彦坂 晶子

The effect of the ratio of red and blue light on fruit biomass radiation-use efficiency (FBRUE) in dwarf tomatoes has not been well studied. Additionally, whether white light offers a greater advantage in improving radiation-use efficiency (RUE) and FBRUE over red and blue light under LED light remains unknown. In this study, two dwarf tomato cultivars (‘Micro-Tom’ and ‘Rejina’) were cultivated in three red-blue light treatments (monochromatic red light, red/blue light ratio = 9, and red/blue light ratio = 3) and a white light treatment at the same photosynthetic photon flux density of 300 μmol m^–2 s^–1. The results evidently demonstrated that the red and blue light had an effect on FBRUE by affecting RUE rather than the fraction of dry mass partitioned into fruits (F_fruits). The monochromatic red light increased specific leaf area, reflectance, and transmittance of leaves but decreased the absorptance and photosynthetic rate, ultimately resulting in the lowest RUE, which induced the lowest FBRUE among all treatments. A higher proportion of blue light (up to 25%) led to a higher photosynthetic rate, resulting in a higher RUE and FBRUE in the three red-blue light treatments. Compared with red and blue light, white light increased RUE by 0.09–0.38 g mol⁻¹ and FBRUE by 0.14–0.25 g mol⁻¹. Moreover, white light improved the F_fruits in ‘Rejina’ and Brix of fruits in ‘Micro-Tom’ and both effects were cultivar-specific. In conclusion, white light may have greater potential than mixed red and blue light for enhancing the dwarf tomato FBRUE during their reproductive growth stage.

We propose a platform called “LCA-Multidimensional Map (LAMP)” to support companies and individuals aiming for CO2 zero emissions (CZEs) by efficiently conducting life cycle assessments (LCAs) of their products and activities, collecting information necessary for CZEs, and developing CO2 reduction plans. LAMP is a multidimensional platform that supports the development of CZEs targets in cyberspace without temporal or spatial constraints. Using this software, LCAs can be conducted using existing database groups constructed in two and three dimensions in various sectors as well as data groups with temporal information, such as evolving and continuous records, and spatial information in a cross-sectional manner. Furthermore, based on the LCA results, CO2-emission-reduction plans can be formulated (extraction of alternatives), and their effectiveness can be confirmed through LCA again. As an example of how to use LAMP, we introduce the characteristics of LCA in horticulture, the second-largest source of CO2 emissions after livestock in the agricultural sector, along with examples of alternative plans for greenhouses, collaboration plans with other sectors, and basic methods for promoting CZEs in horticulture. Although this concept needs to be tested and validated in the future, it might encourage individuals or companies to cooperate in LAMP development or inspire them to advocate for more progressive ideas.

type:text [ABSTRACT] In 2021, we started the new project for viticulture by plant factory with artificial light. However, there are various technical issues, which specified to the woody species, should be overcome for the achievement of viticulture in plant factory with artificial light. Here, we first review the current practice and several technologies for viticulture in plant factories with sunlight and find out the technical issues that need to be overcome to establish viticulture by plant factory with artificial light. Next, we discussed １) the state-of-the-art knowledge about plant monitoring using remote sensing, and ２) the technologies applied to various horticultural crops in plant factory with artificial light practical. These relevant research observations indicate the future breakthrough technologies, which we should develop throughout our new project, for viticulture in plant factory with artificial light. [抄録] 人工光植物工場を活用したブドウ生産の実現には，木本植物である果樹に特有の技術的に検討すべき課題が多く存在する．そこで本稿では，まず太陽光利用を含めた植物工場におけるブドウを中心とした果樹生産の現状を俯瞰することで，人工光植物工場でのブドウ生産の実現に向けてブレークスルーすべき技術的な課題を提示する．次にリモートセンシングを利用した植物モニタリングの最先端の知見を解説するとともに，様々な園芸作物における人工光植物工場における技術を議論することで，2021年度園芸フロンティア研究プロジェクトにおいて推進中の「植物工場でのブドウ栽培を実現する先進的果樹栽培技術の確立」において開発を目指す技術の一端について紹介をする．

