Endoreduplication occurs during pod wall development in temperate grain legumes

Differentiation to a specialized function in plant tissue is associated with an increase in the DNA content of the cells over the diploid state. Using flow cytometry, ploidy levels were assessed during pod development in three white lupin genotypes under three environmental conditions and in other lupin species and temperate grain legumes in one environmental condition. Endoreduplication was found in the pod walls of all genotypes studied. Higher ploidy levels coincided with maximal growth of the pod. DNA replication was not related to the proportion of the pod that comprised walls. Endoreduplication also occurred in other temperate grain legumes with at least two DNA duplications during the development of the pod walls. The biological significance of endoreduplication in the pod walls of grain legumes is unknown, but could be related to the storage function of these organs. (C) 2000 Annals of Botany Company.