Astringency in a Japanese persimmon (Diospyros kaki Thunb.) fruit is mainly caused by soluble tannin. A computer image analysis method was tried for easier, quicker and more accurate measurement of soluble tannin content in persimmon fruit. Perpendicular sections of fruits of Japanese persimmon cvs. Hiratanenashi and Monpei were printed on filter papers dipped in 3% FeCl₃ solution. The mirror images on the filter papers were digitized by a gray scale image scanner. These digital images were thresholded, and the percentages of black pixels in transverse images were counted as an index of soluble tannin content, named tannin index. The tannin index was compared with the soluble tannin content measured by the Folin-Denis method. The tannin index correlated highly with the soluble tannin content in both cultivars, and this indicates the image analysis method is capable of measuring soluble tannin in persimmon fruit.

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Scales of regenerated bulblet of Lilium japonicum Thunb. were embedded on MS-media containing of 24-epibrassinolide (EB: 0, 0.001, 0.01, 0.1 and 1.0 mg L^-1) and NAA (0 and 0.1 mg L^-1), and then cultured under continuous light of 60μmo1 m^-2 s^-1 at 25°C for 10 weeks in vitro. The numbers of adventitious bud and bulblets formed on the scale were counted on 2, 4, 6, 8 and 10 weeks after culture. The formation of the adventitious bud primordia was promoted by 0.1 and 1 mg L^-1 EB and/or the combination of 0.1 mg L^-1 EB and 0.1 mg L^-1 NAA. The formation of the regenerated bulblets was promoted by the combination of 0.01 and 0.1 mg L^-1 EB and 0.1 mg L^-1 NAA, but inhibited by the combination of 0.1 mg L^-1 EB and 0.1 mg L^-1 NAA. Rooting from the regenerated bulblets was promoted by the combination of 0.01 mg L^-1 EB and 0.1 mg L^-1 NAA. Emergence of scale leaf from the regenerated bulblets was enhanced by EB, and the adventitious bud primordia and the regenerated bulblets formed on the media containing 1 mg L^-1 EB showed a deep green color.

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Effects of daylength and temperature on capitulum initiation and development of garland chrysanthemum (Chrysanthemum coronarium L.) were investigated. Four cultivars different in earliness to flower were used. When the cotyledon expanded, the seedlings were transferred to phytotron for 75 days at 15, 20, 25 and 30°C under short day (10 h) or long day (16 h), respectively. Capitulums of “Hakata kairyo chuba” were initiated at 15 and 20°C under long day, 30 days after the treatment. The floral stages at 15 and 20°C were late floret-forming and early floret-forming stages, respectively. Fortyfive days after the treatment, floral stages at 15 and 20°C under long day further developed to early corolla-forming stages. Sixty days after the treatment, capitulums at all temperatures under long day were initiated and those floral stages in plots 15, 20, 25 and 30°C were late corolla-forming stage, late corolla-forming stage, early corolla-forming stage and late involucre-forming stage, respectively. Capitulums of “Otafuku” 60 days after treatment, and of “Kabuhari” and “Oba” 75 days after treatment were initiated at 15°C under long day, but they were not initiated under short day. In the case of “Hakata kairyo chuba” whose capitulums were initiated in any temperature, the lower the growing temperature, the fewer the number of nodes from cotyledon to capitulum. From these results, it was deduced that capitulum initiation of garland chrysanthemum was induced by long day, and the lower the growing temperature, the more it was promoted.

