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R O Gardner

Publications and source records attributed to R O Gardner.

2 recordsLinked to original sources

An overview of botanical clearing technique.

Clearing techniques are outlined with reference to their action on the chemical constituents of plant tissue. The most general technique would include pretreatment with solvents, dissolution of protoplasm, dissolution of other substances, bleaching, infiltration with a dense fluid, and staining. Extensive chemical changes go on during these steps and may prevent satisfactory clearing, an important example being the discoloration of phenolic compounds. Rational design of clearing methods for the chemically distinct cell types and tissue seems a likely future development.

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Vanillin-hydrochloric acid as a histochemical test for tannin.

Condensed tannin (leucoanthocyanins and catechins) can be demonstrated in fresh plant sections with saturated alcoholic vanillin followed by addition of concentrated HCl. Bright red vanillin-tannin condensates are formed immediately. Preparations may then be made permanent by mounting in a 1:1 mixture of Hoyer's medium and concentrated HCl. Some fading and loss of tannin occurs. The phloroglucinol-HCl test for lignin can also be made permanent with this acidic mountant.

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