Cytochemical Analysis of Callose Localization in Lilium longiflorum Pollen Tubes

Abstract

Callose, a β, 1–3 glucan as a component of plant cells has received sporadic attention. Here, we report an attempt to determine whether aniline blue and lacmoid are indeed specific for visualizing callose. We also re-evaluate, based on a check for stain specificity, the localization of callose in elongating Lilium longiflorum, cv. ‘Ace’ pollen tubes. Specificity of these stains was checked by chemical and enzymatic extraction procedures which solubilize proteins and polysaccharides. Results herein question the generally accepted validity of the fluorescent-aniline blue method for detecting callose. Lacmoid either possesses an affinity for both callose and protein or for callose as a glycoprotein. As for callose localization, the walls of the non-growing region of the lily pollen tube contain callose, probably as a glycoprotein. Presence of the callosicglycoprotein in the wall of the growing tube-tip is dependent on tube length. Callose plugs exhibiting an affinity for aniline blue or lacmoid were never seen. Phase-contrast microscopy revealed non-stainable wall ingrowths in fixed-tubes and free-moving cytoplasmic masses within living tubes.