Why a tomato plant is likely to wilt if too much fertilizer is applied to it

Once two solutions of different concentrations come into contact, water molecules will flow from low to higher concentrated solution. Hence application of fertilizer makes the soil solution of higher concentration so water flow out of the plant by osmosis. The tomato plant plasmolyses/loses water and wilt.

Note

Plasmolysis describes a process involving a plant cell losing water content and therefore contracting and shrinking its cytoplasm and plasma membrane away from the inside of its cell wall. This occurs if the solution surrounding a plant cell is hypertonic or has a high concentration of solutes like salt.

Diffusion is the process whereby molecules/particles of a liquid/gas move from a region of higher concentration to a region of a lower concentration until they are uniformly spread throughout an occupied space.

Osmosis is the movement of water molecules from a region of lower concentration to a region of higher concentration through a semi-permeable membrane

OR

Osmosis is the movement of water molecules from a dilute solution to a concentrated solution through a semi-permeable membrane.

Differences between osmosis and diffusion