Abstract
The soluble leucine pool in maize root tips may be divided for simplicity into 2 pools a metabolic pool and a storage pool. Leucine supplied by the transport system or by endogenous synthesis enters the metabolic pool. After the removal of the transport system, both pools are reduced in size; however, the metabolic pool is most severely affected. Therefore the transport system is considered to be responsible for maintaining the level of leucine in the metabolic pool.