Callus induction and shoot regeneration in Sempervivum tectorum

Leaf and shoot explants of Sempervivum tectorum L., taken from 14- and 30-day-old plants germinated in vitro, have been studied by using Murashige-Skoog and White basal media with cytokinins (benzyladenine, kinetin) and auxins (indoleacetic acid, naphthaleneacetic acid, indolebutyric acid) in various concentrations. Explants taken from 14-day-old plants died but 30-day-old leaves and shoots produced yellow and soft, as well as green and hard calluses on Murashige-Skoog medium with 4.4–8.8 M benzyladenine and 0.57 M indoleacetic acid. Shoot organogenesis was induced from green, hard callus in a medium with 2.2 M benzyladenine plus either 1.1 M indoleacetic acid or 2.5 M indolebutyric acid. Whole plants were grown on Murashige-Skoog medium without plant growth regulators. On the other hand, White medium was not suitable for raising Sempervivum tectorum in vitro.Abbreviations BA benzyladenine - IAA indoleacetic acid - IBA indolebutyric acid - MS Murashige-Skoog - NAA napthaleneacetic acid - W White     

In vitro axillary shoot proliferation and somatic embryogenesis of yellow pitaya Mediocactus coccineus (Salm-Dyck)

Yellow pitaya (Mediocactus coccineus) seeds were sown on Murashige and Skoog (1962) mineral salt medium. After germination, epicotyls were placed on media enriched with a combination of naphthaleneacetic acid (NAA) (0.05, 0.27 or 0.54 M) and benzyladenine (BA) (2.2 or 4.4 M). The apical tip was excised from half of the shoots and the other half were kept intact. Different values for proliferation rate, shoot length and thickness were observed on each medium. The cotyledons and roots were placed on MS medium supplemented with NAA (2.7 or 5.4 M) and embryogenic calluses were formed. Somatic embryos were induced on these media and then they normally developed on a growth regulator-free medium.Abbreviations BA benzyladenine - MS Murashige and Skoog - NAA -naphthalenacetic acid     

Micropropagation of parsley through axillary shoot proliferation

A micropropagation protocol of parsley,Petroselinum crispum (Mill.) Nyman (curled type) has been developed. Surface-sterilized axillary buds cultured on Murashige and Skoog medium supplemented with benzyladenine, kinetin, or thidiazuron developed axillary shoots (rosettes). Kinetin resulted in only a low proliferation rate. The concentrations of thidiazuron or benzyladenine that were optimal for shoot proliferation, resulted in shoots with a low capability to root. During the rooting treatment, these shoots showed wilting signs. Rooting was increased significantly by using a two-week inductive stage with 2.5 M naphthaleneacetic acid directly followed by acclimatization. Two proliferation media (5 M benzyladenine and 0.5 M naphthaleneacetic acid or 5 M kinetin and 2.5 M naphthaleneacetic acid) resulted in moderate proliferation but produced shoots that were easy-to-root. These media have been tested by repeated axillary proliferation on the same medium. The medium with 5 M benzyladenine and 0.5 M naphthaleneacetic acid was optimal.Abbreviations BA 6-Benzyladenine - IBA Indole-3-butyric acid - MS Murashige & Skoog - NAA -Naphthaleneacetic acid     

Enhancement of shoot regeneration from cotyledon explants of Brassica rapa ssp oleifera through pretreatment with auxin and cytokinin and use of ethylene inhibitors

The presence of benzyladenine or naphthaleneacetic acid in seed germination medium markedly enhanced subsequent shoot regeneration from the base of the excised cotyledon explants of Brassica rapa cv. Horizon. Cotyledon explants from younger seedlings (3 or 4-day old) produced more shoots than those from older seedlings. Addition of the ethylene inhibitor aminoethoxyvinylglycine (1.0 M) to the regeneration medium improved shoot regeneration three fold.Abbreviations AVG aminoethoxyvinylglycine - BA benzyladenine - MGBG methylglyoxal-bisguanylhydrazone - MSBN ms (murashige & skoog 1962) medium supplemented with 4.4 m BA & 5.4 m NAA, 2% sucrose - NAA naphthaleneacetic acid     

