Types Of Culture Vessels Research Articles

ОПТИМИЗАЦИЯ СОСТАВА ПИТАТЕЛЬНОЙ СРЕДЫ И УСЛОВИЙ КУЛЬТИВИРОВАНИЯ ДЛЯ МИКРОРАЗМНОЖЕНИЯ IN VITRO THYMUS SERPYLLUM L. И THYMUS CAUCASICUS WILLD.

The study was conducted to optimize the cultivation conditions for the second stage of clonal micropropagation of Thymus caucasicus Willd. and Thymus serpullum L. Stem segments with one node (8…10 mm), obtained by microcutting of shoots, were cultured on 10 different Murashige and Skoog (MS) nutrient media containing 2% sucrose and 0.8% agar-agar, with the addition of kinetin, thidiazuron, benzylaminopurine (BAP), indoleacetic and gibberellic acids. Various culture vessels (jars, flasks, test tubes) were used for micropropagation. The duration of the cultivation cycle varied from 40 to 70 days. The highest reproduction coefficient of T. serpyllum was noted on the MS medium containing 1.0 mg/l BAP and was 6.7, while that of T. caucasicus was on the MS medium containing 1.0 mg/l kinetin (16.1). The highest efficiency of culturing both thyme species was achieved in jars, with the use of which the reproduction coefficient was 1.4…2.1 times higher than when grown in test tubes or flasks. It is advisable to cultivate the studied thyme species with a standard cycle of 40 days. The best combinations of various thyme reproduction factors contributed to the maximum manifestation of the morphogenetic potential in in vitro experiments. The greatest influence on the multiplication coefficient was exerted by the type of culture vessel, the interaction of the composition of the nutrient medium and the genotype, as well as the composition of the nutrient medium (the shares of the influence of factors ranged from 20.0% to 25.3%). The results of the studies served as the basis for the development of a protocol that can be used for accelerated micropropagation of T. caucasicus and T. serpullum.

Comparison of THP-1 Macrophages Viability in Different Types of Culture Vessel

The ox-LDL generated apoptotic bodies using THP-1 macrophage is a useful tool to study foam cell formation in atherosclerosis. However, the common problem is the cells in the negative control (i.e., absence of ox-LDL) undergo apoptosis. Therefore, the type of cell culture vessel was proposed to be the key factor contributing to cell apoptosis. The THP-1 cells were differentiated into M1 macrophages using 10 ng/μL PMA, 5 ng/μL LPS, and 20 ng/μL IFN-? while 5 ng/μL PMA, 20 ng/μL IL-4 and 20 ng/μL IL-13 were used to differentiate THP-1 into M2 macrophages. Two types of cell culture vessels (6-well plate and T25 flask) were used to culture the macrophages. The cells were subsequently stained using Annexin V-FITC and Propidium Iodide prior to flow cytometry analysis. Interestingly, both M1 and M2 macrophages cultured in the T25 flask resulted in a significantly higher percentage of cell viability compared to macrophages cultured in 6-well plate [M1: 84.15% ± 4.39 vs 8.02% ± 1.55, p < 0.0001; M2: 95.95% ± 1.74 vs 10.50% ± 0.05, p < 0.0001]. In summary, the type of culture vessel is a vital factor in determining cell viability attributed to the surface area and cell seeding density in different types of vessels.

The effect of different gelling agents as part of culture medium on the rate of cucumber (<i>Cucumis sativus</i> L.) unpollinated ovules gynogenic development

