Pinus koraiensis is classified as a second-class protected wild plant in China, recognized for its considerable economic and ecological importance. However, progress in functional research and breeding applications for this species has been hindered by the lack of an effective genetic transformation system. The purpose of this study was to develop a reliable and efficient genetic transformation system for a Pinus koraiensis embryonic callus using somatic embryogenesis technology. The Pinus koraiensis embryonic callus and β-glucuronidase (GUS) were employed as the reporter gene in an Agrobacterium-mediated transformation to investigate critical transformation factors, including antibiotic type and concentration, Agrobacterium bacterial solution concentration, infiltration, and co-cultivation times. The findings indicated that the proliferation of the Pinus koraiensis embryonic callus was substantially inhibited by 10 mg·L−1 of Hygromycin (Hyg), and a remarkable 93.42 ± 2.13% efficiency was achieved with an OD600 absorbance value of 0.6 during transformation. Two days of optimal co-cultivation yielded a transformation rate of 82.61%, with the resistant embryonic callus exhibiting a high GUS staining rate of 88.89%. Resistant somatic embryos were effectively obtained following the optimized protocol. This research contributes to the advancement of seed resource breeding and genetic enhancement for Pinus koraiensis, establishing a solid foundation for the investigation of gene functions specific to this species.
Fully utilizing regional resources such as marine sand, coral, and desert sand, along with a diverse range of solid wastes from industries, agriculture, and urban areas, not only effectively reduces the costs and carbon footprint of construction activities but also contributes to achieving sustainable development in the building sector. Despite earlier studies focusing on the feasibility of solid waste as lightweight aggregates, the comprehensive evaluation of the performance of alternative aggregates in such innovative materials as geopolymers and ultra-high-performance concrete remains significantly limited amid their rapid development. Therefore, this paper concentrates on a thorough exploration of regional sand and gravel resources, as well as efficient and value-added approaches to incorporating solid wastes from industries, agriculture, and urban areas as alternative aggregates in construction. It provides a comprehensive review of the physical properties of alternative aggregates and their impacts on the workability, mechanical properties, and durability of concrete. Additionally, the paper offers a detailed assessment of the production processes and performance of sintered and cold-bonded artificial aggregates. This research provides valuable insights for researchers and practitioners in the fields of construction, sustainable waste management, resource conservation, and recycling.
Functional membranes that are both robust and porous with selective wettability find widespread application in oil/water separation processes. This study used polyacrylonitrile (PAN), surfactant-modified cellulose nanocrystals (H-CNC) and polyvinylpyrrolidone (PVP) as the raw materials to prepare a nanofibrous membrane (HCNC/PPAN) with a strong loess-beam-like structure using the electrospinning and sacrificing template strategy. Surfactant adsorption enabled stable dispersion of H-CNC within the polymer matrix. The tensile strength and Young's modulus were 7.46 +/- 0.36 MPa and 150.66 +/- 33.12 MPa, respectively, which represent an increase by 3.15 times and 1.89 times when compared to the corresponding values of the PAN membrane. The H-CNC/PPAN membrane obtained a good pore size distribution after removing PVP by water etching, as a result of the formation of furrows and micro-meso-pores. Moreover, the etching process effectively improved the mechanical properties of the membranes. Based on the presence of hydroxyl and amide groups on the membrane surface, the membrane displayed pre-wetting induced underwater superoleophobicity and underoil superhydrophobicity. Driven by gravity, an ultra-high permeation flux of 7210.51 L & sdot;m � 2 & sdot;h- 1 and a separation efficiency of over 98.93% were achieved. Thanks to its excellent oil repellency and good resistance to acid, alkali and salt, the HCNC/PAN membrane is highly sustainable and has broad potential applications in the field of oil/water separation.
