Optimisation and investigation of the use of 2,2-dimethoxypropane as a dehydration agent for plant tissues in transmission electron microscopy.

After obtaining initially inconsistent results using 2,2-dimethoxypropane (DMP) to dehydrate pea root and stem segments for transmission electron microscopy, it was found that consistent total dehydration of 3-mm pea root and 1- and 3-mm pea stem lengths was only obtained after 2 15 min exposure to DMP, i.e., much longer than originally recommended (L. L. Muller and T. J. Jacks, 1975, J. Histochem. Cytochem., 23, 107). Satisfactory dehydration of a variety of plant tissues was achieved after 2 15 min dehydration in DMP, and no differences in cell ultrastructure were observed between ethanol and DMP-dehydrated samples following three different fixation procedures (glutaraldehyde/OsO4, acrolein/OsO4, and KMnO4). The value of DMP in the retention of cell contents during dehydration was assessed in procedures for the localization of (1) rat liver peroxisomal soluble catalase using 3,3-diaminobenzidine and (2) Na+ K+ and Cl by precipitation techniques in Suaeda maritima leaf segments.