Albino inflorescence proliferation of Dendrocalamus latiflorus

Summary Inflorescence proliferation is a plant tissue culture technique that, can be used to obtain in vitro inflorescences year-round without the intervening development of vegetative organs. In this study, we used albino mutant inflorescences of Dendrocalamus latiflorus as the original explant material to investigate, the effect of plant growth regulators on long-term inflorescence proliferation. The albino inflorescences proliferated on solidified Murashige and Skoog (MS) basal medium supplemented with thidiazuron (TDZ), and the optimal concentration for successful long-term inflorescence proliferation was 0.45 μM TDZ. A combination of α-naphthaleneacetic acid (NAA) with 0.45 μM TDZ inhibited the inflorescence proliferation. Inflorescences cultured on a TDZ-free medium supplemented with 26.82 μM NAA rooted in 21 d, vegetative shoots formed by 42 d and, in one case, flowering occurred after 63 d. The auxins 2,4-dichlorophenoxyacetic acid (2,4-D, 4.52 μM) and pieloram (4.14 μM) induced shoot formation. The protocol described can be used to produce large numbers of mutant inflorescences within a relatively short period of time.     

Effect of cyanobacterial extracellular products on high-frequency in vitro induction and elongation of Gossypium hirsutum L organs through shoot apex explants

The challenging task of bringing high efficiency transformed plants attracts lot of attention in recent times. In search for this, there have been many attempts made using, different techniques like tissue culture and plant breeding methods. Here we report a suitable alternative facile route, where cyanobacterial extracellular products are utilized as growth regulators and its performance validated on Gossypium hirsutum L. MS medium is tested with cyanobacterial extracellular products of Nostoc ellipsosporum, Dolichospermum flos-aquae and Oscillatoria acuminata .Our best results show that the addition of O. acuminata extracellular product with plant growth hormones gives the excellent induction and elongation in cotton. In addition to this, the multiple shoot was obtained on MS medium fortified with 1.0 mg L^?1 BA with 8% O. acuminata and 1.5 mg L^?1 TDZ with 12% O. acuminata. High frequency of shoot elongation supplemented with MS medium, iP 2.5 mg L^?1 and 16% O. acuminata and root production MS medium fortified with 12% O. acuminata best responsible for regeneration in cotton plants. The rooted plants were hardened and transferred to soil with 90% survival rate.     

文心兰类原球茎的愈伤组织诱导及其植株再生

该研究首次以文心兰的类原球茎( protocorm-like bodies, PLBs)为外植体进行愈伤组织诱导及其植株再生培养,并分析了不同浓度的TDZ和2,4-D配比对愈伤组织增殖的影响。结果表明：以1/2MS为基本培养基,添加1 mg.L-1 TDZ与3 mg.L-12,4-D,从接种的 PLBs上可以诱导出乳白色的、较疏松的愈伤组织,诱导频率达到100％。愈伤组织继代培养时,在2,4-D浓度为0.5~2.0 mg.L-1的范围内,其增殖主要受TDZ浓度的影响,TDZ浓度从1.0 mg.L-1降低到0.5 mg.L-1,愈伤组织鲜重增殖倍数显著增加,由最低的4.50倍增加到最高的6.04倍。愈伤组织增殖的最适培养基为1/2MS ＋0.5 mg.L-1 TDZ ＋1.0 mg.L-12,4-D。将在最适愈伤组织增殖培养基上继代培养约1个月的愈伤组织转移到T2培养基(3.5 g.L-1花宝1号＋20 g.L-1红薯＋25 g.L-1香蕉＋1 g.L-1 tryptone ＋20 g.L-1蔗糖＋3.5 g.L-1 phytagel)上,黑暗培养1个月后,每克鲜重的愈伤组织约诱导出1328.67个PLBs。将诱导出的PLBs转移到新鲜的T2培养基上光照培养1个月,萌发率为90.12％。而将小植株转移到添加1 g.L-1活性炭的1/2MS培养基上,成苗率达到100％。该研究结果成功建立了文心兰的高频愈伤组织诱导及其植株再生体系,为文心兰基因工程育种提供了一个高效、稳定的转化受体系统。     

Direct differentiation of somatic embryos on different regions of intact seedlings of Azadirachta in response to thidiazuron

