Tissue culture for the international transfer of potato genetic resources

The use of tissue culture techniques for the international movement of potato clonal germplasm was studied. “Multi-meristem” cultures were established from virus-free plants by procedures described earlier by the authors. Well developed plantlets, regenerated aseptically from “nodal cuttings” of shoots produced in multi-meristem cultures, were used for international transfer. The medium contained the Murashige-Skoog mineral and vitamin components, with 2% sucrose, and was supplemented with 2 mg/l calcium pantothenate and 0.2 mg/l gibberellic acid. The cultures survived the mail shipment when 1% agar medium and small test tubes were used; polystyrene containers reduced damage due to abrupt temperature changes. At the receiving end, higher survival rates during the recovery of plants was achieved through potting of plantlets regenerated from nodal cutting cultures. A total of 43 pest and disease-free potato clones have been distributedin vitro from CIP to 10 different countries. The training of technicians from developing countries played an important role in the application of these methods.     

In vitro propagation and regeneration of an industrial plant kenaf (Hibiscus cannabinus L.)

The present study report a protocol for the efficient in vitro propagation of kenaf (Hibiscus cannabinus L., an industrial crop having high cellulosic fiber content) on hormone free MS medium using the shoot apex and nodal explants. Shoot tips and nodes were isolated from 15 days old seedlings cultivated on MS medium. Different combinations and concentrations of auxin/cytokinin were used and added to the MS medium to assess the shoot and root induction of theses explants. Several subcultures were drived in order to enhance the multiplication rate. Healthy and well developed in vitro propagated shoots were transferred for acclimatization under greenhouse conditions in pots filled with different substrates (sand + compost or perlite). Our results showed that shoots could elongate and root within 4-6 weeks on MS basal medium without any callus formation. However, addition of growth regulators to the MS medium leaded to a decrease in shoot and root induction rates. Indeed, the highest shoot regeneration frequency (90.5%) was obtained on MS control medium. Elongated shoots were transferred onto the same hormone free MS medium using five subcultures where the multiplication rate reached the highest value (3.66) at the fifth and last step. The in vitro rooted plantlets were acclimatized in greenhouse and successfully transplanted to natural conditions with 70% survival.     

In vitro plant regeneration from decapitated embryonic axes of Clitoria ternatea L.—An important medicinal plant

In vitro clonal propagation of Clitoria ternatea has been achieved by employing decapitated embryonic axes (DEAs) explants. The explants induced multiple shoots on cytokinin-containing medium. Several cytokinins [6-benzylaminopurine (BAP), 6-furfuryl aminopurine (KIN) and thidiazuron (TDZ)] were assayed. The best response was achieved with 2 mg l⁻¹ BAP in which 100% of cultures produced 6.0 ± 0.14 shoots per explant. MS + 1 mg l⁻¹ gibberellic acid (GA₃) was the most suitable for shoot elongation. Regenerated shoots were rooted in half-strength Murashige and Skoog (MS) medium with 0.2 mg l⁻¹ indole-3-butyric acid (IBA). Plantlets were successfully acclimatized and established in soil, and they were morphologically indistinguishable from the source plant. The plantlets attained maturity and flowered normally. The efficient regeneration protocol reported here provides an important method of micropropagation of this plant. Furthermore, this protocol may be used for genetic transformation of this valuable medicinal plant for its further improvement.     

Genetic stability of long-term micropropagated Opuntia ficus-indica (L.) Mill. plantlets as assessed by molecular tools: Perspectives for in vitro conservation

Randomly amplified polymorphic DNA markers (RAPD) were employed to assess the level of genetic stability of long term micropropagated prickly pear (Opuntia ficus-indica) plantlets.Thirteen micropropagated plantlets were chosen from a clonal collection of shoots that originated from a single mother shoot. This clonal collection had been maintained under in vitro culture conditions for at least 5 years, as achieved for the time by axillary branch multiplication in Opuntia ficus-indica.Twenty arbitrary primers were used to compare RAPD patterns between in vitro raised material and the mother plant. Only 11 primers were found to yield distinct and reproducible amplification products resulting in a total of 87 amplified products, out of which 82 bands were monomorphic across all the plantlets and 5 showed polymorphisms.Cluster analysis performed on the basis of similarity indices indicated that all micropropagated plantlets and their mother plant grouped together in one major cluster with a 91% level of similarity.Low level of genetic variation has been detected, as polymorphic bands accounted for just 2.79% of the total genetic variation. This very low level of genetic variation, despite more than 5 years of in vitro culture, demonstrates the genetic stability of Opuntia ficus-indica and indicates that the axillary branch multiplication method is highly reliable for the multiplication of genetically true-to-type plant material.The high degree of clonal fidelity detected here, recommend the use of axillary-branching micropropagation technique for the safe in vitro conservation of prickly pear interesting genetic resources.     

