Abstract
We observed the efffects of kinetin absorbed from roots on the growth of main stem and tillers in rice plants grown in solution culture. The growth of the plants in plant length, plant age expressed by the number of leaves, length of leaves, number of roots and length of roots were inhibited, with a few exceptions, by kinetin irrespectively of light intensity and nitrogen concentration in the culture solution. The effects on the development of tillers were dependent on the light intensity. Kinetin inhibited the increase in number of tillers of the plant, the age of tillers expressed by the number of leaves and length of tillers with a few exceptions under natural light intensity. Under low light intensity, on the other hand, kinetin promoted the increase in number of tillers of the plant and the development of tillers in number of leaves and length. The development of the tillers at lower nodes such as the 2nd and 3rd nodes, whose development seemed to have stopped at the time when kinetin was absorbed, were promoted by kinetin. No relationship was observed between the nodal position of the roots supplied with kinetin and the nodal position of the tiller affected by kinetin.
