Showing papers on "Murashige and Skoog medium published in 1997"

Micropropagation ofPanax notoginseng by somatic embryogenesis and RAPD analysis of regenerated plantlets.

Abstract: Somatic embryogenesis was induced in callus tissues derived from young flower buds ofPanax notoginseng via callus within 18 weeks of culture. The mature somatic embryos were germinated on half-strength Murashige and Skoog's (MS) medium supplemented with gibberellic acid A3(GA) and 6-benzyladenine (BA). The most suitable medium for optimal root formation proved to be MS medium supplemented with 1-naphthaleneacetic acid (NAA). Total DNA was extracted from the leaves of the regenerated plantlets ofP. notoginseng. Analysis of random-amplified polymorphic DNA (RAPD) using 21 arbitrary oligonucleotide 10-mers, showed the genetic homogeneity ofP. notoginseng. The amplification products were monomorphic for all of the plantlets ofP. notoginseng regenerated by embryogenesis, suggesting that somatic embryogenesis can be used for clonal micropropagation of this plant.

High-frequency in vitro multiplication of disease-free Zingiber officinale Rosc.

Abstract: High-frequency in vitro multiplication of disease-free clones of ginger (Zingiber officinale Rosc.) was obtained by culturing small and active buds of ginger on MS medium supplemented with 2 mg/l Kin and 20 g/l sucrose. An average of 7.7 shoots per bud was obtained on this medium after 4 weeks of culture. A high multiplication rate of well-developed plantlets (7.0 shoots per bud) with a 6.8-cm shoot length and a 7.0-cm root length was also obtained on MS medium containing 2.0 mg Kin, 2.0 mg NAA and 20 g sucrose per liter. The multiplication rate did not decrease even up to 28 months of subculture on the same medium. A simple method of successfully transferring more than 95% of tissue-cultured plants into pots was also standardized. In vitro-derived plants performed well under field conditions, were morphologically identical to the mother plants and were free from ginger yellows (Fusarium oxysporum f. sp. zingiberi). Well-developed rhizomes obtained from the tissue-cultured plants did not rot during storage of up to 6 months, thus indicating that the method is also effective in checking storage rot caused by F. oxysporum f. sp. zingiberi.

Plant regeneration from peduncle segments of oil seed Brassica species: Influence of silver nitrate and silver thiosulfate

Abstract: Cultured peduncle segments of B. juncea, B. campestris, B. napus, B. nigra and B. carinata produced shoot buds on Murashige and Skoog medium supplemented with benzyladenine and 1-naphthalene acetic acid. Supplementation of the media with 30 µm silver nitrate or silver thiosulfate enhanced the frequency of shoot regeneration. The regenerated shoots could be rooted at a frequency of 95% and transferred to soil where 75% survived and set seed.

Rapid clonal propagation of three mulberries,Morus cathayana HemsL,M. lhou Koiz. andM. serrata Roxb., through in vitro culture of apical shoot buds and nodal explants from mature trees.

Abstract: High-frequency bud break and multiple shoots were induced in apical shoot buds and nodal explants ofMorus cathayana, M. lhou andM. serrata on Murashige and Skoog (MS) medium containing 0.5-1.0 mg/l 6-benzylaminopurine (BAP). Addition of gibberellic acid (0.4 mg/l) along with BAP induced faster bud break both in apical shoot buds and nodal explants and also enhanced the frequency of bud break in all three species. Shoot culture initiation was greatly influenced by explant type, explant age and explanting season. The shoots were successfully rooted on half-strength MS medium containing a combination of indole-3-acetic acid, indole-3-butyric acid and indole-3-propionic acid, each at 1.0 mg/l. The plantlets were successfully acclimated and eventually established in soil.

