Highly mobile elements concentrate their deficiency symptoms in the mature, lower leaves, since they are easily transported from there to those in formation near the apex (tip) of the shoots. Contrarily, in case of elements with very low mobility, such as boron, the symptoms predominantly occur in the young leaves and the growing points. This is due to the fact that, in order to reach a deficiency status in the plant, those elements cannot be translocated from the mature leaves, where they have been assimilated or incorporated into cell structures.
Boron deficiencies cause general symptoms such as:
- Altered, curly leaves that are generally more fragile.
- Short internodes along with abundant lateral flowering.
- Stems become fibrous, weak and show cracks.
- Fruits are deformed and irregular as a result of incomplete pollination.
- Necrotic root tips affecting root development.