後藤 英司

Red perilla (Perilla frutescens) is used as food, stomachic and antitussive crude drugs, and anti-allergy supplements. The major bioactive compounds of red perilla are perillaldehyde (PA), rosmarinic acid (RA), luteolin (LU), and anthocyanin (ANT). In this study, we investigated the effects of 6 days low (10, 12, and 15°C) and control (20°C) nutrient solution temperature (NST) treatments on plant growth and major bioactive compound concentrations in red perilla leaves at the node position. No significant difference was detected in the dry weight of leaves of the main shoot, which is the main part harvested, among the treatments. However, leaf water content (%) tended to decrease with a decrease in NST, especially in plants grown at 10°C NST, which exhibited values significantly lower than those of plants grown at 15°C and 20°C NSTs. PA and ANT concentrations in the 3rd to 5th nodes did not differ among treatments. Conversely, RA concentration increased with a decrease in NST, irrespective of the node position. LU concentration at 10°C NST was the highest in all treatments, irrespective of the node position. This suggested that the production of bioactive compounds under the low NSTs differed depending on leaf maturity stage and compound. Additionally, the contents of RA and LU in the whole plant increased because there was no reduction in growth of the harvested part under the low NSTs. Therefore, 6 days exposure to root-zone temperatures at 10°C appears to be an effective method to increase both RA and LU concentrations and their contents in the whole plant of red perilla for its use as a crude drug or medicinal material.

Continuous fog spraying reduces the variations in the temperature and humidity, thereby reducing the adverse effects of intermittent spraying. A rate-controllable fog-generation method can be used to produce continuous fog spraying. The fog-generation rate can be easily controlled by controlling the pressure of a compressor with an inverter. The ventilation rate is also an important factor for controlling fogging systems because the air cooling and evaporation rate of the fog are affected by the ventilation rate. Control of the fog-generation and ventilation rates can efficiently decrease the air temperature in a greenhouse. However, there are few studies using both a rate-controllable fog-generation method and forced ventilation. In this study, we controlled both the fog-generation rate and the rate of forced ventilation. An experimental greenhouse installed with a fog cooling system and fans was used in the experiment. The fog-generation rate and fan speed were controlled by inverters connected to each device on the basis of the environmental conditions outside and inside the greenhouse, and the target air temperature inside the greenhouse. As a result, a rate-controllable fog-generation method that controls both the fogging and ventilation rates can produce continuous fog spraying and control the air temperature inside the greenhouse with low water and energy consumption.

From a global perspective, the number of countries that use greenhouses and cultivated areas are increasing. When applying environmental controls such as heating, cooling, ventilation, and CO enrichment in greenhouses under various climatic conditions, the estimation of energy consumption and other resources is important in both greenhouse design and the selection of a candidate crop. The objective of this study was to develop a new simulation model to predict greenhouse environments under given weather conditions. To achieve this objective, we developed an integrated model for greenhouse climates by using the transient system simulation program (TRNSYS). TRNSYS has a modular structure for use within the architectural design field. It includes many of the components for thermal and electrical energy systems, and handles the input of weather data. We modified and added components that modeled ventilation, shading, heating, evaporation cooling, and evapotranspiration, and calculated the heat energy balance necessary for predicting inside air temperature and humidity. Environmental conditions inside the greenhouse were simulated using meteorological and plant data. We evaluated the developed model by using an experimental greenhouse with the above environmental controls installed. We applied the model to greenhouses under various climatic conditions in different countries, mainly Asia. We estimated the energy required for heating and/or cooling and CO and water in order to control the internal environmental conditions at the targeted values under given weather conditions. The study indicates that the model is an effective tool for making strategic decisions in the installation of greenhouses from the viewpoint of energy and resource application. 2 2

播種後14日目に，栽植密度は12.9株m^-2とした上で，赤青LEDを用いて，150，250 μmol m^-2 s^-1としたPPFDと0.18, 0.23としたB/R比を組み合わせた4区を設けて，赤系リーフレタスを収穫サイズまで育成し，収穫までに要する照明電力量を算定した．栽植密度12.9株 m^-2では，PPFD 150 μmol m^-2 s^-1ではB/R比0.23区で0.18区よりも収穫までに要する照明電力量は少なかった．PPFD 250 μmol m^-2 s^-1ではB/R比による差はみられなかった．しかし，栽植密度を最適化した条件では，PPFD にかかわらずB/R比0.18区でB/R比0.23区よりも収穫までに要する照明電力量は少なかった．また，栽植密度12.9株m^-2では，PPFD 150 μmol m^-2 s^-1の方が250 μmol m^-2 s^-1よりも収穫までに要する照明電力量は少なかったが，栽植密度を最適化した条件では，PPFD 250 μmol m^-2 s^-1の方が照明電力量は少なくなる傾向がみられた．本試験の範囲において，照明電力量を抑えてレタスを育成するのであれば，照明ロスがないように植物体を配置した上で，PPFDを250 μmol m^-2 s^-1，B/R比を0.18として育成するのがよいことが示された．本試験では，相互遮蔽の起こらない栽培条件で得られた測定値を用いて，栽植密度を最適化した場合の照明電力量を推定する手法を提示した．本解析方法は，実際の栽培現場で，試験回数を最小限に抑えて，効率的に最適な光環境条件を探索し，消費電力量を予測することができるため，実用的にも有用と考えられた．

Japanese honeysuckle is an evergreen vine that grows naturally in Japan and East Asia. The buds and leaves of this plant are used as crude drugs known as Kinginka and Nindou, respectively, in Japan and East Asia. The medicinal compounds are chlorogenic acid and luteolin, which have antiviral, anticancer, anti-inflammatory, and antioxidant activities. The optimal environmental conditions for growing Japanese honeysuckle have remained unknown thus far. The aim of this study was to investigate the effects of supplemental lighting in winter greenhouse on growth and production of medicinal compounds in Japanese honeysuckle. For that purpose, we cultivated Japanese honeysuckle plants in a greenhouse using supplemental lighting from high-pressure sodium lamps. During the experiment, the daily light integral was maintained at 10 mol m d by controlling the irradiation period of supplemental lighting from the evening until midnight. The total dry weight and total leaf area of plants subjected to 55 d of supplemental lighting were significantly higher than those in control plants. The number of flower buds was significantly higher in treated plants, and then, there was no difference in the concentration of chlorogenic acid and luteolin between the two groups. In conclusion, supplemental lighting is a useful method for winter cultivation of Japanese honeysuckle that increases the yield of flower buds and does not decrease the concentration of main medicinal compounds. -2 -2

Light manipulation is a key environmental control method to in crease functional phytochemical concentrations and antioxidant capacity in leaves of leafy vegetables. Here, we evaluated the effect of UV light on the accumulation of functional phytochemicals in the leaves of red leaf lettuce. We developed a novel lighting system, consisting of UV LEDs as a UV light source and red LEDs as a photosynthetic light source. Red leaf lettuce grown under white light was used as the plant material. Three peak wavelengths (310, 325, and 340 nm) of UV lights at 0.5 W m-2 for 16 h were added to the white light for 3 d prior to harvest. Anthocyanin concentration and ORAC value of the leaves were measured every 8 h. mRNA gene expression of chalcone synthase (CHS) and the flavonoid 3-O-glucosyltransferase (UFGT) were also analyzed every 8 h. Anthocyanin concentration was significantly higher at 310 nm compared with 325 and 340 nm. Total ORAC values of the UV treatments were higher than in the control. CHS was highest at 310 nm, followed by 325 nm. UFGT increased with time, similarly to the anthocyanin concentration. These results indicated that UV-B light stimulated the biosynthesis of anthocyanin and other antioxidant polyphenols. From this research, we concluded that addition of UV light 1 to 3 d prior to harvest is effective for the production of functional phytochemical rich lettuce.

