ナス種子の発芽誘起には, 発芽温度, GA₃と登熟, 後熟であらわされる種子の生理的状態が密接に関係するが, ナス種子の発芽に対するGA₃の効果は3つの作用に分けることができる.
1) 種子採取後, 後熟をまったく行わない休眠過程にある種子に対する休眠覚醒の効果.
2) 後熟が進行して非休眠過程にあっても, 登熟が不十分なため高い発芽を示さない種子, およびageの進行により発芽力消失過程にある種子に対する発芽誘起効果.
3) 発芽に不適当な高温による種子の二次休眠の誘導を妨げるとともに, 高温下での発芽誘起効果.

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耕地における植被内の変動光については, 十分に明らかにされていないのが現状である.本研究では, 圃場条件下と室内実験によって, 各変動光波形の特徴について比較検討した.得られた結果は下記のごとくである.
(1) 圃場の植被層における自然光下の変動光について, 種々の条件で検討した.それによると, (1) 変動光の強光と弱光間の差は, 日射強度にほぼそった日変化を示した. (2) ミカンの樹冠内では, 変動光の発生している個所は多くなかった. (3) 栽植密度が増大するに従い, 変動光は顕著に現れた. (4) 植被の種類によって変動光の波形に差異がみられ, その原因として植被内の風の運動エネルギーと植被の物理的特性等によるものと考えられた.
(2) 変動光に関する風洞実験から, 各植被 (約20cm高) の変動光のスペクトル密度が一定のレベル以上になる周波数は, 風速1.7ms【-1】1の場合, ナス, ピーマン, アスパラガス, シュンギクは15Hz程度, カブは11Hz程度であり, ネギは約6Hzの線スペクトル状であった.6種の植被についてピーク周波数は弱風 (1.7ms^-1) と強風 (2.5ms^-1) の場合ともに大差はなく, いずれも1.5～5.OHzであった.ピーク値は風速の増大につれて比例して大きくなった.一定のレベル以上のスペクトル密度を持つ周波数域が風速とともに高周波数域へ広がる傾向もみられた.

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The seedlings of sunflower (Helianthus annuus L. cv. Russian Mammoth) were hydroponic-cultured in a controlled environment at 25°C and at 70% relative humidity. Using three band fluorescent lamps (5000 K) as the main lighting source, the PPFD (400-700 nm) was kept at 200, μmol⋅m^-2⋅s^-1, and each additional PFD (700-800 nm) of far-red (FR) irradiation in four experiments, using FR fluorescent lamps, was kept at 107.1, 50.1, 25.6, and 9.3 umol⋅m^-2⋅s^-1, respectively.
According to the additional level of FR irradiation, the fresh weight, dry weight, leaf area and stem length of the seedlings were increased. The stem length was extended greatly by additional FR irradiation, and leaf/stem dry weight ratio was also changed. Eight days after the treatment by FR irradiation, the stem length was extended 3.8 times longer in FR, 107.1, μmol⋅m^-2⋅s^-1 treatment in comparison with the 9.3μmol⋅m^-2⋅s^-1treatment, and leaf/stem dry weight ratio was 5.8 to 2.7.
It was found that stem extension and leaf/stem dry weight ratio could be controlled artificially by the level of the additional FR irradiation. As a result, it indicates that the evaluation of FR irradiation may be useful in designing the lighting conditions of plant factories or in atria.

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An experimental plant factory using flourescent lamps was developed, and its performance, productivity, and power consumption were investigated through cultivation tests of lettuce. The results are as follows.
(1) Using a close illumination method with fluorescent lamps, three stages of the planting bed could be vertically stacked for cultivation of seedlings and two stages for growth, and the compact cultivation system could be realized. When all 42 flourescent lamps of 110 W/stage were illuminated, the mean light intensity on the floor was as high as 650μE/m²/s (45 klx) .
(2) The environmental conditions were adjusted by an ON/OFF control using a programmable controller. The air temperature, relative humidity, CO₂ concentration, electric conductivity of hydroponic solution and pH were found to be regulated in the range of, respectively, 25±0.5°C in light period/20±0.2°C in dark period, 70±5%, 900±50 ppm, 1.3± 0.1 mS, and 5.5±0.5 under conditions of light intensity of 330μE/m²/s, lighting time of 16 hr/day, and wind velosity of 0.5 m/s.
(3) The lettuce (Kuroha and Greenwave) grew to weigh more than 75 g in 29 days, and the production of an experimental facility was 120 stocks/day. At this time, the seedling weighing about 0.25 g grew acceleratedly, and the fresh weights increased by about 40 times in 9 days.
(4) The daily average power consumption throughout the year was about 300 kWh (45% for lighting, 35% for air-conditioning, and 20% for others) . The power consumption for lighting and the total power consumption for the production of lettuce was found to be about 1.1 and 2.5 kWh/75 g-fresh weight respectively, and energy was saved as compared with the conventional apparatus. However, about 75% of total energy was spent on the growth unit, so to reduce the production cost it seems effective to cut the input of energy and equipment to the growth unit, and invest particularly in the seedling unit which contributes greatly to growth promotion.

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These studies were carried out for the development of non-invasive and continuous moni-toring technique of plant growth in the plant factories.
In this kind of facilities, the environmental factors such as ambient temperature, relative humidity, light intensity, pH of nutrient solution are measured and reported with high accuracy. But, data on plant growth are not measured almost or at all even nowadays.
We have, therefore, tried to apply the method of image processing and obtained sufficient results. They are summarized as follows.
(1) We have developed the plant growth monitoring system by image processing with a personal computer for the plant factories.
(2) The leaf area was regarded as the most useful index of vegetable (lettuce) growth as a non-invasive method.
(3) It was linear to the fresh weight with high coefficient of correlation (>0.95) .
(4) The scheduled harvest was achieved by these techniques.

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