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1.
Multiple shoot formation from cotyledonary node segments of Eastern redbud   总被引:4,自引:0,他引:4  
A procedure for multiple shoot formation from cotyledonary node explants of Eastern redbud (Cercis canadensis L.) cultured on DKW medium containing benzyladenine (BA) and thidiazuron (TDZ) was developed. Explants on medium with TDZ in combination with BA produced higher numbers of shoots than with either cytokinin alone. The highest number of shoots (7.8 to 9.8 shoots per explant) was obtained when explants from 4 to 10 day-old seedlings were treated with a combination of 10 or 15 μM BA and 0.5 or 1.0 μM TDZ for 20 days before being transferred to the same medium without TDZ. The number of shoots formed was increased from 5.8 to 7.2 shoots per explant by cutting through the cotyledonary node prior to culture. Histological studies indicated that the shoots were formed from actively dividing cells located at the axillary bud region. Shoots formed roots in half strength woody plant medium (WPM) supplemented with 10 to 200 μM indole-3-butyric acid (IBA) cultured for 15 days prior to transfer to greenhouse medium.  相似文献   

2.
Plant regeneration from the nodal explants of 1-month-old in vitro grown plants and cotyledonary node explants of 15-days-old seedlings of Sterculia urens is reported. Nodal explants were grown on MS medium supplemented with various growth regulators like BA, KIN and TDZ. For shoot induction 13.3 μM BA, 0.9 μM TDZ and 9.3 μM KIN were found optimum. Among the three growth regulators 0.90 μM TDZ was used for the growth of cotyledonary node explants. An average of 8.6 shoots per node and 11.2 shoots per cotyledonary node were observed in 4 to 5 weeks. These shoots were subsequently rooted in vitro on half strength MS medium containing various concentrations of auxins like IBA and NAA. The best concentrations for rooting of shoots were 19.7 μM IBA and 16.1 μM NAA. Plantlets were acclimatized to ex vitro conditions and established in the field.  相似文献   

3.
In vitro propagation of northern red oak (Quercus rubra) shoots was successful from cotyledonary node explants excised from 8-wk-old in vitro grown seedlings. Initially, four shoots per explant were obtained on Murashige and Skoog (MS) medium supplemented with 4.4 μM 6-benzylaminopurine (BA), 0.45 μM thidiazuron (TDZ), and 500 mg l−1 casein hydrolysate (CH) with a regeneration frequency of 64.7% after 3 wk. Subculturing explants (after harvesting shoots) to fresh treatment medium significantly increased shoot bud regeneration (16.6 buds per explant), but the buds failed to develop into shoots. A higher percentage (73.3%) of the explants regenerated four shoots per explant on woody plant medium (WPM) supplemented with 4.4 μM BA, 0.29 μM gibberellic acid (GA3), and 500 mg l−1 CH after 3 wk. Explants subcultured to fresh treatment medium after harvesting shoots significantly increased shoot regeneration (16 shoots per explant). Shoot elongation was achieved (4 cm) when shoots were excised and cultured on WPM supplemented with 0.44 μM BA and 0.29 μM GA3. In vitro regenerated shoots were rooted on WPM supplemented with 4.9 μM indole-3-butyric acid. A higher percentage regeneration response and shoot numbers per explant were recorded on WPM supplemented with BA and GA3, than on MS medium containing BA and TDZ. Lower concentrations of BA and GA3 were required for shoot elongation and prevention of shoot tip necrosis. Each cotyledonary node yielded approximately 20 shoots within 12 wk. Rooted plantlets were successfully acclimatized.  相似文献   