Somatic embryogenesis and plant regeneration in Lilium longiflorum Thunb

Abstract: Friable callus was obtained from styles and flower pedicels of Lilium longiflorum Snow Queen and the Oriental lily hybrid Star Gazer on Murashige and Skoog (MS) media containing either 2 µm dicamba or 2 µm picloram. Cell suspension cultures were established by suspending the callus of L. longiflorum Snow Queen in liquid medium containing 2 µm dicamba. Through a purification process, a fine fast-growing cell suspension was obtained. This suspension was composed of a homogenous population of small dense cells, which tended to organise into embryo like structures (ELS). In liquid culture with the auxin dicamba, the ELS underwent continuous callus formation. When transferred to solidified hormone-free MS medium, the ELS germinated, forming complete plantlets. Histological investigation showed that in the ELS both shoot and root meristems were distinctly evident. It was concluded that the ELS obtained were in fact somatic embryos.

Direct shoot regeneration from foliar explants of an epiphytic orchid,Acampe praemorsa (Roxb.) Blatter and McCann.

Abstract: An efficient and reproducible procedure is described for the large-scale propagation of an epiphytic orchid,Acampe praemorsa (Roxb.) B latter and McCann using foliar explants. Shoot buds were induced in basal parts of foliar explants on Murashige and Skoog medium supplemented with N6-benzyladenine (BA), kinetin (Kn) or thidiazuron (TDZ), the latter being most effective at 1.0 mg/1. Shoots formed to a TDZ-containing medium elongated following transfer to a substrate supplemented with 2.0 mg/l 1-naphthaleneacetic acid (NAA) and 0.5 mg/1 BA. NAA at lower concentrations had no beneficial effects on shoot regeneration, whether added to the medium along with BA, Kn or TDZ. However, it promoted shoot elongation and leaf expansion. Higher concentrations of NAA suppressed shoot regeneration. The frequency of shoot regeneration was greatly influenced by the developmental stage and orientation of the leaf. Shoots regenerated from the foliar explants were rooted successfully on MS medium containing 1.0 mg/l indole-3-butyric acid. The plantlets were acclimated and eventually transferred to a garden.

Micropropagation of Curry Leaf Tree [Murraya koenigii (L.) Spreng.] by axillary proliferation using intact seedlings.

Abstract: An efficient and reproducible procedure for the large scale propagation of Murraya koenigii (L.) Spreng. (Curry Leaf Tree) is described. High-frequency direct shoot proliferation was induced in intact seedlings of M. koenigii on modified Murashige and Skoog (1962) (MS) medium supplemented with 5.0 mg/l benzyladenine. Shoot buds originated from the region adjacent to the apex of the primary shoot and the epicotyledonary node of the intact seedling. Shoots elongated following transfer to MS medium without plant growth regulators. The shoot-forming capacity of intact seedlings was influenced by explant orientation. Maximum shoot proliferation was obtained when the shoot-forming region was in direct contact with the medium surface or slightly embedded into the medium. Proliferating shoot cultures were established by repeatedly subculturing mother seedlings on fresh medium of the same composition after excising all newly formed shoots. Roots were formed on excised shoots when they were transfered to half-strength MS containing 1.0 mg/l indole-3-butyric acid. Plantlets were acclimatized and established in soil where they exhibited normal growth.

Direct shoot regeneration from excised leaf explants of in vitro grown seedlings of Alstroemeria L.

Abstract: A two-step protocol for the induction of shoots from Alstroemeria leaf explants has been developed. Leaf explants with stem node tissue attached were incubated on shoot induction medium for 10 days, and then transferred to regeneration medium. Shoots from the area adjacent to the region between the leaf base and node tissue regenerated within 3 weeks after transfer to the regeneration medium, without a callus phase. The best induction was obtained with Murashige and Skoog medium containing 10 µm thidiazuron and 0.5 µm indole butyric acid. The regeneration medium contained 2.2 µm 6-benzylaminopurine. After several subcultures of the leaf explants with induced shoots, normal plantlets with rhizome were formed. In Alstroemeria, the percentage of responding leaf explants is more important than the number of shoots regenerated per leaf explant, because rhizome formation is the most important factor for micropropagation. The effect of other compounds in the induction medium, including glucose, sucrose, silver nitrate, and ancymidol, on regeneration was also investigated.

