Seed Coat Ruthenium Red Staining Assay The goal of this protocol is to assay for defects in synthesis/secretion/release of seed coat mucilage by ruthenium red staining of mature whole seeds.
The mucilage secretory cells of the Arabidopsis seed coat synthesize and secrete a large quantity of primarily pectinaceous mucilage to a ring-shaped apical domain during their differentiation. This makes them an excellent model system to identify genes involved in both cell wall synthesis and secretion (et al., 2000). When wild-type seeds are incubated in ruthenium red stain, hydrated mucilage is extruded from epidermal cells and a ‘halo’ of red-stained mucilage is observed surrounding the seed (Western et al., 2000). Reduced mucilage staining may result from defects in cell wall biosynthesis, secretion, or impaired release upon hydration.