Proline is one of the substances which can be used as a parameter of the reaction of a plant to an environmental stress. In this study the changes of proline contents in some ecophysiologically different plants, such as Helianthus annuus and Atriplex hortensis (plants in cool climate regions) and Cicer arietinum, Amaranthus retroflexus and Panicum milliaceum (plants in warm climate regions), were observed when the roots were subjected to high and low temperature stress. When these plants were grown for 2 weeks at 10, 18 and 28°C root temperature, at higher root temperature proline contents of both the roots and the shoots tended to increase in cool climate plants and vice versa, to decrease in the case of warm climate species. On the other hand, when the plant roots were subjected to temperature stress shifting from high to low or low to high and after the shifting they were kept at these temperatures for a short period such as 90 min, the contents of proline increased in both the shoots and the roots irrespective of the temperature shift and the ecophysiological difference of plants. In general, therefore, it seems that the plants tend to accumulate proline when they are subjected to temperature stress at short time. However, the increased proline content in the case of low temperature stress was higher in the warm climate plants than in the cool climate plants.

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This paper reports weight growth of Chrysanthemum coronarium in hydroponic culture under various conditions, measured by continuous and nondestructive weighing systems using load plate as already had been reported.
After 12 day's growth of seeds in constant environment, average weight of 25 seedlings was about 1g. These seedlings were transplanted at intervals of 4 cm in lattice way on the load plate, and cultivated for 18 days in growth chamber under various combinations of temperature, light and nutrient conditions. Light conditions were realized by two 400 W metal halide lamps and four 300 W herogen lamps in use of taking color photograph. Illuminance were controlled by the number of lamps or regulating supply voltage to herogen lamps. Nutrient conditions of hydroponic water were supplied by changing weights of fine grained fertilizer (Hyponex) dissolved in every 10 liters were used in tests. Half of them were in the culture tank and the other in the reservoir tank. They were circulated periodically at every two hours to make their temperature uniform and to supply the air dissolved in them. 10 liters of them were exchanged and supplied by new ones every other day. Temperature of hydroponic water was not controlled, but it was about two or three degrees lower than setting temperatures of growth chamber.
1. After setting various prescribed conditions, tests were carried out and the results as shown in Table 1 were obtained. Maximum fresh yield grew out in the conditions, 25°C, 16 klux, 15 g/10 liters and the mean weights of individual plants was 13.6 g. This value was calculated as 8, 510 kg in terms of yield per 10 are, and it was equivalent to about 3.5 times of average yield harvested in usual farming under structure.
2. Applying weight growth data measured at interval of six hours to exponential growth Eq. (1), it can be considered to be appropriate as regression curve within 50 g that was the total weight of 25 test plants, because the mean value of standard deviation from the regression curve was 2.29 g and this was equivalent to about 4.5% of 50 g.
3. Applying the same data to Robertson's growth Eq. (3), it can not be considered to appropriate as regression curve because the deviation were over from the measured data in logarithmic growth period and existence of upper growth limit was not confirmed in any tests.
4. Growth ratio of plants became small by changing illuminance weaker on the half way of cultivation test. Its degrees of reduction was smaller than that of cultivation test under lighting weaker constantly through all the process
5. Yield, obtained by cultivating under lighting for a given period of hours in every day, can be nearly considered as the value that multiplied the yield gained under lighting continuously for 24 hr by the square of ratio of total hours in lighting intermittently to in lighting continuously.

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To establish a model system to study the influence of air pollutant SO₂ on plant cells, experimental conditions such as medium concentration, pH, sulfite (SO₃^2-+HSO₃^-) concentration were examined using fern Adiantum gametophytes as a plant cell model. Sulfite concentration in culture medium (K-phosphate buffer 1 mM, pH 6.0) changed easily during experimental period by dissolving SO₂ and/or oxidation of sulfite dissolved. SO₂ incorporation into liquid medium is highly related to the flow velocity of SO₂ gas, suggesting that aggitation at the medium surface might be very influential for SO₂ incorporation. Sulfite destruction by oxidation began as soon as Na₂SO₃ was dissolved in medium and proceeded rapidly, but was prevented when fern spores were suspended in the medium at high density (e.g. 1 mg/ml) . Fumigation with 0.1 ppm SO₂ for 5 days greatly reduced the germination rate and the development of gametophytes. The importance of careful arrangement of experimental conditions for studying the influence of air pollutant SO2 on plant cells was discussed.