Adventitious in vitro plantlet formation from immature floral stems of Crinum macowanii

Adventitious shoots and plantlets were regenerated in vitro from floral stem explants of Crinum macowanii (Bak.) (bush lily). The length (age) of the floral stem as well as the orientation and position of the explant disc in the floral stem were the most important factors affecting shoot regeneration. The highest number of shoots were regenerated when immature floral stems of 70–100 mm were used as starting material, using the middle or basal parts of the stem, and orientating the discs with their proximal ends on the medium. Combinations of kinetin (4.65 M) and either indoleacetic acid (0.57 M) or naphthaleneacetic acid (0.54 M), or a combination of benzyladenine (4.44 M) and 2,4-dichlorophenoxyacetic acid (0.45 M) resulted in the highest numbers of shoots being regenerated. Although a slight degree of callus formation was noticed on the cut-edges of the discs, shoot formation did not occur via callus, but directly from the floral stem epidermis. Unrooted shoots were rooted on MS-medium containing 0.17 M sucrose.Abbreviations BA benzyladenine - IAA indoleacetic acid - IBA indolebutyric acid - NAA naphthaleneacetic acid - 2,4-d 2,4 dichlorophenoxyacetic acid     

In vitro culture ofXanthium strumarium (Cocklebur)

Xanthium strumarium L. was micropropagated by rooting shoots proliferated from shoot-tip explants. The best shoot proliferation was obtained from explants growing on Murashige and Skoog medium supplemented with 4.4 to 8.9 M benzyladenine (BA) and 1.1 to 2.1 M naphthaleneacetic acid (NAA). The micropropagated plants were transferred to potting media and maintained under high humidity conditions in the greenhouse. The media that produced best shoot proliferation from shoot-tip explants also produced the most callus from hypotocotyl, cotyledon and shoot-tip explants, whereas more callus was produced on leaf explants with a lower BA concentration (1.1 M) and 1.1 M NAA.Abbreviations BA benzyladenine, 2 4-d-2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - NAA naphthaleneacetic acid - MS Murashige and Skoog Technical contribution No. 3319 of the South Carolina Agricultural Experiment Station, Clemson University.     

Plant regeneration from nucllar tissues of Aegle marmelos through organogenesis

A protocol for organogenesis from nucellar explants excised from fertilized ovules of immature fruits of Aegle marmelos Corr. was developed. Adventitious buds were initiated on Murashige and Skoog's (MS) medium containing various combinations of 6-benzyladenine (BA), -naphthalene-acetic acid (NAA), 3-indoleacetic acid and gibberellic acid. Medium containing 4.4 m BA and 2.7 M NAA produced the maximum number of adventitious buds per explant. Shoots were elongated by transferring explants with shoot buds to medium with a low concentration of BA (0.44 M). Rooting of in vitro-regenerated shoots was obtained in half-strength MS medium with 4.9 M indole-3-butyric acid. This is the first report of plant regeneration from nucellar explants of A. marmelos.Abbreviations BA benzyladenine - IAA indoleacetic acid - IBA indolebutyric acid - NAA naphthaleneacetic acid - GA₃ gibberellic acid     

Adventitious shoot formation and plant regeneration from tissues of tomatillo (Physalis ixocarpa Brot.)

Cultured hypocotyl explants of tomatillo (Physalis ixocarpa Brot.), were evaluated with regard to their morphogenic responses to combinations of benzyladenine (BA, 0–5 M) with either naphthaleneacetic acid (NAA, 0–50 M) or 2,4-dichlorophenoxyacetic acid (2,4-D, 0–50 M). The induction of shoots or roots was dependent on the cytokinin/auxin combination.Hypocotyl explants failed to form shoots when they were grown on media containing either a cytokinin or an auxin alone. The highest frequency of shoot formation was observed on media containing 12.5–25 M BA and 5 M NAA. Likewise the highest frequency of root formation was observed on media supplemented with 1 M BA and 1 M NAA. Complete plants were regenerated and transferred to soil, where they reached maturity.     

