Changes in environmental factors were investigated in NFT system where 12 strawberry cultivars were grown. While the solution temperature was regulated at three levels, transition of air temperatures, solution temperatures at the channel and plant temperatures were measured. At relatively high air temperature in autumn, the concentration of dissolved oxygen at the lower part of channel decreased a little than in the upper part. However, at low air temperature in winter, the concentrations of dissolved oxygen at the lower and upper parts were almost the same.
When the daytime air temperature in the plastic house was higher than the solution temperature in the tank, the lower the part of channel, the higher the solution temperature was tend to be. On the contrary, when the daytime air temperature in the plastic house was lower than the solution temperature in the tank, the lower the part of channel, the lower the solution temperature was tend to be. These tendency became obvious as the difference between air temperature in the plastic house and solution temperature at the tank increased.

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CO₂ enrichment under a high photosynthetic photon flux density of 150 μmol m^-2s^-1, which is 2-3 times that in conventional plant tissue culture, was effective for promoting growth of miniature rose (Rosa hybrida Hort., cv Mary Antwernett) plantlet in vitro. Growth was greater under photoautotrophic conditions than under photomixotrophic conditions. Photoautotrophic growth was greater when CO₂ concentration in the culture room was higher.

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We analize numerically the profit and optimum environmental conditions for a completely controlled plant factory using the growth data of lettuce and cost data of Miura Farm. We introduced the profit function and instantaneous cost-performance as evaluation functions. This is the first paper to evaluate a plant factory completely quantitatively.

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A growth model for a leaf vegetable suitable for a plant factory is developed which includes the effect of source and sink-dependent photosynthesis and translocation. Depending on the relative size of these coefficients, it is shown that plant growth is accelerated or decelerated compared with usual exponential growth. This fact suggests the importance of activation of root and rapid translocation.

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The image processing of plant growth is an effective tool for intact and non-destructive measurement, so as to be able to digitize continuously the images of plant or leaves with the computer system. However, it requires a lot of know-how responded to the features of the object plants. We have, therefore, developed several image processing methods for obtaining the accurate information about the vegetables grown in a plant factory. The image processing procedure of vegetables was composed of basical image processing functions such as sharpening, smoothing, expansion, contraction, deleting of noise and filling hole. In order to recognize individual plant growth continuously, we have developed the labelling algorithm by calculating the distance between center of gravity and set point. Furthermore, the transformation of growth was intelligibly observed by the superposition of outlines and the skeleton by thinning of binary images in the growth stage.
In conclusion, these techniques made it possible to realize automatic measurement and development of the plant growth monitoring system in a plant factory.

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In order to analyse the effect of “Amenity Plants”on environment inside room, the authors measured transpiration rate, stomatal resistance and shading ratio of eight kinds of ornamental foliage plants.
In the first place, transpiration rate and stomatal resistance were measured in a controlled glasshouse in Ehime University. Diurnal changes in transpiration rate under air temperature of 27°C are shown in Fig.1, indicating that transpiration rate of Scheffleraera arboricola“Hong Kong” is more than those of the other plants. Figure 2 shows relationship between solar radiation and stomatal resistance. Stomatal resistance of the plants except Dracaena fragrans “Massangeana” increases according as solar radiation decreases.
Schematic diagram of measurement blocks in which shading ratio was measured is shown in Fig.3. Figure 4 shows shading ratio in each block and average shading ratio of the whole plant of Schefflera arboricolacola “Hong Kong” in relation to angle of light incident. Figure 5 shows relationship between angle of light incident and average shading ratio of the whole plant of eight kinds of ornamental foliage plants. Shading ratio except Schefflera arboricola “Hong Kong”and Epipremnum aureum approaches to 1.0 according to increase of angle of light incident.
The data obtained in this experiment would be important when we make simulative estimation of the environment inside room from green amenity aspect.

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Fruit cracking in cherry tomato was simulated using finite element methods to identify the primary cause of initiation of skin rupture. The main interest of this analysis was to revile the relationships between hoop stress in the skin and moisture conduction of the skin under influence of ambient water potential.
The water potential was selected as a key parameter to govern moisture movement through the skin. A finite element program was developed to incorporate the variation of water potential gradient existing between interior and exterior of the skin into the stress calculations. The most unique aspect of this finite element calculation was to include the convection term in the element conduction matrix. This treatment can be allowed in which the water potential is considered as an energy parameter. The transpiration coefficient, of which inverse is transpiration resistance, was defined as a physical property of skin to calculate water potential distribution in a fruit.
The simulation results indicate that the suppression of transpiration from skin due to increase in ambient water potential creates hoop stress large enough to rupture the skin. The tomato fruits that have smaller transpiration coefficient tend to experience larger hoop stress. A field experiment also showed that grease coated tomato fruits of which transpiration resistance was artificially modified to be infinity became much more susceptible to cracking than untreated fruits.

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When ozone was used to the sterilization of the solution of soilless culture, the increase or decrease of the nutrient ion elements in the solution and the variation of chemical characteristics were examined in a laboratory.
In the case of cucumber Fusarium baccili, the treatment conditions which indicated strong lethal effects were the dissolved ozone concentration of over 0.25 mg/l and treated period of 10 min for microconidia, while the concentration of over 0.4 mg/l and the period of 5 min for chlamydospore, respectively.
Therefore, the ion elements in each solution after exposed to two ozone concentrations of 0.25 and 0.5 mg/l and chemical characteristics as an electric conductivity (EC) and pH were measured, and each percentage of variations to control of 0 mg/l were calculated.
As the results, in the case of the ozone concentration of 0.5 mg/l, the maximum percentage in every ion variation was below 18%, whereas each value of EC and pH together unchanged by the ozone treatment.

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Although measurements on plant geometry are important for the analysis of plant growth and have many possibility of applications, few attempts are made on the precise measurement of three dimensional (3-D) plant shapes. In this study, 3-D plant shapes are measured by using a magnetic 3-D digitizer which can detect 3-D locations of the sensor. Measured point data are expressed as a set of polygons and are visualized by using computer graphics. The example of measurements and visualization of Phalaenopsis leaves is shown.

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