Sticky alpine flower confirms Darwin’s 150-year-old carnivorous plant prediction
A flowering plant has been confirmed as a new carnivorous lineage, according to research published in Nature Communications. The findings show that Saxifraga candelabrum can attract, trap, digest and absorb nitrogen from insects, supporting a prediction made by Charles Darwin more than 150 years ago.
While many plants exhibit carnivorous traits such as prey capture, to be formally classified as carnivorous, they must show adaptations for attracting and catching, digesting and absorbing nutrients from prey. In 1875, Charles Darwin posited that some species from the genus Saxifraga—a group of flowering plants typically found in alpine environments—may be carnivorous because of their sticky glandular hairs, which can trap insects. However, there has been a lack of conclusive evidence to support this hypothesis.
Hang Sun and colleagues studied S. candelabrum, which grows in alpine areas of the Qinghai–Tibet Plateau–Hengduan Mountains in China. Field observations and surveys of existing plant samples showed that insect prey were present on the glandular hairs of 43 out of 45 surveyed specimens, with mature plants displaying an average of 71 trapped insects in total (predominantly found on these hairs). The authors then looked for evidence of digestion and nutrient absorption to support their hypothesis.
Fluorescence tagging was used to identify phosphatase activity (a digestive enzyme commonly found in carnivorous plants), suggesting that the plant can potentially digest prey. Drosophila labeled with a stable form of nitrogen were then fed to the plant to analyze whether it could absorb nutrients from prey. The authors observed a notable rise in labeled nitrogen levels among S. candelabrum and control plants from another carnivorous species, in contrast to noncarnivorous controls, supporting the hypothesis of carnivorous behavior in this species.
Finally, genetic analysis found genomic similarities with other independently evolved carnivorous plants, including genes linked to prey attraction, digestion and nutrient absorption. These findings provide strong evidence to support Darwin’s hypothesis that some Saxifraga species may be carnivorous.
Source: phys.org
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Sticky alpine flower confirms Darwin’s 150-year-old carnivorous plant prediction