Plant regeneration from callus cultures of Psoralea corylifolia Linn

Abstract: Plantlet regeneration via organogenesis was achieved in callus cultures derived form mature leaves, stems and leaves, petioles and roots of young seedling of Psoralea corylifolia on Murashige and Skoog medium supplemented with 2.5–3.0 mg L-1 BA, 1.0 mg L-1 NAA and 3% (w/v) sucrose. The rate of shoot bud regeneration was positively correlated with the concentration of hormones in the nutrient media. Shoot buds regenerated more readily from juvenile explants (seedling source) as compared to the mature explants. Addition of adenine sulphate (5 mg L-1) to the culture medium increased the growth of shoot buds. Optimum responses were obtained in hypocotyl and leaf explants using NAA in combination with BA, the highest rate of shoot bud regeneration being in hypocotyl explants. Rooting was readily achieved on the differentiated shoots on MS basal media without growth regulators. Regenerated plantlets were successfully established in the greenhouse.

In vitro multiplication of Vanilla planifolia using axillary bud explants

Abstract: A clonal propagation method has been developed for efficient multiplication ofVanilla planifolia. Multiple shoots were developed from axillary bud explants using semi-solid Murashige and Skoog (MS) medium supplemented with N6-benzyladenine (BA, 2 mg l-1) and α-naphthaleneacetic acid (NAA, 1 mg l-1). The multiple shoots were transferred to agitated liquid MS medium with BA at 1 mg l-1 and NAA at 0.5 mg l-1 for 2-3 weeks, and subsequently cultured on semi-solid medium. Using this method, an average of 42 shoots were obtained from a single axillary bud explant over a period of 134 days. Use of an intervening liquid medium has been found to enhance multiplication of shoots inV. planifolia.

High frequency plant regeneration from Eucalyptus globulus Labill. hypocotyls: Ontogenesis and ploidy level of the regenerants

Abstract: Up to 70% regenerating hypocotyls provided with 5 to 20 buds were obtained on MS medium containing 0.01 or 1 mg l-1 NAA and 0.2 mg l-1 BA or 0.2 mg l-1 BA and 0.2 mg l-1 TDZ. The ability to regenerate buds was correlated with the presence of oil glands at a stage in germination when oil secretion was not yet occurring. The regeneration of shoot meristems took place from the cells involved in the differentiation of these glands. Such glands could also appear during callus redifferentiation, giving rise to indirect regeneration. Rooting of the regenerants was efficient using a two-step procedure of induction under darkness in the presence of 3 mg l-1 IBA, followed by root development on medium devoid of growth regulators under a 16-h photoperiod, the medium being solidified with Gelrite. Regenerated plants showed no phenotypic alterations. Nuclear DNA contents in mother-plant material and regenerants were analysed using flow cytometry. There was no evidence of polyploidy in any of the samples, indicating the absence of polyploidisation during cell differentiation and under in vitro conditions. No regeneration was obtained from leaf or stem explants from micropropagated plantlets.

Genetic transformation of gentian using wild-type Agrobacterium rhizogenes

Abstract: Agrobacterium rhizogenes A4 harboring the agropine type root-inducing plasmid (pRiA4) induced hairy roots on stem sections of gentian plants. Transgenic gential plants were regenerated from the hairy roots at a frequency of 19% adventitious shoot regeneration on Murashige and Skoog medium containing 30 g l-1 sucrose, 10 mg l-1 N-phenyl-N′-1,2,3-thiadiazol-5-yl urea, 1 mg l-1 1-naphthaleneacetic acid and 2 g l-1 gellan gum. The shoots were grown to maturity in a growth chamber after acclimatization. The mature transformed plants showed distinct variations in their phenotypes, such as dwarfness. Polymerase chain reaction and Southern blot analysis revealed stable integration of transferred DNA.

