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In this thesis, wood loaded with a silica–titanium (Si-Ti) composite film was prepared using the sol–gel method in order to achieve improved wood with high hydrophobicity and photocatalytic activity under visible light. The factors affecting the structure and properties of the composite film, as well as the optimization process, were discussed. Infrared analysis revealed that the vibrational intensity of Si-O-Si, Ti-O-Ti, and Ti-O-Si telescopic vibration peaks increased with an increase in vinyltriethoxysilane (VETS). Additionally, the number of Ti-O-Ti telescopic vibration peaks also increased with an increase in VETS. Furthermore, the intensity of -NO3, Si-O-Si, and Ti-O-Ti telescopic vibrational peaks was enhanced with a higher dosage of nitric acid. Conversely, the intensity of -OH telescopic vibrational peaks decreased with an increase in drying temperature. XRD analysis showed that nitric acid could promote the transformation of TiO2 from amorphous to anatase, while SiO2 would reduce the grain size of anatase TiO2 and promote the growth of rutile TiO2. Additionally, wood surfaces loaded with Si-Ti composite film changed from hydrophilic to hydrophobic, with significant differences observed between different levels of each factor. The photocatalytic activity of surface-loaded Si-Ti composite films on wood was most affected by the amount of nitric acid, which influenced crystallinity of TiO2 and thus impacted the photocatalytic activity. Furthermore, changes in VTES dosage not only affected the crystalline phase of TiO2 and the grain size of Si-Ti composite film but also influenced the crystallinity of TiO2 through generating SiO2. Finally, based on optimal preparation process (titanium–alcohol ratio of 1:5, titanium–silicon ratio of 1:0.2, titanium–acid ratio of 1:0.5, and drying temperature of 100 °C), wood surfaces loaded with Si-Ti composite film achieved a contact angle up to 125.9° and exhibited a decolorization rate for rhodamine B under UV light reaching 94% within 180 min.

A sapwood tree is a species in which the sapwood does not differ significantly from the heartwood and cannot be classified by shades of color. It is generally accepted that heartwood has a higher economic value than sapwood, but most of the studies related to heartwood formation have focused on heartwood trees, with less research on sapwood trees. In this paper, we take the sapwood tree Schima superba as the research object and analyze the physiological and biochemical changes in the process of heartwood formation by studying the anatomical structure of parenchyma cells, and then further explore the main categories of metabolites and compositional changes. The results showed that during heartwood formation, the parenchyma cells become inactive and the nucleus disappears, while at the same time, the storage substance starch is gradually degraded under the action of enzymes and transformed into secondary metabolites, which include terpenoids, phenols and alkaloids. The accumulation of white and colorless compounds in large quantities in the heartwood, which has some effect on the heartwood color, is an important reason why the heartwood in Schima superba shows normal formation but no difference in color from the sapwood. This study fills a gap in the mechanism of heartwood formation in sapwood trees.

Mangrove plant seedling cultivation is crucial for the protection, management, and restoration of the mangrove ecosystem. In this study, we focused on Kandelia obovata Sheue & al., a typical mangrove, and evaluated nursery cultivation with different combinations of three salinity levels (S1: 0 ppt, S2: 10 ppt, and S3: 20 ppt), three genealogies (EZD, JX, and YZ), and five growth media (M1: 100% loess, M2: 100% sandy, M3: 50% loess + 50% sandy, M4: 40% loess + 40% sandy + 20% peat, and M5: 40% loess + 40% sandy + 20% coir), by measuring the growth parameters such as mortality rate, seedling height, seedling diameter, and biomass partition. These growth indexes were significantly affected by salinity and medium, and genealogies also had significant effects on mortality rate and biomass accumulation. S2 or S3 both had lower mortality and higher growth indexes than S1. M1 was the medium that increased seedling height, diameter, and biomass the most and had the lowest death rate. EZD and JX were also at higher levels than YZ in these indicators, but the difference between them was not obvious. S3, M1, and EZD consistently performed well in fuzzy evaluation and quality assessment (Dickson quality index: 1.179, 1.478, and 1.089, respectively). Furthermore, combinations involving these treatments also produced highly favorable results. This indicates that the quality of seedlings produced under these conditions was high. These results furnish both a theoretical and practical foundation for advancing nursery cultivation techniques and germplasm breeding of K. obovata in mangroves.

