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1.
Callus was produced on cotyledon, shoot tip, hypocotyl and root explants of twoCorchorus species on several media. Cytokinin was necessary for callus production on cotyledon explants. BothC.olitorius genotypes produced most callus on media with zeatin and either NAA or IAA, and theC.capsularis genotype produced most callus on media with IAA and either zeatin or BA. High frequencies of regenerated shoots were obtained
from shoot tip explants of both species, from the apical meristem and from callus. Media with 2.0 mg 1−1 BA were superior for both species, and media with zeatin were equally good forC.capsularis only. More regeneration was obtained for all genotypes after subculture of callus on media with 2.0 mg 1−1 zeatin. Cotyledon callus produced less regeneration, also with differences between genotypes; explants of both genotypes
ofC.olitorius produced regeneration on a medium with NAA and zeatin, and theC.capsularis genotype produced regeneration on a medium with IAA and BA. Limited regeneration from root explant callus was obtained forC.capsularis only on medium with BA and IAA. Regeneration was not obtained from hypocotyl callus. Further regeneration of shoots of both
species was obtained from secondary callus after subculture, and from nodal segments of regenerated shoots and of seedling
shoots cultured on basic MS medium without growth hormones. Roots were produced on about 80% of all shoots after transference
to medium with 0.2 mg 1−1 IBA, and rooted plantlets survived and flowered normally after transference to compost. 相似文献
2.
Cucumber explants including at least part of the cotyledon,a short section of hypocotyl, and the apical bud, are capableof producing multiple axillary buds from the seedling apex andadventitious shoots from the hypocotyl base in a medium whichcontains 2·0 mg dm3 of kinetin. Removal of theapical bud triples the number of shoots produced from the apexof explants with two intact cotyledons but does not affect shootproduction from explants with some or all of their cotyledonsremoved. The area of intact cotyledon also influences morphogenesis,as explants with both cotyledons removed, failed to produceadventitious shoots from the hypocotyl base. Culture in continuousdarkness entirely prevents shoot development from the explantbase, but has little influence on shoot production from theapex. The influence of endogenous growth regulators and apicaldominance on the morphogenesis of shoots in cucumber seedlingsare discussed. Key words: Cucumber, cotyledons, apical dominance, morphogenesis, adventitious shoots, Cucumis sativus 相似文献
3.
S. Amutha M. Muruganantham A. Ganapathi 《In vitro cellular & developmental biology. Plant》2006,42(1):26-30
Summary Prolific shoot regeneration was achieved in mungbean Vigna radiata (L.) Wilczek from 3-d-old in vitro cotyledonary node and hypocotyl explants from seedlings derived from mature seeds on Murashige and Skoog (MS) medium supplemented
with thidiazuron (TDZ) (0.9 μM). An initial exposure to TDZ for 20 d and three successive transfers to fresh medium with reduced thidiazuron levels (0.09
μM) resulted in the regeneration of 104 shoots/explant from the cotyledon and 30 shoots/explant from the hypocotyl. Thidiazuron-associated
abnormalities such as short compact shoots, fasciation and leaf growth in the form of rosettes were observed in shoots regenerated
from hypocotyl explants. Both axillary and adventitious shoot formation from the explants were confirmed by histology. Through
repectitive cycles of regeneration in the presence of TDZ, the number of shoots that could be obtained from the two explant
classes within 80 d was significantly higher than with previous reports in mungbean 相似文献
4.
Summary Factors affecting in vitro shoot production and regeneration of Cercis yunnanensis Hu et Cheng were investigated by comparing various growth regulators and explant types. For optimum shoot production from
axillary buds, Murashige and Skoog (MS) media containing 6-benzyladenine, either alone or in combination with a low concentration
of thidiazuron, resulted in the greatest number of shoots formed per explant (>3). Explants (2 mm long) containing one axillary
bud placed in directcontact with the medium yielded the most shoots per bud (1.6) when grown on growth regulator-free medium.
Root formation on 70–80% of shoot explants was accomplished using either indole-3-butyric acid or α-naphthaleneacetic acid
in the medium, with significantly more roots formed on explants possessing and apical bud than those without the bud. Direct
shoot organogenesis from leaf explants occurred on MS medium containing 10–30 μM thidiazuron, with up to 42% of leaf explants producing shoots. 相似文献
5.
