Cultural factors influencing adventitious shoot and plantlet formation from slash pine cotyledons

Cultural factors affecting in vitro shoot and subsequent plantlet formation of slash pine (Pinus elliotti Engelm.) cotyledons were investigated. Basal media composition, N⁶-benzylaminopurine (BAP) concentration and exposure time significantly influenced bud induction in cotyledons cultured under a continuous photoperiod of 35–40 mol m^–2 s^–1 at 24 ± 1 °C. The largest number of adventitious shoots was obtained after 28 days exposure to 66 M BAP-supplemented modified Gresshoff and Doy 1 (GD1) medium. Relatively high frequencies of large shoots were obtained after a 14-day exposure to 22 M BAP-supplemented Brown and Lawrence (BL) or 66 M BAP-supplemented GD1. Adventitious shoots derived from 21- or 28-day exposures to BAP developed more slowly and were smaller in size than those derived from a 14-day exposure to the cytokinin. Shoot differentiation and subsequent growth were also influenced by basal media, media concentration, and presence of activated charcoal in the medium. The percentage of cotyledons forming shoots was highest on half-strength GD1 medium containing activated charcoal. Rooting was achieved in vitro under a continuous photoperiod of 60–70 mol M^–2 S^–1. Roots were formed when excised shoots were planted on GD 1/2 medium supplemented with 2.68 M 1^–1 a-napthaleneacetic acid (NAA) with or without BAP for 14 days. The proposed technique of slash pine propagation using cotyledon explants can produce up to 100 seedlings per embryo.     

Preservation of Juniperus thurifera L.:a rare endangered species in Algeria through in vitro regeneration

Juniperus thurifera L.is an endemic Cupres saceae from the Aure`s Mountains of north eastern Algeria and endangered,in part,due to the scarcity of viable seeds It is threatened by other abiotic factors and the lack of an effective management strategy will increase its risk o extinction.The dearth of information on its in vitro regeneration impedes its application in forest managemen programs.We therefore developed a micropropagation protocol using microcuttings with auxiliary buds.Cuttings were grown on different combinations of media supplemented with plant growth regulators at different concentrations.The highest number of shoots and branches regenerated from original shoots was obtained on Woody Plant Medium(WPM)supplemented with 6-benzylaminopurine(BAP)(0.5 mg L^-1)and 2,4-dichlorophe noxyacetic acid(2,4-D)(0.25 mg L^-1).The best elongation of shoots was achieved with WPM supplemented with0.5 mg L^-1of BAP and 0.25 or 1 mg L^-1 of 2,4-D.On the second subculture,shoots had a higher number of branches than those of the first.The highest rooting rate,38.8%,was obtained with shoots cultured in 1/2 Murashige and Skoog(MS)medium supplemented with 5.0 mg L^-1each of indol-3-butyric(IBA)and naphthalene acetic acid(NAA).Similarly,the highest root numbers and lengths were produced on 1/2 MS medium supplemented with IBA and NAA(5.0 mg L^-1each).During transfer to acclimatization,rates of plant losses of 50% occurred.The second part of the experiment showed that the best shoot callusing was on WPM supplemented with BAP and 2,4-D,with either the combination 0.5+0.25 or 0.25+0.25 mg L^-1.The results of this research provide a starting point for further studies on in vitro regeneration of J.thurifera for the sustainable management of its unique ecosystem in the Mediterranean basin.     

An Efficient Micropropagation Protocol for High-Frequency Plantlet Regeneration from Liquid Culture of Nodal Tissues in a Medicinal Plant,Turnera ulmifolia L.

A highly efficient, stable, and cost-effective micropropagation protocol for the conservation of a medicinal plant Turnera ulmifolia L. was established from nodal tissues via multiple axillary shoot proliferation on using Murashige and Skoog’s (MS) liquid nutrient medium. To begin with, nodal explants were placed on agar gelled medium amended with 2.0 mg L^?1 6-benzylaminopurine (BAP) and 0.1 mg L^?1 indole-3 acetic acid (IAA) for shoot induction. Subsequently, elongation of regenerated shoots could be possible on liquid MS medium supplemented with 0.5 mg L^?1 BAP and Kin (kinetin) each along with 0.1 mg L^?1 IAA where high frequency of regeneration in terms of number of shoots (47.2 shoots/explant) was achieved. Furthermore, long and healthy shoots (4?5 cm in length) were rooted on agar gelled half-strength of MS medium supplemented with 2.0 mg L^?1 indole-3 butyric acid (IBA). Finally, in vitro regenerated plantlets were gradually acclimatized in the greenhouse and transferred to the field successfully.     

