Which statement describes the role of borax in Grocott's Methenamine Silver staining?

• A. It acts as a buffer
• B. It acts as oxidizing agent
• C. It stains silver
• D. It acts as a fixative

Answer: (A)

The key idea is that borax acts as a buffering agent in Grocott's methenamine silver staining. The development step relies on silver ions being reduced to metallic silver at sites where aldehydes were created by the periodic acid oxidation. Keeping the developing solution at a stable, alkaline pH with borax helps prevent nonspecific background and ensures silver deposition occurs mainly at the target structures, giving clear, selective black deposits on fungi and related tissue elements. Borax isn’t an oxidizing agent, it doesn’t stain silver itself, and it isn’t a fixative; its job is to stabilize the reaction environment so the stain develops properly.