Ecballium

Ecballium is a genus of flowering plants in the family Cucurbitaceae containing a single species, Ecballium elaterium,[1][2] also called the squirting cucumber or exploding cucumber (not the same plant as Cyclanthera brachystachya). Its unusual common name derives from the ripe fruit squirting a stream of mucilaginous liquid containing its seeds as a means of seed dispersal, an example of rapid plant movement.[3]

E. elaterium is native to Europe, northern Africa, and temperate areas of Asia, and is considered an invasive species.[2][4] It is grown as an ornamental plant elsewhere, and in some places it has naturalized.[4][5]

The tissue in the fruit of the Ecballium elaterium that surrounds the seeds is thin walled, facilitating the propulsive release of seeds by “squirting”.[3][6] Pressure to expel the seeds is created by the increased concentration of glucoside and elaterinidin in low volumes of cytoplasm,[citation needed] leading to an osmotic pressure of up to 27 atms.[6] The pressure-building method may depend on the phloem sieve tubes, indicating that the squirting mechanism can be decreased in water stressed conditions.[7]

The fruit also uses hygroscopic movement and stored elastic energy in order to squirt the seeds out of the fruit.[3] This method is done passively where the fruit changes its structure as it dehydrates and deteriorates, causing movement.[3] This movement may be due to coiling, bending, or twisting cells to change its morphological shape as the cells dry.[3] Because drying cells are mostly made up of cell wall, the shape is determined by the cell wall, providing a method for catapulting of seeds to eject them out of the plant.[3][8]