Biosynthetic incorporation of the aminobutyl group of spermidine into pyrrolizidine alkaloids

alcaloides alkaloids asteraceae botanica botanique botany compositae espermidina malezas mauvaise herbe metabolism metabolisme metabolismo plant growth substances plante toxique poisonous plants poliaminas polyamine polyamines putrescina putrescine pyrrolizidine alkaloids senecio senecio vulgaris spermidine sustancias de crecimiento vegetal weeds