The effects of abiotic factors on plant health and biomechanics: a mesocosm study on potamogeton crispus

Interactions between flow and vegetation are widely investigated because vegetation is a primary factor controlling channel ecohydraulics, nearshore hydraulics and flood risk. Laboratory experiments are a critical tool in this research area and, to adequately represent the complexity of natural ecosystems, live plants, rather than artificial surrogates, are often used. In the present work, we expose a freshwater macrophyte (Potamogeton crispus) to a range of environmental conditions commonly found in ecohydraulic laboratories to investigate how these affect the level of plant health and associated variations in plant biomechanical properties. This is motivated by a need to understand how deterioration in live plants that are used in flume facilities affects their hydraulic performance and therefore the verisimilitude of the data they provide on flow interactions. Results show that short-medium term exposition to tap water or low irradiance levels is stressful for plants and can induce modifications in their biomechanics, with a potential effect on their hydrodynamic performance.