A plant placed in a hypotonic solution would most likely become firmer and more rigid.

Key idea: turgor pressure

  • Plant cells become firm (turgid) when water moves into them by osmosis.
  • This happens when the surrounding solution has a lower solute concentration (more dilute) than the cell interior, i.e., a hypotonic solution.
  • Water enters the cell, fills the central vacuole, and presses the membrane against the cell wall, increasing turgor pressure and making the plant stand upright and rigid.

Why not the other options?

  • Hypertonic : Water leaves the cells, they shrink (plasmolysis), and the plant wilts rather than becoming firm.
  • Isotonic : Water movement in and out is balanced, so there is no net gain of water and no increase in rigidity.
  • “Osmotic” (as a label) is vague; all of these situations involve osmosis, so it does not specifically describe the condition that makes the plant firmer.

So, among the choices hypertonic, hypotonic, isotonic, osmotic , the correct answer is hypotonic.