Transgenic Petunia hybrida with Silicon Transporter Protein OsLsi1 and OsLsi2 Genes and Its Drought Resistance Analysis

As one of the important materials in landscaping for flower terrace and border, Petunia hybrida needs high environmental conditions and its growth is seriously influenced by the drought. Silicon is considered to be a necessary element for plant growth, and soluble silicon can improve plant resilience. To improve the drought resilience of Petunia hybrida, the silicon transporter protein OsLsi1 and OsLsi2 genes cloned from rice（Oryza sative） were transferred into Petunia hybrida by Agrobacterium-mediated method, and finally got 26 and 32 positive plants, respectively by PCR and RT-PCR detections. With a control of non-transgenic plants, the obtained transgenic plants were taken by drought treatment stress for 0, 4, 7, 10 and 14 days, then re-watered and measured physiological indexes as malondialdehyde（MDA） content, free proline（Pro） content, superoxide dismutase（SOD） activity and peroxidase（POD） activity to study the effect of Petunia＇s drought resistance. All the results proved that the silicon transporter protein OsLsi1 and OsLsi2 genes were normally transcripted and expressed in transgenic Petunia hybrida; OsLsi1 gene could improve the abilities of plants＇ drought resistance and recover after drought stress, while OsLsi2 gene could reduce the above abilities. The order of the drought resistance ability of the three strains from strong to weak was OsLsi1〉CK〉OsLsi2; and silicon indeed improved the ability of drought resistance as well. All these results provided a new way to improve the drought resistance of Petunia, and laid a foundation to improve the ability of garden plants＇ drought resistance and water saving.

Carrier Transport Across Grain Boundaries in Polycrystalline Silicon Thin Film Transistors

We established a model for investigating polycrystalline silicon（poly-Si） thin film transistors（TFTs）.The effect of grain boundaries（GBs） on the transfer characteristics of TFT was analyzed by considering the number and the width of grain boundaries in the channel region,and the dominant transport mechanism of carrier across grain boundaries was subsequently determined.It is shown that the thermionic emission（TE） is dominant in the subthreshold operating region of TFT regardless of the number and the width of grain boundary.To a poly-Si TFT model with a 1 nm-width grain boundary,in the linear region,thermionic emission is similar to that of tunneling（TU）,however,with increasing grain boundary width and number,tunneling becomes dominant.

Nodulin 26-like intrinsic protein Cs NIP2;2 is a silicon influx transporter in Cucumis sativus L.

Nodulin 26-like intrinsic proteins(NIPs) are a family of channel-forming transmembrane proteins that function in the transport of water and other small molecules.Some NIPs can mediate silicon transport across plasma membranes and lead to silicon accumulation in plants,which is beneficial for the growth and development of plants.Cucumber is one of the most widely consumed vegetables;however,the functions of NIPs in this crop are still largely unknown.Here,we report the functional characteristics of Cs NIP2;2.It was found that Cs NIP2;2 is a tandem repeat of Cs NIP2;1,which had been demonstrated to be a silicon influx transporter gene.Cs NIP2;2 has a selectivity filter composed of cysteine,serine,glycine and arginine(CSGR),which is different from all previously characterized silicon influx transporters in higher plants at the second helix position.Xenopus laevis oocytes injected with Cs NIP2;2 c RNA demonstrated a higher uptake of silicon than the control,and the uptake remained unchanged under low temperature.Cs NIP2;2 was found to be expressed in the root,stem,lamina and petiole,and exogenous silicon treatment decreased its expression in the stem but not in other tissues.Transient expression of Cs NIP2;2-e GFP fusion sequence in onion epidermal cells showed that Cs NIP2;2 was localized to the cell nucleus,plasma membrane and an unknown structure inside the cell.The results suggest that Cs NIP2;2 is a silicon influx transporter in cucumber,and its subcellular localization and the selectivity filter are different from those of the previously characterized silicon influx transporters in other plants.These findings may be helpful for understanding the functions of NIPs in cucumber plants.

