Influence of tissue source and growth rates on dry weight and carrageenan composition of Chondrus crispus (Gigartinales,Rhodophyta)

Carrageenan analyses were conducted on vegetative female clones of Chondrus crispus that were cultured to provide tissues with differing growth rates. Tissue dry weights increased from apex to base of fronds. Total carrageenan contents were lower in apical 1 to 2 cm segments than elsewhere in the frond, except when the alga was grown at high photon irradiances. Clone 373A contained more carrageenan than clone G8. The proportion of 0.3 M KCl-soluble polymers in the total native carrageenans varied from 44 to 92%, being highest in older tissues of fronds cultured at high photon irradiances. The apical 1 cm segments contained less KCl-soluble carrageenans than other tissues from the corresponding fronds. The KCl-soluble carrageenans, when alkali-modified and refractionated, afforded the expected kappa-iota carrageenan in > 79% yields. The remainder consisted of a polymer containing 23.1% SO₃Na and 8.4% 3,6-anhydrogalactose. Lambda carrageenan was not detected. Variations in carrageenan distribution between the apical region and other parts of the frond may reflect the increasing influence of medullary tissue developed as the immature cells differentiate.