We studied the effects of varying light quality on the flowering,photosynthetic rate and fruit yield of everbearing strawberry plants (Fragaria×ananassa Duch. ‘HS138’),which are long-day plants,to increase the efficiency of fruit production in plant factories. The plants were grown under continuous lighting using three types of blue and red LEDs (blue light peak wavelength: 405,450,and 470 nm; red light peak wavelength: 630,660,and 685 nm) during the nursery period. All blue light from the various peak LED types promoted more flowering compared with red light (630 and 660 nm except for 685 nm). The longer wavelength among the red light range positively correlated with earlier flowering,whereas the number of days to anthesis did not significantly differ among blue LED treatment wavelengths,irrespective of peak wavelength. The result of a similar experiment using the perpetual flowering Fragaria vesca accession Hawaii-4 representing a model strawberry species showed almost the same pattern of flowering response to light quality. These results suggest that long-day strawberry plants show similar flowering response to light quality. The photosynthetic rate under red light (660 nm) was higher than that under blue light (450 nm). However,the plants grown under red light showed lower photosynthetic capacity than those grown under blue light. Although the light color used to grow the seedlings showed no difference in the daily fruit production,blue light irradiation during the nursery period hastened harvesting because of the advance in flowering.

A completely closed plant production system was developed to produce genetically modified rice plants. Plant cultivation at high planting densities can sometimes cause mutual shading of plant leaves and restrict air movement inside the canopy. In this study, we performed growth experiments to determine the optimum air current speed to enhance growth. A prototype closed plant production system was used; this system included a cultivation room and hydroponic containers. Rice plants were planted at a density of 40 m . The air from an air-conditioning system flowed through the plant canopy in a horizontal direction from the air supply outlet on the room wall. Several types of fans with different flow rates were placed at an upstream position to vary the air current speed inside the canopy. In experiment 1, the air current speed at 40 cm above the cultivation panel was set to 0.40-1.20 m·s , and the plants were cultivated under these conditions until the heading stage. The dry weight and leaf area decreased with increase in air current speed. Thus, air current speed higher than 0.40 m·s was thought to cause excessive transpiration from the leaves. In experiment 2, the speed was set to 0.03-1.30 m·s , and the plants were cultivated until the harvest stage. The rice yield was higher at 0.40 and 1.30 m·s than at other air current speeds. This was probably because low air current speed restricted vegetative growth and limited the translocation of photoassimilates in the leaves to the seeds. Our study showed the importance of controlling the air current speed inside a rice plant canopy and indicated that approximately 0.4 m·s of air speed was the most suitable to enhance growth and increase rice yield in a closed cultivation system. -2 -1 -1 -1 -1 -1

Here, we evaluated the effect of light quality on vegetable growth to determine the efficiency of light energy utilization on photosynthesis in plant factories. Specifically, we measured the gross photosynthetic rate (P) of butterhead lettuce, green perilla, red perilla, and tomato seedlings under a range of different LED peak wavelengths using the assimilation chamber technique. The light-source system included 6 peak LED wavelength types: 405, 465, 530, 595, 660, and 735 nm. The system produces light composed of different combinations of the 6 wavelength ranges. Photosynthetic photon flux (PPF) values of 160 and 320 μmol·m ·s with 4 peak wavelengths (465, 530, 595, and 660 nm of 40 and 80 μmol·m ·s , respectively) were set as the controls. Then, the PPF conditions of 120 and 240 μmol·m ·s were determined by turning off 1 of the 4 peak LEDs. By using the difference between P at 120 and 160 μmol· m ·s and 240 and 320 μmol·m ·s , at a given wavelength, an incremental increase in P at low and high PPF levels was calculated, and expressed as absorbed CO2 per added photon. The results showed that the highest incremental increase was obtained at 660 nm for all 4 vegetables. For red perilla and tomato, a significantly low incremental increase was obtained at 465 and 530 nm. The anthocyanin-rich leaves of these 2 plants are known to absorb large quantities of blue and green light in the epidermis, which led to lower P values at these wavelengths. The difference in the incremental increase was smaller at 320 μmol·m ·s than at 160 μmol·m ·s for all 4 vegetables. In conclusion, we suggest that the suitable wavelength to increase P varies depending on crop type, light quality history, and light intensity. -2 -1 -2 -1 -2 -1 -2 -1 -2 -1 -2 -1 -2 -1

In this paper, the technology of the solar light-guide plate is introduced and is used for the windows of the greenhouse. The maximum generated power of the solar light-guide power module is measured outdoors and the experimental results are compared with the simulation results. With the change of the azimuth and elevation angles of the sunlight day by day, the maximum generated power of the solar lightguide power windows for different seasons is also predicted.

The objective of this study was to develop a simulation model to evaluate environmental controls in a tomato greenhouse after considering the local conditions of East Asia, including Japan. To achieve this objective, we used the simulation software TRNSYS to develop a simulation model for the greenhouse climate. We selected and modified the components that modeled ventilation, and calculated the heat balance necessary to predict the inside air temperature and humidity. A fog cooling module and an evapotranspiration module for summer production of tomato was added. The model was validated with an experimental greenhouse with a fog cooling system. The fog cooling module included parameters for rate of fog application. The evapotranspiration module predicted evapotranspiration from the vegetation surface based on meteorological datasets consisting of hourly averaged values for solar radiation, outside air temperature, and relative humidity. The results showed that the simulation output for the inside air temperature corresponded with the measured values with good accuracy. The simulation model combined with the fog cooling and evapotranspiration modules could accurately simulate environmental conditions in a greenhouse with a fog cooling system.

