Micropropagation and accumulation of essential oils in wild sage (Salvia fruticosa Mill.)

A protocol for in vitro propagation of the wild three-lobed sage (Salvia fruticosa Mill.) (Synonym, Salvia triloba L.) was developed. Shoot tips were excised from in vitro seedlings and established on MS, Nitch and Nitch (NN), or B5 medium. For shoot proliferation, in vitro nodal and apical explants were cultured on MS medium containing 0.25–2 μM 6-benzylaminopurine (BA), 6-furfurylaminopurine (kinetin), or thidiazuron (TDZ). Proliferated microshoots were rooted on MS medium supplemented with 2.7–11.4 μM indole-3-butyric acid (IBA), indole-3-acetic acid (IAA), or α-naphthaleneacetic acid (NAA). Results indicated that shoots established at 100% regardless of media type, however, shoot height, nodes per shoot, and leaf number were highest for explants established on MS medium compared to NN or B5. Number and height of proliferated shoots, nodes per shoot, and leaf number were highest for nodal explants cultured on a medium containing 0.75 μM BA. Microshoots cultured on a medium supplemented with 2.7 μM IBA exhibited the highest rooting percentage compared to those cultured with IAA or NAA. Essential oil composition in microshoots and shoots of greenhouse-grown plants was determined by gas chromatography/mass spectrometry. The major essential oils detected in both plant materials were α-pinene, 1,8-cineole, camphor, and borneol. No α-thujone or β-thujone was detected. The content of essential oils, camphor, and borneol were higher in the microshoots than in shoots of greenhouse-grown plants.     

In vitro micropropagation from plumular apices of Turkish cowpea (Vigna unguiculata L.) cultivar Akkiz

Multiple shoot formation from the plumular apices excised from mature embryos of cowpea cv. Akkiz was obtained after pulse treatment with 10 mg/l BAP for 5 days followed by culture on MS medium containing 0.25, 0.50, 0.75 and 1.00, 1.25 mg/l BAP – with or without 0.10 mg/l NAA. Callus induction and shoot regeneration was recorded on all cultures containing BAP with or without NAA. However, inclusion of 0.1 mg/l NAA had positive effect on callus diameter and shoot length. Maximum mean number of 7.11 shoots per explant were obtained on MS medium containing 1.00 mg/l BAP. Longer shoots were recorded on MS medium containing various concentration of BAP+ 0.1 mg/l NAA compared to those containing various concentrations of BAP singly. All shoots cultured on MS medium containing 1 mg/l BAP were rooted on MS medium containing 0.50 mg/l IBA. Rooted plants were acclimatized at room temprature in soil contained in pots. All plants flowered and set seeds in the greenhouse after 3 months.     

Somatic embryogenesis in cell suspension cultures of Prunus persica (L.)

Cell suspension cultures were derived from adventitious somatic embryos induced on cotyledons of rescued peach embryos. Embryogénie calli were induced and established on modified MS medium supplemented with 2,4-D, BAP, KN and inositol. Development of embryos during suspension cultures was identified by growth pattern and by histological and cytological examination, using acetocarmine stain. More embryogenic calli were produced using 2,4-D (5 (µM) than NAA. A gradual reduction of 2,4-D increased the recovery of globular embryos. Heart-stage embryos were developed on high-nitrogen salt medium, with added Ca(N03)2 (1000 mg I"1) and 6% sucrose. Somatic embryos turned green and sometimes red under white light. Embryo viability was highest when subculturing every 14 days. Viability of cells and differentiating embryos was assessed, microscopically, with Alexander’s stain. Viable embryos reacted pink to red while non- viable embryos reacted green to blue. Embryogenic cell suspension cultures were maintained for over ten months by regular subculturing after two weeks on modified MS medium with low 2,4-D, BAP and KN.     

