Concomitant Photosynthesis Implicated in the Light Effect on Translocation in Bean Plants

Abstract

Light supplied during a 3-hr translocation period stimulated [14C]sucrose translocation in bean plants, both when the plants had spent the previous 30 hr in the light and when they had spent this period in the dark. Light during the trans-location period was also very effective when the latter was shortened to 30 min and followed a 30-hr pretreatment period in the light. It is thus unlikely that the light effect is due to a change in overall leaf sugar level, since the latter will not have altered markedly during the final 30 min of a light period of more than 30 hr. Not only was more 14C translocated out of the leaves in the light, but a far higher percentage of the 14C so translocated reached the roots.