To enhance the density and properties of Tsoongiodendron odorum and expand its range of applications, the physical and mechanical characteristics, such as density and hardness, were investigated after impregnating a solution of sodium carbonate and calcium chloride to generate calcium carbonate filler within the wood, followed by thermal compression. The results showed that the surface density of wood was significantly increased by 86.4%. The rate of weight gain gradually increased with sodium carbonate concentration, reaching a maximum of 55.67%. Hardness increased by 85.3%. The optimal treatment process is a compression rate of 5%, a pressing temperature of 170 °C, and a hot-pressing time of 30 min. Microscopic observations revealed that the calcium carbonate was predominantly distributed on the surfaces of wood, while the surface cells exhibited deformation upon compression. Conversely, the cells in the innermost region of the wood remained largely unaltered, thereby achieving a stratified compression effect. Impregnation and compression treatment increases the hardness and bending strength of Tsoongiodendron odorum, but spring-back may occur, and the dimensional stability measures necessitate further investigation and analysis.

Xylem vessels and parenchyma cells perform functions such as water transport and nutrient storage in trees. However, they are highly variable in different trees. Therefore, this study aimed to explore the structural change patterns in vessels and parenchyma cells in the sapwood, transition wood, and heartwood of tree species with different degrees of evolution. The structural characteristics of the two types of cells in the sapwood, transitional wood, and heartwood were measured in six species with different levels of evolution, namely, Michelia macclurei Dandy, Cinnamomum camphora (L.) presl, Erythrophleum fordii Oliv, Melaleuca leucadendron L., Parashorea chinensis Wang Hsie and Tectona grandis L.F. The results showed that the more evolved species had larger earlywood vessel lumen diameters, thicker walls, and wider hydraulic diameters, as well as smaller latewood vessel densities, reflecting better water transport effectiveness and higher safety. From the sapwood to the transition wood and heartwood, the earlywood vessel lumen diameter of the more primitive species tended to be stable and then decrease, while that of the more evolved species gradually decreased. The latewood vessel density of the more primitive species tended to be stable and then increase, while that of the more evolved species tended to be stable. Additionally, the starch grains of the more primitive species were mainly distributed in the axial or ray parenchyma cells of the sapwood, while those of the more evolved species were abundantly distributed in the axial and ray parenchyma cells of the sapwood, and the distribution of the starch grains was reduced in the transition wood and heartwood. From the sapwood to the heartwood, the ray parenchyma cell fraction tended to be stable in the more primitive species, and tended to be stable before decreasing in the more evolved species. The pit density in the horizontal wall of the ray parenchyma cells tended to be stable and decrease in the more primitive species, while in the more evolved species it tended to be stable or decrease before stabilizing. Overall, trees’ vessels have gradually undergone the optimal selection of vessels during evolution, and the structural variation in the parenchyma cells contributes to their nutrient storage and transport.

This study examines the impact of bio-organic fertilizers on the physiological characteristics and leaf nutrient content of “Qi-Nan” agarwood seedlings. The aim is to provide a theoretical foundation for the efficient cultivation of “Qi-Nan”. The experiment was conducted under field conditions using a Randomized complete block design. The control group received no fertilization, while the three fertilizer-treated groups received vermicompost, sheep manure, or microbial organic fertilizer. The results indicate that the application of bio-organic fertilizer significantly promoted the growth of plant height and diameter, increased the contents of soluble proteins, soluble sugar, chlorophyll, and leaf nutrients; and decreased the contents of free proline, peroxidase, malondialdehyde, and other stress indices. Redundancy analysis showed that the main factors affecting the seedlings height and diameter were free proline, chlorophyll, total nitrogen, and total potassium. Principal component analysis and membership function analysis revealed significant variations in growth, physiological characteristics, and nutrient content among the three fertilizer groups and the control group, with vermicompost > microbial organic fertilizer > sheep manure > no fertilization. In conclusion, biological organic fertilizer significantly promotes the growth of “Qi-Nan” seedlings, and vermicompost is the most effective fertilizer in this experiment.

