A morphometric study on the effects of ethylene treatment in promoting abscission of tobacco flower pedicels.

The ultrastructural changes observed in ethylene-induced abscission of tobacco flower pedicels (Nicotiana tabacum L. ;Little Turkish') were studied by the techniques of morphometric analysis. The surface area of the membranes, relative volume of the organelles, and the number of organelles were determined for both ethylene-treated and control cells. In pedicels exposed to ethylene for 4.5 to 5 hours, abscission was evident within the separation zone. The most significant change in cell structure was observed in the surface area of the rough endoplasmic reticulum which more than doubled with ethylene treatment of the tissue.