Relevance. The induction of gynogenic development of the culture of unpollinated ovules of Cucumis sativus L., as a part of solid nutrient media agar-agar or Phytagel™ are used as a gelling agent. The gelling agent determines the mobilization of substances in the composition of the nutrient medium and has various effects on the explants, which affects the quality of the resulting regenerates. However, there are no scientific works that explaines the effect of these gelling agents on the development of ovules and compare them with each other for C. sativus L. The aim: investigate the effect of various gelling agent in the nutrient medium on the induction of gynogenesis and the development of cucumber unpollinated ovules.Materials and methods. There are two promising collection specimens of cucumber №58 and №831 of the laboratory of cucurbits crop breeding and seed production of FSBSI FSVC were included into research. IMC nutrient medium (Induction Medium for Cucurbitaceae) with 30 g/l sucrose, 200 mg/l ampicillin, 0.2 mg/l thidiazuron (TDZ) was used for the induction of gynogenesis; agar-agar at a concentration of 7 g/l or Phytagel™ at a concentration of 3.5 g/l was used as a gel-forming agents. Ovules were isolated from ovaries in the phase of half-opened flower (FL-1) and fully opened flower (FL). Cultivation was carried out in plastic Petri dishes with a diameter of 60 mm with an air gap of 28.8 cm3 – "KS No. 1", and glass culture jars with an air gap of 140 cm3 – "KS No. 2".Results. On containing Phytagel™ or agar-agar nutrient medium, the area of ovules during 30 days of cultivation increases irregularly. Coefficients of ovule enlargement between gelling agents differed from 1.7 to 2.6 times depending on the cultivation time. The average growth rate of ovules on media with Phytagel™ was 0.08 mm2/day, while on media with agar-agar it was 0.02 mm2/day. Gelling agents type and cucumber phenotype are significant factors affecting the increase in area of entered into unpollinated cucumber ovules culture. Herewith the share of the gelling agent effect was 55.01%, and the share of genotype effect was 14.53%. The effect of flower development stage or culture vessel type has not found for both of genotypes. In the study, it was possible to achieve the induction of gynogenesis in 67% of the unpollinated ovules genotype №831 on nutrient medium with agar-agar.Conclusion. Ovules development were faster on a nutrient medium using Phytagel™ as a gelling agent than on agaragar. At the same time, the percentage of induced ovules was significally higher on nutrient medium with agar-agar for both phenotypes. Gelling agents type and cucumber phenotype were found as significant factors of the induction and the development of unpollinated ovules.

Correction to: Differential morphometric and micro-morpho-anatomical responses toward types of culture vessels used in micropropagation of Hemidesmus indicus (L.) R. Br.

Correction to: Differential morphometric and micro-morpho-anatomical responses toward types of culture vessels used in micropropagation of Hemidesmus indicus (L.) R. Br.

Differential morphometric and micro-morpho-anatomical responses toward types of culture vessels used in micropropagation of Hemidesmus indicus (L.) R. Br.

Differential morphometric and micro-morpho-anatomical responses toward types of culture vessels used in micropropagation of Hemidesmus indicus (L.) R. Br.

Microdissected Tissue vs Tissue Slices-A Comparative Study of Tumor Explant Models Cultured On-Chip and Off-Chip.

Simple SummaryCancer drugs have the lowest success rate of approval in drug development programs. In order to address this, predictive preclinical assays that correctly reflect the clinical efficacy of a drug represent an urgent need in both clinical oncology and pharmaceutical research. To address this need, multiple tumor models have been developed, including tumor explant culture platforms, which are the only models that preserve the integrity of the tumor tissue. However, these models have not been fully characterized and multiple variables exist between studies. We investigated the effect of tissue size and culture vessel type on the survival of tumor explants by comparing micro-dissected tumor tissue with corresponding tumor slices. Our results show that the model geometry and culture vessel affect proliferation, apoptosis, and hypoxia in tissue cultures, and must be considered in designing tumor explant culture platforms.Predicting patient responses to anticancer drugs is a major challenge both at the drug development stage and during cancer treatment. Tumor explant culture platforms (TECPs) preserve the native tissue architecture and are well-suited for drug response assays. However, tissue longevity in these models is relatively low. Several methodologies have been developed to address this issue, although no study has compared their efficacy in a controlled fashion. We investigated the effect of two variables in TECPs, specifically, the tissue size and culture vessel on tissue survival using micro-dissected tumor tissue (MDT) and tissue slices which were cultured in microfluidic chips and plastic well plates. Tumor models were produced from ovarian and prostate cancer cell line xenografts and were matched in terms of the specimen, total volume of tissue, and respective volume of medium in each culture system. We examined morphology, viability, and hypoxia in the various tumor models. Our observations suggest that the viability and proliferative capacity of MDTs were not affected during the time course of the experiments. In contrast, tissue slices had reduced proliferation and showed increased cell death and hypoxia under both culture conditions. Tissue slices cultured in microfluidic devices had a lower degree of hypoxia compared to those in 96-well plates. Globally, our results show that tissue slices have lower survival rates compared to MDTs due to inherent diffusion limitations, and that microfluidic devices may decrease hypoxia in tumor models.

