transmitted to other parts of the plant when it's attacked or damaged. signals and plants can also be electrical. when a particular stimulus reaches a certain threshold they can trigger what's known as an action potential and bang there's a reaction. to suffer. mentally it's comparable to what happens in human cells if there are certain types of electrical signals that so far have only been found in plants flunking fun and rewarding. scientists call these other signals system potentials they've observed how an impulse triggers changes and the voltage at the so membrane in simple terms the positive charge outside the cell increases but instead of the membrane reacting with a sudden discharge when stimulated as happens with an action potential the increased voltage is passed on systemically from cell to cell from the leaf to leaf.