A modified Murashige and Skoog media for efficient multipleshoot induction in G. arborea Roxb.

This paper reports on the effect of various micropropagation factors of Gmelina arborea Roxb. through multiple shoot induction. Factors like the source and age of explants, plant growth regulators （PGRs）, media composition, and carbon source affected multiple shoot-ing in the present study. Among all the explants used, only shoot tips derived from one, two, and three week old seedlings could form multiple shoots. Besides, the formation of multiple shoots depended on the con-centration and combination of PGRs. Among all the PGRs, BAP （6-benzylaminopurine） alone gave the highest regeneration efficiency. Simi-larly, IBA （Indole-3-butyric acid） was the most efficient PGR in inducing root formation in the microshoots. Media composition and carbon source also affected the regeneration efficiency. MS （Murashige and Skoog medium） proved to be the best media for regeneration followed by B5, SH （Schenk and Hilderbrandt medium） and WPM （Woody plant medium） in that order. Similarly, among sugars, only sucrose and glucose sup-ported induction of microshoots. Based on this study we recommend the use of glucose in place of sucrose in MS medium for maximum regenera-tion efficiency.     

Effects of Thidiazuron,basal medium and light quality on adventitious shoot regeneration from <Emphasis Type="Italic">in vitro</Emphasis> cultured stem of <Emphasis Type="Italic">Populus alba</Emphasis>×<Emphasis Type="Italic">P. berolinensis</Emphasis>

The effect of Thidiazuron （TDZ）, basal media and light quality on adventitious shoot regeneration from in vitro cultured stem of Populus albaxP berolinensis were determined to establish a high efficiency shoot regeneration system from stem explants of P. alba~P berolinensis. Stems ofPopulus alba~P berolinensis were collected from cultured shoots in vitro derived from dormancy buds of 3-year-old seedlings. The stem explants were cultured on MS medium containing 0.02-mg·L-1NAA （naphthaleneacetic acid）, and 0.1, 0.3, 0.5 and 1.0 mg·L-1 concentrations of TDZ to determine the effect of TDZ on shoot regeneration. Three basal media, i.e. MS, woody plant medium （WPM） and B5, were used to test their influences of different media on adventitious shoot regeneration. Green, red, blue and yellow plastic films in comparison with florescent light as control were used to observe their effects on shoot regeneration. The results showed that differ- ent concentrations of TDZ had an evident influence on shoot regeneration. Lower concentration of TDZ （0.1 mg·L-1） resulted in more ad- ventitious shoot regeneration and higher concentration of TDZ （〉0.1 mg·L-1） inhibited shoot regeneration. Among different media, MS medium exhibited a high efficiency for shoot regeneration, followed by WPM medium, while B5 medium inhibited shoot regeneration. Normal light and yellow light exhibited better effects on shoot regeneration, compared with other light.     

Embryo culture is an efficient way to conserve a medicinally important endangered forest tree species Strychnos potatorum

The present study reports a protocol for germination of Strychnos potatorum (ver. Tel. Chilla) using zygotic embryo culture as an embryo rescue method. A 100% germination rate was obtained by culturing the embryos on full-strength Murashige and Skoog’s medium (MS) containing 20 g/L sucrose in comparison to McCown and Lloyd’s Woody Plant Medium (WPM). Germination rates decreased when the sucrose concentration was lower or higher than 20 g·L-1 . WPM/MS medium containing glucose at levels 30, 20, 15 g·L-1 showed a smaller percentage of germination and at quarter strength, WPM/MS medium with glucose did not respond. Multiple shoot formation was found at 1.0 2.0 mg/L BAP; 3.0 mg/L Kn; 2.0 mg/L TDZ on MS medium with 20 g·L-1 sucrose. Germination rates improved when the embryos were placed upright (vertically) in the medium. The in vitro germinated seedlings were acclimatized in a walk-in-chamber and maintained in the green house with the survival rate of 65% 75%. These plants were transferred to the field and were found to be phenotypically normal, healthy and similar to donor plants. This protocol will be useful to overcome seed dormancy and for rapid multiplication and conservation of S. potatorum using zygotic embryo culture.     

