Micropropagation of the critically endangered Western Australian species,Symonanthus bancroftii (F. Muell.) L. Haegi (Solanaceae)

A micropropagation protocol was developed for the conservation of the critically endangered Western Australian shrub,Symonanthus bancroftii. It was necessary to screen antioxidant treatments to prevent the occurrence of lethal browning of explants upon excision. Potassium citrate and citric acid (0.1% w/v in a 4:1 ratio) prevented oxidative browning and was superior to the untreated control or other antioxidant treatments tested. Half strength Murashige and Skoog (MS) medium containing 0.5 μM kinetin and 0.25 μM benzyladenine produced three-fold multiplication compared to 1.75×, 1.5×, 1.8× and 1× multiplication for 2.5 μM kinetin + 0.25 μM benzyladenine, 0.5 μM kinetin + 5 μM gibberellic acid, 1 μM kinetin + 3 μM gibberellic acid and half strength MS with no plant growth regulators, over 4 weeks. Root production was achieved with indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (NAA) at 0.5/0.5 μM (31% rooting) and 1.0/1.0 μM (36% rooting), after four weeks. Paclobutrazol (PBZ) at 0, 3.4 (1 mg 1⁻¹), 10.2 (3 mg 1⁻¹), or 17 μM (5 mg 1⁻¹) improved tolerance to desiccation after transfer ofin vitro rooted shoots to soil. PBZ at 10.2 μM increased survival to 90% compared to 50% for those plantlets not treated with PBZ. The acclimatisation period from the glasshouse to the shadehouse was 1 week for plantlets treated with PBZ compared to 4 weeks for plantlets without any PBZ. PBZ at 3.4 μM increased the number of roots per shoot compared to untreated controls. This revised version was published online in June 2006 with corrections to the Cover Date.     

Micropropagation of Chokecherry and Pincherry cultivars

In vitro culture establishment, shoot proliferation and ex vitro rooting responses of chokecherry (Prunus virginiana L.), `Garrington', and pincherry (P. pensylvanica L.f), `Mary Liss' and `Jumping Pound', were examined using various combinations of growth regulators. Dormant winter buds were used as explants. MSMO medium supplemented with 0.49 μM IBA and either 4.44 or 8.87 μM BA was found to be optimal for culture initiation of both species and cultivars. GA₃ (28.89 μM) significantly reduced (p=0.0001) the number of successfully established cultures. BA concentrations 8.87–12.82 μM gave optimal shoot proliferation in chokecherry and 4.44 μM BA in both cultivars of pincherry. Auxin treatments were required for ex vitro rooting of approximately 10 mm long shoots in peat/perlite (1:1 v/v) mixture, at 25 °C, under mist. The best rooting (84%) was obtained with IBA/NAA (9.80/2.69 μM). A commercial rooting powder, Rootone F, containing IBA/NAA (0.057/0.067%) mixture, was also effective (75%). The ex vitro rooted plantlets did not require any additional acclimatization prior to transplanting to the regular greenhouse conditions. This revised version was published online in August 2006 with corrections to the Cover Date.     

李砧木Marianna离体叶片再生体系优化研究

以李砧木‘Marianna’试管苗新梢顶端第1片叶为外植体,研究激素组合、基本培养基种类及外植体类型等对不定芽再生的影响。结果表明:1/2 MS基本培养基和WPM培养基再生率显著高于MS和SH培养基;叶片附带叶柄的外植体再生率和再生不定芽数显著高于叶柄和切除叶柄的叶片外植体;最佳再生培养基为1/2MS+2.0mg/L TDZ+0.1 mg/L IBA+0.25%琼脂+3.0%蔗糖,最高再生率和再生不定芽数分别为81.7%和7.46±1.38个;最佳生根培养基为1/2MS+0.5~1.0 mg/L IBA,能获得96.7%生根率、较高的生根数和根长。     

