METABOLISM OF 4-NITROPHENOL IN ASEPTICALLY CULTIVATED PLANTS OF THE SPECIES WHEAT (TRITICUM-AESTIVUM L.), SOYBEAN (GLYCINE-MAX L.), WILD OAT (AVENA-FATUA L.) AND CORN COCKLE (AGROSTEMMA-GITHAGO L.)

The metabolism and behaviour of the root applied xenobiotic [U-C-14] 4 -nitrophenol was studied in intact, aseptically grown plants of wheat ( Triticum aestivum L.), soybean (Glycine max L.), wild oat (Avena fat ua L.), and corn cockle (Agrostemma githago L.). After 7 days of expos ition, different port-ions of the applied radioactivity were found abs orbed into the plants: wild oat, 11.4%; corn cockle, 16.9%; wheat, 18. 2%; soybean, 47.8%. Complementary long-term experiments performed only with wild oat and corn cockle showed chat the uptake continued, and a fter 28 days of exposition, C-14 portions found in the plants were 24. 7% and 19.9%, respectively. In all species studied, the main percentag es of absorbed radioactivity were confined to che roots (>75% after 7 days of incubation). After 28 days, however, considerable portions of C-14 were translocated to the aerial parts of wild oat (43.6% of absor bed C-14) and corn cockle (57.9%). 4-Nitrophenol was almost quantitati vely transformed by all plant species examined to polar soluble conjug ates, besides minor amounts of non-extractable residues (wild oat: 13. 2% after 1 day, corn cockle: 2.0% after 28 days). The primary conjugat e was 4-nitrophenyl-beta-D-glucoside, which was identified by TLC and HPLC. In the two monocotyledonous species, this product was partially further conjugated to 4-nitrophenyl-beta-D-gentiobioside, and an unide ntified 4-nitrophenyl-(1 --> 4)-diglucoside. Additionally the 6'-O-mal onylated beta-glucoside was formed in wheat. In both dicotyledonous sp ecies, the beta-glucoside was in part found to be 6'-O-esterified with malonic acid.