Fig. 1. Leaf abscission in response to ethylene. The percentage of petioles that had abscised in response to a gentle touch was recorded at several intervals of time for Hobbit 87 and Hobbit 87 etr1–1 explants exposed to 25 µL L^–1 ethylene in air at 25°C. The petioles were debladed before ethylene treatment. The abscission of petioles for the primary (unifoliate) leaves and true (trifoliate) leaves were recorded separately.