Carrageenan patterns in the Gigartinaceae

Carrageenans of known reproductive phases of gigartinacean species are shown to differ: gelling κ (τ)-type carrageenan occurs in all instances in gametophytes, and viscous non-gelling λ-carrageenan or its variant ξ- or π-carrageenan in tetrasporophytes. Multiple analyses demonstrate that the carrageenan type is a species characteristic, with little difference between individual samples. No difference exists between the carrageenans of male and female plants of each species. Carrageenan chemistry combined with morphological, reproductive and life history feature is useful for defining the taxonomic limits of this family and these genera.