Eggplant (Solanum melongena L., cv. Senryounigou) plug transplants were grown for 17 days in a closed-type transplant production system at photosynthetic photon flux on the tray surface of 0, 100 and 350 μmol m^-2s^-1 on days 0-3, 4-6 and 7-16, respectively, air temperature of 30/ 20°C, (photoperiod/dark period) CO₂ concentration of 1000 μmol mol^-1 (photoperiod), relative humidity of 80/100% (photoperiod/dark period) and photoperiod of 16 h d^-1. The electric energy consumption per transplant was 0. 35 MJ (0. 1 kWh) and its cost was 1. 4-1. 5 Japanese Yen. The period required for transplant production was about 2 weeks shorter in the closed-type transplant production system than in the open-type transplant production system (i.e. the greenhouse). The amount of consumed water per tray area in the closed-type transplant production system would be reduced from 65. 8 to 12. 3 kg m^-2 by reusing dehumidified water for irrigation. These results show that the closed-type transplant production system is feasible for commercialization.

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Photosynthetic rate, relative growth rate and vitaminC contents were measured in lettuce cultivated under red and blue lasers and the results were compared with those cultivated under light emitting diodes (LED). It was found that lettuce grew fairly healthily under red laser diode (650 nm) and blue laser (442 nm) with R/B ratio 10. However, both photosynthetic rate and growth rate rather diminished compared with LED cases. As for vitaminC contents, the result was about the same as LED cases.

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A punching mechanism was developed for placing seeds of leaf vegetables directly into precut cells of urethane mat in hydroponic seedling production of leaf vegetables. The mechanism has twelve punchers, which are in the form of a hollow cone to penetrate into urethane mat for seed placement. The mechanism was attached and synchronized to the conventional vacuum seeder. When punchers penetrate the urethane mat, seeds are discharged from nozzles and delivered to punchers through tubes. Seeds of mustard spinach were used for the performance test. Punchers with outer diameter of 3.0 mm and cone index angle of 10 degrees could successfully penetrate into pre-cut cells of urethane mat. The punchers accurately placed the seeds at pre-determined punching depth of 3.0 mm with seeding efficiency of 96.5%.

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The concentration of dissolved oxygen in a culture solution is one of the most important environmental factors affecting the growth of the tops and roots of plants under hydroponic culture. In particular, the roots of tomatos readily absorb oxygen in the solution, and are thus sensitive to the concentration of dissolved oxygen. Thus, the effects of dissolved oxygen concentration on the morphology and growth of roots, water uptake rate and nutrient uptake were investigated. In hydroponic culture, the supply of dissolved oxygen is essential. Previously, we reported that supersaturation of dissolved oxygen in culture solution promoted the uptake of phosphate. In the present study, we found that supersaturation of dissolved oxygen in culture solution low in nitrogen and phosphate led to an increase in plant height, fresh weight of stems and leaves and root weight. It also increased the phosphorus concentration in the sap, stems, leaves and fruits of tomato plants.

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We have developed a new image analysis system, capable of quantitative analysis of two aspects of chlorophyll a fluorescence ; i) the changes in intensity of chlorophyll fluorescence during dark-light transitions by the induction method, and ii) the chlorophyll fluorescence quenching by the saturation pulse method. With this system we analyzed the effects of an herbicide on the photosynthetic activity of Phaseolus vulgaris L. leaves. Furthermore, stomatal conductance and assimilation rate were measured with a diffusion porometer.
Results showed that the photosynthetic injuries caused by the herbicide were detected by both fluorescence measurement methods. These injuries were also detected with the porometer as a decrease in stomatal conductance and assimilation rate. Information obtained by the induction method was effective for determining the site in the electron transport system which was damaged by the herbicide. The saturation pulse method could analyze the photosynthetic injuries more quantitatively than the induction method. However, the saturation pulse method required an evenly distributed high level of photosynthetic active radiation (PAR), which makes it difficult to apply to a large leaf area. In contrast, the induction method did not require such a high level of PAR for measurements, and was easier to use for a large leaf area. Consequently, simultaneous use of the saturation pulse method and the induction method enables detailed diagnosis of injuries of the photosynthetic system.

