Effect of ethylene on plasma membrane density in kidney bean abscission zones.

Plasma membranes from abscission zones of kidney bean seedlings were isolated on sucrose density gradients using cellulase and KCl-stimulated ATPase as marker enzymes. Following treatment of the seedling explants with 50 microliters per liter ethylene, an increase in the buoyant density of the plasma membrane fraction from 1.165 to 1.175 grams per cubic centimeter was observed. Such a change is consistent with the loss of lipids from the senescent cells of the abscission zone.