Validation of the petal breakstrength meter. (A) Linearity of standard curve of voltage observed as a function of weight. The fitted linear equation and the correlation coefficient are shown in the upper right hand corner. (B) Data from a typical petal breakstrength assay recording. A wildtype Arabidopsis stage 13  flower-attached petal was gripped by the breakstrength meter petal gripper and then recording was begun. The inflorescence was pulled down (ascending voltage) until the petal was pulled out of the flower (indicated by the triangle). Following this event, the voltage fluctuates briefly due to the damped harmonic motion of the lever following petal pulling. (C) Petal breakstrength assay results. Two petals per flower were assayed from 15 wildtype Arabidopsis thaliana Columbia ecotype plants at the indicated flower positions (n = 30 petals per flower position). Bars represent mean ± standard deviation. Flower 1 is defined as the youngest flower on the inflorescence in which the flower petals are visible.