In this study, we analyzed the mechanism and the process of fungal-induced agarwood formation in Aquilaria sinensis and studied the functional changes in the xylem structure after the process. The microscopic structure of the white zone, transition zone, agarwood zone, and decay zone of 12-and 18-months of inoculation A. sinensis xylem was studied. The distribution of nuclei, starch grains, soluble sugars, sesquiterpenes, fungal propagules, and mycelium in xylem tissues was investigated by histochemical analysis. The results show that the process of agarwood formation was accompanied by apoptosis of parenchyma cells such as interxylary phloem, xylem rays, and axial parenchyma. Regular changes in the conversion of starch grains to soluble sugars, the production of sesquiterpenoids, and other characteristic components of agarwood in various types of parenchyma cells were also observed. The material transformation was concentrated in the interxylary phloem, providing a structural and material basis for the formation of agarwood. It is the core part of the production of sesquiterpenoids and other characteristic products of agarwood. Compared with the A. sinensis inoculated for 12 months, the xylem of the A. sinensis inoculated for 18 months was more vigorous. There were no significant differences between the 12 and 18 months of inoculation in terms of sugars and agarwood characteristic products. In production, harvesting after 12 months of inoculation can improve harvesting efficiency.

Agarwood is a highly economically important medicinal herb with widespread uses; however, the difference between the biological activities of artificial and wild agarwood is unclear. In this study, the alcohol-soluble extracts of agarwood produced by fungi and natural agarwood were used to determine the differences between the overall biological activities. The antioxidant ability (the clearance rates of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radicals, and total reducing power), anti-acetylcholinesterase, and anti-α-glucosidase activity were determined by ultraviolet-visible spectrophotometry. The results indicated that with 2 mg/mL alcohol-soluble extracts, the scavenging DPPH radical rates of the artificial agarwood samples were 93.74–102.31% of that of the wild agarwood, and the ABTS+ radical clearance rates of the artificial agarwood samples were 75.38–95.52% of that of the natural agarwood. With 3.5 mg/mL alcohol-soluble extracts, the artificial agarwood samples had a total reducing power of 63.07–80.29% of that of the wild agarwood. With 4 mg/mL alcohol-soluble extract, the acetylcholinesterase activity inhibition rates of the artificial agarwood samples were 102.56–109.16% of that of the wild agarwood. With 1 mg/mL alcohol soluble extracts, the α-glucosidase effect inhibitions rates of the artificial agarwood samples were 68.32–100.39% of that of the wild agarwood.

Heartwood has a high economic value because of its natural durability, beautiful color, special aroma, and richness in active ingredients used in traditional Chinese medicine. However, the mechanism of heartwood formation remains unclear. Dalbergia odorifera was selected as the object of research to analyze this variation in the chemical composition of sapwood, transition zone, and heartwood as well as to elucidate the relationship between this variation and the formation of heartwood. The variation of secondary metabolites was analyzed using gas chromatography-mass spectrometry and ultra-high performance liquid chromatography–mass spectrometry, the variation of lignin was analyzed using Fourier transform infrared spectroscopy and ultraviolet visible spectrophotometry, and the variation law of mineral elements was analyzed using atomic absorption spectrophotometry. The results demonstrated that contents of characteristic secondary metabolites in Dalbergia odorifera were mainly distributed in heartwood (84.3–96.8%), increased from the outer to inner layers of the xylem, and sudden changes occurred in the transition zone (the fourth growth ring). The Dalbergia odorifera lignin can be identified as typical “syringyl–guaiacyl (S–G)” lignin, and the color darkened from the outside to the inside. The results demonstrated that there were more benzene rings and conjugated C=O structures in the heartwood. Additionally, the variation of minerals in the xylem was related to elemental types; the average concentrations of Mg, Ca, Fe and Sr were higher in the heartwood than in the sapwood, whereas the concentrations of K and Zn were higher in the sapwood than in the heartwood owing to the reabsorption of elements. The concentrations of Na and Cu were similar in the heartwood and sapwood. The composition and structural characteristics of secondary metabolites, lignin, and mineral elements in the three typical xylem regions (sapwood, transition zone and heartwood) of Dalbergia odorifera changed. The most abrupt change occurred in the narrow xylem transition zone, which is the key location involved in heartwood formation in Dalbergia odorifera.