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In order to obtain basic data of evolution of ethylene from lettuce plant (Lactuca sativa L. cv. Okayama), ethylene concentration was measured in a closed chamber in which the plants were cultivated under controlled environment (25°C air temperature, 60-70% relative humidity, 200μmol m^-2 s^-1 photosynthetic photon flux density (PPFD), continuous lighting, 400μL L^-1 CO₂) . Ethylene release rates of intact lettuce plant on a fresh weight basis (E_f) and on a dry weight basis (E_d) ranged from 0.1 to 0.25 nmol g^-1 h^-1, and from 1.2 to 3.1 nmol g^-1 h^-1, respectively. These rates gradually decreased as the plant grew. The ethylene release rates on a leaf area basis (E₁) remained constant (0.6 nmol dm^-2 h^-1), independent of leaf area. Ethylene release rates of intact lettuce plant were affected by cultivation conditions such as ambient CO₂ concentration, light intensity and light/dark period. E_d and E₁ of lettuce plant cultivated at 2000μL L^-1 CO₂ were 1.4 times and 1.7 times, respectively, as much as those of the plant cultivated at 400μL L^-1 CO₂. E_d of lettuce plant was slightly higher in 300μmol m^-2 s^-1 PPFD than in 150μmol m^-2 s^-1 PPFD. E₁s were similar to each other in both PPFD. E_d and E₁ of lettuce plant cultivated at 12 h light/12 h dark period were 1.9 times and 1.7 times, respectively, as much as those of the plant cultivated at continuous lighting.

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Lettuce plant (Lactuca sativa L. cv. Okayama), which is a candidate for vegetables cultivated in Controlled Ecological Life Support Systems (CELSS), was exposed to ethylene. Effects of ethylene on the plant growth were investigated in order to determine an allowable level of ethylene. Although a few reports showed a decrease in rates of photosynthesis and transpiration of some plant species by 1.0μL L^-1 ethylene, no decreases in the rates of lettuce plant were observed at 0.1 to 1.0μL L^-1 of ethylene under any photosynthetic photon flux density (130, 270, and 380μmol m^-2 s^-1) . Then, the plant absorbed ethylene and the absorption rate increased with ethylene concentration. But the plant did not absorb ethylene under dark conditions. This fact might mean that lettuce absorbed ethylene mainly through stomata. The plant cultivated at 0.5μL L^-1 ethylene for 10 days showed epinasty, chlorosis and inhibition of leaf expansion. These phenomena resulted in growth inhibition of lettuce plant. Leaf expansion of the plant cultivated at 0.1μL L^-1 ethylene was also significantly inhibited. The plant growth rate was slightly lower compared with plants grown in ethylene-free air. From these results, it is obvious that a low concentration of ethylene influenced leaf expansion and chlorophyll degradation of lettuce plant, but not the rates of photosynthesis and transpiration. The allowable level of ethylene for lettuce plant seemed to be about 0.1μL L^-1.

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Recently Eustoma grandiflorum (Raf.) Shinn. has become a popular ornamental cut flower primarily because of its range of flower colors and longevity. Production from June to September accounts for 80% of annual output, with a maximum in July (25%) and only 5% between November and April. New techniques that result in stem elongation and flowerings of rosetted plants have now resulted in a rapid expansion of production in the November to May period. Thus Eustoma is now readily available year-round by using selected cultivars growing in appropriate climatic locations. In warmer areas, high quality flowers (with stem 80 cm +) can now be produced in two flushes from November to June using selected cultivars sown in June and July. But, due to high temperatures, seedlings rosette and stems do not elongate or bolt. To overcome this problem, various methods have been attempted such as artificial cooling of seedlings at night, cultivating seedlings in the cool highlands and shipping them to northern areas. We devised an artificial cooling method to be used on rosetted seedlings. In this way, seeds are greenhouse sown and raised under (naturally) high temperatures (day 25-30°C and night 20-25°C) for 35 to 45-d in order to develop a seedling rosetted. Then these rosetted seedlings are transferred to a cool store at 12±1°C which is illuminated with 5-10μmol/m²/s commencing at the four-leaf stage for 4-weeks. With this technique the rosette state is broken. With suitable cultivars this precise technique guarantees success and uniformity flowering and consequently it is rapidly being commercially adopted.