Clonal propagation ofGmelina arborea Roxb. byIn vitro culture

In vitro propagation technique ofGmelina arborea multipurpose and a fast growing tree species was studied. Nodal segment including axillary bud was used as a explant. They were cultured on MS media containing various concentrations (0–10 mg/l) of BAP alone or in combination with 0.002 mg/l of IBA. Nodal segments showed axillary bud proliferation in almost all media tested. MS media containing 0.22 mg/l of BAP alone and 2 mg/l of BAP in combination with 0.002 mg/l of IBA were effective for inducing multiple shoots and shoot elongation. MS medium supplemented with 0.02 mg/l of NAA and 1 mg/l of IBA gave the best result for rooting. The regenerated plantlets were potted and acclimatized successfully in a growth chamber and then moved to the green house. Adventitious shoots production from stem explants that were taken from regenerated plantletin vitro was also discussed. Stem segments were tested for their morphogenetic potential on MS media with various combinations and concentrations of BAP, zeatin and TDZ. Successfull result was obtained on MS media supplemented with 2 mg/l of BAP and 1 mg/l of zeatin or supplemented with 0.5 mg/l of BAP and 0.5 mg/l of TDZ. The shoots obtained on MS media containing 2 mg/l of BAP and 1 mg/l of zeatin rooted on MS media containing 0.02 mg/l of NAA and 1 mg/l of IBA, and plantlets were successfully obtained. A part of this paper was presented at the 109th Annual Meeting of the Japanese Forest Society (1998).     

Micropropagation of Vegetable Rennet (Withania coagulans [Stocks] Dunal)—A Critically Endangered Medicinal Plant

Withania coagulans (Stocks) Dunal (Solanaceae), popularly called vegetable rennet, is a critically endangered and highly valued medicinal plant. Overexploitation and reproductive failure forced the plant species toward the verge of complete extinction. We describe here the development of a simple, rapid, and cost effective in vitro micropropagation system for W. coagulans for mass-scale production of true-to-type plantlets using nodal shoot segments. Exactly 95.5 ± 0.34% explants responded within 8–10 days (d) and produced multiple shoot buds (4.1 ± 0.10 shoots of 2.95 ± 0.15 cm length) on 0.8% agar-gelled Murashige and Skoog's (MS) basal medium supplemented with 8.88 μM 6-benzylaminopurine (BAP), 0.57 μM indole-3-acetic acid (IAA), and additives (100 mg L^?1 L-ascorbic acid, 25 mg L^?1 each citric acid, adenine sulphate, and L-arginine). The shoots in cultures were multiplied by repeated transfer on MS medium with 4.44 μM BAP, 0.57 μM IAA, and additives. Further cultures were multiplied on a large-scale through the subculturing of shoot clumps differentiated in vitro, on MS medium supplemented with 1.11 μM BAP, 0.57 μM IAA, and additives. Maximum number (19.1 ± 0.28) of healthy (6.15 ± 0.25 cm) and viable shoots differentiated on this medium. The microshoots were rooted both in vitro and ex vitro. Exactly 67.3 ± 1.01% microshoots rooted in vitro within 25–30 d on agar-gelled half-strength MS salts supplemented with 29.52 μM indole-3-butyric acid (IBA) and 200 mg L^?1 of activated charcoal (AC). Alternatively, 73.8 ± 0.65% cloned shoots rooted on sterile soilrite (soilless compost and soil conditioner) under ex vitro conditions after pulse treatment with 2.46 mM IBA for 300 s. The clones of W. coagulans were hardened in a greenhouse within 40–45 d by slow and gradual exposure of plantlets from high relative humidity (RH; 70–80%) and low (26 ± 2°C) temperature to low RH (40–50%) and high (34 ± 2°C) temperature. The hardened plantlets were transferred to soil and stored in agro-net house with more than 90% survival rate. Replacement of pure and laboratory grade sucrose with commercial grade sugar, use of less expensive commercial grade agar-agar in culture medium, higher rate of shoot proliferation, single step ex vitro rooting, and hardening of plantlets in the greenhouse are advantageous features of the protocol. The micropropagation protocol defined here is reproducible, easy to follow, and would be helpful in large-scale restoration programs through true-to-type mass-multiplication of W. coagulans.     

