| Abstract: | Steer, M. W. 1988. Plasma membrane turnover in plant cells.J.exp. Bot. 39: 987996. Plasma membrane turnover in plant cells occurs as a consequenceof secretion, which incorporates new membrane into the cellsurface and endocytosis, which internalizes surface membrane.Development of methods that provide estimates of the rate ofnew membrane flow to the cell surface has allowed the estimationof turnover times for the plasma membrane. These times rangefrom 10 min for a non-expanding secretory cell to 3 h for anelongating epidermal cell. At least part, if not all, of thereturn route into the cell is via endocytotic vesicles. Quantitativestudies are required to establish the precise level of flowthrough this route. However, turnover times estimated from theabundance of coated patches on the plasma membrane are comparableto those estimated from secretion studies. The effect of thesehigh turnover rates on a number of plasma membrane functionsare discussed and assessed. Key words: Plasma membrane, endocytosis, secretion, plant cells |