Lawsone accumulation in normal and transformed cultures of henna, Lawsonia inermis

Abstract: The improvement of axillary shoot formation of Lawsonia inermis L. cultured in vitro depended on the iron concentration in the culture medium. Regenerated shoots were rooted on a hormone-free half-strength Murashige and Skoog medium (1/2 MS) before transfer to greenhouse conditions. Determination of lawsone in the plant material was investigated using a new HPLC method. The results showed that lawsone accumulation in vivo is restricted to the aerial part of the plant. In addition, the possibility of inducing lawsone biosynthesis in root cultures was studied. Hairy root cultures were established by a co-culture method using leaf segments of L. inermis and Agrobacterium rhizogenes NCIB 8196. Of several basal media tested, the production of lawsone (0.13% dry weight) was only observed in hairy roots tissues incubated in the dark and cultured in 1/2 MS or MS media.

Inhibitory effect of GA3 on the development of thidiazuron-induced somatic embryogenesis in geranium (Pelargonium xhortorum Bailey) hypocotyl cultures.

Abstract: Somatic embryogenesis in geranium (Pelargonium xhortorum Bailey cv ‘Scarlet Orbit Improved’) can be achieved by incubating hypocotyl explants on MS medium supplemented with thidiazuron (TDZ; 10 μM for 3 days followed by subculture on medium devoid of any plant growth regulators. The presence of gibberellins (GAs) during both the induction and expression phases of embryogenesis was significantly detrimental to somatic embryo formation on the hypocotyl explants. The addition of the GA-synthesis inhibitors paclobutrazol, uniconazole or ancymidol during the period of growth and differentiation of somatic embryos increased the number of somatic embryos formed on each explant. However, paclobutrazol added during the period of induction had no significant influence on somatic embryo formation. Results suggest that both exogenously supplied as well as endogenous GAs play a role, albeit a negative one, on somatic embryogenesis of geranium.

High frequency shoot regeneration and plantlet formation from root tip of garlic

Abstract: An efficient and novel method of direct shoot regeneration from root tips in garlic was developed. The influence of growth regulators, basal media and age of root explant on shoot initiation and proliferation was examined. The best growth regulator combination was 1-naphthaleneacetic acid and 6-benzyladenine at 1 and 10 µM, respectively, inducing shoot initiation from 75% of the explants. The frequency of shoot initiation on different basal media was similar. Explant root tips from plantlets taken 15 to 18 days after sprouting showed the highest shoot initiation (95%). In contrast to Murashige and Skoog medium, which produced more than 10 shoots per explant, B5 medium produced smaller shoots, although the number was higher. Rooting of individual shoots was induced after transfer to medium without growth regulators. Plantlets, after acclimatization in a growth cabinet, were successfully transplanted to the field, and no phenotypic variation was observed among them. The technique has potential applicability for rapid propagation of garlic.

Micropropagation of mature Chinese tallow tree (Sapium sebiferum Roxb.).

Abstract: An in vitro propagation technique based on axillary bud proliferation has been developed for mature Sapium sebiferum trees. Nodal segments cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (1-10μM) and α-naphthaleneacetic acid (0-0.5μM) showed axillary bud proliferation. Shoots pro- liferated in vitro were multiplied on Murashige and Skoog medium containing 2.5 μM benzyl adenine and 0.25 μM α-naphthaleneacetic acid. Seasonal changes affected the shoot proliferation potential of the initial explant. Shoots were rooted on a half-strength, growth-regulator-free, agar-gelled, MS medium after a 48-h treatment on half- strength MS liquid medium with 10 μM indole-3-butyric acid. Rooted plantlets were potted and acclimatized in a growth chamber and then moved to the greenhouse. Four- month-old plants were transplanted to the field.

