TIME-COURSE STUDY ON THE MOBILITY AND PATTERN OF DISTRIBUTION OF FOLIAR-APPLIED BORON IN PEACHES

One-year-old 'Red Haven' peach (Prunus Persica) trees grown in pots in the greenhouse were used to study the time course mobility and patter n of distribution of boron (B). Enriched-B-10 boric acid solution was evenly spread onto the abaxial side of the fifth leaf (numbered acrope tally). After harvesting at different time intervals, selected plant p arts were analyzed for B-10 using an ICP-MASS spectrometer. The result s showed that within 4 hours, B could be taken up and translocated bid irectionally to all plant parts, except for the fine roots. Treated le af, green stem, and fine root were the tissues having high B-10 concen trations in comparison to the other tissues. The highest B-10 concentr ations in the fed leaf, green stem, and fine root were reached in 12 h ours, at the 4th week, and in 72 hours, respectively. The total B-10 a bsorbed averaged 0.3% of the total B-10 applied, with the highest tota l percent recovery of 0.43%, which was reached in 72 hours. The total amount of B-10 exported from the fed leaf was more than 50% of the B-1 0 absorbed. A comparison of the B-10/B-11 ratio and the B-10 content w as used as the parameter of B movement. The method of data expression is also discussed.