The effects of downregulating and/or mutating PAL, C4H, pC3H, HCT, and 4CL, as far as the monolignol/lignin pathway was concerned, gave predictable results. PAL, C4H, and 4CL resulted in lower lignin levels overall, with generally deleterious effects (weakening) of the vasculature being noted, albeit not quantified in any way. pC3H, a regulatory branch point to the G/S segments of the lignin-forming pathway, also gave quite predictable results, i. e., significant reductions (up to 64-68% of estimated wild-type lignin levels and/or altered vascular anatomy). Interestingly, for alfalfa, reaction (tension) wood tissue provisionally appeared to be part of a compensatory mechanism to help offset reductions in vascular in­tegrity due to lower lignin contents. No evidence was obtained, though, for “combinatorial” biochemistrybeing in effect to any measurable or significant extent in any of these manipula — tions/mutations. That is, there was no evidence of any shift to formation of non-monolignol phenolic moieties to compensate for reductions in overall lignin amounts. There was, how­ever, a relatively small increase in the level of H-lignin being formed which is considered due to limited substrate degeneracy during a proposed template-assisted polymerization, but only for the pC3H line.