Mechanical adaptations of a giant kelp
Unusually high extensibility of the kelp Nereocystis luetkeana minimizes breakage by waves and tidal currents. Cellulose fibrils in cortical cell walls have a preferred angle of 60° to the stipe axis; this may be the structural basis of stipe extensibility. Although undamaged plants can sustain drag due to most waves and tides, breakage of single plants occurs most often at flaws in the stipes caused by sea urchin grazing or by abrasion.