MOBILITY OF FOLIAR-APPLIED BORON IN ONE-YEAR-OLD PEACHES AS AFFECTED BY ENVIRONMENTAL-FACTORS

One-year-old potted 'Red Haven' peach (Prunus persica L. Batsch) trees grown in the greenhouse were used to study the mobility of boron (B). Enriched-B-10-boric acid solution was evenly spread onto the abaxial side of a leaf. After harvesting at different time intervals, selected plant parts were analyzed by ICP-AES and ICP-MS spectrometry. The B-1 0 content was used as the parameter of B mobility. The results showed that among the six B concentrations (0, 150, 300, 600, 900, and 1,200 ppm) studied, the 1,200 ppm treatment had the highest B-10 content in every plant tissue. There was little difference between the middle and bottom treatments in the leaf position-treated experiment. However, i f leaf area was not considered, the terminal leaf was less efficient i n taking up B-10 than the other two positions in the same experiment. Plastic coverage on the treated leaf helped the uptake of the treated B-10-boric acid. High relative humidity (100% RH) treated plants had h igher B-10 content than the low RH-treated (50%) plants. About 0.2 to 0.3% of the total B-10 applied was absorbed by the peach trees.