One reason why the effect of light quality on plant growth remains unclear is that light quality affects photosynthesis and photomorphogenesis during long-term cultivation, and in some cases, photomorphogenesis may affect the plant growth rate. Thus, in this study, we evaluated the effect of blue/red (B/R) ratio and light intensity (photosynthetic photon flux [PPF]) on photomorphogenesis by separating the effects of light quality and PPF on photosynthesis. Red leaf lettuce was cultivated under lightemitting diodes (LEDs). Nine test treatments were established at 11 days after sowing (DAS) by using a combination of PPF values of 100, 200 and 300 μmol·m ·s and B/R ratios of 0.18, 0.23 and 0.33 with a mixture of blue (450 nm) and red (660 nm) LEDs. Under 100 μmol·m ·s PPF, the total dry weight was not different among the B/R ratios. Under 200 and 300 μmol·m ·s PPF, the total dry weight at 21 and 25 DAS was the highest at B/R ratios of 0.23 and 0.33, respectively. The total dry weight was the highest at these B/R ratios mostly because of the high net photosynthetic rate and large amount of light received by the leaves. The change in leaf shape changed to the amount of light received by the leaves. It was shown that the difference in growth rate was due to a strong change in leaf morphogenesis under different B/R ratios, because the change in leaf shape changed the amount of light received by the leaves. -2 -1 -2 -1 -2 -1

The impact of variability in light intensity (photosynthetic photon flux, PPF) at a closed plant factory with artificial light on fluctuations in growth and nutrient content (ascorbic acid, β-carotene, calcium and iron) of 3 types of leafy vegetables was investigated to examine the possibility of nutritional labeling for leafy vegetables. Chingensai (Brassica rapa L. var. chinensis), Komatsuna (Brassica rapa L. var. peruviridis), and Rocket (Eruca vesicaria L.) were cultivated in a hydroponic culture system under artificial conditions (white fluorescent lamps as light source). Four test treatments were established with PPF values of 160, 200, 240, and 280 μmol m-2·s . Fresh and dry weights were greater with higher PPF values for all plant species. However, no impact of PPF was observed on the dry matter ratio or the proportion of the fresh weight of leaf blades in relation to the total fresh weight of plants. Except for ascorbic acid concentration in Chingensai and β-carotene and iron concentrations in Rocket, no significant differences in nutrient concentrations (fresh or dry weight basis) were revealed in relation to PPF. The coefficient of variation for nutrients was relatively smaller than that of fresh and dry weight in all crops. There were only small fluctuations in nutrient concentrations attributable to variation in PPF in these leafy vegetables, particularly in Chingensai and Komatsuna, which have a uniform shape and growth rate. Thus, nutritional labeling in leafy vegetables cultivated in plant factories is considered possible. -1

NIR-excluding materials have high PAR transmittance and low NIR transmittance by virtue of absorbing or reflecting NIR selectively. Therefore, compared with standard shading materials, shading with NIR-excluding materials leads to a reduction in air temperature inside the greenhouse without a reduction in PAR. Several studies have demonstrated the positive effects of shading using NIR-excluding materials on plant growth and crop yield; however, the mechanism of the effect is still unclear. In this study, we investigated the effects of shading by NIR-excluding materials on the growth, photosynthesis, and transpiration of tomato plants grown in a greenhouse. Two types of NIR-excluding films with different average PAR and NIR transmittances (PAR/NIR = 70%/66%, 80%/6%) were used as coverings above the canopy. Leaf temperatures under NIR-excluding materials were lower than those under non-shading material. This was because the NIR-excluding materials cut off both NIR and incident PAR to the plant canopy compared with non-shading material. It appears that the photosynthetic rate under conditions of high leaf temperatures decreased with an increase in respiration rate; however, there was no significant difference within the range 27-33°C. The transpiration rate of tomato plants increased as solar radiation over the canopy increased. When solar radiation above the canopy was the same, it was assumed that the amount of heat absorbed by leaves and the transpiration rate both increased because the ratio of NIR to total solar radiation decreased and the ratio of PAR to total solar radiation increased under NIR-excluding materials compared with non-shading materials. However, there was no significant difference in the transpiration rate in these experiments. It is suggested that the photosynthesis and transpiration of tomato plants were more strongly influenced by the decrease in air temperature or decrease in incident solar radiation than by the change in the amount of NIR.

Fog cooling systems with natural ventilation are a type of evaporative cooling technique that is widely used in Japan. One drawback of these systems is that it is difficult to maintain the greenhouse air temperature at its optimum range in summer using the conventional single-fluid nozzle system because it has a low cooling efficiency and produces a high risk of pathogen invasion due to excessive wetting of the plant foliage. Therefore, we introduced a twin-fluid nozzle system as an alternative fogging system. This system affords a higher evaporation ratio and a lower degree of plant foliage wetting because it generates fog droplets with diameters smaller than those generated by single-fluid nozzles. We installed these two types of fogging systems in tomato greenhouses and investigated the different aerial environments that they produced. We observed that the twin-fluid nozzle system maintained the air temperature at the same level as that maintained by the single-fluid nozzle system. We also observed that the single-fluid nozzle system significantly inhibited the evapotranspiration in the tomato plants due to wetting of the plant foliage, whereas the evapotranspiration rate when using the twin-fluid nozzle system was 70-100% higher.

We assessed the effects of light intensity (photosynthetic photon flux [PPF in µmol˙m ˙s ]) and number of irradiated leaves on photosynthesis and the fruit growth of individual tomato plants to develop supplemental LED lighting techniques for greenhouse tomato production. In Experiment (Exp.) 1, three PPF levels (P200, P500, and P1000) were applied to a post-anthesis tomato plant for three weeks, each plant pruned to have one leaf and one truss with three flowers. The fruit set and leaf and fruit dry-weight increased with increasing PPF; however, after P500 and P1000 treatments, the leaves showed signs of stress and accompanying disorders. Thus, to increase the fruit set ratio and growth rate of tomato fruits and plants, the total amount of irradiation received by each plant should be increased by increasing the number of irradiated leaves, rather than raising the PPF per leaf. For prolonged cultivation, P200 was the optimal PPF per leaf under the tested treatments. Exp. 2 used standard tomato plants with no leaves or trusses removed. We used an assimilation chamber to examine the effect of the number of leaves receiving P200 irradiation on the photosynthetic rate (Pn) per plant (above ground part). The Pn per plant in treatments where one and two leaves were irradiated by supplemental LED lighting were, respectively, 12 and 28% higher than that in the control (only top lighting). Therefore, fruit growth and yields in tomato cultivation may be raised via acceleration of photosynthesis by increasing the number of leaves that receive P200 irradiation rather than by increasing PPF. © 2013, The Society of Agricultural Meteorology of Japan. All rights reserved. -2 -1

本試験では, 人工光型植物工場を用いたイチゴの栽培における初期コストの削減および栽培期間の短縮(ランニングコストの削減)を目的として, 連続明期およびその開始時期が四季成り性イチゴ苗(Fragaria×ananassa Duch. 'HS138')の花成および生育に及ぼす影響について調査した. 処理光源には, 花成促進効果が報告されている青色光を多く含む青色蛍光灯を用い, 日積算光量(Daily light integral; DLI)を13 mol m^-2 d^-1とした. 組織培養苗を水耕装置に移植後21日目から16時間明期または連続明期下で栽培したB16区とB24区, 加えて, 連続明期処理の開始を16日早め, 移植後5日目から行ったEB24区を設けた. 処理区を通じて全ての株が開花した時点で試験を終了した(連続明期処理の開始後71日目). その結果, B24区およびEB24区ともに, B16区の開花日より約20日早く開花した. 移植後21日目から処理を開始したB24区の葉面積は約50 cm², 移植後5日目から連続明期処理を開始したEB24区の連続明期処理の開始時の葉面積は約10 cm²だった. 連続明期処理の開始時期を16日早めたEB24区で花成が促進されなかったのは, 花芽分化するにはある程度の成長量(葉面積)や葉齢を確保し, 幼若相を脱する必要があるためと考えられた. 試験終了時における総乾物重にB16区およびB24区で差はなく, 連続明期下においても生理障害なく, 連続明期は16時間明期と同等の成長量を得られることが明らかとなった. 同じDLIの場合, 連続明期は16時間明期に比べ照明器具の設備コストを2/3にすることが可能である. これらのことから, 四季成り性イチゴの育苗期における連続明期下での栽培は, 16時間明期での栽培に比べ, ランニングコストの削減だけでなく, 初期コストの削減も可能であることが示された.