This study aimed to analyze the effects of photosynthetic photon flux density (PPFD) on fruit biomass radiation-use efficiency (FBRUE) of the dwarf tomato cultivar ‘Micro-Tom’ and to determine the suitable PPFD for enhancing the FBRUE under LED light at the reproductive growth stage. We performed four PPFD treatments under white LED light: 200, 300, 500, and 700 μmol m⁻² s⁻¹. The results demonstrated that a higher PPFD led to higher fresh and dry weights of the plants and lowered specific leaf areas. FBRUE and radiation-use efficiency (RUE) were the highest under 300 μmol m⁻² s⁻¹. FBRUE decreased by 37.7% because RUE decreased by 25% and the fraction of dry mass portioned to fruits decreased by 16.9% when PPFD increased from 300 to 700 μmol m⁻² s⁻¹. Higher PPFD (500 and 700 μmol m⁻² s⁻¹) led to lower RUE owing to lower light absorptance, photosynthetic quantum yield, and photosynthetic capacity of the leaves. High source strength and low fruit sink strength at the late reproductive growth stage led to a low fraction of dry mass portioned to fruits. In conclusion, 300 µmol m⁻² s⁻¹ PPFD is recommended for ‘Micro-Tom’ cultivation to improve the FBRUE at the reproductive growth stage.

Abstract Ophiorrhiza pumila is a medicinal plant that grows in subtropical forests and produces camptothecin (CPT). To determine an optimal harvest time of O. pumila in a plant factory with artificial light (PFAL), we investigated the CPT distribution in each organ and at the developmental stage and estimated the annual CPT production. For this study, the O. pumila plants were grown in controlled environments (16 h light period, photosynthetic photon flux density of 100 μmol m⁻² s⁻¹ under white light-emitting diode lamps, air temperature of 28 °C, relative humidity of 80%, and CO₂ concentration of 1000 μmol mol⁻¹). First, the stem, root, and seed pod had higher CPT contents than the leaves, flower, and ovary. The optimal harvest time of O. pumila in a PFAL was 63 days after transplanting (DAT), because the CPT content in the whole organs was the highest at the seed-ripening stage. Second, based on these results, the estimated annual CPT production of O. pumila cultivated in a PFAL was 380 mg m⁻² y⁻¹ (63 DAT). This value was 4.3 times greater than the annual CPT production by Camptotheca acuminata in a greenhouse. We concluded that the CPT production by O. pumila in a PFAL throughout the year has many advantages, although the demand for electrical energy was high compared to that of Camptotheca acuminata in a greenhouse.

The demand for high-quality tomatoes is increasing; however, their production requires skillful techniques. To develop an automated irrigation method for producing high-quality tomatoes in a greenhouse, we used an image-based irrigation system to study how a diurnal periodic cycle of wilting–partial recovery irrigation affects growth, yield, and fruit quality. Three irrigation treatments were performed: a control with sufficient irrigation and two water stress treatments (moderate and severe wilting–partial recovery treatments; MPR and SPR, respectively). The mean daily maximum wilting ratios for MPR and SPR were 8.1% and 13.2% at wilting-level setpoints of 7% and 14%, respectively. The total irrigation amounts in MPR and SPR were 75% and 59% of that in the control, respectively. The corresponding yields in MPR and SPR were 76% and 56% of that in the control, respectively. The Brix and acidity of fruits in MPR and SPR were 15% and 10% and 34% and 24% higher, respectively, than those in the control at the end of the experiment. Plant growth decreased with increasing water stress levels. Plant length, leaf area, and the number of leaves were more sensitive to water stress than other growth parameters. SPR could be an effective irrigation method to improve fruit quality, even at high-air-temperature periods in summer.

Secondary metabolite biosynthetic pathways are influenced by environmental stressors, such as light, temperature, atmospheric gases, and air movement. To determine the dynamics of secondary metabolite biosynthesis under environmental stress in a plant factory with artificial light and to identify valuable bioactive compounds, a transcriptome analysis was performed using vegetative-stage Brassica napus L. as a model of Brassica leafy vegetables. At 18 days after sowing, plants were exposed to one of two environmental stressors for 5 days: UV-B irradiation (0.6 W m-2) and ozone (200 ppb). The growth condition was as follows: air temperature, 25/20°C (light/dark); relative humidity, 70%; light period, 16 h; photosynthetic photon flux density, 200 µmol m-2 s-1, using a white fluorescent lamp; and CO2 concentration, 1,000 ppm. The 2nd and 3rd leaves of unexposed (control) and stressor-exposed plants were sampled for both transcriptome analysis of secondary metabolite biosynthetic pathways via DNA microarrays and quantitative gene expression analysis via real-time RT-PCR, and to measure the concentration of key phytochemicals. Both the phenylpropanoid and flavonoid biosynthetic pathways were activated in the UV-treated plants, and the phenylpropanoid biosynthetic pathway was activated in the ozone-exposed plants. Consequently, the total phenolic and total flavonoid concentrations increased under these conditions. Our results show that exposure to these environmental stressors in a plant factory for a few days prior to harvest helps to effectively manipulate the accumulation of phytochemicals for intended targeted applications.