Charlene Chang Ben A. Moll Kathleen B. Evenson Mark J. Guiltinan 《Plant Cell, Tissue and Organ Culture》1996,45(1):61-66
In vitro plantlet regeneration systems for the seed geranium (Pelargonium x hortorum Bailey) using cotyledon, hypocotyl and root explants were optimized by studying the influence of seedling age, growth regulators and excision orientation on organogenesis. Indole-3-acetic acid combined with zeatin yielded the highest rate of shoot production on cotyledon explants (0.2–2 shoots per explant). More shoots were produced on explants cut from the most basal region of cotyledons from 2 to 4-day-old seedlings than from older seedlings or more distal cut sites. Hypocotyl explants produced the highest number of shoots, up to 40 shoots per explant, on indole-3-acetic acid (2.8–5.6 mM) + zeatin (4.6 mM) or thidiazuron (4.5 mM). Maximum shoot formation (0.3–1.4 shoots per explant) on root explants occurred when they were cultured on medium containing zeatin. Regenerated shoots rooted best on a basal medium containing no growth regulators. There were substantial differences among cultivars in shoot formation from each of the explant systems.Abbreviations BA
6-benzylaminopurine
- 2,4-d
2,4-dichlorophenoxyacetic acid
- IAA
indole-3-acetic acid
- NAA
naphthaleneacetic acid
- TDZ
thidiazuron 相似文献
6.
S. ürük S. etiner C. Elman X. Xia Y. Wang A. Yeheskel L. Zilberstein R. Perl‐Treves A. A. Watad V. Gaba 《Engineering in Life Science》2005,5(2):169-177
Transformation of the recalcitrant melon (Cucumis melo L.) cultivars Kιrka?aç 637 and Noi Yarok was accomplished by wounding cotyledon explants by vortexing with carborundum prior to inoculation with Agrobacterium tumefaciens. The addition of silver nitrate to the regeneration‐selection medium reduced the transformation efficiency, as the percentage of the explants forming putative transgenic calli and bud‐like protuberances was decreased and no transgenic shoots were produced. Chimeric transgenic plants were obtained after the regeneration of putatively transformed callus, bud‐like protuberances, buds and shoots on selective medium with kanamycin. The treatments producing the most buds or shoots from explants after 30–40 days of cultivation were the most successful for the production of transgenic plants. Only treatments where explants were vortexed with carborundum produced transgenic melon shoots of either cultivar. Subculture every 18–20 days on fresh regeneration‐selection medium containing 50 mg/L kanamycin after either a relatively high (100 mg/L) or low level (50 mg/L) of kanamycin in the first regeneration‐selection medium was necessary for the successful transformation of cultivar Kιrka?aç 637. These techniques are now being used in breeding programs for the production of melon lines bearing resistances to zucchini yellow mosaic virus and cucumber mosaic virus, important viruses limiting agricultural production. 相似文献
7.
A high frequency shoot regeneration system for ornamental kale [Brassica oleracea L. var. acephala (D.C.) Alef.] was firstly established from seedling cotyledon and hypocotyl explants. The ability of cotyledon and hypocotyl
to produce adventitious shoots varied depending upon genotype, seedling age and culture medium. The maximum shoot regeneration
frequency was obtained when the explants from cv. Nagoya 4-d-old seedlings were cultured on Murashige and Skoog (MS) medium
supplemented with 3 mg dm−3 6-benzylaminopurine (BA) and 0.1 mg dm−3 naphthaleneacetic acid (NAA). The frequency of shoot regeneration was 65.0 % for cotyledons, 76.1 % for hypocotyls; and the
number of shoots per explant was 4.3 for cotyledons, 8.2 for hypocotyls. Hypocotyl explants were found to be more responsive
for regeneration when compared with cotyledons. Among the 4 cultivars tested, Nagoya showed the best shoot regeneration response.
The addition of 3.0 mg dm−3 AgNO3 was beneficial to shoot regeneration. Roots were formed on the base of the shoots when cultured on half-strength MS medium. 相似文献
8.