The transgenic everbearing strawberry (Fragaria·ananassa Duch. 'HS 138') can be cultivated in a closed plant production system to produce functional proteins that enhance human immune functions. In this study, we investigated the effects of light quality on fruit growth and the concentration of human adiponectin (hAdi) at three mature stages in transgenic strawberry. hAdi plants were exposed to 3 different light qualities (white [W], blue [B], and red [R]) for a 16-h light period under fluorescent lamps during the flowering and harvest stage; fruits were then harvested at three different mature stages (small green, turning white, and mature red). hAdi concentration increased with fruit maturation, and the mature red stage fruit from the R light treatment group had a significantly greater concentration of hAdi on a fresh-weight basis than all other treatments. There was no relationship between hAdi concentration and fruit fresh weight and the number of days from anthesis to harvest. Although the factors that promoted the production of the functional hAdi proteins were not clear in this study, the results suggest that the fruit growth stages of the transgenic strawberry differed in their response to light quality. For hAdi plants, exposure to red light resulted in the greatest level of functional protein production under the tested treatments.

The root of Chinese licorice (Glycyrrhiza uralensis) is used worldwide as a medicinal herb. The goal of this study was to understand changes in the concentrations and compositions of four medicinal compounds-glycyrrhizic acid (GL), liquiritin (LQ), liquiritigenin (LG), and isoliquiritigenin (ISLG)-in the root of Chinese licorice during post-harvest treatment. The effects of post-harvest storage temperatures (-80, -30, -13, 4, and 25C) and drying temperatures (30, 40, 50, and 60C) on concentrations of the four medicinal compounds were investigated. GL and LQ concentrations in roots stored at -30 and -13C for 1-2 weeks tended to be 4% to 13% higher than GL and LQ concentrations in roots dried directly in a vacuum freeze dryer (controls). LG concentrations in roots stored at 4C for 2 weeks were nearly 60-fold higher and ISLG concentrations at 25C for 1 week were 10-fold higher than LG and ISLG concentrations in the controls. In addition, low temperature (30 and 40C) drying compared to vacuum freeze drying (controls) increased LG and ISLG concentrations without decreasing GL and LQ concentrations. This study provided an approach to increase the target compound concentrations in Chinese licorice for different market demands (drugs, cosmetics, and food).

The main root of Chinese licorice (Glycyrrhiza uralensis) is used worldwide as a medicinal material and flavoring agent. This study aimed to determine UV light stress conditions effective for increasing the concentrations of four medicinal ingredients - glycyrrhizic acid (GL), liquiritin (LQ), liquiritigenin (LG), and isoliquiritigenin (ISLG) - and the main root dry weight of Chinese licorice. All UV treatments were compared to exposure to a white fluorescent lamp as a control. For UV treatments, the white fluorescent lamp was supplemented with either UV-A or UV-B fluorescent lamp or a combination of both. Low intensities of UV-A and UV-B were applied for longer treatment periods, while high intensities of UV-A and UV-B were applied for shorter periods. The control was set in each UV treatment for a same period. The dry weights of the main roots as the medicinal part in each UV treatment were not significantly different from the weights of the controls. The concentrations of the four medicinal ingredients in the high intensity UV-B irradiation treatments (BH and AHBH) over 5 or 6 days were 50-70% higher than those in their respective controls. LG and ISLG concentrations in the medium intensity combined UV irradiation treatments (AHBL and ALBH) over 10 days were 140 and 350%, respectively, greater than the levels in their respective controls. These results suggest that UV-B or combined UV-A and UV-B irradiation with white light over 5 to 10 days is more effective than irradiation of white light alone in increasing the contents of GL, LQ, LG, and ISLG in dried main roots without inhibiting the growth of the main root. © ISHS 2012.

We studied the effects of light quality and light period on the flowering of everbearing strawberry plants (Fragaria × ananassa Duch. 'HS138') during the nursery period, to increase the fruit production efficiency of transgenic strawberry plants in a closed plant production system. The plants were grown under a 16-h light period versus continuous lighting illuminated by white fluorescent lamps, blue LEDs, or red LEDs. Flowering was significantly earlier in plants grown under (1) blue LEDs compared to red LEDs, irrespective of light period, and (2) continuous lighting compared to the 16-h light period, irrespective of light quality. The results show that blue light advances the flowering of everbearing strawberry plants compared to red light. While continuous lighting by blue LEDs advanced flowering and shortened the vegetative growth period, the fruit yield of plants grown under continuous lighting by blue LEDs was higher than that of plants grown under our standard cultivation conditions (i.e., 16-h light period by white fluorescent lamp). In conclusion, shortening the nursery period by adjusting light quality and light period increased fruit production efficiency compared to standard cultivation conditions. © ISHS 2012.

Year-round tomato cultivation needs high-quality seedlings of which stem length and node position of the first flower truss are controlled at suitable values. The objective of this study was to develop a method for controlling stem elongation and flowering of tomato seedlings in a closed seedling production system using light emitting diodes (LEDs). To this end, we measured the growth parameters of tomato seedlings grown under a mixture of blue (B; peak wavelength, 450 nm) and red (R; peak wavelength, 660 nm) LEDs to determine the optimum light conditions. We conducted two experiments to investigate whether the blue/red (B/R) ratio or blue and red light quantity affects morphogenesis. In experiment 1, the stem length at a 1.0 B/R ratio was shorter than that at a 0.1 B/R ratio. The node position of the first flower truss at the 0.1 B/R ratio was lower than that at the 1.0 B/R ratio. The net photosynthetic rate increased upon the decrease of the B/R ratio. Therefore, it appeared that flowering promotion was affected by photosynthesis. In experiment 2, stem elongation under 25, 50, and 75 μmol m s of red light with a constant quantity of blue light remained similar regardless of red light quantity. These results suggested that stem elongation depended on blue light quantity. Thus, LED irradiation at 75 μmol m s of blue light and a B/R ratio of <1.0 would suppress spindly growth and promote flowering during tomato seedling growth. © ISHS 2012. -2 -1 -2 -1

Plant factories where leafy vegetables are cultivated until harvest in closed systems with artificial lighting were proposed, developed, and implemented in Japan during the 1980s. During the 1990s, the products from these factories received high evaluations by the food service industry, to which they primarily catered. During the 2000s, commercial production of nursery plants of fruits and vegetables was initiated in plant factories. Since the late 2000s, plant factory technology has been introduced worldwide, particularly to Asian countries. Plant factories also provide good cultivation systems for the production of medicinal plants and genetically modified crops for pharmaceutical use. In late 2000s, light-emitting diodes (LEDs) were introduced to plant factories as a more efficient light source. LEDs are expected to reduce the electricity costs of lighting and cooling because they have a higher efficiency of converting electric power to light power and exert lower cooling loads than conventional light sources. To achieve plant production in plant factories by using LEDs, more achievement of plant research is required taking engineering and plant physiological approaches, in areas such as the creation of optimal LED lighting systems, promotion of photosynthesis, control of gene expression, photomorphogenesis, and synthesis of secondary metabolites. This study reviews recent research status and achievements regarding plant production in plant factories with artificial lighting and introduces plant research topics related to LEDs utilization. © ISHS 2012.

