Abstract: Nowadays, it is difficult for the naturally-growing wood to meet the growing demand in China. Thus, plantation wood plays a more and more important role in alleviating the contradiction between supply and demand. Plantation area in China ranks first in the world, but the quality of wood is poor, which limits its application. Therefore, it is becoming more and more important to cultivate good quality plantation wood. Genetic engineering can from the fountainhead improve the quality of the plantation wood in the limited forestland. In order to provide reference for further research and application of genetic engineering to the quality of plantation wood, this paper reviewed the effects of genetic engineering on wood chemistry, structure and physical & mechanical properties of plantation wood. For wood chemistry, the effects of genetic engineering are mainly on the changes in lignin content, proportion of lignin monomer, and the contents of cellulose, hemicellulose and other chemical compositions. The research on reducing lignin content achieved the most rapid development. For wood structure, the effects are mainly on the changes of cell morphology and microfibril orientation, and therefore the improvement of the quality of fibers, and the quality of pulp is expected. For wood physical and mechanical properties, the effects on density, shrinkage, and strength with many target genes of obvious impacts are reported. At present, genetic engineering improvement of plantation wood quality is still in the primary stage and there are still some problems to be solved. 1) The cell wall formation of transgenic plants is under precise regulation of time and space. Therefore, the impacts of time and environmental factors on the transgenic plants, the stability of genetic engineering improving wood quality, and the cultivation environment and measures that conducive to the stable expression of target genes should be deeply studied. 2) Genetic engineering can improve wood properties, but the degree of improvement differs. Thus, it is necessary to find the genes that can be stably inherited and the methods to improve the expression level of target genes. 3) The fundamental research on the genetic improvement of wood properties is far from sufficiency. The variation of the improvements needs to be further studied, more target genes that can make stable improvement need to be found and a complete and reliable basic database needs to be established.

Key words: plantation wood, genetic engineering, wood chemistry, wood structure, physical and mechanical properties of wood