Light effects on the growth and morphogenesis of potato(Solanum tuberosum) in vitro: A review

Growth, morphogenesis, and tuberization of potato tissuesin vitro are affected by light. Measurements of the various aspects of light that control development and growth of potato are outlined. Physical parameters like light sources, delivery of the light source, and the degradation of culture media by light are discussed. Irradiance, photoautotrophic growthin vitro, spectral wavelength, and photoperiod modify the responses of potato tissues in culture. Acclimatization of tissue culture plantlets, vegetative growth, and the production, quality, and dormancy of microtubers are modified by light. New light sources such as light-emitting diode (LED) lamps are becoming available forin vitro research and for micropropagation of potato. Pulsed or chopper light has the potential to save energy costs. Light effects on potato protoplasts, anther culture, virus eradication, andin vitro conservation are discussed. Potential new research areas are the effect of the spectral quality of light on regeneration of shoots and somatic embryosin vitro, end-of-day red and far-red light treatments, axillary shoot formation in cultured plantlets, and the use of LEDs. The influence of monochromatic spectral filters on growth and development of potatoes in tissue culture could potentially lead to improvements in productivity. The relationship between daily quantum light integral and photoperiod and their effects on growth and morphogenesis of the potato will provide some useful areas of research.     

Photoperiod,gibberellic acid,and kinetin,in potato flower differentiationin vitro

To inducein vitro floral differentiation on potato plantlets, one cm long apical explants cv. Marijke were excised and aseptically cultured in a semi-solid medium containing Murashige-Skoog salts supplemented with 0.3 mg/l indoleacetic acid; with or without one mg/l gibberellic acid (GA); 0.3, 3.0 or 30.0 mg/l Kinetin (K); 20, 40 or 60 g/l sucrose (S) and 8% agar, pH 5.7. After a five week growing period at 26–28 C with daily light PAR 35 μE/m²/sec, 14 or 24 h daylength (DL), flower buds developed with exposed sepals and an abscission zone in the peduncle. Statistical significance was found when the variation factors (GA, K, S, and DL) were analyzed individually or in combination for number and weight of floral buds. Absence of GA favored the number of buds/plant, and the interaction of continuous light with a culture medium containing 0.3 or 3.0 mg/l kinetin and 40 g/l sucrose induced the highestin vitro “yields” in number and weight of flower buds (6 per plant and up to 14 mg/bud), followed by premature abscission. In a similar experiment, to prevent such abscission, plants from five week old tissue culture were transferred to soil and maintained at 24 h DL and 26–28 C, but flower bud abortion could not be avoided. These results demonstrate the importance of manipulating exogenous factors (growth regulators, sucrose, photoperiod) to inducein vitro specific organogenesis in potatoes.     

Screening and quantification of an antiseptic alkylamide, spilanthol from in vitro cell and tissue cultures of Spilanthes acmella Murr.

The study revealed, for the first time, accumulation of spilanthol, an antiseptic alkylamide, in in vitro cultures of Spilanthes acmella Murr., a medicinal plant of immense commercial value. To achieve this, in vitro shoots were regenerated via direct organogenesis from leaf-disc explants of Spilanthes. Shoots were induced in the presence of N⁶-benzylaminopurine (BAP) alone or in combination with either α-naphthalene acetic acid (NAA) or Indole-3-acetic acid (IAA) in Murashige and Skoog medium. The best treatment for shoot regeneration was MS + BAP (5.0 μM) + IAA (5.0 μM), which promoted adventitious shoot proliferation in >82% cultures with an average of 5.3 shoots per explant. Regenerated shoots rooted spontaneously with a frequency of 100% on half strength MS medium (major salts reduced to half strength) containing 50 g l⁻¹ sucrose. The plantlets were acclimatized successfully with 90% survival rate. Additionally, ploidy stability of the regenerated plants was assessed by flow cytometry which showed that all investigated plants had the similar ploidy as that of the mother plant. For spilanthol identification, peaks eluted from HPLC were analyzed by mass spectrometry with its characteristic fragmentation pattern. For quantification studies, calibration curve was generated, which revealed a higher amount of spilanthol content (3294.36 ± 12.4 μg/g DW) in the leaves of in vitro plants compare to those of in vivo plants (2703.66 ± 9.6 μg/g DW of spilanthol). An efficient multiplication frequency, ploidy stability and enhanced spilanthol accumulation ensure the efficacy of the protocol developed for this industrially important medicinal plant.     

