Little Shop of Horrors: Rheology of the Mucilage of Drosera sp., a Carnivorous Plant

摘要

Drosera sp. (`sundew') are carnivorous plants; they capture insects using tiny drops of mucilage secreted by stalked glands on their leaf laminae. Prey gets trapped by the sticky viscoelastic liquid, initiating a metabolic cascade on the leaf that eventually results in the insect being digested by the plant. The mucilage droplets typically are in the size range of tens of micrometers; at these extremely small sample sizes, complex fluids are usually not amenable to traditional rheometry. We discuss how microrheometric techniques, in particular capillary breakup extensional rheometry (“μ-caber”), can be used to test the nonlinear rheological properties of nanoliter volumes of such small-volume biopolymer samples.