Amyloplastenentwicklung und Stärkesynthese in Samen von Futter- und Markerbsen

Development of amyloplasts and starch synthesis in seeds of field and garden peas Amyloplast development and changes in starch and amylose content in seeds of field and garden peas (Pisum sativum ssp. sativum and ssp. medullare) was studied from flowering to maturity in view of a possible relationship between amyloplast form and starch composition. Starch and amylose contents increased at different rates in both subspecies. In field peas starch content had reached the maximum (44 % in DM) 26 days after flowering with 45 % amylose in total starch. In garden peas, 25 days after flowering, starch content had only reached half of its maximum (32 % in DM) with an extremely high amylose proportion (88 %). At that growth stage form and size of amyloplasts were similar in both subspecies. There seems to be no tight relationship between form of amyloplasts and proportion of amylose in total starch. But then, when amyloplasts abruptly increased in size those of garden peas disrupted suddenly. This disruption is not due to a high amylose content. Because in a cross-breeding of field and garden peas, which was also investigated, the amyloplasts had remained intact irrespective of a high amylose proportion (63 %). The disruption may be due to differences in arrangement of starch molecule and in structure of plastid envelope.