The leaf of red perilla is used as an herbal medicine in Japan. For efficient production of red perilla in a plant factory with artificial light, it is necessary to investigate the fundamental behaviour in bioactive compounds, such as perillaldehyde (PA) and anthocyanin (ANT). Red perilla seeds were cultivated in a controlled-environmental chamber for 30 days post-germination. On day 30, the plants were grown under various levels of photosynthetic photon flux density (PPFD: 50, 100, 200, and 400 µmol m-2 s-1), provided with white fluorescent lamps in a controlled environment. After 35 days, PA and ANT levels at each different leaf position were measured. We also measured PA and ANT concentration at the same leaf position every 3 days, at 200 µmol m-2 s-1 PPFD, to investigate the changes at different leaf ages. A gradual decrease in PA concentration from the upper leaf position to the lower leaf position at all PPFD levels was observed, while the ANT concentration was almost constant regardless of leaf position. The concentration of PA was not significantly different among various PPFD levels. ANT concentration differed significantly only between 50 and 200 µmol m-2 s-1 PPFD. PA concentration gradually decreased from 3 days to 15 days after unfolding. In contrast, the ANT concentration was almost constant regardless of leaf age. Our results suggest that harvesting upper red perilla leaves is suitable for efficient production of bioactive compounds in red perilla in a plant factory.

In this study, we developed an automatic irrigation method using an image-based irrigation system for high-quality tomato production in a greenhouse by investigating effects of a diurnal periodic cycle of irrigation on the photosynthesis, growth, yield, and fruit quality of tomatoes. The diurnal periodic cycle in a moderate wilting–full recovery treatment (MR) with a medium threshold value was more frequent than that in a severe wilting–full recovery treatment (SR) with a high threshold value. Mean daily maximum wilting ratios for MR and SR were 7.2% and 11.3%, respectively, when wilting ratios were set to threshold values of 7% and 14%, respectively. Total irrigation amounts in MR and SR were similar and lower than that in the untreated control. Net photosynthetic rate decreased under water stress, with values in MR being higher than that in SR, and recovered rapidly to more than 90% of its maximum value following irrigation. Plant growth and fruit yield per plant in MR and SR were lower than that in the control. Water stress treatment could improve fruit quality when it commenced at the anthesis stage or early fruit development stage. Total irrigation amount was a more important parameter than the threshold value for controlling the growth, yield, and fruit quality of tomatoes.

Dwarf tomatoes are advantageous when cultivated in a plant factory with artificial light because they can grow well in a small volume. However, few studies have been reported on cultivation in a controlled environment for improving productivity. We performed two experiments to investigate the effects of photosynthetic photon flux density (PPFD; 300, 500, and 700 μmol m-2 s-1) with white light and light quality (white, R3B1 (red:blue = 3:1), and R9B1) with a PPFD of 300 μmol m-2 s-1 on plant growth and radiation-use efficiency (RUE) of a dwarf tomato cultivar ('Micro-Tom') at the vegetative growth stage. The results clearly demonstrated that higher PPFD leads to higher dry mass and lower specific leaf area, but it does not affect the stem length. Furthermore, high PPFD increased the photosynthetic rate (Pn) of individual leaves but decreased RUE. A higher blue light proportion inhibited dry mass production with the same intercepted light because the leaves under high blue light proportion had low Pn and photosynthetic light-use efficiency. In conclusion, 300 μmol m-2 s-1 PPFD and R9B1 are the recommended proper PPFD and light quality, respectively, for 'Micro-Tom' cultivation at the vegetative growth stage to increase the RUE.

In Japan, red perilla leaves are used in the food and coloring industries, as well as in crude medicine. Perilla leaves contain a high concentration of phytochemicals such as perillaldehyde (PA) and rosmarinic acid (RA). The effects of UV-B radiation intensity (0.05-0.2 W m-2, UV-BBE: 0.041-0.083 W m-2), duration (3 or 6 h), and irradiation method (continuous or intermittent) for artificial nocturnal lighting using UV-B fluorescent lamps were evaluated on growth, flowering, and leaf phytochemical concentration in greenhouse-grown perilla. Under continuous UV-B irradiation at 0.1 W m-2 for 3 or 6 h, leaf color changed from red to green and leaf fresh weight decreased, compared with the control treatment. No leaf color change was observed under the 3-h treatment with UV-B radiation at 0.05 W m-2, wherein leaf fresh weight was similar to that of the control. Furthermore, RA concentration under continuous UV-B irradiation at 0.05 W m-2 for 3 h increased two-fold compared to that under control treatment, while PA concentration was not affected by UV-B irradiation. Thus, our data showed that continuous UV-B irradiation at 0.05 W m-2 for 3 h could effectively produce RA-rich perilla leaves without reducing in phenotypic quality or productivity. However, a 6-h intermittent illumination inhibited flowering without altering phytochemical concentration.

