Changhoo Chun

Transplant Production in the 21st Century

Preface. 1: Closed transplant production systems. Necessity and concept of the closed transplant production system T. Kozai, et al. Closed transplant production system at Chiba University C. Chun, T. Kozai. Electric energy, water and carbon dioxide utilization efficiencies of a closed-type transplant production system K. Ohyama, et al. Microprecision irrigation system for transplant production H. Murase. Design concepts of computerized support systems for large-scale transplant production T. Hoshi, et al. 2: Technology in transplant production. Modeling, measurement and environmental control for transplant production. Modeling and simulation in transplant production under controlled environment C. Kubota. Object-oriented analysis and modeling of closed plant production systems D.H. Fleisher, K.C. Ting. Estimating cuticle resistance of seedling shoot tips based on the Penman-Monteith model H. Shimizu, R.D. Heins. Measurement of pH in guard cells using a confocal laser scanning microscope M. Yabusaki, et al. Does electrolyzed-reduced water protect plants from photoinhibition? K. Iwabuchi, et al. Environmental control for improved plant quality within controlled environment plant production systems S.T. Kania, G.A. Ciacomelli. Environmental engineering for transplant production C. Kirdmanee, K. Mosaleeyanon. Effects of air current on transpiration and net photosynthetic rates of plants in a closed plant production system Y. Kitaya, et al. Effects of air temperature, relative humidity and photosynthetic photon flux on the evapotranspiration rate of grafted seedlings under artificial lighting Y.H. Kim. Growth of tomato (Lycopersicon esculentum Mill.) plus transplants in a closed system at relatively highair current speeds -- A preliminary study W. Chintakovid, T. Kozai. Advances and current limitations of plug transplant technology in Korea B.R. Jeong. Lighting strategies for transplant production. A review on artificial lighting of tissue cultures and transplants W. Fang, R.C. Jao. Light emitting diodes (LEDs) as a radiation source for micropropagation of strawberry D.T. Nhut, et al. Application of red laser diode as a light source for plant production A. Yamazaki, et al. Effective vegetable transplant production programs for closed-type systems under different lighting regimes T. Maruo, et al. Photoautotrophic micropropagation in a natural light environment J. Adelberg, et al. High-quality transplant production. Production of value-added transplants in closed systems with artificial lighting H.-H. Kim, T. Kozai. High quality plug-transplants produced in a closed system enables pot-transplant production of pansy in the summer Y. Omura, et al. Yield and growth of sweetpotato using plug transplants as affected by their ages and planting depths A.F.M. Saiful Islam, et al. Yield and growth of sweetpotato using plug transplants as affected by cell volume of plug tray and type of cutting D. He, et al. Production of medical plant species in sterile, controlled environments S.J. Murch, et al. Effect of air temperature on tipburn incidence of butterhead and leaf lettuce in a plant factory K.Y. Choi, et al. Evaluation of lettuce cultivars suitable for closed plant production system M. Ishii, et al. Root growth subsequent to transplanting in plug-grown cabbage seedlings S. Yoshida. Effective storage conditions for subsequent growth enhancement of Ficus carica L. cuttings M. Takagaki, et al. 3: Biotechnology for tra

Necessity and Concept of the Closed Transplant Production System

We are requested to develop a concept, a methodology and an industry to solve the global issues on environmental pollution and shortages of food, feed, phytomass (plant biomass) and natural resources including fossil fuels and usable water. These issues are considered to become more and more serious on a larger scale in the forthcoming decades. In order to solve those issues in the 21st Century, billions of plants are required every year not only for food, feed and environment conservation, but also for alternative raw materials to produce energy, bio-degradable plastics and many other industrial products. By using plant-derived products, we can minimize the environmental pollution and the use of fossil fuels and atomic power. Then, we need billions of quality transplants (small plants) every year to be grown in the fields with maximum use of solar energy and minimum use of resources under harsh environmental conditions. These quality transplants can be produced only under carefully controlled environments. Bioengineering is expected to provide a useful concept and a methodology to develop the bioindustry for solving the above global issues substantially. In bioengineering, the global and local flows of energy, mass (or materials) and information are analyzed with special attention to the organic and inorganic metabolisms of plants, animals including humans and microorganisms. Concept of ‘closed-type or closed production systems’ is essential to develop a production system with minimum use of resources and with minimum environmental pollution. This concept can be applied to develop a closed-type transplant production system with artificial lighting for producing billions of quality transplants with minimum use of resources and with minimum environmental pollution. Research and development of the closed transplant production systems will create a new field of bioengineering and bioindustry.

