On the Artificial Germination of Pollen of Rice Plants : VIII The Relation between Temperature and Protoplasmic Streaming (II)

Abstract

In order to know how different temperature affect the protoplasmatic streaming in pollen tube of rice plants, the rate of protoplasmic streaming (μ/sec.) was mesured under microscope from 5 minutes after setting of pollen on the germination media. 1) Changes of the streaming rate were examined with time under 20°, 30°and 38°C temperature conditions by using 7 Japanese varieties. Results are shown in Figure 1. At 30°C the initial rate of streaming was very high, but it was then slowed down. Under 20°C condition the rate was always low during the whole period of the experiment. However, when the temperature rose to 38°C, it was found that the initial rate of streaming showed the intermediate values between those of 30°C and 20°C, but it became low as the time went on. In all experiments, no varietal differences were found in the streaming rate without some exception. 2) Experiments were carried out to investigate the effect of changes in temperature (30°⇄20°C) on the rate of protoplasmic streaming. The germination beds were transfered from 30°to 20°or fro, 20°to 30°C 10 minutes after pollen setting. In the check plots it was mesured without giving temperature change. The results are given in Figure 2. According to those in the 30°→20°C plot, the rate of streaming became slow 1∼2 minutes after changing of temperature. The rate lay between those of both 20°C and 30°C check plots 4∼10 minutes after changing. In 20°→30°C plot, the streaming rate became very high immediately after changing. But the rate was lowered with time, being followed by somewhat lower rate than 20°C check plot found 8∼10 minutes after changing. These results suggest that the protoplasmic streaming is very sensitive to change of temperature.