Figure 1.

A model proposing the role of arabinose rich pectin polymers in stabilising the cell wall against water loss. (A) Pectin consisting of short arabinan chains in the hydrated state, (B) pectin consisting of short arabinan chains in the dehydrated state; (C) pectin consisting of long arabinan chains in the hydrated state; (D) pectin consisting of long arabinan chains in the dehydrated state. The likelihood of irreversible tight junctions (e.g., egg boxes) forming in arabinan poor cell walls during dehydration is demonstrated in (B) while the reversible buffering effect of arabinan rich cell walls is proposed in (D) as would possibly occur in Myrothamnus flabellifolia. For simplicity arabinan chains not participating in the buffering interactions between the RGI backbone chains have been shortened to two arabinose residues in length. Note in (A) and (B) all arabinan chains are two arabinose residues in length.