In vitro propagation of mature Liquidambar styraciflua

Mature specimens of liquidambar styraciflua were propagated in vitro. Components of the nutrient medium and culture conditions were first determined for one-year-old seedling material. Mature material responded similarly to seedling material in culture, but alterations in frequency of early transfers and components of the medium were required. Explants responded best to Woody Plant Medium of Lloyd and McCown supplemented with 0.2 mg l^-1 BA and 0.05 mg l^-1 NAA. Root formation occurred on shoots placed on media containing 0.5–1.0 mg l^-1 IBA. Growth in culture and percentage of rooting of mature explants were markedly affected by the individual selection, with rooting percentages varying from 33–100% among selections.     

In vitro propagation of pummelo (Citrus grandis L. osbeck)

Summary Several experiments were carried out to develop protocols for the in vitro propagation of pummelo (Citrus grandis L. Osbeck) using shoot-tip explants from seedlings. Murashige and Skoog (MS) medium supplemented with various concentrations of 6-benzylaminopurine (BA) and thidiazuron (TDZ), singly or in combination with α-naphthaleneacetic acid (NAA), was used to determine the rate of shoot proliferation. The response of explants to all concentrations of TDZ was very poor. After 6 wk culture, the most adventitious shoots per explant (average 5.2) were obtained on medium supplemented with 1.8 μM BA. NAA with cytokinin in the medium did not improve the rate of shoot multiplication significantly. Addition of 5.8 μM gibberellic acid in shoot-proliferation medium during the second subculture improved shoot elongation significantly. Shoot multiplication increased 3.5-fold in each successive subculture. NAA was superior to indolebutyric acid for in vitro root induction. Over 75% of the shoots developed roots when transferred to half-strength MS medium with 1.3, 2.7, or 5.4 μM NAA.     

In vitro propagation of the leguminous tree Swartzia madagascariensis

Shoot induction frequency for the leguminous tree Swartzia madagascariensis Desv. was higher on MS and WP media than on B5. Explants incubated on media solidified with agar produced more shoots with a lower tendency to hyperhydricity than explants on agarose or Gelrite media. Maximum shoot induction was obtained with an agar-solidified MS medium containing 2.2 M benzyladenine (37 shoots/explant). Shoots rooted after transfer to half-strength MS medium supplemented with 26.8 M naphthaleneacetic acid.Abbreviations BA benzyladenine - IBA indolebutyric acid - NAA naphthaleneacetic acid - WP(M) woody plant (medium)     

In vitro propagation of Halesia carolina L. and the influence of explantation timing on initial shoot proliferation

Halesia carolina L., a small, ornamentally valuable tree, is difficult to propagate due to the complexity of seed propagation and the unavailability of propagules for conventional vegetative propagation. A micropropagation system was developed to facilitate easy propagation of this species. Actively growing shoot tips achieved optimum shoot proliferation from axillary buds when placed on Woody Plant Medium supplemented with 1.0 to 2.5 mg/l benzyladenine. The addition of 0.1 mg/l naphthaleneacetic acid had little effect on culture performance. Murashige and Skoog medium was incapable of supporting vigorous shoot proliferation. Non-sterile rooting conditions provided better rooting and subsequent plantlet growth, when compared to an in vitro rooting method. The seasonal fluctuations in the stock plant dramatically affected the shoot proliferating potential of the explants in vitro. Rapidly elongating shoots formed shoot proliferating cultures more slowly than explants taken either before or after the rapid elongation phase.     

Propagation of Ficus carica L. clones by in vitro culture

This experiment is designed to determine the most suitable conditions and media for propagating three selected fig (Ficus carica L.) clones through tissue culture. The clone 37 displayed a higher performance than clones 50 and 82. As the multiplication medium, the Murashige and Skoog (MS) medium containing 1 mg dm⁻³ α-indole-3-butyric acid (IBA), 1 mg dm⁻³ gibberellic acid and 5 mg dm⁻³ 6-benzyladenine were the best, whereas, MS medium complemented with 1.2 and 2.5 μM IBA or 1-naphthalene acetic acid (NAA) were better in respect to rooting. Peat followed by volcanic tuff gave the best performance for acclimatization to outdoor conditions.     

In vitro propagation ofCereus peruvianus mill. (cactaceae)

Summary Cereus peruvianus seedlings were used as a source of stem explants to determine the effective conditions for inducing and maintaining callus tissues in a state of rapid growth, as well as to obtain plants regenerated from callus cultures. Factorial combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin in MS medium were tested, and we concluded that the 18.1µM 2,4-D and 18.6 or 27.9µM kinetin combinations were suitable for callus induction. The cactus shoots were produced from the friable callus; root elongation occurred within 2 wk in medium without 2,4-D and with 18.6µM kinetin. This method can be used to rapidly produce manyC. peruvianus plants.     