Direct differentiation of somatic embryos occurs in high-frequency and at high density in response to 1.0 microM TDZ, on different regions-hypocotyl, epicotyl, cotyledonary-node, cotyledons and leaves-of intact seedlings of Azadirachta. One-week-old seedlings on this medium exhibited stress symptoms as visible by the loss of root formation and reduction in the elongation of hypocotyl and epicotyl. Globular somatic embryos were more abundant on hypocotyl, epicotyl, stem tip and leaves. The arrest of embryos at this stage was possibly due to their presence in high density. Well-developed somatic embryos were present on the cotyledons and the cotyledonary-node. These embryos on isolation and transfer to hormone-free medium regenerated readily to form plantlets. The possible role of stress in thidiazuron-induced somatic embryo formation is discussed.     

Mass propagation of ornamental gentian in liquid medium

An efficient system for clonal mass propagation in liquid culture was established for the propagation of ornamental gentian. In a test of the requirements for three cytokinins [6-benzylaminopurine, N-(2-chloro-4-pyridyl)-N′-phenylurea and N-phenyl-N′-1,2,3-thiadiazol-5-yl urea (TDZ)] in combination with 1-naphthaleneacetic acid (NAA), we found that effective propagation of shoots occurred with 0.01 mg l^–1 TDZ in a 300 ml conical flask that contained 100 ml of medium. The propagation of shoots was also affected by the concentrations of macronutrients (KNO₃, NH₄NO₃ and CaCl₂) and sucrose in Murashige and Skoog's (MS) medium, and it was influenced to some extent by the speed of agitation on an orbital shaker. The most efficient propagation of shoots was achieved in full-strength MS medium supplemented with 0.01 mg l^–1 TDZ and 20 g l^–1 sucrose with agitation at 150 rpm. The propagation of shoots was maximal after 6 weeks of culture (140 shoots from five nodal segments in one flask). Large-scale propagation in a 5-l fermenter was attempted using 3 l of MS medium that contained 0.01 mg l^–1 TDZ and 20 g l^–1 sucrose. More than 2,000 shoots were obtained in the fermenter in 5 weeks following the initial cultivation of five nodal segments for 6 weeks in one 300-ml flask. The shoots that had propagated in the fermenter were transferred directly to soil without prior rooting in vitro and were easily acclimatized within 1 month. Received: 7 October 1997 / Revision received: 16 January 1998 / Accepted: 30 January 1998     

Efficient in vitro regeneration systems for Vaccinium species

Efficient protocols for shoot regeneration from leaf explants suitable for micropropagation as well as for the development of transgenic plants were developed for blueberry (Vaccinium corymbosum) and lingonberry (Vaccinium vitis-idaea) cultivars. Nodal segments were used to initiate in vitro shoot cultures of lingonberry cultivar ‘Red Pearl’ and southern highbush blueberry cultivar ‘Ozarkblue’. In order to develop an optimized regeneration procedure, different types and concentrations of plant growth regulators were tested to induce adventitious shoot regeneration on excised leaves from micropropagated shoots of both cultivars. The effect on percentage regeneration and number of shoots per explant was investigated. Results indicated that zeatin was superior to TDZ and meta-topolin in promoting adventitious shoot formation. A concentration of 20 μM zeatin was most effective in promoting shoot regeneration in both cultivars, in case of ‘Red Pearl’ along with 1 μM NAA. Shoots were either allowed to root in vitro on medium containing IBA or NAA or ex vitro in a fog tunnel. IBA was superior to NAA for induction of root development in vitro in both Vaccinium cultivars. Ex vitro rooting under high humidity was tested with cuttings from mature field-grown plants, from acclimatized tissue culture derived plants and with unrooted in vitro proliferated shoots planted directly. It was found that in vitro shoots rooted better under fog than cuttings from the other plant sources and rooting was equivalent to that achieved in vitro.     