Establishment of in vitro culture of Populus euphratica Olivier

The purpose of our study was to establish a regeneration system for micropropagation of Populus euphratica Olivier. On the basis of an analysis of plant leaf mineral nutrients, a special medium was proposed, called MP2. In optimizing media for in vitro plant cultures including MS, B5 and MP2 media we employed hormones, auxin IAA, cytokine benzyladenine (BAP) and gibberellic acid (GA) in our factorial experiments on media. Adventitious shoots were derived from cuttings of adult plants taken from Xingjiang, west China, on selected media with MP2 0.5 mg·L-1 BA 0.1 mg·L-1 NAA. The shoots were elongated on a medium with 0.25 mg·L-1 BAP, 0.1 mg·L-1 NAA and 2 mg·L-1 GA and were then rooted on a medium with 0.2-0.5 mg·L-1 IBA. All the media were incorporated with 30 g·L-1 sucrose and an adjusted pH at 6.3.     

Micropropagation of Selected Genotype of Aloe vera L.—An Ancient Plant for Modern Industry

Aloe vera Linn. (Syn. Aloe barbadensis Mill; Gwar-patha in Hindi) belongs to family Liliaceae. The plant, for its medicinal properties, has commercial value. Some of the genotypes of Aloe vera are consumed as a vegetable and processed to make curry and other edible products. We report here on the development of an efficient method for rapid clonal propagation by shoot proliferation from axillary meristem(s) of selected germplasm of Aloe vera. Explants were pretreated with 0.1% aqueous solution of both streptomycin and bavistin separately, each for 15 min. These were surface sterilized with 0.1% aqueous solution of mercuric chloride (HgCl₂) for 4–5 min and washed several times with autoclaved water. These were kept in a chilled, sterile antioxidant (200.0 mg L^?1 of ascorbic acid, 50.0 mg L^?1 of citric acid, and 25.0 mg L^?1 of polyvinylpyrrolidone; PVP) solution and cultured on semi-solid Murashige and Skoog's (MS) medium. The bud explants produced multiple (10.3 ± 0.675/explant) shoots on MS medium containing 13.32 μM of 6-Benzylaminopurine (BAP) and 100.0 mg L^?1 of ascorbic acid, 50.0 mg L^?1 each of citric acid and PVP, with 25.0 mg L^?1 each of arginine and adenine sulphate as additives. The shoots were further multiplied by (a) repeated transfer to fresh MS medium with additives + 13.32 μM BAP, and (b) subculturing on MS medium with a lower (4.44 μM) concentration of BAP. On MS medium containing 4.44 μM of BAP and additives, a maximum number (27.8 ± 0.63) of shoots were produced. In liquid MS medium with 4.44 μM of BAP, the rate of shoot multiplication increased and the vigor of the shoots improved. One hundred percent of the cloned shoots rooted under in vitro conditions on hormone-free half-strength MS salts containing 200.0 mg L^?1 of activated charcoal at 32 ± 2°C. The cloned shoots treated with 2.46 mM of indole-3-butyric acid (IBA) or 2.473 mM of β-naphthoxyacetic acid (NOA) for 5 min rooted under ex vitro conditions in the greenhouse. The rooted plants were hardened in the greenhouse and stored under an agro-net house. The cloned plants were transferred under different field conditions at various sites in Western Rajasthan. These plants grew normally. The higher rate of shoot multiplication and easier approach of direct rooting and hardening make this method superior to the methods previously reported on cloning/tissue culture of Aloe species. From a single shoot bud, approximately 5000 plants can be produced within 180 days.     

