Ecballium

Genus of plants

Speciesbox
|name = Squirting cucumber
|image = Ecballium elaterium1. jpg
|image caption = A fruit of the squirting cucumber
|display parents = 3
|genus = Ecballium
|parent authority = A. Rich. 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. It is grown as an ornamental plant elsewhere, and in some places it has naturalized.

The tissue in the fruit of the Ecballium elaterium that surrounds the seeds is made of large, thin walled cells facilitating the propulsive release of seeds by "squirting". Pressure to expel the seeds is created by the increased concentration of a glucoside called elaterinidin in the sap of the fruit tissue's cells, leading to a turgor pressure of up to 27 atms. The pressure builds up until its force detaches the fruit from the stalk. At the same time, the pericarp contracts and the fruit and seeds are ejected through the hole produced by detachment. The fruit also uses hygroscopic movement and stored elastic energy to squirt the seeds out of the fruit. Sudden movements in plant tissues are prone to different types of mechanical instabilities.

Elaterium is the cucurbitacin extract used in ancient history as a purgative in folk medicine. Extracted from the juice of the fruit of E. elaterium, elaterium was discovered by Stirling in 1835. Elaterin is extracted from elaterium by chloroform and then precipitated by ether. It has the formula C32H44O7. It forms colorless scales which have a bitter taste, with evidence as a poison when consumed through the nose or mouth.