Effects of Soil Temperature upon the Development of Tillering Buds formed on the Lower Nodes of Paddy Rice

The experiments were carried out in order to establish the effect of soil temperature upon the development of tillering buds in paddy rice plants transplanted. For 15 days extending from May 19, (the 3rd day after transplanting) to June 3, the soil temperature was maintained at 28°C in H plots and at 20°C in L plots by the aid of constant temperature water tanks. In addition, an observation was made on the effect of lamina-cutting upon the development of tillering buds. The results are as follows. (1). The tillering buds already differentiated on the lower nodes, such as the 2nd and 3rd ones, grew well in L plots, while in H plot those were scarcely developed and those on the higher nodes, such as the 4th and 5th ones, began to grow. (2). Lamina-cutting had an harmful effect on the development ot tillering buds, especially of those which were vigorously growing in length. (3). So far as the histological observations on tillering buds formed on the lower nodes are concerned, it may be safely said that cell divisions in the shoot apex and its surrounding tissues are inactive in H plots and are active in L plots