μM was used in all induction media, together with indole-3-butyric acid (IBA), indole-3-acetic acid (IAA), or a combination
of IAA and 2,4-dichlorophenoxyacetic acid (2,4-D). When N6-benzyladenine (BA) was used instead of TDZ, no adventitious shoots were induced. Leaf explants of juvenile origin yielded
the highest regeneration rates (40.0 and 38.2%) and required higher concentrations of TDZ for shoot induction than leaves
of adult origin. An increase from 15.0 to 35.3% in the regeneration ability of adult leaf explants, tested on one of the induction
media, modified medium of Quoirin et al. (1977) supplemented with 5.90 μM TDZ and 2.85 μM IAA], was achieved when donor shoots were subcultured twice on a medium with a low BA concentration of 1.33 μM. 相似文献
6.
An efficient, rapid and reproducible plant regeneration protocol was successfully developed for Cassia angustifolia using nodal explants excised from 14-day-old aseptic seedlings. Of the two cytokinins, 6-benzyladenine (BA) and thidiazuron
(TDZ) evaluated as supplements to Murashige and Skoog (MS) medium, TDZ at an optimal concentration of 5.0 μM was effective
in inducing multiple shoots. The highest rate of shoot multiplication was achieved on MS medium supplemented with 5.0 μM TDZ
and 1.0 μM indole-3-acetic acid (IAA) at pH 5.8. The regenerated shoots when subcultured on hormone free MS medium considerably
increased the rate of shoot multiplication and shoot length by end of fourth subculture passage. Rooting was achieved on the
isolated shoots using MS medium with 60 μM indole -3- butyric acid (IBA) and 1% activated charcoal for 1 week and subsequently
transferring the shootlets to half strength MS liquid media without IBA and activated charcoal. The in vitro raised plantlets
with well-developed shoot and roots were successfully established in earthen pots containing garden soil and grown in greenhouse. 相似文献
7.
Azza A. Tawfik Mohamed F. Mohamed 《In vitro cellular & developmental biology. Plant》2007,43(1):21-27
Nodular meristematic callus was induced on the basal cut surface of apical shoot explants of salvia cultured on Murashige
and Skoog (MS) medium supplemented with 4.5, 13.5, or 22.5 μM thidiazuron (TDZ). Cultures were incubated in the dark for 1 wk
and then transferred to light conditions for 4 wk. A higher percentage of explants developing callus was observed on medium
containing either 4.5 or 13.5 μM TDZ, although explants on 4.5 μM developed larger calluses. The callus was maintained on
medium containing 4.5 μM TDZ and 0.45 mM ascorbic acid. Shoot differentiation, after each of three successive maintenance
passages, was induced from callus grown on medium containing either 4.4 or 8.8 μM benzyladenine (BA). A greater number of
shoots were harvested from callus differentiated on BA (4.4 or 8.8 μM) medium with 0.45 mM ascorbic acid added. Shoots developed
roots on MS medium supplemented with 4.9 μM of indole-3-butyric acid. The addition of ascorbic acid to the shoot differentiation
medium enhanced rooting, number of roots per shoot, and survival rate. Approximately 75% in vitro plantlets were acclimatized to ex vitro conditions. Histological investigations confirmed both adventitious meristem initiation during the callus induction phase,
and subsequent organogenic shoot development on the differentiation medium. The novel protocol for the meristematic callus
induction and plant regeneration in this study may be useful for biotechnological applications for salvia improvement via
genetic transformation or mutagenesis and in vitro propagation approaches. 相似文献
8.
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
9.
The macadamia tree, an Australian native, is highly valued for its nuts. Macadamia improvement programs so far have relied on conventional breeding and selection. The production of improved cultivars required to meet future demands could be accelerated by the application of modern biotechnological techniques, but this requires an efficient and reproducible regeneration system that has not yet been established for macadamia. We report here shoot regeneration from immature cotyledon explants of macadamia. Adventitious buds were induced on the cotyledon explants from fruits collected at 140 and 190 days after full bloom (DAFB) on MS medium supplemented with either 10 or 15 μM TDZ. The addition of 2% coconut milk (CM) to 10 μM TDZ containing media resulted in enhanced adventitious bud induction from 190 DAFB explants. Further shoot development from the induced buds was depressed in media containing TDZ + CM; the addition of 0.001 μM IAA to this combination doubled shoot development, from 1.9–3.9 shoots per explant. The transfer of bud clumps to media supplemented with 8.8 μM BA alone or in combination with either 0.14 μM GA3 or 0.001 μM IAA significantly increased shoot production from the previously induced explants by 1.5–2 times of that observed in TDZ + CM medium. Histological examinations revealed that shoot regeneration was primarily by organogenesis originating from cells on or just below the cut surfaces of explants. 相似文献
10.
