Cell wall composition determines handedness reversal in helicoidal cellulose architectures of <i>Pollia condensata</i> fruits
Yin Chang, Rox Middleton, Yu Ogawa, Tom Gregory, L. Steiner, Alexander Kovalev, Rebecca H. N. Karanja, Paula J. Rudall, Beverley J. Glover, Stanislav N. Gorb, Silvia Vignolini
Abstract
fruit; both left- and right-handed helicoidal cell walls are found in neighboring cells of the same tissue. By simultaneously studying optical and mechanical responses of cells with different handednesses, we propose that the chirality of helicoids results from differences in cell wall composition. In detail, here we showed statistical substantiation of three different observations: 1) light reflected from right-handed cells is red shifted compared to light reflected from left-handed cells, 2) right-handed cells occur more rarely than left-handed ones, and 3) right-handed cells are located mainly in regions corresponding to interlocular divisions. Finally, 4) right-handed cells have an average lower elastic modulus compared to left-handed cells of the same color. Our findings, combined with mechanical simulation, suggest that the different chiralities of helicoids in the cell wall may result from different chemical composition, which strengthens previous hypotheses that hemicellulose might mediate the rotations of cellulose microfibrils.