Effect of sucrose on growth and galanthamine production in shoot-clump cultures of Narcissus confusus in liquid-shake medium

Abstract: In order to produce galanthamine, an alkaloid currently being tested in Alzheimer's disease therapy, we have used in vitro organ cultures of Narcissus confusus (Amaryllidaceae) plants starting from two different explants: double scale segments with basal plate from bulbs (organogenic cultures), and mature seeds (callogenic-organogenic cultures). Shoot-clumps were induced from buds obtained from twin-scales and from organogenic calluses on a MS medium supplemented with 1 mg l−1 2,4-D and 5 mg l−1 BA. Shoot-clumps were then developed partially submerged in a liquid medium. After one month of precondition, the shoot-clumps were cultured in liquid media with different concentrations of sucrose, from 3% to 18% (w/v) for 14 days. The growth of the regenerated plants treated with 9% sucrose was significantly greater. Under a photoperiod 16 h light/8 h dark, the shoot-clump cultures subjected to the two highest sucrose concentrations gave rise to higher dry weight/fresh weight ratios. Different doses of sucrose affected not only the alkaloid profile in the shoot-clump tissues but also that excreted to the medium. In all cases, shoot cultures of N. confusus were capable of galanthamine biosynthesis, with the best results at 9% sucrose concentration.

An alternative propagation method ofAnanas through nodule culture.

Abstract: A micropropagation scheme forAnanas comosus Merr. was developed using nodule culture. Nodules were induced from leaf-base or chopped shoot-base explants on modified half-strength MS medium supplemented with 2.69-5.37 μM NAA and 4.44 μM BA and could be maintained long-term as nodules. The nodules proliferated into more nodules when chopped into pieces of 1–3 mm and placed onto the same medium. They regenerated shoots when transferred to medium supplemented with 0.54–10.74 μM NAA and 0.44–8.88 μM BA. The regeneration capacity of nodules is higher than that of direct regeneration or callus. Maximum regeneration was obtained from culture medium containing 0.54 μM NAA and 0.44 μM BA, where shoots could be observed as early as within 2 weeks. Many shoots formed roots in the same medium in which they were regenerated after 10 subcultures, but the best rooting occurred in medium containing 0.54 μM NAA and 0.44 μM BA. Rooted plantlets ofA. comosus Merr. could be routinely produced at 6-week intervals.

Regeneration of haploid plants from anther cultures of the Asiatic hybrid lily ‘Connecticut King’

Abstract: A system for producing haploid plants from anther cultures was developed for the Asiatic hybrid lily ‘Connecticut King’. Anthers containing microspores at the mid- to late-uninucleate stages were cultured on MS media supplemented with various plant growth regulators. Microspores containing 3 or 4 vegetative-like nuclei were observed 2 to 3 weeks later, and yellowish nodular calluses appeared within dehisced anthers 2 to 3 months after culture. Picloram was superior to 2,4-d for inducing nodular calluses. Anthers from greenhouse-grown plants required higher concentrations of both picloram and cytokinins than those from field-grown plants and most frequently produced nodular calluses (17.6%) on MS medium containing 2 mg 1−1 picloram and 2 mg 1−1 zeatin. The nodular calluses regenerated many bulblets following transfer to MS medium supplemented with 0.1 or 0.5 mg 1−1 picloram and 0.01 mg 1−1 BA, and the bulblets developed into plantlets (bulblets with scaly leaves and roots) after transfer to MS medium containing 0.1 mg 1−1 NAA. Chromosome counts of root-tip cells of 11 plantlets revealed that five were haploids (2n = 12), two diploids (2n = 24), and four mixoploid. This result suggests that at least some plantlets were of gametophytic origin.

