AFM observation of ultrathin microfibrils in fruit tissues
- 432 Downloads
Polysaccharide microfibrils in fruit tissue of higher plants (strawberry, peach, and rambutan) were examined by atomic force microscopy (AFM). For preserving native cellulose microfibrils, a combination of 2% NaClO2 and 4% NaOH extraction was applied to the materials. This corresponds to mild alkali extractin of holocellulose, and denoted here as weak alkali-resistant polysaccharide, WARP. The amount of neutral sugars corresponded to 53–95% of that of WARP. Glucose was the most abundant in the neutral sugars, being 74–87%. AFM examination of microfibrils dispersed on mica substrate allowed accurate determination of fibril widths as 1.0–2.0 nm. Their straight fibrillar shape and the results of X-ray diffraction and infrared spectroscopy indicate that these fibrils are cellulose. These results constitute direct evidence for existence of ultrafine cellulose microfibrils hitherto assumed from X-ray diffraction and NMR analyses.
KeywordsCellulose microfibril AFM Height measurement Fibril width
We appreciate assistance by Dr. Tomokazu Sasaki for AFM expertise. This work was partially supported by Grant-in-Aid for Scientific Research, No. 19380181.
- Azuma J (2003) Cellulosic hydrocolloid system present in seed of plants. Trends Glycosci Glycotechnol 15:1–14Google Scholar
- Davies LM, Harris PJ (2003) Atomic force microscopy of microfibrils in primary cell walls. Planta 217:283–289Google Scholar
- Franke WW, Ermen B (1969) Negative staining of plant slime cellulose: an examination of the elementary fibril concept. Naturforschung 24b:918–922Google Scholar
- Frey-Wyssling A (1963) Ultrastructure and biogenesis of native cellulose. Fortschritte der chemie organischer naturstoffe 27:1–30Google Scholar
- Green JW (1963) Preparation of cellulose,  wood cellulose. In: Green JW, BeMiller JN, Wolfrom ML (eds) Methods in carbohydrate chemistry, vol III, cellulose. Academic Press, London, pp 9–21Google Scholar
- Hanna RB, Cote WA Jr (1974) The sub-elementary fibril of plant cell wall cellulose. Cytobiologie 10:102–116Google Scholar
- Herth W, Meyer Y (1977) Ultrastructural and chemical analysis of the wall fibrils synthesized by Tobacco mesophyll protoplasts. Biol Cellulaire 30:33–40Google Scholar
- Smith BG, Harris PJ, Melton LD, Newman RH (1998) Crystalline cellulose in hydrated primary cell walls of three monocotyledons and one dicotyledon. Plant Cell Physiol 39(7):711–720Google Scholar