Influence of silver nitrate (ethylene inhibitor) on cucumber in vitro shoot regeneration 总被引:6,自引:0,他引:6
Mohiuddin A.K.M. Chowdhury M.K.U. Abdullah Zaliha C. Napis Suhaimi 《Plant Cell, Tissue and Organ Culture》1997,51(1):75-78
The effect of addition of silver nitrate (AgNO3) on organogenesis of proximal and distal cotyledon and hypocotyl explants of five cucumber (Cucumis sativus L.) cultivars
was investigated. Distal cotyledon and hypocotyl were unresponsive while only poor shoot regeneration was observed in proximal
cotyledon and hypocotyl explants of all cucumber cultivars. The addition of different concentrations of AgNO3 (10, 30 and 50 μM) to the medium, however, induced shoot regeneration in distal cotyledon except Suyo Long cultivar and effectively
increased shoot regeneration response as well as the number of shoots per explant in proximal cotyledon and hypocotyl of all
cucumber cultivars.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
In vitro regeneration from leaf, cotyledon and hypocotyl explants of six cultivars belonging to three species of Capsicum was achieved by direct organogenesis. The cultivar Umorok showed the best response while Meiteimorok, Haomorok, Mashingkha
and Uchithi showed intermediate response and the cultivar Chiengpi was the least responsive. Leaf and cotyledon explants regenerated
more shoots than hypocotyl explants and the maximum number of shoots were produced on Murashige and Skoog (1962) medium containing
8.8 μM 6-benzylaminopurine (BAP) with 11.4 μM indole-3-acetic acid (IAA). Elongation of shoot buds derived from different
explants was achieved on medium containing 2.8 μM IAA and the elongated shoots were rooted on medium containing 2.8 or 5.7
μM IAA and 2.4 or 4.9 μM indole-3-butyric acid (IBA). Four-week old rooted plantlets were hardened and transplanted to the
soil. The plantlets showed 90 % survival during transplantation. 相似文献
10.
Sampath Amutha Krishnan Kathiravan Sima Singer Liana Jashi Ilan Shomer Benjamin Steinitz Victor Gaba 《In vitro cellular & developmental biology. Plant》2009,45(6):758-768
Regeneration of new shoots in plant tissue culture is often associated with appearance of abnormally shaped leaves. We used
the adventitious shoot regeneration response induced by decapitation (removal of all preformed shoot apical meristems, leaving
a single cotyledon) of greenhouse-grown cotyledon-stage seedlings to test the hypothesis that such abnormal leaf formation
is a normal regeneration progression following wounding and is not conditioned by tissue culture. To understand why shoot
regeneration starts with defective organogenesis, the regeneration response was characterized by morphology and scanning electron
and light microscopy in decapitated cotyledon-stage Cucurbita pepo seedlings. Several leaf primordia were observed to regenerate prior to differentiation of a de novo shoot apical meristem from dividing cells on the wound surface. Early regenerating primordia have a greatly distorted structure
with dramatically altered dorsoventrality. Aberrant leaf morphogenesis in C. pepo gradually disappears as leaves eventually originate from a de novo adventitious shoot apical meristem, recovering normal phyllotaxis. Similarly, following comparable decapitation of seedlings
from a number of families (Chenopodiaceae, Compositae, Convolvulaceae, Cucurbitaceae, Cruciferae, Fabaceae, Malvaceae, Papaveraceae,
and Solanaceae) of several dicotyledonous clades (Ranunculales, Caryophyllales, Asterids, and Rosids), stems are regenerated
bearing abnormal leaves; the normal leaf shape is gradually recovered. Some of the transient leaf developmental defects observed
are similar to responses to mutations in leaf shape or shoot apical meristem function. Many species temporarily express this
leaf development pathway, which is manifest in exceptional circumstances such as during recovery from excision of all preformed
shoot meristems of a seedling. 相似文献
11.
