Whole-tree heartwood inducing technique for Dalbergia odorifera

The dried heartwood of Dalbergia odorifera is a very important traditional Chinese medicine. In nature, D. odorifera heartwood forms slowly over several decades, and excessive harvesting has caused large-scale reductions of its wild populations. To date, there have been no studies on artificial methods to induce heartwood formation in trees that have not already begun producing heartwood. We have published a patent for a whole-tree heartwood inducing technique for D. odorifera (the “Dodor-Wit” method); here, we describe and analyze its efficacy. Trees in four plantations in China were treated using this method. After two years, in 2016 and 2017, they were harvested and analyzed. Average heartwood yield per tree was 3,161.95 g. Heartwood induction rate (dry heartwood weight to total dry trunk weight after peeling) was 21.60%. Average volatile oil content per tree was 1.42%. Alcohol-soluble extract of the induced heartwood was 15.77%, exceeding the Chinese Pharmacopoeia standard. This is the first report on the Dodor-Wit method and heartwood induction in D. odorifera trees aged 5–8 years. The heartwood induced by Dodor-Wit satisfies the requirements of the Chinese Pharmacopoeia. The Dodor-Wit method has an important role in solving the extreme scarcity of Chinese medicinal herbs.

Hainan Province, China [1]. The heartwood (resinous wood) of D. odorifera is used to 40 produce high-value furniture, fragrances, and traditional Chinese medicine, for which it is 41 referred to as "Jiang Xiang" [2,3]. Itsheartwood is also widely used in drug therapy in Japan, 42 Singapore, and South Korea. Jiang Xiang, which is listed in the Chinese Pharmacopoeia, 43 has medicinal effects for treating conditions such asblood disorders, ischemia,    Dalbergia odorifera. Panels 1-12: Cross-sections that were taken every 30 cm above the 102 infusion hole. The green dye indicates the distribution of the inducer.

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A brown area and a thin resinous layer appeared inside the trunk within the first week 104 after treatment. Puce-colored wood and a thick resinous layer were observed throughout the 105 trunkafter 12 months. In the present study, we found that black resinous wood formed 106 within24 months of induction treatment (Figs 2 and 3), and this wood reached the quality 107 standards of the Chinese Pharmacopoeia. Therefore, the method successfully induced 108 resinous wood production throughout the entire tree trunk.    Wanning; Jianfeng plantation, Ledong; and Banqiao plantation, Dongfang.

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The heartwood yield of each tree two years after induction ranged from 1,142.8 g to 127 4,707.3 g (Table 2). No resin formed in the natural untreated samples of these plantations.

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The heartwood induction rate (dry heartwood weight to total dry trunk weight after peeling) 129 was 21.60%.
130 Table 2. Yield of induced heartwood two years after application of the Dodor-Wit method 131 induce heartwood formation in Dalbergia odorifera. The trees were cultivated in China.

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The results are presented as means ± SD.   The basic structure of the wood powder of natural heartwood and induced samples 148 was similar. In these two panels, the lowercase letters (a, b, and c), and arrowsrefered to 149 resins, fibers and ducts, respectively. The color of the two sampleswas also similar. Some 9 150 tissue size differences could be caused by the age of the tree (Fig 4).    was extremely close to that of the Chinese Pharmacopoeia standard (Fig 7), with average 223 similarities of 96.6%, 95.5%, and 96.0%, respectively (Table 4). Wanning; S8-S10: three batches from Luoniushan, Haikou.

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The heartwood inducer is injected into the xylem of D. odorifera trees using a 259 transfusion set (Fig 8). Pressure induced by transpiration causes the induction solution to selected, and from this we cut the sapwood sample, which was then weighed. The weight of 294 the resinous wood was then estimated according to the weight of the 30 cm stick (Fig 9). length of a trunk containing heartwood. These formulae assume that the trunk is a 302 symmetrical cylinder, and that the ratio of resinous wood to total wood remains constant 303 throughout the length of the trunk. For each tree, the resinous wood was separated from the 304 white part, weighed, and the heartwood yield was calculated.

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Microscope Observations 306 We used a microscope(Nikon, Eclipse 80i) to study wood sections and wood powder.

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For the wood section method, the wood was sampled at a height of 1.3 m above ground, 308 from natural heartwood (HW treatment), sapwood (CK treatment) and other induced 309 trees.Small blocks of wood were then softened in a water bath at 65°C for more than 12 h.

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The blocks were then sliced into 15 mm thick sheets.