In vitro propagation of Rauwolfia micrantha, a rare medicinal plant

Shoot tip and single node explants from young shoots of 1-year old flowering plants of Rauwolfia micrantha Hook. f. were cultured on Murashige & Skoog (MS) medium variously supplemented with 6-benzyladenine (BA) and -naphthaleneacetic acid (NAA). A combination of 13.2 M BA and 2.68 M NAA induced high frequency (77%) formation of up to 3 shoots from each node in 8 weeks. The regeneration of shoot tips from the field-grown plants and in vitro shoots placed horizontally differed. Repeated subculturing of the shoot tips and single nodes at 6-week intervals for over a year in combination of 4.4 M BA and 0.27 M NAA enabled mass multiplication of shoots without any evidence of decline. Rooting of the excised shoots on medium containing 2.6 M NAA was preceded by callus formation. The rooted plants were removed off the callus, hardened off and 80% established in pots. Micropropagated plants displayed uniform morphological, growth, flowering, fruiting and seed germination characteristics.Abbreviations BA 6-benzyladenie - IAA indole-3-acetic acid - IBA indole-3-butyrie acid - 2-ip 2-isopentenyladenine - MS Murashige & Skoog (1962) - NAA -naphthaleneacetic acid     

In vitro propagation of Fibigia triquetra (DC.) Boiss., a rare stenoendemic species

A rapid clonal propagation method for Fibigia triquetra (DC.) Boiss. (Brassicaceae), a rare Croatian stenoendemic species, has been developed. Shoots originated from aseptically germinated seeds were used for culture initiation. The highest multiplication rate of 9.2 shoots per explant was achieved in a 4-weeks-culture period in the third subculture on half strength Murashige and Skoog medium supplemented with 0.5 μM 6-benzylaminopurine and 2.9 μM gibberellic acid. Excised shoots were rooted best with addition of 8.6 μM indole-3-butyric acid on the same basal medium. Rooted plantlets were successfully transferred to potting soil and acclimatized to outdoor conditions. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro propagation of Spilanthes mauritiana DC., an endangered medicinal herb, through axillary bud cultures

Summary Spilanthes mauritiana DC., (Compositae), a East African medicinal herb containing pharmaceutically promising secondary metabolites, has successfully been raised in vitro. We have developed a clonal propagation protocol that uses juvenile plants as starting material. The addition of benzylaminopurine (BA) (1.0 μM) and naphthaleneacetic acid (NAA) (0.1 μM) to the culture medium resulted in maximum shooting response with minimal callusing. Shoots rooted best in vitro in MS medium supplemented with indole-3-acetic acid (IAA; 0.2 μM), and plants that had already developed roots showed better growth, with maximum survival rate, in the greenhouse after an initial hardening.     

In vitro propagation of the medicinal plant Plumbago zeylanica L. Through nodal explants

Summary A protocol for rapid in vitro propagation using nodal explants obtained from 2-yr-old, field-grown medicinal plants of Plumbago zeylanica L. belonging to the family Plumbaginaceae is described. High frequency bud break and fast development of shoots were induced on Murashige and Skoog's basal medium supplemented with 27.2 μM adenine sulfate +2.46 μM indole-3-butyric acid (IBA). Induction of rooting was achieved by transferring the shoots to the same basal medium containing 4.92 μM IBA. Using our protocol from one twig of P. zeylanica (eight responsive nodes per explant shoot) within a period of 5 mo., eight plantlets could be raised. After a hardening period of 4 wk, there was a 90% transplantation success in the field compared to the 60–65% survival of plantlets recorded in the experiments of previous workers. The plantlets derived through in vitro propagation mimic the growth and morphological characteristics of the donor plants.     

In vitro propagation of the Egyptian medicinal plant,Echinops spinosissimus Turra

The in vitro propagation of medicinal species is proving to be one successful approach to addressing the issues raised by increasing global demand, overharvest of wild populations and variability in product quality. In this report we describe a protocol for establishing nodal cultures of an Egyptian medicinal plant, Echinops spinosis-simus Turra and for the induction of regeneration in epidermal peels and leaf explants obtained from the nodal cultures. Kinetin was found to be optimal for induction and proliferation of nodal cultures. Transverse slices of leaf blades produced regenerants resembling somatic embryos in the presence of thidiazuron while regeneration was observed on epidermal peels only when the medium contained elevated auxin concentrations.     

