How would filamentous green algae look like in a hypertonic solution?

Answer 1

A good question. Let's think about this:

1. Filamentous green algae is small, but it is a plant. Plants have cell walls, not just cell membranes.
2. A hypertonic solution means that there is more salt in solution than in the plant cells.
3. Because the solution is more concentrated outside the plant cells, we expect the water to move out of the cells and into the hypertonic solution.

So far so good. One thing to remember, because the algae has cell walls the algae will not look like it has changed much (no shrinking or ballooning). What WILL show change is the actual cell inside the cell wall envelope.

So in an isotonic solution, we expect to see green algae cells where the cell fills the entire cell wall envelope. A green rectangle inside a clear rectangle with very little space between them (no gaps).

And in a hypertonic solution we expect to see the cell shrink inside the cell wall envelope; shrinking more and more as the concentration outside increases and more water is lost from inside the cell, until it ends up looking like a green pea inside a clear box.