The Spiral Growth of Single Cells

Abstract

Cylindrical sporangiophores of Phycomyces twist about their long axis as they elongate. Simultaneous measurements were made of rates of elongation and rotation about the axis, at 15[degree] and at 25[degree]C. The temp. coefficients for this interval for rotation are higher than for elongation, which is taken as evidence that the spiral orientation of growth is due to a resolution of at least 2 forces. Cells raised to 27.7[degree]C may cease rotation or reverse its direction, although elongation continues.