4.
An efficient protocol is described for large scale in vitro propagation of east Indian rosewood (Dalbergia latifolia Roxb.) using cotyledonary nodes derived from axenic seedlings. Of the four different cytokinins tested, BA was most effective in inducing multiple shoot buds in the explants. High frequency shoot proliferation (93%) coupled with maximum number of shoot formation (10-12 shoots/explant) was recorded on Murashige and Skoog’s medium supplemented with 2.0 mg/l BA. The frequency of shoot proliferation declined at higher levels of cytokinins. Shoot culture was multiplied by subculturing the original cotyledonary node on a fresh shoot multiplication medium each time aHer excising the newly formed shoots. Shoots obtained from each passage were multiplied further as nodal explants and each node produced 3-4 shoots. In two months from a single cotyledonary node, about 90 shoots were obtained. Rooting was induced in 72% of the regenerated shoots on half-strength MS containing IAA, IBA and IPA each at 1.0 mg/l. Rooted plantlets were hardened off and eventually established in soil.  相似文献   

5.
A procedure for multiple shoot formation from somatic embryo explants of Eastern redbud (Cercis canadensis L.) cultured on DKW medium containing benzyladenine (BA) and thidiazuron (TDZ) was developed. TDZ in combination with BA produced more shoots than either treatment alone. The highest number of shoots (3.3 to 3.4 shoots per explant) was obtained from partially desiccated and wounded explants treated with a combination of 5 or 10 M BA and 0.5 or 1.0 M TDZ for 20 days before being transferred to the same medium without TDZ. The number of shoots formed was increased from 1.5 to 3.2 shoots per explant by cutting through the cotyledonary node prior to culture. In addition, the frequency of explants forming shoots was increased by desiccation of somatic embryo explants to approximately 50% moisture and by using somatic embryos with two well formed cotyledons as explants.Abbreviations ABA abscisic acid - BA benzyladenine - CRD Completely randomized design - DKW Driver and Kuniyuki medium - LSD Least significant differences - TDZ thidiazuron  相似文献   

6.
A procedure for multiple shoot formation from cotyledonary node explants of faba bean (Vicia faba L.cv.S.Ghdar) cultured on MS medium containing benzyladenine (BA) and thidiazuron (TDZ) was developed. Explants on medium with TDZ in combination with BA produced a higher number of shoots than with either cytokinin alone. The highest number of shoots was obtained when explants from 7-day-old seedlings were cultured on MS medium supplemented with TDZ and BA (2 mgl–1 each) for 31 days before transfer to hormone-free MS medium for elongation. Shoots produced in vitro were rooted on half-strength agar-solidified MS basal medium or with 0.25 or 0.5 mgl–1 naphthalenacetic acid (NAA) prior to transfer to green house conditions. This procedure was found to be applicable to seven other cultivars of faba bean from widely diverse provenances. Thus, it can be advantageously applied to the production of transgenic faba bean plants.  相似文献   

7.
Rapid-cycling fast plants (Brassica rapa; RCBr) is also known as Wisconsin Fast Plant and is widely used in K-12 and undergraduate studies. RCBr has a short generation time (seed-to-seed in 30–60 days), which allows for the completion of experiments in a semester. Previous studies have shown that cotyledonary explants with attached petioles are capable of generating shoots. However, there is no published adventitious shoot regeneration protocol to date. Sterile cotyledonary explants were excised; all edges and petioles were removed. Five-day-old cotyledonary explants produced shoots on a Murashige and Skoog medium containing 1.5 mg/L thiadiazuron (TDZ) and 0.5 mg/L 1-naphthaleneacetic acid (NAA) (FPM I) at a mean rate of 8.8%. This rate increased to 14.8% in explants placed on FPM I medium supplemented with 5.0 mg/L silver nitrate (AgNO3) (SRM 2). The rate increased to 32.5% when 5-day-old explants, excised from the part of the cotyledon nearest to the petiole, were placed adaxial side up on SRM 2 medium. The shoot regeneration rate increased to 44.5% using 4-day-old cotyledonary explants. A shoot regeneration rate of 23% was observed among 9-day-old leaf explants. Shoots from cotyledonary explants were elongated on basal medium with 0.5 mg/L NAA, rooted on basal medium, and later acclimatized. This is the first report of shoot regeneration from cotyledonary explants of rapid-cycling Brassica rapa without pre-existing meristematic tissues.  相似文献   