An improved and efficient micropropagation of Eclipta alba through transverse thin cell layer culture and assessment of clonal fidelity using RAPD analysis

An improved and efficient in vitro regeneration system has been developed for Eclipta alba, a medicinally important plant, through transverse thin cell layer culture (tTCL). The transverse section of the nodal segment of field grown plants was used as tTCL explants for plant regeneration. Shoot multiplication from tTCL nodal explants was influenced by BAP and their interaction with Kin or NAA. MS medium containing 13.2 μM BAP and 4.6 μM Kin was most effective for shoot multiplication from tTCL nodal explants. Upon this medium, percent response for shoot proliferation was 100% with an average of 32.6 shoot buds per tTCL nodal explant. Regenerated shoots from tTCL nodal explants were rooted on the growth regulator free MS medium. The rooted plantlets were successfully acclimatized and established in soil with a survival frequency of 90-100%. Random amplified polymorphic DNA (RAPD) markers were used to evaluate the genetic fidelity of the micropropagated plants. RAPD profile analysis indicated that micropropagated plants were genetically similar to mother plant.     

Large scale in vitro propagation of Stevia rebaudiana (bert) for commercial application: Pharmaceutically important and antidiabetic medicinal herb

Stevia rebaudiana is a valuable medicinal plant species and it is being used for the treatment of diabetes. Currently, there is a high demand for raw material of this medicinal herb due to ever increasing diabetes disorder among the population. In order to meet the increased demand an efficient in vitro propagation of S. rebaudiana was established. Nodal explants collected from the field were cultured on MS basal medium fortified with different concentrations of BAP (0.5-3.0 mg/l) and KIN (0.5-3.0 mg/l) individually for shoot bud induction. In vitro derived nodal buds were cultured on MS medium supplemented with different concentrations (0.5-3.0 mg/l) of BAP and KIN for multiple shoot bud regeneration. In the second experiment, in vitro derived buds were placed on MS medium supplemented with different concentrations of BAP (0.5-3.0 mg/l) in combination with 0.5 mg/l IAA or IBA or NAA for shoot bud multiplication. The highest frequency (94.50%) of multiple shoot regeneration with maximum number of shoots (15.69 shoots/explant) was noticed on MS medium supplemented with 1.0 mg/l BAP. For large scale plant production, in vitro derived nodal bud explants were cultured on MS medium fortified with 1.0 mg/l BAP, in which about 123 shoots/explant were obtained after three subcultures on the same media composition. Elongated shoots (>2 cm) dissected out from the in vitro proliferated shoot clumps were cultured on half-strength MS medium containing different concentrations of NAA (0.1-0.5 mg/l) and/or MS medium fortified with various concentrations (0.5-2.0 mg/l) of auxins (NAA, IAA and IBA) for root induction. Highest frequency of rooting (96%) was noticed on half-strength MS medium augmented with 0.4 mg/l NAA. The rooted plantlets were successfully transferred into plastic cups containing sand and soil in the ratio of 1:2 and subsequently established in the greenhouse. The present in vitro propagation protocol would facilitate an alternative method for rapid and large-scale production of this important antidiabetic medicinal plant.     

Assessment of genetic stability in micropropagules of Jatropha curcas genotypes by RAPD and AFLP analysis

Jatropha curcas (Euphorbiaceae), a drought resistant non edible oil yielding plant, has acquired significant importance as an alternative renewable energy source. Low and inconsistent yields found in field plantations prompted for identification of high yielding clones and their large scale multiplication by vegetative propagation to obtain true to type plants. In the current investigation plantlets of J. curcas generated by axillary bud proliferation (micropropagation) using nodal segments obtained from selected high yielding genotypes were assessed for their genetic stability using Randomly Amplified Polymorphic DNA (RAPD) and Amplified Fragment Length Polymorphism (AFLP) analyses. For RAPD analysis, 21 out of 52 arbitrary decamer primers screened gave clear reproducible bands. In the micropropagated plantlets obtained from the 2nd sub-culture, 4 out of a total of 177 bands scored were polymorphic, but in the 8th and 16th sub-cultures (culture cycle) no polymorphisms were detected. AFLP analysis revealed 0.63%, 0% and 0% polymorphism in the 2nd, 8th and 16th generations, respectively. When different genotypes, viz. IC 56557 16, IC 56557 34 and IC 56557 13, were assessed by AFLP, 0%, 0.31% and 0.47% polymorphisms were found, respectively, indicating a difference in genetic stability among the different genotypes. To the best of our knowledge this is the first report on assessment of genetic stability of micropropagated plantlets in J. curcas and suggests that axillary shoot proliferation can safely be used as an efficient micropropagation method for mass propagation of J. curcas.     

