Scientists have confirmed that a plant species long suspected by Charles Darwin to be carnivorous is indeed part of a new lineage of meat-eating flora, validating the naturalist’s 150-year-old hypothesis. The discovery, published in Nature Communications, centers on Saxifraga candelabrum, a flowering plant native to the high-altitude regions of China’s Tibetan-Qinghai Plateau and Hengduan Mountains. The research, led by Chinese botanist Hang Sun, provides evidence that some members of the Saxifraga genus—known for their sticky, glandular hairs—capture and digest insects to supplement their nutrient intake.
Darwin first proposed the idea in 1875, observing that certain Saxifraga species possessed the physical traits of carnivorous plants, such as adhesive hairs capable of trapping insects. However, no conclusive evidence had been found to support his theory until now. The new study combines field observations, genetic analysis, and biochemical experiments to demonstrate that S. candelabrum not only captures insects but also digests them and absorbs nitrogen, a critical nutrient often scarce in the nutrient-poor soils of its alpine habitat.
The Evidence: From Insect Traps to Genetic Similarities
The research team analyzed 45 samples of S. candelabrum collected from the Tibetan-Qinghai Plateau, a region recognized as the world’s highest and largest plateau. They found that 43 of the samples had insect remains trapped in their glandular hairs, which secrete a sticky substance to ensnare prey. To determine whether the plant could digest its captures, the scientists used fluorescence marking to detect the presence of fosfátase, an enzyme commonly associated with carnivorous plants. The results showed significant fosfátase activity, suggesting the plant actively breaks down its prey.
To further test nutrient absorption, the team fed the plant Drosophila fruit flies marked with a stable isotope of nitrogen. They observed a marked increase in the levels of this isotope within S. candelabrum compared to non-carnivorous plants, confirming that the species can assimilate nutrients from its insect victims.
Genetic Clues Link to Other Carnivorous Plants
Genomic analysis revealed similarities between S. candelabrum and other independently evolved carnivorous plants. The study identified genes associated with insect attraction, digestion, and nutrient absorption that are also present in these species.
Why This Matters: Darwin’s Legacy and Ecological Implications
The Tibetan-Qinghai Plateau, home to S. candelabrum, is a biodiversity hotspot with unique flora and fauna.
Next Steps: Expanding the Search for Carnivorous Plants
Conclusion: A Century-Long Puzzle Solved
For readers interested in following the latest developments, the full study is available in Nature Communications.
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