CO2施用システムを用いて換気窓開放時の大規模温室内のCO2濃度を温室外のCO2濃度と同程度に維持できるか調査した。また,その際のトマトの成長量および収量を調査結果からCO2施用の効果を評価した。CO2施用システムを用いることで,換気窓開放時に低下した大規模温室内のCO2濃度を温室外CO2濃度と同程度まで高め維持できた。また同時に,CO2施用によってトマトの成長量および収量が増加した。

Gene-to-gene coexpression analysis provides fundamental information and is a promising approach for predicting unknown gene functions in plants. We investigated various associations in the gene expression of tomato (Solanum lycopersicum) to predict unknown gene functions in an unbiased manner. We obtained more than 300 microarrays from publicly available databases and our own hybridizations, and here, we present tomato coexpression networks and coexpression modules. The topological characteristics of the networks were highly heterogenous. We extracted 465 total coexpression modules from the data set by graph clustering, which allows users to divide a graph effectively into a set of clusters. Of these, 88% were assigned systematically by Gene Ontology terms. Our approaches revealed functional modules in the tomato transcriptome data; the predominant functions of coexpression modules were biologically relevant. We also investigated differential coexpression among data sets consisting of leaf, fruit, and root samples to gain further insights into the tomato transcriptome. We now demonstrate that (1) duplicated genes, as well as metabolic genes, exhibit a small but significant number of differential coexpressions, and (2) a reversal of gene coexpression occurred in two metabolic pathways involved in lycopene and flavonoid biosynthesis. Independent experimental verification of the findings for six selected genes was done using quantitative real-time polymerase chain reaction. Our findings suggest that differential coexpression may assist in the investigation of key regulatory steps in metabolic pathways. The approaches and results reported here will be useful to prioritize candidate genes for further functional genomics studies of tomato metabolism. © 2012 American Society of Plant Biologists. All Rights Reserved.

A new tomato growth model was developed based on an existing growth model to predict the growth and yield of tomato plants cultivated with a low node-order pinching system at high plant density, under annually variable environmental conditions in Japan. Over a 5-year period, we obtained the growth and yield data of 2 tomato Japanese cultivars in a large-scale commercial greenhouse, in correlation with environmental data (i.e., radiation, air temperature, humidity). We calculated the wink strength of each vegetative organ and fruit and determined cultivar specific constants, by modifying an existing process growth model developed for long-term cultivated tomatoes. The accuracy of the modified simulation, regarding the growth and yield of tomato plants, cultivated with a low node-order pinching system at high plant density, was improved by the modification of cultivar specific constants and calculation methods of fruit sink strength, with an overall error of just 16.5%.

A continuous CO measurement system was developed to monitor the CO exchange rate of the whole canopy of grafted transplants using semi-open multiple chambers. Air heating or cooling and humidification inside a healing box were under control, if needed. To test the system, the gas exchange rate of the cucumber (Cucumis sativus L.) transplants grafted onto pumpkin (Cucurbita maxima cv. 'New-Shintozwa') was analysed. During the healing and acclimatisation of the grafted cucumber plants, the air temperature in the box remained constant at night but ranged above 1°C of a set value under high humidity in daytime. The relative humidity was kept within the set point during the daytime, and it nearly reached 100% at night when not controlled. The cucumber seedlings were exposed to different water stresses before grafting, and the water potentials of each treatment were -0.579 (non-stressed), -0.814 (mildly water-stressed), and -0.870MPa (strongly water-stressed) on grafting. At the water-stressed scions, leaf expansion was inhibited by 30.9-53.3% compared with the non-stressed scions. Therefore, the gas exchange rates of the strongly water-stressed scions based on the leaf area were decreased to 72.7% compared with the non-stressed scions. After grafting, the apparent photosynthesis of the transplants of all treatments was negative, with higher respiration in the strongly water-stressed scions during the initial period of healing. However, they turned to positive values and exceeded those of the non-stressed scions from three days after grafting. This result provides critical information that the water column is physiologically connected between the stock and scion within two days after grafting. As a result of water stress, the leaf area and dry weight of the transplants in the strongly water-stressed scions were inhibited by 67.5% and 83% compared with the non-stressed scions at the end of acclimatisation. In contrast, the relative growth rate and graft-take of the strongly water-stressed transplants were slightly increased, which suggests that the water stress prior to grafting alleviated the water demand of the scion. This system may provide useful information for diagnosis at the early stage by monitoring the whole canopy's photosynthesis over a long term. © 2011. 2 2

Sweet basil contains some phenolic compounds such as rosmarinic acid, caffeic acid, and chicoric acid. Our previous study revealed that the rosmarinic acid content was increased by continuous white light irradiation. In this study, we investigated whether light conditions affect the caffeic acid and chicoric acid contents. The content of chicoric acid was increased by light irradiation, and was highest under white light, followed by blue light, and was lowest was under red light. Although the content of caffeic acid was also increased by light irradiation, it was not influenced by light quality. These results indicate that continuous white light increases the polyphenol content of sweet basil, which results in high antioxidant activity.

Cultivation of plants using a controlled environment facility provides the possibility of manipulating different environmental factors in favor of plant optimum growth. The objective of this study was to investigate the effects of different levels of light intensity, light period and CO concentration on photosynthetic rate and growth in leaves of Japanese mint at different ontogenic stages. In experiment I by combining three different light periods (8, 16 and 24 h d-1) and two levels of light intensity (100 and 200 μmol m s ) provided by white fluorescent lamps, six treatments were applied on plants growing in chambers. After 4 weeks, growth parameters were measured destructively. In experiment π, plants were grown in a controlled environment using white fluorescent lamps, providing 12 h d light period and PPF of 100 μmol m s-1. At the end of the 5th week, photosynthetic rate of three leaves in different ontogenic stages was measured under combination of three levels of CO concentration and six PPF levels using a portable photosynthesis measurement system. The results showed that changing light period, light intensity and CO concentration can alter the photosynthetic rate and the consequent growth of Japanese mint. Results imply that increasing light intensity and CO concentration would raise photosynthetic rate of Japanese mint. Moreover, our findings suggest that leaves age as well as the DLI value affects the growth and final yield and should be considered in cultivation management in order to maximize the yield. 2 2 2 2 -2 -1 -1 -2