Response of selectedSolanum species to virus eradication therapy

Thirty-fourSolanum genotypes infected with one or more potato viruses were evaluated in anin vitro virus eradication system combining heat therapy and the antiviral chemical ribavirin. This system was compared within vitro heat therapy or ribavirin treatment alone. The effect of expiant size on virus eradication following therapy was also evaluated. Infected plantlets were established in ribavirin lacking and amended medium; half of the plantlets in each medium were subjected to a 30-day heat treatment (35 C/31 C, 4-hr alternating periods), while the remaining plantlets were kept at room temperature (23 C). Following therapy, plantlets were tested quantitatively (OD at A₄₀₅) for the appropriate virus by enzyme linked immunosorbent assay (ELISA) and divided into 3 categories: low(< -0.05 OD), medium (> 0.05 to < 1.0 OD) and high (> -1.0 OD). Three plantlets were selected per group and further propagated as nodal cuttings or meristemtips. Regenerants which tested negative (< -0.05 OD) were transplanted to plug trays in a greenhouse and were retested after a 30-day grow-out period. Seventy-four and 91% of the genotypes yielded virus-free (VF) plants following propagation as nodal cuttings and meristem-tips, respectively. The combined therapies generated twice as many VF plants as thermotherapy alone and 5% and 15% more VF plants for nodal cutting and meristemtip derived plantlets, respectively, than for chemotherapy alone. Eleven of the 34 genotypes exhibited susceptibility to heat, but VF plants were obtained from survivors or by shortening the thermotherapy period. The efficiency of the system was enhanced by selecting plantlets for propagation which tested < -0.05 OD after treatment with 92%, 93%, 71%, and 100% of them remaining VF from potato viruses S, X, Y and leafroll, respectively. Twice as many VF plantlets were produced when treated plantlets were then propagated from meristem-tips than from nodal cuttings, but the rapid regeneration rate of plantlets from nodal cuttings makes it an attractive propagation method. Plantlet evaluation by ELISA after therapy to select plantlets with a high probability of producing VF plantlets and after further propagation to assure virus freedom are strongly recommended.     

Nursery Growth of Banana (Musa spp.) Plantlets Rooted on Auxin-free and Auxin-supplemented Media

Abstract

This paper describes the effects of auxin added to the culture medium on main and branch root formation of banana (Musa spp.) shoots and growth characters of the plantlet rooted on the medium with and without auxin. Banana shoots cultured in vitro on Murashige and Skoog medium supplemented with 2 μM 1-naphthylacetic acid (NAA), rooted earlier and also had more adventitious roots than those cultured on the medium without NAA. However, the adventitious roots formed on the medium without NAA showed more lateral branching. Plant height and number of leaves per plantlet in in vitro culture were not influenced by the addition of NAA but under nursery conditions, plantlets rooted without NAA showed better growth in terms of days to the appearance of new leaf, plant height and number of leaves per plant. This might be due to the presence of abundant lateral roots. Even though auxins are generally known to promote rooting, NAA inhibited the formation of lateral roots in Banana plants.     

Manipulation of microtubers for direct field utilization in seed production

A two-year field study was conducted to determine the effects of jasmonic acid (JA), light (duringin vitro explant production andin vitro tuberization phases), and dormancy-breaking treatment on performance of microtubers in the production of seed tubers (pre-elite) in five potato cultivars. Microtubers were produced under short day (8-h) conditions and in darkness, from stock plantlets pre-treated with JA and untreated, and on tuberization media with or without JA. Microtuber performance was compared to invitro plantlets transplanted directly to the field. Yields of tubers from microtubers were 30% to 40% of those from plantlets. Microtubers of cultivars Amisk and Russet Burbank produced the highest yields of pre-elite tubers. Atlantic microtubers performed poorly in the field. JA pre-treatment of stock plantlets, prior toin vitro tuberization, enhanced seeds tuber production from microtubers in Russet Burbank and lowered in Shepody. JA presence in media duringin vitro tuberization significantly lowered production of tubers while exposure to 8-h light resulted in microtubers performing significantly better in the field than microtubers produced in the dark. Dormancy release was the key factor influencing microtuber performance. Unlike greenhouse studies, gibberellic acid (GA₃) was more effective than Rindite. A further refinement of the production and handling methods is required before microtubers can be recommended for field production of seed tubers.     