Triaging of Culture Conditions for Enhanced Secondary Metabolite Diversity from Different Bacteria.

Over the past decade, the one strain many compounds (OSMAC) approach has been established for the activation of biosynthetic gene clusters (BGCs), which mainly encode the enzymes of secondary metabolite (SM) biosynthesis pathways. These BGCs were successfully activated by altering various culture conditions, such as aeration rate, temperature, and nutrient composition. Here, we determined the biosynthetic potential of 43 bacteria using the genome mining tool antiSMASH. Based on the number of BGCs, biological safety, availability of deposited cultures, and literature coverage, we selected five promising candidates: Bacillus amyloliquefaciens DSM7, Corallococcus coralloides DSM2259, Pyxidicoccus fallax HKI727, Rhodococcus jostii DSM44719, and Streptomyces griseochromogenes DSM40499. The bacteria were cultivated under a broad range of OSMAC conditions (nutrient-rich media, minimal media, nutrient-limited media, addition of organic solvents, addition of biotic additives, and type of culture vessel) to fully assess the biosynthetic potential. In particular, we investigated so far scarcely applied OSMAC conditions to enhance the diversity of SMs. We detected the four predicted compounds bacillibactin, desferrioxamine B, myxochelin A, and surfactin. In total, 590 novel mass features were detected in a broad range of investigated OSMAC conditions, which outnumber the predicted gene clusters for all investigated bacteria by far. Interestingly, we detected mass features of the bioactive compounds cyclo-(Tyr-Pro) and nocardamin in extracts of DSM7 and DSM2259. Both compounds were so far not reported for these strains, indicating that our broad OSMAC screening approach was successful. Remarkably, the infrequently applied OSMAC conditions in defined medium with and without nutrient limitation were demonstrated to be very effective for BGC activation and for SM discovery.

Photoautotrophic micropropagation system (PAM): a novel approach deserving increased uptake for commercial plant production

Most commercial plant tissue culture laboratories still use conventional micropropagation systems, requiring air-tight vessels and gelled medium supplemented with sugar. There is, however, a more efficient and economic system available, called “photoautotrophic micropropagation system” (PAM). Application of sugar-free medium and ventilated vessels are the key features of this system, which significantly improves plant physiological processes including photosynthesis and transpiration. The genetic basis for this has become more clear with a recent transcriptomic analysis of potato plantlets cultured on sugar-free medium showing the upregulation of more than 2000 genes, many of which are associated with photosynthesis efficiency and leaf cell development. The cultured plants from PAM exhibit improved vigour and health enabling a faster and smoother acclimatisation stage. Moreover, PAM is amenable to automation and scaling up by using large culture vessels/rooms. Here, we reviewed the recent studies on PAM and the issues/barriers to its commercialisation have also been discussed. Optimal culture conditions as well as different types of culture vessels are also explained.

