INHIBITION OF THE PRODUCTION OF PHENOLIC-COMPOUNDS IN BRASSICA-NAPUS 2-AMINO-OXYACETIC ACID

Phenolic compounds precipitated with caffeine were more widely distrib uted in the cytoplasm and nucleus in the outermost layer of the colume lla of germinating Brassica napus root than in the other layers. Amino -oxyacetic acid, an inhibitor of the biosynthesis of the C6C3 part of phenolic compounds, inhibited the biosynthesis of phenolics, and made dark deposits less numerous in all three of the outermost layers of th e columella. The first layer was the most responsive, because symptoms of inhibition were already visible after 3 h. After 24 h the inhibiti on in the second and third layers was proportional to the concentratio n. The first layer contained less deposits than the control, but more than the second and third layers, suggesting that many of these compou nds in the first layer were present at the outset.