8.
In vitro studies were initiated with Withania somnifera (L.) Dun. for rapid micropropagation of selected chemotypes using nodes, internodes, hypocotyls and embryo explants. Direct regeneration of shoot buds was observed in MS basal medium supplemented with various concentrations of either benzyladenine (BA) or thidiazouron (TDZ) depending on the explant. Nodal explants formed multiple shoots both from pre-existing and de novo buds on Murashige and Skoog's medium (MS) containing 0.1–5.0 mg l−1 BA and a ring of de novo shoot buds on MS medium containing 0.2 and 0.3 mg l−1 TDZ. Internodal explants formed shoot buds on MS with 1.0 and 5.0 mg l−1 BA while the hypocotyl explants gave rise to multiple shoots only on MS with 0.5 mg l−1 BA. Isolated embryos gave rise to many shoot buds on MS with 0.2 and 0.3 mg l−1 TDZ. The shoot buds elongated and rooted either on MS medium with 0.01 mg l−1 BA or on half strength MS medium lacking growth regulators, which depended upon the growth regulator used in the shoot bud induction medium. Except for the embryo-derived plantlets, all other plantlets could be acclimatized with 100% success. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

9.
A protocol is presented for micropropagation of an economically important timber-yielding forest tree, Dalbergia sissoo Roxb. (Sissoo). Multiple shoots were induced from cotyledonary nodes derived from 1-week-old axenic seedlings on Murashige and Skoog's medium containing either N 6-benzyladenine (BA), kinetin (Kn), isopentenyladenine (2iP) or thidiazuron (TDZ), with BA being the most effective growth regulator. High-frequency shoot proliferation (99%) and maximum number of shoots per explant (7.9 shoots) were recorded with BA at an optimum level of 8.9 μM. Concentrations of all cytokinins tested above the optimum level markedly reduced the frequency of shoot proliferation. A proliferating shoot culture was established by repeatedly subculturing the original cotyledonary node on shoot multiplication medium after each harvest of the newly formed shoots. Primary shoots were multiplied as nodal explants, and from each stem node 2 or 3 shoots developed. Thus, 60–70 shoots were obtained in 3 months from a single cotyledonary node. About 91% of the shoots developed roots following transfer to half-strength MS medium containing a combination of 5.7 μM indole-3-acetic acid, 4.9 μM indole-3-butyric acid and 5.3 μM indole-3-propionic acid. Eighty percent of the plantlets were successfully acclimatized and established in soil. Received: 1 October 1997 / Revision received: 31 March 1998 / Accepted: 7 April 1998  相似文献   

10.
A protocol for multiple shoot induction from cotyledonary node explants of Terminalia chebula Retz. has been developed. Germination frequency of embryos (up to 100 %) was obtained on Murashige and Skoog (MS) medium supplemented with 0.5 mg dm–3 gibberellic acid (GA3). Maximum number of shoots (6.4 shoots per cotyledonary node) was obtained on half-strength MS + 0.3 mg dm–3 GA3+ 1.0 mg dm–3 indole-3-butyric acid (IBA) + 10.0 mg dm–3 benzylaminopurine (BAP) after 4 weeks of culture. When the cotyledonary nodes along with the axillary shoot buds were allowed to grow in the same medium upto 19.2 shoots were obtained after 8 – 9 weeks. Best rooting (100 %, 5.5 roots per shoot) was observed when shoots were excised and transferred to half-strength MS medium containing 1.0 mg dm–3 IBA + 1 % mannitol and 1.5 % sucrose. Survival of rooted plants in vivo was low (35 – 40 %) when they were directly transferred to soil in glasshouse. However, transfer to soil with MS nutrients and 1.0 mg dm–3 IBA in culture room for a minimum duration of 2 weeks increased the survival percentage of plants to 100 %.  相似文献   

