The Respiration in the Seedling Roots of Rice, Wheat and Barley as innuenced by Temperature

1.In order to investigate the relationship between respiration and physiological characters of roots, the respiratory rate （Qo_2) of the excised seedling roots （1～3cm. Segments）of rice, wheat and barley was measured in various temperature levels from 10 to 45℃. With W_<ARBURG>'s method . 2.There were two peaks in each temperature curve for respiration.These peaks were 33～35 and 39～40℃.for rice, 33 and 35℃. For wheat, and 31～32 and 35℃.for barley. The temperature for first peak in each plant resembled the temperature for maximum rate of protoplasmic streaming in root hair as reported by one of the authors. 3.The rate of respiration increased in an exponential curve under the first peak in each plant. Between 10 and 30℃.,Q_<10> values were 2. in rice plant which had grown at 20～25℃.,2.8 in rice plant which had grown at 30℃.,and 2.0 in wheat and barley plants which had grown at 20～25℃. 4.The respiratory rate decreased with increasing distance from the root apex. As to the relation between temperature and respiration,however,the remarkable difference was not observed in the different root reglons.