Rhododendron aureum is identified as a vulnerable species in China. The establishment of an in vitro regeneration system assists significantly in species protection. Here, an in vitro regeneration system was developed using both direct and indirect organogenesis pathways. The role of thidiazuron (TDZ) in different developmental stages was also investigated. The leaves of wild-harvested R. aureum plants were used for callus induction after hydroponic cultivation. The optimal formula was found to be woody plant basal medium (WPM) supplemented with 0.5 mg·L−1 TDZ and 0.5 mg·L−1 3-indolebutyric acid (IBA), while the optimal formula for the subculture and induction of adventitious buds was WPM containing 0.1 mg·L−1 TDZ and 0.5 mg·L−1 IBA. The leaves from tissue-cultured seedlings were then used for the induction of bud clusters. An association was observed between the differentiation of bud clusters and the ratio of auxin and cytokinin. The optimal formula for the induction of bud clusters was WPM containing 0.5 mg·L−1 TDZ and 0.1 mg·L−1 IBA, yielding a 50% induction rate and the maximum number of buds. Higher concentrations of TDZ were found to be beneficial for bud proliferation, while a lower concentration was conducive to stem elongation. The optimal formula for subculture was WPM containing 0.1 mg·L−1 TDZ and 0.5 mg·L−1 IBA, while that for stem elongation was WPM supplemented with 0.002 mg·L−1 TDZ and 0.5 mg·L−1 IBA. Only IBA was found to be necessary for rooting, with increased IBA concentrations leading to an increased number of roots and earlier root formation, with larger callus areas; thus, an IBA concentration of 1.0 mg·L−1 was found to be optimal for the rooting of R. aureum. After hardening the seedlings for two days, a substrate composed of vermiculite and peat soil in a 10:1 ratio was identified as a transplantation formula. This system provides directions both for the protection of endangered species and the promotion of industrial development.
This study investigated the effects of carbon nanofibers (CNFs) and PVA fibers on the mechanical properties, impact resistance, abrasion resistance, and microstructure of ultrafine fly ash (UFA) high-performance concrete when used alone and in blends. CNFs and PVA fibers were incorporated at 0.1 %, 0.2 %, and 0.3 %, respectively. The results of the study revealed that CNFs and PVA fibers significantly enhanced the mechanical strength and cracking toughness of concrete, whether added individually or in blends. The enhancement of cracking toughness was more prominent in the mixed systems with higher fiber additions. Notably, the combined use of CNFs and PVA fibers can also significantly enhance the impact resistance and abrasion resistance of concrete. When the fiber addition is appropriate, the impact energy consumption is significantly increased. The optimal incorporation ratio was 0.1 % by volume of PVA fibers and 0.3 wt% by mass of CNFs. at this ratio, the impact resistance of concrete was improved by 128.24 % and the abrasion resistance was improved by 18.17 % compared to the control group. Further scanning electron microscopy (SEM) and mercury-in-pressure (MIP) tests revealed that the mixing of CNFs and PVA fibers effectively enhanced the densification of the concrete matrix, increased the amount of its hydration products, and strengthened the bonding of the fibers to the matrix.
The hybridization of nanomaterials and macroscopic fibers is currently a popular topic. The aim of this study was to explore the application potential of incorporating carbon nanofibers (CNFs) into concrete and to analyze the effect of CNFs dispersant on concrete slump and early strength. Polyvinyl alcohol (PVA) fibers and CNFs were used to prepare composite fiber-reinforced (CNFs-PVA) concrete to improve the continuity of concrete properties at the micron/nanometer scale. The engineering properties such as compressive strength, flexural strength and resistance to chloride ion erosion performance of the concrete were investigated, and the microstructure of concrete was characterized using X-ray diffraction (XRD), scanning-electron microscopy (SEM), and X-ray computed tomography (X-CT). The results showed that CNFs could improve the early strength. The combined use of CNFs and PVA increased the 28-day compressive and flexural strength by 23.38% and 28.73%, respectively, compared to the control group. Correspondingly, the electric flux and Migration rate of chloride ions (DRCM) were minimized. From the SEM and XRD test results, it is clear that CNFs and PVA fibers can: (i) bridge low-density C-S-H to form higher-density C-S-H gels, (ii) form longer chain-like fibers with enhanced load transfer and chloride binding capacity, (iii) act as internal curing agents to enhance hydration at the interface, (iv) promote the for-mation of the aluminum phase hydration products and calcium carbonate phase, and (v) CNFs and PVA refine the pore size by increasing the gel pores and reducing the percentage of microcracks. The combined results indicate that the improved performance of CNFs-PVA is due to the combined effect of bridging and nucleation of hy-dration products by CNFs, adsorption of hydration products by CNFs-PVA, and promotion of pore filling by the generated hydrides such as calcium carbonate and ettringite. These findings provide new insights for the design of high-performance concrete materials.