红龙草叶片的组织培养及其植株再生

 建立了红龙草叶片再生体系。叶片外植体在培养基MS + 6-BA 1.0 mg/L + 4-PU 1.0 mg/L +NAA 0.1 mg/L上形成浅绿色愈伤组织, 20 d后愈伤组织诱导率达100%。约45.31%的愈伤组织在添加6-BA 1.0 mg/L和NAA 0.4 mg/L的MS培养基上分化出紫红色的不定芽, 约6%的愈伤组织在该培养基上产生出细小叶片和绿色变异幼芽。所产生的紫红色不定芽在1/2MS +NAA 0.4 mg/L的培养基上可全部生根,长成完整植株。再生植株的移栽成活率达85%以上。     

Multiple shoot regeneration in seed-derived immature leaflet explants of peanut (Arachis hypogaea L.)

A protocol was developed for organogenesis from immature leaflet explants derived from mature seeds of peanut. Immature leaflets pre-incubated on MS medium supplemented with 13.32 μM BAP + 4.95 μM NAA for 7 days, turned green and enlarged. The enlarged green leaflets produced multiple shoot buds after 1–2 cycles of sub-culture on MS medium supplemented with 13.32 μM BAP. Three cycles of shoot buds on the elongation medium (13.32 μM BAP) produced 6.17 ± 0.47 elongated shoots per explant. The shoot bud formation was genotype independent. All elongated shoots rooted on the medium containing 4.95 μM NAA. The complete protocol gave efficient (>81%) direct organogenesis, leading to the development of plantlets within 4 months.     

In vitro embryo germination and proliferation of pistachio (Pistacia vera L.)

In vitro development of isolated embryos and axillary bud proliferation were studied in Pistacia vera L. Different regulator-free nutrient media were compared to determine the effects of the mineral solution, agar and sucrose concentrations on seedling development from mature embryos. Nutrient-rich MS [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tabacco tissue cultures. Physiol. Plant. 15, 473–479] and DKW [Driver, J.A., Kuniyuki, A.M., 1984. In vitro propagation of Paradox walnut rootstock. HortScience 19, 507–509] mineral solutions were more efficient for the development of aerial parts than nutrient-poor KN [Knop, W., 1884. Bereitung einer concentrierten nährstofflosung für pflanzen. Landwersuhssat 30, 292–294] and WT [Withe, P.R., 1936. Plant tissue cultures. Bot. Rev. 2, 419–437] solutions. Reducing the agar concentration enhanced fresh matter production and balanced seedling development. When tested at different concentrations, sucrose was found to orient mature embryo development, with the best results obtained at concentrations of 2–4%, whereas high concentrations (6 and 12%) mainly inhibited elongation of the aerial parts. Plantlets obtained previously from in vitro cultured embryos were propagated by axillary budding. High bud proliferation (six shoots per explant) was achieved when using 17.8 μM benzyladenine (BA) combined with 0.5 μM indole-3-butyric acid (IBA). The addition of 2.9 μM gibberellic acid (GA₃) to the propagation medium did not improve axillary shoot yields and on average, media with GA₃ produced 2.3–2.6 elongated stems per cultured explant. Shoots were rooted in vitro in half-strength MS medium containing 12.3 μM IBA.     

Direct and callus-mediated regeneration of Curcuma soloensis Valeton (Zingiberaceae) and ex vitro performance of regenerated plants