A high throughput plant regeneration system from shoot stems of Sapium sebiferum Roxb., a potential multipurpose bioenergy tree

Sapium sebiferum Roxb. is an economically important multipurpose woody plant in terms of its biodiesel-producing, medicinal and ornamental values. In the present study, a high throughput in vitro regeneration system of S. sebiferum through direct shoot organogenesis from shoot stems was developed. The effects of plant growth regulators (PGRs), explant orientation, culture vessel type, explant type and explant source on adventitious shoot induction were investigated. Adventitious shoots were induced from cut ends of shoot stems with or without axillary buds when they were cultivated on the Murashige and Skoog (MS) medium fortified with 6-benzylaminopurine (6-BA). The highest rate of shoot induction (100 %) with mean number of shoot buds (21.4 ± 0.2) per explant was obtained when in vitro shoot stems without axillary buds were placed horizontally on the medium supplemented with 0.5 mg l−1 6-BA in glass petri dish. The induced shoot buds were transferred to MS medium supplemented with 0.5 mg l−1 6-BA and 0.1 mg l−1 gibberellic acid (GA3) for shoot proliferation and elongation. The elongated shoots were continuously propagated through shoot stem sectioning until used for rooting. For in vitro adventitious root induction, the elongated shoots were cultivated on the MS basal medium supplemented with different strengths of macronutrient, various concentrations of auxins and sucrose. The highest root induction (100 %) was achieved when the elongated shoots were cultured on 1/8 MS medium fortified with 2.0 % sucrose and 0.5 mg l-1 indole-3-butyric acid (IBA). For ex vitro rooting, 98.3 % shoots rooted when they were pretreated with IBA (1000 mg l-1) for 60 s. The plantlets rooted by both methods were successfully acclimatized and showed normal development with 91.4 % and 98.1 % survival rate, respectively. The genetic fidelity of the regenerants was confirmed by inter simple sequence repeat (ISSR) markers. The present in vitro regeneration protocol will play an important role in large-scale propagation, germplasm conservation as well as genetic improvement of this economically important multipurpose plant species.

Photomixotrophic growth response of sugarcane in vitro plantlets using different light intensities and culture vessel types

Sugarcane is a very important crop in tropical areas around the world. Optimizing the light intensity and culture vessel for sugarcane in vitro propagation can improve protocols for large-scale in vitro mass clonal propagation. The objective of this study was to evaluate biometric and anatomical characteristics of in vitro propagated sugarcane plantlets using different light intensities and culture vessel types. The study also aimed to stimulate desired photoautotrophic and/or photomixotrophic traits and to study correlations between survival and ex vitro vigor with in vitro data. Fluorescent lights at 70 μmol m−2 s−1 and light-emitting diodes (LEDs) at 120 and 200 μmol m−2 s−1 were used combined with different culture vessel types, including microboxes without a filter, microboxes with a filter, and baby food jars. Propagation and rooting growth were observed in all in vitro culture conditions. However, an increase in light intensity and change of culture vessel type provided improved results. When sugarcane plantlets were cultivated within microboxes with a filter under 120 and 200 μmol m−2 s−1, they showed improved growth, increased chlorophyll content, the lowest leaf yellowing percentage, an increase in bulliform cells and, consequently, increased leaf thickness under in vitro culture. After 60 d in greenhouse conditions, in vitro-derived plantlets under LEDs and microbox culture vessels showed the highest biometric values and high ex vitro survival.

Factors influencing multinucleated giant cell formation in vitro.

Macrophages fuse together to form multinucleated giant cells (MGC) in granulomas associated with various pathological conditions. Improved in vitro methods are required to better enable investigations of MGC biology and potential contribution to disease. There is a need for standardization of MGC quantification, purification of MGC populations, and characterization of how cell culture variables influence MGC formation. This study examined solutions to address these needs while providing context with other current and alternative methods. Primary mouse bone marrow-derived macrophages were treated with interleukin-4, a cytokine known to induce fusion into MGC. This model was used to systematically assess the influence of cell stimulant timing, cell seeding density, colony stimulating factors, and culture vessel type. Results indicated that MGC formation is greatly impacted by alterations in certain culture variables. An assessment of previously published research showed that these culture conditions varied widely between different laboratories, which may explain inconsistencies in the literature. A particularly novel and unexpected observation was that MGC formation appears to be greatly increased by silicone, which is a component of a chamber slide system commonly used for MGC studies. The most successful quantification method was fluorescent staining with semi-automated morphological evaluation. The most successful enrichment method was microfiltration. Overall, this study takes steps toward standardizing in vitro methods, enhancing replicability, and guiding investigators attempting to culture, quantify, and enrich MGC.

