You don’t want to be in front of the Chinese witch hazel when its fruit bursts open. The plant—long known for its anti-inflammatory properties—can fire seeds at more than 12 meters per second, and with the force of a bullet fired from a 19th-century gun. Now, for the first time, researchers have revealed how remarkable behavior works.
Chinese witch hazel (Hamamelis Mollis) grows a hard, fuzzy fruit that ripens about a year after the plant is pollinated. Using MRI scans, researchers discovered that when the plant is ready to release its seeds, the outer layer of the fruit shrinks, while the fleshy inner portion both shrinks and expands. This constricts the middle section of the fruit, forcing the seeds to pop out with an audible crack, the team reports today in the Journal of the Royal Society Interface.
Chinese witch hazelnuts form a hard, strange seed for about a year. MRI studies revealed that when the plant was ready to spread seed, the upper membrane of the fruit was thinner and the more fleshy inner parts expanded and expanded. This causes the middle part of the fruit to jam. After a certain point, the seed rises with an audible sound.
The thrown seed rotates about 26,000 times per second. This allows seeds to maintain their acceleration and direction, just like bullets. According to the researchers, these seeds can fly up to 18 meters. Other types of nuts up to 6 meters can throw seeds.
The reason for the plant’s development of this mechanism is that it wants to find new areas in crowded and high-tree forests.
The research was published in the Journal of the Royal Society Interface.