K. Balaraju P. Agastian J. P. Preetamraj S. Arokiyaraj S. Ignacimuthu 《In vitro cellular & developmental biology. Plant》2008,44(5):436-441
This study describes in vitro shoot induction and plant regeneration from a mature apical meristem and nodal explants of the endangered medicinal shrub
Vitex agnus-castus. Multiple shoots were induced directly from the axis of nodal and apical meristem explants on Murashige and Skoog (MS) medium
containing 3% sucrose and different concentrations (1.0, 1.5, 2.0, and 2.5 mg/l) of 6-benzyl aminopurine (BAP) in combination
with Kinetin (Kin) and α-naphthalene acetic acid (NAA), both at 0.1 mg/l. BAP and Kinetin were used as supplements to MS basal
medium, either individually or in combination with auxins. The optimal concentration of BAP for inducing bud break was found
to be 2.0 mg/l when Kinetin was at 0.1 mg/l. Regeneration frequency was highest for both apical meristem and nodal explants
(94.5% and 90.3%, respectively) when explants were cultured on MS medium supplemented with BAP (2.0 mg/l) and Kin (0.1 mg/l).
A maximum of 7.7 ± 0.4 and 6.7 ± 0.2 shoots were obtained per explant for apical meristem and nodal explants, respectively.
Regenerated shoots, transferred to MS medium supplemented with either 1.0 or 1.5 mg/l BAP combined with 0.1 mg/l GA3, showed maximum elongation of 6.7 ± 0.4 and 6.0 ± 1.3 cm in apical meristem and nodal explants, respectively. In vitro regenerated shoots transferred to half-strength MS medium supplemented with 0.1 mg/l IBA induced 90.4% of the shoots to form
roots after 30–35 d of culture. Up to 80% of the regenerated shoots were successfully established in soil in the greenhouse. 相似文献
12.
We have investigated the usefulness of hypocotyl (cultured on N1B2 medium) and cotyledon explants (on CR medium: Murashige
and Skoog (MS) medium, 3% sucrose, 20 μm benzylaminopurine, pH 5.8) for the regeneration of shoots of the Korean radish ‘Jin
Ju Dae Pyong’. The importance of ethylene (indirectly), polyamines and gelling agent were studied in both media. Although
the addition of ethylene-inhibitors and silver nitrate to the culture media were beneficial towards shoot regeneration and
agar-based treatments (0.8% w/v) being superior in shoot production compared to agarose treatments (0.4% w/v), both explants
responded differently in culture. Hypocotyls cultured in the presence of silver nitrate or aminoethoxyvinylglycine (AVG) regenerated
significantly (p < 0.05) more shoots compared to N1B2 medium alone; supplementation of 20 μM AVG to N1B2 medium gave optimal shoot production
(40% of explants regenerating shoots). The addition of 10 μM AVG to CR medium produced maximum shoot regeneration from cotyledon
explants (60% producing shoots). Plants derived from 3-month-old cultures produced greater seed weights, larger leaves and
greater genetic variability (50–80% of cells having 20–40 chromosomes) compared to seed-derived (85–90% diploid) and plants
from 1-month-old cultures (78–88% diploid). Our results show, that if prolonged culture of explants is avoided, a large number
of phenotypically-normal plants can be produced, which in turn, could be utilized in the genetic improvement of radish. 相似文献
13.
Anne -Claire van Altvorst Svetla Yancheva Hans Dons 《Plant Cell, Tissue and Organ Culture》1995,40(2):151-157
Adventitious shoot formation was studied with leaf, stem and axillary bud explants of carnation (Dianthus caryophyllus L.). The shoot regeneration procedures were applicable for a wide range of cultivars and shoot regeneration percentages were high for all explant types. Using axillary bud explants, shoot regeneration efficiency was independent of the size of the bud and of its original position in the plant. In contrast, shoot regeneration from stem and leaf explants was strongly dependent on their original position on the plant. The most distal explants (just below the apex) showed the highest level of shoot regeneration. The adventitious shoot primordia developed at the periphery of the stem segment and at the base of leaf explants. In axillary bud, stem and leaf explants, shoot regeneration originated from node cells, located at the transition area between leaf and stem tissue. Moreover, a gradient in shoot regeneration response was observed, increasing towards the apical meristem.Abbreviations BA
benzyladenine
- NAA
naphthaleneacetic acid 相似文献
14.
Tatiana A. Vega Graciela M. Nestares Roxana Zorzoli Liliana Picardi 《Acta Physiologiae Plantarum》2006,28(5):427-431
Regeneration efficiency from three different regions of cotyledonary explants was examined in six sunflower inbred lines.