Biomass production of Cymbopogon citratus (D.C.) stapf., a medicinal plant, in temporary immersion systems

Summary In vitro plants of lemon grass were established, starting from shoot apices derived from plants cultivated under field conditions. The effect of the immersion frequency (two, four, and six immersions per day) on the production of biomass in temporary immersion systems (TIS) of 1 liter capacity was studied. The highest multiplication coefficient (12.3) was obtained when six immersions per day were used. The maximum values of fresh weight (FW; 62.2 and 66.2 g) were obtained with a frequency of four and six immersions per day, respectively. However, the values for dry weight (DW; 6.4g) and height (8.97cm) were greater in the treatment with four immersions per day. The TIS used in this work for the production of lemon grass biomass may offer the possibility of manipulating the culture parameters, which can influence the production of biomass and the accumulation of secondary metabolites. We describe for the first time the in vitro production of Cymbopogon citratus biomass in TIS.     

In vitro clonal propagation through mature nodes of Tinospora cordifolia (Willd.) Hook. F. & Thoms.: An important ayurvedic medicinal plant

Summary A protocol was developed for rapid clonal propagation of the important medicinal climber, Tinospora cordifolia, through in vitro culture of mature nodal explants. Shoots were initiated on both Murashige and Skoog (MS) medium and woody plant medium (WPM) supplemented with 2.32 μM kinetin (KIN). Of the two basal media tested, WPM was found to be superior to MS medium for the induction of multiple shoots. Among the cytokinins tested, N⁶-benzyladenine (BA) was more effective than KIN for axillary shoot proliferation. KIN was superior to BA in terms of shoot elongation. An average multiplication rate of 6.3 shoots per explant was obtained with WPM supplemented with 8.87 μM BA. Shoot clumps harvested from this medium were transferred to WPM supplemented with 2.22 μM BA and 4.65 μM KIN for shoot elongation. Elongated shoots were rooted in half-strength MS medium supplemented with 2.85 μM indole-3-acetic acid (IAA). Rooted plantlets were successfully transferred to sand and established with 80% survival.     

In vitro propagation of Leucopogon obtectus Benth. (Epacridaceae)

Micropropagation was achieved with the rare and endangered Western Australian woody shrub Leucopogon obtectus Benth. (Epacridaceae). BA 10M, IBA 0.5M, 1/2 MS salts and various growth factors produced an approximate twelve-fold multiplication rate compared to controls. Micropropagation was not accomplished using auxin-supplemented 1/2 or 1/4-strength MS-based media. However, an average 70% rooting was achieved with only agar/water medium and a high percentage of these rooted plantlets were established in pots containing habitat soil.     

Rapid in vitro propagation of Saussurea lappa, an endangered medicinal plant, through multiple shoot cultures

Summary Rapid micropropagation of Saussurea lappa C. B. Clarke, an endangered medicinal plant endemic in the valley of Kashmir and western Himalayas of northern India, was achieved by culturing shoot tips (0.5–1 cm) of 2-wk-old seedlings on Murashige and Skoog’s medium (MS) supplemented with thidiazuron (TDZ, 0.45 μM). Although callus-free multiple shoots were obtained both on N⁶-benzyladenine- (BA) and TDZ-containing media, TDZ was most effective (90%) in inducing multiple shoots. Shoot tips containing proliferative buds were divided into equal halves and subcultured on MS liquid medium containing 0.225 μM TDZ for further multiplication and elongation. Multiplication of induced shoot buds was more effective when cultured in liquid medium than on agar-solidified medium. Shoots (8–10 cm) developed were rooted in MS medium containing naphthaleneacetic acid (NAA, 1.07 μM). Micropropagated plantlets were successfully transferred to soil after hardening.     

In vitro propagation of a Saccharum officinarum (L.) and Sclerostachya fusca (Roxb.) A. Camus hybrid

Summary Callus induction and plant differentiation were obtained in an intergeneric hybrid of Saccharum officinarum and Sclerostachya fusca. The sub clones showed morphological variation. Chromosome numerical variation was not observed but structural aberrations were noticed in some sub clones. The study indicates the use of tissue culture technique for inducing intergeneric gene transfer in Saccharum hybrids.     

Micropropagation ofTribulus terrestris L., an important medicinal plant

Direct regeneration of shoots and roots through juvenile expiants has been achieved inTribulus terrestris. Cotyledonary leaves along with epicotyl segment from young seedlings were cultured on MS medium containing various concentrations of auxin with cytokinin and glutamine. A combination of 0.2 mgL⁻¹ NAA, 0.5 mgL⁻¹ BAP and 50 mgL⁻¹ glutamine induced high frequency of shoot and root differentiation in 10 weeks. The callus also could be induced on the above medium from the cut end of radical segments. Morphogenic response such as per cent shoot and root differentiation was recorded at regular intervals.     

In vitro culture of common mullein (Verbascum thapsus L.)