High-efficiency regnerationin vitro from potato petioles with intact leaflets

The shoot/plantlet regenerationin vitro of seven potato (Solanum tuberosum L.) cultivars from petioles with intact leaflets was assessed using six treatment combinations-a basal medium with or without silver thiosul-phate (STS) or thidiazuron (TDZ) at two concentrations (2 or 0.5 mg/l) of the indoleacetic acid (IAA). The basal medium consisted of Murashige and Skoog (MS) salts and vitamins supplemented with 3 mg/1 6-benzylaminopurine, and 1 mg/1 gibberellic acid, 30 g/l sucrose, and 7.0 g/l PHYTOAGAR. Two full sets repeats and one partial set repeat of independent experiments were conducted and all produced similar results. Silver thiosulphate decreased the regeneration frequency and number of shoots per callus. No significant changes were observed with thidiazuron. Regeneration rates of (100% ) with up to 20 shoots/plantlets per callus were achieved at 2 mg/1 IAA with cultivars Désirée, Kennebec, Niska, and Lenape. These cultivars still showed high regeneration rates (87%–98% ) on media with 0.5 mg/1 IAA, and good regeneration rates were also achieved by the other three cultivars (48%, 94%, and 50% for Chieftain, Russet Burbank, and Shepody, respectively). Even with the single medium protocol (0.5% IAA without thiosulphate or thidiazuron), Désirée, Lenape, and Niska exhibited a regeneration rate of 98%. The use of petiole-with-leaflet explants could be ideal for the regeneration step of potato genetic transformation protocol because of their high regeneration efficiency and their small cut surface area forAgrobacterium elimination after co-incubation.     

Use of jasmonate for conditioning of potato plantlets and microtubers in greenhouse production of minitubers

A two-year study was conducted to determine the effects of (1) jasmonic acid (JA) pre-treatment, (2) JA supplement in culture media, (3) cultivar (Amisk, Atlantic, Russet Burbank, Shepody, and Umatilla Russet), (4) light (0 h, 8 h), and (5) dormancy breaking treatment (Rindite, gibberellic acid) on greenhouse production of minitubers from microtubers andin vitro plantlets. The microtubers were produced under short day (8 h) light conditions and in darkness, from stock plantlets pre-treated with JA and untreated, and on tuberization media with or without JA.In vitro plantlets (the industry choice in nuclear seed potato production) of all five cultivars performed well, meeting the standard criteria for greenhouse production of minitubers. Production of minitubers from microtuber-derived plants of cvs Amisk, Russet Burbank, and Umatilla Russet was similar to that of plantlet-derived plants with regard to number of minitubers. Yields (weight), however, were lower than those from plantlets. Microtuber responses to JA varied with cultivar. Amisk produced the highest number of minitubers per plot from microtubers derived from JA pre-treated plantlets. Jasmonic acid-pretreated microtubers also gave significantly more minitubers in Russet Burbank and Umatilla Russet than the microtubers from other treatments. Shepody did not benefit from JA treatments and JA pre-treated Atlantic microtubers performed poorly, producing significantly lower yields of minitubers than other cultivars. Independently of cultivar, microtubers produced under 8-h photoperiod gave significantly higher yields of minitubers than microtubers produced in the dark. Dormancy release was the key factor influencing microtuber performance. Rindite proved to be a much more effective dormancy breaking treatment than gibberellin. JA conditioning of stock plants prior to tuberization is being proposed as a treatment in production of microtubers for greenhouse production of minitubers.     

Multiple buds are an alternative target to genetic manipulation of kenaf (Hibiscus cannabinus L.)

Kenaf (Hibiscus cannabinus L.) is an annual fiber crop cultivated as an important source of cellulose and lignin. In the recent years, fibers have increased their economic importance as organic component in bio-composite materials. However, industry requires rheological improvements of these fibers. Genetic manipulation has been considered a feasible approach for fiber improvement; however, kenaf is considered a crop species difficult to manipulate. Here we propose meristematic cells from mature embryos as target for genetic modification driven by Agrobacterium tumefaciens. In vitro meristems proliferation and multiple shoots regeneration were evaluated by sowing kenaf mature seeds on medium containing three different concentration of thidiazuron, a substituted urea compound. The highest number of regenerated shoots was obtained from mature seeds germinated in presence of 10 μM thidiazuron after 14 days of culture. Interactions between two A. tumefaciens strains and two kenaf varieties were assessed. Transgene stable integration and its inheritance in T₁ generation were also verified, demonstrating that kenaf meristematic cells are an useful target for genetic manipulation by agroinfection.     

