A method for measuring the firmness of cherry tomatoes based on the displacement of their surface caused by the spraying of compressed air was studied. The main results were as follows : 1) If the air pressure, the inner diameter of the nozzle for spraying the compressed air, and the distance between the tip of the nozzle and the fruit surface were given suitable values, and if the fruit was secured so that it would not shake, the surface of the fruit would be only slightly deformed, and the displacement of the fruit surface could be measured precisely ; 2) The coefficient of correlation between the measurements obtained by this method and measurements obtained by a commercial fruit firmness meter was about -0. 95 ; and 3) When the displacement was calculated from the value that was measured by a laser displacement sensor, 0 mV was the optimal standard value. Thus, it appears that this method can be used to measure the firmness of cherry tomatoes.

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施設花卉の代表であるバラはきわめて病害に弱い.われわれは切り花バラの苗木生産で問題となる重要病害の一つである, バラ黒星病に対する抵抗性育種の一環として, 種間雑種集団を育成し, 遺伝性の確認, 高度抵抗性個体の探索, 抵抗性個体の開花特性の調査, および倍数性について調査した.栽培バラとRosa rugosaとの交配で, 両親のいずれよりも高度の抵抗性を示す雑種個体を得た.Rosa rugosaの特徴である茎に密生する細かな棘は, 雑種個体に普遍的に発現したが, 高度抵抗性を備えながら, 棘の少ない雑種個体を得ることができた.フローサイトメーターを用いて, 得られた雑種個体集団の倍数性を調べたところ, 交配に用いた両親種・品種の示すピークの中間に位置したので, 交配は適正であった.また, 葉が3倍/6倍の倍数性キメラ, 花が純粋に3倍性を示す興味深い雑種が含まれていることが分かった

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Research has been conducted into the relationship between plant growth and changes in the electric potential of leaves. We previously investigated correlations between plant nutritional state and leaf potential, and in tomato plants, determined the specific frequencies at which nutritional changes alter the leaf electric potential. We demonstrated that nutritional diagnosis may be possible by measuring changes in leaf electric potential. The leaf potential of nitrogen-deficient tomato plants increased at 13 and 20Hz, the potential of magnesium-deficient plants increased at 20, 13 and 5Hz, and the potential of phosphorus-deficient plants increased at 30 and 20Hz.
In the present report, we describe the relationship between nutritional state and leaf potential in lettuce. Peak electric potential in lettuce leaves occurred at 16-20Hz. Peak electric potential increased in both nitrogen-deficient plants and plants grown in nutrient solution containing an excess of phosphorus. Lettuce growth was improved when N concentration in the fertilizer was increased and P concentration was decreased. Because growth is negatively correlated with leaf electric potential at 18Hz, the nutritional state of lettuce may be evaluated by measuring leaf electric potential at 18Hz.

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Effect of ORC (oxygen release compound) on organogenesis in PLB (protocorm-like body) cultures of Cymbidium finlaysonianum was examined. Proliferation of PLB was promoted by addition of ORC at concentrations over 30 mg/l. Addition of ORC to culture medium resulted in a significant increase in shoot numbers developed from PLBs. Number of shoots were increased 1. 8 fold compared to that after control treatment.

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Protocorm-like bodies (PLBs) of Cymbidium finlaysonianum Lindl. were explanted on modified Kano's medium (Hyponex medium) supplemented with two kinds of chitosans. Within 8 weeks of culture, proliferation of protocorm-like bodies (PLBs) and differentiation of shoots from PLBs were observed. Explants were cultured on medium containing chitosans formed mass of PLBs followed by differentiation of shoots. The number of PLBs and the number of shoots from proliferated PLBs were significantly increased by application of chitosans.

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今回は舞茸の子実体の周囲温度に着目し, 一般に生産現場で設定されている温度近辺 (16～22℃) について生体電位の温度依存性の実験を行った.その結果, 18℃において大きな生体電位反応が観測された.今後はさらに例数を増やして再現性を得るとともに, 生体電位の変化と形態形成との関連性についても検討を進める予定である.

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ソバの試験管内交雑育種が可能かどうか検討した.試験管内種子発芽体から切除したシュートから誘導された花芽の子房と花粉および圃場植物由来の花芽の子房と花粉を組み合わせて掛け合わせた.試験管内花芽由来子房と圃場花芽由来花粉を掛け合わせると, 組み合わせの2%で第2世代植物が試験管内で得られた.試験管内で誘導された花芽原基を試験管外に引き出し開花させ, 人工受粉させたところ, 正常な受粉が起こり, 試験管内花芽由来子房と花粉の試験管内受粉率の低い原因として, 培養環境が生殖機能を低下させる可能性が考えられた.試験管内第2世代植物は試験管内大量増殖が可能で, 品種あるいは系統確立までの育種操作が試験管内で実証された.圃場で栽培した試験管内第2世代植物は交雑可能で生殖能の正常な植物と考えられた.また, 第2世代植物からの試験管内花芽の誘導および圃場花芽由来花粉との試験管内交雑も可能で第3世代植物が得られ, 継続的な試験管内交雑が可能と考えられた.試験管内での植物の交雑育種について言及した.

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