The shoot primordium is a suitable inoculant for large scale culture of shoots comparing with the shoot. itself. A culture method of multiple shoots starting from the shoot primordium was established. The influence of scale up conditions on the growth of multiple shoots originating from the primordia was also investigated.
Shoot primordium of Stevia rebaudiana has been induced and maintained in modified MS liquid medium containing NAA and BA. The primordia grew constantly by about 7 times in 1 month in the liquid shake culture. The multiple shoots were then induced efficiently from the primordia by eliminating the growth hormones from the MS medium. They grew constantly by about 20 times in 1 month in the liquid shake culture. The growth of shoots in culture vessels of different sizes, 0.3 l (flask), 6 l (jar fermentor) and 500 l (bioreactor), were compared by inoculating the primordia at a fixed density of about 10 gl^-1. The shoots grew actively to fill up culture vessels within a month, and the final weight of shoots per unit volume of medium was similar in each culture vessel. This result strongly suggests that multiple shoots can be mass propagated in a large scale without affecting the culture efficiency.

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Development of an efficient system for shoot mass propagation through the entrapment of shoot primordia was investigated on Stevia rebaudiana. Shoot primordia of Stevia rebaudiana could be trapped into cubes of reticulate form matrix of loofah, sponge of Luffa aegyptica, when the primordia were cultured in a rotary culture system (flask scale) or in the drum type jar fermentor system in the presence of the cubic matrices. The shoot primordia grew to form uniform clumps staying in loofah matrices and the growth was stimulated by the entrapment compared to the control culture without the matrices. Shoots were efficiently induced from the entrapped clumps of primordia under subsequent static culture condition and were acclimatized successfully without removing the matrices.

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As the first step of the studies on the effect of the physical and chemical properties of electrolytic water on the growth of soilless culture plant, the five kinds of electrolytic water such as low and high cathode water, low and high anode water, and mixed water which is the volume ratio of cathode water vs. anode water is 1 : 1 were obtained by two electrolytic voltages, and their properties were measured and evaluated.
The measured properties were as follows : pH, oxidation reduction potential (ORP), electric conductivity (EC), surface tension (ST), and dissolved oxygen (DO). The relationships between electrolytic voltage and pH or ORP, and between each pH and ORP of above mentioned five kinds of electrolytic water were evaluated, and then the variances of the values of pH and ORP of each electrolytic water were measured.
The values of pH and ORP of cathode water were increased, those of anode water were decreased and those of mixed water were slightly increased with increase of the electrolytic voltage, respectively. Each relationship between pH and ORP of the three kinds of electrolytic water was as follows : the ORP of anode water was linearly decreased, that of cathode water quickly decreased till halfway since slightly decreased, and that of mixed water early and quickly increased afterwards slightly increased and again quickly increased at last with increase of pH, respectively. Both values of pH and ORP were early and steeply varianced but afterwards convergented to those of control (well-water).

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電解水の陽極水, 陰極水およびその混合水を用いてコマツナを水耕栽培した.電解水の理化学的特性と無機成分を測定し, 生育量と電解水の特性との関係を検証した.
1) pHが4-9の範囲の電解水は, 2-4日でその理化学的特性を失い, 植物への影響力を失った.
2) 播種後10日目まで電解水のみで育苗後, 水耕装置に定植し, 電解水に水耕用肥料を混入した養液で無調整・無交換のまま栽培した場合は, 一部を除き電解水の影響はみられなかった.
3) 電解水中の無機成分は陰極水に陽イオン, 陽極水に陰イオンが多いが, 肥料を混入するとその濃度差は現れなくなり, 無機成分濃度の差により生育に差が生じるとは考えにくい.
4) 電解水に肥料を混入するとpHは6.25付近に揃うので, pHにより生育に差が生じるとは考えにくい.
5) 電解水養液を頻繁に変えることで電解水の特性が継続的に植物におよぶようにすると, 酸化還元電位 (ORP) が高い処理区では生育を抑制し, ORPの低い区では促進効果がみられた.ゆえに, ORPと生育促進および抑制の間には相関関係があると推察される.

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To investigate the effects of the oxidation reduction potentials (ORP) of electrolytic water and its solution mixed manure on the early growth of soilless culture plant, Komatuna was cultured during ten days by using the electrolytic water solutions, which adjusted to the three ORP values in the region of 100-750 mV, and to the almost constant pH of 6.5±0.25.
In the case of the ORP was as high as 700-750 mV, the length and weight of the plant (or seedling) were brightly repressed, but in the case of the ORP was as low as 100-150 mV, they were almost increased. In the case of the ORP was middle value, the length of plant was increased but its weight was slightly decreased.
At both experiments of No. I and II, the electrolytic water solution of low ORP was mainly promoted the growth of top (stem and leaf) of plant, but there were no correlative relationships between the ORP and the leaf number, the root growth, because the maximum leaf length, the fresh and dry weights of top, and the top-root ratio of fresh weight at low ORP were larger than those of control plot.
In the experiment of No. II, each ORP of two cathode water solutions was adjusted to 100-150 mV and 300-350 mV with well-water, respectively, and one solutionwas adjusted to 300-350 mV with anode water. Those three solutions and a control of well-water were mutually compared.
At any experimental plots, the leaf number, both fresh and dry weights of top, and the top-root ratio of fresh weight were increased, namely, the growth promotion effect at top was found, and the growth in a plot adjusted to 300-350 mV with electrolytic water was most promoted the growth.

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The growth tests in Kaiware radish were carried out in both distilled water and city water. The results obtained are as follows.
1) Germination of Kaiware radish in distilled water is better than that in city water.
2) The early growth of Kaiware radish in city water is much faster than that in distilled water.
3) City water having half-peak width of ca. 120Hz in the ¹⁷O-NMR spectra is suitable for both germination and early growth of Kaiware radish.

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Mass culture of plant cell and tissues in a bioreactor are widely used for production of plant metabolites or seedlings. Packed Cell Volume (PCV) and Optical Density (OD) are used for off-line measurement, and Electric Conductivity (EC) and pH are used for on-line measurement of growth rate in bioreactors. In these measurement, the samples are derived from a part of a reactor, and these sample may not indicate the actual status of bioreactor, because the growth rate may change in height or radius of bioreactor.
An ultrasonic technique was used to measure the growth rate in a bioreactor.The material used were plant cell of Rice plant (Oryza sativa), and adventive root of Atropa belladonna. The frequency of ultrasonic sensors were 0.5, 1, 2, 3, 5, and 7 MHz. It was found that the attenuation of ultrasonic wave propagated through the bioreactor had linear relation with the growth rate and that the stronger attenuations were measured in higher frequencies. The velocity of waves were almost constant with the growth rate. A simple model using a wave equation was used to simulate the attenuation of ultrasonic wave in the bioreactor, and the results showed good agreement with the experiment. The ultrasonic wave can propagate across the bioreactor, and it seems that the results correspond to the actual status of the bioreactor.

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