Enhanced Current Transportation in Siliconriched Nitride(SRN)/Silicon-riched Oxide(SRO)Multilayer Nanostructure

A novel structure of silicon-riched nitride(SRN)/silicon-riched oxide(SRO) is proposed and prepared using RF reactive magnetron co-sputtering. High temperature annealing of SRN/SRO multilayers leads to formation of Si nanocrystals(NC) from isolating SRN and SRO layers simultaneously, which efficiently improves carrier transport ability compared to conventional SRN/Si_3N_4 counterpart. Micro-Raman scattering analysis reveals that SRN layer has dominating number of denser and smaller Si NCs, while SRO layer has relatively less, sparser and bigger Si NCs, as confirmed by high resolution transmission electron microscopy observation. The substitute SRO layers for Si_3N_4 counterparts significantly increase the amount of Si NCs as well as crystallization ratio in SRN layers; while the average Si NC size can be well controlled by the thickness of SRN layers and the content of N, and hence an obvious stronger absorption in UV region for the novel structure can be observed in absorption spectra. The I-V characteristics show that the current of hybrid SRN/SRO system increases up to 2 orders of magnitude at 1 V and even 5 orders of magnitude at 4 V compared to that of SRN/Si_3N_4 structure. Si NCs in Si Oylayers provide a transport pathway for adjacent Si NCs in Si Nxlayers. The obvious advantage in carrier transportation suggests that SRN/SRO hybrid system could be a promising structure and platform to build Si nanostructured solar cells.

Effects of thermal transport properties on temperature distribution within silicon wafer

A combined conduction and radiation heat transfer model was used to simulate the heat transfer within wafer and investigate the effect of thermal transport properties on temperature non-uniformity within wafer surface. It is found that the increased conductivities in both doped and undoped regions help reduce the temperature difference across the wafer surface. However, the doped layer conductivity has little effect on the overall temperature distribution and difference. The temperature level and difference on the top surface drop suddenly when absorption coefficient changes from 104 to 103 m-1. When the absorption coefficient is less or equal to 103 m-1, the temperature level and difference do not change much. The emissivity has the dominant effect on the top surface temperature level and difference. Higher surface emissivity can easily increase the temperature level of the wafer surface. After using the improved property data, the overall temperature level reduces by about 200 K from the basis case. The results will help improve the current understanding of the energy transport in the rapid thermal processing and the wafer temperature monitor and control level.

Study on Thermal Transport Coefficient of Electron in the Siliconized HT-7 Tokamak

Siliconization is a normal method for the first-wall conditioning on the HT-7 toka-mak. After siliconization the total radiation loss is reduced significantly. Heat-diffusion coefficient the electron of is reduced obviously at the outer half radius (r/a > 0.5) after siliconization. And the plasma confinement is improved effectively. At the core of the plasma, electromagnetic drift-wave mode driven by the temperature gradient of electron gives a good representation of the experimental data not only before siliconization but also after siliconization. But at the outer half radius, the Parail's electromagnetic drift-wave even mode gives a good description of the experimental data before siliconization, and the experimental data of Xe is close to the collisionless electrostatic drift-wave mode turbulence after siliconization.

富硅或富磷育秧降低水稻砷含量的效果及其分子机制

砷(As)主要通过硅和磷通道进入水稻根系,合理的硅和磷施用方式可有效调控水稻对As的吸收转运。研究通过在水稻育秧阶段进行硅或磷富集,探讨富硅或富磷秧苗移栽至As污染土壤后对糙米As含量的影响及分子机制。试验结果表明,富硅或富磷育秧在不影响生长的前提下,可使秧苗的硅或磷整株吸收量分别增至对照的19.6和2.3倍。与常规育秧相比,富硅育秧处理糙米中总砷、三价砷、五价砷以及二甲基砷含量分别降低31.1%、32.1%、58.3%、33.5%。富磷育秧对糙米总砷含量没有显著影响,但使糙米五价砷含量降低59.2%。富硅或富磷育秧可显著增加As在水稻根系中的滞留且不同程度影响As在水稻各部位之间的转移系数。根系As转运基因相对表达量的分析结果表明,与对照相比,富硅育秧对OsLsi1的相对表达量没有显著影响,使OsLsi2的相对表达量下调26%,OsABCC1的相对表达量上调203%;富磷育秧对OsPT1的相对表达量没有显著影响,使OsPT4以及OsPT8的相对表达量分别下降51%和71%,OsABCC1的相对表达量上调22%。综上,富硅或富磷育秧可通过调控水稻根系As相关转运基因的表达来影响水稻对As的吸收及转运,从而降低糙米As含量。研究结果可为稻田As污染风险管控提供重要参考。

