Concentrations of nutrient solution can be expressed in terms of water potential instead of electric conductivity (EC), which is used conventionally in management of nutrient solution concentration in plant growth factories. Water potential is a convenient concept to use when expressing directions of water flow in plants, and therefore, may be useful in the regulation of growth of plants cultivated in plant growth factories. In the present study, Phaseolus vulgaris seedlings were used to study relations between growth and water status when concentrations of nutrient solution were changed. Growth inhibition under high concentrations of the nutrient solution was not related to turgor in the elongating region, but was co-related with the magnitude of the growth-induced water potential, which was estimated from the difference between water potentials of the mature region and the elongating region. Because the growth-induced water potential determined cell expansion, it can be safely stated that growth of plants in plant growth factories can be regulated if the growth-induced water potential can be measured, although simple measurement methods for growth-induced water potential have not yet been developed.

View full abstract

In order to develop the environmental control system based on plant responses, the bioelectric potential transition patterns on Spinach lamina in response to light-on were measured as an useful plant physiological information.
The obtained results are summarized as follows;
1. These bioelectric potential transition patterns were changed by air temperature, relative humidity, CO₂ concentration, light intensity, plant growth and dying process.
2. One specific peak of this pattern was related with the rate of photosynthesis.
3. These transient pattern changes of bioelectric potential can be simulated by the exponential function.
4. Our study also suggests the possibility of expressing some relations between culture environmental conditions and growth conditions by means of function parameters.

View full abstract

A computer vision system (256×256 pixels, 64 gray levels) was used for the nondestructive evaluation of the degree of cracks in rice. White spot light applied to a rice kernel parallel to its major diameter in a dark room provided the best viewing conditions.
The principle of evaluation was based on four indices extracted from both gray level profile and gray level histogram. Each index was numerized by the membership function. The fuzzy integral was used to put four values of indices together and the extent of cracks was numerically presented. With the algorithms developed, damaged kernels ware detected with an error rate of 2%.

View full abstract

The purpose of studies on the process from seeds to germination of Sandersonia Aurantiaca lies in creation of the optimum condition for a period from germination from seeds which depend much on the atmospheric temperature, first of all.
Investigating the germinating condition of seeds sown on the nursery one by one, we made investigation on the relations between period after germination and atmospheric temperature.
Secondly, we investigated the relations between temperature and break period of dormancy by storage of tubers at a low temperature after formation of tuber as well as took up a problem of waking up treatment from dormancy after that.
Thirdly, we checked the period required for one generation cycle and investigated in what way we should quicken cultivation from tuber. As mentioned, if it is possible to germinate from seeds and form tubers simply in Japan, we shall not be required to rely on importation of tubers of Sandersonia Aurantiaca in the future.

View full abstract

Recently, we often hear the word “amenity”. The amenity effects of plants on human being is called “green amenity”. The authors recognize the importance of “green amenity” and are making a series of studies on “green amenity”.
The green amenity effects can be divided into perceptible effect, environmental control effect and image effect (Fig. 1).
In this paper, the authors focused on the environmental control effect by plants, and made simulation of inside environment of two types of office rooms; the one has plants in it and the other has no plants.
The authors assumed simulation model shown in Fig. 2 and Table 1, and made simulation according to the flow chart shown in Fig. 3. The plant in the room was tomato plant, and its relationship between light intensity and stomatal resistance is shown in Fig. 4.
The result of simulation on the standard sunny day in December is shown in Fig. 5, indicating that the inside air temperature with plants is lower than that without plants in the daytime and that the maximum temperature difference is 2.6°C.Figure 6 shows that the maximum temperature difference on the standard sunny day in July is 2.7°C.

View full abstract