Figure 4.
Spatial wave frequency (number of waves per unit root length) depends on root elongation rate (mm h-1) and ethylene exposure. Values on the x and y axes describe averages over the 7 d after germination. All plates were tilted at a 45° slope from the vertical. Growth was on 1.5% (w/v) Bacto-agar without or with nutrient supplements (Murashige and Skoog salts or Okada and Shimura salts). The dashed line across each set of data separates sealed versus aerated plates. The equation for the exponential fit of all data is y = 0.16 + 1.6e-20x, R = 0.84, and χ2 = 0.0097. Representative phenotypes across the range of conditions are shown, all viewed from above the plate: A, zero salts, 0% (w/v) Suc, and sealed plate; B, zero salts, 0% Suc, and aerated plate; C, Okada and Shimura salts, 0% (w/v) Suc, and sealed plate; and D, Okada and Shimura salts, 0% (w/v) Suc, and aerated plate. The scale bar = 5 mm.