金线莲组织培养中若干因素的研究

研究了影响金钱莲组培芽的增殖和营养器官分化的几个因素。结果表明:植物细胞分裂素及生长素的种类、浓度和配比对瓶苗茎发育有很大影响,在增殖期使用浓度为1.0mg/L BA、0.5mg/L IBA,器官分化生长期使用浓度为增殖期激素量的三分之一;瓶移植量10～15株;光照量显著影响植株生长期叶片生长,500lx较合适;活性炭明显提高诱导根的生长质量,添加浓度0.5％效果最好。     

Rapid micropropagation of mature wild cherry

Explants taken from the mature vigorous tree of wild cherry (Prunus avium L.) were assayed for their organogenic capacity under various phytohormonal treatments. The highest rate of adventitious shoot multiplication was recorded at a combination of 0.5 mg dm⁻³ 6-benzylaminopurine (BAP) and 0.05 mg dm⁻³ thidiazuron (6.83 shoots per explant). No differences in multiplication rates were found among media supplemented with BAP, BAP + α-naphthaleneacetic acid (NAA) or BAP + indole-3-butyric acid (IBA). Shoot elongation was significantly affected by the concentration of BAP, regardless of auxin addition to medium. Up to 73 % of microshoots rooted after using 0.3 mg dm⁻³ IBA, otherwise the adventitious rooting occurred at reasonable frequencies in all auxin treatments. Regenerated plantlets were successfully hardened ex vitro and continued to grow after the transfer to soil. No morphological aberrations were observed in the regenerates.     

硝酸镧对霍霍巴多芽苗生长的促进作用及植株再生

在增殖培养基(改良MS 2mg／L6-BA 0．5mg／LG3)中添加1～3．5mg／L硝酸镧,对霍霍巴试管苗生长有显著促进作用,2．5mg／L硝酸镧对多芽分化有极显著的促进;在生根培养基(改良1/2MS 3mg／LIBA 1．5mg／LNAA)中,1～2mg／L的La(NO3)3对根的分化有显著的促进作用,生根率提高,最佳浓度为2．0mg／L。过高的浓度对试管苗生长有一定抑制。试验表明,不同器官对硝酸镧的敏感程度不同。取2cm高以上的霍霍巴试管苗,用25mg／L IBA或NAA处理30min,扦插于沙基质中。保持室温20～30℃。50d后揭去覆膜,保持光强3000 lx,相对湿度85％以上。正常管理条件下成活率达75％。     

龙珠果茎段离体培养和组培苗耐盐性分析

为建立龙珠果(Passiflora foetida)的快繁再生体系,以实生苗茎段为外植体,研究了植物生长调节剂对丛生芽诱导、壮苗生根的影响,同时对组培苗的耐盐性进行研究.结果表明,MS+6-BA 0.5 mg/L+NAA 0.05 mg/L培养基有利于诱导丛生芽并促进芽的生长;MS+6-BA 3.0 mg/L+NAA ...     

Influence of growth regulators on plant regeneration from epicotyl and hypocotyl cultures of two groundnut (Arachis hypogaea L.) cultivars

This study was designed to evaluate the effect of phytohormones on plant regeneration from epicotyl and hypocotyl explants of two groundnut (Arachis hypogaea) cultivars. Explants cultured on media with auxins and in combination with cytokinin produced high frequency of callus. After four weeks, callus from these cultures was transferred to medium with cytokinin and reduced auxin, shoot buds regenerated from the cultures. A high rate of shoot bud regeneration was observed on medium supplemented with 2.0 mg/L BAP and 0.5 mg/L NAA. Among the different auxins tested, NAA was found to be most effective, producing the highest frequency of shoot buds per responding cultures. Of the two explants tested, epicotyl was found to be best for high frequency shoot bud regeneration. Multiple shoots arose on MS medium supplemented with BAP or kinetin (1.0–5.0 mg/L) plus IBA (1.0 mg/L), with maximum production occurring at 5.0 mg/L. The elongated shoots developed rootsin vitro upon transfer to MS medium supplemented with NAA or IBA (0.5–2.0 mg/L) and kinetin (0.5 mg/L) for 15 days.In vitro produced plantlets, were transferred to soil and placed in a glasshouse developed successfully, matured, and set seeds.     

