in callus grown on high ( 11.5 micromolar ) alpha-naphthalene acetic acid , suboptimal for alkaloid biosynthesis , putrescine and spermidine conjugates were the main putrescine derivatives , while in callus grown on low ( 1.5 micromolar ) alpha-naphthalene acetic acid , optimal for alkaloid formation , nornicotine and nicotine were the main putrescine derivatives .
C0037871
conjugates
C0034170
putrescine