Closed Transplant Production System at Chiba University

A closed system for transplant production was developed at the Matsudo campus of Chiba University, in order to study biological and engineering aspects of transplant production in closed systems and to test the feasibility of closed systems for production of transplants. In this system, virus-free transplants of sweetpotato (Ipomoea batatas (L.) Lam.) are vegetatively propagated and produced under sterilized conditions. Many new concepts and technologies are applied to this system to achieve the goal: to produce high-quality transplants at minimum usage of resources, and as scheduled. In the present paper, these concepts and technologies are introduced. A few examples of studies related to transplant production in closed systems using this facility are also described.

The effects of plant growth regulators, activated charcoal, and AgNO3 on microspore derived embryo formation in broccoli (Brassica oleracea L. var. italica)

Embryos derived from isolated microspore culture are of great importance for producing homozygous plants for breeding. Microspore culture can reduce time and laborious effort in the breeding of Brassica plants. Microspore derived embryos (MDE) formation in broccoli (Brassica oleracea L. var. italica Plenck) was studied with different plant growth regulators (PGRs), activated charcoal, and silver nitrate (AgNO3) to determine the optimal chemical conditions in the microspore culture. A 6-benzylaminopurine (BA) concentration of 0.05 mg L−1 resulted in increased MDE formation compared to those at other BA concentrations. Compared to the 0.05 mg L−1 BA concentration, fewer MDEs were formed in BA concentrations exceeding 0.1 mg L−1, similar to those cultured on medium without BA. However, 0.5× Nitsch & Nitsch (NLN) liquid medium supplemented with 0.05 mg L−1 napthalene acetic acid (NAA) and BA was more effective in inducing MDE formation than was BA alone. The higher MDE formation rate was observed in 0.5× NLN liquid culture medium containing 0.05 mg L−1 NAA and 0.01 mg L−1 BA. The MDE yield was significantly higher in all concentrations when activated charcoal was added to the microspore culture media. The optimal concentration of activated charcoal was 1.0 mg per petri dish, and the optimum AgNO3 concentration was 0.1 mg L−1, which induced MDE formation to 26.2 embryos, compared to 11.6 embryos without AgNO3.

Changes in physicochemical characteristics during fruit development in June-bearing strawberry cultivars

Changes in physicochemical characteristics were investigated during fruit development in ‘Maehyang’, ‘Seolhyang’, ‘Keumhyang’, ‘Akihime’, and ‘Red Pearl’ strawberries. Fresh weights and color parameters of strawberry fruits changed significantly during the fruit development in all cultivars. Fruit shapes of ‘Maehyang’ and ‘Akihime’ were conical, with an index of length to width being 1.5 and that of ‘Seolhyang’, ‘Keumhyang’, and ‘Red Pearl’ were cordate, the index being 1.3. Firmness decreased as the fruit developed in all cultivars. Contents of sugars, organic acids, ascorbic acid, and anthocyanin increased as the fruits developed while the ellagic acid content decreased. Sugars, ascorbic acid, and anthocyanin contents of ‘Maehyang’, ‘Seolhyang’, and ‘Keumhyang’ were higher than those of ‘Akihime’ and ‘Red Pearl’. Results indicate that newly-bred Korean strawberry cultivars containing high levels of bioactive compounds were superior to major Japanese cultivars that have been broadly cultivated in East Asian countries.

Comparative anatomy of embryogenic and non-embryogenic calli frompimpinella brachycarpa

Anatomical differences between embryogenic and non-embryogenic calli ofPimpinella brachycarpa were investigated by light microscopy and electron microscopy. Initial callus tissue emerged from expiants after 14 d of culturing. The embryogenie calli (EC) were firm, rather opaque, and light yellow in color. The cells usually formed small, compact clusters. Nonembryogenic calli (NEC), however, were friable, semitransparent, and yellow or gray. These formed relatively larger and loosely held clusters. Scanning electron microscopy showed that EC were composed of individual compact and spherical cells that were rather regular in size and approximately 20 µm long. All were tightly held together and appeared to organize globular embryos. In contrast, the NEC comprised elongated and loosely held cells that were approximately 50 µm long. Tubular and u-shaped NEC cells protruded irregularly, and were of varying heights along the cell aggregates. Transmission electron microscopy of the EC revealed typical eukaryotic cytoplasmic components, including nuclei, mitochondria, and vacuoles in the cytoplasm enclosed by an electron-transparent cell wall. Based on the numerous ribosomes within the cytoplasm, these cells appeared to be well-organized and metabolically active. The NEC cells were much larger and more highly vacuolated than those of the EC. In ultrathin sections, the former seemed to be almost devoid of other cellular contents except for plastids and nuclei. Furthermore, EC and NEC showed different regeneration capacities in their somatic embryo formation. Most EC produced hyperhydric somatic embryos, followed by normal somatic embryos; whereas only a few shooted or rooted somatic embryos arose from the NEC.