Plant genomes remain highly fragmented and are often characterized by hundreds to thousands of assembly gaps. Here, we report chromosome-level reference and phased genome assembly of Ophiorrhiza pumila, a camptothecin-producing medicinal plant, through an ordered multi-scaffolding and experimental validation approach. With 21 assembly gaps and a contig N50 of 18.49 Mb, Ophiorrhiza genome is one of the most complete plant genomes assembled to date. We also report 273 nitrogen-containing metabolites, including diverse monoterpene indole alkaloids (MIAs). A comparative genomics approach identifies strictosidine biogenesis as the origin of MIA evolution. The emergence of strictosidine biosynthesis-catalyzing enzymes precede downstream enzymes' evolution post γ whole-genome triplication, which occurred approximately 110 Mya in O. pumila, and before the whole-genome duplication in Camptotheca acuminata identified here. Combining comparative genome analysis, multi-omics analysis, and metabolic gene-cluster analysis, we propose a working model for MIA evolution, and a pangenome for MIA biosynthesis, which will help in establishing a sustainable supply of camptothecin.

<p>Sweet basil (Ocimum basilicum L.), one of the most widely consumed herbs globally, is used in raw or processed food, and for aromatic essential oils. We investigated the effects of photosynthetic photon flux density (PPFD; 150, 225, and 300 μmol·m⁻²·s⁻¹, herein, referred to as P150, P225, and P300) and red to blue light ratios (R/B ratio) (R:B = 1:4, 1:1, and 4:1, herein, referred to as R/B 0.25, 1.0, and 4.0) with a 16 h light period on the leaf shape and concentrations of functional and aromatic compounds in basil. Total leaf dry weight and leaf mass per area increased with increasing PPFD and R/B ratio. Total leaf area tended to increase with increasing R/B ratio at the same PPFD. Although the highest growth was noted when R/B was 4.0 at P300, the leaves showed ruggedness and curling. β-Carotene concentration based on the leaf dry weight and leaf area at the fourth node increased with decreasing R/B ratio, regardless of PPFD. Concentrations of aromatic compounds (eugenol and linalool) based on dry weight were significantly higher at P150 than at other PPFDs and in treatments with greater amounts of red light. These results suggest that basil growth, appearance, and functional and aromatic compound concentrations can be adjusted as needed by manipulating the PPFD and R/B ratio, although R/B 4.0 at P300 caused malformed leaves.</p>

Phytochemicals derived from secondary metabolites that are accumulated in plant leaves are used as functional foods, pharmaceutical materials, and raw materials for industry. Secondary metabolite biosynthesis pathways are influenced by environmental stresses including light, temperature, atmospheric gases, and nutrient solution. In this study, we determined the environment conditions that would increase or decrease the content of phytochemical compounds under totally controlled environments such as plant factories. We used vegetative-stage Brassica napus L. and Nicotiana benthamiana as model plants for Brassica leaf vegetables and for the production of pharmaceutical and industrial raw materials, respectively. At 18-25 days after sowing, plants were exposed to four environmental stress factors, alone or in combination for 3-6 days: UV-B irradiation (0-1.0 W m-2), low nutrient solution temperature (5-15°C), and ozone gas exposure (100-400 ppb). For plants either exposed and not exposed (control) to stress, the third and fourth leaves were sampled for transcriptome analysis of secondary metabolite pathways using DNA microarrays, quantitative gene expression analysis using real-time RT-PCR, and measurement of the concentration of key phytochemicals using HPLC. Ascorbic acid, isoprenoid, and flavonoid pathways were activated in N. benthamiana upon exposure to UV irradiation or a combination of UV and low solution temperature. Low solution temperature increased expression of some alkaloid pathway genes. In B. napus, the phenylpropanoid and flavonoid pathways were activated following exposure to UV irradiation or ozone gas. Consequently, antioxidant capacity and total phenolic content increased under these conditions. However, the carotenoid pathway was not activated in either of the plant species following UV or ozone exposure. Thus, exposure to these environment stresses can be used to manipulate phytochemical compound accumulation targeted to the intended use.

