Studies on phloem exudation from Yucca flaccida Haw. XII. Rate of flow of 14C-sucrose from a leaf to the wounded inflorescence top. Evidence for a primary origin of the major part of the exudate sucrose

In a quantitative tracer study, evidence has been obtained that the photosynthetic products of mature Yucca leaves enter a pool of mobile carbohydrates that supplies the major part of the sucrose present in the exudate from the wounded inflorescence top. In the described experiment the activity in the pool has a half-value time of about 3.2 days. The pool is probably identical with the soluble carbohydrate fraction of the leaves.