The Effect of Hypocotyl Temperature on Translocation of Carbohydrates from Bean Leaves

Abstract

The effect of hypocotyl temp., within the range of 7-40[degree]C, on the transport of carbohydrates from bean leaves was investigated. The indirect approach of measuring translocation in terms of stem elongation was used. By means of temp. jackets only the temp. of the hypocotyl was varied, the temp. of the rest of the plant being maintained at 25 [plus or minus] 1[degree]C. In some of the expts. growth occurred while the plants were exposed to artificial illumination of approx. 1000 foot candles. In other expts. growth occurred in complete darkness, sucrose being supplied by immersion of the blade of one of the primary leaves in a 0.75 [image] sucrose soln. Max.transport of both naturally occurring and artificially supplied carbohydrate, as measured by stem elongation, occurred at a temp. of approx. 33[degree]C. The temp. differentials,although applied outside the direct path of translocation of carbohydrates from the primary leaves to the stem, affected stem elongation in a manner similar to petiole temp.