Protocols are outlined for the regeneration of Curcuma soloensis, an attractive tropical ornamental plant, from young vegetative bud explants. We used both direct and callus-mediated regeneration techniques to produce material suitable for mass propagation and the development of transgenic plants. During direct plantlet propagation, the presence of thidiazuron (TDZ) in the growing medium induced more than three times as many shoots as 6-benzylaminopurine (BA), with a mean of 18.7 shoots per explant on MS medium containing 2.5 μM TDZ compared to 5.0 shoots with 40 μM BA. Subsequently, the shoots rooted readily on MS basal medium that was free of plant growth regulators. During indirect plantlet regeneration, TDZ combined with BA and 2,4-dichlorophenoxyacetic acid (2,4-D) had significant effects on embryogenic callus induction and multiplication. The frequency of callus formation was 91.1% for explants cultured on MS basal medium supplemented with 2.5 μM TDZ, 2.0 μM BA and 1.2 μM 2,4-D. On average 7.1 shoots were produced per callus mass cultured on MS medium supplemented with 2.5 μM TDZ, 9.0 μM BA and 1.2 μM naphthaleneacetic acid (NAA). Regenerated shoots were transferred to MS medium supplemented with 2.5 μM TDZ, to produce multiple shoots. In vitro cultured plantlets readily acclimatized to greenhouse conditions, showing 100% survival rates in a sphagnum, perlite and sand (1:1:1) medium. These plants were transplanted into pots or planted in the field. The ex vitro acclimated plants grew vigorously and produced showy inflorescences 5–6 months after planting. The high-frequency of shoot multiplication and rapid flowering of tissue-cultured plants indicate that C. soloensis has great potential in the floricultural market.     

Influence of medium composition and vessel ventilation on in vitro propagation of Phillyrea latifolia L.

Micropropagation of Phillyrea latifolia L. a wild species present in Mediterranean coastal areas having drought and salt tolerance was performed using explants from adult plants. Shoots were induced from nodal explants on the Rugini’s initial medium (IM). Then these were proliferated on either Rugini olive medium (OM) or Linsmaier and Skoog (LS) medium, each supplemented with 2.22 μM 6-benzylaminopurine (BA) or 4.56 μM zeatin (Z). Rooting (66.1±11%) was induced on shoots grown in perlite soaked with half-strength Rugini olive proliferation medium (OMr) containing 2.69 μM α-naphthaleneacetic acid (NAA) and 160 mg l⁻¹ putrescine. Both shoot multiplication and rooting were performed using Magenta^® GA-7 (Sigma) vessels either non-permeable or permeable to gas exchanges. Contamination (about 40%) was observed during the first five passages notwithstanding the addition of cefotaxime to the culture medium, but a high proliferation rate (90%) of explants provided enough healthy plant material. The highest shoot proliferation was observed on LS medium and zeatin whereas the presence of the ventilated filters reduced fresh weight of explants growing on LS media and did not affect shoot growth on OM media. During rooting, the use of ventilated vessels in comparison with the closed ones enhanced development of roots, and doubled the dry weight of plantlets. The vessel ventilation combined with the artificial substrate (perlite) was beneficial for in vitro acclimatization of rooted Phillyrea plantlets.     

In vitro propagation of Pistacia vera L. from seedling tissues

Proliferating shoot cultures were established from shoot tips and nodal bud segments excised from seedlings germinated aseptically and cultured on Murashige and Skoog medium supplemented with BAP plus NAA. Shoot tip necrosis occurred in some cultures. Cultured shoots were rooted in vitro using MS medium (half strength macronutrients) containing IBA for root initiation, followed by subculture onto hormone-free medium for root development. Rooted shoots were readily established in peat-based compost.     

Establishment of efficient regeneration protocol from leaf explants of Iris pumila shoots cultured in vitro

An efficient plant regeneration protocol via somatic embyogenesis by leaf base culture of in vitro grown Iris pumila shoots was developed. Induction of embryogenic calli was achieved on MS media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D), kinetin (4.5 μM, each) and some additives (L-proline, casein hydrolysate, adenine sulphate and tyrosine). Further differentiation of embryogenic calli was achieved on MS hormone-free media, and on media supplemented with either BAP (4.5 μM) or BAP + zeatin (4.5 and 0.2 μM, respectively), which allowed somatic embryos, as well as shoot-like structures to form. Fully developed somatic embryos germinated on an MS hormone-free medium. An anatomical study confirmed that shoot-like structures represented early germinating stages of somatic embryos. Acclimatization of plants derived from somatic embryos was 64% after 1 year and no morphological variation was observed.     

