A device for mechanical stimulation was developed to produce tomato seedlings at a high planting density. 1) The device could be moved automatically and enabled to change freely the operation time, traveling velocity and height. By this device, mechanical stimulation was applied near the growing points of the seedlings at the 2nd leaf stage for 20 days, the traveling velocity was 10 m/min, and the frequency one stroke per 30 min. 2) The mechanical stimulation of the seedlings exerted a favorable effects on the uniformity of stem length and the improvement of the percentage of dry matter as well as the prevention of spindly growth, without affecting adversely the dry matter production and the formation of flower buds. 3) It was possible to produce tomato seedlings at a high planting density by mechanical stimulation. Maximal planting density was about 1, 000 plants per m² for seedling production at the 4th-5th leaf stages, and about 400 plants per m² at the 6th-7th leaf stages. 4) Although seedlings in tissue-culture display considerable individual variations in growth at the early stage, mechanical stimulation exerted favorable effects on the uniformity of stem length and fresh weight of the seedlings.

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Effect of types of culture vessels with supporting materials on the growth of carnation plantlets in vitro has been investigated. The experiment was carried out using Sorbarod System (plastic vessel) with Sorbarod (fibrous cellulose plug) ; called SS hereafter, Star Pac (gas permeable plastic bag) with agar; called SP, test tubes with agar capped with gas permeable plastic film; called TF and test tubes with agar capped with aluminum foil; called TA. The numbers of air changes per hour of SS, SP, TF, and TA vessels were, respectively, 9.6, 0.23, 5.3, and 0.32. The experiment was carried out at a photosynthetic photon flux of 60 μmol⋅m^-2 ⋅sec^-1 (ca. 4.5 klx) for 16 hr per day and a room air temperature of 25°C.
On day 40, the greatest average fresh weight of plantlets, the largest percent dry matter, the smallest top/root fresh weight ratio and the shortest shoot were observed in Treatment SS. The percent dry matter, top/root fresh weight ratio and shoot length in Treatment TF were similar to those in Treatment SS. Some multiple shoots were observed in Treatment SP. Some plantlets were vitrified in Treatments SP and TA.
The results indicate that the combination of the culture vessels with a high number of air changes per hour and the fibrous supporting materials promotes the growth of carnation plantlets in vitro.

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Deviation in the horizontal distribution of air and soil temperature beneath film mulch was studied in relation to meteorological conditions in a greenhouse and upland field. The following results were obtained. (1) From measurements of solar radiation of 10 points in the greenhouse with east-west direction, standard deviation of 10 sky solar radiations was 122% that of direct solar radiation. Changes in air temperature at 150 cm height as measured at the same position that of the solar radiation increased considerably with approach to gable side equipped with a ventilation fan. For relative humidity at 150 cm, no characteristic tendency was observed. (2) For the greenhouse and upland field, large differences were found between standard deviation in 10 soil temperatures at 10 cm depth in daytime and that of nighttime. Diurnal range of the deviation in the greenhouse was about twice that of upland field. (3) Standard deviation in 10 air temperatures and 10 soil temperatures in a horizontal direction in broad bean field and soybean field was investigated by multiple regression analysis using predictor variables of 5 principal meteorological factors and LAT. The deviation of air and soil temperatures was significantly influenced by solar radiation in the broad bean field, and by solar radiation and LAI in the soybean field. (4) Amount of heat load in the greenhouse and daily variation in heat transfer in the soybean canopy were calculated in relation to deviation in air temperatures in a horizontal direction.

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A local area network (LAN) for a plant factory was designed. In this LAN, three types of computers, an AT computer (AI), a workstation (WS) and a terminal computer (TC) were connected by Ethernet.
The file transfer speeds between the computers by using FTP command were examined as the following 4 conditions; (1) TC was used as a client and WS was used as a server, (2) WS was used as a client and AT was used as a server, (3) AT was used as a client and WS was used as a server and (4) TC was used as a client and AT was used as a server. The file transfer speed was the fastest in the condition (1), and the slowest in the condition (3) .
Furthermore, other two data acquisition commands in addition to FTP command were used in order to characterize the condition (1) . The two commands were COPY command in Network File System (NFS) and ONE LINE COPY command in NFS. A file transfer speed from TC to WS was the highest when FTP command was sent. A file transfer speed from WS to TC was the highest when COPY command in NFS was sent.
The effect of the file size on the file transfer speed in the condition (1) was tested by using the following three file sizes; 768, 000 bytes, 384, 000 bytes and 96, 000 bytes. File transfer speed was the same when COPY command and ONE LINE COPY command in NFS were used, i.e. independent on the size of files. However, when FTP command was used, larger size files were transferred faster than smaller size files. Thus, it was found that large file sizes such as image data could be transferred most effectively between computers by using FTP command.

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Application of still picture communication systems for agricultural production will bring such many advantages as labor saving for maintenance, progress of production technique and profitable shipping control of products. And by connecting these systems with computer technique for information processing, they will have great possibilities to create total expert systems for operational and technical consulting and automatic sensing and control of plant states, based on various types of information such like picture and letters sending from remote station on the process of agricultural production. These line of research have just started. In this paper, a computer system for analyzing vegetable pictures received at regular interval through telephone line by making use of the still picture communication systems was built up, and a possibility of growth analysis was examined by simply processing these pictures. These possibility seemed to be confirmed, even though these pictures were received on the basis of short term cultivation tests.

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