Changes in Non-Structural Carbohydrates, Wood Properties and Essential Oil During Chemically-Induced Heartwood Formation in Dalbergia odorifera .

The highly valuable heartwood ofDalbergia odoriferaT. Chen, known asJiang Xiangin traditional Chinese medicine, is formed very slowly, and there is a need to better understand the process and promote heartwood formation. Chemical induction is considered to be one of the promising methods to induce heartwood formation. However, to date no method has been proved effective forD. odoriferaas little is known about biochemical and physiological changes during heartwood development. Three potential heartwood induction substancesviz.acetic acid, sodium chloride, and hydrogen peroxide solutions were injected into the trunk ofD. odoriferato determine the effect on heartwood formation and physiological activity. Non-structural carbohydrates, lipids, wood properties, and essential oil were assessed in the post-treatment period. As also observed in the formation of natural heartwood, chemical-inducedJiang Xiangproduction was accompanied by sapwood dehydration, non-structural carbohydrates consumption, and synthesis of heartwood substances. As the heartwood substances accumulated, basic density and essential oil content increased gradually, therebyJiang Xiangwas finally produced. In this process, physiological parameters of discolored sapwood gradually evolved to resemble those of natural heartwood. Hydrogen peroxide-inducedJiang Xiangwas closest to natural heartwood, and the essential oil components met the standards for high-qualityJiang Xiang, while the induction effects of acetic acid and sodium chloride were unsatisfactory. Thus, this study indicates that hydrogen peroxide has the potential to induceJiang Xiangproduction inDalbergia odorifera.