Summary Verbascum thapsus L. is a medicinal herb and has been used to treat inflammatory disease, asthma, spasmodic coughs and migraine headaches. Studies were initiated to establish an in vitro culture protocol for V. thapsus. Explants (leaf dises, petioles and roots) were cultured on Murashing and Skoog minimal organics (MSMO) medium with benzyladenine (BA) or kinetin. Best shoot proliferation was obtained from leaf dise and petiole explants at 13.32 μM BA. Leaf dises were cultured on MSMO medium with 13.32 μM BA in combination with naphthalene acetic acid (NAA) or 2,4-dichlorphenoxyacetic acid (2,4-D). More shoot development was obtained with 13.32 μM BA and 5.37 μM NAA. Shoots were transferred to rooting media containing different levels of NAA and 2,4-D. Most of the shoots formed roots on media with 5.37 μM NAA. Plants were transferred to vermiculite and subsequently to potting media and maintained in the greenhouse.     

In vitro propagation of limonium wrightii (Hance) Ktze. (Plumbaginaceae), an ethnomedicinal plant, from shoot-tip, leaf- and inflorescence-node explants

Summary Rapid in vitro propagation of Limonium wrightii (Hance) Ktze. (Plumbaginaceae), an endangered medicinal plant, was achieved by culturing the shoot-tip (primary and lateral), leaf- and influorescence-node explants. MS (Murashige and Skoog, 1962) medium supplemented with 8.87 μMN⁶-benyladenine (BA) and 1.07 μM α-naphthaleneacetic acid (NAA) supported induction of adventitious shoots from the shoot-tip, inflorescence-node and middle and basal parts of leaf explants after 60 d of culture. Adventitious shoots were multiplied by subculturing on MS medium supplemented with BA (2,21–17.75 μM) in combination with NAA (1.07 μM). The percentage of explants forming shoots and the average number of adventitious shoot buds produced per explant were stimulated by increasing the strength (1/4x, 1/2x, 1x, 2x) of the MS medium. Shoots were rooted on MS basal medium with 4.92 μM indole-3-butyric acid. Plantlets with a morphologically normal appearance produced from adventitious shoots were transferred to soil and acclimated in the growth chamber for 1 mo.     

In vitro propagation ofMimosa tenuiflora (Willd.) Poiret,a Mexican medicinal tree

Summary Mimosa tenuiflora (Willd.) Poiret (Leguminosae) was micropropagated throughin vitro culture of axillary buds on Murashige and Skoog (MS) medium. Shoot formation was achieved when the media were supplemented with 0.1 mg.L^–1 IAA + 3 mg.L^–1 KN.In vitro rooting of regenerated shoots was achieved when 0.1 mg.L^–1 KN was combined with 1 mg.L^–1 IBA in the absence of IAA. Ninety-four percent of the rooted plants were succesfully adapted to field conditions and grown in the soil. A total of 180 trees grown under these conditions were obtained over a one-year period.Abbreviations KN (kinetin) - IAA (-indoleacetic acid) - MS (Murashige and Skoog (1962) medium) - IBA (indole-3-butyric acid) - NAA (anaphthaleneacetic acid)     

In vitro propagation of Artocarpus altilis (park.) fosberg (breadfruit) from mature plant material

Summary A micropropagation protocol for Artocarpus altilis (breadfruit, yellow cultivar) using shoot tip explants taken from mature trees is outlined. Cultures were initiated from shoot tip explants (1–2 mm in length) on either N5K or N15K (Margara, 1978) macronutrient formulation, MS (Murashige and Skoog, 1962) micronutrients and vitamins and 6-benzyladenine (BA, 4.4 μM). Single-node explants obtained from shoots formed at the initiation stage were used at the multiplication stage. Multiplication elongation and maintenance were possible on N30NH₄ (Margara, 1978) macronutrients, MS micronutrients and vitamins and zeatin 2.2 μM. Shoot elongation was not enhanced by the inclusion of gibberelic acid at 1.4 μM, 2.8 μM or 14.0 μM, along with zeatin at 2.2 μM, when compared with those shoots cultured on zeatin only. N30NH₄ was found to be superior (with respect to shoot quality) to MS macronutrient formulations at the multiplication and maintenance stages, because the shoots with development were more vigorous than those formed on the other macronutrient formulations mentioned. Zeatin at 2.2 μM yielded 50% more in vitro-formed shoots when compared with BA at 4.4 μM for the same time period. Shoots rooted on hormone-free medium with a success rate of 60%. Regenerated plantlets were hardened with about a 40% success rate.     

In vitro propagation of mature trees of Alnus incana (L.) Moench.

Mature trees of European grey alder (Alnus incana) were micropropagated on a modified MS medium containing 2.5 M BA, 6.2 mM (500 mg l^-1) NH₄NO₃ and 1.5% glucose. Prior to in vitro culture, mature scions were multiplied through grafting and cutting techniques. Shoot tips from cuttings were established in vitro. After six months of culture, shoots were rooted either in vitro or in vivo and plantlets were transferred to greenhouse conditions.     