11.
A simple and efficient micropropagation system was developed for Cotoneaster wilsonii through node and shoot tip explants obtained from mature field-grown plants. Of the two explants, node explants were found to be the most effective for axillary shoot proliferation. The highest frequency of shoot induction was achieved when nodal explants were incubated on Murashige and Skoog (MS) medium supplemented with 0.5 mg L−1 thidiazuron (TDZ) and 0.1 mg L−1 α- naphthaleneacetic acid (NAA) with an average of 34 shoots per explant. The microshoots were separated from the multiple shoots and subcultured on MS medium supplemented with 3% (w/v) sucrose and 0.8% (w/v) agar for further shoot growth. Maximum rooting was obtained on half-strength MS medium supplemented with 0.5 mg L−1 indole-3-butyric acid (IBA). The in vitro-grown plantlets were successfully acclimatized in a glasshouse with 98% of survival. High concentrations of TDZ (1.5–2.0 mg L−1) and repeated subcultures resulted hyperhydric shoots. Supplementation of the culture medium with silicon significantly reduced the induction of hyperhydric shoots. Increasing silicon concentration significantly decreased malondialdehyde content of the regenerated shoots. Data indicate that addition of silicon to the culture medium can effectively control hyperhydricity.  相似文献   

12.
Summary An efficient and reproducible protocol for the regeneration of shoots at high frequency was developed by using explants derived from the axillary meristems from the cotyledonary nodes of in vitro-germinated seedlings of chickpea (Cicer arietinum L.). Culture conditions for various stages of adventitious shoot regeneration including the induction, elongation, and rooting of the elongated shoots were optimized. The medium for synchronous induction of multiple shoot buds consisted of Murashige and Skoog basal medium (MS) with low concentrations of thidiazuron (TDZ), 2-isopentenyladenine (2-iP), and kinetin. Exclusion of TDZ and lowering the concentration of 2-iP and kinetin in the elongation medium resulted in faster and enhanced frequency of elongated shoots. Cultivation of the stunted shoots on MS with giberellic acid (GA3) increased the number of elongated shoots from the responding explants. pH of the medium played a very crucial role in the regeneration of multiple shoot buds from the explants derived from cotyledonary nodes. A novel rooting system was developed by placing the elongated shoot on a filter paper bridge immersed in liquid rooting medium that resulted in rooting frequency of up to 90%. A comprehensive protocol for successful transplantation of the in vitro-produced plants is reported. This method will be very useful for the genetic manipulation of chickpea for its agronomic improvement.  相似文献   

13.
A comparative performance of two explants types (CN and Nodal) for their efficiency to induce multiple shoot regeneration in Clitoria ternatea has been carried out. Thidiazuron (TDZ) in different concentrations (0.05–2.5 μM) was used as a supplement to the Murashige and Skoog’s (MS) basal media. Explant type apart, two factors viz. concentration and exposure duration to TDZ played an important role in affecting multiple shoot regeneration. Cotyledonary node explants produced the best results at 0.1 μM TDZ, while in nodal explants the highest rate of shoot formation was achieved on MS medium supplemented with 1.0 μM TDZ. In both the explants, shoot multiplication increased when the regenerated shoots were subcultured on hormone free MS medium after 4 weeks of exposure to TDZ. Among the two, cotyledonary node explants produced considerably higher number of shoots at a comparatively lower concentration of TDZ than nodal explants. The regenerated shoots rooted best on MS medium containing 1.0 μM indole-3-butyric acid (IBA) and were successfully established in pots containing garden soil with 88 % survival rate. All the regenerated plants showed normal morphology and growth characteristics.  相似文献   

14.
Summary Adventitious shoot induction and elongation was compared between root and petiole explants of Kentucky coffeetree (Gymnocladus dioicus L.) explants treated with a factorial combination of benzylaminopurine (BA) and thidiazuron (TDZ). Petiole explants initiated more adventitious shoots compared to root explants. Up to 83% of petiole explants initiated shoots compared to 67% of root explants. Maximal shoot induction was approximately 12 or five shoots per responding explant for petiole and root explants, respectively. For both explant types, TDZ was more effective than BA for shoot induction. There was an interaction between BA and TDZ on shoot induction in petiole explants, with the greatest percentage of explants forming shoots and the highest number of shoots initiated on the combination of 0.5 μM TDZ plus 10μM BA and 1.0μM TDZ plus 5 or 10 μM BA. In contrast, increasing concentrations of BA inhibited shoot initiation in root explants with and without TDZ. While BA inhibited shoot initiation in root explants, it promoted shoot initiation in petiole explants. In contrast, TDZ was equally effective at inducing shoots in root and petiole explants. This suggests that root and petiole explants of Kentucky coffeetree could be a useful model system for studying the differences, in apparent mode of action between TDZ and BA on adventitious shoot initiation.  相似文献   