Production of renewable biohydrogen by Rhodobacter sphaeroides S10: A comparison of photobioreactors

Abstract Photosynthetic bacterium Rhodobacter sphaeroides S10 was grown photoheterotrophically to produce hydrogen in three types of culture vessels having very different surface-to-volume ratios (S). The aim was to investigate the effect of the culture system geometry (low-aspect ratio cylindrical geometry, a rectangular or flat bottle geometry, and a tubular loop) on growth and hydrogen production as the culture vessel geometry affects the average internal irradiance. A mixed carbon substrate produced by hydrolysis of oil palm empty fruit bunch fibers was used to grow the bacterium and produce hydrogen. Internal average irradiance was shown to affect growth and hydrogen production. A tubular photobioreactor with a high surface area to culture volume ratio (S = 181.7 m−1) proved to be the best culture system for producing hydrogen at a high rate. In contrast, the highest value of the maximum specific growth rate occurred in the relatively poorly lit culture of the cylindrical vessel with a comparatively low surface-to-volume ratio (S = 52.3 m−1). The result suggests that irradiance regimen is a key factor controlling the switch from biomass production to hydrogen production.

Large-Scale Mesenchymal Stem/Stromal Cell Expansion: A Visualization Tool for Bioprocess Comparison

Large-scale and cost-effective cell expansion processes are a prerequisite for the clinical and commercial translation of cell-based therapies. A large variety of cell expansion processes are described in literature, utilizing different cell types, culture vessels, and medium formulations. Consequently there are no straightforward means for the comparison or benchmarking of these processes in terms of efficiency, scale, or costs. The purpose of this study was to systematically review the available mesenchymal stromal cell (MSC) expansion literature and develop an interactive visualization tool for comparing the expansion processes. By using this computational tool, process data could be concentrated, standardized, and analyzed to facilitate a more general understanding of the parameters that define a cell culture process, and in the future allow rational selection or design of these bioprocesses. Additionally, a set of bioprocess metrics were defined that assured the comparability between different processes. Currently, the literature-based data repository holds 73 individual cell expansion processes on seven different types of human MSCs in five different types of culture vessels. The visualization tool allowed benchmarking of these processes against each other, serving as a reference point for cell expansion process efficiency.

Oxygen transfer rates in shaken culture vessels from Fernbach flasks to microtiter plates.

By a sulfite oxidation method, oxygen transfer rates (OTRs) were determined in 11 types of culture vessels from 2.8-L Fernbach (FB) flasks to 96-, 48-, and 24-well square deepwell microtiter plates (MTPs). OTRs ranged from 140 mM/h in 250-mL Ultrayield™ flasks shaken at 300 rpm with a 50 mm diameter shaker throw to 5 mM/h in unbaffled FBs shaken at 200 rpm with a 25 mm throw. Baffles in FBs increased OTRs 6-12-fold under various shaking conditions, and up to five-fold in 250-mL flasks, depending on the type of baffles. Corner-baffling was superior to bottom-baffling in glass, 250-mL flasks. In MTPs, OTRs increased with increasing well size and decreasing fill volume. At 50 mm throw and 300 rpm, 24-well MTPs had OTRs comparable to corner-baffled, 250-mL flasks (∼100 mM/h). The OTRs in unbaffled flasks were relatively insensitive to shaking conditions, increasing less than two-fold between the most modest and the most vigorous conditions. There was no consistency across vessels as to whether the alternate incubation conditions of 70 mm throw and 250 rpm produced higher OTRs than the 50 mm throw and 300 rpm regimen. No increase in OTR was seen in any MTP when the cover hole diameter was increased beyond 4.5 mm. OTRs decreased as viscosity increased, falling smoothly in unbaffled flasks and 24-well MTPs, but 48-well and 96-well MTPs showed precipitous OTR drops as viscosity increased. Matching the OTRs of screening vessels to the oxygen uptake rates of microbial cultures can greatly reduce the number of false positive strains that are forwarded from microbial screens. Biotechnol. Bioeng. 2016;113: 1729-1735. © 2016 Wiley Periodicals, Inc.