番木瓜的离体繁殖

建立番木瓜离体繁殖体系.用0.1%HgCl2溶液对番木瓜的新生嫩茎进行消毒,适宜的消毒时间为12min,1mm茎尖的成苗率达到87.6%.随蔗糖浓度的提高,番木瓜试管苗的株高显著降低,增殖系数显著增加.在附加IBA0.3mg/L的1/2MS培养基上新梢的生根率达到89.3%,试管苗大规模移栽的成活率达90%以上.基因型显著地影响番木瓜离体增殖的效率.     

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.     

The control of shoot tip necrosis in Pistacia vera L. in vitro

The effect of increased concentrations of calcium (Ca) (3–24 mM) and boron (B) (100–800 M) in the medium was studied on the occurrence of shoot tip necrosis (STN) in cultures of Pistacia vera L. STN was significantly reduced by application of Ca or B, however media with more than 200 M boron had reduced shoot multiplication. Ca (12–24 mM) supplied as calcium chloride reduced STN without any adverse effect on shoot multiplication or elongation, whereas calcium acetate reduced elongation. It is concluded that STN is a physiological mineral disorder associated with Ca and/or B deficiency in the meristematic regions of actively growing shoots. Application of Ca (up to 24 mM) as calcium chloride to the medium was the best treatment for the control of STN. Reduction of humidity or increased aeration in the culture jars did not have any significant effect on the occurrence of STN.Abbreviations MS Murashige and Skoog medium - STN Shoot tip necrosis     

High frequency in vitro propagation of Kidney Tea Plant

Multiple shoots were obtained on MS medium containing     

In vitro propagation ofSalix tarraconensis Pau ex Font Quer,an endemic and threatened plant

Summary Salix tarraconensis Pau ex Font Quer, an endemic willow species from northeast Spain, was micropropagated with nodal segments. Shoot multiplication was obtained with different cytokinins, either on Murashige and Skoog medium or woody plant medium. Best results for shoot formation were obtained on Murashige and Skoog medium containing 4.9 μM of 6-γ-γ-dimethylallylaminopurine. Shoots showed strong apical dominance, and some cultures displayed apical necrosis. Benzyladenine gave the worst results; shoots displayed very slow growth, deformed leaves, and hyperhydrity. Good rooting of shoots was obtained with different auxins or without plant growth regulators on woody plant medium. The best results (90-100%) were obtained within 20 d. On rooting media with indole-3-butyric acid or indoleacetic acid, shoot elongation was good (35-40 mm length). Apical necrosis was observed in elongating shoots on rooting medium, but this disturbance favored axillary bud sprouting and formation of new shoots. Shoot length and quality of roots decreased gradually as the concentration of naphthaleneacetic acid increased. Plant survival was 90% 4 weeks after removal fromin vitro conditions.     

In vitro clonal propagation of Pisum sativum L.

A system of in vitro clonal propagation has been developed in Pisum sativum L. (cv. Bohatýr). A modified MS-medium supplemented with 20 M 6-benzylaminopurine (BAP) and 0.1 M -naphthaleneacetic acid (NAA) was used to induce multiple shoot formation from shoot apices, axillary buds of the first normal leaf, axillary buds of the first and second primary scales and axillary buds of cotyledons of 4 to 6 day old pea seedlings. Meristem explants maintained a high proliferation ability in each subculture in the course of 20 months of the culture. Regenerated shoots were rooted in the same basal medium containing 5 M NAA. Rooted plants were cultured in hydroponic pots filled with half-strength MS-medium to attain anthesis and seed maturity. The phenotypic uniformity of the regenerants was evaluated. Cytological investigation confirmed the diploid stage (2n=14) of regenerants and their progeny. Histological studies revealed that proliferating shoots originated from axillary and adventitious buds. In vitro propagation is discussed as related to pea breeding.     

Agar and ammonium nitrate influence hyperhydricity,tissue nitrate and total nitrogen content of serviceberry (Amelanchier arborea) shoots in vitro

Shoot tip cultures of Amelanchier arborea Michx.f. were grown on Murashige & Skoog or Woody Plant (WP) medium containing 4.4 M benzyladenine and various concentrations of agar. Increases in agar concentration affected various culture growth variables, decreased culture hyperhydricity and increased tissue nitrate concentration. Additions of ammonium nitrate to cultures grown on WP medium containing 0.4% agar increased all growth variables measured except percent dry weight. Hyperhydricity and tissue nitrate concentration also increase in response to increasing ammonium nitrate in the medium. Since hyperhydricity was shown to be both positively and negatively correlated with increases in tissue nitrate content, it is unlikely that tissue nitrate level alone directly affects hyperhydricity.Abbreviations BA benzyladenine - MS Murashige & Skoog - WP Woody Plant     

