Thanks Lee

A different take . . . .

Land plants have water-insoluble fibrillar cellulose plus water-soluble "matrix" hemicelluloses, pectins, etc.

Marine macroalgae aka seaweeds also have fibrillar polysaccharides but not necessarily cellulose [some have xylans], probably at lower concentrations than land plants.

There is a large variation in regards to the water soluble [matrix] polysaccharides in seaweeds, agar, carrageenans, carragars, alginates, fucoidan, ascophyllan, sulphated xylans, etc etc.

You also have differences in storage polysaccharides. i .e brown seaweeds do not store starch, they store laminaran.

Thanks David

One of the only major deducible similarities between algae and plants are that they can both photosynthesize. Also, algae is a large category of species; if you used the model species, it was probably the microalgae Chlamydomonas r. The biggest difference with this species and plants is that the species is unicellular, and plants have multiple and diverse types of cells. I guess another shared characteristic is that they are both categories of Eukaryotic organisms.

Not only are the cell walls likely different between an algae cell and a plant cell, but the extracellular matrix and its components are probably different. This is probably because the cell types have different products and also because they are found in different types of environments. They also interact with their environments differently.

The bioherbicide maybe wasn't ingested so readily by the algae cells, since they are typically submerged in water and likely do not drink it as much as plants, which actively seek out water to drink. Plant cells are typically bigger too and would drink more water.

Thanks Tristan