In vitro regeneration of Salix nigra from adventitious shoots

Black willow (Salix nigra Marsh.) is the largest and only commercially important willow species in North America. It is a candidate for phytoremediation of polluted soils because it is fast-growing and thrives on floodplains throughout eastern USA. Our objective was to develop a protocol for the in vitro regeneration of black willow plants that could serve as target material for gene transformation. Unexpanded inflorescence explants were excised from dormant buds collected from three source trees and cultured on woody plant medium (WPM) supplemented with one of: (1) 0.1 mg l(-1) thidiazuron (TDZ); (2) 0.5 mg l(-1) 6-benzoaminopurine (BAP); or (3) 1 mg l(-1) BAP. All plant growth regulator (PGR) treatments induced direct adventitious bud formation from the genotypes. The percentage of explants producing buds ranged from 20 to 92%, depending on genotype and treatment. Although most of the TDZ-treated inflorescences produced buds, these buds failed to elongate into shoots. Buds on explants treated with BAP elongated into shoots that were easily rooted in vitro and further established in potting mix in high humidity. The PGR treatments significantly affected shoot regeneration frequency (P < 0.01). The highest shoot regeneration frequency (36%) was achieved with Genotype 3 cultured on 0.5 mg l(-1) BAP. Mean number of shoots per explant varied from one to five. The ability of black willow inflorescences to produce adventitious shoots makes them potential targets for Agrobacterium-mediated transformation with heavy-metal-resistant genes for phytoremediation.     

Regeneration of <Emphasis Type="Italic">Melia volkensii</Emphasis> Gürke (Meliaceae) through direct somatic embryogenesis

Experiments were conducted to study plant regeneration through direct somatic embryogenesis using mature zygotic embryo and cotyledonary explants from seeds of Melia volkensii stored for <3 and >12 months. Explants were cultured on Murashige and Skoog (MS) medium supplemented with BAP, NAA and 2,4-D (0.5, 1.0 and 2.0 mg l⁻¹) alone, and BAP (0.5, 1.0, 2.0 and 4.0 mg l⁻¹) in combination with 2,4-D or NAA (0.2 and 0.5 mg l⁻¹). After 4 weeks in culture, up to 60% of cotyledonary explants from the seeds stored for <3 months produced direct somatic embryos on BAP (0.5–4.0 mg l⁻¹) in combination with 2,4-D (0.2 mg l⁻¹). The number of somatic embryos ranged from 5 to 14 per explant in BAP (0.5 mg l⁻¹) and 2,4-D (0.2 mg l⁻¹) combination. Only 20% of cotyledonary explants from seeds stored for >12 months produced somatic embryos. Mature zygotic embryos failed to produce any somatic embryos. Subcultures of somatic embryos from cotyledonary explants of seeds stored for <3 months formed clusters of shootlets on semi solid MS and 1/2 MS media. After 6 weeks of subculture on multiplication MS media augmented with BAP (0.5 mg l⁻¹) and IAA (0.2 mg l⁻¹), 70% of the shoot tips formed 4–7 shoots per explant. Up to 33% of the multiplied shoots were rooted in MS medium supplemented with 2.0 mg l⁻¹ IBA. Plantlets developed normally into seedlings in the greenhouse.     

Modulation of in vitro morphogenesis in nodal segments of Salix tetrasperma Roxb. through the use of TDZ, different media types and culture regimes

A comparative performance of two different media formulations (woody plant medium (WPM) and Murashige and Skoog??s (MS) medium) for their ability to inflict in vitro shoot development in nodal segments of Salix tetrasperma Roxb. has been carried out. Thidiazuron (TDZ) in various concentrations was used as a supplement to the basal media. Media types, TDZ concentrations, exposure duration and culture regimes played an important role in affecting multiple shoot production. WPM supplemented with 2.5???M TDZ for 4?weeks exposure was found to be the best for maximum (4.53?±?0.27) shoots production in vitro. Transfer to a secondary medium consisting of 6-benzyladenine (1.0???M) and ??-naphthalene acetic acid (0.5???M) enhanced the multiplication rate and by the end of 12?weeks, 20.33?±?0.33 shoots with shoot length, 4.70?±?0.26?cm were produced on WPM. Rooting of the regenerated shoots was achieved on half strength basal media (either WPM or MS) containing 0.5???M indole-3-butyric acid. In all the experiments, different growth parameters were scored and WPM was found to be superior to MS medium. The regenerated plantlets were successfully acclimatized in the field with about 81?% survival.     

