Potassium deficiency reduces photosynthesis. Potassium can obviously increase the absorption and utilization of nitrogen by plants, and quickly transform them into proteins. Potassium can also promote the economic use of water in plants. As potassium ions accumulate more in crop cells, the cell osmotic pressure increases and causes water to move from a low concentration of soil solution to a high concentration of root cells. When the supply of potassium is sufficient, crops can effectively use water and keep it in the body, reducing the transpiration of water.
Another characteristic of potassium is to help crop resistance. One of the important physiological functions of potassium is to enhance the regulatory effect of cells on environmental conditions. Potassium can enhance plant's tolerance to various adverse conditions, such as drought, low temperature, salt content, disease and insect pest, lodging and so on.
The most common symptom of potassium deficiency in plants is burning along the leaf edge. First, it starts from the lower leaves and gradually expands to the upper leaves. The growth of potassium deficient plants is slow and the root development is poor. The stems are fragile and often fall in lodging. Seeds and fruits are small and dry. Plant resistance to disease is low.