Why does the fruit of this tree explode? Science explains how the assacu launches seeds tens of meters

Why does the fruit of this tree explode? Science explains how the assacu launches seeds tens of meters jojimenezb / iNaturalist Imagine walking through the Amazon Rainforest and, suddenly, hearing a boom similar to that of a small firecracker. The sound may not be caused by a breaking branch or a falling tree, but by the fruit of the assacu (Hura crepitans), a species that has developed one of the most curious seed dispersal mechanisms ever recorded among plants. ? Also follow Terra da Gente on Instagram When it ripens and dries, the fruit ruptures explosively, releasing the seeds dozens of meters away. The phenomenon, known to science as explosive dehiscence, is an evolutionary strategy that increases the species' chances of survival by spreading its descendants far from the mother tree. Assacu belongs to the Euphorbiaceae family and occurs naturally in floodplain forests, igapó areas and riparian forests in the Brazilian Amazon. In the country, it is found in the states of Acre, Amazonas, Amapá, Pará, Rondônia and Roraima. See more news from Terra da Gente, on g1: EDUCATION: Biologist dedicated to raising stingless bees and bringing children closer to nature MUSHROOMS: For the first time, Brazil creates an official list of fungi threatened with extinction SAPEADA: Activity takes visitors to observe amphibians in nature Explosion planned by evolution At first glance, the rupture of the fruit seems like an accident of nature. But exactly the opposite happens. During ripening, the capsule loses water and accumulates mechanical stress in its compartments. When this pressure reaches the limit of the structure, the fruit breaks suddenly and each segment works like a kind of spring, propelling the seeds away. Assacu fruit, or acaçu dummy_2004 / iNaturalist According to Embrapa Amazônia Oriental, they can reach up to 45 meters away from the mother plant. For biologist and specialist in tropical botany Henrique Bertole, it is a sophisticated survival strategy. "The explosive dehiscence of the fruit is not a mere spectacle of nature, but sophisticated evolutionary engineering. By accumulating mechanical tension during drying and releasing the seeds, the assacu ensures that its seedlings have access to light and nutrients without directly competing with the mother tree." According to the expert, spreading the seeds in this way also reduces losses caused by predators and fungi that tend to concentrate close to the adult plant. "Furthermore, spreading the seed in this way dilutes the risk of attacks by predators and specific fungi that tend to concentrate near the main trunk." International studies also show that, under certain conditions, the explosive opening of the fruit can launch the seeds at speeds close to 70 meters per second, around 250 km/h, placing the assacu among the most extreme examples of this type of dispersal in tropical trees. See what's highlighted in g1:

A living fortress The tree's trunk is full of thorns panthicha / iNaturalist The explosive fruit is not the species' only striking feature. The assacu can reach around 40 meters in height and has a trunk covered in conical thorns, a characteristic that earned it popular names such as devil's tree. But the plant's main line of defense goes beyond appearance. Whenever you get a cut, it releases a highly irritating white latex, capable of causing damage to the mucous membranes, intense burning in the mouth and throat, nausea, vomiting and inflammation in the eyes. Raw seeds are also toxic and can cause poisoning when ingested. For Bertolini, it is a set of adaptations built throughout evolution. "The assacu is a true living fortress, perfectly adapted to ward off threats. Starting with the trunk, whose conical spines discourage any animal from climbing it. Added to this, we have an impressive chemical arsenal: when the plant suffers the slightest cut, it releases a latex that is severely irritating to the mucous membranes. It is an implacable defense strategy against herbivores." Between poison and medicine Paradoxically, the same substances responsible for the tree's toxicity also arouse the interest of science. A scientific review published in 2025 brought together 17 studies carried out in different countries and showed that assacu contains several bioactive compounds present mainly in the latex, seeds and skin. Research in the laboratory and in experimental models investigates antioxidant, antimicrobial, antiparasitic, anti-inflammatory and antitumor activities, as well as possible applications in the treatment of diabetes. Assacu is a tree that can reach 40 meters in height codiferous / iNaturalist Despite the promising results, the researchers themselves warn that there is still not enough evidence to recommend any therapeutic use in humans. This is because the same compounds responsible for the biological effects are also associated with the plant's high toxicity. According to Bertolini, it is precisely this delicate balance that makes the species so interesting for research. "There is enormous scientific interest in assacu because its phytochemical composition is very complex, harboring bioactive metabolites such as diterpenes, lectins and flavonoids. In the laboratory, these compounds have already demonstrated anti-inflammatory, antitumor activities and even action against the parasite that causes malaria." While this process still requires many studies, the assacu continues to attract attention for another reason: its extraordinary reproduction strategy. In a forest where thousands of species compete for space, light and nutrients, evolution found a simple and efficient solution — transforming the fruit itself into a catapult capable of launching the future of the species tens of meters away. VIDEOS: Highlights Terra da Gente See more content about nature on Terra da Gente

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