...David R. Smyth Many plants show some form of helical growth, such as the circular searching movements of growing stems and other organs (circumnutation), tendril coiling, leaf and bud reversal (resupination), petal arrangement (contortion) and leaf blade twisting. Recent genetic findings have...

... orientations. We propose that a microtubule-dependent process and SPR1/SPR2 act antagonistically to control directional cell elongation by preventing elongating cells from potential twisting. Our model may have implicit bearing on the circumnutation mechanism. * Author for correspondence (e...