The effects of solutions for pretreatment and length of low-temperature storage period of runners on the plantlet growth were examined in shoot apex culture of strawberry (Fragaria×ananassa D.) . For pretreatment, the solutions (Distilled water, MS liquid medium without sucrose, 1/10 MS liquid medium without sucrose, 30g 1^-1 sucrose solution, 30g 1^-1 glucose solution) were absorbed by runnners for 24 h at 20°C. It was found that solutions for pretreatment and length of low-temperature storage period of runners influence the survival rate of shoot apex and plantlet growth. Following pretreatment with 1/10 MS liquid medium, runners can be stored at low-temperature for 5 weeks without any effects on the survival rate or the plantlet growth.

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The experiment was carried out to determine the environmental factors which could affect the anthocyanin synthesis and sugar content of Cichorium intybus L. var. foliosum. The major pigment of purified aglycone of C. intybus was identified as cyanidin by TLC and HPLC analysis. It was concluded that the anthocyanin synthesis of C. intybus was promoted at low temperature and high light intensity and enhanced in the UV-transmission treatment compared to the UV-cut treatment. Furthermore, it seemed that suger accumulation played an important role in anthocyanin synthesis.

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Characteristics of root growth in root vegetables raised in hydroponics were studied. Radish (Raphanus sativus), carrot (Daucus carota) and gobo (Arctium lappa) were cultured with the deep flow culture technique (DFT) or the ebb and flood culture (E & F) technique with or without substrate. Seedlings of which the tap root was straight and had started thickening were transplanted in the hydropoic system. Individuals were obtained in all the crops studied, the root of which attained the size and shape proper to each cultivar. Storage root growth with DFT was rather inconsistent as compared to that with E & F with or without substrate, especially in radish. Increase in both root diameter and length along the root axis contributed to storage root growth of radish, while very little increase in root length was observed in carrot. Root length decreased as root diameter increased during storage root growth of gobo. Increase in root diameter toward the proximal end of carrot storage root was remarkable with DFT, resulting in a spindle shape of the root and was often followed by radial cracking along the axis. This phenomenon was observed also in radish to a lesser degree. Results of present study demonstrated that satisfactory growth of storage root in root vegetables could be obtained in hydroponics, although characteristics of growth were different in several aspects in the three vegetables studied.

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The objective of this study was to clarify the effects of CO₂ enrichment and day temperature on growth, flowering and cur flower quality in Japanese autumnal chrysanthemum ‘Shuhonochikara.’ As the day temperature rose from 15 to 25°C with 15°C night temperature, stem length on the last day of long-day treatment increased; however, weights of stem, leaves and roots decreased. Flowering was the earliest with temperatures between 15°C and 20°C during the long-day period. While under the short-day conditions, the same was observed at 20°C. By enriching the atmosphere with 1000 ppm CO₂, stem length, number of leaves and weights increased compared to the plants in ambient CO₂. The greatest increase was observed in root dry weight (167-200%) . Flowering was advanced by 2 to 4 days and flower diameter also increased by CO₂ enrichment. Under CO₂ enrichment, there was no significant influence of day temperature on the quantitative growth (e.g. weights, number of leaves, and stem length) during the long-day period, whereas, the day temperature had significant influence on the qualitative growth (e.g. length of flower neck and number of tubular florets) . Concentrations of N, Ca and Mg in the leaves and stem of plants grown under CO₂ enrichment were lower than plants under ambient CO₂.

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The present study was undertaken to evaluate the water status and fruit quality of Satsuma mandarin trees (Citrus unshiu Marc. cv. Okitsu wase) affected by changing the nutrient concentration and grown hydroponically from mid-September to harvest. The water potential of nutrient concentration was kept at -0.08 MPa as the control or gradually decreased to -0.43 MPa as the treatment. After the water potential of nutrient solution was lower than -0.30 MPa, both water potential and osmotic potential of leaves and vesicles of fruit gradually decreased as compared with those of control trees. However, turgor of both tissues was maintained at the same value during the treatment. As fruit growth nearly stopped for 30 days after the water potential of nutrient solution was lower than -0.30 MPa, the fruit size of high nutrient concentration was smaller than that of the control. The content of sucrose, fructose, and glucose of fruit grown under high nutrient concentration were significantly greater than those of the control, but acidity showed no differences in both treatments. The application of hydroponic culture indicated that it is possible to control plant water status, fruit growth, and to increase the sugar content of fruit by an increase in the nutrient concentration.

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The hydroponic technique for sweetpotato cultivation was used under field conditions in a wet lowland. A plastic porous tube was placed in a soil ridge for aeration treatment. Water depth between the ridges was kept at 20 mm throughout the growing period in order to imitate the wet soil conditions in tropical and subtropical lowlands. The growth characteristics and yield of sweetpotato grown with the aeration treatment were compared with those grown in a conventional ridge as a control. The dry weight of above-ground parts was 1.8 times greater in the control than in the aeration treatment, while the dry weight of sub-ground parts was 3.1 times greater in the aeration treatment than in the control. The dry weights of stem and leaf, main stem length and leaf area were less in the aeration treatment than in the control. The dry weight of tuberous roots was 4.4 times greater in the aeration treatment than in the control, while the dry weight of roots excluding tuberous roots in the aeration treatment was almost half of that in the control. The edible biomass index was 4 times higher in the aeration treatment than in the control. Plants in the aeration treatment had greater edible parts (tuberous roots) and less non-edible parts (stems, leaves and roots excluding tuberous roots) than those in the control.

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The potential traits of photosynthetic and photoautotrophic growth of hairy root derived from co-cultures of Cucumis melo L. with Agrobacterium rhizogenes were investigated. Thirty-two different lines of hairy roots induced from leaf explants of the plant were used to determine the conditions which favor the induction of photoautotrophy. Although all of the hairy root lines remained white under dark condition, some of them turned yellow green to pale green when incubated in MS medium containing low concentration of sucrose and supplemented with a buffer releasing CO₂. One of the initially heterotrophic hairy root cultures, KMH-18, turned green rapidly, produced chlorophyl, and grew well depending on CO₂ fixation under these conditions.

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Postharvest chervil, a kind of culinary herb, stored at 8.0°C under low light irradiation (LLI: 1μmol m^-2 s^-1 PPFD) with nutrient gel application (NGA) to the cut ends of the stems showed similar changes in chromaticity (L^*, a^*, b^* and ΔE^*ab) values for 21 days of the storage period to that stored at 6.8°C under darkness with NGA. Low light was provided with an array of red light emitting diodes (red LEDs) . Postharvest chervil stored without NGA showed markedly greater values in L^*, a^* and ΔE^* ab after day 9 of the storage than that stored with NGA at 8.0°C under LLI. LLI using red LEDs with NGA proved highly effective for preserving the visual quality of postharvest chervil during low temperature storage.

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Air currents in plant tissue culture vessels were visualized using fine particles of metaldehyde ( (C₂H₄O) ₄) as tracers. Movement of the tracers was monitored with a video camera. The video image was analyzed to determine patterns and speeds of the air currents. An upward air current with an air current speed of 12 mm s^-1 was observed in the central region and downward air currents with an air current speed of 7 mm s^-1 was observed along the inside walls in a Magenta-type polycarbonate vessel (370 mL in volume) with a 10-mm-tall potato plantlet. It was proved that air currents were retarded in plant tissue culture vessels.

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