Proximal, middle and distal regions from seedling cotyledons were cultured on regeneration medium supplemented with growth
regulators. Plant regeneration by direct organogenesis was observed after four weeks. Significant differences among inbred
lines were found for regeneration percentage and average number of shoots per total explants. Also a decreasing regeneration
capacity was observed from proximal to distal sections for all inbred lines. Regeneration ability from cotyledonary explants
in this species is strongly influenced by the genotype and by the region from which the explant was obtained. The distance
to the cotyledonary node plays a preponderant role in the expression of shoot forming capacity. Shoot differentiation via seedling cotyledons depends upon the presence of the proximal region of cotyledon regardless of the genotype. 相似文献
15.
Two plant regeneration methods applicable to Leucaenaleucocephala were developed. In the first method, involvingorganogenesis via callus formation, cotyledon, hypocotyl and root segments wereinitiated on MS medium containing different concentrations ofN6-benzyladenine (BA), 2,4-dichlorophenoxyacetic acid (2,4-D), andnaphthaleneacetic acid (NAA). Both compact (type I) and friable (type II) calliwere obtained from the cotyledon and hypocotyl explants treated with differentconcentrations of the growth regulators. Shoots were generated only from thefriable calli formed from the cotyledon explants. The calli formed from thehypocotyl explants did not generate shoots and the root explants died withoutforming callus. Cotyledon explants from 3–4 day old seedlings showedmaximum callus induction compared to those from older seedlings. In a secondmethod involving direct organogenesis, excised cotyledons were cultured on 1/2MS medium containing 10–35 mg l–1N6-benzyladenine (BA) for 7–14 days. Transfer of thecotyledonsto regeneration medium containing low BA resulted in callus formation andsubsequent shoot regeneration from the base of the excised cotyledon explants,with up to 100% frequency. Regenerated shoots rooted best on a basal mediumcontaining no growth regulators. 相似文献
16.
A protocol is presented for direct adventitous shoot organogenesis and complete plant regeneration from seedling-derived explants of pomegranate (Punica granatum L.), a tropical fruit tree. Murashige and Skoog (1962) (MS) medium enriched with 8.9 mumol/L benzyladenine (BA), 5.4 mumol/L naphthaleneacetic acid (NAA) and 10% coconut water (CW) induced adventitious shoot bud differentiation in axenic seedling-derived cotyledons as well as hypocotyl segments. The cotyledons were more responsive than the hypocotyls. Addition of ethylene inhibitors such as AgNO3 (10-40 mumol/L) and aminoethoxyvinylglycine (AVG) (5-15 mumol/L) to the medium markedly enhanced regeneration frequency as well as number of shoots obtained per explant. The promotive effect of AVG and AgNO3 on shoot organogenesis was observed only in cotyledon explants. The regeneration medium containing AgNO3 (20 mumol/L) or AVG (10 mumol/L) induced adventitious shoot buds from 57% or 53% of the cotyledon explants respectively. These shoot buds developed into shoots upon transfer to a regeneration medium without AgNO3 and AVG. The promotive effect of AVG on shoot regeneration was reversed by exogenous application of 20 mumol/L 2-chloroethylphosphonic acid (CEPA), an ethylene releasing compound. On the other hand, shoot regeneration stimulated by AgNO3 was relatively less affected by CEPA. Regenerated shoots were rooted in half-strength MS medium (1/2 MS) containing 0.54 mumol/L NAA. The well rooted plantlets were acclimatized and eventually established in soil. 相似文献
17.
Summary Adventious root and shoot formation was obtained from cotyledon fragments of chestnut (Castanea sativa Mill.) and these processes followed two phases. In a first stage after detachment of the embryonic axis, the cotyledon fragments
in culture formed a cotyledon petiole, which elongated for about 6d. Thereafter, root primordia arose at the tip of the cotyledon
petioles, followed by normal root development. In some cases, the cotyledon, petioles showed adventitious shoot regeneration
from a nodular structure previously formed at the end of the petioles. The presence or absence of growth regulators did not
significantly influence root regeneration, whereas cytokinins stimulated shoot formtion. The processes of root and shoot differentiation
were studied also at the histological level. Observation with a light microscope showed that the developing root apical meristems
were connected with a vascular bundle of the cotyledon petiole. Similarly, shoot bud meristem connections were observed with
vascular tissue inside the nodular structure. 相似文献
18.
