Helical growth

Asymmetry can be caused by changes in pectin or through mutation and result in left- or right-handed helices.

[6] Helical growth in single cells, such as the fungi genus Phycomyces or the algae genus Nitella, is thought to be caused by a helical arrangement of structural biological material in the cell wall.

[7] In mutant thale cress, helical growth is seen at the organ level.

Analysis strongly suggests that cortical microtubules have an important role in controlling the direction of organ expansion.

[8] It is unclear how helical growth mutations affect thale cress cell wall assembly.