Suzanne O. answered • 10/25/19
International Experience and Multiple State Certifications
Yes, plant cells can expand or shrink, but they do have limits.
Plants have both a cell membrane and a cell wall.
The cell membrane is just like that of animals, it is flexible and can shrink and swell from osmosis.
But the cell wall is not flexible. It forms a box around the cell to provide structure, and it will not shrink or expand from osmosis.
A filamentous green algae cell in an isotonic solution looks like a green rectangle inside of a clear box, almost no gap between the two.
The same filamentous green algae cell in a hypertonic solution looks like a clear box with a green pea inside of it.
And if you were to put the same filamentous green algae cell in an extreme hyoptonic solution (like pure distilled water), you might expect to see the cell wall crack from the pressure and the green goo start to ooze out.
Generally speaking, the cell wall is the limit.