Indole-3-butyric acid and myo-inositol impacts on in vitro rooting of the cherry rootstocks CAB-6P and Gisela 6

The present study investigates the effects of indole-3-butyric acid (IBA) alone and in combination with myo-inositol on in vitro rooting and biochemical responses in the cherry rootstocks CAB-6P (Prunus cerasus L.) and Gisela 6 (Prunus cerasus × Prunus canescens). For the CAB-6P rootstock, the best results for root number (6.31), fresh mass (FM), dry mass (DM), and rooting percentage (100 %) were obtained on Murashige and Skoog (MS) medium with 2 mg dm^?3 IBA and maximum root length (30.57 mm) was obtained at 1 mg dm^?3 IBA. Myo-inositol suppressed the positive effects of IBA on root length. In the Gisela 6 explants, the inclusion of 2 mg dm^?3 IBA together with 0.5 mg dm^?3 of myo-inositol in the culture medium significantly enhanced root number (9.91) and root FM and DM. The root length was maximum in the combination of the lowest IBA and myo-inositol concentrations (0.5 mg dm^?3). The rooting percentage was the greatest (100 %) with the application of 1 mg dm^?3 IBA alone. In both explants, the application of IBA alone or in combination with myo-inositol resulted in a lower leaf proline content in comparison with the control (without growth regulators). The maximum leaf chlorophyll content was at 1 mg dm^?3 IBA in the CAB-6P whereas at 2 mg dm^?3 IBA and 1 mg dm^?3 myo-inositol in Gisela 6. Addition of myo-inositol mostly increased sugar content in comparison with control or IBA alone in both rootstocks.     

Larval food affects oviposition preference,female fecundity and offspring survival in Yponomeuta evonymellus

1. Yponomeuta evonymellus is a monophagous moth that feeds on Prunus padus which is native to Europe. In recent years, larval feeding and egg clusters have also been observed on non‐native Prunus serotina plants; however, survival of larvae on this new host is very low. 2. The objective of the present study was to determine how the feeding of larvae on each of the two host plants impacts oviposition, offspring survival and fecundity in Y. evonymellus. Our hypothesis was that, under controlled conditions, females will lay eggs on the host on which they fed as larvae. We also hypothesised that the lower survival of young larvae feeding on P. serotina was due to the smaller buds and leaves present in this species, relative to those of P. padus. 3. A dual‐choice experiment conducted under laboratory conditions demonstrated that females preferentially chose to oviposit on the plant species on which they fed as larvae. In the experiment, potential fecundity and offspring survival were significantly higher on P. padus than on P. serotina. The reduced performance of Y. evonymellus on P. serotina was correlated with a smaller bud mass and volume, lower leaf mass and surface area, and difficulty in constructing a protective tent against unfavourable weather conditions. 4. In summary, the identity of the host plant species during larval feeding determines adult oviposition preference for that host species. The survival of larvae on P. serotina growing in the nature is low, but for phenology‐related reasons.     

The effect of triacontanol on micropropagation and on secretory system of Thymus mastichina

Shoot multiplication of Thymus mastichina L. was achieved on media containing 0.1 mg l^–1 6-benzyladenine and/or 0.1 mg l^–1 indole-3-butyric acid, or in hormone-free medium (control). The growth of plantlets, the production and composition of the essential oil, the density and secretory stage of glandular hairs have been evaluated in the presence and absence of growth regulators and triacontanol. We observed a positive effect of triacontanol on the growth of micropropagated plantlets using different conditions. Media with different levels of BA, IBA and TRIA resulted in no differences in the composition of the essential oil produced by plantlets. The major components of the oil were 1,8-cineole and linalool. An increase in the oil yield was observed especially when triacontanol was added to hormone-free medium. There was no correlation between changes in the oil yield and glandular hairs density, but the yield was dependent on the secretory stage of the glands.     