Clonal propagation of Arnica montana L., a medicinal plant

Summary Micropropagation of Arnica montana L. using Murashige and Skoog (MS) medium supplemented with N⁶-[2-isopentenyl]adenine (2iP), zeatin and α-naphthaleneacetic acid (NAA) in different concentrations does not ensure the formation of a high number of regenerated plants; a maximum of 3.2 neoplantlets per explant were obtained. After 4 wk of culture on medium with zeatin (4.5 μM) and NAA (5.3 μM), plants were 3.06 cm in length. The following step was to improve the clonal propagation of this species. Micropropagation of Arnica montana L., initiated from nodal segments using semisolid media (4 g l⁻¹ agar), was obtained. Explants were inoculated on MS medium supplemented with NAA (5.3 μM), 2iP (5.0 μM), maize extract (1.0 ml l⁻¹), phloroglucinol (0.6 mM) or adenine sulfate (0.2 mM). Only 3 wk after the inoculation, plant multiplication as well as induction of roots were obtained, the optimal variant being that containing NAA (5.3 μM), 2iP (5.0 μM) and maize extract (1.0 ml l⁻¹). Six weeks after the inoculation plants were transferred to Perlite, with 80% plant survival being obtained. By isoesterase pattern we concluded that we have obtained the clonal propagation of Arnica montana, because the pattern of several individuals belonging to different clones was the same. Only one region with esterase activity that is present in all individuals has been identified.     

In vitro micropropagation of Primula scotica: a rare Scottish plant

A simple micropropagation method is reported for Primula scotica, a rare plant, endemic to the North of Scotland. The technique involves the clonal proliferation of seed-derived plantlets on either hormone free tissue culture medium or on medium containing benzyl amino purine and indole acetic acid. Average multiplication rates of 4–6 were obtained for plants grown on plant growth regulator supplemented medium. The micropropagation method was applied to four different clones of P. scotica and clonal differences were observed in relation to media type. Some plants from certain clones did display hyperhydricity, however, this was circumvented by using frequent sub-culturing intervals and transferring the plants to hormone-free medium. Plantlets rooted on both media types and displayed normal, true-to-type rosette morphology. The cultures did not callus and development proceeded via shoot and root production only. The in vitro-grown plants could be transferred to ex vitro conditions and a range of growth substrates were assessed for their efficacy in supporting ex vitro growth, with a view to developing longer-term strategies for the transfer and reintroduction of micropropagated P. scotica plants into natural habitats. The simple method described in this paper may offer the potential of being applied to other endangered Primula spp.     

Comparative studies of cytokinins on in vitro propagation of Bacopa monniera

A mass in vitro propagation system for Bacopa monniera (L.) Wettst. (Scrophulariaceae), a medicinally important plant, has been developed. A range of cytokinins have been investigated for multiple shoot induction with node, internode and leaf explants. Of the four cytokinins (6-benzyladenine, thidiazuron, kinetin and 2-isopentenyladenine) tested thidiazuron (6.8 μM) and 6-benzyladenine (8.9 μM) proved superior to other treatments. Optimum adventitious shoot buds induction occurred at 6.8 μM thidiazuron where an average of 93 shoot buds were produced in leaf explants after 7 weeks of incubation. However, subculture of leaf explants on medium containing 2.2 μM benzyladenine yielded a higher number (129.1) of adventitious shoot buds by the end of third subculture. The percentage shoot multiplication (100%) as well as the number of shoots per explant remained the high during the first 3 subculture cycles, facilitating their simultaneous harvest for rooting. In vitro derived shoots were elongated on growth regulator-free MS medium and exhibited better rooting response on medium containing 4.9 μM IBA. After a hardening phase of 3 weeks, there was an almost 100% transplantation success in the field. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro propagation ofPhebalium equestre andPhebalium hillebrandii (rutaceae)

Summary The endangeredPhebalium equestre D. A. Cooke and the rarePhebalium hillebrandii J. H. Willis were propagated in vitro using shoot tips and nodal segments as explants. For each species, shoot proliferation was initiated on de Fossard MZZM (Medium levels of minerals, Zero auxins, Zero cytokinins and Medium levels of sucrose, growth factors, and amino acids) medium supplemented with 1 μM benzyladenine. ExcisedP. equestre shoots initiated roots when cultured on MZZM medium containing 60 μM 2,4-dichlorophenoxyacetic acid, whileP. hillebrandii shoots required LZZL (Low levels of minerals, Zero auxins, Zero cytokinins and Low levels of sucrose, growth factors, and amino acids) medium containing 10 μM 2,4-D for maximal root initiation. Both species required transfer to MZZM medium without growth regulators after 2 wk to allow root initials to develop and grow. Plantlets were successfully transferred to soil with 80% survival after 2 mo.