Callus cultures of Harpagophytum procumbens (Burch.) DC. ex Meisn.; production of secondary metabolites and antioxidant activity

Three cotyledon-derived callus lines of Harpagophytum procumbens were established on agar-solidified Schenk and Hildebrandt (SH) medium supplemented with 0.2mgL−1 α-naphthaleneacetic acid (NAA) and 1mgL−1 6-benzylaminopurine (BAP) (CNB line), 0.5mgL−1 picloram (CP0.5 line) or 2mgL−1 picloram (CP2 line). They were maintained in three different culture vessels: culture tubes, Erlenmeyer flasks and Magenta vessels. Hormonal treatment and type of culture vessel influenced callus growth and morphology. The highest biomass (64- to 130-fold increase in fresh and dry weights within 4weeks) was achieved in Erlenmeyer flasks. The contents of major phenylethanoid and iridoid glycosides in the calli were determined by high performance liquid chromatography (HPLC). Harpagoside, harpagide, verbascoside and isoverbascoside were identified and the ability to produce these bioactive compounds sustained for over 3years. H. procumbens calli were also analyzed by colorimetric methods for total contents of phenolics, flavonoids and anthocyanins. The extracts of CNB callus had the highest antiradical activity against DPPH and ABTS and capacity to reduce metal ions (Ferric Reducing Antioxidant Power—FRAP). The same extracts were also characterized by the highest total content of phenolics and flavonoids.

Secondary multiplication of somatic embryos in banana (Musa spp. AAA) in semisolid medium: effect of the culture vessel type and sterilization method

The objective of this work was to evaluate the influence of the type of culture vessel, and sterilization method on secondary multiplication of somatic embryos of the banana cultivar Grande naine (AAA) in semisolid culture medium. From 200 µl of embryogenic cell aggregates, somatic embryos in the globular stage were formed, which were used in the experiments to compare the types of culture vessel (glass and plastic) and the form of sterilization – humid heat (autoclave) and chemical (Vitrofural®). The evaluations of the number of somatic embryos that were multiplied were done at 15 and 20 days of culture. The results obtained with respect to the multiplication phase were highly promising, 40.25 and 80.15 ± 5.0 somatic embryos at 15 and 20 days of culture in glass vessel with plastic cover and using the autoclave as the sterilization method. The results presented in this work open the door for the use of this phase in the mass propagation protocol of this crop via somatic embryogenesis.

Eficiência fotossintética e crescimento de genótipos de abacaxizeiro cultivados in vitro em diferentes qualidades de luz, tipos de frasco de cultivo e concentrações de sacarose

Foram otimizados os protocolos de micropropagação das cultivares de abacaxizeiro 'Vitória' e 'IAC Fantástico', bem como as respostas fotossintéticas e de crescimento destes genótipos à alteração do ambiente de cultivo in vitro. Para as duas cultivares, os tratamentos foram dispostos em DIC, com seis repetições e cinco plantas por repetição, em um esquema de parcelas subsubdivididas, constituídas de qualidade de luz (branca e vermelha), tipo de frasco de cultivo (fechado e ventilado) e concentração de sacarose no meio de cultivo (15 e 30 g L-1). A avaliação foi feita após 40 dias de cultivo in vitro. Nas condições deste estudo, não houve assimilação fotossintética do carbono. Essa não assimilação foi associada ao comprometimento bioquímico e sem comprometimento na eficiência fotoquímica. A presença da sacarose pode ser considerada o fator responsável pela não assimilação do CO2. Em comparação à cv. IAC Fantástico, a cv. Vitória apresentou maior crescimento devido à maior absorção de carbono via sacarose adicionada ao meio de cultivo.