In vitro propagation of Dipterocarpus alatus and Dipterocarpus intricatus

Seedlings were grown in vitro from embryos of Dipterocarpus alatus and D. intricatus. The problem of explant browning could be overcome by growing embryos initially on a filter paper bridge in liquid medium with activated charcoal. The best basal medium was Woody Plant Medium without the ammonium nitrate. Cytokinin appeared to stimulate seedling growth, 5×10^-5 M 2-isopentenyladenine and 10^-4 M 6-benzyladenine (BA) being the optimum concentrations for D. alatus and D. intricatus respectively. Cotyledonary nodes, excised from the seedlings, were induced to form axillary shoots and in the case of D. intricatus these could be multiplied rapidly. D. intricatus shoots elongated by reducing the BA level from 10^-5 M to 5×10^-7 M. Roots developed when shoots were dipped in 10^-3 M indolebutyric acid for two minutes and subsequently grown in liquid medium supported by a filter paper bridge.Abbreviations AC activated charcoal - BA 6-benzyladenine - 2iP 2-isopentenyladenine - IBA indolebutyric acid - MS Murashige & Skoog medium - PVP polyvinylpyrrolidone - PVPP polyvinylpolypyrrolidone - WPM Woody Plant Medium - 1/2 WPM Woody Plant Medium with half-strength macro salts - WPM (-NH₄NO₃) Woody Plant Medium without ammonium nitrate     

In vitro propagation of Paphiopedilum orchids

Paphiopedilum is one of the most popular and rare orchid genera. Members of the genus are sold and exhibited as pot plants and cut flowers. Wild populations of Paphiopedilum are under the threat of extinction due to over-collection and loss of suitable habitats. A reduction in their commercial value through large-scale propagation in vitro is an option to reduce pressure from illegal collection, to attempt to meet commercial needs and to re-establish threatened species back into the wild. Although they are commercially propagated via asymbiotic seed germination, Paphiopedilum are considered to be difficult to propagate in vitro, especially by plant regeneration from tissue culture. This review aims to cover the most important aspects and to provide an up-to-date research progress on in vitro propagation of Paphiopedilum and to emphasize the importance of further improving tissue culture protocols for ex vitro-derived explants.     

In vitro propagation of the nitrogen-fixing tree-legume Acacia mangium Willd.

In vitro propagation was initiated from 2-week-old and 7-month-old explants of Acacia mangium. Juvenile explants (2 week-old) of 5- to 10-mm lengths composed of two leaves were cultured on Murashige and Skoog (MS) medium containing 1.0 or 2.0 mg L^-1 6-benzyladenine (BAP). After 6 weeks, most explants had formed a large cluster of 14–18 axillary shoots produced by prolific branching of the primary axillary shoot after elongation. The maximum multiplication rate (40) was obtained in the first subculture; the rate decreased to 10–20 in the second one. The mean length of shoots was not significantly affected by BAP concentrations during the subsequent cultures. Rooting ability of juvenile explants was greatly affected by BAP concentrations used in the multiplication medium. When both types of explants were multiplied on a MS medium containing 1.0 mg L^-1 BAP and transferred to a half-strength MS medium containing 0.05 mg L^-1 IBA, only 10% of the juvenile explants were rooted versus 70% of the 7-month-old explants. Rooted plants transferred onto artificial substrate were all nodulated, when inoculated with a specific Bradyrhizobium sp. strain.     

Natural light as an alternative light source for the in vitro culture of banana (Musa acuminata cv. ‘Grande Naine’)

The concept of using sunlight for micropropagation systems is proposed as a way of reducing tissue culture costs. Shoot tips of Musa acuminata cultivar ‘Grande Naine’ were cultured in a non-controlled natural light environment at the IAEA Laboratories, Austria during summertime. Significantly more shoots were produced by plantlets cultivated in a sunlit room with photosynthetic photon flux densities (PPFD) fluctuating up to 570 μmol m-2 s-1, temperatures between 23 and 30 °C and photoperiods of 12 to 16-h, than by plantlets under artificial light in a growth chamber providing controlled conditions of a constant PPFD of 65 μmol m-2 s-1, temperatures ranging from 23 to 29 °C and a 16-h photoperiod. Highest multiplication rates were achieved in a greenhouse with PPFD reaching 860 μmol m-2 s-1 and temperatures of 18 – 43 °C, but browning of leaves and loss of turgor occurred. Nevertheless, rooted plantlets showed 100% survival during acclimatisation and normal development. Photoperiods of 12 – 16 h did not affect the multiplication rates. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro propagation of Valeriana jatamansi

Valeriana jatamansi Jones is an important medicinal plant. This wild herb is being exploited for its roots and rhizomes which contain valepotriates, which are highly effective against leprosy. The aim of this study was to establish a practical method for rapid and large-scale multiplication of V. jatamansi by induction of shoot proliferation from shoot buds. The sterilized explants were established on solid medium supplemented with benzyl adenine alone or in combination with indole-acetic acid or naphthalene acetic acid. The buds cultured on nutrient medium supplemented with BA and IAA or NAA formed shoots, which after 3-4 weeks produced roots on the same medium. One hundred per cent survival was obtained on hardening and field establishment of well rooted shoots. This revised version was published online in June 2006 with corrections to the Cover Date.