Guohua Ma Jinfeng Lü Jaime A. Teixeira da Silva Xinhua Zhang Jietang Zhao 《Plant Cell, Tissue and Organ Culture》2011,104(2):157-162
Ochna integerrima is a medicinal and ornamental plant in Southeastern Asia. It has been listed as a rare and endangered species in China. Here
we studied the effects of plant growth regulators and their concentrations on the induction of somatic embryogenesis and shoot
organogenesis from leaf and shoot explants of O. integerrima for the first time. Cytokinins played a crucial role in somatic embryogenesis and shoot organogenesis. Among them, a higher
concentration of thidiazuron (10.0–15.0 μM TDZ) could induce both somatic embryogenesis and adventitious shoot formation whereas
low concentrations of TDZ (5.0 μM) could only induce adventitious shoots. However, 6-benzyladenine (BA at 5–15 μM) could only
induce adventitious shoots. Shoot explants induced more adventitious shoots and somatic embryos than leaf explants when cultured
on medium with the same concentration (5–15 μM) of TDZ or 15 μM BA. Medium containing 0.5 μM α-naphthaleneacetic acid and
8 μM indole-3-butyric acid and 0.1% activated charcoal could induce adventitious roots within 1 month. An efficient mass propagation
and regeneration system has been established. 相似文献
11.
Murugesan Dhandapani Doo Hwan Kim Seung-Beom Hong 《In vitro cellular & developmental biology. Plant》2008,44(1):18-25
High-frequency plant regeneration of C. roseus cv. ‘little bright eye’ via somatic embryogenesis and organogenesis from five out of six explants was standardized. Two factors
were found to be important for regeneration: (1) the type of explants, and (2) the combination and concentrations of plant
growth regulators. The highest regeneration percentage through somatic embryogenesis was obtained from mature zygotic embryo
in MS medium supplemented with 7.5 μM of thidiazuron (TDZ). The mature embryo also regenerated efficiently via organogenesis
in MS medium supplemented with either 2.5 μM TDZ or 5.3 μM α-naphthalene acetic acid (NAA) and 2.2 μM 6-benzylaminopurine
(BA). Hypocotyl and cotyledon did not induce somatic embryogenesis and organogenesis in TDZ-containing medium but gave a maximum
percentage of shoots in MS medium supplemented with 5.3 μM NAA and 2.2 μM BA. Stem nodes and meristem tips showed better regeneration
via organogenesis in the medium supplemented with NAA and BA and in lower concentrations of TDZ. 相似文献
12.
G. G Ning S. P Bai M. Z Bao L. Liu 《In vitro cellular & developmental biology. Plant》2007,43(2):95-100
Using immature embryos and cotyledons as explants, a successful system to culture immature embryos and induce direct regeneration
from cotyledons was established for Prunus mume “Xuemei”. For immature embryo culture, a high frequency of plantlet formation (89.5%) from the embryonic axis was obtained
using half-strength Murashige and Skoog (1/2 MS) medium supplemented with 13.2 μM 6-benzyladenine (BA) and 2.7 μM 1-naphthaleneacetic
(NAA). Shoots formed directly from cotyledons with the embryo axis intact when explants were cultured on 1/2 MS medium containing
2.2 μM BA with different combinations of NAA (2.7, 5.4 μM) and indole-3-butyric acid (IBA) (0, 2.5, 5.0 μM). Better results
were achieved when the embryonic axis was removed from the cotyledons and cultured on 1/2 MS medium supplement with 13.2 μM
BA, 2.7 μM NAA or 2.2 μM BA, 2.2 μM thidiazuron (TDZ), and 2.7 μM NAA, respectively. Regenerated shoots were successfully
rooted on 1/2 MS or Woody Plant medium (WPM) supplemented with 2.5–5.0 μM IBA. The effect of the embryonic axis, BA, and TDZ
on cotyledon regeneration was investigated in detail. Rooted plantlets were transferred to soil successfully. 相似文献
13.
Tang Wei Harris Latoya C. Outhavong Vilay Newton Ronald J. 《Plant Cell, Tissue and Organ Culture》2004,78(3):237-240
The effects of different plant growth regulators on in vitro adventitious shoot formation in Virginia pine (Pinus virginiana Mill.) zygotic embryo explants were quantitatively evaluated. Using Tang and Ouyang (1999) (TE) basal medium supplemented
with 11.4 μM indole-3-acetic acid (IAA) and 2.2 μM N6-benzyladenine (BA), callus was observed after 3–6 weeks of culture. Calluses were transferred to TE basal medium supplemented
with 0.49 μM indole-3-butyric acid (IBA) and 8.8 μM BA for 6–9 weeks, where they produced numerous small shoot primordia.
