Desmidiales, there are pores in the cell wall which allow the cell to extrude a layer of mucilage for protection.

Several Zygnematophyceae contain genes involved in protection from desiccation that appear to have been derived by horizontal gene transfer from bacteria; the genes are found in plants, Zygnematophyceae, and bacteria, but no other organisms. The genes may have helped to enable plants to make the transition