The present invention relates to the role of plant phenylcoumaran benzylic ether reductase (PCBER) (1) in lignification and growth of plants. More particular, the invention relates to plants in which PCBER has been down-regulated, resulting in a lower lignin content, higher soluble phenolics, a higher resistance to plant pathogens and a higher biomass production of the plant. These characteristics are maintained under elevated CO.sub.2 concentrations.