利用微嫁接技术促进麻疯树再生不定芽的生长

该研究以麻疯树种子实生苗的小芽和芽条为接穗,以带有胚根的实生苗下胚轴为砧木进行无菌微嫁接,试图建立新的有效微嫁接方法,解决农杆菌介导的麻疯树遗传转化体系中再生的转化不定芽难以顺利发育成完整植株的问题。结果表明:(1)抗生素对嫁接苗的生长有显著的抑制作用。(2)进行微嫁接所用砧木的苗龄以5d为宜。(3)进行微嫁接时适宜采用的砧木类型为带有部分胚根的下胚轴。(4)嫁接苗在0.3mg/L IBA+2mg/L谷氨酰胺+1/2MS培养基上的生长效果最好。(5)嫁接苗的移栽成活率最高可达76.40%。(6)以小芽或芽条为接穗的嫁接苗均可正常生长。该研究建立的麻疯树微嫁接体系,为解决麻疯树转化不定芽或芽条生长发育困难的问题提供了一条新的途径。     

Host specificity of trail marking to foliage by eastern tent caterpillars, Malacosoma americanum

The recruitment trail marking behavior of eastern tent caterpillars (Malacosoma americanum Fabr.) was modified by rearing them on plants which they do not usually attack in nature. Caterpillars reared on one of two nonhosts (Prunus avium (L.) L. or Quercus coccinea Muenchh.) marked pheromone trails to foliage of their rearing plant, whereas caterpillars reared on a natural host plant (Prunus serotina Ehrh.) did not mark trails to nonhost foliage. Caterpillars preferred host to nonhost foliage, regardless of their rearing history. The degree of trail marking was correlated with suitability of foliage for larval growth. The results indicate that trail marking behavior is a response to relative rather than absolute food quality, but that preference behavior is more rigidly programmed to favor the optimal food.

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Zusammenfassung Das Rekrutierungs-Spurmarkierungsverhalten von Malacosoma americanum Fabr. wurde durch die Zucht der Raupen auf Nichtwirtspflanzen modifiziert. Die Bevorzugung der Wirtspflanze jedoch wurde nicht verändert. Das Spurmarkierungsverhalten wurde im Laboratorium quantifiziert, indem die Zahl der markierten Abschnitte eines Kartonstreifens gezählt wurde, auf dem die Raupe von einem Ende zum andern kroch. Das Präferenzverhalten wurde geprüft, indem Blattscheiben von Wirts-und Nichtwirtspflanzen an einem Ende des Kartonstreifens befestigt wurden. Die Raupen markierten Spuren zu Nichtwirtspflanzen (Prunus avium oder Quercus coccinea) nur, wenn sie darauf gezüchtet worden waren. Andererseits war die Spurmarkierung auf Wirtspflanzen (Prunus serotina) hin intensiv unabhängigig von der Art der Zucht. Ebenfalls unabhängig von der Aufzucht war die Bevorzugung von P. serotina vor Nichtwirtspflanzen in Wahlversuchen. Präferenz und Spurmarkierung waren korreliert mit der Eignung der Blätter für Raupenwachstum. Die Resultate zeigen, dass das Spurmarkierungsverhalten mehr eine Reaktion auf relative als auf absolute Futterqualität ist, dass jedoch Präferenz strenger auf optimales Futter programmiert ist.

     

An efficient in vitro plantlet regeneration of <Emphasis Type="Italic">Cryptocoryne wendtii</Emphasis> and <Emphasis Type="Italic">Cryptocoryne becketti</Emphasis> through shoot tip culture

An efficient micropropagation protocol was established for Cryptocoryne wendtii and Cryptocoryne becketti using shoot tips explants. Multiple shoots were induced from shoot tip explants of both species cultured on agar-gelled as well as liquid MS medium supplemented with 0.5 mg/L BA and 0.2 mg/L IBA (proliferation medium). The multiple shoots of both the species formed on agar-gelled as well as liquid medium were vigorously growing with well-developed roots and leaves after 4 weeks of culture. Highest number of multiple shoots was obtained from shoot tip explants of both the species cultured in liquid proliferation medium after 4 weeks of culture. The shoot tip explants of C. wendtii and C. becketti, that were cultured in liquid proliferation medium (2 weeks) followed by culturing on agar-gelled proliferation medium (2 weeks) also produced the multiple shoots. Shoot tips cultured on agar-gelled medium produced the least number of multiple shoots after 4 weeks of culture. Histological study did not show any abnormalities in the leaves of in vitro plantlets of both the species, cultured in agar-gelled and liquid proliferation medium. The leaves of the in vitro plantlets formed normal mesophyll cells and vascular bundles. More than 95% of the acclimatized plantlets grew vigorously without any morphological abnormalities.     

