Knowledge

Phosphorus is one of the major nutrients essential for the plant. It is not mobile in the soil and mobile inside the tissues of the plant. Phosphorus plays many physiological roles within the plant, including:

• Phosphorus is part of the nucleic acid structure and plays a major role in many enzymatic reactions.
• Play a vital role in fats and phosphorus compounds synthesis with abundant energy such as: (ADP and ATP).
• play an important role in respiration processes.
• Essential in enzymes synthesis that necessary for the occurrence of energy reactions in photosynthesis and respiration processes.
• increases the percentage of flowering and fruit set.
• Stimulates growth and development root in the plant.
• It has a role in fat and protein synthesis in fruits.

Calcium (Ca) is one of the major secondary nutrients in the plant, so it is not a mobile element in the soil and plant. Therefore, the symptoms of calcium deficiency appear on young leaves and shoot tips. Calcium plays many physiological roles within the plant.

• Calcium has a major role in the formation of cell walls and hardness of plant tissues and increases tolerance of some bacterial and fungal diseases as well as increasing the storage ability of fruits, tubers, and bulbs.
• It has an essential role in pollination and fertilization which, has an effect on pollen tube growth inside the ovary as it reduces the rate of fruit drop and increases fruit set and yield.
• Reduces the toxicity of certain inorganic nutrients such as sodium and magnesium that can accumulate in toxic quantities.
• It plays an important role in the tolerance of adverse weather conditions such as high temperature and frost, as well as sudden exposure to drought or shortage of water in the soil.
• It is very important in cell division and cellular elongation, it is necessary for the continued growth of Meristem tips growth that, responsible for new growths.
• An essential element in the resistance of physiological diseases to fruits.
• Important and necessary in root growth and distributions as well as vegetative growth.
• It has an important role in promoting rhizobium that, fixing nitrogen in legumes plants.

Potassium (K) belongs to the group of macronutrients which are necessary for plant growth. It is one of the mobile nutrients in soil and plant. So Symptoms deficiency appears on older leaves first. Potassium plays an important role in many physiological processes within the plant, including:

• It has an important role in the photosynthesis process.
• Potassium controls the process of opening and closing stomata in the plant, which affects the plant's absorption of water and nutrients.
• Increases plant resistance to environmental stress factors i.e. (high temperature- frost - drought - salinity).
• Potassium is important for protein and starch formation in the plant, as well as activates the enzyme responsible for this process.
• Contributes inactivation of a large number of enzymes (more than 66 enzymes), oxidation, reduction enzymes and protein synthesis and regulation of osmotic pressure within the plant cell.
• Potassium also plays an important role in plant resistance to many fungal and insect diseases by increasing the hardness of plant cell walls.
• It has an important role in increasing the thickness of cellular walls and weakness of vascular tissue appears as a result of potassium shortage.