Boron

About 90% of the boron in plants is found in the cell wall, where it plays a fundamental role in cell stability by forming bonds with pectin and polysaccharides. Therefore, it could be said that, along with calcium, B is essential in the metabolic processes of the cell wall.
On the other hand, B is involved in preserving the functions of the cell membrane, by participating in the transport of sugars through the phloem, in the form of borate-type complexes.
Furthermore, boron plays a role in key plant physiological processes, such as cell division and growth, as well as pollination and fruit set, by increasing the viability of pollen grains.
Finally, boron participates in the biological fixation of nitrogen in leguminous plants, facilitating the formation of root nodules.

ABSORPTION
It is absorbed in the form of hydrogen borate ion (H2BO3-), both by the leaves and the roots.

DEFICIENCIES
Boron deficiencies typically occur in acidic, sandy soils with low organic matter content. Boron deficiency is associated with aluminum (Al3+) toxicity, so adequate B in these soils helps reduce Al3+ toxicity.

One of the first symptoms of B deficiency is the inhibition of root growth and development. Furthermore, these roots become more susceptible to pathogen attack due to the weakening of the cell wall.

Cell division also ceases in stems and young leaves. As this deficiency progresses, the plant may experience short internodes, dry shoots, deformities, low pollen viability, and flower abortion and drop.