A. Mukhopadhyay N. Arumugam P. B. A. Nandakumar A. K. Pradhan V. Gupta D. Pental 《Plant cell reports》1992,11(10):506-513
Summary Protocols were developed for efficient shoot regeneration from hypocotyl and cotyledon explants of oilseed Brassica campestris (brown sarson) cv. Pusa Kalyani. These were used for genetic transformation by an Agrobacterium based binary vector carrying neomycin phosphotransferase (npt) gene and -glucuronidase (gus)-intron gene for plant cell specific expression. Transformed plants were recovered from hypocotyl explants at a frequency of 7–13%. Addition of silver nitrate markedly enhanced shoot regeneration in hypocotyl explants under non-selection conditions and was found to be an absolute requirement under selection conditions. Cotyledon explants, inspite of being more regenerative, proved to be highly refractory to transformation. Only two chimeric transformed shoots were obtained from more than 10,000 cotyledons treated with Agrobacterium. In hypocotyl explants, shoot regeneration occurred from the vascular parenchyma both with and without the intervention of callus phase. Only the shoot buds differentiating from callus tissue were positive for GUS activity. In cotyledons, shoot buds originated only directly from the vascular parenchyma, generally at a distance of about 450–625 from the cut surface. Such shoots were negative for GUS activity. 相似文献
19.
Prolific differentiation of shoot buds of Leucaena leucocephala was induced from the different plant parts viz. cotyledon, hypocotyl and leaf. Adventitious shoot bud formation was recorded
with prudent application of N6-2- (isopentenyl) adenosine and 15% (v/v) coconut water. Coconut water alone was unable to produce any beneficial effect with
regard to the shoot bud proliferation but the response was augmented with the increase in concentration of N6-2- (isopentenyl) adenosine. However supra-optimal level of N6-2-(isopentenyl) adenosine was inhibitory. Best response was recorded from the cotyledon explant at 2 mg dm−3 N6-2-(isopentenyl) adenosine compared to the other two explants. Comparative assessment was undertaken following the same experimental
protocol in liquid shake culture. The regenerated shoot buds were subcultured in plant growth regulator-free medium where
leafy shoot emergence was recorded. Optimum regeneration of roots was observed in these shoots in presence of 1 mg dm−3 α-naphthalene acetic acid. Plantlets were finally hardened following standard procedures before transplantation to the field.
In another experimental set up, the de-embryonated cotyledons regenerated shoot buds via callus formation. The regenerated
shoots and plantlets obtained through callus mediated organogenesis could be used for rapid multiplication and also for the
genetic improvement of individual clones of Leucaena leucocephala. 相似文献
20.
Callus induction and in vitro plantlet regeneration systems for safflower (Carthamus tinctorius L.) cv. Bhima using root,
hypocotyl, cotyledon and leaf explants were optimized by studying the influence on organogenesis of seedling age, media factors,
growth regulators and excision orientation. Supplementation of the medium with an auxin: cytokinin ratio < 1 enhanced the
growth rate of callus cultures; however, for 2,4-D the ratio was > 1.34–11.41 μM concentrations of growth regulators (IAA,
NAA, BA and Kinetin) in the medium were found effective for callus induction and regeneration in all explants. The calli could
be maintained over 32 months. BA (4.43 μM) combined with casein hydrolysate (10 mg l-1) yielded the highest rate of shoot
production on hypocotyl (3–6) and cotyledon (5–7) explants and cotyledonary derived callus (4–8). More shoots were produced
on explants cut from the most basal region of cotyledons from 5 to 7-day-old seedlings than from older seedlings or more distal
cut sites. Apolar placement of explants, inhibited shoot regeneration. The shoot regeneration potential remained upto 7 months
in calli developed on NAA + BA. Of three media tested, MS was superior to SH-M and B5. Rooting of shoots was not efficient;
42% of the shoots were rooted on MS medium containing sucrose (7–8%) + IAA (2.8–5.7 μM). Capitula induction was observed in
both callus mediated shoots on cotyledons and shoots on rooting medium with sucrose, IAA, NAA and IBA. Well developed plantlets
were transferred to the field with a 34% success rate.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献