Insect cell culture in reagent bottles

Growing insect cells with high air space in culture vessel is common from the early development of suspension cell culture. We believed and followed it with the hope that it allows sufficient air for optimal cell growth. However, we missed to identify how much air exactly cells need for its growth and multiplication. Here we present the innovative method that changed the way we run insect cell culture. The method is easy to adapt, cost-effective and useful for both academic and industrial research labs. We believe this method will revolutionize the way we run insect cell culture by increasing throughput in a cost-effective way.In our study we identified:•Insect cells need to be in suspension; air space in culture vessel and type of culture vessel is of less importance. Shaking condition that introduces small air bubbles and maintains it in suspension for longer time provides better oxygen transfer in liquid. For this, high-fill volume in combination with speed and shaking diameter are important.•Commercially available insect cells are not fragile as original isolates. These cells can easily withstand higher shaking speed.•Growth condition in particular lab set-up needs to be optimized. The condition used in one lab may not be optimum for another lab due to different incubators from different vendors.

Influence of Various Types of Culture Vessels upon the In Vitro Multiplication of Highbush Blueberry (Vaccinium corymbosum)

Our paper presents aspects regarding the influence of culture vessels upon multiplication rate in the highbush blueberry ( Vaccinium corymbosum ) cultivar `Blue Crop`. Modified Woody Plant Medium (WPM) with 5 mg/l 2-Isopentenyladenine (2-Ip) and 20 mg/l ascorbic acid was used as culture medium. The following types of culture vessels were tested: Magenta GA7, 720 ml jars with metal caps vented with sponge filters, 720 ml jars with polycarbonate caps without venting, 720 ml jars with vented polycarbonate caps equipped with filters made of water-resistant bandaids, 320 ml jam jars with polycarbonate caps without venting and Eco 2 Box vessels with vented caps. The best growth and highest multiplication rates were obtained in the 720 ml jars with metal caps vented with sponge filters and the shoots were vigorous, with intense green color.

Fast growing aspens in the development of a plant micropropagation system based on plant-produced ethylene action

Representatives of the genus Populus (poplars), such as Populus tremula L. (European aspen) and its fast-growing hybrids, are recognized as being among the most suitable tree species for short rotation coppicing in Northern Europe. Several technologies have been developed for fast propagation of selected aspen genotypes, including laboratory (in vitro) micropropagation, which is usually based on the action of exogenous plant hormones. Seeking to minimize the use of the latter, the present study was designed to test if the conditions suitable for increased accumulation of plant-produced gas, including the gaseous plant hormone ethylene, inside a culture vessel could contribute to commercially desirable changes in aspen development. Shoot cultures of several European and hybrid (Populus tremuloides Michx. × P. tremula) aspen genotypes were studied using two different types of culture vessels: tightly sealed Petri dishes (15 × 54 mm) designed to provide restricted gas exchange (RGE) conditions, and capped (but not sealed) test tubes (150 × 18 mm) providing control conditions. Under RGE conditions, not only the positive impact of the ethylene precursors 1-aminocyclopropane-1-carboxylic-acid (ACC) and ethephon on shoot proliferation was demonstrated but also a several-fold increase, compared to the control conditions, in the mean shoot number per explant was recorded even on the hormone-free nutrient medium. Moreover, the shoots developed under RGE conditions were distinguished by superior rooting ability in the subsequent culture. These results suggest that a plant micropropagation system based on the action of plant-produced ethylene rather than of exogenous hormones is possible.