PERMEABILITY OF PEACH LEAF CUTICLES TO BORON

Isolated leaf cuticles and intact plants of one-year-old potted 'Red H aven' trees grown in the greenhouse were used to study the permeabilit y of leaf cuticles to boron (B). The isolated leaf cuticles were prepa red enzymatically. Flux was determined using a transport cell. Permeab ility coefficient (P) was calculated and used as the parameter of cuti cle permeability to B. For intact plant studies, enriched-B-10 boric a cid solution was evenly spread onto the abaxial or the adaxial side of a leaf. The trees were sacrificed three days after the treatment and selected plant parts were analyzed with ICP-AES and ICP-MS spectromete rs. The log content was used as the parameter of B permeability in viv o. The permeability coefficient of peach leaf adaxial cuticle was in t he order of 10(-7) cm/sec. There were no difference in the permeabilit y coefficients among B concentration and surfactant treatments. The pH had variable effect on B absorption through the cuticle of the adaxia l side of the leaf. For the in vivo study of B uptake by peach leaves, the abaxial side was more efficient than the adaxial side, with the t otal B-10 taken up four times greater in the abaxial side than the ada xial side. The absorption percentages of the total B-10 applied in the abaxial and adaxial sides were 0.31% and 0.08%, respectively. Scratch es on the treated leaves made the total B-10 uptake and translocation higher than the control treatment.