Possible Clues:

• Substance in plants — so cull eel (anag)
• Substance in wood pulp
• Main constituent of plant cell walls
• About 90% of cotton fiber
• Small room where, say, you get rid of dietary fibre
• Polysaccharide consisting of chains of glucose monomers
• Tissue in room you finally drop
• Chief constituent of all plant tissues
• Polysaccharide
• Room you reportedly forfeit - film-makers use it