Water balance of the closed-type transplant production system with artificial lighting was investigated. Sweetpotato (Ipomoea batatas (L.) Lam. cv. Beniazuma) plants were grown for 15 days at photosynthetic photon flux (PPF) on the tray surface of 100, 200 and 300 μmol m^-2 s^-1 on days 0-2, 3-11 and 12-14, air temperature of 30°C, CO₂ concentration of 1000 μmol mol^-1, relative humidity of 80/100% (photoperiod/dark period) inside the system and photoperiod of 16 h d^-1. Daily amounts of evapotranspirated and dehumidified water were increased with time due to increases in evapotranspiration area and PPF. Daily amount of dehumidified water was 90-95 % of the sum of evapotranspirated and humidified water. The amounts of irrigated, evapotranspirated, humidified and dehumidified water during the experiment were 49.5, 36.7, 24.3 and 55.9 kg m^-2, respectively. Water contents of plants and soil at the end of the experiment were 1.6 and 10.8 kg m^-2, respectively. Water utilization efficiency of the system was 0.93. These results show the amount of water use for transplant/plant production can be decreased to 24% of the amount of irrigated and humidified water when dehumidified water was reused for irrigation and humidification. Thus, the closed-type transplant production system is suitable for minimizing the water use in transplant/plant production.

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The CO₂ balance of a closed-type transplant production system with artificial lighting was investigated. Sweetpotato (Ipomoea batatas (L.) Lam cv. Beniazuma) plants were grown for 15 days at photosynthetic photon flux on the tray surface of 100, 200 and 300 μmol m^-2 s^-1 on days 0-2, 3-11 and 12-14, air temperature of 30°C, CO₂ concentration of 1000μmol mol^-1, relative humidity of 80/100% (photoperiod/dark period) inside the system and photoperiod of 16h d^-1. The CO₂ concentration inside the system during dark period was increased with time because of the respiration of plants. The daily amount of supplied CO₂ on day 14 was 10 times larger than on day 1 due to the increasing in net photosynthesis of the plants with passage of days. The amounts of supplied CO₂, assimilated CO₂ by the plants through net photosynthesis and released CO₂ by ventilation to the outside during 15 days were 6.1, 5.6 and O.5 mol m^-2, respectively. These results show that the CO₂ utilization efficiency is more than 7-30 times higher in the closed type transplant production system than in the open type system (i. e. greenhouse), and the closed-type transplant production system is profitable for minimizing the amount of supplied CO₂ in plant/transplant production.

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A new irrigating and soil-warming cultivation system was developed. There was only one porous ceramic pipeline that was used simultaneously as an irrigating pipe and as a warming pipe in this developed system. The cultivation experiment with lettuce verified that this system was practical for irrigating and warming soil simultaneously. Because the irrigating was also from the heating pipe, there was not the problem of the soil drying around the pipe. On the basis of surveying the longitudinal and cross-sectional temperature distributions in the bed soil, the heat sources for heating soil were analyzed under different conditions. The relationship between the soil temperature and the circulating water temperature was also studied in different air temperatures. The required water temperature for warming soil was obeyed to the power function of the air temperature in this ceramic pipe system. When the lowest air temperature at night was not less than 6.6°C, 30.0°Cwater was enough if the soil was warmed only to 15°C. The growth and yields of lettuce in the warming treatment were significantly better than those in the no-warming treatment.

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樹上および追熟中のトマト果実を対象に, 理化学的測定および官能検査を行い, 色による食味の定量的評価の可能性を検討した.得られた結果は次のとおりである.
(1) 樹上果実と追熟果実の着色パターンが異なり, 追熟果実は樹上果実より着色が均一に進んだ.温度20℃, 相対湿度85%の条件下で催色期に採取した果実を追熟すると, 7日間でa/b値が0.06から1.70に増加し, 目減りが2%と小さかった.
(2) 果汁の糖度は, a/b値が0.79以上の樹上果実では4.9Bx°と一定であり, 追熟果実ではa/b値が0.79の時に5.3Bx°の最大値が得られた.pHは樹上果実と追熟果実とともにa/b値の増加に伴って上昇した.
(3) 追熟果実はほとんどの官能検査内容について, a/b値が高いほど, 得点が高かった.同一のa/b値において, 樹上果実は追熟果実より高い評価を得た.樹上果実と追熟果実の食味はそれぞれのa/b値により定量的に評価しうることが明らかになった.

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19～23℃での培地温制御がガーベラ (Gerbera hybrida Hort.)'ニニ'の生育・開花に及ぼす影響について, 葉の水分状態および光合成速度ならびに乾物の分配と蓄積の観点から検討した.クラウン (短縮茎) 当たりに着生した花序数は1.8～2.0で, 実験期間中を通じて安定しており処理による差は認められなかった.しかし, 夏季の冷却あるいは冬季の加温といった培地温制御は, 新たに形成されるクラウンの分枝数を増加させることにより切り花収量を増加させると考えられた.培地冷却は, 夏季の昼間の水ストレスを軽減し, その結果気孔コンダクタンスが維持されて光合成速度が高く保たれ, このことがクラウンへの乾物蓄積を促したものと考えられた.一方, 冬季の培地加温は根への乾物蓄積を抑制した.夏季の冷却と冬季の加温は切り花収量に関して, 相加的な結果をもたらさなかった.

