UPTAKE AND TRANSLOCATION OF EXOGENOUSLY APPLIED 7-OXYSTEROLS IN BARLEY

7 beta-Hydroxy- and 7-oxocholesterol as well as [3 alpha,7 alpha-2K,H- 2(2)]-7 beta-hydroxysitosterol and [3 alpha-H-2]-7-oxositosterol were sprayed on the primary leaves of 7;day-old barley plants. A higher upt ake of the 7-oxosterols compared to the 7 beta-hydroxysterols and a hi gher uptake bf the cholesterol compared to the sitosterol derivatives was observed. The results also indicated that the uptake of [3 alpha,7 alpha-H-2(2)]-7 beta-hydroxysitosterol was dependent on the concentra tion whereas the uptake of [3 alpha-H-2]-7-oxositosterol was rather in dependent of the concentration on the leaf surface. No significant dif ferences of the concentrations of [3 alpha,7 alpha-H-2(2)]-7 beta-hydr oxysitosterol and [3 alpha-H-2]-7-oxositosterol were detected in the l eaves when the plants were harvested 3 days or 4 weeks after the treat ment. The sprayed 7-oxysterols were never detected in the roots. [3 al pha,7 alpha-H-2(2)]-7 beta-hydroxysitosterol and [3 alpha-H-2]-7-oxosi tosterol were also applied to the roots of 11-day-old plants. The data indicated the higher uptake of [3 alpha-H-2]-7-oxositosterol compared to [3 alpha,7 alpha-H-2(2)]-7 beta-hydroxysitosterol and the transpor t of both into the leaves. (C) 1998 Elsevier Science Ltd. All rights r eserved.