15.
Catharanthus roseus (L.) G. Don is an economically and medicinally important plant since its leaves and flowers contain terpenoid indole alkaloids. The present study, for the first time, encompasses the influence of silver nitrate (AgNO3), in consort with cytokinins like N 6-benzyladenine (BA) and 6-furfurylaminopurine (kinetin), to regenerate multiple shoots from nodal segments explants and to induce high-frequency precocious flowering of C. roseus under in vitro condition. Synergistic effect of equal concentrations of BA and kinetin was enhanced following the amalgamation of AgNO3. As high as 98% explants responded to multiple shoot initiation and proliferation in Murashige and Skoog medium supplemented with 3 µM BA, 3 µM kinetin and 0.1 µM AgNO3. As many as 7 shoots were developed per explant following 12 days of inoculation. Continuous culture in the same medium for 21 days induced precocious flowering from 75% shoots, wherein a maximum of ~?6 (5.67?±?0.88) flowers was observed per in vitro shoot. On the other hand, in the combinations of BA and kinetin excluding AgNO3, a maximum of 6.67% explants responded and initiated merely 3.33 shoots per explant. Nevertheless, no induction of flower was observed in the media devoid of AgNO3. Our results on the induction and proliferation of multiple shoots with simultaneous flowering would help the global pharmaceutical industry to produce in vitro shoots and flowers in bulk, as an alternative source of alkaloids.  相似文献   

16.
A successful, efficient system for multiple soybean shoot induction of soybean [Glycine max (L.) Merr.] is reported. Multiple shoots were induced from cotyledonary nodes and hypocotyl segments cultured on media supplemented with 2 mg/l thidiazuron (TDZ) or 1.15 mg/l benzyladenine (BA). It was found that TDZ induced adventitious shoots more efficiently than BA and that hypocotyl segments promoted more adventitious shoots than cotyledonary nodes. The optimal TDZ concentrations for shoot organogenesis from hypocotyl segments were between 1 and 2 mg/l. Basal media also influenced the efficiency of shoot organogenesis. The frequency of adventitious shoot formation tended to increase when the salt concentration in the basal media supplemented with 2 mg/l TDZ was reduced. Two media (1/2B5 and 1/2L2) stimulated shoot organogenesis efficiently from hypocotyl segments. This method can thus be advantageously applied in the production of transgenic soybean plants. Received: 3 July 1996 / Accepted: 9 May 1997  相似文献   

17.
Leucaena leucocephala is a fast growing multipurpose legume tree used for forage, leaf manure, paper and pulp. Lignin in Leucaena pulp adversely influences the quality of paper produced. Developing transgenic Leucaena with altered lignin by genetic engineering demands an optimized regeneration system. The present study deals with optimization of regeneration system for L. leucocephala cv. K636. Multiple shoot induction from the cotyledonary nodes of L. leucocephala was studied in response to cytokinins, thidiazuron (TDZ) and N6-benzyladenine (BA) supplemented in half strength MS (½-MS) medium and also their effect on in vitro rooting of the regenerated shoots. Multiple shoots were induced from cotyledonary nodes at varied frequencies depending on the type and concentration of cytokinin used in the medium. TDZ was found to induce more number of shoots per explant than BA, with a maximum of 7 shoots at an optimum concentration of 0.23 µM. Further increase in TDZ concentration resulted in reduced shoot length and fasciation of the shoots. Liquid pulse treatment of the explants with TDZ did not improve the shoot production further but improved the subsequent rooting of the shoots that regenerated. Regenerated shoots successfully rooted on ½-MS medium supplemented with 0.54 µM α-naphthaleneacetic acid (NAA). Rooted shoots of Leucaena were transferred to coco-peat and hardened plantlets showed ≥ 90 % establishment in the green house.Key words: Cotyledonary nodes, Multiple shoot induction, Pulse treatment, TDZ  相似文献   

