Fig. 1. The molecular weight distribution of un-irradiated and irradiated carrageenan.
The profile has fraction eluting at higher retention time in comparison
to un-irradiated sample indicating formation of lower molecular weight fragments
in the 250 kGy irradiated sample. This fraction also contained less than 20,000
molecular weight oligomers of carrageenan which are responsible for plant growth
promotion in this study. The molecular weight of the un-irradiated commercial
k-carrageenan was estimated to be about 100,000.