Effect of vessel type and growth regulators on micropropagation of Capsicum annuum

Leaves from 14-d-old Capsicum annuum L. cv. Anaheim seedlings were cultured on Murashige and Skoog (MS) medium containing different combinations of indole-3-acetic acid (IAA) and 6-benzyladenine (BA). After 3 months, cultures were transferred to new medium where BA was replaced with 9 μM isopentenyladenine (2iP) to enhance the growth of shoot buds. Developing shoots were elongated and rooted on MS medium enriched with 9 μM indole-3-butyric acid (IBA). All cultures were maintained in 250 cm³ baby jars covered with a clear polypropylene lid with or without microporous polypropylene membrane. Vessel type and plant growth regulators significantly affected callus morphogenic appearance, organogenesis and in vitro plantlet growth. Ventilated vessels supported photomixotrophic culture and improved regeneration and growth of plantlets. Higher plantlet dry mass and content of photosynthetic pigments, and lower stomatal density of plantlets grown in ventilated than in non-ventilated vessels facilitated ex vitro acclimation and growth.     

Influence of plant growth regulators on the growth and essential oil content of cultured Lavandula dentata plantlets

Micropropagation of L. dentata L. through shoot-tips (ca. 5 mm) was achieved successfully. Micropropagated plantlets were cultured without plant regulators in the culture medium (control) or in media containing 0.1 mg l⁻¹ of 6-benzyladenine (BA) and/or indole-3-butyric acid (IBA). These plantlets were examined for their essential oil content and composition in relation to growth rate and density and secretory or postsecretory stage of glandular hairs at five weeks of culture. The growth rates of these plantlets were not always correlated with their essential oil content (0.26%–0.65% v/w). However, all cultured plantlets showed a positive correlation between oil accumulation and the percentage of glandular hairs in secretory stage. Quantitative changes in the major monoterpene components (1,8-cineole, fenchol, borneol and camphor) and sesquiterpene content of plantlet oil, were also observed in response to the effect of varying growth regulator concentration in the culture medium. The influence of this effect on HMG-CoA reductase activity of cultured plantlets is also discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Abscisic acid and salinity stress induced somaclonal variation and increased histone deacetylase (HDAC) activity in <Emphasis Type="Italic">Ananas comosus</Emphasis> var. MD2

Somaclonal and phenotypic variation caused by genetic and/or epigenetic modifications, are a valuable source of genetic variation to improve desirable polygenetic traits in crops. In this study, we induced somaclonal variation in vitro pineapple (Ananas comosus var. MD2) through hormonal induction, NaCl, and abscisic acid (ABA) supplementation. Our results showed that supplementation of high concentration of 6-benzylaminopurine (4.0 mg/L BAP) alone or combined with indole-butyric acid (IBA) produced the highest percentage of dwarf variants (100%). Murashige and Skoog (MS) media containing 4.0 mg/L BAP plus 2.0 mg/L IBA produced the shortest plantlets (1.9?±?0.1 cm). In comparison, MS media containing 1.0% NaCl induced formation of dwarf plantlets with a mean plantlet height of 1.4?±?0.3 cm, whereas 1.0 mg/L ABA generated plantlets with a mean plantlet height of 1.7?±?0.1 cm. We then analyzed the histone deacetylase (HDAC) enzyme activity for dwarf and non-dwarf plantlets. In general, dwarf plantlets exhibited higher HDAC activity than non-dwarf plantlets. The highest HDAC activity (109, 333.33?±?4.40 ng/min/mg) was recorded for dwarf plantlets grown on media supplemented with 1.0 mg/L ABA. The dwarf variants also underwent phenotypic recovery to normal phenotype within 8 months after transferred to MS basal media. No ploidy alteration was detected in these dwarf plantlets after analyzed by flow cytometry. Taken together, although the generated dwarf plantlets showed higher HDAC activity compared to non-dwarf plantlets, their capability of reverting to non-dwarf phenotype suggested that it might be due to epigenetic modulation.     