They were then transferred to TE basal medium supplemented with 0.49 μM IBA and 4.4 μM BA to promote growth and elongation
of adventitious shoots. After elongated shoots were transferred to TE medium containing 0.05 μM α-naphthaleneacetic acid (NAA)
for 6 weeks, adventitious roots were formed. Regenerated plantlets were established in soil in greenhouse. 相似文献
14.
Summary A method for adventitious shoot induction from petiole explants of Heracleum candicans is reported. Shoot buds were induced on Murashige and Skoog (MS) medium with 4.4μM 6-benzylaminopurine (BA) and 1.1 μM 2,4-dichlorophen-oxyacetic acid (2,4-D). A wound response in the presence of BA and 2,4-D at the time of culture was necessary
for inducing shoot buds. The shoot bud regeneration was significantly influenced by size, type and orientation of explants
on the culture medium. These shoot buds developed into 4–5 cm shoots upon transfer to a medium containing 1.1μM BA and 0.5 μM α-naphthaleneacetic acid (NAA). The regenerated shoots formed rooted plantlets on MS medium supplemented with 4.9 μM indole-3-butyric acid (IBA). About 15 plants were established in the field for further evaluation. 相似文献
15.
H. Y. Seo Y. J. Kim T. I. Park H. S. Kim S. J. Yun K. H. Park M. K. Oh M. Y. Choi C. H. Paik Y. S. Lee Y. E. Choi 《In vitro cellular & developmental biology. Plant》2007,43(3):209-214
Sesamum indicum L. was used as an important oil crop in the world. An efficient protocol for in vitro plant regeneration via adventitious shoot formation from deembryonated cotyledon explants isolated from mature seeds of sesame
is developed. Optimal medium for direct adventitious shoot formation was Murashige and Skoog (MS) medium with 22.2 μM 6-benzylaminopurin
(BA) and 5.7 μM indole-3-acetic acid (IAA). Abscisic acid (3.8 μM ABA) and AgNO3 (29.4 μM) were effective in enhancing the frequency of adventitious shoot formation. Preculture of cotyledon explants on
high sucrose concentration (6–9%) for 2 wk and subsequent transfer to 3% sucrose enhanced the frequency of adventitious shoot
induction. Root formation from the adventitious shoots was easily achieved on MS medium containing 2.7 μM of α-naphthalene
acetic acid (NAA). Regenerated plantlets were acclimatized on sand and peat moss (1:1), showing 95% survival with subsequent
flowering and seed set. We established the high-frequency plant regeneration via adventitious shoot formation in S. indicum L. 相似文献
16.
A simple, rapid and efficient protocol for micropropagation of Cardiospermum halicacabum via axillary bud multiplication has been successfully developed. The organogenic competence of nodal segments was investigated
on Murashige and Skoog (MS) medium supplemented with different concentrations of benzyladenine (BA), kinetin (Kn), thidiazuron
(TDZ) and 2-isopentenyladenine (2-iP). Multiple shoots differentiated directly without callus mediation within 4 weeks when
explants were cultured on a medium fortified with cytokinins. The maximum number of shoots (14.83 ± 0.52) was developed on
a medium supplemented with 0.3 μM TDZ. Such proliferating shoots when subcultured onto MS media devoid of TDZ gave the highest
rate of shoot multiplication (35.66 ± 1.00) by the end of fourth subculture passage. Elongated shoots were rooted on 1/3 MS
medium augmented with 0.5 μM IAA. The plantlets thus obtained were successfully hardened and transferred to greenhouse. 相似文献
17.
Hongyan Dai Zhihong Zhang Xiuwu Guo 《In vitro cellular & developmental biology. Plant》2007,43(1):2-8
Hawthorn (Crataegus spp.) is an important plant with a long history as an ornamental and a source of medicine. A protocol is outlined for adventitious
bud regeneration from leaf and cotyledon explants of Chinese hawthorn (C. pinnatifida Bge. var. major N.E.Br.). Adventitious buds were induced on both the leaves of sprouting winter buds and the leaves of in vitro plants, but the percentage of bud regeneration from leaves of in vitro plants was very low—less than 6%. On N6 medium supplemented with 31.08 μM BA and 9.67 μM NAA, the percentages of bud regeneration
from leaves of sprouting winter buds of cultivars “Liaohong” and “Qiujinxing” were 31.4% and 17.6%, respectively. The regeneration
abilities of three kinds of cotyledon explants, immature cotyledon, mature cotyledon, and cotyledon leaf, were compared. The
percentage of bud regeneration from cotyledon leaves was higher. On MS media supplemented with 4.44 μM BA and 4.54–9.08 μM
TDZ, the percentages of bud regeneration from cotyledon leaves of cultivars “Qiujinxing” and “Xiajinxing” were 27.7 ± 7.8%
and 20.1 ± 4.7%, respectively, and the numbers of buds per explant were 5.9 ± 1.6 and 3.2 ± 0.7, respectively. On B5 medium
supplemented with 2.22 μM BA, 2.32 μM Kn, and 0.57 μM IAA, adventitious buds grew quickly and 80–100% of buds developed into
shoots. The shoots rooted successfully with the two-step rooting method. Ninety days after transplantation, more than 80%
plants were survived. This system of adventitious bud regeneration from leaf and cotyledon explants could be useful for the
genetic transformation and polyploidization of Chinese hawthorn. 相似文献
18.
