土壌病原菌の土壌生態学的研究 : 第5報 根頭癌腫病菌に対する土壌諸要素の影響  [in Japanese] Soil-ecological Studies on the Soil-pathogens : 5. Effect of various Soil-factors on the Growth of Agrobacterium tumefaciens (SMITH et TOWNSEND) CONN  [in Japanese]

多犯性土壌病原細菌Agrobacterium tumefaciens(SMITH et TOWNSEND)CONNを対象として土壌環境諸要素の影響を調査した.その結果を要約すれば次の通りである.1.本細菌は砂質土壌において, 良好な生育をなし, 粘土含量の増加と共に生育が減退し, 粘土のみの場合は, その生育が著しく抑制される.2.本細菌の土壌中での生育の最適温度は25℃であり, 最高および最低温度は, それぞれ40℃と5℃であつた.3.本細菌は土壌湿度40%〜100%の範囲で生育し, 特に70%〜80%において最良の生育を示し, 40%以下では急激に生育が減退し, 100%でも生育はかなり減退した.4.本細菌はpH6.0〜8.4の中性ないし弱アルカリ性で最適の生育をなし, 最適酸度はpH6.8と見なされる.5.有機物の土壌への添加は, 本細菌の生育を著しく助長するが, 無機添加物の添加は, 尿素以外は, 本細菌に対して抑制的に作用するものと思われる.

The present paper is the results of experiments on the influences of soil environmental factors on the growth of Agrobacterium tumefaciens (SMITH et TOWNSEND) CONN, which attacks various kinds of Solanaceous plants in Japan. The results obtained indicate that, 1) This bacterium well developed in the sandy soil and its growth decreased with the increase of content of clay. Its growth was remarkably disturbed in the clay only. 2) The optimum soil-temperature for this bacterium was 25℃, the highest and the lowest temperature was 40℃ and 5℃ respectively. 3) This bacterium developed between 40% and 100% of water content, especially well between 70% and 80%. Its growth decreased rapidly below 40%. 4) This bacterium developed well between pH 6.8 and pH 8.4,the optimum soil reaction was pH 6.8. 5) Adding the organic materials to the soil helped the development of this bacterium, but the inorganic materials except urea seemed to disturb its growth.