Does osmosis flow in or out of a plant?

In a general sense, osmosis flows into a plant. Provided that osmosis is the diffusion of water molecules that pass through a semipermeable membrane to equalize the overall concentration, there are a few conditions where the plant cells will respond to different forms of solutions; as evident by the cell's ability to gain or lose water.

Hypotonic Solution:

(hypo-, below)

While an animal cell would lyse, or burst, this is the ideal solution for a plant cell. For the reason that the solute concentration in the solution is lower than the cell's solute concentration, where the net flow of water enters the cell.

Isotonic Solution:

(iso-, same)

In an isotonic solution, the cell's volume remains constant. The net flow of water is facilitated, where the rate of water that enters and exits the cell is equal; meaning that the solute concentration of the cell, and the solution is also the same.

Hypertonic Solution:

(hyper-, above)

In contrast to a hypotonic solution, the solution has a higher concentration of solutes, and water exits the cell; a cell may possibly die from dehydration, or plasmolysis, a process where the cell shrivels from the excessive loss of water.

To conclude, osmosis is a process that directs the flow of water into regular plant cells, in the same way that a cell placed in a hypotonic solution would inflate, since the water molecules move toward the side of a selectively permeable membrane with a higher solute concentration. Even more, hypotonic, isotonic, and hypertonic solutions are terms used to describe tonicity, cells in relation to their environment that includes the application of osmosis.