Polynucleotide, DNA constructs and methods are disclosed for the modification of cellulose content in plant tissues. Plants are transformed with constructs encoding either an active Anabaena sp. sucrose synthase gene or a soybean nodule sucrose synthase gene, which leads to increased cellulose content when over-expressed under the control of a cambium/xylem preferred promoter. Plant transformants harboring an Anabaena sp. or a soybean nodule sucrose synthase gene demonstrated increased content of cellulose, a trait that is thought to improve woody trees for cellulose extraction during pulping and papermaking.
