Chloroplast ultrastructure in leaves of Urtica dioica L. analyzed after high-pressure freezing and freeze-substitution and compared with conventional fixation followed by room temperature dehydration

摘要: In this article, we report on the adaptation of high-pressure freezing and freeze-substitution (HPF-FS) for ultrastructural analysis leaf tissue with special emphasis chloroplasts. To replace gas in intercellular spaces, a mixture water methanol (MeOH) was employed. We compared three different supplements FS--osmiumtetroxide, uranyl acetate, safranin--with regard to preservation ultrastructure chloroplasts other cellular compartments. The results show that (i) replacement air within spaces by 8% (v/v) MeOH has no influence chloroplasts, (ii) undulation membranes frequently observed after conventional preparation specimens does not occur during chemical fixation but room temperature dehydration, (iii) acetate or osmium tetroxide employed FS are superior over safranin.