For the production of high-quality tomato fruit (i.e., fruit with high sugar content), it is necessary to apply water absorption stress through irrigation restriction. However, excessive deficit irrigation (DI) often leads to severe growth inhibition and irreversible wilting; therefore, stable production of high-quality tomato requires frequent observation and irrigation control by growers, making the process labor intensive. In the present study, we aimed to develop an automatic system of water-stress control by image analysis. First, we subjected tomato plants to DI treatment manually in a summer greenhouse and automatically captured tomato canopy images using an overhead camera every 1 min. Using an original software, we determined the projected leaf area (PLA) from the canopy images under various natural light conditions and calculated the wilting ratio (W; percentage of PLA per non-wilting PLA in the early morning). During this period, we randomly measured the leaf water potential (LWP) destructively at various wilting stages. The results revealed a significant negative correlation between the W (0-25%) and LWP (-0.2 to -1.5 MPa). According to the manual irrigation timing, the appropriate range of the setting value of W and LWP for irrigation was 15 to 20% and -1.02 to -1.21 MPa, respectively. Next, we installed this software into an irrigation system and controlled the W under DI treatment, as a measure of water-stress level of tomato canopy, automatically for a few months. The Brix percentage of tomato under DI was higher (8.0%) than that of tomato under sufficient irrigation (control) (5.5%) and the total yield under DI was 40% that of the control. Overall, appropriate LWP for other canopies or in other greenhouses can be adjusted using the W calculated from photo-images. In conclusion, we developed a control system of plant water-stress level by photo-image analysis for stable high-quality tomato production.

The medicinal plant, Ophiorrhiza pumila, naturally grows on the floors of humid inland forests in subtropical areas. It accumulates camptothecin (CPT), which is used as an anti-tumor agent, in all organs. We investigated the optimal hydroponic root-zone environments for growth and CPT accumulation in O. pumila in a plant factory. In experiment 1, to determine the appropriate nutrient solution concentration (NSC), O. pumila was cultivated using four concentrations (0.125, 0.25, 0.5, and 1.0 times) of a commercial solution for 63 days after the start of treatment (DAT). The electrical conductivity of these NSCs was 0.6, 0.9, 1.5, and 2.7 dS m-1, respectively. The total dry weights at 0.25 and 0.5 NSCs were higher than those at the other two NSCs. CPT content at 0.25 NSC was significantly higher than those at other NSCs. In experiment 2, to investigate an appropriate nutrient solution temperature (NST), O. pumila was cultivated at four NSTs (10, 20, 26, and 35 °C, named as T10, T20, T26, and T36, respectively) for 35 DAT. The growth and CPT content at T20 was the highest among the treatments. Therefore, root-zone environments of 0.25 NSC and 20 °C of NST produced the best growth and CPT accumulation in O. pumila.

In a plant factory with artificial light, accumulation of bioactive compounds can be enhanced via precise environmental control. Light is essential for growth and development, and for the production of bioactive compounds in plants. Ultraviolet (UV) light stimulates bioactive compound biosynthesis in plants including antioxidants. We developed a new and economical UV-rich fluorescent lamp (UV-FL), with the ability to adjust the ratio of UV-A and UV-B. The objective of this study was to determine the effect of UV light on the accumulation of bioactive compounds in red leaf lettuce. Red leaf lettuce plants were grown in a plant factory with normal growing conditions under white light as light source (23/20°C, 70% RH, 16 h light period, PPFD 150 μmol m-2 s-1, 1,000 ppm CO2) for 23 days. The plants were subjected to UV light under white light (low, middle, and high; 0.3, 0.6, and 0.9 W m-2) for 3 days before harvest. Fresh and dry weights of shoot, leaf area, total chlorophyll, total phenolic concentration, and ORAC for antioxidant activity were measured before and after the UV treatments. Middle and high UV treatments resulted in negative effects on the growth characteristics such as shoot fresh and dry weight, and leaf area. However, low UV treatment was not significantly different from the control for shoot dry weight. Total chlorophyll was higher in low and middle UV treatments than the high UV treatment and the control. In contrast, total phenolic concentration and ORAC value of lettuce plants grown under UV treatments were significantly higher than that of the control. This study suggests that short-term UV irradiation using economical UV-FL lamp before harvest was effective in improving the vegetable quality.