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For analyzing the effect of dissolved O₂ concentration on root water uptake in hydroponics, the stem base water flux in cucumber plants (Cucumis sativus L.) was measured by heat flux control method (HFC) in “a” newly developed system for controlling dissolved O₂ concentration. At an air temperature of 25°C, a relative humidity of 70%, a PPFD of 300μmol m^-2 s^-1 (a photoperiod of 12 h) and a root temperature of 25°C, dissolved O₂ concentration was controlled at set values of 0.01, 0.10 and 0.20 mM with an accuracy of ±0.005 mM. At each dissolved O₂ concentration, the water uptake rate drastically increased by lighting the plant, and water uptake reduced in proportion to decrease in dissolved O₂ concentration: Water uptakes per day at 0.20, 0.10 and 0.01 mM were 235, 186 and 164 g, respectively. This fact suggests that root water uptake in hydroponics is depressed at lower dissolved O₂ concentrations by change in membrane permeability of root cells through respiration-dependent processes.

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Young rice plants were solution-cultured in artificially illuminated growth cabinets under combinations of 35 (ambient) or 70 (high) Pa atmospheric CO₂ and 0.6, 6, 60 or 600μM phosphorus (P) nutrition with other growth conditions of 12-h day (450μmol m^-2 s^-1 PPFD) /12-h night cycle at 28/23°C and about 60% RH. Generally, the growth and dry matter production were promoted by high CO₂ and the effects were enlarged with elevating P level up to 60μM but the highest P (600μM) decreased the CO₂ effects. At the lowest P (0.6μM), the root growth was substantially promoted at the sacrifice of shoot growth. The net assimilation rate (NAR) was largely promoted by high CO₂ but not by P nutrition. The high CO₂ decreased the leaf weight ratio (LWR), which indicated the relative promotion of dry matter partitioning to organs other than leaves. The mineral nutrient (P, K, Ca, Mg) content was also decreased by high CO₂, probably because of the dilution effect of carbohydrate accumulation. The P use efficiency in dry matter production decreased with increasing P levels but high CO₂ ameliorated the effect of P. It was concluded that the growth of rice plants in poor P conditions would be ameliorated at high CO₂ levels. However, substantial amounts of P should be applied for their full growth.

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A method for application of the exergy concept to the optimization of greenhouse heating systems using the heat generated in composting is discussed. It was found that exergy analysis helps to decide the optimum quantitative operating conditions under which not only the composting reaction most properly occurs but also the greenhouse heating process most effectively operates. According to the calculated results obtained for the heating process of a greenhouse on a small scale in the Hokuriku district, it was theoretically found that the optimum temperature of heat source is about 333 K and is almost equal to the optimum temperature for composting, in so far as we use a heat exchanger in which exergy dissipation due to friction is less than 10 times as much as the exergy dissipation due to friction during aeration through the compost bed.

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Three dimensional distribution of leaf tip angle and three dimensional outline of shape of tomato plants were measured by the method of image measurement based on textural features proposed by Shono (1995), and its availability was verified. An algorithm for simplifying the complicated information for efficient transaction was proposed. From discussions on the results, the following conclusions were derived. (1) Three dimensional distribution of leaf tip angle and three dimensional outline of shape of tomato plants can be measured separately fairly well especially in upper and younger regions. (2) Because crowded leaves in lower and older regions have different tendencies in leaf tip angle between inner layer and outer one, three dimensional measurement is very effective for measuring the proper condition of leaf tip angle. Principal component analysis was applied to obtain understandable indices. The analysis is helpful in understanding the meaning of the shape information.

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The pneumatophores of Avicennia and Sonneratia species photosynthesize and the photosynthetically generated O₂ is used for the respiration in the roots in subsoil. To understand the radiation environment of the pneumatophores, we measured solar radiation on the vertical surface (R_v) in the water with dye films. The R_v averaged over the daytime at a depth of 30 cm was similar to the light compensation points in the pneumatophores. From this result, it can be supposed that the photosynthesis nearly compensated the respiration at a depth of 30 cm and supplied O₂ to the roots in subsoil at shallower places, even when the pneumatophores were submerged in the daytime.

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