Rapid propagation of tuna (Opuntia ficus-indica) and plant establishment in soil

Explants from young joints of mature plants of tuna (Opuntia ficus-indica Mill.) were cultured on Murashige and Skoog (MS) medium containing 8.8 M benzyladenine (BA) and 0.5 M naphthaleneacetic acid (NAA). Shoots produced were utilized as secondary explants. Each shoot was cut longitudinally from apex to base into two explants, and some of these explants were cut transversely into proximal and distal explants. The size and number of shoots produced was affected by size and position of the explant within its source. The shoots were rooted in vitro or ex vitro and plants were successfully established in soil from both rooting methods.Abbreviations AC activated charcoal - BA benzyladenine - IBA indolebutyric acid - MS Murashige & Skoog (1962) medium - NAA naphthaleneacetic acid     

Thidiazuron stimulates shoot organogenesis and somatic embryogenesis in white ash (Fraxinus americana L.)

Immature and mature nonstratified seeds of white ash (Fraxinus americana L.) were dissected transversely and 2/3 of each seed was placed onto agar-solidified Murashige and Skoog medium. Adventitious buds, shoots, and somatic embryos formed on callus, cotyledons, and hypocotyls of the resulting seedlings. Shoot organogenesis was induced on explants cultured on medium with 10 M thidiazuron but not on explants on media with benzyladenine (BA) or isopentenyladenine. Not all seed sources were equally capable of shoot organogenesis and embryogenesis. Atypical of adventitious regeneration of other woody plants, mature seed explants of white ash were more organogenic with shoots that elongated better than explants from immature seeds. Somatic embryogenesis was observed in cultures where mature seeds were first cultured for 4 weeks on a medium containing 10 M adenine 2,4-dichlorophenoxyacetic acid in combination with 0.1 and 1.0 M thidiazuron, followed by transfer to a medium containing 0.05 M 6-benzyladenine and 0.5 M naphthaleneacetic acid. Adventitious shoots and epicotyls from both seedlings and germinated somatic embryos were rooted under intermittent mist and acclimatized to the greenhouse.Abbreviations BA 6-benzyladenine - 2,4-d 2,4-dichlorophenoxyacetic acid - IBA indolebutyric acid - 2iP isopentenyladenine - NAA naphthaleneacetic acid - TDZ thidiazuron-N-phenyl-N-1,2,3-thiadiazol-5-ylurea - WPM woody plant medium     

In vitro organogenesis of elephant apple (Feronia limonia)

Elephant apple (Feronia limonia L.). was micropropagated on MS medium containing 4.4 M benzyladenine and 4.6 M kinetin using cotyledon explants taken from in vitro-grown seedlings. Adventitious buds formed on the cotyledon developed into shoots that were rooted in half-strength MS medium containing 0.57 M indoleacetic acid and 0.49 M indolebutyric acid. Plants were successfully established in soil.Abbreviations BA 6-benzyladenine - IAA 3-indoleacetic acid - IBA 3-indolebutyric acid - MS Murashige & Skoog     

Micropropagation of Lavandula latifolia through nodal bud culture of mature plants

Cultures of Lavandula latifolia Medicus were established from axillary buds of mature field-grown plants. Explants were initially cultured on media with two different macronutrient combinations and benzyladenine or kinetin added either individually or with naphthaleneacetic acid. Subsequently, explants were subcultured in Murashige and Skoog medium supplemented with 20% coconut milk, 0.57 M indoleacetic acid and 8.88 M benzyladenine. Shoot proliferation from axillary buds was not affected by seasonal fluctuations in the stock plants but depended on the macronutrient composition and on the type and concentration of cytokinin tested. Best results were obtained in explants initially cultured in media with Murashige and Skoog constituents and supplemented with 5 M benzyladenine. In vitro-grown shoots were used to induce multiple shooting by transferring them to subculture medium. Shoots were rooted on Murashige and Skoog medium with macronutrients at half-strength. Plantlets were transferred to soil and grown to maturity.     

