title: Scanning Electron Microscopy (SEM) Protocols for Problematic Plant, Oomycete, and Fungal Samples.
abstract: Common problems in the processing of biological samples for observations with the scanning electron microscope (SEM) include cell collapse, treatment of samples from wet microenvironments and cell destruction. Using young floral tissues, oomycete cysts, and fungi spores (Agaricales) as examples, specific protocols to process delicate samples are described here that overcome some of the main challenges in sample treatment for image capture under the SEM. Floral meristems fixed with FAA (Formalin-Acetic-Alcohol) and processed with the Critical Point Dryer (CPD) did not display collapsed cellular walls or distorted organs. These results are crucial for the reconstruction of floral development. A similar CPD-based treatment of samples from wet microenvironments, such as the glutaraldehyde-fixed oomycete cysts, is optimal to test the differential growth of diagnostic characteristics (e.g., the cyst spines) on different types of substrates. Destruction of nurse cells attached to fungi spores was avoided after rehydration, dehydration, and the CPD treatment, an important step for further functional studies of these cells. The protocols detailed here represent low-cost and rapid alternatives for the acquisition of good-quality images to reconstruct growth processes and to study diagnostic characteristics.
authors.affiliation: Biodiversity and Conservation Department, Real Jardín Botánico, CSIC; mabello2@rjb.csic.es.
authors.forename: M Angélica
authors.initials: MA
authors.lastname: Bello
authors.affiliation: Research Support Unit, Real Jardín Botánico, CSIC.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Ruiz-León
authors.affiliation: Mycology Department, Real Jardín Botánico, CSIC.
authors.forename: J Vladimir
authors.initials: JV
authors.lastname: Sandoval-Sierra
authors.affiliation: Division of Glycoscience, AlbaNova University Center, Royal Institute of Technology (KTH).
authors.forename: Svetlana
authors.initials: S
authors.lastname: Rezinciuc
authors.affiliation: Mycology Department, Real Jardín Botánico, CSIC; dieguez@rjb.csic.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Diéguez-Uribeondo
mesh_terms: D002473:Cell Wall / Q000648:ultrastructure; D005658:Fungi / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D009868:Oomycetes / Q000648:ultrastructure*; D010944:Plants / Q000648:ultrastructure*; D013048:Specimen Handling