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In comparison with plantlets produced by the conventional micropropagation system using small vessels with sugar-containing medium, plantlets produced by the photoautotrophic micropropagation system using large vessels with sugar-free medium resulted in better growth, lower percent loss due to contamination, higher quality, higher percent survival ex vitro, and lower production costs. Therefore, the photoautotrophic micropropagation system has advantages over the conventional micropropagation system for commercial production of Calla lily and China fir plantlets with respect to production costs and sales price. This system should be useful for commercial production of micropropagated plantlets of other plant species. [ABSTRACT FROM AUTHOR]

DO is one of the environmental factors that strongly affect the development of somatic embryos in the suspension. Regulating the oxygen concentrations in the headspace of flasks, DO could be controlled without changing agitation conditions. Development of late stage embryos (large embryos) to the next stage was repressed by low DO level, while development of early stage embryos (small embryos) to the next stage was little affected. Utilizing this fact, the ratio of torpedo-stage embryos to the total embryos could be remarkably enhanced by dynamically controlling DO based on the non-invasive monitoring of the suspension. [ABSTRACT FROM AUTHOR]

Aeration in a tissue culture vessel can involve two different major processes. Firstly, bulk flow, humidity-induced and venturi-induced convective flows of air and diffusion of gas molecules. These processes may not be entirely unconnected and commonly can be termed as ‘natural aeration' or ‘natural ventilation'. Secondly, the ‘forced aeration' or ‘forced ventilation' where outer air are delivered to plant tissues by an external force. The demand of aeration in a tissue culture vessel can be accomplished by providing either or both of the above processes and thus tissue culture vessel should be designed more efficiently to maximize these processes. [ABSTRACT FROM AUTHOR]

Developing a system for producing high quality transplants at low costs is an important research subjects in the 21st century for resource saving, environmental conservation and biomass production. It can be concluded that quality and productivity of transplants are definitely higher and the growth period of transplants can be shortened by 30% or over when produced in the closed system using lamps than in the greenhouse using sunlight. The closed system is energy and material efficient especially with respect to the amounts of water required for irrigation and energy required for cooling in summer and for heating in winter. In addition, the closed system is an environmentally friendly system for plant production in the sense that it does not release polluted water that contains fertilizers to the outside and that it seldom requires pesticide and fungicide. Initial and operation costs of the closed system per annual production of transplants can be lower than or comparable to those of the greenhouse, and the closed system was first commercialized in 2002 in Japan, and has been used at 23 locations in 2004 in Japan. It is expected that the closed system is introduced in other Asian countries in 2005. [ABSTRACT FROM AUTHOR]

Micropropagation is still an industry in its infancy; costs are too high to compete in the marketplace effectively and consequently, the volumes necessary to make full use of advanced automation technologies are often lacking. If automation can be developed which decreases the direct cost per plantlet, by 50%, i.e., from US$ 0.35 to US$ 0.17, then certain markets will open up and volumes of plantlets sold will increase. Likewise, if flexibility and software advances permit users to modify robotic production lines in house, then greater numbers of varieties and species can be run through a single line, allowing more compatibility with the existing framework of micropropagation laboratories and their product mixes and annual fluctuations. Photoautotrophic culture systems offer significant hope for the future. As production volumes from biofermentation and other large scale handling systems become increasingly reliable, the industry will gain a higher degree of credibility in the eyes of large volume plant producers and additional inroads into markets with stringent requirements for delivery times and volumes can be made. Historical emphasis of micropropagation research has been on multiplication rates; however, these are not, in fact, the primary cost controlling factors. Once a minimum increase of 3.5-4 fold per subculture has been established, operator daily productivity contributes far more to the final cost; consequently, optimization of the operator throughput rates can yield significant benefits. Full automation and mechanization research needs to focus on dropping the price by nearly an order of magnitude, while establishing reliability and throughput quality, in order to drive the micropropagation industry to its next level. [ABSTRACT FROM AUTHOR]

