Morphological and Physiological Studies on Nodule Formation in Leguminous Crops : IV Factors determining the site of first infection cells in nodule formation

[摘要] In the previous paper, the author classified seventeen species of Leguminous, crops into three types according to the initial position of the nodule formation. namely, II-A. type; nodule originates in the outer layers in primary cortex. II-B type; in the inner layres of primarly cortex, and II-C type; the axil of lateral root. The present experiment was carrid out to clarify the relation between the site of first infection cells in different types and the physiological differentiation of host tissues as well as the fermentative characters of each nodule bacteria on the cultural mediums, especiallly, the minimum amount of carbohydrates required for the maximum growth of bacterias. The results are as follows. (1) The relation between the physiological differentiation or the gradients in the primary bodies of host tissues and the location of the first infection cell in host tissues. The distributive pattern of reducing sugars, protein and other nitrogen compounds, and fatty matters in the primary cortex and the pericycle was sames in all plants investigated. The primary cortex cosists with undifferentiated primary parenchyma cells and the cortical cells are identical in general histological appearance but the physiological differentiations were observed within the primary cortex. In general, the reactions of Fehling's solution and Ozazon method for reducing sugars, Bensly's Millon and Ninhydrin reaction by Berg's; for the protein and nitrogen compounds, Sudan Black Alcohol method for fatty matters were stronger at the inner layers of primarly cortex, especially, at the opposite side of the protoxylem points with a progressive decrease towards the outer layer. This results indicated that the nodule formation in II-A type plants took place at where reaction of reducing sugars was most week in primary cortex, in II-B type plants it took place at where the stronger reaction of reducing sugars was shown and in II-C type plants at the pericycl cell showing the stronger reaction for reducing sugars. (2) The relation betweem the sugar requirement of nodule bacterias and the location of the first infection cell in host tissues. The nodule bacterias of different types differs with the minimum level of sugars in the cultural mediums. The minimum concentrations of sugars in AO medium (M. R. N. RAGGIO, 1958) with manntol as carbon source for each bacterias are as follows, 0.01∼0.02 gr/l for Rhizobium Japonicum (II-A type), 0.2∼0.4 g/l for R. Leguminosarum (II-B type), and 0.1∼0.2 g/l for R. Sp (II-C type) respectively.

[学科分类] 农业科学（综合）