enzyme-nitrate-reductase involved in the nitrogen metabolism has molybdenum as an essential constituent.
(b) The enzyme-polyphenol oxides, ascorbic acid oxidase etc., have copper as an essential constituent. In various metabolic processes of plants, following micronutrients are involved in many metabolic activities of the plants.
(a) Boron (B) is involved in the formation of pectin in the cell wall in the translocation of carbohydrates, absorption of water and calcium.
(b) Copper (Cu), being an essential component of plastocyanin, is involved in the electron transport role in photosynthesis.
(c) Manganese (Mn) and molybdenum plays an important role in nitrogen metabolism.
(d) Zinc (Zn) helps in the synthesis of Indole Acetic Acid (IAA).
As catalysts in the enzymatic reactions : Zinc, copper and manganese act as enzyme activators for various enzymatic reactions in plant cells. As for example
(a) Zinc activates many enzymes such as lactic dehydrogenase, carboxy peptidases, glutamic acid dehydrogenase and alcohol dehydrogenase.
(b) Manganese acts as an activator for the enzymes
which are involved in decarboxylation reaction and dehydrogenation during respiration