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秋田県の山林所有者が可能と思われるサクラ挿し木苗植栽優良クローン数の上限は, クローン苗の供給サイドにおいて生産管理できるクローン数 (4ないし5クローン) であった.そこで, 植栽優良クローン数を2～6として, 遺伝的形質の発現率と林地での生存率をともに考慮して期待残存クローン数を試算した.その結果, 1.植栽優良クローン数の下限は, 全滅する確率を5%以下と仮定した場合, 純優良クローン期待生存数xsが1以上となる3クローン以上である, 2.優良クローン植栽数を4とし, 純優良クローンの期待生存率Psが80%以上となる林地に植栽すれば, 2クローン問の比較が可能になる, 3.遺伝形質が優れないと判断されている林地で, 期待生存率P_sの高い林分においては, 優良クローン苗に転換すると, 林分全体の遺伝的改良につながると考えられた.

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This study aims to develop a detecting device of missing seed for precision seeding system on hydroponic seedling production of leaf vegetables. In this seeding operation, seeds were planted by vacuum nozzles into pre-cut cells of urethane mat. It is important to detect whether the nozzles picked seeds or not for improving the seeding performance. Moreover the detection should be done automatically. The detecting device of missing seed using a digital pressure sensor was developed. Seeds of mustard spinach (Brassica rapa L. var. perviridis) and Chinese cabbage (Brassica rapa L. var. pekinensis) were used for the performance test of the detecting device. The detection level for setting the pressure sensor was determined and selected at 574 and 569 KPa to detect missing seed of mustard spinach and Chinese cabbage, respectively. The detecting device ould detect the missing seeds and compensate for the missing seeds without using any supplementary seeder. The average seeding efficiency was improved from 96. 5 to 99. 8% and from 97. 3 to 99. 6% for seeds of mustard spinach and Chinese cabbage, respectively. The number of missing cells per ten urethane mats was much reduced from 105 to 6 and from 81 to 12 for seeds of mustard spinach and Chinese cabbage, respectively.

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The forms of Fe introduced into spinach (Spinacia oleracia L., cv. Lead) and lettuce (Lactuca sativa L., cv. Red-fire) by soaking the roots in 100 mg L^-1 ammonium ferric citrate solution for 9 hours (spinach) or 6 hours (lettuce) and their changes during storage for 7 days were determined. After soaking, the Fe content in the leaf blade of spinach and in the leaf of lettuce were 9.9 times (8.23±1.03 mg/100 g FW) and 2.9 times (2.63±0.23 mg) higher than that of the control, respectively and no foliar injury appeared in either plant. The sum of the ratio of water-soluble Fe and exchangeable Fe contents (the amount capable of absorption by the human body via digestion) to total Fe content was about 60% in spinach and about 57% in lettuce. The contents of water-soluble, exchangeable, HCl-soluble, and HCl-insoluble Fe changed negligibly during the storage at 4°C. During the storage at 25°C, these contents hardly changed in spinach, whereas the content of the water-soluble Fe in lettuce slightly decreased.

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The effects of 2, 4-dichlorobenzoic acid (DCLBA) on the number of cucumbers (Cucumis sativus L.) harvested were evaluated by split-root system hydroponic culture. DCLBA (10μmol·liter^-1) in the nutrient solution severely damaged the roots by disrupting the integrity of epidermal cells, and remarkably inhibited the uptake of NO₃^-, H₂PO₄^- and ^Κ+ ions. As a result, DCLBA significantly inhibited the number of cucumbers harvested. Supplementation of the nutrient solution with activated charcoal in one side pot recovered the inhibition especially for the uptake of nutrients, and partly recovered the harvested fruit number per plant compared to that without charcaol. These results indicated that DCLBA affected the uptake of nutrients, and inhibited the growth of young fruit after adsorption from roots.

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胚培養の手法を用い, コムギの胚を養分やpHのコントロールされた精製水区 (A), 岩石浸漬区 (B), 湧水区 (C) で育て, 生育状況を調査することにより, 水の化学的組成の変化が植物の生産に及ぼす影響の解明を, 本実験の目的とした.
1) 胚の生育率を調べた結果, B区およびC区はA区に比べ高い生育率を示した.
2) 子葉形成率において, B区およびC区はA区に比べ高まる傾向を示した.また, そのパターンは類似していた.
3) 草丈および最大根長において, 平均伸長の比較の結果, B区およびC区はA区に比べ伸びの良いことが分かった.
4) 浸潤法により各試験区での気孔開度を測定した結果, B区およびC区での気孔開度は大きく, 気孔開度が栄養吸収量等の違いに影響し, 生育量の違いとなると推察された.
5) 以上の結果より, 培地に岩石を浸漬することによる効果は, 分析した特定のミネラルの影響ではなく, 未分析の微量元素の影響が推察された.

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