We investigated the effects of light quality and photosynthetic photon flux (PPF) on spinach biomass production and carotenoid pigments. We showed that, with a PPF of 300 μmol m s , white and/or red fluorescent lamps promoted higher dry mass accumulation in 4 spinach cultivars than did a blue fluorescent lamp. By contrast, with a PPF of 100 μmol m s , the effect of light quality on dry mass accumulation was not significant. The leaf blade dry mass (%) was higher than the leaf stalk dry mass (%) for all treatments used. Light quality and PPF significantly affected β-carotene and lutein concentrations of spinach on a fresh and dry mass basis. We further showed that, with a PPF of 300 μmol m s , applying a blue fluorescent lamp significantly promoted β -carotene and lutein concentrations of spinach on a fresh, and also a dry mass basis. Our results suggest that spinach biomass production and β-carotene and lutein concentrations strongly depend on the PPF. Furthermore, light quality plays a vital role when the PPF is high, but has little effect when the PPF is low. -2 -1 -2 -1 -2 -1

Recently, genetically modified (GM) plants have attracted much attention because of their use in the production of valuable materials, such as pharmaceutical proteins, for humans or livestock. Pharmaceutical products that have been or are being developed include oral vaccines for humans or livestock and agents that prevent lifestyle-related diseases. A closed plant production system is ideal for the propagation of medicinal products. We developed a closed plant production system with artificial lighting for stable accumulation of high concentrations of desired functional proteins in the edible components of strawberry and rice plants. The GM strawberry plant accumulates a functional protein in the achenes and the fruit, which is known to prevent lifestyle-related diseases. The GM rice plant accumulates an oral vaccine in the protein body of the seed. Because responses of GM plants to environmental conditions have not been investigated, we researched the physiological characteristics of plants under artificial conditions; this included the effects of light quality, light intensity, light period, ultraviolet stress, low temperature stress, carbon dioxide concentration, composition and concentration of nutrient solution, and planting density. First, we determined the appropriate environmental conditions for optimizing rice and strawberry plant production of valuable materials in large quantities.

One of the ultimate goals of plant science is to test a hypothesis obtained by basic science and to apply it to agriculture and industry. A plant factory is one of the ideal systems for this trial. Environmental factors affect both plant yield and the accumulation of recombinant proteins for industrial applications within transgenic plants. However, there have been few reports studying plant productivity for recombinant protein in closed cultivation systems called plant factories. To investigate the effects of photosynthetic photon flux (PPF) on tomato fruit yield and the accumulation of recombinant miraculin, a taste-modifying glycoprotein, in transgenic tomato fruits, plants were cultivated at various PPFs from 100 to 400 (μmolm-2s-1) in a plant factory. Miraculin production per unit of energy used was highest at PPF100, although miraculin production per unit area was highest at PPF300. The commercial productivity of recombinant miraculin in transgenic tomato fruits largely depended on light conditions in the plant factory. Our trial will be useful to consider the trade-offs between the profits from production of high-value materials in plants and the costs of electricity. © 2011 Landes Bioscience.

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 CO 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 ·s ) of light intensity were set up during healing and acclimatization. Increasing light intensity significantly increased CO exchange rates during healing and acclimatization. At 95 and 90% relative humidity, the CO exchange rates at 237 μmol·m ·s light intensity were 1. 5 and 1. 8 times higher than those at 142 μmol·m ·s 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 CO 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. © 2011 Korean Society for Horticultural Science. 2 2 2 2 -2 -1 -2 -1 -2 -1

Nitrogen fertilizer application rates in intensive agricultural systems have increased dramaticallyin recent years, especially in protected vegetable production systems. This excessive use of nitrogen fertilizer has resulted in soil secondary salinity, which has become a significant environmental stress for crops such as cucumber, in the protected farmlands. It is thus necessary to illuminate how crops respond to nitrate stress. The objective of this work was to investigate the influence of three nitrate levels of 14 (CK), 56 (T-1), and 140 (T-2) mmol L on glutamine and asparagine content in the roots, stems, and leaves of cucumber (Cucumis sativus L. cv. Xintaimici) seedlings grown in hydroponic culture. The results showed that glutamine content in the roots, stems, and leaves of T-1 was a little higher than CK. In the roots, stems and leaves of T-2, glutamine content dramatically decreased over treatment course, and at 12 d decreased by 76%, 46% and 68%, respectively, with respect to CK. Asparagine content in the roots, stems, and leaves of T-1 was not significantly different from CK, whereas, in the roots, stems, and leaves of T-2 seedlings asparagine content decreased significantly. At 12 d, asparagine content in the roots, stems, and leaves of T-2 decreased by 78%, 60% and 74%, respectively, with respect to CK. This evidence indicates that the underlying mechanism of nitrate stress might be different from other abiotic ones such as salt stress and drought, which often stimulate the synthesis of amides. -1

明期の青色光強度がアントシアニン蓄積に影響するかどうかを調べたところ, 明期の青色光量を増やすとアントシアニン蓄積は促進されるが, 処理20日目までは効果が持続しなかった. 次に, LEDランプを用いて連続光条件における赤色光と青色光の割合がアントシアニン蓄積に及ぼす影響を調べた結果, アントシアニン含量は青色光の割合が高まるほど大となることが示された. そこで, アントシアニン生合成の光質応答を分子レベルで理解するために, レッドリーフレタスから単離できたアントシアニンの生合成遺伝子群について(CHS, F3H, DFR, ANS, UFGT )リアルタイムPCR法で発現解析を実施した. その結果, R100区では5遺伝子とも発現は認められなかったが, B100区とR50B50区ではCHS, F3H, DFR, ANS およびUFGT の発現が4時間までに上昇し, 48時間では低下した. F3H, DFR, ANS の発現が24時間までに上昇し, 48時間では低下したが, CHS とUFGT の発現は大きく変化しなかった. これらの結果より, レッドリーフレタスの光質に対するアントシアニンの生合成や蓄積に関する制御機構には, 赤色光と青色光の割合が密接に関係していることが明らかとなり, 特にCHS とUFGT の発現が青色光のPPFレベルに敏感に応答しているものと考えられた.

人工環境下において, 出穂後に3水準の明期(12, 16および20 h d^-1)でイネ(Oryza sativa L. cv. Nipponbare)を育成して, 成長量を調査した.<BR>イネの限界日長よりも長い明期で茎数は増加したが, 穂数は減少した. また, 地上部乾物重に対する稔実籾の乾物重の割合および稔実籾数は明期が短くなるほど増加した. これらの結果から明期が長くなるほど栄養成長である分げつの増加に光合成産物が利用され, 穂および稔実籾の形成が抑制されることが示された. 地上部乾物重は20 hで減少し, 出穂後は明期を延長しても光合成量が増加しないことが示された.<BR>以上より, 出穂後でも明期が限界日長より長くなるほど生殖成長より栄養成長が優先されること, また, 明期が短いほど稔実籾数が増加することが示された.