Red perilla (Perilla frutescens) is used as food, crude drug, and cosmetics. The major bioactive compounds of red perilla are perillaldehyde, rosmarinic acid, luteolin, and anthocyanin. In this study, we evaluated the effects of UV light on the accumulation of the bioactive compounds and gene expression of related enzymes under controlled environments. Red perilla was cultivated in a controlled-environment room for 35-42 days after germination. The growing condition was air temperature 25/20°C (light/dark), R.H. 70%, light period 16 h, 200 µmol m-2 s-1 of PPFD and CO2 conc. 1000 ppm. The plants were exposed to UV-B light of 1.0 W m-2 for 3 days. The concentrations of perillaldehyde (PA), rosmarinic acid (RA), and anthocyanin (ANT) were measured by HPLC. The expression levels of genes related to RA and ANT synthesis were analyzed by RT-RT-PCR. The PA and RA concentrations at 3 days after the start of UV irradiation increased compared to that of the control. The expression of phenylalanine ammonia-lyase (PAL) and thyrosin aminotransferase (TAT), key genes of the phenylpropanoid pathway for RA synthesis, was higher at 48-72 h in the UV treated plants than those in the control after the start of UV irradiation. The RA concentration increased as a result of antioxidant response to the ROS generated by exposure to UV light. The expression of five genes in the flavonoid pathway increased 24 h after the start of UV irradiation. Total ORAC values of the plants under UV treatment was higher than in the control. Based on the results, we conclude that a short period of UV-B irradiation stimulates the phenylpropanoid pathway for the biosynthesis of RA, and drives the flavonoid pathway for production of ANT, in addition to enhancing the production of other antioxidant compounds.

Ophiorrhiza pumila is a medicinal plant distributed on the floors of humid inland forests in subtropical areas and accumulates camptothecin (CPT) in whole plant organs. To elucidate the proper light and air temperature conditions for plant growth and CPT yield, we conducted two experiments under controlled environments. In experiment 1, we measured the net photosynthetic rate (P_n) and transpiration rate (E) of the whole plant O. pumila using an open-type assimilation chamber under different photosynthetic photon flux densities (PPFDs) and air temperatures. The result showed that the combination of an air temperature of 28 °C and a PPFD of 100 μmol m^-2 s^-1 was a good condition for photosynthesis and transpiration. In experiment 2, O. pumila was cultivated for 35 days under three PPFDs and three light periods at an air temperature of 28 °C. At a PPFD of 100 μmol m^-2 s^-1 and a light period of 16 h, growth was accelerated by the generating the lateral shoots and branches, and total CPT content per plant was the highest among these treatments. The present study revealed that the proper PPFD and light period conditions could enhance growth and CPT accumulation of O. pumila.

<p>Transgenic ever-bearing strawberry (Fragaria×ananassa Duch. 'HS 138') was cultivated in a closed plant production system to produce functional proteins that can enhance human immune functions. We investigated the effects of air temperature before harvest on fruit growth and the concentration of human adiponectin (hAdi) at harvest in transgenic strawberry. During the different stages of maturity (mature white and immature green stages), hAdi-expressing plants were exposed to four air temperature treatments (15, 20, 25, and 30°C) under 24-h illumination provided by fluorescent lamps. Fruits were harvested at the mature red stage. The number of days to the mature red stage decreased with increasing air temperature, being the least at 30°C. Fruit total soluble protein (TSP) concentration increased with decreasing air temperature, particularly at 15°C, whereas fruit hAdi concentration tended to be higher under the 30°C treatment than under any other of the temperature treatments. There was no significant relationship between fruit fresh weight at harvest time and hAdi concentration within treatments, nor between the number of days to harvest and hAdi or TSP concentration. Although there were no significant differences in fruit hAdi content among treatments, hAdi production rate was the highest at 30°C because of the shortest duration to harvest. These results indicate that a higher air temperature promoted fruit maturation and accelerated the production of functional hAdi proteins in the fruit. For hAdi-expressing strawberry plants, exposure to 30°C may reduce energy consumption (lighting and air conditioning) for functional protein production under controlled environments.</p>

Most strawberry fruits in Japan are produced under forced-production culture, using June-bearing cultivars. Strawberry plants are transplanted in a heated greenhouse in autumn and the normal harvest period is from late November to June. Insufficient solar radiation for fruit loading during the winter sometimes causes a decline in growth and yield. Therefore, we investigated the effects of supplementing natural light with artificial lights using light-emitting diodes (LEDs). The experiment was conducted in a greenhouse (2400 m2 in area) located in Yamamoto town, Miyagi prefecture, Japan (37.961°N, 140.877°E). Strawberry plants were transplanted in an elevated bed. We ran two experiments: experiment 1 was on light quality [photosynthetic photon flux density (PPFD) ratio of red light to blue light], while experiment 2 examined various lamp positions relative to the plants. In experiment 1, strawberry plants were exposed to three different qualities of light (red-to-blue ratios of 2:1, 3:1, and 4:1) with LED lamps (peak blue wavelength 450 nm, peak red wavelength 660 nm, SFL 120 BR-ERx). In experiment 2, LED lamps of two light qualities (red-to-blue ratios of 3:1 and 4:1) were installed in three different positions (above, in the middle, and at the bottom of treatment containers). Yields increased in almost all supplementary-light treatments relative to controls in both experiments. In experiment 1, the yield was higher when the PPFD ratio was 3:1 or 4:1 than when it was when 2:1. In experiment 2, strawberry yield increased by about 10% relative to the control, but no significant difference was observed among light positions or light quality. In addition, no increase in total dry weight was observed as a result of supplemental lighting, but the fruit distribution ratio (fruit dry matter/total dry matter) increased. It is possible that morphological changes caused by supplemental LED lighting led to the increase in fruit yield.

