Table 1 Main Physiological Functions of Essential Nutrients in Crops Main Physiological Functions of Nutrients Carbon, Hydrogen and Oxygen (C, H, O) When crops undergo photosynthesis with the participation of light energy, carbon, hydrogen and oxygen are used to make carbohydrates-sugar. Sugar further forms important compounds, such as starch, fiber, protein and fat. Oxygen and hydrogen also play an important role in the biological redox process of crops. Nitrogen (N) is the main element of protein, and protein is the basic substance of cell protoplasm. Nitrogen is also the main component of chlorophyll, enzymes (biocatalysts), nucleic acids, vitamins and alkaloids. Phosphorus (P) is a component of nucleic acid and nucleotide, and it is the main component of protoplasm and nucleus. Nucleotide and its derivatives are participants in the transformation of organic matter and energy in crops. Many phosphorus esters (a storage form of phosphorus) and many enzyme molecules in crops contain phosphorus, which has an important influence on the metabolic process of crops. Potassium (K) can promote photosynthesis and activators of various enzymes, which is beneficial to the synthesis of carbohydrates, fats and protein, so it can improve the quality. Calcium (Ca) has a certain influence on the metabolism of carbohydrates and nitrogen-containing substances in crops, and can eliminate some ions (such as ammonium, hydrogen and hydrogen). Calcium mainly exists in the middle layer of cell wall in the form of calcium pectin, which can enhance the resistance of crops to pests and diseases. Magnesium (Mg) is a component of chlorophyll and phytate (the storage form of phosphoric acid), which can promote the activities of phosphatase and glucose invertase and is beneficial to the conversion of monosaccharides, so it plays an important role in carbohydrate metabolism. Sulfur is a component of amino acids, protein, vitamins and enzymes. Sulfur is also involved in the formation and redox of chlorophyll in the body. Iron is an indispensable condition for chlorophyll formation, and directly or indirectly participates in the formation of chloroplast protein. Many respiratory enzymes in crops contain iron, which can promote crop respiration and accelerate physiological boron oxide. (b) Boron is involved in meristem differentiation, floral organ development and seed formation. Manganese (Mn) Manganese is an activator of enzyme, which is closely related to crop photosynthesis, respiration and nitrate reduction.
Table 1 Main Physiological Functions of Essential Nutrients for Crops (Continued)-/Main Physiological Functions of Nutrients Copper (Cu) is the core element of various oxidase activating groups in crops and plays an important role in catalyzing redox reactions in crops. Copper can improve the stability of chloroplasts. Copper-containing enzymes are related to the synthesis of protein. Zinc (Zn) zinc is a component of carbonic anhydrase in crops, which can promote the decomposition of carbonic acid and is related to the processes of photosynthesis, respiration, carbohydrate synthesis and transportation of crops. The formation of auxin in crops is also related to zinc. Molybdenum (Mo) Molybdenum is a component of nitrate reductase in crops and participates in the reduction of nitrate nitrogen. Molybdenum can also improve the nitrogen-fixing ability of nitrogen-fixing bacteria. Chlorine (Cl) participates in photosynthesis, regulates cell osmotic pressure, and can enhance the resistance of crops to some diseases. Nickel (Ni) Nickel is a component or activator of urease, hydrogenase and malate dehydrogenase, which is closely related to nitrogen metabolism, respiration and nitrate reduction of crops. Nickel is necessary for the normal function of DNA and RNA. Nickel can also promote seed germination and delay aging.