The objective of this study was to detect the plant stoma response under the lighting conditions of continuous and 1 to 15 minutes of lighting. In this study, a real-time measurement system was developed to observe a living plant stoma continuously for a long period in a growth chamber, using a microscope and a color TV camera. A video recording system was adopted to obtain details of stoma movement, and images were captured every 30 seconds. From the experimental results, it was observed that the stoma opened slowly 5 minutes after the lights were turned on, and then opened rapidly until it reached the maximum pore size. In guard cells, light stimulus activates a proton pump, the resulting hyperpolarization of the plasma membrane opens voltage-sensitive K⁺ channels, and then the water entering the guard cells opens the stoma after the K⁺ ions have entered. This process may cause 5 minutes of delay, and delay was also observed after the light was turned off. Ten minutes of lighting opened the stoma to the maximum size, as well as 5 minutes of lighting with a 30-minute interval. For better utilization of lighting, these on/off controls were suggested to give a 14% production benefit with 8.3% more energy input.

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To identify the effects of seasonal temperature on geranium flowering throughout year-round cultivation in a greenhouse, the flowering characteristics of 4 wild species, 2 varieties and 13 hybrid derivatives were investigated at 4 times : May, August, and November in 2002, and February in 2003. Based on these results, the possible usage of high-temperature stress tolerance in hybrids was discussed.
The daily mean temperatures were 20∼23°C in May, 28∼31°C in August, 12∼13°C in November, and 9∼11°C in February in the greenhouse. It was 26∼32°C from the first 10 days of July to the middle 10 days of September, the most severe high-temperature term for geraniums.
The flowering characteristics varied among seasons, and the general trend was that the appearance was the worst in August. Seasonal change in peduncle number was different among the strains. In August, peduncle length and floret number per peduncle decreased obviously. From the variation pattern, it was found that the high temperature in summer greatly affected the flowering characteristics for a long period. Correlations between the parents and their hybrids were positive in all flowering characteristics. For breeding high-temperature stress-tolerant hybrids, the selection of high-temperature stress-tolerant strains for parents may be efficient. Strains 9, 10, 11, and 13, which are descendants of P. frutetorum, P. salmoneum, and P. inquinans, respectively, showed hybrid vigor throughout the year-round cultivation. Strain 10, especially, showed higher hybrid vigor for all traits in August, making it useful for year-round cultivation in the greenhouse.

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This research was conducted to develop an algorithm to recognize the number of days after planting of lettuce in a plant factory. Speaking Plant Approach (SPA) has been recognized in a growth control system. Growth information should be utilized actively for environmental control. An instrumentation that can acquire the growth information is necessary to incorporate the SPA into the growth control system. This research is a fundamental analysis for a growth monitoring method. Two varieties of lettuces, the Telme lettuce and the Tango lettuce, were examined. Digital images of the lettuces were photographed by a digital still camera. Several image features, such as the top projected leaf area, the color attributes and the texture features, were calculated using an image processing algorithm. Linear discriminant analysis was adopted for the image features. This research focused on three dates in a growth term. As for the Telme lettuce, the 10th, 20th and 30th days after planting were set as the target dates to note. For the Tango lettuce, the 7th, 14th and 21st days were fixed as objectives. The developed algorithm showed a 2.5% error rate for the Telme lettuce and 20% for the Tango lettuce. Therefore, this recognition method could be utilized for a growth diagnosis of the Telme lettuce. On the other hand, for the Tango lettuce, it is necessary for the algorithm to be further improved.

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In our previous study of measurements of bio-electric potential of Grifola frondosa, a rhythmic fluctuation was often observed in the bio-electric potential reaction, even when light stimuli were applied at regular intervals. If there is any relationship between the duration of light/dark and the rhythmic fluctuation of bio-electric potential, it could be worthwhile to investigate any corresponding relationship to the growth control of mushroom. In this study, the characteristics of rhythmic fluctuations, both for the fruit body and the primordium of Grifola frondosa were investigated, focusing on the reaction of the bio-electric potential when light stimuli were applied to the mushroom on a regular cycle of light/dark conditions for many hours. As a result, rhythmic fluctuation characteristics in the bio-electric potential of the fruit body were confirmed. An approximate cycle was noted between 13 to 64 hours, which tends towards a 1/f² characteristic fluctuation. On the other hand, although the dependence of bio-electric potential changes on the light stimuli was not observed in the primordium, a bio-rhythm was noted, with an approximate periodic characteristic between 14 to 68 hours, tending towards a 1/f² fluctuation as in the fruit body.

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The software for automatic ion control of nutrient solution for hydroponics, named “IonAdjuster”, was invented and inspected practically. The ion unbalance problem in the nutrient solution sometimes occurred due to the uneven distribution of ion error range, in the software. To improve the precision of calculation of nutrient solution, Tolerance method and Least squares method were developed and examined.
Least squares method was suggested as the most suitable way in calculating a supply of fertilizer to the nutrient solution for compensation of ion concentrations.

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Factors affecting the induction of the metabolic activity of tropane alkaloids in shoot cultures of Duboisia myopoloides were investigated. In shoot cultures of Duboisia myopoloides, hyoscyamine was efficiently taken up and converted metabolically to 6β-hydroxyhyoscyamine and scopolamine. These metabolic activities were induced by light irradiation concomitant with the addition of hyoscyamine to culture medium. Hyoscyamine-6β-hydroxylase activity endorsed this phenomena.

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The effects of various culture conditions on the shoot growth of Fragaria ananassa were examined. To multiply the shoots efficiently, modified MS medium (with the concentrations of NH₄NO₃, KNO₃ and CaCl₂·2H₂O halved) supplemented with 1 mg/l 4PU (N-(2-chloro-4-pyridyl)-N'-phenylurea), 30g/l sucrose and 8g/l agar was selected as the optimum medium. Multiplied shoots were transferred to liquid medium and the effect of shake culture conditions on shoot growth was examined. The results revealed that the use of halved strength modified MS medium containing 30g/l sucrose stimulated the growth of shoots in a shake culture. According to the results obtained, the use of a bioreactor containing the selected medium for the production of plantlets, and reestablishment in soil, will be a sufficient method for mass propagation of Fragaria ananassa plants.

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A simple method of genetic transformation of leaf lettuce (Lactuca sativa L.) by infection of the seeds with Agrobacterium tumefaciens was investigated. Sterilized and water-imbibed seeds were vacuum-infiltrated with a suspension of A. tumefaciens that harbored pIG121-Hm. After co-cultivation, the shoot primodium tissue was induced on a medium that contained antibiotics, for elimination of the bacteria and selection of transgenic cells. Plants regenerated on the selection medium showed GUS activity. These results indicated that transgenic leaf lettuce can be developed using the seed infiltration method.

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