Additive effects of three auxins and copper on sorghum in vitro root induction

A healthy root system is vital for tissue culture plantlet survival and rapid adaptation from the in vitro microenvironment to glasshouse conditions. Optimization of the root induction medium is an effective way to promote root induction and elongation. Levels of three auxins (α-naphthaleneacetic acid [NAA], 3-indoleacetic acid [IAA], and 3-indolebutyric acid [IBA]) and copper sulfate (CuSO₄) have been investigated in a series of experiments with a sorghum inbred line, Tx430. Significant improvement in root proliferation and shoot growth were observed on Murashige and Skoog (MS) medium supplemented with 1 μmol/L CuSO₄, 1 mg/L NAA, 1 mg/L IAA, and 1 mg/L IBA. On average, one explant (the original in vitro-derived shoot) of Tx430 regenerated 56.7 roots, which was 20-fold higher on the optimal medium than on MS control medium. Another tested genotype SA281 showed similar response patterns as Tx430 across media. In addition, 100% of Tx430 and SA281 plantlets originating from the optimized root induction medium all survived after being transferred to potting soil in the glasshouse. The results demonstrate that a combination of auxins (NAA, IAA, and IBA) and CuSO₄ together at optimal concentrations provide additive effects on promoting root proliferation and explant growth of in vitro sorghum in root induction medium, and subsequently resulted in 100% survival rate of plantlets ex tissue culture. Compared with two published and frequently used root induction media, the optimized medium significantly enhanced root induction and plantlet growth.     

Shoot regeneration from leaves of Prunus serotina Ehrh. (black cherry) and P. avium L. (wild cherry)

Leaves excised from shoot cultures of Prunus avium cvs. F12/1 and Charger and genotype 1908, and from five genotypes of P. serotina and two hybrids of P. avium×P. sargentii developed shoots on Woody Plant medium (WPM) supplemented with either benzyladenine (BA) or thidiazuron (TDZ). Regeneration in both P. avium 1908 and a genotype of P. serotina was improved using TDZ rather than BA in the medium. Regeneration occurred more frequently in P. serotina if leaves were cultured on medium with WPM rather than modified Driver and Kuniyuki walnut medium. The proportions of leaves that regenerated varied between genotypes of the same species. Regenerated shoots of both P. avium and P. serotina developed into shoot cultures following transfer to the media used to produce the shoot cultures used as explant sources. Received: 10 July 1996 / Revision received: 11 November 1996 / Accepted: 6 January 1997     

Direct somatic embryogenesis in a selected tea clone, `TRI-2025' (Camellia sinensis (L.) O. Kuntze) from nodal explants

An efficient method for the in vitro propagation of a tea (Camellia sinensis (L) O. Kuntze) clone, `TRI-2025', from somatic embryos is described. This technique involves two phases; the induction of adventitious buds from nodal cuttings followed by the development of somatic embryos. Single nodal cuttings were excised from 1-year-old in vitro axenic cultures and inoculated on MS medium with different combinations of IBA/BAP/GA₃. Induction of multiple shoots from nodal explants occurred on MS medium with 0.5 mg l^–1 BAP, 0.1 mg l^–1 IBA and 0.0 mg l^–1 GA₃ within 6 weeks of incubation. The cultures with multiple shoots were transferred to fresh medium, incubated for 120 days and transferred to MS medium with half-strength macro nutrients, full-strength micronutrients and vitamins and no growth regulator. The direct induction of somatic embryos without callus formation occurred on this medium at 60% frequency within 4 weeks. The production of embryos continued upon transfer of the cultures to fresh medium and a four- to eightfold multiplication rate was obtained during each 6-week culture cycle. The plantlets from these embryos were acclimatised with a 90% success rate. All plants were vigorous and hardy, with well-developed tap-root systems. Received: 20 July 1996 / Revision received: 2 January 1998 / Accepted: 19 January 1998