EFFECT OF MOISTURE STRESS AND LEAF AGE ON BENTAZON ABSORPTION IN COMMON COCKLEBUR (XANTHIUM-STRUMARIUM) AND VELVETLEAF (ABUTILON-THEOPHRASTI)

More than 70% of all C-14-bentazon absorption occurred within 4 h after herbicide application regardless of adjuvant, Moisture stress reduced C-14-bentazon absorption by common cocklebur and velvetleaf, Mature (second true leaf) and moisture-stressed leaves of velvetleaf had 50 and 17 mu g cm(-1) more epicuticular wax (ECW) than did juvenile and unstressed leaves, respectively, Common cocklebur had less C-14 in the ECW and lower total C-14 in treated mature leaves compared to juvenile leaves, The use of 28% urea ammonium nitrate (UAN) or crop oil concentrate (COG) increased C-14 in ECW samples of both plant species, regardless of leaf age or moisture stress, More C-14 in the ECW did not always correlate with more C-14 in the leaf tissue, Adjuvants increased C-14-bentazon absorption into leaves of plants that had been stressed.