Yellowish edges in leaves due to potassium deficiency
Potassium deficiency in plants can lead to various symptoms, one of which is the appearance of yellowish edges in leaves. This occurs due to the role of potassium in regulating the opening and closing of stomata, which are tiny pores on the surface of leaves that control gas exchange.

Explanation:
- Potassium is essential for the activation of enzymes involved in photosynthesis and respiration.
- It helps in the transport of sugars and other nutrients within the plant.
- Potassium also plays a crucial role in maintaining turgor pressure in plant cells, which affects overall plant growth and development.

Effects of potassium deficiency:
- Yellowing of leaf edges is a common symptom of potassium deficiency, known as chlorosis.
- In severe cases, the yellowing can progress to necrosis, where the tissue dies off.
- Other symptoms may include stunted growth, weak stems, and poor fruit development.

Preventing potassium deficiency:
- Regularly test the soil to ensure it has sufficient potassium levels.
- Fertilize the plants with potassium-rich fertilizers as needed.
- Maintain proper watering and drainage to ensure optimal nutrient uptake by the plant.
In conclusion, yellowish edges in leaves are a clear indicator of potassium deficiency in plants. By understanding the importance of potassium and its role in plant growth, proper measures can be taken to rectify deficiencies and promote healthy plant development.