Callose is a plant polysaccharide. Its production is due to the glucan synthase-like gene (GLS) in various places within a plant. It is produced to act as a temporary cell wall in response to stimuli such as stress or damage.
Formation and function
Callose is laid down at
plasmodesmata, at the
cell plate during
cytokinesis, and during
pollen development. Endothecium contains a substance callose, which makes it thicker. Callose is produced in response to wounding, infection by pathogens,
, and
abscisic acid. When there is wounding in the plant tissue, it is fixed by the deposition of callose at the plasmodesmata and cell wall; this process happens within minutes after damage. Even though callose is not a constitutional component of the plant's cell wall, it is related to the plant's defense mechanism.
Deposits often appear on the
sieve plates at the end of the growing season.
Callose also forms immediately around the developing
and tetrads of sexually reproducing
but is not found in related
apomixis taxa.
Callose deposition at the cell wall has been suggested as an early marker for direct somatic embryogenesis from cortical and epidermal cells of
Cichorium hybrids.
Temporary callose walls are also thought to be a barrier between a cell and its environment, while the cell is undergoing a genetic programming that allows it to differentiate.
This is because callose walls can be found around nucellar embryos during Nucellar embryony.
See also