薬用アカジソの最大展開までの個葉の成長に伴う生理活性物質濃度の経日変化ならびに，その期間における10 ℃での低培養液温処理の影響を調査した．10 ℃での低培養液温処理で少なくとも6日までは地上部の生育は抑制されないことが示された．個葉の主要な生理活性物質の濃度は，展開開始後経日的に変動し，成分の種類によってその挙動は異なった．また，低培養液温処理により主な生理活性物質の濃度はControlより高くなり，その時期は生理活性物質により異なった．

Tomato (Solanum lycopersicum) is a model crop for studying development regulation and ripening in flesh fruits and vegetables. Supplementary light to maintain the optimal light environment can lead to the stable growth of tomatoes in greenhouses and areas without sufficient daily light integral. Technological advances in genome-wide molecular phenotyping have dramatically enhanced our understanding of metabolic shifts in the plant metabolism across tomato fruit development. However, comprehensive metabolic and transcriptional behaviors along the developmental process under supplementary light provided by light-emitting diodes (LEDs) remain to be fully elucidated. We present integrative omic approaches to identify the impact on the metabolism of a single tomato plant leaf exposed to monochromatic red LEDs of different intensities during the fruit development stage. Our special light delivery system, the "simplified source-sink model," involves the exposure of a single leaf below the second truss to red LED light of different intensities. We evaluated fruit-size- and fruit-shape variations elicited by different light intensities. Our findings suggest that more than high-light treatment (500 μmol m-2 s-1) with the red LED light is required to accelerate fruit growth for 2 weeks after anthesis. To investigate transcriptomic and metabolomic changes in leaf- and fruit samples we used microarray-, RNA sequencing-, and gas chromatography-mass spectrometry techniques. We found that metabolic shifts in the carbohydrate metabolism and in several key pathways contributed to fruit development, including ripening and cell-wall modification. Our findings suggest that the proposed workflow aids in the identification of key metabolites in the central metabolism that respond to monochromatic red-LED treatment and contribute to increase the fruit size of tomato plants. This study expands our understanding of systems-level responses mediated by low-, appropriate-, and high levels of red light irradiation in the fruit growth of tomato plants.

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.

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 ^&minus;2 d ^&minus;1 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.

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．

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.

It has been reported that parthenocarpic cucumbers with many female flowers and heavy fruit load often show fruit abortion and reduced fruit yield. To achieve the stable fruit production, it is necessary to elucidate the mechanism involved in fruit abortion in cucumbers via fruit load and endogenous plant hormones. In Exp. 1, the effects of exogenous plant growth regulators (PGRs) on yield and fruit growth were examined in a gynoecious, parthenocarpic cucumber (Cucumis sativus L.). Four types of PGR [indole-3-acetic acid (IAA), 2,3,5-triiodobenzoic acid (TIBA), benzyl adenine (BA), and gibberellic acid (GA3)], which have been shown to enhance fruit growth in non-parthenocarpic cucumbers, were applied using lanolin paste to the peduncles at each node (6-25) of cucumber plants at anthesis. TIBA and BA applications significantly decreased the rate of fruit abortion, thereby increasing yield. IAA and GA3 treatments increased the rate of fruit abortion at the middle and upper nodes, thereby reducing fruit yield. In Exp. 2, to clarify whether PGRs affected the concentrations of endogenous plant hormones, and whether IAA of high concentration increased fruit abortion under low-fruit-load conditions, we applied these PGRs (two concentrations of IAA, BA, and TIBA) to cucumber plants bearing only one fruit at node 11 or 12. No fruit abortion occurred following any PGR or control treatment, although both IAA and BA treatments inhibited fruit growth. BA application increased the production of cytokinins (Z, ZR, iP, and iPR) to a level similar to that after TIBA application one day after anthesis. However, compared with the response to TIBA treatment, after BA treatment, the peak in endogenous cytokinin production occurred at an earlier stage of fruit development. Additionally, both IAA and TIBA treatments increased endogenous IAA and cytokinin concentrations in fruit. These results suggest that exogenous PGRs affect the overall concentration of PGRs, as well as that of other endogenous plant hormones. However, PGRs may not be associated with fruit abortion when the fruit load is low. In conclusion, fruit load may have a greater influence on fruit abortion than that of PGRs.

