Yuhua Kong

Rosemary (Salvia rosmarinus) is a world-famous plant frequently subjected to various environmental stresses. Heat Shock Transcription Factor (HSF) has been shown to be essential for plant growth and for resistance to environmental stresses. This study utilized bioinformatics techniques to identify the SrHSF gene family in the rosemary genome. A total of 49 SrHSFs were detected, unevenly distributed across 12 chromosomes. The SrHSF genes were classifiable into 3 subfamilies and contained in 14 subgroups. They were relatively conserved during the evolutionary process based on gene structure and conserved motif analysis. There were 22 kinds of cis-acting elements in the promoter regions of SrHSF genes, mostly related to hormones, stress, growth, and development. The interactions among 16 highly conserved SrHSF proteins were also identified. Gene collinearity analysis showed that 51 segmental duplication events were undergone among 41 SrHSF genes. Ka/Ks ratios were all less than 1, suggesting a purifying selection of SrHSF homologous genes. The expression pattern of SrHSF genes revealed that the majority of them are highly expressed in the secondary stems. After 0.1% MeJA treatment, SrHSF36 and SrHSF11 showed a significant upregulation in leaves. This research provides valuable insights into the functions and regulatory mechanisms of the SrHSF gene family.

Stand age is a key factor for reforestation, and it has an important influence on the sustainable development of artificial forests. In order to reveal the temporal dynamics of soil active carbon (C) and nitrogen (N) in Chinese cypress artificial forests (CAFs) under different stand ages, soil samples were collected from five stands (25, 35, 45, 55, and 65 years old) in rocky mountainous of North China. The characterization of soil active C and N components, like soil microbial biomass C (MBC), microbial biomass N (MBN), dissolved organic C (DOC), dissolved organic N (DON), ammonium-N (NH₄⁺-N) and nitrate-N (NO₃⁻-N), as well as other soil properties were determined. The results showed that with the increase of stand age, the contents of soil MBC, MBN, DOC, DON, NH₄⁺-N and NO₃⁻-N tended to increase first and then decrease, and most of them reached the highest values in 45 years old. Soil active C and N components all reached peak values in June, and all of them showed the most significant variations in 0 ~ 10 cm soil layer (P < 0.01). Correlation analysis revealed that soil active C and N components showed significantly positive correlations with soil total N, total C, the number of microorganism communities and soil water content, as well as litter biomass (P < 0.01). Stepwise multiple regression analysis demonstrated that soil total N was the key controlling factor to soil active C and N components. In conclusion, with the increase of stand ages, soil active C and N components of CAFs did not accumulate all the time, indicating that stand age should be regarded as an important factor for the sustainable management of artificial forests.

To evaluate the effects of land-use types on the temporal dynamics of soil active carbon (C) and nitrogen (N), a field experiment was conducted from five adjacent sites, farmland (FL), abandoned land (AL), Platycladus orientalis artificial forest (PO), Robinia pseudoacacia artificial forest (RP) and Quercus variabilis artificial forest (QV) in the rocky mountainous of North China. Soil dissolved organic C and N (DOC, DON), soil microbial biomass C and N (MBC, MBN), ammonium-N (NH₄⁺-N) and nitrate-N (NO₃⁻-N) were determined during four seasons. The results showed that soil DOC, DON, MBC, MBN, NH₄⁺-N, and NO₃⁻-N contents in PO were higher than other land-use types, especially in QV. Soil DOC, DON, MBC, and MBN contents all showed a higher value in March. Both soil DOC/DON and MBC/MBN showed peak values in June. With the increase of soil depth, soil DOC, DON, MBC, and MBN contents all tended to decrease. Most of soil active C and N components had significant correlations with SOC, TN, AP, soil particle volume fraction and the activities of BG and PROT, while the main influencing factors for soil active C and N components were various. The key contributing factors to soil DOC and MBC was SOC, accounting for 62.6% and 67.9%, respectively. Soil TN was the main affecting factor of soil DON (98.4%) and MBN (75.7%). Soil NH₄⁺-N and NO₃⁻-N were, respectively, affected by volume fraction of silt particles (10.3%) and AP (15.0%). In conclusion, soil active C and N components are more likely to accumulate in the PO soil in spring, indicating tree species and temperature are the key factors driving soil active C and N turnover in this area.