Distribution of apple stem grooving virus and apple chlorotic leaf spot virus in infected in vitro pear shoots

The distribution patterns of Apple stem grooving virus (ASGV) and Apple chlorotic leaf spot virus (ACLSV) in in vitro-cultured pear plants were investigated using in situ tissue-printing hybridization (TPH) and tissue blotting immunoassay (TBIA) to detect viral RNAs and coating proteins. Both ASGV and ACLSV showed high concentrations in the tip of the pear shoots and lower concentrations in the middle stem. The highest viral RNA titers were found in the phloem parenchyma of vascular bundles. Monitoring of viral RNA concentrations was conducted on infected in vitro-cultured pear plants during thermotherapy using TPH combined with X-ray film exposure in serial cross sections. No viral RNA of ACLSV or ASGV was detected in less than 2 mm and 0.5 mm long tips, respectively. The heat treatment was less effective to reduce virus titers in the bottom shoot. The obtained results would assist in the selection of tips with proper sizes from pear shoots pre- and post-thermotherapy for the production of virus-free pear plants by meristem culture.     

Multiplex detection ofPotato virus S, Potato virus X, andPotato virus Y by non-radioactive nucleic acid spot hybridization in potato tissue culture plantlets

Potato plantlets initiated into tissue culture must be tested for numerous viruses prior to propagation for seed potato production. Ideally, one plantlet is tested for all pathogens of concern and, if found pathogen-free, this plantlet is propagated for production of seed potatoes. Commercially available ELISA kits are generally used for the pathogen tests, but the commercial kits have some limitations. For example, the protocols differ for different viruses, so multiple extractions must be completed, increasing the time and expense of testing. This is a significant problem with tissue culture plantlets, for which there is limited material available to test and an ever-increasing number of pathogens that must be tested for, including viruses in the potyvirus, carlavirus, potexvirus, luteovirus, pomovirus, tobravirus, tospovirus, alfamovirus, and tymovirus groups. We have optimized a non-radioactive nucleic acid hybridization (NASH) assay for the simultaneous detection of carlavirusPotato virus S (PVS), potexvirusPotato virus X (PVX) and potyvirusPotato virus Y (PVY) in potato tissue culture plantlets. This assay requires a single extraction from a small portion of a tissue culture plantlet for the detection of viruses from three different families.     

丛生芽—蝴蝶兰无性快速繁殖的新途径

不经过愈伤组织直接诱导蝴蝶兰“丛生芽”是一种变异率低的快繁方法。本文着重研究了诱导“丛生芽”的两个关键环节,即“丛生芽”的增殖及其壮苗的培育。随着BA浓度的提高,“丛生芽”增殖率上升,BA浓度分别为1,5,10,20mg/L培养50天后增殖率分别为189％,307％,475％,523％,但10mg/L培育的苗比20mg/L的壮。添加椰子水可使“丛生芽”的增殖率提高近1倍,而且生势较好。适当增加培养室的光照并加入香蕉和土豆等有机物能促进根系生长,使蝴蝶兰苗更健壮。     

蜜糖文心兰的组培快繁技术

以文心兰盆栽品种‘蜜糖'的侧芽为实验材料,研究基本培养基、激素配比、pH值、蔗糖浓度和添加物等对原球茎增殖的影响,探讨文心兰的生根壮苗与炼苗移栽技术.结果表明:(1)文心兰侧芽茎尖在MS+6-BA 4.0mg/L+NAA 1.0mg,L的培养基上能形成原球茎;培养基的pH值为5.8时较有利于原球茎的增殖;最适宜原球茎增殖的培养基为:MS+6-BA 2.0 mg/L+NAA 0.2 mg/L+蔗糖30 g/L+10%香蕉泥.(2)原球茎在MS+6-BA 0.6 mg/L+NAA 0.1 mg,L+蔗糖30 g/L的培养基上能分化出芽,萌芽率可达83.4%;无根苗在1/2 MS+IAA 0.2 mg/L+10%香蕉泥+蔗糖30 g,L的培养基上能形成完整植株,培养35 d后的生根率为92.5%,且假鳞茎饱满,植株健壮,试管苗移栽在水苔上的成活率可达94.6%.