Worm-eating carnivorous plant discovered in Brazil

Washington: Scientists have discovered a new carnivorous plant which has sticky leaves beneath the ground to help it capture and digest worms.

The rare plant Philcoxia minensis is found in Brazil`s tropical savannahs region which is rich in biodiversity and highly in need of conservation.

Although some of the plant`s millimeter-wide leaves grow above ground as expected, strangely, most of its tiny, sticky leaves lie beneath the surface of the shallow white sands on which it grows, said study researcher Rafael Silva Oliveira, a plant ecologist State University of Campinas in Brazil. "We usually think about leaves only as photosynthetic organs, so at first sight, it looks awkward that a plant would place its leaves underground where there is less sunlight," Oliveira was quoted as saying by LiveScience.

"Why would evolution favour the persistence of this apparently unfavourable trait?"

The researchers, who detailed their findings in journal Proceedings of the National Academy of Sciences, suspected the mysterious subterranean leaves of Philcoxia minensis were used to capture animals, as they share a number of traits with known carnivorous plants, such as Venus flytraps.

To see if Philcoxia minensis is carnivorous, the team tested whether it could digest and absorb nutrients from the many nematodes, also called roundworms, which end up trapped on its sticky underground leaves. They fed the plant nematodes loaded with the isotope nitrogen-15, atoms of which have one more neutron than regular nitrogen-14. Then, they placed these Caenorhabditis elegans worms on top of underground leaves of plants kept in a lab setting.

Chemical analysis of the leaves that had been covered in nematodes revealed significant amounts of nitrogen-15, suggesting the plant broke down and absorbed the worms.

The leaves also possessed digestive enzyme activity similar to that seen in known carnivorous plants, suggesting that the roundworms did not decompose naturally, the researchers said.

They speculate that the leaves trapped the worms and then secreted enzymes that digested the worms.

This newfound strategy suggests "carnivory may have evolved independently more times in plants than previously thought," Oliveira said.

"I personally think these findings also broaden up our perception about plants. They might look boring for some people because they don`t move or actively hunt for their food, but instead, they have evolved a number of fascinating solutions to solve common problems, such as the lack of readily available nutrients or water."
PTI