Large quantities of tobacco stalks residues are generated and discarded as crop waste or combusted directly every year. Thus, we need to find an appropriate way to dispose of this type of waste and recycle it. The conversion of biomass waste into electrode materials for supercapacitors is entirely in line with the concept of sustainability and green. In this paper, tobacco-stalk-based, porous activated carbon (TC) was successfully synthesized by high-temperature and high-pressure hydrothermal pre-carbonization and KOH activation. The synthesized TC had a high pore volume and a large surface area of 1875.5 m² g⁻¹, in which there were many mesopores and interconnected micro-/macropores. The electrochemical test demonstrated that TC-1 could reach a high specific capacitance of up to 356.4 F g⁻¹ at a current density of 0.5 A g⁻¹, which was carried in 6M KOH. Additionally, a symmetrical supercapacitor device was fabricated by using TC-1 as the electrode, which delivered a high energy density up to 10.4 Wh kg⁻¹ at a power density of 300 W kg⁻¹, and excellent long-term cycling stability (92.8% of the initial capacitance retention rate after 5000 cycles). Therefore, TC-1 is considered to be a promising candidate for high-performance supercapacitor electrode materials and is a good choice for converting tobacco biomass waste into a resource.

Solanesol, which accumulates predominantly in the leaves of tobacco plants, has medically important bioactive properties. To investigate the genetic basis of solanesol in tobacco (Nicotiana tabacum), the solanesol contents of 222 accessions, 206 individuals from an N. tabacum Maryland609 (low-solanesol) × K326 (high-solanesol) F2 population and their corresponding F1 self-pollinations, were determined using ultra-performance liquid chromatography. Genome-wide quantitative trait locus (QTL) and association analysis were performed to identify QTLs and markers associated with solanesol content based on simple sequence repeat molecular markers. A total of 12 QTLs underlying solanesol content were mapped to seven linkage groups (LGs), with three of the QTLs (QTL3-1, QTL21-6, and QTL23-3) explaining 5.19–10.05% of the phenotypic variation. Association analysis revealed 38 significant marker-trait associations in at least one environment. The associations confirmed the QTLs located on LG3, LG10, LG14, LG21, and LG23, while new elite makers were located on 11 additional LGs, each explaining, respectively, 5.16–20.07% of the phenotypic variation. The markers LG14-PT54448, LG10-PT60114-2, LG10-PT60510, LG10-PT61061, and LG-21PT20388 may be useful for molecular-assisted selection of solanesol content in tobacco leaves. These results increase our understanding of the inheritance of solanesol-associated genes and will contribute to molecular-assisted breeding and further isolation of regulatory genes involved in solanesol biosynthesis in tobacco leaves.

Organic materials are widely used to enhance soil organic carbon (SOC) storage, but their comparative effects and underlying mechanisms in saline-alkali soils remain unclear. A field experiment was conducted in the Yellow River Delta to evaluate the effects of different organic materials on SOC sequestration and soil structure in saline-alkali paddy soil. Four treatments were included: mineral fertilizer alone (NPK), NPK plus organic fertilizer (NPKC1), NPK plus biochar (NPKC2), and NPK plus rice straw (NPKC3). All organic materials significantly improved soil structure compared with NPK alone, as indicated by higher mean weight diameter(MWD) and a greater proportion of particulate organic carbon (POC) relative to mineral-associated organic carbon (MAOC). Among the treatments, NPKC1 markedly increased microbial biomass carbon (MBC) and showed the highest SOC mineralization rate, indicating enhanced microbially mediated carbon turnover. In contrast, NPKC2 increased aromatic and phenolic carbon contents and exhibited the lowest mineralization rate, reflecting the greater chemical stability of biochar-derived carbon. NPKC3 also promoted SOC accumulation, but its effects on carbon stabilization and sequestration efficiency were intermediate between those of NPKC1 and NPKC2. The results showed that NPKC2 achieved the highest SOC storage, whereas NPKC1 showed the greatest carbon sequestration efficiency (CSE). Overall, long-term application of organic materials promoted SOC sequestration in saline-alkali paddy soils through distinct pathways: organic fertilizer mainly enhanced microbial transformation and sequestration efficiency, biochar favored long-term SOC accumulation through chemically stable carbon forms, and rice straw showed moderate effects on both SOC storage and stabilization.