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本研究は, 閉鎖系連続光下におけるピーマン'京みどり'の果実生産における炭酸ガス施与の効果について調査したものである.栽培環境条件は, 蛍光灯連続光の光強度150μmol m^-2 s^-1, 気温27±2℃, 湿度70±5%, 炭酸ガス濃度は自然 (340ppm), 800, 1200, 1600ppmとした.播種約45日後に第1番花が開花し, その時点から炭酸ガス施与を開始した.開始後72日間の収穫果数 (20～25gで収穫) はCO₂自然区で個体当たり57果, 800～1600ppm制御区では80～90果となり, 自然区に比べて制御区で有意に増加した.CO₂濃度の制御区間には有意差は認められなかった.地上部の全乾物重に占める果実乾物重の割合は, いずれの試験区でも40%以上を示した.生育は, すこぶる旺盛で節間は2～3cmと極めて短く葉色も濃緑であったが, 炭酸ガス施与開始2か月後には, 1200ppmと1600ppm区において軽微な葉脈間クロロシスが観察された.長期栽培でのCO₂施与は, クロロシスが発生せず収量の向上が期待できる濃度800ppm程度が適当であると推察された.
なお, 果実品質について自然光ガラス温室での同栽培法による6月の収穫果実と比較したところ, 連続光下の果実は乾物当たりのデンプン含有率は低いが, 糖含有率には差がなく, 果皮が硬く, 緑色濃く, つやの強い点が特徴的であった.

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Producing large quantities of microalgae is one of the most limiting factors when developing large-scale culture techniques for shellfish. When artificial light is used for producing microalgae, it is one of the most expensive costs. In this study, we conducted experiments to determine the optimum light intensity and efficient culture protocol for microalga Pavlova lutheri using a 200-liter chamber.
A 200-liter culture chamber was used to determine the average distribution of PPFD. Under two conditions : 1) filtered seawater (control), and2) filtered seawater with culture medium added and 1.0×10⁷ cells·ml^-1 P. luatheri. Average distribution of PPFD for the filtered sea water was 1, 800μmol·m^-2·s^-1 at irradiation of the full light intensity. But when P. lutheri was cultured in the chamber, available photosynthetic area was reduced to a half of the chamber.
P. lutheri was cultured at irradiation of10%, 30%, 60%and full light intensity at 15°C and an aeration of 30l·min^-1. Maximum cell density correlated positively to light intensity with full light regime supporting more than 2.0·10⁷cells·ml^-1.
We conclude that if higher light intensity is used for the chamber, P. lutheri will obtain nigher cell densities. Additionally the control of light intensity is effective method to decrease the production cost of P. lutheri.

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Cypripedium guttatum is one of the most endangered orchids in Japan. In vitro propagation is an important approach for conservation of the plant species. Generally, Cypripedium in vitro propagation is unstable, especially using immature seeds. Therefore, an in vitro propagation system that protocorm produces stable germination is required.
In this study, one of the weather factors was tested to obtain stable immmature seeds for seedling production. From statistical analysis of the weather data, it was suggested that solar radiation affected the ripening of Cypripedium seed. From simulations of cumulative solar radiation, a seed 46 days after pollination is suitable for in vitro propagation in Akita.
Using a seed 47 days after pollination of Cypripedium guttatum, seedlings were grown in hormone free 1/3 MS agar medium. In the case of adding 0.2 mg/L BAP, multiple shoots were observed. For root elongation of the seedling, hormone free medium was preferable to adding 0.2mg/L NAA.

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Recently, LED is being used as a light source for the cultivation of plants. However, the temperature rise of LED due to heat generation reduces the photosynthetic photon flux (PPF) of LED. Therefore, it is important to develop a method for heat removal. We report the effects of temperature rise in LED and heat removal by passing air either to the LED lamps or to the space between two circuit boards on PPF.
We found that the PPF of LED is reduced by more than 30% in half an hour after lighting under the condition without heat removal. Thus, the method of heat removal attempted in this study seems to be effective for small scale light sources.

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The effects of growth regulators added to MS media on bulb formation of lily (Lilium×formolongi hort.) seedlings were examined. Abscisic acid (10 μM) and higher concentrations (1 and 10 μM) of methyl jasmonate (Me-JA) were effective for bulb formation of lily seedlings.
Aminoethoxy-vinylglycine (AVG : ethylene inhibitor) significantly inhibited leaf formation. Leaf formation increased by addition of 10 μM 1-aminocyclopropane-1-carboxylic acid (ACC : ethylene precursor). The effect of Me-JA on bulb formation of seedlings did not inhibited by 10 μM ACC or 1 μM AVG. It is suggested that both Me-JA and ABA are effective for induction of in vitro bulb formation of Lilium×formolongi hort..

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