|Macadam, J - UTAH STATE U|
Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 14, 2002
Publication Date: N/A
Technical Abstract: Ferulate deposition, 5-5-coupled diferulate cross-linking, and lignification of primary walls has been correlated with reduced extensibility and growth of coleoptiles. We examined relationships among ferulate, diferulate, and p-coumarate accretion with changes in the segmental elongation rate (SER) of leaf blades from slow and rapid elongating genotypes of tall fescue (Festuca arundinacea Schreb) grown in controlled environment chamber. SER was not influenced by ferulate deposition but SER decelerated as 8-5-, 8-O-4-, 8-8-, and 5-5-coupled diferulic acids accumulated in cell walls. SER rapidly slowed and stopped with the deposition of p-coumarate, which is associated with lignification in grass cell walls. Accretion of ferulate, diferulates and p-coumarate continued after growth ended, into the later stages of secondary wall formation. The concentration of 8-coupled diferulates dwarfed that of the commonly measured 5-5-coupled isomer, suggesting that the latter dimer is a poor indicator of diferulate cross-linking in cell walls. Further work is required to clearly demonstrate the role of diferulate cross-linking and p-coumaroylated lignin in halting leaf growth in grasses.