WATER-SOLUBLE POTASSIUM (WS-K)

Potassium deficiency occurs when the soil lacks potassium. Even though enough potassium exists, if the soil contains a lot of lime and magnesium, the plant suffers from potassium deficiency, because the absorption of potassium is suppressed due to those trace elements. Potassium deficiency can also easily occur in sandy soil which has less humus.

FUNCTIONS OF WATER-SOLUBLE POTASSIUM (WS-K):

1. Potassium activates the starch-synthesizing enzyme, facilitates the translocation of photosynthate, and helps to relocate the storage substances in a starchy crop.

2. Potassium deficiency symptoms occur first on older leaves, because potassium is a highly mobile element in the plant. The potassium content in the leaf decreases rapidly in the fruit enlargement period because a lot of potassium is translocated to the fruit.

3. The principal function of potassium is to grow meristematic tissues.

4. Potassium regulates the plant stomata and water use. At low concentrations, potassium decreases the growth rate, the size of the fruit, and the moisture content in the tissues. Therefore, potassium plays a vital role in cell enlargement. When the stomata are opened, the potassium content in guard cells is high; when the stomata are closed, the potassium content in guard cells low. In the light. Guard cells produce ATP through photosynthesis and absorb potassium by using energy from ATP. Consequently, when potassium is accumulated in the guard cells, the turgor pressure rises resulting in the opening of the stomata.

5. Potassium promotes synthesis of the carbon dioxide fixing enzyme, decreases the diffusive resistance of CO2 in the leaf, and activates various enzyme reaction systems.

6. The absorption of potassium is metabolic and its rate is high and increases the fluidity in the system. The main route of translocation is bound for meristematic tissues. Sometimes, potassium is translocated again from old tissues to young tissues.

7. Potassium functions to regulate the absorption of moisture, to enhance the translocation of photosynthates and to activate metabolic enzymes.

8. Potassium is abundant in leaves, the stems and the root tips as almost a form of salt. Potassium is very mobile in the plant, because it always exists as an ion or an easily ionizable form.

9. Potassium functions to help transport carbohydrates, to vitalize carbon assimilation, to control the turgidity (swollen) of protoplasm and to improve resistance to drought and freezing of plant tissues.

10. Potassium reduces lodging problems, increases yield and improves the quality of crops.