Table 1.
Staining Procedures and Respective Detected Metabolites.
| Staining | Substance Detected | Steps | References |
|---|---|---|---|
| 3% ferric chloride | Soluble polyphenols (black precipitates) | 3% ferric chloride (5–15 min) | Perkin et al.32; Johansen3 |
| DMACA | Flavanols (black or dark blue precipitates) | (1) Fixation of sections (5 min; 0.5 g pure caffeine + 0.5 g sodium benzoate + 10 ml distilled water + 90 ml butyl alcohol) (2) Staining in DMACA solution (15–120 min; 1 g DMACA + 50 ml distilled water + 9.2 ml HCl + 50 ml ethyl alcohol) |
McMurrough and McDowell33; Feucht et al.34 |
| Vanillin/hydrochloric acid | Proanthocyanidins (condensed tannins; pink precipitates) | (1) 0.5 g (vanillin) + 100 ml (9% HCl) for 15–30 min (2) Mount in 10% HCla or glycerin acidified medium |
Gardner35 |
| Wiesner’s test | Lignin (pink cell walls) | (1) Solution A: 1 g phloroglucinol + 100 ml of 95% ethyl alcohol (2) Solution B: 18% HCl. (3) Submit the sections to Solution A + B (1:1) for 1–5 min, and mount slides with solution Ba |
Allen and Tollens36; Kisser and Lohwag37; Johansen3 |
| Maule’s test | Lignin (red, orange, or brown cell walls) | (1) 1% KMnO4 (5 min) (2) Wash in distilled water (3) 10% HCl (until the sections become dark brown: 5–10 min) (4) Wash in distilled water (2×) (5) Mount on slides with concentrated ammonium hydroxidea and immediately take photographs (6) Syringyl lignins (S-type) stain red; guaiacyl (G-type), and hydroxyphenyl (H-type) lignins stain brown |
Patten et al.30 |
| Sudan black B | Oils, suberin, wax, cutin (dark blue or black) | Saturated and filtered solution of Sudan black B in 70% ethanol | Jensen38 |
| Astra blue and basic fuchsin | Lignin (fluorescence) | (1) 0.5% basic fuchsin in alcohol (2 min) (2) 5% astra blue (15 sec) (3) 0.5% basic fuchsin in alcohol (20 sec) (4) Wash in distilled water (10 sec) (5) Mount in glycerin 50% |
Kraus et al.39; Souza et al.40 |
| Astra blue and safranin | Lignin (fluorescence) | (1) 1% astra blue and 1% safranin (20 sec) (2) Wash in distilled water (10 sec) (3) Mount with 50% glycerin |
Souza et al.40; Bukatsch41 |
Abbreviation: DMACA, p-dimethylamino-cinnamaldehyde.
a
Be careful: The corrosive mounting solution should not leak out and reach the microscope.