In Vitro Propagation of the Important Tasar Oak (Quercus serrata Thunb.) by Casein Hydrolysate Promoted High Frequency Shoot Proliferation

An efficient micropropagation protocol has been developed for tasar oak. Nodal segments from in vitro grown seedling were used for shoot multiplication. Best shoot multiplication response, in terms of number of shoots per explant as well as shoot length, was obtained in woody plant (WP) medium supplemented with 6-benzyladenine and indole-3-acetic acid (8.88 μM BA + 1.43 μM IAA); but the establishment of cultures was difficult due to basal callus formation and necrosis in due course of time. Out of the two used growth adjuvants, casein hydrolysate (CH, 500 mg L^?1) promoted shoot multiplication rate significantly in comparison to silver nitrate and also eliminated the basal callus formation problem and necrosis faced during the later stage of shoot proliferation. In vitro rooting on WP medium supplemented with 100 μM indole-3-butyric acid (IBA) when applied for 48 hr gave the best results in comparison to prolonged exposure. Well-acclimatized plantlets were transferred to the field with 80% survival rate. This protocol could be useful not only to propagate and conserve this oak but can also uplift the socioeconomic status of the Himalayan people as its leaves are used to feed the tasar silk worm during rearing period. This method will also be helpful for propagation of high value trees for a reforestation program.     

Multiplication of Elaeagnus angustifolia L. from a Single Shoot in Vitro

1INTRODUCTIONElaeagnusangusifoliaLisahighlytolerantnativewoodyspeciesinsouthernEuropeandAsia.Itmaybeusedinreforestationandsoil-waterconservationandforanexcellentwindbreaktoarrestwind(Bertrand,1985;LiShaozhong,etal,1997),materialsoffragranceandmedicineandnutritivefood(ChangZhaofeng,etal,1994;Goncharova,1997;Rasekh,1999;Ahmadiani2001;JiangFashou,etal,2002).Insomepreviousresearches,BA,2ip,KN(Bertrand,1985,Economou,1988)andBA(Iriondo1995;Mariella,1996)wereusedinshootmultiplicationofE…     

An efficient method for clonal propagation and in vitro establishment of softwood shoots from epicormic buds of teak (Tectona grandis L.)

Softwood shoots were produced from 40 cm long stem segments placed horizontally in flat trays containing sterilized sand under natural light or shade conditions for subsequent rooting and micropropagation studies in teak (Tectona grandis L.). Higher number of shoots (6.17) per log was produced under natural light as compared to shade conditions. Forcing was also better in natural light as compared to shade in terms of shoot length, number of nodes or leaves. For rooting, 2–4 cm long softwood shoots were excised and treated with either indole-3-butyric acid (IBA) or α-naphthyl acetic acid (NAA) at 0, 1000, 2000 or 3000 μmol·L^–1 each or with combinations (1000 + 1000, 2000 + 2000 or 3000 + 3000 μmol·L^–1) and then placed in flat trays containing autoclaved sand at 25 ± 2ºC in 16 h photoperiod at 35 µmol·m^–2·s^–1. After 28 days, softwood cuttings treated with IBA + NAA (3000 + 3000 μmol·L–1) had highest rooting percentage (89.3%) with 5.5 mean roots. Shoot apex and nodal explants of softwood cuttings were pretreated with 0.1% (w/v) ascorbic acid, boric acid, activated charcoal, citric acid, glutamine or polyvinylpolypyrollidone (PVP) for 24 h to remove phenolic compounds before surface disinfestation. Glutamine (Gl) and PVP were equally effective resulting in 60% establishment of shoot apices on MS medium supplemented with 10 μmol·L–1 6-benzylaminopurine (BAP) + 5 μmol·L–1 NAA. Using shoot apices, highest (42.80) number of multiple shoots with 54.33 mm shoot length were obtained on MS + BAP (8.8 μmol·L–1) + IBA (2 μmol·L–1) after 45 days. Shoots were successfully rooted and acclimatized to greenhouse     

Genotype differencies in direct plant regeneration from stem explants ofPopulus tremula in Turkey

Plant regeneration from 9 clones ofPopulus tremula representing diverse genotypes originated from Turkey, has been studied in different media, such as Murashige and Skoog’s Medium (MS), Aspen Culture Medium (ACM) and Woody Plant Medium (WPM) with appropriate supplements of growth regulators. Regeneration efficiency on WPM containing 1 mg/l zeatin using stem explantsin vitro, was higher than on MS and ACM. In this system, the time required for shoot regeneration was 2 weeks, which was shorter by two weeks than that of previous reports. A strong genotype dependence was observed among the tested nine clones. The regeneration system, we describe here, did not involve the callus phase and thus was less prone to somaclonal variation. When adventitious microshoots were cultured on WPM supplemented with 0.5 mg/l or 2 mg/l indole-3-butyric acid (IBA), root formation was obtained after 1 week of culture. Adaptation of regenerated plantletsin vivo was 100%. This system for micropropagation ofPopulus tremula is expected to be suitable for studies on transformation of genes involved in lignin biosynthesis via modification of lignin content. This study was a part of the Project No. 62-02-001 TUBITAK-MAN-GMBAE named “Investigations on Biogenetically Develop Poplar Clones as a Raw Material for Pulp and Paper Industry” and financially supported by General Management of Turkish Pulp and Paper Mills.     