Summary Protocols for both axillary bud proliferation and shoot organogenesis of Euphorbia pulchurrima Winter RoseTM were developed using terminal buds and leaf tissues. Greenhouse-grown terminal buds were placed on Murashige-Skoog (MS) basal
medium supplemented with various concentrations of either benzlyaminopurine (BA) or thidiazuron (TDZ). Explants produced the
greatest number of axillary buds on media containing between 2.2 and 8.8 μM BA. The number of explants that produced axillary buds increased with increasing BA concentration. TDZ at concentrations
between 2.3 and 23.0 μM caused hyperhydricity of shoots and were not effective in promoting shoot proliferation. The most calluses and shoots were
produced from leaf midvein sections from in vitro grown plants placed on the medium containing 8.8–13.3 μM BA and 17.1 μM indole-3-acetic acid (IAA) for 1 mo. before transferring to the medium containing only BA. Adventitious buds were produced
only from red-pigmented callus, and explants that produced callus continued to produce adventitious shoots in the presence
of IAA. Five-mo.-old shoots derived from shoot culture or organogenesis rooted readily in artificial soil with or without
treatment with indolebutyric acid, and were acclimatized in the greenhouse. 相似文献
19.
Protocols for in vitro propagation of non-toxic variety of J. curcas through axillary bud proliferation and direct adventitious shoot bud regeneration from leaf segments have been established.
Shoot bud proliferation from axillaries was assessed on an initial basal Murashige and Skoog (MS) salt medium supplemented
with different concentrations of benzyladenine (BA), kinetin and thidiazuron (TDZ) followed by subculture to medium with 4.4-8.9
μM BA. Regardless of the concentration of BA in the subculture medium, shoot multiplication rate was optimum (10–12.3) with
primary culture on medium supplemented with 2.3–4.5 μM TDZ. Efficient adventitious shoot regeneration from leaf tissues was
achieved with culture on medium with 8.9–44.4 μM BA + 4.9 μM indole-3-butyric acid (IBA) followed by transfer to medium supplemented
with 8.9 μM BA + 2.5 μM IBA. Similarity index between toxic Indian variety and the non-toxic variety based on 435 RAPD markers
was 96.3%. Crossing studies followed by phorbol ester quantitation revealed that outcrosses with toxic J. curcas do not affect the phorbol ester content of seeds borne on the non-toxic variety. 相似文献
20.
Attempts were made to study the effect of thidiazuron (TDZ) on adventitious shoot induction and plant development in Paulownia tomentosa explants derived from mature trees. Media with different concentrations of TDZ in combination with an auxin were used to
induce adventitious shoot-buds in two explant types: basal leaf halves with the petiole attached (leaf explant) and intact
petioles. Optimal shoot regeneration was obtained in leaf explants cultured on induction medium containing TDZ (22.7 or 27.3 μM)
in combination with 2.9 μM indole-3-acetic acid (IAA) for 2 weeks, and subsequent culture in TDZ-free shoot development medium
including 0.44 μM BA for a further 4-week period. The addition of IAA to the TDZ induction medium enhanced the shoot-forming
capacity of explants. The caulogenic response varied significantly with the position of the explant along the shoot axis.
The highest regeneration potential (85–87%) and shoot number (up to 17.6 shoots/explant) were obtained in leaf explants harvested
from the most apical node exhibiting unfolded leaves (node 1). An analogous trend was also observed in intact petiole explants,
although shoot regeneration ability was considerably lower, with values ranging from 15% for petioles isolated from node 1
to 5% for those of nodes 2 and 3. Shoot formation capacity was influenced by the genotype, with regeneration frequencies ranging
from 50% to 70%. It was possible to root elongated shoots (20 mm) in basal medium without growth regulators; however, rooting
frequency was significantly increased up to 90% by a 7-day treatment with 0.5 μM indole-3-butyric acid, regardless of the
previous culture period in shoot development medium (4 or 8 weeks). Shoot quality of rooted plantlets was improved not only
by IBA treatment but also by using material derived from the 4-week culture period. Regenerated plantlets were successfully
acclimatized in the greenhouse 8 weeks after transplanting. 相似文献