Alkaloid Distribution in Seeds of Argemone mexicana L. (Papaveraceae)

Abstract. Seeds of Argemone mexicana L. accumulate significative amounts of sanguinarine. The analysis of the distribution of this alkaloid through the tissues of mature seeds revealed that up to 60 % of its contents was found tightly fixed to the different components of the seed external covers where it persisted during seedling germination. Contrastingly, sanguinarine contents in cotyledon accounted for the remaining 40 % and it could have been, at least partially, mobilized to the newly formed hypocotyls during emergence from seeds. Berberine was only detected in immature seeds and in seedlings once cotyledons were totally displayed. These results are discussed as a possible sanguinarine role in the chemical protection during seedlings germination.   Resumen. Semillas de Argemone mexicana L. acumulan cantidades elevadas de sanguinarina. Un analisis de la distribucion de alcaloides en los diferentes tejidos que componen la semilla revelo que hasta un 60 % del contenido se encontraba fuertemente unido en las capas que forman la cubierta exterior, donde se retuvieron durante la emergencia del hipocotilo. En contraste, los cotiledones presentaron el 40 % restante y parte de ello pudo haber sido movilizado al hipocotilo al emerger. Berberina solo se observo en semillas inmaduras y en plantulas en desarrollo con los cotiledones desplegados. Estos resultados se discuten en funcion del posible papel defensivo de la sanguinarina durante la germinacion.