Potassium

Unlike nitrogen and phosphorus, potassium has no structural functions, but it is the most common cation in the main metabolic processes of plants.

On the one hand, potassium regulates the opening and closing of stomata, facilitating the plant's exchange of water and gas with the atmosphere. This mechanism is associated with a variation in the concentration of K+ in the guard cell vacuole. In this way, K+ gives the plant greater tolerance to water stress and salinity.

On the other hand, potassium activates enzymes involved in key metabolic processes such as protein synthesis, photosynthesis, and the transport of sugars throughout the plant. Additionally, potassium is involved in fruit ripening and in the synthesis of pigments such as lycopene, which is responsible for the red color of tomatoes.

ABSORPTION

It is absorbed by the plant in the form of K+ ion, mainly via the roots.
It is the most abundant cation in plants, as it can represent up to 10% of their dry weight.