Sulfur

Sulfur is present in the structure of important amino acids such as cysteine ​​and methionine, so it is a fundamental part in the formation of proteins in which, in addition to this role, it participates in the conformation of proteins thanks to the disulfide bridges (SS) that are formed between the different amino acids present in them.

Cysteine ​​is found in glutathione, which in turn forms phytochelatins, proteins capable of chelating heavy metals such as cadmium, thus acting as a defense mechanism for plants against these toxic agents. Glutathione is also necessary for defense against pathogens.

Sulfur is also a structural element of thiamine or vitamin B1, an essential compound of the coenzymes that catalyze the oxidation of pyruvic acid in the respiratory cycle.

ABSORPTION

Sulfur is absorbed by the roots and leaves in its inorganic form as the SO4-2 ion. It is then reduced and incorporated into organic compounds, where it is mineralized by the action of microorganisms.

It can also be absorbed through the stomata of leaves in the form of sulfur dioxide (SO2), an atmospheric pollutant resulting from the combustion of coal, wood, and oil. SO2 reacts with water inside cells to form bisulfite (HSO3), which displaces magnesium from chlorophyll and consequently reduces photosynthesis.

DEFICIENCIES

Sulfur deficiencies are uncommon, as sufficient amounts are found in the soil. However, if this deficiency occurs, plants experience stunted growth and become stiff and brittle. Sulfur deficiency can be confused with nitrogen deficiency, due to widespread leaf chlorosis. However, unlike nitrogen deficiency, symptoms of nitrogen deficiency initially appear in young leaves, due to the immobility of sulfur.