18.
A simple and efficient regeneration protocol was established for soybean [Glycine max (L.) Merrill]. Cotyledonary node explants from 7-day-old in vitro seedlings were used as explants. The effect of different plant growth regulators [N 6 –benzyladenine (BA), kinetin (KT), thidiazuron (TDZ), gibberellic acid (GA3), zeatin riboside (ZTR), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA)] along with polyamines (Spermidine, spermine, and putrescine) were investigated at different stages of regeneration using direct organogenesis system. Exogenous spermidine (137.69 μM) in shoot induction medium containing optimal BA concentration (2.22 μM) induced maximum number of shoots (39.02 shoots/explant) compared to BA (2.22 μM) alone. Regenerated shoots elongated well in shoot elongation medium containing GA3 (1.45 μM) and spermine (74.13 μM), and developed profuse roots in root induction medium containing putrescine (62.08 μM). Rooted plantlets were successfully hardened and acclimatized with a survival rate of 92 %. The amenability of the standardized protocol using cultivar PK 416 was tested on four more Indian soybean cultivars JS 90–41, Hara soy, Co1, and Co2 of which PK 416 was found to be the best responding cultivar, with a maximum of 96.94 % shoot induction.  相似文献   

19.
Lack of competence of seedling explants for efficient shoot proliferation in recalcitrant grain legume cowpea restricts its genetic manipulation for crop improvement. This study aimed at establishing a protocol to increase the shoot proliferation efficiency during the regeneration of transgenic cowpea plants. Here, we describe how seedling preconditioning in thidiazuron (TDZ) could stimulate the transformation process (by 3.5-fold), shoot proliferation potential of cotyledonary node (by a factor of fourfold) and accelerate the transgenic shoot regeneration. We investigated the effect of TDZ and 6-benzyladenine (BA) at high dose (5?C20???M) in the induction phase of regeneration by preconditioning seedlings for different durations (2?C6?days) with the aim of improving shoot proliferation competence from cultured explants. Cotyledonary node explants from preconditioned seedlings were cultured on MSB5 medium supplemented with 5???M BA and 0.5???M kinetin for 4?weeks. Best response in terms of maximum shoot proliferation (7.1 shoots per explants), and greatest shoot length (2.6?cm) were obtained with explants derived from seedlings preconditioned in 10???M TDZ for 4?days. This enhanced shoot proliferation ability was maintained through three subsequent 4-week long regeneration passages. On comparison of the transformation rate in absence and presence of seedling preconditioning (in 10???M TDZ for 4?days), a significant enhancement from 0.6 to 2.1% was observed. The promotive effect of seedling preconditioning had a direct beneficial effect on transgenic plant recovery time leading to a reduction of more than 2?weeks. The protocol was found applicable to seven cowpea genotypes.  相似文献   

20.
Summary We have developed a highly efficient two-stage protocol for induction of multiple shoots from single node in vitro shoot tip explants of Decalepis hamiltonii. It was found that phenylacetic acid (PAA) had a synergistic effect on shoot multiplication when treated with N6-benzyladenine (BA). This protocol used PAA for both multiple shoot induction from nodal explants, elongation of primary shoots, and initiation of adventitious shoot formation from primary shoots. Murashige and Skoog medium containing BA (2.22–31.08 μM) and α-naphthaleneacetic acid (0.27–10.74 μM) or PAA (7.34–36.71 μM) was used to initiate shoot formation from nodal explants. The maximum number of shoots per culture was produced on a medium containing 31.08 μM BA and 14.68 μM PAA, while the longest shoot length and nodes were obtained on medium containing 22.2 μM BA and 14.68 μM PAA. Shoots subcultured on MS medium containing 22.2 μM BA and 14.68 μM PAA elongated along with secondary shoot formation. The shoots were rooted on medium containing 9.7 μM indole-3-butyric acid. The plantlets were acclimatized in soil with an 80–90% survival rate under field conditions.  相似文献   

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