Shoot multiplication and plant regeneration in <Emphasis Type="Italic">Caragana fruticosa</Emphasis> (Pall.) Besser

Different nutrient media can affect in vitro culturing protocols, and experimentation under varied growth conditions is valuable in plants where in vitro methods are in preliminary stages. We carried out the first in vitro propagation studies for the endangered species Caragana fruticosa (Fabaceae). We evaluated various nutrient media for their impact on shoot elongation and axillary bud proliferation using different concentrations of 6-benzylaminopurine (BA) and α-naphthaleneacetic acid (NAA). Shoot elongation was evaluated based on adventitious shoot primary culture and subculture regeneration from Caragana seedlings. Our goal was to improve both micropropagation and regeneration in C. fruticosa. MS nutrient media was superior to 1/2MS macronutrients, DKW, QL, and WPM for shoot elongation and axillary shoot proliferation. Shoots grown on 1/2MS and WPM exhibited some chlorosis, and shoots on QL produced larger leavers than plants growing on normal medium. The shoot proliferation coefficient on MS media supplemented with 2.22 μM BA and 0.44 μM BA + 2.69 μM NAA was significantly higher than that with other treatments in the primary culture. Shoots on 2.22 μM BA showed a higher proliferation coefficient (3.17) than others in the subculture. Shoots were rooted on 1/2MS medium with the addition of different concentrations of NAA. The optimal concentration for rooting was 0.27 μM NAA (74%). Roots exhibited many stout and long root hairs. Survivl of established plantlets was 82% at 30 days after transfer to soil. Plants established in the green house showed normal growth and displayed no apparent morphological differences compared to stock plants.     

35杨微繁殖与叶片不定芽再生研究

以35杨茎段外植体为供试材料,对腋芽微繁殖、叶片不定芽再生、生根以及移植的离体培养技术体系进行了研究,结果表明：获得初始无菌苗的取材以4月取田间杨树新枝茎段外植体为最好;茎段外植体的启动培养基以附加NAA0．1mCL、0．5mg／L6-BA及GA,0．5mg／L的WPM培养基为优;腋芽微繁殖最快的培养基为WPM＋0．2mg／L6-BA＋0．1mg／LIAA＋0．1mg／LIBA;生根培养基以3／5WPM＋0．1mg／LIBA为好;叶片不定芽再生培养基以WPM＋0．2mg／L 6-BA＋0．1mg／LIAA＋0．1mg／LIBA再生频率最高,达92．86％;叶片不定芽在生根培养基上培养20d后获健壮生根苗,移栽成活率达100％。     

Different culture conditions applied to in vitro shoot multiplication of two Eucalyptus benthamii explant sources

Eucalyptus adult material requires more successive subcultures in the in vitro multiplication phase for increased vigor and cellular activity. This study evaluated the endophytic manifestation and shoot multiplication of one 13-year-old Eucalyptus benthamii clone under different culture conditions and used canopy branches(CB) and trunk base material as explant sources. The culture media were wood plant medium(WPM), Murashige and Skoog medium(MS) and JADS(Correia and co-authors medium).Based on the results of the initial multiplication experiment, further tests examined sucrose concentrations and p H. Morphophysiology, dry mass production, endophyticmanifestation and histochemical were determined. Explant sources responded differently to MS and JADS media, but the WPM medium promoted homogeneous development.The responses were similar for both explant sources when sucrose concentrations varied. Shoots died in the absence of sucrose, showed high oxidation at 60 g L-1 and optimal development at 30 g L-1. Endophytes were more evident for shoots from the CB origin. Explant sources responded distinctively to treatment due to physiological and intrinsic genetic factors. Therefore, explant sources, different culture media, sucrose concentration and p H may determine micropropagation success and influence the presence and/or intensity of endophytic manifestation.