For plant cell and tissue cultures, disposable bioreactors such as the Wave provide an efficient alternative to standard glass or steel bioreactors. Its application in process development as well as in small and middle volume commercial production processes can increase process safety and reduce time as well as process costs. For example, time-intensive cleaning and sterilisation procedures as well as intermediate steps for inoculum production can be omitted. Biomass as well as secondary metabolite production in Wave bioreactors is comparable or even higher than in traditional laboratory reactors. This is a consequence of optimum hydrodynamic characteristics for hairy roots, suspension cultures and embryogenic cultures. High shear stress can be countered by high filling volume, minimum rocking rates and angles. Because of these characteristics and, in addition, its scale-up capability, the Wave has enormous potential for efficient commercial production processes based on plant cells. We expect this potential to be verified in the near future. [ABSTRACT FROM AUTHOR]

The principles of oxygen mass transfer are presented to provide a qualitative understanding of the culture conditions where oxygen transport limitations can be observed. The context of the discussion is the applications of these principles to plant tissue culture propagation vessels and bioreactors. An experimental system which effectively uses an inhibitory protein driven by alcohol-inducible promoter is used as a qualitative probe of oxygen deprivation in the germinating seeds. Oxygen limitation is correctly predicted in this system even when the consumption rates of the seeds are extremely small as compared to the gas-liquid oxygen transfer rates. It is shown that the solid-liquid boundary layer is far more constraining for the delivery of oxygen. Use of oxygen enrichment of the gas phase overcomes this mass transfer limitation by increasing the driving force for transport in the bulk liquid phase. These principles of oxygen mass transfer can be adapted (both qualitatively and quantitatively) to many other aspects of oxygen-limited growth of plant tissues in culture. [ABSTRACT FROM AUTHOR]

Three-dimensional volumetric optimization in full immersion bioreactors is theoretically the most efficient way to grow plant cells. As the organism develops polarity, aerated shoots fixed in gaseous phase become more important to plant quality. Optimization of two dimensional growth surfaces for nutrient exchange, with an adequate aerial environment is necessary for micropropagation of shoots and plants of most species. Latter stages of somatic embryo conversion may similarly benefit from these approaches. If a system is to be readily used, it must conform to the human environment - simple, economic and robust. In this current iteration, the bioreactor has been simplified to a vessel that is placed on the shelf without mechanical linkages to pumps and motors. Unit size for plant-handling was dictated by the technician. Managers realize a scale-up factor that allows more active monitoring of process. Reasonably sized factorial experiments may rapidly determine optimization of genotype, PGR or nutrient-use scenarios. Values added to the young plant by enhanced transfer of nutrients can be delivered in the market competitively with plants produced on agar. [ABSTRACT FROM AUTHOR]

Image analysis has potential to provide simple, non-destructive, and objective quality evaluation of cultured cells for plant cell suspension culture. As compared with microscopic images, macroscopic images are more easily acquired without sampling, showing the potential for non-destructive evaluation. The visual texture of a macroscopic image of a cell suspension can be an indicator of cultured cell quality. The texture analysis of the macroscopic image was used for evaluation of embryogenic potential in cell suspension cultures. Texture analysis techniques are expected to contribute to maintenance of cell quality in plant cell suspension culture. Texture analysis is now used extensively for biological objects in various areas and novel methods have been reported. These technologies are expected to be transferred to plant tissue culture area. [ABSTRACT FROM AUTHOR]

Non-destructive measurements of photosynthetic properties of plants in culture vessels are useful for understanding relationships between culture conditions and photosynthetic capacity, offering data on changes in physiological state of the plants during culturing without disturbing the in vitro microenvironment. Chlorophyll fluorescence has potential for non-destructive evaluation of leaf photosynthetic properties because the measurement can be conducted based on photometry. Parameters derived from chlorophyll fluorescence measurements relate to the functioning of PSII, including the maximum quantum yield. Image analysis yielding these parameters is promising for non-destructive evaluation of photosynthetic capacity of micropropagated plants. [ABSTRACT FROM AUTHOR]