One of the essential trace elements for the growth and development of plants is zinc. Also called zinc, it has the chemical symbol Zn and is required by plants in small quantities, as with the rest of the microelements.

Clarify that, in Spanish, the words zinc and zinc are accepted as valid. However, the expression zinc is the most consistent with the origin of the word and, therefore, with its chemical symbol Zn.

Zinc fertilization should be taken into account. In the case of its scarcity in cultivation, it causes negative effects on the correct development of the plant, as well as on its excess, but in this case, it even becomes a toxic element for it.

Functions of zinc in plants

The functions of zinc in plants are multiple. Some examples are:

• Its prominent role in carbohydrate synthesis during photosynthesis.
• Its participation in the transformation of sugars into starch.
• By intervening in the metabolism of hormones by regulating the level of certain auxins.
• Performance in the processes of maturation and production of seeds.
• Favoring the improvement of pollen (its formation, pollination, viability, and fertility).
• Helping the maintenance and integrity of cell membranes.
• Its influence on the elongation of shoots and development of leaves.

Some shielding is also attributed to the tolerance of plants to pathogens, especially those in soil, as well as being essential in the defense systems of cells against highly toxic free radicals.

Zinc in the soil

The total zinc (Zn) content of soils normally ranges between 10 and 100 ppm and can reach values of up to 300 ppm in some soils. But these quantities do not necessarily indicate that the availability for the plant of this element is guaranteed.

Zinc can be found in different forms in soil, including:

• Constituting part of the minerals of the soil. In the form of sulfides (sphalerite), carbonates (smithsonite), and silicates (hemimorphite).
• Fixed in the crystal lattice of some clays (montmorillonite, mineral of the group of silicates).
• Forming stable complexes with soil organic matter.
• Adsorbed in the soil change positions.
• Dissolved in the soil solution.

In what form does the plant take zinc?

As we advance, not all the existing zinc in the soil can be taken up by the plant, so it is very important to know in what state it is to know if it really acts as a macronutrient.

The roots absorb Zn in the ionic form Zn2+. On the other hand, the pH of the soil influences its state, so that in acidic soils there is a greater release of Zn2 + to the solution, coming from insoluble forms. On the contrary, in alkaline conditions, the fixation of Zn2+ in the clay-humic complex is favored, as well as the formation of zinc hydroxide unassimilable by the plant.

Under this premise, the acidification of the rhizosphere increases the availability of Zn2 + and therefore the absorption by the roots is high.

Symptomatology of zinc deficiency in citrus fruits

The lack of a macronutrient can be different depending on the species of plant in which it is produced. Thus, to be more concrete and serve as an example, we refer to the symptoms of zinc deficiency in citrus fruits.

Its deficiency in zinc manifests itself mainly in the leaves. Its limbus yellows in the areas between the secondary deviations. Instead, the areas attached to the main and secondary nerves remain greener.

This intensity of yellow hue in the affected leaves is greater the more pronounced the deficiency. When the plant suffers from a strong lack of zinc, usually these leaves tend to be smaller, with a narrower and pointed shape. In addition, they usually fall prematurely.

Another effect of zinc deficiency in citrus fruits is the one that manifests itself in their budding. In this case, the development of budding is reduced, the stems become thinner, and the internodes are shortened.

Main products for the correction of zinc deficiencies

Technically, zinc sulfate, zinc oxide, zinc nitrate, zinc chelate, zn polyflavonoid, and zn lignosulfonate are the main compounds for correcting zinc deficiencies.

For correction or ensuring that a zinc deficiency does not occur, JISA has different formulations of high efficiency.