これまでの研究で，単為結果性キュウリは連続着果させると（着果負担が多いと）後から開花した上位節の花（子房）は成長せずに停滞相に入り，着果負担が解除されると成長を再開し，解除されないとそのまま落果することが報告されている．複数の果実が着生している場合，果実の成長や停滞には果実の（あるいは果実間同士での）内生ホルモンが関与しているという説がある．よって，内生ホルモン濃度を制御することでキュウリの流れ果による収量低下を軽減できる可能性がある．そこで実験 1 では，外生植物成長調節剤（PGRs）が連続着果させた全雌花性キュウリの収量と個々の果実成長に及ぼす影響を調査した．過去に非単為結果性キュウリの果実成長を促進した報告のある PGRs（IAA, TIBA, BA, and GA₃）をラノリンペーストと共に 6–25 節の開花時に各果柄に塗布した．TIBA と BA 処理では無処理より有意に収量が高く，IAA と GA₃ 処理では中位節と上位節の流れ果（落果）が増加し，収量が低下した．また，PGRs によって多数の果実の成長や停滞のパターンや成長開始の間隔が変化することが明らかとなった．実験 2 では，外生 PGRs が実際に内生のホルモン濃度に変化を与えているのか確認するため，また，実験 1 で落果が多かった IAA をさらに高濃度に与えた場合，着果負担が小さい植物体でも落果が生じるのかを確認するため，1 果のみ着果させた植物体に PGRs を与えた．その結果，IAA と BA 処理の果実成長が抑制されたが，過剰に IAA を与えた区も含め，全ての処理区で流れ果は発生しなかった．さらに IAA と TIBA 処理区では果実内の IAA とサイトカイニン類（Z，ZR，iP，iPR）が増加した．これらの結果から，着果負担の小さい状態では PGRs によって流れ果は発生せず，果実内の内生ホルモン濃度だけでは必ずしも流れ果の発生にはつながらないことが示唆された．

明期終了時の短時間の光照射 (EOD光照射) の処理では, PSSがEOD-B区で0.56, EOD-R区で0.89およびEOD-FR区で0.13となった. PSSが最も低いEOD-FR区で茎伸長が促進され, 徒長した. 一方，第1花房着生葉位は試験区間で差がみられなかった. よって, EOD-FR処理によりトマトの避陰反応が誘導されることが示されたが, 花成は促進されなかった. 他方, 明期 (16 h) における遠赤色光量を調節した実験では, 第1花房着生葉位は試験区間で差がみられず, 低R/FR比の遠赤色光が含まれる全処理区で高R/FR比のFR0区と比べて茎伸長が促進され, 徒長した. よって, 明期 のPSSが0.72以下のFR50区、FR100区およびFR150区で避陰反応は誘導するため, 一次育苗で遠赤色光を付加する必要はないことが示唆された. 以上より, EOD-FR処理や低R/FRの条件では, 花成を促進することはなく, 茎伸長を促進するため，閉鎖型苗生産システムではこのような光環境制御は望ましくないと考えられた.

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&mdash;glycyrrhizic acid (GL), liquiritin (LQ), liquiritigenin (LG), and isoliquiritigenin (ISLG)&mdash;in the root of Chinese licorice during post-harvest treatment. The effects of post-harvest storage temperatures (&minus;80, &minus;30, &minus;13, 4, and 25&deg;C) and drying temperatures (30, 40, 50, and 60&deg;C) on concentrations of the four medicinal compounds were investigated. GL and LQ concentrations in roots stored at &minus;30 and &minus;13&deg;C for 1&ndash;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 4&deg;C for 2 weeks were nearly 60-fold higher and ISLG concentrations at 25&deg;C for 1 week were 10-fold higher than LG and ISLG concentrations in the controls. In addition, low temperature (30 and 40&deg;C) 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).

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 -2·s-1 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 -2·s-1 PPF, the total dry weight was not different among the B/R ratios. Under 200 and 300 μmol·m -2·s-1 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.

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 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 -1. 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.

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-2·s-1 with 4 peak wavelengths (465, 530, 595, and 660 nm of 40 and 80 μmol·m -2·s-1, respectively) were set as the controls. Then, the PPF conditions of 120 and 240 μmol·m -2·s-1 were determined by turning off 1 of the 4 peak LEDs. By using the difference between P at 120 and 160 μmol· m-2·s-1 and 240 and 320 μmol·m -2·s-1, 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-2·s-1 than at 160 μmol·m-2·s-1 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.

We assessed the effects of light intensity (photosynthetic photon flux [PPF in &mu;mol&middot;m^-2&middot;s^-1]) 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.

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 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.