In vitro plant regeneration of Aristolochia indica through axillary shoot multiplication and organogenesis

Abstract: Protocols for in vitro plant regeneration via axillary and adventitious shoot regeneration were established in an important medicinal plant, Aristolochia indica L. (Aristolochiaceae). Basal Murashige and Skoog's (MS) medium supplemented with 0.54 µM α-naphthaleneacetic acid (NAA) and 13.31 µM benzyladenine (BA) induced the maximum number of shoots (45-50) from shoot tip and nodal segment cultures. Phenolic accumulation in leaf and internodal stem derived callus cultured in MS medium containing NAA or 2,4-dichlorophenoxyacetic acid and BA or kinetin was controlled by the addition of 1.0 mg l-1 phloroglucinol (PG) to the callus induction medium. Basal medium supplemented with 2.69 µM NAA, 13.31 µM BA and 1.0 mg l-1 PG induced the best results in terms of shoot bud regeneration from leaf derived callus. Direct de novo development of shoots from leaf segments was achieved using 13.31 µM BA along with 50 mg l-1 activated charcoal. The microshoots were rooted in White's medium supplemented with 2.46 µM indolebutyric acid. More than 85% of rooted plants survived in the soil.

Effects of medium components and light on callus induction, growth, and frond regeneration in lemna gibba (duckweed)

Abstract: Basal media, plant growth regulator type and concentration, sucrose, and light were examined for their effects on duckweed (Lemna gibba) frond proliferation, callus induction and growth, and frond regeneration. Murashige and Skoog medium proved best for callus induction and growth, while Schenk and Hildebrandt medium proved best for frond proliferation. The ability of auxin to induce callus was associated with the relative strength of the four auxins tested, with 20 or 50 µM 2,4-dichlorophenoxyacetic acid giving the highest frequency (10%) of fronds producing callus. Auxin combinations did not improve callus induction frequency. Auxin in combination with other plant growth regulators was needed for long-term callus growth; the two superior plant growth regulator combinations were 10 µM naphthaleneacetic acid, 10 µM gibberellic acid, and 2 µM benzyladenine with either 1 or 20 µM 2,4-dichlorophenoxyacetic acid. Three percent sucrose was best for callus induction and growth. Callus induction and growth required light. Callus that proliferated from each frond’s meristematic zone contained a mixture of dedifferentiated and somewhat organized cell masses. Continual callus selection was required to produce mostly dedifferentiated, slow-growing callus cell lines. Frond regeneration occurred on Schenk and Hildebrandt medium without plant growth regulators but was promoted by 1 µM benzyladenine. Callus maintained its ability to regenerate fronds for at least 10 mo. Regenerated fronds showed a slower growth rate than normal fronds and a low percentage of abnormal morphologies that reverted to normal after one or two subcultures.

Agrobacterium-mediated transformation of Amaranthus hypochondriacus: light- and tissue-specific expression of a pea chlorophyll a/b-binding protein promoter

Abstract: Mature embryos of Amaranthus hypochondriacus (amaranth) were used to develop an in vitro culture system for plant regeneration and genetic transformation. Plants were regenerated from embryo-derived callus cultivated on Murashige and Skoog medium supplemented with 10 µM 2,4-dichlorophenoxyacetic acid or 3,6-dichloro-2-methoxybenzoic acid and 10% coconut liquid endosperm. Transgenic plants were obtained by inoculation of mature embryo explants with a disarmed Agrobacterium strain containing the plasmid pGV2260(pEsc4), which carried the genes encoding neomycin phosphotransferase type II and β-glucuronidase. The presence of transgenes in the genome of transformed amaranth plants and their progeny was demonstrated by Southern blot hybridization. Tissue specific and light-inducible expression directed by a pea chlorophyll a/b-binding protein promoter was observed in transgenic amaranth plants and their progeny.

Plant regeneration from suspension culture of Iris germanica 1

Abstract: In Iris germanica L., 'G1', 'Adorn' and 'Rococo', induction and proliferation of embryogenic calli were achieved by culture of leaf-base explants on Murashige and Skoog (MS) medium supplemented with 1 mg l−1 2,4-D, 1 mg l−1 kinetin, 200 mg l−1 casein hydrolysate, 250 mg l−1 proline, 30 g l−1 sucrose and 2.5 g l−1 gellan gum. Among these cultivars, however, only in 'G1' could a suspension culture be established using a liquid N6 medium with 1 mg l−1 2,4-D, 1 mg l−1 kinetin, 200 mg l−1 casein hydrolysate, 250 mg l−1 proline and 30 g l−1 sucrose. Murashige and Skoog medium with 1 mg l−1 gibberellic acid (GA3), 30 g l−1 sucrose and 2.5 g l−1 gellan gum was suitable for somatic embryo formation from suspension cells. When the somatic embryos were transferred to solid, growth regulator-free MS medium and subcultured monthly, 36 shoots were obtained from 20 mg suspension cells.