In vitro plant regeneration from callus derived from root explants of Lathyrus sativus

Protocols have been developed for the in vitro production of plants from callus derived from root explants of Lathyrus sativus cv. P-24. Callus and shoot regeneration were achieved only in MS medium supplemented with 10.7 M naphthaleneacetic acid and an increased concentration of kinetin (0.9 M for 14 days to 1.4 M for 18 days) during callusing. The shoots obtained rooted in 1/2 MS supplemented with 0.5 M indolebutyric acid. During the year plants have been regenerated several times. The requirement for growth regulators is very specific and narrow.Abbreviations IAA indoleacetic acid - IBA indolebutyric acid - NAA naphthaleneacetic acid - BA benzyladenine     

In vitro clonal propagation of tea (Camellia sinensis (L.) O. Kuntze)

A system for in vitro clonal propagation has been developed in tea plants. Shoots obtained from primary explants were induced from terminal buds and axillary buds of mature field-grown plants. Cultures were initiated from both types of explants on Murashige and Skoog (MS) medium supplemented with 10% coconut milk (CM), 200 mg l^-1 of yeast extract (YE), 1.4 M indoleacetic acid (IAA) and 17.8 M benzyladenine (BA). The shoot tips were multiplied on 1/2 strength MS medium containing 10% CM, 2.9 M IAA and 17.8 M BA. The larger shoots were separated after multiplication and rooted on 1/2 MS medium supplemented with 11.4 M ascorbic acid and 34.5 M indolebutyric acid (IBA). A pretreatment of the plants with an aqueous solution of 493 M IBA greatly increased the frequency of rooting. More than 60% of the rooted plants have been transferred to soil successfully.Abbreviations BA benzyladenine - IAA indoleacetic acid - IBA indolebutyric acid - YE yeast extract - CM coconut milk - MS Murashige and Skoog medium (1962)     

Regeneration of Elaeagnus angustifolia from leaf segments of in vitro-derived shoots

Shoot regeneration was achieved from in vitro-produced leaves of Elaeagnus angustifolia L. Half-leaf explants from the terminal part of the shoot produced more shoots than explants from the basal part of the in vitro-derived shoots on agar-solidified WPM medium supplemented with 1 M benzyladenine (BA). In liquid medium of the same formulation, compact shoots that did not elongate were formed on the explants. Leaf cross-section explants (1 mm thick) produced shoots both on solid and liquid medium with 1 M BA, whereas again compact shoots were formed with 10 M BA. Further shoot development on these explants was promoted by their transfer to fresh solid medium containing 1 M BA and 1 M gibberellic acid (GA₃).Abbreviations BA benzyladenine - GA₃ gibberellic acid - WPM woody plant medium     

In vitro micropropagation of Piper longum – an important medicinal plant

Efficient and rapid tissue culture systems were developed for Piper longum, an important medicinal plant, through shoot tip multiplication and direct regeneration. Multiple shoots were induced from shoot tips cultured on agar-based Murashige and Skoog (MS) medium containing 4.44–22.19 M benzyladenine (BA) and 4.64–13.9 M kinetin (K). Maximum number of shoots were induced with 8.9 M BA and 4.64 M K. Adventitious shoot regeneration from leaf segments was achieved on MS containing 3.6–22.19 M BA along with 3.31–12.4 M picloram (P). Shoot differentiation occurred directly from the leaf bases without intermediale callus formation. Maximum shoot buds were obtained on MS medium with 17.76 M BA and 8.28 M P. Elongated shoots were separated and rooted in MS supplemented with 2.46 M indole butyric acid (IBA). Plantlets, thus developed were established in soil.     