To study the effects of ultraviolet (UV) light on the essential oil concentration in Japanese mint (Mentha arvensis L. var. piperascens), we exposed the plants to different combinations of irradiation with a white fluorescent lamp (W), UV-A fluorescent lamp (UVA; peak wavelength, 360 nm), and UV-B fluorescent lamp (UVB; peak wavelength, 306 nm). Japanese mint transplants hydroponically grown from a rhizome in a controlled environment were used as the plant material. Young plants were cultivated in growth chambers [air temperature, 25/23°C; photosynthetic photon flux, 250μmol-m .s; CO concentration, 1,000,μmol.mol ] under the following light conditions: W, W+UVA (2.0mW.m , 315-400 nm), W+UVB (0.5 mWm , 280-350 nm), and W+UVA+UVB (2.5 mW.m , 280-400 nm). The UV irradiation period was 2 h per day during the light period (12 h). After 7 days of irradiation, the plants grown in different light conditions showed no difference in the number of leaves and leaf area. The /-menthol and limonene concentrations and the total antioxidant capacity (TAC) in the upper leaves of plants grown under the W+UVB and W+UVA+UVB conditions were significantly higher than those in the upper leaves of plants grown under the W condition. The upper leaves unfolded after the initiation of UV irradiation; further, supplemental UV-B irradiation seemed to increase the essential oil concentration and the TAC of the leaves. These results suggest that longer supplemental UV-B irradiation of Japanese mint plants may increase the yield of essential oils per plant by increasing the number of leaves that contain high concentrations of essential oils. -2 -1 -2 -2 -2 2

Genetically modified (GM) rice varieties that store up pharmaceutical proteins in seeds have recently been developed. Since the pharmaceutical protein-encoding genes of these varieties are connected with, the promoter of seed storage protein-encoding genes, the pharmaceutical protein content increases as the seed protein content increases. Rice varieties were grown in hydroponic culture at different nutrient solution concentrations at the heading time in a controlled environment. Emergence of non-productive stems was inhibited through an early reduction in the nutrient solution concentration due to accelerated translocation from the leaf blade, leaf sheath, and stem to the seed. Further, the seed storage protein, composition was altered by regulating the concentration of the nutrient solution. When the nutrient solution concentration was increased just before heading occurred, translocation to the seeds as well as the generation of non-productive stems decreased. The total protein concentration of rice seeds was not increased by the treatments of nutrient solution concentration, however, it was greater in the plants grown in the present study than in plants grown in field cultivation. Seeds in which high concentrations of total protein and seed storage protein accumulate can be produced when the nutritional content is kept constant in hydroponic culture.

The present study was performed to investigate the effects of different light periods including 8, 16 and 24 h d light in combination with two levels of light intensity, 100 and 200 ,μmol m s besides daily light integral (DLI; the product of light intensity and light period) on the growth and essential oil composition of Japanese mint plants (Mentha arvensis L. var. piperascens), a traditional aromatic and medicinal plant. The results revealed that growth was greatest in plants grown, at 24 h d ight period combined with 200/μmol m s f photosynthetic photon flux (PPF). There was no menthofuran detected in plants under either of the applied treatments. The /-menthone and /-menthol concentrations were highest in plants treated by 16 h d ight period combined with 200/μmol m s PPF. The highest content of these compounds was produced by plants grown under DLI of 8.64 mol m d and more. Results revealed that light period, exerts the most important effect on altering the growth and essential oil production of Japanese mint compared to light intensity and DLL. -1 -2 -1 -1 -2 -1 -1 2 -1 -2 -1

The influence of increased nitrate concentration-14 (control) and 140 mmol L (T)-in hydroponic culture on ammonia assimilation in cucumber (Cucumis sativus L. cv. Xintaimici) seedlings was investigated. The results showed that NH accumulation in the roots and leaves of T seedlings increased significantly, indicating that NH toxicity might be involved in nitrate stress. Under control conditions, GS and GOGAT activity were much higher in the leaves than in the roots, whereas GDH activity was much higher in the roots than in the leaves. Correlation analysis showed that NH concentration had a strong negative linear relationship with GDH activity in the roots but had a strong negative linear relationship with GS and GOGAT activity in the leaves. These results indicate that NH might be assimilated primarily via GDH reaction in the roots and via GS/GOGAT cycle in the leaves. Short-term nitrate stress resulted in the increase of GS and GOGAT activity in the roots and GDH activity in the leaves of T seedlings, indicating possible shifts in ammonia assimilation from the normal GDH pathway to GS/GOGAT pathway in the roots and from the normal GS/GOGAT pathway to the GDH pathway in the leaves under nitrate stress, but with the increase of treatment time, GS, GOGAT, and GDH activity in the roots and leaves of T seedlings decreased possibly due to low water potential and NH toxicity. © The Botanical Society of Korea 2010. -1 3 3 3 3 3

Perilla plants with red coloured leaves grown in red-enriched light treatments (i.e., red lamps alone (R), a mixture of blue and red lamps (BR), and a mixture of green and red lamps (GR)) had greater dry weight, bigger leaves, and more leaves than those grown in other treatments (i.e., blue lamps alone (B), a mixture of blue and green lamps (BG), and green lamps alone (G)). Although the concentrations of perillaldehyde and limonene in leaf tissues (mg g leaf DW) were 1.6-1.9 and 1.5-1.9 times higher, respectively, in the G treatment than in red-enriched light treatments, the contents of perillaldehyde and limonene per plant (mg/plant) were 1.8 times higher in the BR treatment than those in the G treatment. The content of anthocyanin per plant was also 4.3 times higher in the BR treatment than that in the G treatment. Therefore, within the six different combinations of fluorescent lamps used in the present study, the BR treatment was a suitable light quality for producing plants with high contents of perillaldehyde, limonene, and anthocyanin under controlled environments. © 2009 Elsevier B.V. All rights reserved. -1

The effects of three nitrate levels - 14(CK), 56(T-1), and 140 mmol L (T-2) - on growth and photosynthetic capacity of cucumber (Cucumis sativus L. cv. Xintaimici) seedlings grown in hydroponic culture were investigated. The results showed that at 12 d after treatment plant height, stem diameter, leaf area, and leaf number of cucumber seedlings were stimulated by 56 mmol L nitrate, whereas were inhibited significantly by 140 mmol L nitrate compared with CK. Short-term stimulation in photosynthetic rate occurred under T-1 treatment, and then recovered to the level of CK. Photosynthetic rate of T-2 seedlings significantly decreased over treatment course with respect to CK. Photosynthetic pigment content of T-1 and T-2 increased during the first 2 d, and gradually recovered to the level of CK thereafter. Chlorophyll a/b and carotenoids/chlorophyll of T-1 had no significant difference from CK during treatment period. During the first 4 d, there was no significant difference in chlorophyll a/b and carotenoids/chlorophyll between T-2 and CK. After 4 d, chlorophyll a/b of T-2 increased gradually, whereas carotenoids/chlorophyll decreased. Actual PSII efficiency (ΦPSII) and photochemical quenching (qP) of T-1 had no significant difference from CK, and non-photochemical quenching (qN) was a little higher than CK after 2 d. During the first 2 d, there was little difference in ΦPSII and qP between T-2 and CK. After 2 d, both ΦPSII and qP of T-2 decreased to a great extend. A significant increase in qN of T-2 occurred over treatment course. With respect to CK, Hill reaction activity of T-1 slightly decreased, and T-2 treatment resulted in a significant decrease of Hill reaction activity. This evidence indicates that high-level nitrate stress may reduce photosynthesis through its effects not only on stomatal conductance but on the photosynthetic apparatus. -1 -1 -1

