Osmosis

Excess fertilizers result in osmotic withdrawal of water from cells, as they form a hypertonic solution outside the cells. Shrinkage of the protoplast of a cell from its cell wall under the influence of a hypertonic solution is called plasmolysis. Hypertonic solution causes exosmosis or withdrawal of water from cytoplasm and then the central vacuole of cell to outside and hence result in wilting of the plant.