Abstract Detail
Developmental and Structural Section Meyer, Robert W. [1], Vazquez-Cooz, Iris A. [1]. Differences in the microfibril angle of libriform fibers and fiber tracheids in 15 species of Acer. THIS research applied the soft-rot method to measuring the microfibril angle (mfa) in fiber tracheids and libriform fibers in fifteen species of Acer (maple). Decay cavity angles caused by Chaetomium globosum (a soft-rot fungus) in libriform fibers are significantly larger than in fiber tracheids. For example, in radial sections of Acer floridanum the average mfa obtained from a sample of 100 soft-rot cavities for libriform fibers was 23.3 degrees (95% C.I. ±1.4) and for fiber tracheids was 11.7 degrees (95% C.I. ±1.2). For Acer nigrum, the average mfa of the libriform fibers was 16.4 degrees (95% C.I. ±1.07) and for the fiber tracheids was 6.4 degrees (95% C.I. ±0.64). With polarized light the areas of libriform fibers are darker than the fiber tracheids, which also suggests that mfa is different. At four weeks of exposure to C. globosum the libriform fibers were more intensely attacked than the fiber tracheids, suggesting a difference in cell wall chemistry.
Our earlier studies on Acer have shown morphological and chemical differences between libriform fibers and fiber tracheids. Libriform fibers have simple pits with elliptical shapes that are predominantly concentrated towards the center of the fiber, while in the fiber tracheids the pits are more round and distributed approximately along the fiber length. Intercellular spaces are common among the libriform fibers and some have spiral thickenings. Differences in stain reactions and fluorescence indicate that libriform fibers differ in lignin concentration and chemical composition from fiber tracheids – syringyl lignin concentration is greater in libriform fibers. The differences in mfa supplement the differences in morphology and chemistry between libriform fibers and fiber tracheids in Acer species studied.
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1 - SUNY College of Environmental Science and Forestry, Construction Management and Wood Products Engineering, One Forestry Drive, Syracuse, New York, 13210, USA
Keywords:
Acer
Chaetomium globosum
fiber tracheid
libriform fiber
maple
microfibril angle
soft-rot cavity.
Presentation Type: Oral Paper:Papers for Sections
Session: 22-14
Location: 312/Bell Memorial Union
Date: Monday, July 31st, 2006
Time: 5:15 PM
Abstract ID:96 | 