Plant growth and responses under totally controlled environmental systems and their application for plant production

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This research presented fundamental knowledge on production of high-value nursery plants using a closed plant production system under energy saving, resource saving, laborsaving and space saving conditions. It also gave basic data for development of a practical system in agriculture. Major outcome are as follows. 1) Growth of tomato plants was promoted by extending the light period daily or by using all-day lighting. 2) Medicinal component concentration and growth of St John's wort ( Hypericum) were affected by temperature, light quality, timing of harvest time and inheritance. The result indicated possibility of commercial production of medicinal plants using a closed plant production system. 3) The effects of leaf area index of tomato seedlings and ventilation on water use efficiency and CO2 use efficiency in a closed system were investigated and a method to increase these efficiencies was proposed. 4) An advanced fogging system for greenhouse cooling was developed using a new control algorithm. Effective combination of the cooling system and a new CO2 enrichment system was proposed to maintain suitable temperature, relative humidity and CO2 concentration at optimal levels in a greenhouse. 5) It was found that using a closed plant production system enables production of seedlings at a high planting density and shortening of period of seedling production.