Studies on the Assimilation and Translocation of 14CO2 in Ladino Clover : VII. Effect of temperature, especially low temperature on the translocation of 14C-assimilates

摘要

The effect of temperature, especially low temperature on the translocation of 14C-assimilates was examined. 1) At the favorable temperature for growth (15°-25°C), the 14C-assimilates of ladino clover moved at the speed of about 30 cm/hr. At 10°C, speed was reduced and the speed of 14C-assimilates was about 20 cm/hr. 2) The basipetal translocation of the 14C-assimilates was faster and more dominent than the acropetal when 14C was fed leaf No. 4 from growing points. The gradient of 14C-assimilates to the basal part of plant (i.e. basipetal) was more clear and sharp than those of acropetal. 3) Total amount of translocated 14C-assimilates was greater in the high temperature than the low temperature in the range of 10°-25°C. 4) When plants grown at 20°C were transfered to low temperature, speed of translocation was reduced, particularly below 10°C. At 0°-2°C, and 5°C translocation was almost completely ceased. But plants grown at low temperature, 5°C, showed the adaptation to the condition of low temperature, and the inhibition of the low temperature on the translocation was reduced. At any rate, the low temperature reduced the speed of translocation of 14C-assimilates. It seemed that this will be one of the reason for delayed growth at low temperature, especially in the case when the plants were exposed to the low temperature suddenly.