Rafael Silva Oliveira, of the State University of Campinas in Sao Paulo, Brazil, with his colleagues, has stated they have proof these plants qualify as carnivores, by digesting the nematodes.
Philcoxia has a network of tiny underground leaves, each about the size of a pinhead, able to grab sunlight through the white sandy soil. They contain glands secreting a sticky mucus that traps tiny worms and starts to digest them. The plants are found in the tropical savannas of Brazil, which are areas rich in biodiversity.
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, said Oliveira. The scientists have detailed their findings in the Proceedings of the National Academy of Sciences.
In order to test if they could digest and absorb nutrients from nematodes, the scientists placed the worms on top of underground leaves of plants kept in a lab. A chemical analysis of the leaves covered in nematodes revealed significant amounts of nitrogen-15, which suggested the plant broke down and absorbed the worms.
Undoubtedly, the most unique feature about how Philcoxia kills its prey is the underground placement of leaves that function as effective nematode traps, said Oliveira. It's a great example of how plants, which can't move to find food and water, are able to develop interesting mechanisms to deal [with] extreme environments,' he added.