Callus induction and plant regeneration in Cardiospermum halicacabum Linn. an important medicinal plant

Cardiospermum halicacabum Linn. is an important medicinal twining herb belonging to the family sapindaceae. A method for rapid micropropagation of C. helicacabum through plant regeneration from leaf and nodal explant derived calli has been developed. The nodal and leaf segments were cultured on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D; 0.5–9 μM) for callus induction. Callus production was highest at 5 μM 2,4-D where 96 and 90% of cultured leaf and nodal cuttings produced callus, respectively. The viable calli were maintained at reduced concentration of 2,4-D (2 μM). These calli were transferred to MS medium supplemented with various concentrations of 6-benzyladenine (BA; 2–10 μM) or kinetin (2–10 μM) alone or in combination with indole 3-acetic acid (IAA; 0.2–1.0 μM) for shoot regeneration. The addition of low concentrations of IAA into BA or kinetin containing medium significantly increased the frequency of shoot regeneration in both nodal cuttings and leaf-derived calli. The highest number of adventitious shoots (28 per callus) formed at 8 μM Kin and 0.5 μM IAA. For rooting of the shoots, half-strength MS medium supplemented with different concentrations of indole 3-acetic acid, indole 3-butyric acid (IBA) and (alpha)-naphthalene acetic acid (NAA) 1–5 μM was tried. The optimal result was observed on half-strength MS medium supplemented with 2.5 μM IBA, on which 91% of the regenerated shoots developed roots with an average of 4.2 roots per shoot within 45 days. The in vitro raised plantlets were acclimatized and transferred to soil with 90% success. This in vitro propagation protocol should be useful for conservation as well as mass propagation of this medicinal plant.     

扎米莲( Zamioculcas zamiifolia) 叶片的植株再生

 建立了从扎米莲叶片直接再生植株的有效方法。结果表明, 扎米莲叶片外植体在仅加6-BA 或NAA 或2 ,4-D 的培养基中培养8 周后都不能产生幼芽; 但在含不同浓度6-BA (1.0～2.0 mg/L) 和NAA(0.02～0.2 mg/L) 组合的MS 培养基上培养3 周后开始产生幼芽, 其幼芽分化的最佳培养基为MS + 6-BA 2.0 mg/L + NAA 0.02 mg/L。再生芽在添加IBA 0.5 mg/L 的MS 培养基中生根。     

Rapid in vitro multiplication and conservation of Garcinia indica: A tropical medicinal tree species

A simple and efficient method has been developed for rapid regeneration of plantlets via adventitious bud differentiation on mature seeds of Garcinia indica (Thouars) Choisy, a medicinally important facultative apomictic tropical tree species. High frequency direct shoot proliferation was induced in seed segments cultured on Murashige and Skoog's medium supplemented with cytokinins (BAP, kinetin and TDZ) alone and in combination with auxin (NAA). Amongst the various combinations used, BAP proved to be the most effective. Multiple shoots formed within 4–5 weeks of culture. The shoot forming capacity of the seeds was influenced by the BAP concentration tested (5–50 μM) and optimal response was observed at different concentrations (12.5–50 μM) in different genotypes investigated. Significant differences were recorded in terms of percent response (27.78–100%) as well as average number of shoots per explant (3.49–57.67) among the four genotypes investigated. Elongation of the induced shoots was achieved on MS basal medium containing 0.2% activated charcoal. The induction medium had a profound effect on rate of bud elongation with shoots induced on lower concentrations of BAP showing as much as four-fold elongation within 4 weeks. Proliferating shoot cultures were established by repeatedly subculturing the shoot nodes on MS medium supplemented with 5 μM BAP. Maximum rooting (91.66%) occurred in shoots cultured on half-strength MS medium supplemented with 10 μM IBA. The plantlets were successfully transferred to soil after hardening; the time period from initiation of shoot buds to transplantation being 15–17 weeks. For in vitro conservation, the shoot cultures were maintained on medium supplemented with 0.5 μM BAP and the subculture duration could be enhanced up to maximum of 11 months.     

