目的水稻产量由单位面积有效穗数、每穗粒数和粒重3个因素构成,其中,粒重主要由水稻的籽粒形态决定.筛选和鉴定新的粒型突变材料和基因,可为产量性状的分子设计育种奠定基础.方法在籼稻保持系西大1B(XD1B)的甲基磺酸乙酯(EMS)诱变群体中鉴定到一个短宽粒突变体short and widen grain ...1(swg1);分析籽粒形态和其他农艺性状,并对颖壳进行组织细胞学观察分析;运用BSA法进行基因定位;通过遗传互补试验确定候选基因;采用qRT-PCR分析该基因的表达模式及其他粒型相关基因和细胞发育基因的表达水平.结果农艺性状分析发现,与野生型相比,swg1突变体粒长显著降低,粒宽显著增加,表现出短宽粒的表型;进一步组织和细胞学分析,发现突变体颖壳纵向细胞变短是粒长变短的主要原因,而粒宽增加是由于颖壳横向细胞数目和细胞大小同时增加.遗传分析结果表明,该突变性状受隐性单基因控制,通过图位克隆与遗传互补验证,确定候选基因为LOC-Os07g42410,编码一个植物特异转录因子.qRT-PCR分析发现该基因表达无明显的组织特异性,在茎、叶、幼穗中表达强烈.通过对已知粒型相关基因、细胞周期和细胞扩展相关基因进行分析,发现通过正向调控颖壳横向细胞数目和(或)细胞大小决定粒宽的GS5和GW8在突变体中上调明显,而正向调控纵向细胞数目和大小并负向调控横向细胞数目和大小的GW7/GL7在突变体明显下调;另外,部分与细胞周期和细胞扩展相关的基因也在突变体和野生型之间的表达也呈现显著差异.结论SWG1编码一个植物特异的转录因子,通过调控粒型基因(GS5、GW8和GW7/GL7等)影响颖壳的细胞增殖和细胞扩展,从而决定水稻籽粒长度和宽度.
On the basis of upper bound theorem, non-associated flow rule and non-linear failure criterion were considered together. The modified shear strength parameters of materials were obtained with the ...help of the tangent method. Employing the virtual power principle and strength reduction technique, the effects of dilatancy of materials, non-linear failure criterion, pore water pressure, surface loads and buried depth, on the stability of shallow tunnel were studied. In order to validate the effectiveness of the proposed approach, the solutions in the present work agree well with the existing results when the non-associated flow rule is reduced to the associated flow rule and the non-linear failure criterion is degenerated to the linear failure criterion. Compared with dilatancy of materials, the non-linear failure criterion exerts greater impact on the stability of shallow tunnels. The safety factor of shallow tunnels decreases and the failure surface expands outward when the dilatancy coefficient decreases. While the increase of nonlinear coefficient, the pore water pressure coefficient, the surface load and the buried depth results in the small safety factor. Therefore, the dilatancy as well as non-linear failure criterion should be taken into account in the design of shallow tunnel supporting structure. The supporting structure must be reinforced promptly to prevent potential mud from gushing or collapse accident in the areas with abundant pore water, large surface load or buried depth.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Polycrystalline Ge1-xSnx（poly-Ge1-xSnx） alloy thin films with high Sn content（〉 10%） were fabricated by cosputtering amorphous GeSna-GeSn on Ge100 wafers and subsequently pulsed laser annealing with ...laser energy density in the range of 250 mJ/cm^2 to 550 mJ/cm^2. High quality poly-crystal Ge0.90 Sn0.10 and Ge0.82 Sn0.18 films with average grain sizes of 94 nm and 54 nm were obtained, respectively. Sn segregation at the grain boundaries makes Sn content in the poly-GeSn alloys slightly less than that in the corresponding primary a-GeSn. The crystalline grain size is reduced with the increase of the laser energy density or higher Sn content in the primary a-GeSn films due to the booming of nucleation numbers. The Raman peak shift of Ge-Ge mode in the poly crystalline GeSn can be attributed to Sn substitution, strain,and disorder. The dependence of Raman peak shift of the Ge-Ge mode caused by strain and disorder in GeSn films on full-width at half-maximum（FWHM） is well quantified by a linear relationship, which provides an effective method to evaluate the quality of poly-Ge1-xSnx by Raman spectra.
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