Seminar: Rivka Elbaum, Ph.D.

Speaker: Rivka Elbaum, Ph.D, Hebrew University 

Title: Composition and Structures in Plant Cell Walls – Inspiration to Designing Autonomous Walkers 

As non-motile organisms, plants develop means to spread their seed progeny. A very intriguing mechanism involves movements of the seed dispersal unit reacting to diurnal changes in air humidity. These hygroscopic movements are programmed into the material from which the plant tissue is made, constructing a small wooden self-propagating machine. In this talk I will analyze the nano- to macroscopic design principles in awns, which are long hair-like attachments to seed dispersal units. I will demonstrate how the arrangement of cellulose microfibrils set the directions in which a tissue contracts; the hydrophobic cell wall additives set the rates and extent of movement; and the epidermal silica hairs control the interactions with surfaces. Variations and similarities in the chemical composition and design of awns from wheat, storksbill, and oats suggest three seed dispersal strategies that may have ecological consequences.