The aim of the study was to systematically investigate effect of the particle size of fly ash on the resistance to chloride ion penetration of concrete as well as the workability and mechanical properties. Two different particle sizes, i.e., D50, particle size <15.22 mu m (FA) and D50, particle size <3.12 mu m (ultrafine fly ash, UFA) were used for the investigation. The use of PVA fibers helps minimize issues such as brittleness. The mechanical properties of polyvinyl alcohol fiber-reinforced ultrafine fly ash (PVA-UFA) composites as well as the resistance to chloride ion penetration were investigated. The results showed that UFA has a higher engineering value in terms of work performance improvement. UFA is useful in improving the mechanical properties of concrete and the resistance to chloride ion penetration at all ages. The optimum content of UFA is 25%. The 28 d flexural strengths of PVA-UFA specimens were 11.01% higher than those of control group. Moreover, the electric flux and DRCM decreased by 10.96% and 42.58%, respec-tively. The flexural strength and chloride ion penetration resistance of the composite material with PVA fibers were improved compared with those of the single UFA material owing to their better microstructure. Therefore, PVA-UFA can be applied in coastal highways, bridges, and other structures.
Fraxinus mandshurica is a widely used greening and ornamental tree species. However, its genetic transformation system has been hampered by problems such as low transformation efficiency, among others, which can hinder research related to molecular breeding and the analysis of functional genes. Thus, in this study, a novel genetic transformation method for efficient transformation of the embryonic callus of Fraxinus mandshurica was investigated. The method was optimized in terms of factors such as antibiotics, infection solution concentrations, co-culture time, and somatic embryo maturation. The results indicated that the optimal antibiotic concentration was 10 mg·L−1 of hygromycin (Hyg). At this point, the callus proliferation multiple was only 0.12. The highest transformation efficiency was found to be 93.93% when the absorbance of the infection solution concentration at OD600 was 0.4. Interestingly, transformation efficiency was found to be highest (77.9%) at 48 h of co-culture, with a GUS staining rate of 88.23%. The medium for somatic embryo maturation of transformed callus was half-strength MS medium (MS 1/2) containing 60 g·L−1 polyethylene glycol, 1 mg·L−1 abscisic acid, 400 mg·L−1 casein enzymatic hydrolysate (CH), 20 g·L−1 sucrose, 1 g·L−1 activated charcoal, and 5 g·L−1 gellan gum. The medium for somatic embryo germination was MS ½, containing 0.2 mg·L−1 of N-(Phenylmethyl)-9H-purin-6-amine(6-BA) and 5.0 mg·L−1 of gibberellin (GA). These results are of significance for the verification of the gene function and future genetic improvement of Fraxinus mandshurica.