Regeneration of plants from callus tissue of Aeschynomene spp. (Leguminosae)

Plants were regenerated from leaflet-derived callus of Aeschynomene sensitiva, A. americana and A. villosa. Explants were induced to form callus when aseptically cultured on Murashige and Skoog medium solidified with 0.8% agar and containing 0.5 or 0.05 M naphthaleneacetic acid and 4.4 or 13.3 M benzyladenine. Shoot regeneration was readily achieved. Roots were induced when shoots were transferred to medium devoid of growth regulators or with 0.05, 0.5 or 5.4 M naphthaleneacetic acid. Plantlets were successfully transplanted to soil. Callus from A. falcata failed to regenerate shoots. Explants from leaflets of A. fluminensis did not produce callus when cultured in vitro.Abbreviations BA benzyladenine - MS Murashige and Skoog (1962) medium - NAA naphthaleneacetic acid     

Micropropagation of the Mediterranean species Viburnum tinus

In vitro propagation of the Mediterranean species Viburnum tinus L. was established from an outdoor-grown shrub. Two standard macrosalt formulations (Margara N30K and Murashige and Skoog), a range of benzyladenine and sucrose concentrations were tested for their effect on shoot multiplication. The cytokinin concentration was the most important factor affecting shoot multiplication. The highest shoot multiplication rate was obtained from single-node explants cultured on Murashige and Skoog medium supplemented with 4.4 M benzyladenine. Cytokinin concentration and an interaction of macrosalts and benzyladenine influenced shoot length on the multiplication stage: best shoot growth was observed on MS medium containing 1.1 M benzyladenine. In addition, sucrose concentrations of 87.6–146.0 mM gave the highest multiplication rates and improved shoot growth. Following a shoot ellongation stage, single shoots were rooted on media containing naphtaleneacetic acid (1.3–5.4 M). Although enhanced in vitro rooting was obtained on media containing 5.4 M naphtaleneacetic acid, reducing the auxin concentration to 1.3 M during the in vitro rooting stage improved acclimatisation frequency and further plant growth in a horticultural substrate.     

Morphogenesis and plant regeneration from tissue cultures of Jatropha curcas

Techniques for the regeneration of Jatropha curcas L. from various explants have been developed. Regeneration from hypocotyl, petiole and leaf explants was evaluated on a range of concentrations of zeatin, kinetin and N⁶ benzyladenine (BA) either singly or in combination with indole-3-butyric acid (IBA). Higher regeneration from hypocotyl and petiole explants was obtained on BA with IBA than on zeatin- or kinetin-supplemented media. Leaf discs from the third expanding leaf exhibited higher regeneration potential than those from the fourth leaf. Independent of the explant type, direct adventitious shoot bud induction was recorded highest on MS medium with 2.22 M BA and 4.9 M IBA. Although the same BA concentration but with reduced IBA concentration (0.49 M) proved effective in callus mediated regeneration from hypocotyl and leaf explants, the petioles required lower concentrations of the two growth regulators (0.44 M BA and 0.49 M IBA). Regenerated shoots could be rooted on growth regulator-free gelled full-strength MS medium. Following simple hardening procedures, the in vitro-raised plants could be transferred to soil and grown to maturity in the field.Abbreviations BA N⁶ benzyladenine - IAA indole-3-acetic acid - IBA indole-3-butyric acid - MS Murashige & Skoog's (1962) medium - NAA -naphthaleneacetic acid     

Axillary shoot induction and plant regeneration in Plantago ovata Forssk

Axillary shoot induction and plant regeneration were obtained in Plantago ovata. The optimum medium for inducing axillary shoots was Murashige & Skoog (MS) medium [5] supplemented with 4.6 M kinetin and 0.05 M NAA. Rooting of shoots was best on half-strength MS medium containing 5.0 M IBA and 0.05 M kinetin. The regenerated plants were similar to the control plants in karyotypic and phenotypic details.