Effects of light intensity and relative humidity on photosynthesis, growth and graft-take of grafted cucumber seedlings during healing and acclimatization

Healing and acclimatization are key processes for the survival of grafted plants. This study evaluated the influence of light intensity (photosynthetic photon flux, PPF) and relative humidity during the healing and acclimatization period on the photosynthetic characteristics, graft-take, and growth of grafted cucumber (Cucumis sativus L.) seedlings, using a system for the continuous measurement of the CO2 exchange rate, in order to establish optimum environmental conditions for the healing and acclimatization of grafted cucumbers seedlings. Cucumbers (Cucumis sativus L. cv. Joeun Baekdadaki) were grafted onto rootstocks (Cucurbita maxima D. × C. moshata D. cv. New Shintozwa). Six combinations of two levels of relative humidity (95 and 90%) and three levels (0, 142, and 237 μmol·m−2·s−1) of light intensity were set up during healing and acclimatization. Increasing light intensity significantly increased CO2 exchange rates during healing and acclimatization. At 95 and 90% relative humidity, the CO2 exchange rates at 237 μmol·m−2·s−1 light intensity were 1.5 and 1.8 times higher than those at 142 μmol·m−2·s−1 light intensity, respectively. The light intensity during healing and acclimatization also affected the amount and distribution of chloroplasts in scion cotyledon. The amount of chloroplasts increased with the increase of PPF during healing and acclimatization, which covered most of cell wall with little open space left, compared with that of dark condition. As PPF increased, the shoot length, ratio of shoot to root, and specific leaf area decreased but the hypocotyl diameter, leaf area, dry weight, and percent dry matter increased. On the other hand, the relative humidity ranging from 90 to 95% did not significantly affect the CO2 exchange rates during healing, acclimatization, and growth of grafted cucumber seedlings. As a result, PPF during healing and acclimatization affected the growth and quality of grafted cucumber seedlings. This showed that higher PPF condition may improve the growth and quality of grafted cucumber seedlings.

Microspore derived embryo formation and doubled haploid plant production in broccoli ( Brassica oleracea L. var italica ) according to nutritional and environmental conditions

In cell culture, the maintenance of proper growing conditions is a key approach for improving the formation of embryos, and is useful in the production of doubled haploid (DH) plants. Optimal nutritional and environmental conditions for the microspore culture of Brassica oleracea L. var italica were determined in order to reduce time and effort in breeding. The optimal conditions for microspore embryo formation differed depending on genotype. Microspore-derived embryos (MDE) formation was influenced by the strength of the NLN medium, the microelement and sugar concentration, and the heat shock temperature and period. The 0.5XNLN liquid medium was the most favorable for MDE formation. The most efficient formation of MDE was observed in the 0.5X NLN liquid medium, without the addition of microelements. When 13 or 15% sucrose was added to the 0.5X NLN liquid medium, the amount of normal MDE formation increased. The optimum heat shock temperature and period for MDE formation was 32.5°C and 24 h, respectively. A polyploidy test indicated that 30% of the microspore derived plants were diploid throughout the embryogenesis process.

Root-zone cooling affects growth and development of paprika transplants grown in rockwool cubes

The possibility of improving the efficiency of transplant production during a summer season was studied by applying partial cooling of the root-zone during the cultivation of paprika transplants in a greenhouse. Paprika seedlings produced in a closed transplant production system were transferred to rockwool cubes, and cool-water circulation systems using plastic and stainless pipes were tested in a greenhouse during a summer season. The root-zone temperature of rockwool cubes and growth and development of paprika transplants as affected by root-zone cooling were investigated. When plastic pipes were used, the cooling efficacy by circulation of cool water (17°C) was the greatest and the temperature of rockwool cubes decreased by 3.6°C during the day time on a sunny day. Partial cooling of the root-zone enhanced root growth and increased number of flowers as compared with the transplants grown on uncooled rockwool cubes. The results indicate that partial cooling of the root-zone can alleviate damages to transplants commonly caused under high air temperature conditions, which could efficiently improve the paprika transplant production efficiency in greenhouses during the summer season.

A Closed-Type Transplant Production System

ABSTRACT Because photoautotrophic micropropagation systems do not need sugar in the culture media, they are thought to be much easier to scale up than photomixotrophic micropropagation systems. A closed, large-scale photoautotrophic micropropagation for transplant production system has been developed at Chiba University, Japan. New concepts and technologies were adapted to produce high quality transplants at minimum usage of resources, and as scheduled. Newly developed software for production management was used to enhance the efficiency of the transplant production system. Currently, virus-free transplants of sweetpotato ( Ipomoea batatas (L.) Lam.) are vegetatively propagated and produced under sterilized conditions in this system. This system can also be used for production of transplants of any other species including woody plants with a minimum of modification.