萝卜带柄子叶高频再生体系的建立

以11份萝卜（Raphanus sativus）基因型为材料进行子叶离体培养研究,筛选出具有较高再生率的基因型进行实验,考察基因型、外植体类型、激素配比和苗龄等因素对萝卜再生的影响。结果表明：萝卜离体再生的最佳外植体为全子叶-叶柄,最适苗龄为4天,最适培养基为MS＋6mg·L-16-BA＋0.05mg·L-1NAA,再生率高达86.95%,再生系数为1.80。该研究为进行萝卜遗传转化实验奠定了良好基础。     

草果组织培养快速繁殖育苗研究

以草果（Amomum tsao-ko Crevost et Lemaire）茎尖为外植体,MS为基本培养基,探讨不同浓度的培养基因子,对草果不定芽的诱导、增殖分化、生根情况和试管苗移栽成活率的影响.结果表明：①以MS＋6-BA 6 mg/L＋NAA 0.1 mg/L＋TDZ 0.05 mg/L的培养基对不定芽增殖分化效果较好,增殖倍数达到2.34,不定芽叶色绿,苗粗壮,整体感最好.②糖浓度对草果不定芽分化增殖有一定影响,以糖浓度为30～35g/L增殖分化效果较好.③在草果不定芽生根中,以1/2MS＋IBA 0.2 mg/L、1/2MS＋NAA 0.2 mg/L效果较好.出根率较高,须根最多,平均根数最多,移栽成活率为100%.     

Adventitious shoot regeneration from leaf explants and stem nodes of Lilium

A method for the regeneration of lily plantlets (Lilium spp.) through different morphogenic pathways is described. Plant regeneration was obtained from in vitro cultured leaves of four lily hybrids, cultured on Murashige and Skoog's basal medium supplemented with cytokinins (TDZ and BA) and auxins (NAA and IBA) at different concentrations. Direct shoot regeneration occurred with all tested media for the Asiatic lilies `Elite' and `Pollyanna' and also for the Oriental hybrid `Star Gazer'. Callus developed on TDZ-enriched medium from leaf segments of L. longiflorum cv. `Snow Queen' regenerated by direct organogenesis. This occurred on a medium with auxin/ cytokinin balance which was lower than other genotypes. There were fewer problems of sterilization with leaves from sprouted bulbs than in vitro scale culture. This suggests that the leaf-segments obtained in this way could be an alternative to the scales as a source of material for propagation. A protocol for micropropagation based on bulblets from in vitro shoot-tip-derived stem nodes was also used. The development of pseudo-bulbets is particularly advantageous since it allows for structures characterised by absent or low dormancy. Regenerated shoots have been rooted and successfully acclimatized to greenhouse conditions where they flowered after the second year giving plants with true-to-type shape and colour.     

Callus mediated shoot organogenesis and regeneration of cytologically stable plants of Ledebouria revoluta: An ethnomedicinal plant with promising antimicrobial potency

Ledebouria revoluta are important ethnomedicinal plant found in India and South Africa. Micropropagation via indirect shoot organogenesis had been established from three types of explant (i.e. scale leaf, leaf lamina and root) of L. revoluta. Scale leaf was found superior as compared to leaf lamina and root explant with respect to their organogenic callus induction potentiality. Murashige and Skoog (1962) [MS] media supplemented with 3.0?mg?L^?1 2,4-dichlorophenoxyacetic acid, 0.75?mg?L^?1 β-naphthoxyacetic acid were best effective for inducing organogenic callus. Maximum 17.0?±?0.52 bulblets were induced from about 500?mg of callus within 42–46?days sub-culturing on a medium containing 0.75?mg?L^?1 kinetin. The bulblets were matured (86.7% success) after one month culture on the same medium composition. The best result of in vitro root induction with 100% response and 8.4?±?0.31 roots per bulb was achieved after 18?days of implantation on MS medium containing 2.0?mg?L^?1 indole-3-butyric acid. Plantlets were acclimatized with a 96.0% survival rate. Chromosomal studies revealed cytological stability of callus cells and all regenerants containing 2n?=?30 chromosomes, same as parental plants. Antimicrobial activity of L. revoluta was tested against two Gram-positive bacteria, three Gram-negative bacteria and two fungi. The methanol and ethanol extract proved more effective against bacteria, whereas acetone and chloroform extract shows potential anti-fungal activities. Present protocol can be applied reliably to produce uniform planting materials in large scale. In addition, this efficient indirect regeneration pathway via callus culture opens a way for improvement through genetic transformation.