methods with higher survival rates or improvements in protoplast culturing methods. Examinations of protein growth using protoplasts from sea lettuce, kelp, and
laver have found very few proteins to exist in the cell wall.
Protoplasts are also used for research on the biosynthesis and structure of seaweed polysaccharides and the production of aromatic constituents. Issues that will
have to be addressed in future tissue culturing include identification and isolation of
seaweed growth and differentiation factors, a more precise understanding of the cell
wall’s components and structure, and development of standardization techniques
for cell wall zymolysis (Amano 1990).
6.5 Cell Fusion
Cell fusion is a very useful technique for improving strains of seaweeds that are
difficult or impossible to cross-breed. Methods used for protoplast cell fusion in
higher plants include the sodium nitrate (NaNO 3 ), high pH-high calcium, polyethylene glycol (PEG), dextran, electricpulse, and centrifugal force approaches;
Fig. 6.7 Cell fusion through Polyethylene Glycol (PEG Method)
6.4 Protoplast Production in Seaweed Cells
161