Abstract
We revealed that the cell wall elongation was regulated by adjusting both wall extensibility(Φ) and yield threshold(Y) using cowpea hypocotyls, and found that the y was regulated pH-dependently by yieldin(YLD). The similar regulating phenomenon was only reported in pumpkin hypocotyls. In this report, we examine the mechanical properties of the cell walls of epicotyls of azuki bean (Vigna angularis) by stress-strain experiments. It was found that (i) the φ and the y were also adjusted pH-dependently in the azuki epicotyl cell walls; (ii) the y-adjustment was lost by heat treatments but recovered by reconstitution with azuki wall proteins; (iii) reconstitution with both cowpea and azuki YLDs was insufficient, while another wall protein fraction of the azuki cell walls fully restored the y-adjusting ability.
