A Statistical Growth Property of Plant Root Architectures
Root architectures are population-similar and have Gaussian spatial densities. (a) Log-log plot showing that a moments-derived measure of architecture size (standard deviation, -axis) is highly correlated with a common measure of size (convex hull volume, -axis). (b) Step one of the population-similarity test, plotting the log of (-axis) versus the log of architecture size (-axis) for all 1645 architectures. Only even moment orders between 0 and 20 are plotted. Each root architecture has one dot for each moment order. Straight lines are the least-squares fit for each moment order. (c) Step two of the population-similarity test, plotting the moment order (-axis) versus the slope of the corresponding line from panel (b) (-axis). For each moment order, error bars correspond to 99% confidence intervals for each corresponding regression line in panel (b). Error in the legend shows the standard error, computed using bootstrapping. (d) Plots of the intercepts of the lines in panel (b) versus moment order. The intercepts of the data (roots) closely overlaps with the intercepts for a Gaussian spatial density function truncated at 3.3 standard deviations. Intercepts for the uniform and truncated Gaussian spatial densities were computed analytically .