Drought has severe effects on plant growth, forest productivity, and survival throughout the world. Understanding the molecular regulation of drought resistance in forest trees can enable effective strategic engineering of novel drought-resistant genotypes of tree species. In this study, we identified a gene, PtrVCS2, encoding a zinc finger (ZF) protein of the ZF-homeodomain transcription factor in Populus trichocarpa (Black Cottonwood) Torr. & A. Gray. ex Hook. Overexpression of PtrVCS2 (OE-PtrVCS2) in P. trichocarpa resulted in reduced growth, a higher proportion of smaller stem vessels, and strong drought-resistance phenotypes. Stomatal movement experiments revealed that the OE-PtrVCS2 transgenics showed lower stomata apertures than wild-type plants under drought conditions. RNA-seq analysis of the OE-PtrVCS2 transgenics showed that PtrVCS2 regulates the expression of multiple genes involved in regulation of stomatal opening and closing, particularly the PtrSULTR3;1-1 gene, and several genes related to cell wall biosynthesis, such as PtrFLA11-12 and PtrPR3-3. Moreover, we found that the water use efficiency of the OE-PtrVCS2 transgenic plants was consistently higher than that of wild type plants when subjected to chronic drought stress. Taken together, our results suggest that PtrVCS2 plays a positive role in improving drought adaptability and resistance in P. trichocarpa.
为了解转录因子bHLH在长白落叶松(Larix olgensis)中的功能,探究该基因在长白落叶松不同组织中及不同逆境胁迫下的表达特性,从长白落叶松根、茎和叶3个不同部位的转录组数据中获得bHLH34基因全长序列,并设计引物,克隆得到长白落叶松bHLH34基因,其完整的开放阅读框(ORF)长度为696 bp,共编码231个氨基酸.构建亚细胞定位表达载体,瞬时转化毛果杨(Populus trichocarpa)原生质体,在激光共聚焦显微镜下观察显示,Lob-HLH34基因定位在细胞核内.系统进化树分析结果显示,长白落叶松与云杉(Picea asperata)、卷柏(Selaginella tamariscina)树种该基因的亲缘关系较近.利用qRT-PCR技术分析了bHLH34基因在长白落叶松中的组织表达特异性和应对非生物胁迫的表达.结果 表明LobH34基因在长白落叶松的根、茎、叶中均有表达,其中在茎部表达量最低,在叶中相对表达量最高.LobHLH34基因在NaC1、PEG和ABA处理时,不同器官中的表达量也有所不同.推测长白落叶松bHLH34基因参与了植物的生长、发育、响应逆境胁迫的过程,且在不同器官中具有特异性.
S1Fa-like transcription factors (TFs) are small molecular weight proteins that contain both nuclear localization and DNA binding domains. However, the functions of S1Fa-like TFs are poorly understood. In the present study, we identified the S1Fa-like TFs from the Populus trichocarpa genome, which revealed two S1Fa-like TF genes, PtS1Fa1 and PtS1Fa2. PtS1Fa1 and PtS1Fa2 expression was suppressed by drought and salt stress, and was also significantly altered by ABA, MeJA, or SA treatment. Both PtS1Fa1 and PtS1Fa2 are nuclear proteins. Transgenic P. trichocarpa plants overexpressing PtS1Fa1 and PtS1Fa2, respectively, were generated. The plants overexpressing PtS1Fa2 showed increased fresh weight, chlorophyll content, and root length and weight compared with those in wild-type (WT) P. trichocarpa under drought conditions. Meanwhile, these phenotype traits of plants overexpressing PtS1Fa1 were similar to those of WT plants. Furthermore, overexpression of PtS1Fa2 reduced the malondialdehyde (MDA) content, electrolyte leakage, H2O2 and O2- contents, and increased superoxide dismutase (SOD) and peroxidase (POD) activities. The expression of SOD and POD was also induced by PtS1Fa2. However, overexpression of PtS1Fa1 failed to affect any of these physiological parameters or SOD and POD gene expression. These results suggested that PtS1Fa2 plays a role in drought tolerance, and confers drought tolerance by increase antioxidant activity to reduce reactive oxygen species (ROS) accumulation.
