Excessive use of fertilisers can lead to wilting of plants due to exosmosis.

Explanation:
Exosmosis is the process of water moving out of the cell due to the higher concentration of solutes in the cell. When excessive fertilisers are used, they increase the concentration of solutes in the soil. As a result, the plant roots absorb more water from the soil, leading to an increase in the concentration of solutes in the plant cells. This causes water to move out of the cells, resulting in wilting of the plant.

Effects of excessive use of fertilisers on plants:

1. Nutrient imbalances: Excessive use of fertilisers can lead to an imbalance of nutrients in the soil, which can cause nutrient deficiencies or toxicities in plants.

2. Soil acidity: Fertilisers can increase the acidity of the soil, which can affect the growth of plants.

3. Decreased soil fertility: Overuse of fertilisers can lead to a decrease in soil fertility over time.

4. Environmental pollution: Excess fertilisers can run off into waterways and cause pollution, leading to harmful algal blooms and other environmental problems.

5. Reduced biodiversity: Overuse of fertilisers can affect soil organisms, leading to a reduction in biodiversity.

Conclusion:
Therefore, it is important to use fertilisers judiciously and to follow recommended application rates to avoid negative impacts on plant growth, soil fertility, and the environment.