A feeding actograph consisting of an activity detector, an amplifier, a pen-recorder and a timer circuit was designed to determine the daily change in feeding activity in the silkworm Bomcbyx mori L. Masticatory motions were detected by the changes in electrical resistance between an electrode implanted in the haemocoel of the thorax and the second electrode attached to the artificial diet. The main circuit of the amplifier was made up with a simple magnifier and a voltage comparator. A voltage comparator effectively functioned to eliminate noises. To get the signals driving the timer circuit, an integrating circuit was provided. The timer circuit includes an electronic relay, a clock pulse (1 Hz) generator, a pulse counter and a digital printer. By use of this instrument, the feeding rhythms in the 5th instar larvae of the silkworm were analused in several lighting resumes such as 8L-16D, 12L-12D, 16L-8D and 20L-4D. In the long-day condition of 20L-4D, the activity value of feeding—total duration of active feeding (min) measured in 2-hour intervals—fluctuated in monophasic pattern with a peak at the middle part of photophase, while in the short-day conditions below 16L-8D, the value fluctuated in bimodal pattern with the 1st peak at the middle of photophase and the 2nd peak at 7th-8th hour period of darkphase. These facts seems to suggest that the timing of silkworm feeding was adjusted by both of the diurnal type rhythm mechanism and the nocternal type rhythm mechanism.

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Tomato (cv., Fukuzyu No.2), eggplant (cv., Hayabusa) and sweet pepper (cv., Shinsakigakemidori) were grown in a nutrient solution under glasshouse conditions and in soil bed in vinyl-house, respectively, in order to clarify the influence of additional supply of iron, manganese and copper on their growth, yield and absorption of water and mineral elements.
1. Additional supply of iron resulted in a remarkable decrease in growth and yield of tomato plants and increased dry and fresh weight and yield in eggplant, whereas manganese supply enhanced the growth and yield in tomato and greatly diminished dry and fresh weight and yield in eggplant plants. In the case of sweet pepper plants, copper supply promoted significantly the growth and yield.
2. There was a close positive correlation between the number of thick roots over 1 mm in diameter and yield in all plants tested.
3. Plants grown under additional supply of iron, manganese, and copper, respectively, showed the increase of iron, manganese, and copper concentration in the plant tissues with significantly higher iron content in the root. Antagonistic action between iron and manganese was observed in all plant parts.

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Effects of temperature and fertilizer application level during the period of seedling raising on the growth of seedlings and subsequent yield in eggplant was evaluated.
High temperature and heavy fertilizer application promoted the growth of seedlings with an increase in dry weight. The seedlings held at 30°C (day tempera-ture) -25°C (night temperature) and 30°C-20°C under heavy fertilizer application condition had the weightiest dry matter, showing larger value of stem weight to root weight with a higher stem and lower root percentage of dry matter distribution than those grown at lower night temperature under light fertilizer application condition. S/R value of seedlings was larger at 30°C day temperature than those at 25°C or 20°C. Seedlings with the smallestS/Rvalue was produced at 25°C-20°C under light fertilizer application condition.
Plants from the seedlings raised at 25°C-20°C, 25°C-15°C and 30°C-20°C under light fertilizer application condition produced the highest yield. Seedlings with lowerS/Rvalue at transplanting time developed well, formed more thick roots over 1 mm in diameter, produced higher yield after transplanting. There was a correlation betweenS/Rvalue and the yield.
As the number of thick roots increased, the yield was higher, there also found a close correlation between the number of thick roots and yield.

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Tomato (Fukuzyu No.2), eggplant (Hayabusa) and sweet pepper (Shinsakigakemidori) were grown in water culture under glasshouse condition in order to clarify the influence of concentrations of nutrient solution on their plant growth, exudation rate and chemical composition of xylem exudate.
1. Plants grown in standard solution had the greatest dry weight in each crop, followed by a decline with those supplied with lower or higher concentration of nutrient solution, with the degree of dry weight reduction in the following descending order: sweet pepper, eggplant and then tomato.
2. Exudation rate in each crop was similar to dry weight tendency, with a negative correlation between the concentration of nutrient solution and exudation rate.
3. An increase in the concentration of nutrient solution suppressed Ca absorption but promoted other minerals. It was shown that the levels of NO₃-N, Ca and Mn in eggplant and P, K, Mg, Fe, Cu and Zn in sweet pepper were higher in comparison with the other crops, respectively. Tomato had lower levels of mineral elements in the xylem exudate than eggplant and sweet pepper, but it had the greatest amount of mineral absorption per plant per hour because of its high exudation rate.

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The influence of day-length on the eggplant, cv.‘Kokuyou’seedlings, which were grown under 6-, 8-, 10-, 12-, 16-, 18-hr day-length and natural day-length (13-14 hr), was investigated. The results obtained are summarized as follows.
1. The growth of seedlings became vigorous as the day-length became longer until 16 hr on the dry weight basis, thereafter was inhibited with a decrease on chlorophyll content. Chlorosis appeared only at 18 hr day-length plot. Seedlings grown under natural day-length showed the smallest value of stem weight to root weight (S/R) compared with those grown under either shorter or longer day-length condition. It was found that leaf area of seedlings grown under 6-8 hr short day condition expanded with pale green and little dry weight.
2. Plants from seedlings grown under natural long day condition showed the highest yield with deeper root distribution pattern affected by a lot of thick roots over 1 mm in diameter. On the contrary shading or supplemental lighting during raising seedlings supressed the growth and yield with a shallow root system distribution.
3. It was clearly found that there was a negative correlation betweenS/Rvalue and yield, and a positive correlation between the number of thick roots and yield.
4. From the above-mentioned results, it may be concluded that longer natural day-length during raising seedlings is favorable for subsequent growth and yield.

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The experiment was carried out to study the effects of soil compaction in pot by packing soil into pot at the beginning of raising seedlings on the growth of seedlings and their subsequent yield in eggplant and sweet pepper.
(1) SmallerS/Rvalue with high dry weight were found in the seedlings grown in pot incompactly filled with soil only or 1 soil: 1 bark compost (v/v) than those grown in compact media in both eggplant and sweet pepper. However incompact packing of bark compost into pot inhibited growth of seedlings in egg-plant, but not in sweet pepper. Incompact media promoted the partitioning of dry matter to root and reduced to stem, resulting in a smallerS/Rvalue.
(2) Plants from seedlings grown in incompact packing pot developed better, showing a deeper and wider root system consisting in a lot of thick roots over 1 mm in diameter after transplanting, produced more yield than those grown in compact packing pot with all of 3 media for sweet pepper, with soil only or 1 soil: 1 bark compost media for eggplant. Bark compost media inhibited growth of seedlings, resulted in less yield than other two media.
(3) Seedlings with larger leaf area and smallerS/Rvalue at transplanting time showed the vigorous growth with a higher yield than those with a largerS/Rvalue or a smallerS/Rvalue with little leaf area. LargerS/Rvalue was not favorable for increasing the yield in both eggplant and sweet pepper.
(4) In eggplant, the yield was closely correlated to the number of thick roots over 1 mm in diameter. The more the number of thick roots, the higher the yield. Similar result also was obtained in sweet pepper.
(5) It may be concluded that keeping soil loosely is very important during the period of raising seedlings in eggplant and sweet pepper.

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