Abstract
In the previous three papers, we have obtained the methods of growth analysis about the tillering behavior of a rice plant. Using the methods, the temperature effects were investigated in the present paper. Plants (cv. Sasanishiki, 1 plant/pot) were grown in different temperature conditions as 30 (6:00-18:00)-25 (18:00-6:00)°C (plot H), 24-19°C (plot M), 17-12°C (plot L), respectively, after 5.8 plant age expressed by leaf number (the number of spread leaves plus the ratio of the length of the emerged part of the blade of emerging leaf on the main stem). The rate of increase in tiller number against time was H>M>L plot, but the rate against the plant age was L>M>11 plot. It was possible to analyze the tillering behavior into two factors: one is the differences (D) in growth speed between the main stem and each tiller, and the other is the tillering pattern at the synchronous growth (the leaf on each tiller and that on the main stem expanded synchronously in a plant). D of the second-order tillers was L>M>H plot, and D of the third-order tillers was M>H plot. Tillering curves of the three plots at synchronous growth was corresponded with each other. Therefore the temperature influenced the balance of' growing speed between tillers and main stem, and had no effect on the position of tiller emergence.