Effect of sucrose concentrations on somatic embryogenesis in carnation (Dianthus caryophyllus L.)

The effect of sucrose concentration on callus induction followed by differentiation of embryogenic callus derived from petal explants of four carnation cultivars (Nelson, Sagres, Spirit and Impulse) was investigated. Embryogenic calli were produced on Murashige and Skoog [Murashige, T., Skoog, F.A., 1962. Revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant 154, 73–479] basal medium (MS) culture medium containing six concentrations of sucrose (3, 6, 9, 12, 15 and 18%, w/v) all supplemented with 9 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.8 μM 6-benzyladenine (BA). Maximum frequency of embryogenic callus was obtained from the media containing 9 and 12% sucrose. Somatic embryos were induced on a hormone-free MS media containing the seven concentrations of sucrose. Development of somatic embryos was enhanced by increasing sucrose concentration from 1.5 to 12%, while it was reduced in higher concentrations of 15 and 18%. However, normal embryos were not developed in the media containing 1.5 and 3% sucrose. Ninety-five percent of somatic embryos were regenerated to form the entire plantlets when they transferred onto the half-strength hormone-free MS culture medium containing 3% sucrose. Plantlets were also continued to grow normally under greenhouse condition.     

Somatic embryogenesis and Agrobacterium-mediated transformation of Japanese apricot (Prunus mume) using immature cotyledons

This study describes a successful method of somatic embryogenesis and genetic transformation using immature cotyledons of Prunus mume. Immature cotyledons from four different developmental stages of eight different P. mume cultivars were used for the experiments to optimize somatic embryogenesis and genetic transformation protocols. Somatic embryogenesis was induced when the explants were cultured on somatic embryo inducing medium consisting of MS basic medium supplemented with 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 μM 6-benzyladenine (BA). They were cultured for 30 days and then transferred to somatic embryo propagation medium containing 0.1 μM α-naphthaleneacetic acid (NAA) and 5 μM BA. It appeared that the developmental stage of the immature cotyledons used as explants was the most important factor for somatic embryogenesis; higher frequencies of somatic embryogenesis were observed when the immature cotyledons were less than 5 mm in length regardless of cultivars. For genetic transformation, the immature cotyledons were inoculated with Agrobacterium tumefaciens EHA101 harbouring a binary plasmid vector with neomycin phosphotransferase II and an intron-interrupted β-glucuronidase gene under the control of cauliflower mosaic virus 35S promoter, and three transgenic plant lines were obtained from inoculated “Sirakaga” immature cotyledons. Transgenic somatic embryos and shoots were selected using 25 mg l⁻¹ kanamycin. Integration of transgenes in the genome of GUS-positive putative transgenic shoots was confirmed by PCR and Southern blot analyses.     

Auxins increase the occurrence of leaf-colour variants in Caladium regenerated from leaf explants

Leaf explants of Caladium ‘Pink Cloud’ were cultured in vitro on MS medium containing various auxins (NAA, IBA, IAA, 2,4,5-T and 2,4-D) in combination with cytokinin (BA). NAA gave the most vigorous in vitro propagation of this plant, and only 15% of the plants were leaf-colour variants on the medium containing 0.5 μmol NAA. Leaf colour variation was observed in all plants regenerated on the medium containing 2,4-D at 0.5–4.5 μmol. In hormone-free medium, only a few leaf-colour variants (6%) occurred, but the rate of plant regeneration was very low. Application of 0.5 μmol NAA together with 4.5 μmol BA seemed to be the most appropriate for in vitro propagation of Caladium ‘Pink Cloud’ with only a few leaf-colour variants.     

