THE EFFECT OF TEMPERATURE UPON TRANSLOCATION OF CARBOHYDRATES IN THE TOMATO PLANT

Abstract

Tomato plants with healthy root systems will bleed for a considerable time after decapitation. The rate of bleeding depends upon the activity of the root system, and this in turn is affected by its sugar content. By recording the rate of bleeding any changes due to sugar applied to the leaves could be measured. It was found that when 7% sucrose was applied to 2 leaves, inserted about 25 cm. high on the stem, the rate of bleeding suddenly increased about 11.5 hrs. after immersion of the leaves in sugar. By varying the temp. along a 20 cm. length of stem the effect of temp. on the rate and intensity of sugar translocation could be measured in terms of bleeding. The time necessary for the sugar to take effect decreased from 11.5 at 25[degree]C to 8 hrs. at 1[degree]C, whereas the amt. decreased from 7.5 drops to 2 drops as the temp. increased. This is interpreted to mean that in the tomato plant both the rate and intensity of sugar transport have a QJ0 well below 1.