Plants don't need salt water. It'll eventually die.
The image shows a phospholipid bilayer. Macromolecules that make up most of the structure that is shown are proteins and lipids. Lipids can make up 20% to 80% of the membrane depending on the location and type of the cell. The rest is made up of proteins.
This type of defense falls under the category of Müllerian mimicry. It is a type of mimicry where two or more species mutually presents themselves as harmful. Müllerian mimicry describes a situation where species have similar warning signals and they share genuine anti-predation.