Question

(This lab entailed cutting cross sections of stems, roots, and fruits, then staining them to be examined under microscope)

Explain what the purpose of the two different stains (Aniline Blue and Phloroglucinol Red) are, including what specific chemical compounds they target.

Answer 1

Aniline blue is used to stain collagen, as the fiber stain in Masson's trachoma, as well as to reveal callose structures in plant tissues. It is also used in differential staining. It is soluble dye used as biological dye. In order to demonstrate callose in material we can use longitudinal section of cucurbita stained with Aniline blue. Aniline blue preferentially stain callose.

Chemical compound target- Aniline reacts with strong acids to form salts containing the anilinium ion (C6H5-NH3+), and reacts with acyl halids to form amides.

Phloroglucinol Red- It is used to differentiate and study plant tissue. Like Xylem and Sclerenchyma stain red-orange with phloroglucinol while phloem is always remained unstained. It is also used to see primary xylem in section.

Chemical Compound target- It is a weak triprotic acid and as an enol it principle exist in equilibrium with keto tautomers.

It readily forms aka phloramine in aqueous ammonia at low temperature.

To reaction with water phloroglucinol crystallizes as the dehydrate, which has melting point of 116-117 degree Celsius.