Shoot multiplication and plantlets regeneration were achieved from single-nodal explants (with two unfolded leaves) of mature trees of Lagerstroemia speciosa Pers. and Lagerstroemia thorellii Gagnep. through in vitro culture. Nodal explants directly produced multiple shoots when cultured on Murashige and Skoog (Physiol. Plant. (1962) 15: 473-497) medium with 6-benzyl amino purine (BAP ; 1.5 mg L^-1) and indole-3-acetic acid (IAA; 0, 1 mg L^-1) . Cuttings, each having a shoot apex and a node obtained from regenerated shoots were cultured on fresh medium for further multiplication, and an average of 17-20 shoots per cutting were obtained. The differentiated shoots were rooted on half strength MS medium with 0.5 mg L^-1 indole-3-butyric acid (IBA) . The effects of different capping systems on growth during the in vitro rooting stage and percent survival of plants ex vitro, the concentrations of ethylene and CO₂ and the relative humidity in the culture headspace of L. speciosa were also studied. In sealed vessels high concentration of ethylene was observed, which was not the case under forced ventilation. In the photoperiod, the CO₂ concentration in the sealed vessels decreased to ca. 50 μL L^-1; while the concentration was higher in the capping systems with natural ventilation and was highest in the vessels under forced ventilation compared to that of the sealed system. The relative humidity was nearly 100% in the sealed vessels and was 89% in the vessels under forced ventilation. The growth (leaf and root fresh and dry mass) and the percent of the survived plants in the ex vitro conditions were highest in the forced ventilation treatment.

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Kidney bean (Phaseolus vulgaris L.) plants were grown at different levels of blue and red light under broad-spectrum radiation over 12 d. Using four kinds of narrow-band fluorescent lamps, blue or red light was increased at the same levels of photosynthetic photon flux density (100μmol m^-2 s^-1) and red to far-red photon flux ratio (R: FR; 1.1) . Increases in both blue and red light caused increases in total dry matter, but also quite different dry matter distribution. Increasing blue light did not have a significant influence on leaf area but caused a large decrease in stem length. On the other hand, increasing red light caused both increases in leaf area and a small, but consistent, increase in stem length. The data suggest that increases in total dry matter are due to increases in dry matter production per unit leaf area in the case of increasing blue light, and on the other hand, due to increases in leaf area in the case of increasing red light. Besides the growth response caused by R : FR, the results indicate that increases in blue light cause great inhibition of stem extension and thickening of leaf, while increases in red light at constant R : FR accelerates both stem extension and leaf expansion without modifying leaf thickness.

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Increasing blue light and decreasing R : FR with supplementary far-red light affect morphogenesis, dry matter production and dry matter partitioning to leaves, stems and roots. In this study, the combined effects of the two spectral treatments were examined in kidney bean (Phaseolus vulgaris L.) grown under the mixture of four different narrow-band light sources. In addition, because the leaf and stem growth are accelerated by increasing red light (600-700 nm) in proportion to far-red light (700-800 nm) while keeping R : FR constant, this study was conducted to determine whether red light or far-red light causes the acceleration of growth. Increasing blue light (400-500 nm) and decreasing R : FR only interacted on stem extension. The results illustrated with figures suggest that blue light amplifies or attenuates the acceleration of stem extension caused by decreasing R : FR. On the other hand, increasing red light with constant far-red light had no influence on leaf expansion or stem extension while R : FR increased. Because the acceleration of leaf and stem growth is caused by increasing either far-red light or both red and far-red light in our environmental conditions, the stimulative effects on leaves and stems seem to require increases in far-red light rather than red light.

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Effects were investigated and compared of spraying the following three kind of water on the severity of powdery mildew (Sphaerotheca fuliginea Pollacci) infection and on the percentage of leaves with a leaf burn-like physiological disorder in cucumber (Cucumis sativus L. cv. Sharp7) grown in a glasshouse: well water (WW), electrolyzed anode-side water (AW) obtained by electrolysis of dilute aqueous KCl solution (ca. 0.1 g L^-1), and pH-available chlorine concentration (ACC) -regulated water (RW) prepared with HCl and NaClO solutions so as to give the similar values of pH and ACC as the AW. Values of pH, ACC and oxidation-reduction potential (ORP) of the AW and RW were about 2.7, 33 ppm and 1150 mV, respectively. One hundred milliliters of each water was sprayed to all expanded leaves on 28 Oct., 31 Oct. and 4 Nov., once a day. The disease severity decreased markedly after the first spray of the AW and RW followed by a gradual decrease by the subsequent two-times sprays, while it steadily increased in the non-treated control (no spray) and WW treatment. The disease severity on 7 Nov. was significantly (p<0.01) low in the AW and RW treatments as compared to the control and WW treatment. On the other hand, spraying the AW and RW caused a leaf burn-like physiological disorder on some leaves and around 70% of leaves showed the disorder on 7 Nov., while no physiological disorder was observed in the control and WW treatment. The results indicate that the AW can be an alternative to chemical fungicides for powdery mildew in cucumber. However, it is necessary to find out a countermeasure against the physiological disorder caused by spraying AW. The results also indicate that it would be valid for use of a RW as a quasi-AW in experiments to clarify the quantitative effects of pH, ACC and ORP of an AW on crop disease control and occurrence of a leaf burn-like physiological disorder.

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Flowering of morning glory (Pharbitis nil Choisy) occurs during the summer season in Japan. This species is well-known as a typical short-day plant. It is, however, not clear why morning glory flowers in summer season under long-day conditions. To answer this question, we analyzed the seasonal changes in the spectral characteristics of solar radiation and found that the ratio of blue component to photosynthetically active radiation increased in summer and decreased in winter, whereas the reverse held for green, and that of red did not undergo much changes throughout the year. In the present study, we investigated the effect of light quality on flower-bud formation in morning glory (cv. Murasaki), using monochromatic lights. Flowerbud formation occurred much earlier under blue light than either green or red light. It was accelerated by increasing the irradiance of blue light and the ratio of blue light to green light. We suggest that the seasonal changes in spectral composition of solar radiation, particularly the rate of blue component, can be one of the factors in controlling the flower-bud formation of morning glory.

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The growth periodicity of Allium triquetrum plants grown outdoors was assessed. Simultaneously the effect of temperature on initiation and development of flower buds was investigated. The first inflorescence initiated in mid-October and bloomed in mid-March of the following year. When bulbs were stored at different temperatures from August 2 to October 2, the optimum temperature for flower bud initiation and subsequent differentiation was 15°C. But bulbs stored at 5 and 10°C bloomed earlier. The longer scapes were obtained when bulbs stored at 10°C for 2 months were grown in the greenhouse kept above 10°C. Bulbs stored at 5 or 10°C for 2 months from early August and grown in the greenhouse kept above 10°C produced flowers with longer scape in late December.

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