Plant resistance to mechanical stress: evidence of an avoidance–tolerance trade‐off

Abstract

Summary• External mechanical forces resulting from the pressure exerted by wind or water movement are a major stress factor for plants and may cause regular disturbances in many ecosystems. A plant's ability to resist these forces relies either on minimizing the forces encountered by the plant (avoidance strategy), or on maximizing its resistance to breakage (tolerance strategy). We investigated plant resistance strategies using aquatic vegetation as a model, and examined whether avoidance and tolerance are negatively correlated.• We tested the avoidance-tolerance correlation across 28 species using a phylogenetically corrected analysis, after construction of a molecular phylogeny for the species considered.• Different species demonstrated contrasting avoidance and tolerance and we demonstrated a significant negative relationship between the two strategies, which suggests an avoidance-tolerance trade-off.• Negative relationships may result from costs that each strategy incurs or from constraints imposed by physical laws on plant tissues. The existence of such a trade-off has important ecological and evolutionary consequences. It would lead to constraints on the evolution and variation of both strategies, possibly limiting their evolution and may constrain many morphological, anatomical and architectural traits that underlie avoidance and tolerance.

Two Simultaneously Occurring Potamogeton Species: Similarities and Differences in Seasonal Changes of Biomechanical Properties

“…The higher discharges and water velocities could cause the adoption of an avoidance strategy to prevent damage or destruction, which was characterised by an increase in shoot elasticity in line with the results of the study by Robionek et al [31]. According to Schutten et al [32] and Puijalon et al [33], aquatic plants are flexible and adjust to living factors by bending with the flow direction. This is an example of an avoidance strategy that helps them survive in different hydrological conditions.…”

Fertile sediment and ammonium enrichment decrease the growth and biomechanical strength of submersed macrophyte Myriophyllum spicatum in an experiment

“…Means with the same letters are not significantly different at P = 0.05 lignification of submersed macrophytes, since they are buoyant in water column and need not to be supported by their strong stems (Usherwood et al, 1997;Xiong et al, 2010). In general, the stems of submersed macrophytes can bend easily to accommodate hydraulic forces exerted on them, and thus make the forces essentially parallel to the shoots (Usherwood et al, 1997;Schutten & Davy, 2000;Schutten et al, 2005;Puijalon et al, 2011). The present results suggest that the tensile properties can represent the mechanical traits of submersed macrophyte stem, and give a reason why most studies just focus on the tensile properties in field and experiments (Schutten et al, 2005;Puijalon et al, 2011;Zhu et al 2012a, b).…”

Adaptation of submerged macrophytes to both water depth and flood intensity as revealed by their mechanical resistance

“…This result indicates that the upper shoots of the five submerged macrophytes were prone to damage by hydraulic forces, but H. verticillata and P. maackianus can withstand drag force for a considerably longer time. Such variations were also observed in ripe aquatic plants (Usherwood et al, 1997;Schutten et al, 2005;Puijalon et al, 2011;Miler et al, 2012). These differences are related to stem tissue structure and cellulose content (Denny, 1988;Sand-Jensen, 2003;Schutten et al, 2004;Zhu et al, 2012).…”

“…The stems of SAV can bend easily to accommodate hydrodynamic forces exerted on them, which make the forces essentially parallel to the shoots (Usherwood et al, 1997;Schutten & Davy 2000;Schutten et al, 2005;Puijalon et al, 2011). Hence, stem tensile properties are key targets for stem breaking resistance, as presented in most studies on SAV (e.g., Brewer & Parker, 1990;Schutten et al, 2005;Puijalon et al, 2011).…”