Studies on the Translocation of Assimilated Subsuances Among the Culms of Paddy Plant. : II. On the effects of removing ears or leaves of some culms within a hill at the heading stage on the ripening of each culm of paddy plant.

[摘要] In order to clarify the compensatory translocation of carbohydrates occurring among the culms of paddy rice plant after heading, the panicles or leaf-blades of those culms (e. g., the main culm, all the primary culms, all the secondary and tertiary ones, or the entire culms) were removed at the heading stage, and after ripening of the respective culms, the grains of each panicle were counted by assorting them into three groups; (1) unfertilized grains, (2) incomplete ones, and (3) complete ones (with specific gravity of more than 1.08 each). The grains (1) and (2) are hereinafter referred to as "waste grains". Complete grains (3) were hulled and their 1, 000 kernel weight was taken. Special attention should be directed to that per-hill paddy rice plants used for this experiment consist of the main culm (one), 7 primary culms, 14 secondary ones, and 4 tertiary ones. Our test resuls are summarized as follows; (1) Removing of panicles of some culms within a hill gave a favorable influence on the ripening of remaining untreated culms, resulting in the decrease of their waste grains. In contrast to this, removing of leaf-blades of some culms within a hill gave unfavorable influence on the ripening of the remaning untreated culms, resulting in the increase of waste grains. For instance, the removing of panicles or leaf-blades of all the primary culms gave almost the similar effects not only on the ripening of the main culm and the secondary culms but also on the ripening of the tertiary ones. The number of waste grains decreased by half by removing the panicles of the primary culms, and increased nearly double by removing their leaf-blades. Removing of the panicles or leaf-blades of all the secondary and tertiary culms gave also almost the similar effects on the ripening both of the primary culms and the main culm, and the number of waste grains decreased nearly by half due to removing of the panicles, and increased nearly double due to removing of the leaf-blades, Moreover, the same effect wass also brought on the upper primary culms not having their own secondary and tertiary ones. (2) The ripening of those culms of which leaf-blades were removed was also affected by other culms of which leaf-blades were not removed. In case where the leaf-blades of the main culm alone were removed, its waste grains decreased to less than the half, as compared with those of the main culm in the plot in which leaf-blades of all the hill were removed. In case where the leaf-blades of all the primary culms were cut, thier waste grains decreased nearly by half, comparing with those of the primary culms in the plot in which leaf-blades of all the hill were removed. And in case where the leaf-blades of all the secondary and tertiary culms were removed, their waste grains were larger in number than those of the above two cases, but the significant differences were found evidently between the number of the waste grains of the culms of which leaf-blades of all the hill were removed and that of the waste grains of the culms of which the leaf-blades of the secondary and tertiary culms were removed. The varation of such differences can be ascribed to the ratio between the number of the culms of which leaf-blades were removed and that of the culms of which leaf-blades were not removed. (3) In case where the so-called waste grains showed increase or decrease in the number as given above, the number of unfertilized grains roughly showed proportionate changes with at of incomplete grains. However, when it showed particularly great increase in the number of waste grains, it showed a relatively great increase in the number of unfertilized grains. (4) No great differnces were found in 1, 000 kernel weights of complete brown rice, except for a few cases where leaf-blades of too many culms were removed. [the rest omitted]

[学科分类] 农业科学（综合）