It is an essential element for plant growth, participating in various processes such as sugar transport, lignification, cell wall structure, carbohydrate metabolism, RNA metabolism, respiration, AIA metabolism, phenolic metabolism, ascorbate metabolism, in addition to having a in cell wall synthesis and plasma membrane integrity.
It is an important nutrient in biological nitrogen fixation in beans. Although it has no direct action on this process, it is an element that activates the starch phosphorylase enzyme, responsible for the synthesis of starch, a reserve substance in seeds and roots.
Deficiency – Initially the youngest leaflets turn dark green, progressing from the apex to the base. Then the leaves become twisted, thick, with the veins of a light green hue. After, necrotic spots and drying out of the growth spots appear. The terminal bud dies. The stem thickens and may show cracks. Deficient plants do not flower and root growth is seriously affected. Irrigation water containing 2 ppm boron is considered harmful to plant development.