Search

In recent years, plantations of Aquilaria sinensis in China have been dominated by Qi-nan, yet there remains limited research on the growth evaluation and breeding of these clones. In this study, a multi-point joint variance analysis, an additive main effect and multiplicative interaction (AMMI) model, a weighted average of absolute scores (WAASB) stability index, and a genotype main effect plus a genotype-by-environment interaction (GGE) biplot were used to comprehensively analyze the yield, stability, and suitable environment of 25 3-year-old Qi-Nan clones from five sites in southern China. The results showed that all the growth traits exhibited significant differences in the clones, test sites, and interactions between the clones and test sites. The phenotypic variation coefficient (PCV) and genetic variation coefficient (GCV) of the clones' growth traits at the different sites ranged from 16.56% to 32.09% and 5.24% to 27.06%, respectively, showing moderate variation. The medium–high repeatability (R) of tree height and ground diameter ranged from 0.50 to 0.96 and 0.69 to 0.98, respectively. Among the clones, Clones G04, G05, G10, G11 and G13 showed good growth performance and could be good candidates for breeding. Environmental effects were found to be the primary source of variation, with temperature and light primarily affecting growth, while rainfall influenced survival and preservation rates. Yangjiang (YJ) was found to be the most suitable experimental site for screening high-yield and stable clones across the different sites, whereas the tree height and ground diameter at the Chengmai (CM) site were significantly higher than at the other sites, and the Pingxiang (PX) and Zhangzhou (ZZ) sites showed poor growth performance. The findings suggest that Qi-nan clones are suitable for planting in southern China. There were also abundant genetic variations in germplasm resources for the Qi-nan clones. The five selected clones could be suitable for extensive planting. Therefore, large-scale testing is necessary for determining genetic improvements in Qi-nan clones, which will be conducive to the precise localization of their promotion areas. [ABSTRACT FROM AUTHOR]

Agarwood is a highly sought-after resinous wood for use in medicine, incense, and perfume production. However, the process of agarwood formation is slow. In this study, the induction of agarwood formation in three-year-old Aquilaria sinensis "Qinan" trees through treatment with ethephon, hydrogen peroxide, sodium chloride, distilled water, and wounding was investigated. The results showed that the starch content significantly decreased and that the soluble sugar content significantly increased during the process of agarwood formation, with no significant difference between the different treatment groups. The net photosynthetic rate significantly decreased. Except for the sodium chloride treatment, the total antioxidant capacity and the contents of flavonoids and phenols significantly increased during the process of agarwood formation. The essential oil yield of the ethephon and hydrogen peroxide treatment groups was significantly higher than that of the other treatment groups, with the highest essential oil yield in the ethephon treatment group. Compared to the control group, salt treatment produced the lowest essential oil yield of agarwood. The results indicate that appropriate concentrations of ethephon and hydrogen peroxide can promote the formation of agarwood in A. sinensis "Qinan". [ABSTRACT FROM AUTHOR]

Regulation of abscisic acid (ABA) biosynthesis helps plants adapt to drought stress, but the underlying molecular mechanisms are largely unclear. Here, a drought-induced transcription factor XsAGL22 was isolated from yellowhorn (Xanthoceras sorbifolium Bunge). Yeast one-hybrid and electrophoretic mobility shift assays indicated that XsAGL22 can physically bind to the promoters of the ABA biosynthesis-related genes XsNCED6 and XsBG1 , and a dual-luciferase assay showed that XsAGL22 activates the promoters of the later two genes. Transient overexpression of XsAGL22 in yellowhorn leaves also increased the expression of XsNCED6 and XsBG1 and increased cellular ABA levels. Finally, heterologous overexpression of XsAGL22 in poplar increased ABA content, reduced stomatal aperture and increased drought resistance. Our results suggest that XsAGL22 is a powerful regulator of ABA biosynthesis and plays a critical role in drought resistance in plants. [ABSTRACT FROM AUTHOR]

The heartwood of Dalbergia odorifera T. Chen (D. odorifera) is highly valuable. It was speculated that drought could promote heartwood formation in D. odorifera. To test this hypothesis, we artificially simulated conditions of low and high soil moisture content and investigated whether D. odorifera trees living in habitats with contrasting soil water conditions display distinct heartwood formation. Besides, we performed a preliminary study to explore the possible mechanism of drought affecting heartwood formation in D. odorifera in terms of non-structural carbohydrates (NSC). Higher heartwood formation percentage and heartwood size were observed in drought-treated trees. The heartwood density of drought-treated trees was significantly greater than that of control and the oil content of heavy drought-treated heartwood was significantly higher than that of the other treatments. None of water treatments had a significant effect on the essential oil components of heartwood. Furthermore, the effects of water treatments on the total amount of NSC were very limited; however drought treatments enhanced the transformation of starch to soluble sugars compared to control. This study confirmed the hypothesis that drought could promote the heartwood formation in D. odorifera, not by changing the total amount of NSC but by changing the component proportion of NSC. [ABSTRACT FROM AUTHOR]