Larix olgensis or larch is an economically important coniferous tree species with rapid growth in the early stages, strong adaptability, and a short time to harvest. The genetic improvement of larch has garnered considerable attention in recent years for reclaiming timber forests. However, traditional breeding methods are largely ineffective for achieving rapid genetic improvement of L. olgensis. Studies show that the efficiency of plant regeneration can be improved by optimizing somatic embryogenesis. On this basis, we devised a stable, fast and efficient Agrobacterium-mediated genetic transformation method using suspended embryogenic calluses as explants and β-glucuronidase as the reporter. We evaluated the effects of the Agrobacterium load, co-culture period, and addition of acetosyringone and transformant screening antibiotic on the transformation efficiency. In addition, we tested the pCAMBIA 1300-PtHCA 2-1 promoter-GUS binary expression vector, which contains the GUS gene ORF under the control of Populus trichocarpa high cambial activity PtHCA 2-1 promoter, and observed the tissue-specific expression of the GUS gene in the somatic embryos of transgenic larch. This novel technique can not only accelerate the generation of superior transgenic strains of L. olgensis but also aid in future gene functional studies.
【目的】以落叶松胚性系为研究对象,建立和优化适合落叶松胚性愈伤组织增殖的悬浮培养体系,在此基础上对悬浮组织进行体细胞胚的成熟诱导。旨在为实现落叶松胚性愈伤组织的快速增殖及体细胞胚的规模化繁育奠定基础。【方法】对已诱导获得的长白落叶松、兴安×日本杂种落叶松及日本×长白杂种落叶松胚性愈伤组织进行继代培养,取新鲜增殖的组织进行悬浮培养。采用L9(34)正交试验设计,以胚性愈伤组织的增殖量及增殖率为响应值对悬浮培养条件进行筛选和优化,并对选出的最适培养条件进行验证。以悬浮增殖的胚性组织进行体细胞胚成熟培养,统计体胚发生量。【结果】在落叶松胚性愈伤组织的悬浮培养过程中,接种量、震荡强度及培养时间对胚性组织增殖具有显著的影响。在一定范围内,落叶松胚性组织的增殖量及增殖率随初始接种量的增加而降低,随震荡强度的升高呈先增加后下降,而随培养周期的延长而增加。以4 g·L -1 接种于含2,4-D 0.15 mg·L -1 、6-BA 0.05 mg·L -1 及KT 0.05 mg·L -1 的BM培养基(SCM),在120 r·min -1 避光条件下悬浮培养,3个落叶松胚性系的胚性组织均能快速、稳定地增殖,培养15天的增殖率分别为2 569.42%、4 189.96%及3 001.67%,表现出较明显的种间差异。成熟培养方式对落叶松胚性悬浮组织的体胚发生量影响极显著(P=0.000)。悬浮培养获得的胚性组织接种到含琼脂6.0g·L -1 的固体增殖培养基(PCM)上继代15天后,转接到添加肌醇10 g·L -1 且无生长调节剂的1/4BM过渡培养基(TCM)上培养14天,再转入含有ABA 20 mg·L -1 、Ag NO35 mg·L -1 、PEG400080 g·L -1 的体胚成熟培养基上培养8周,体胚发生量显著提高(P=0.000)。在此条件下,3个落叶松胚性系OO-A1、GK-F1及KO-H的体胚发生量分别为(101.69±11.19)、(93.09±9.34)及(5.78±1.47)个·g -1 。【结论】悬浮培养能在短期内获得大量分散均匀、质量较高的落叶松胚性愈伤组织,且不会影响体细胞胚的发生和成熟。在BM液体培养基(SCM)中,接种量为4 g·L -1 、震荡强度为120 r·min -1 、暗培养15天,落叶松胚性组织的鲜质量可增加26.99~42.90倍。悬浮培养获得的胚性组织经固体增殖培养基(PCM)继代15天及过渡培养基(TCM)预培养14天后,再进行体胚成熟诱导可明显提高其体胚发生量。