Plants have been displaying some unusual behaviors recently, and now a species of tree fern called Cyathea rojasiana has added to the list with its ability to revive itself after death to support its parent plant. Let us explain. Found in the forests of western Panama, Cyathea rojasiana is capable of reanimating its dead leaves, creating roots that extract nitrogen from the soil to continue nourishing the mother plant. While alive, the aging leaves droop downwards so that the middle of the leaf, also known as the rachis, can make contact with the ground. As the leaf dies, the structures inside the rachis, which once transported water to the living parts of the leaf, transform into living roots. These new roots extend into the soil, supplying nutrients to the rest of the plant. “This is a truly unique tissue repurposing, distinct from the processes observed in other ferns,” explained Professor James Dalling, the lead author of the study, in a press release. During the conversion of the fronds to roots, the tree fern may outwardly appear as decaying plant matter. The research team believes this is the first known instance of a fern repurposing the leaves of a plant to self-nourish in this manner. The reason behind this extraordinary behavior is believed to have evolved over geological time. Belonging to an ancient lineage of tree ferns dating back to the Jurassic period, it is thought that the roots developing from dead leaves evolved to extract more nutrients from nutrient-poor volcanic soils. “Panama is a land bridge between North and South America that coalesced 7 million years ago out of an archipelago of islands, and those islands are the result of volcanic activity in the past,” explained Dalling. “In one site we discovered, a layer of volcanic ash several meters deep resembles sand found on a beach. Distinct plants grow there compared to those found elsewhere in the forest reserve.”Due to the slow growth of the tree fern and the substantial energy invested in producing leaves, the plant’s modest height of around 2 meters (6.5 feet) ensures that the aging and drooping leaves always make contact with the ground, facilitating their “zombie” revival. The findings of the research are published in Ecology.