Micropropagation of Spathoglottis plicata.

Abstract: A rapid and reliable micropropagation method was established for Spathoglottis plicata. Nodal and leaf explants dissected from 8-month-old pot-grown seedlings were cultured on charcoal-amended Murashige and Skoog medium supplemented with 16 combinations of α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BA) at concentrations of 0.54–10.74 µm. Regeneration of protocorm-like bodies (PLBs) and subsequent plantlet development were observed from 98.5% of the nodal explants. Only 6.5% of leaf explants and occasionally some root segments (dissected from regenerated plantlets) were able to produce PLBs and then plantlets. The optimum plant growth regulator (PGR) combination for maximal PLB regeneration was 5.37 µm NAA and 0.44 µm BA. The best combination of PGR for plantlet development was 2.69–10.74 µm NAA and 8.88 µm BA. The NAA to BA ratios for maximal PLB induction and plantlet development were 12.2 and 0.3–1.2, respectively. Regenerated PLBs and plantlets, when cut into pieces of less than 1 mm and subcultured onto the above media, regenerated new PLBs and plantlets in another 3 months.

Embryogenic callus formation and histological studies from Stevia rebaudiana (Bert.) Bertoni floret explants

Abstract: Somatic embryogenesis was obtained from floret explants of Stevia rebaudiana cultured on MS medium supplemented with 2,4-D (9.05 and 18.10 μM) and kinetin (0 to 9.29 μM). On 9.05μM 2,4-D supplemented medium maximum embryogenic callus formation occurred in medium without kinetin. On 18.10 μM 2,4-D supplemented medium the best treatment was 2.32 μM kinetin. Embryogenic callus started at the base of the corolla and ovary. Histological sections showed a fibrillar network on the surface of somatic proembryos. An unicellular origin of the somatic embryos is proposed. Additional

In vitro somatic embryogenesis ofDalbergia sissoo Roxb. -a multipurpose timber-yielding tree.

Abstract: Somatic embryogenesis was achieved in callus cultures dervied from 40-day-old semimature zygotic embryos ofDalbergia sissoo on semi-solid Murashige and Skoog (MS) salts and vitamins supplemented with 0.46–1.16 μM kinetin, 6.78–9.04 μM 2,4-dichlorophenoxy acetic acid (2,4-D) and 30 g/1 sucrose. Somatic embryos proliferated rapidly by secondary somatic embryogenesis after transfer to half-strength basal MS medium supplemented with 0.46-1.16 μM kinetin and 6.78–9.04 μM 2,4-D with 2% (w/v) sucrose. The light-green somatic embryos germinated on half-strength MS salts and vitamins supplemented with 0.5 mg/1 abscisic acid and 2% (w/v) sucrose. The developmental stages of somatic embryogenesis were studied by light and scanning electron microscopy.

Micropropagation and acclimatization of Hedeoma multiflorum

Abstract: A method for the micropropagation of Hedeoma multiflorum Benth from shoot tips or nodal segments was developed. Proliferating microshoot cultures were obtained by placing shoot tips or nodal segments on half-strength Murashige and Skoog (1962) medium supplemented with 22.2 μM BA or 22.2 μM BA plus 0.05 μM NAA. Individual shoots were excised and transferred into rooting medium containing auxins (IBA, NAA or IAA). Rooting of shoots was better on half-strength MS medium containing 0.6 μM IAA than on half-strength MS medium without growth regulators. Rooted plantlets were successfully acclimatized to soil. Preconditioning at different sucrose concentrations prior to acclimatization had no effect on plant establishment, but influenced plant quality.