We studied the effects of light conditions and air temperature on the growth of the everbearing strawberry (Fragaria × ananassa Duch. cv. 'HS138') during the vegetative stage in order to optimize the environmental conditions required for plant growth. We conducted 4 treatments with continuous lighting at 2 light intensities (225 and 337.5 μmol·m s ) and 2 air temperatures (25 or 20°C) and 2 treatments with a 16-h light period and a light intensity of 337.5 μmol·m ·s (light/dark, 25/25 or 25/20°C, respectively). The daily light integrals (DLIs) of these 6 treatments were classified into 19.4 (low) or 29.2 (high) mol·m ·d . All plants were cultivated hydroponically for 20 days after transplanting. Under the same DLI condition, variations in the light period were not observed to have any effect, and dry matter accumulation in the plants without roots was higher at 25°C than at 20°C. Under the same air temperature condition, dry matter accumulation in the plants was 1.4-1.5 times greater at a high DLI than at a low DLI. In conclusion, within the range of this experiment, the optimum growth condition for the everbearing strawberry during the vegetative stage was a DLI of 29.2 mol·m ·d and a temperature of 25°C. -2· -1 -2 -1 -2 -1 -2 -1

To achieve the mass production of pharmaceutical proteins in genetically modified (GM) strawberry (Fragaria × ananassa Duch. cv. 'HS138'), a continuous supply of a large number of uniform seedlings is required. We modified the micropropagation method which is suitable for subsequent hydroponic cultivation in a closed plant production system with artificial lighting. In this study, we conducted 6 treatments comprising 2 in vitro culture methods (PM: photomixotrophic culture or PA: photoautotrophic culture) during the rooting stage for 3 weeks and 3 light qualities (white, red and blue) for 4 weeks after transplanting to the ex vitro hydroponic system. The PM plantlets without roots were cultured on agar during the rooting stage, and their roots were washed to remove the agar before transplanting them to the hydroponic system. In contrast, the PA plantlets were cultured on a fibre rod as the supporting medium, which was the same medium as that used in the hydroponic stage. At the end of the rooting stage, the number of leaves, leaf area and dry matter were significantly higher in the PA plantlets than in the PM plantlets. During the hydroponic cultivation stage, the dry matter of seedlings was significantly higher under white and red light conditions than under blue light condition, irrespective of the culture method during the rooting stage. These results suggest that a combination of the PA culture methods during the rooting stage and white or red light condition after the transplanting can improve the efficiency of the propagation method used for GM strawberry production.

Japanese mint (Mentha arvensis L.) plants were grown under three different treatments of light quality (blue, green and red light) provided by colored fluorescent lamps. Leaf dry weight of the plants was 1.3 and 1.2 times higher in the red-light treatment than in blue- and green-light treatments, respectively. The content of l-menthol (mg/plant), which is the main component of the essential oil in the plants, was 1.4 times higher in the red-light treatment than in the blue- and green-light treatments, while the /-menthol concentration (mg g leaf DW) was not significantly different among the treatments. Our results suggest that red light is beneficial for producing Japanese mint plants with high essential oil contents under controlled environments with artificial light. -1

Qing-geng-cai (Brassica chinensis L., cv. Seitei) and spinach (Spinacia oleracea L., cv. Sunlight) seedlings were grown in plug trays at 3 planting densities and 2 air current speeds either in a closed transplant production system (CTPS) or in a greenhouse in which the air current speed was not controlled. The growth parameters such as dry mass, plant height, and leaf area; uniformity of qing-geng-cai; and growth of spinach seedlings decreased with the increase in planting density in the CTPS. At higher air current speeds, the growth of the qing-geng-cai seedlings decreased. However, the growth of the spinach seedlings was not affected by the air current speed. Based on these results, the differences in the extent of mutual shading and space in the seedling populations caused by the differences in canopy height and leaf angle appear to be responsible for differences in. the effect of air current speed on the growth of seedlings of each species. The growth and uniformity of qing-geng-cai and the growth of spinach seedlings were greater in the CTPS than in the greenhouse. Based on the abovementioned results, we conclude that growth in the CTPS facilitates denser seedling production and shorter production period in comparison to that in the greenhouse.

Perilla (Perilla frutescens Britt.) plants with red colored leaves were grown under ultraviolet-B radiation (UV-B) of 0. 0.21, and 0.88 W m at a constant photosynthetic photon flux of 200 μmol m s provided by UV-B and fluorescent lamps, and an irradiation period of 16 h d . The leaf dry weight and leaf area of the plants were 19-23% and 14-19% smaller, and the concentration of anthocyanin (mg g leaf DW) was 17-18% lower with UV-B than without, respectively. The concentrations of perillaldehyde and limonene (mg g leaf DW), and the number of true leaves were not affected by the UV-B. The UV-B suppressed the growth and anthocyanin production, but had no effect on the concentrations of essential oil components in leaves of the plants. -2 -2 -1 -1 -1 -1

Hypericin and pseudohypericin are the major bioactive constituents of floral parts of Hypericum perforatum L., mainly used for the treatment of neurological disorders and depression. The principle objective of the current study was to evaluate the effect of blue, blue and red mixed, and red light on flowering time and concentration of hypericin, pseudohypericin and hyperforin in the floral tissues of H. perforatum plants. The results revealed that red light promoted flowering and production of the three major medicinal components, indicating the influence of spectral characteristics of light on flowering of H. perforatum plants. Spectral quality of light was found to be an important factor in controlling the flowering of H. perforatum plants.

It has been known that diapause is not induced in populations of the two-spotted spider mite, Tetranychus urticae, under continuous darkness (DD). When the light intensity was changed under LD 8:16 at 18°C, the threshold intensity for blue light (475 nm) to induce 50% of diapause was below 50 mW/m ; and the blue light was most effective in photoperiodic induction of diapause. The threshold intensities for green (572 nm) and orange (612 nm) light were 50-500 and 500-2,500 mW/m , respectively. T. urticae showed no sensitivity to red light (658 nm) even at 2,500 mW/m intensity. Low diapause incidence under long wavelengths was probably due to the absence of photoreception by photoreceptor pigments for photoperiodic time measurement, or for circadian entrainment required for photoperiodic induction. 2 2 2

閉鎖型システムにおいて, 栽植密度および気流速度を変えてトマト実生苗を育成して, 成長量およびその均一性を調査した. また, 温室にて育成した苗との比較も行った.<BR>閉鎖型システムにおいて栽植密度が高いほど苗は徒長し, 乾物重や生体重が減少し, 成長量の均一性は低くなった. また, 気流速度が高い方が乾物重や生体重が増大した. 徒長, および成長量の均一性は気流速度による有意な影響を受けなかった. これらの結果から, 気流速度を高めれば, 栽植密度が高くとも, 苗を徒長させず, かつ成長量の均一性を保持したまま生育の促進が行えることが示された.<BR>閉鎖型システムの苗は温室よりも栽植密度を高くしても徒長せず, 乾物重が大きく, 成長量が均一な品質の高い苗であることが示された.<BR>以上から, 閉鎖型システムを用いて気流速度を調節することで, 温室などの育苗施設よりも, 更なる密植育苗もしくは育苗期間の短縮ができることが示された.