Figure 2.

Dark-grown etr1-7 has enhanced responsiveness to the ethylene agonist propylene in the hypocotyl and root. A, Propylene dose response curves for hypocotyl length of 4-d-old dark-grown wt and etr1-7 seedlings treated with 10 μm AVG. Top, Actual hypocotyl length, including following treatment with 100 μm AgNO₃. Middle, Relative inhibition of hypocotyl length (length/length at 100 μm AgNO₃), with the concentration of propylene causing 50% inhibition (−). Bottom, Ratio of etr1-7 hypocotyl length over wt hypocotyl length for each propylene concentration, with − denoting the predicted ratio if the etr1-7 mutant was not hyperresponsive to propylene. Mean ± se values were determined from 25 to 30 seedlings. B, Propylene dose response curves for root length of 4-d-old dark-grown wt and etr1-7 seedlings. Top, Actual root length. Middle, Relative inhibition of root length (length/length at 0 μL L⁻¹ propylene), with the concentration of propylene causing 50% inhibition (−). Bottom, Ratio of etr1-7 root length over wt root length for each propylene concentration, with − denoting the predicted ratio if the etr1-7 mutant was not hyperresponsive to propylene. Mean ± se values were determined from 25 to 30 seedlings.