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Lettuce (Lacluca sativa L. cv. ‘Grand Rapids’) was cultured in a nutrient solution under 342 μE⋅m^-2⋅ s^-1 of photon flux density with metalhalide plus mercury vapor lamp (Ca. 3: 2 installed wattage) .
Optimum concentration of the nutrient solution for the growth of leaf lettuce was 1.5-2.0 times of standard electric conductivity of which is 2.4 mS⋅ cm^-1. Optimum pH and temperature of the nutrient solution were about six and about 25°C, respectively. Morphological disorder was not found in these conditions.

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A system for on-line and real time measurement of water flow rate in a plant stem was developed on the basis of stem heat balance simplified by the heat flux control. Heat (Q) supplied from a main heater attached to the stem surface is diffused through heat flux (q_f) by water flow in the stem, heat flux (q_s) from the surface of the main heater to the surroundings, and upward and downward heat fluxes (q_u andq_d) by conduction in the stem, that is, Q=q_f+q_s+q_u+q_d. In this system, q_swas kept constant by controlling Q, andq_uandq_dwere also kept constant by controlling two subheaters attached to upside and downside of the main heater. Thus, change in theQdirectly related to fluctuation ofq_f. So, water flow rate in the stem was able to be calculated from the theoretical equation (Eq. (5) ) by usingQand temperature difference (T_u-T_d) in the stem between upside and down-side of the main heater. We proposed to call this system “Heat Flux Control method (HFC method) .” From dynamic and static characteristics of the system in a glass tube used as the stem model and in an intact plant, it was estimated that HFC method can be used as a reliable tool for quantitative analysis of water flow in the stem and applied to researches on water process in the plant.

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Seeds of eggplant, cv. ‘Hayabusa’ and sweet pepper, cv. ‘Tosashishitohgrashi’ were sown in a bed filled with sand. After cotyledon expansion, seedlings were pricked off into 12 cm polyethylene pots with three seminal root treatments, 1) keeping seminal root vertically, 2) pruning seminal root, and 3) keeping seminal root in curl. All seedlings were raised for 50 days and then transplanted into a vinyl-house.
The growth of seedlings was promoted by keeping seminal root vertically at potting time compared with that of the seedlings with pruning seminal root and that of the seedlings that kept seminal root in curl. Seedlings that kept seminal root vertically showed lower ratio of top weight to root weight with a higher root and lower shoot percentage of dry matter distribution than other seedlings.
The higher yield was obtained on the plants from the seedlings that kept seminal root vertically, which grew faster, developed a deeper and wider root system consisting in a lot of thick roots over 1 mm in diameter after transplanting both in eggplant and sweet pepper raised in two kinds of bed soil. Pruning or keeping seminal root in curl retarded the subsequent growth and reduced the yield.
The yield was closely correlated to the number of thick root over 1 mm in diameter. As the number of thick roots increased, the yield was higher.
Plants that had a lower ratio of top weight to root weight at transplanting time developed better and showed higher yield. There was a correlation between this ratio and yield, although significance was just found in eggplant but not in sweet pepper.

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Top fresh weight of leaf bunching lettuces (Lactuca sativa L. cv. ‘Grand rapids’) in hydroponics were continuously measured under the conditions changing in relative humidity, air temperature and light intensity.
Reversible fluctuations of top fresh weight were observed. The fluctuations started immediately after the changes in environment, and continued within 30 minutes after the changes. Light and air temperature were more effective on the fluctuation than relative humidity.
The fluctuations were distinguished from long-term changes in fresh weight by its reversibility. The transpiration rate showed opposite pattern of the fluctuation caused by environmental change.
These results suggest that short-term fluctuations reflect the balance of input and output of water which may be regulated by transpiration.

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