Direct regeneration of plants derived from in vitro cultured shoot tips and leaves of three Lysimachia species

The regenerability of three ornamental species—Lysimachia christinae, Lysimachia rubinervis and Lysimachia nummularia ‘Aurea’, were investigated using in vitro leaves and shoot tips. 6-Benzylaminopurine (BAP) and α-naphthalene acetic acid (NAA) added to Murashige and Skoog (MS) medium were tested for their effect on organogenesis. On the medium, shoot regeneration occurred directly without callus formation. In these species, L. christinae developed the highest regeneration rate and numbers of shoots/explant from shoot tips (100%, 12.25) and leaf bases (100%, 13.01) on the MS medium containing 3.0 mg l⁻¹ BAP and 0.1 mg l⁻¹ NAA. For L. rubinervis, the highest shoot induction rate and number of shoots/explant were obtained from shoot tip (100%, 16.87–17.20) on the MS medium with 0.1 mg l⁻¹ NAA and 3.0–5.0 mg l⁻¹ BAP. L. nummularia ‘Aurea’, however, showed the highest regeneration rate and number of shoots/explant (100%, 12.73) from leaf bases on MS medium supplemented with 1.0 mg l⁻¹ BAP and 0.1 mg l⁻¹ NAA. All in vitro shoots rooted well on half macronutrient MS medium containing 0.1 mg l⁻¹ NAA. After acclimatization, transplanted plantlets grew normally and flowered in the field.     

Effect of explants source on shoot proliferation and adventitious regeneration in 10 Buddleia cultivars

Viable shoot cultures and weaned plants were obtained from cultured apical meristems with 10 Buddleia cultivars giving viabilities of 32–72%. The number of shoots produced, the micropropagation rate and the root number produced in vitro was higher in meristem derived shoots compared to those derived from shoot-tips. The subsequent growth rate of meristem derived plants, in the greenhouse, was also greater. The number of roots produced by conventional cuttings collected from meristem derived plants was significantly higher than in cuttings which were collected from plants derived from shoot-tips or from the original stock plants.Endogenous bacteria were not detected in either shoot cultures derived from meristems or in 10-week-old weaned plants derived from meristems whereas those derived from shoot-tips showed the presence of endogenous bacteria when sterilized explants were cultured on nutrient agar or on tryptic soy broth.Factors affecting adventitious bud and shoot production in leaf and internode explants was determined for ‘Lochinch’, ‘Border Beauty’, ‘Ile de France’ and ‘Pink Delight’ using meristem derived shoot cultures. Adventitious shoots appeared after 4 weeks of culture, in both types of explant when cultured on MS supplemented with 0.5–5.0 μM TDZ. The highest percentage regeneration was achieved from bisected internode explants cultured on 0.5 μM TDZ, with 93–100% regeneration among the cultivars whereas BA was less effective. The best response was obtained using 5.0 μM TDZ which gave over 10–11 shoots per explant in all bisected explants for all cultivars.     

De novo differentiation of shoot buds from leaf-callus of Dianthus caryophyllus L. and control of hyperhydricity

A method is described for producing de novo shoots from leaf derived callus of carnation (Dianthus caryophyllus L.). Plants were regenerated in four steps, viz. callus induction, shoot regeneration, removal of hyperhydricity from regenerated shoots and root development. Callus induction medium contained 2,4-D and BAP. Shoot buds were formed when the callus was further subcultured on 2,4-D- and BAP-containing medium, or MS medium without any growth regulators. The shoots so formed were hyperhydric, bushy in appearance with reduced stem length and watery leaves. The normal conformation of shoots was restored by culturing the hyperhydric shoots onto medium supplemented with GA₃ and bactopeptone. The recovered shoots were rooted on MS medium added with NAA (1 mg/l) or IBA (2 mg/l). Regenerated plants with well-developed root and shoot systems were successfully transferred to field conditions after initial acclimation.