The seed dormancy characteristic is regarded as one of the most critical factors for pre-harvest sprouting (PHS) resistance. As a wild wheat relative species, Aegilops tauschii is a potential genetic resource for improving common wheat. In this study, an advanced backcross population (201 strains) containing only Ae. tauschii segments was developed by means of synthetic octaploid wheat (hexaploid wheat Zhoumai 18 × Ae. tauschii T093). Subsequently, seed dormancy rate (Dor) in the advanced backcross population was evaluated on the day 3, 5 and 7, in which 2 major QTLs (QDor-2D and QDor-3D) were observed on chromosomes 2D and 3D with phenotypic variance explained values (PVEs) of 10.25 and 20.40%, respectively. Further investigation revealed significant correlation between QDor-3D and Tamyb10 gene, while no association was found between the former and TaVp1 gene, implying that QDor-3D site could be of closer position to Tamyb10. The obtained quantitative trait locus sites (QTLs) in this work could be applied to develop wheat cultivars with PHS resistance.
Wheat pre-harvest sprouting (PHS) causes serious losses in wheat yield. In this study, precise mapping was carried out in the chromosome segment substitution lines (CSSL) F2 population generated by a direct cross of Zhoumai 18 (PHS-sensitive) and Aegilops tauschii accession T093 (highly PHS-resistant). Three Ae. tauschii-derived quantitative trait loci (QTLs), QDor.3D.1, QDor.3D.2, and QDor.3D.3, were detected on chromosome 3DL using four simple sequence repeats (SSR) markers and 10 developed Kompetitive allele-specific PCR (KASP) markers. Alongside these QTL results, the RNA-Seq and qRT-PCR analysis revealed expression levels of TraesCS3D01G466100 in the QDor.3D.2 region that were significantly higher in CSSLs 495 than in Zhoumai 18 during the seed imbibition treatment. The cDNA sequencing results of TraesCS3D01G466100 showed two single nucleotide polymorphisms (SNPs), resulting in two changed amino acid substitutions between Zhoumai 18 and line 495, and the 148 nt amino acid substitution of TraesCS3D01G466100, derived from Ae. tauschii T093, which may play an important role in the functioning of ubiquitin ligase enzymes 3 (E3) according to the homology protein analysis, which could lead to differential PHS-resistance phenotypes. Taken together, our results may foster a better understanding of the mechanism of PHS resistance and are potentially valuable for marker-assisted selection in practical wheat breeding efforts.
Spontaneous imbibition of hydraulic
fracturing fluids into the
water-wet inorganic media is a ubiquitous phenomenon, which has an
important influence on tight/shale oil recovery and groundwater contamination.
However, in nanoscale space, the fluid–solid (water–wall
and oil-wall) molecular interactions, which can result in the nanoscale
effects of the slip boundary and the varying interfacial fluid viscosity,
will make the fluid flow behaviors be more complex and difficult to
characterize. In this work, a new generalized imbibition model in
inorganic nanopores and porous media is established by the theoretical
analysis and a nanoscale Shan–Chen lattice Boltzmann method
(LBM). The effects of pore dimensions and shapes in porous media,
the nanoscale effects, the dynamic contact angle, and the entrance
effect are considered and discussed. The results show that the proposed
model can accurately characterize the oil/water imbibition mechanisms
and be adapted to different nanoscale effects. Based on discussions,
this study can provide microscopic basics of water imbibing into nanopores
and provide guiding information and theoretical model for the oil
recovery from tight/shale reservoirs by hydraulic fracturing, the
groundwater remediation by restricting imbibition rate, and other
relevant applications.
The aim of this paper is to present both experimental and theoretical investigations on nanofluid flow with dynamic adsorption, detachment and straining behavior, and its associated formation damage. In this paper, we conduct core-flooding experiments on oil-wet Berea sandstone. Hydrophilic Nano-structure particles (NSP) is dispersed in the injected brine stream at 0.05, 0.2 and 0.5wt% concentrations. During the core-flooding of nanoparticles injection and post-flush of brine, the corresponding pressure drops across the cores and the effluent nanoparticles concentration are recorded. In order to quantify nanoparticles adsorption/detachment and straining behavior and associated effects on fluid flow, an analytical model is derived using method of characteristics. The interplay between nanoparticles and rocks is described by the coupled the classical particles filtration theory and maximum adsorption concentration model. All the necessary parameters, i.e., the maximum adsorption concentration, reversible or detachment adsorption concentration, nanoparticles adsorption and straining rates, and the corresponding formation damage coefficients, are characterized by matching analytical solutions with the effluent nanoparticles concentration history and real-time pressure drop.
The experimental results indicated that both adsorption and straining occur during the injection. The extent of adsorption and straining for Nano-structure particles (NSP), i.e., maximum adsorption concentration, particles adsorption rate and straining rates, increases along with the increase of nanoparticles injection concentration. As the results, the breakthrough time of nanoparticles injection is delayed, the steady-state effluent concentration decreases, and the pressure drop increases more rapidly. The adsorption amount of nanoparticles includes the reversible and irreversible adsorption. During the post-flush of brine, the reversible adsorbed nanoparticles detach from the already adsorption layers. With the increase of nanoparticle injection concentration, the reversible or detachment of adsorbed nanoparticles also increase.
In practice, this paper will contribute for the following applications 1) apply lab experiments to highlight the importance of nanoparticles adsorption, straining and detachment behaviors on the formation damage. 2) The analytical solution provides physical insights to quantify nanofluid flow performance, and can also be used to optimize the usuage of nanofluids application while considering the loss caused nanoparticles adsorption and straining.
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