植物硅转运蛋白研究进展

硅作为一种非金属元素,不仅在植物的生长发育过程中发挥重要的功能,同时在植物抵御生物和非生物胁迫中也发挥着重要的作用。研究表明硅的吸收与转运由硅转运蛋白参与完成,根据对硅酸的转运特性主要分为硅内流转运蛋白和硅外流转运蛋白。该文对已鉴定出的硅转运蛋白的结构特点、功能、调控方式进行了总结,对植物吸收与转运硅的过程进行了系统性解析,提出了存在的问题,并对未来的研究方向进行了展望。

Reduction and Reoxidation of Silicon in Blast Furnace Hearth

This paper introduces both laboratory experi- ment and equilibrium calculations concerned with the Si reduction and reoxidation.The results give evidence that the Si transport in different directions just exists in the furnace hearth synchronistically, by which the desulphurization is also affected.The problems noticed for smelting tow Si pig iron are given.

MFI纳米片沉积层气相转化制备超薄b轴取向沸石膜

利用乙二胺-水蒸汽进行气相转化(VPT)制备超薄、取向MFI沸石膜,通过将MFI纳米片沉积层转化为致密的沸石膜,实现了膜厚度的有效控制。扫描电子显微镜和X射线衍射表明,制备的沸石膜膜厚度约为280 nm,具有高度b轴取向的致密结构。丁烷异构体双组分分离测试结果表明,在333 K下,等物质的量的正丁烷/异丁烷混合物的正丁烷渗透速率和分离因子分别为1.5×10^(-7)mol·m^(-2)·s^(-1)·Pa^(-1)和14.8。Na_(2)Si O_(3)作为低聚硅源在MFI沸石纳米片二次生长过程中能够提供硅源和碱度,通过在胺类蒸汽中实现MFI沸石纳米片间的融合生长,进一步提高了膜的取向度和致密性。

基于炭/炭复合材料加工余料制备碳化硅粉末的组织及性能

以炭/炭复合材料加工余料为碳源,与硅粉充分混合,通过高温合成法制备单晶生长用碳化硅粉末,并对其显微组织和表面性能进行研究。结果表明:制备出的碳化硅粉末晶型为β-SiC,部分继承了炭/炭复合材料加工余料的管槽状、脊状结构。在拉曼光谱中,该粉末的折叠横光与折叠纵光的半峰全宽之比为0.709,其相对纯度高于以石墨粉为碳源同工艺制备的碳化硅粉末。该碳化硅粉末具有多孔特征,比表面积为25.7426 m^(2)/g,可用于物理气相传输单晶生长工艺,且已初步验证其可行性。

基于8英寸的碳化硅单晶生长炉技术

碳化硅是制作高温、高频、大功率以及高压器件的理想材料之一。为提高生产效率并降低成本,大尺寸碳化硅衬底的制备是重要发展方向。针对8英寸碳化硅单晶生长的工艺需求,分析了碳化硅物理气相输运法生长机理,研究了碳化硅单晶生长炉的加热系统、坩埚旋转、工艺参数控制技术,通过热场模拟仿真分析和工艺试验,成功制备生长了8英寸晶体。

Silicon acquisition and accumulation in plant and its significance for agriculture

Although silicon（Si） is ubiquitous in soil and plant, evidence is still lacking that Si is essential for higher plants. However, it has been well documented that Si is beneficial for healthy growth of many plant species. Si can promote plant mechanical strength, light interception, as well as resistance to various forms of abiotic and biotic stress, thus improving both yield and quality. Indeed, application of Si fertilizer is a rather common agricultural practice in many countries and regions. As the beneficial effects provided by Si are closely correlated with Si accumulation level in plant, elucidating the possible mechanisms of Si uptake and transport in plants is extremely important to utilize the Si-induced beneficial effects in plants. Recently, rapid progress has been made in unveiling molecular mechanisms of Si uptake and transport in plants. Based on the cooperation of Si influx channels and efflux transporters, a model to decipher Si uptake, transport and distribution system in higher plants has been developed, which involves uptake and radial transport in root, xylem and inter-vascular transport and xylem unloading and deposition in leaf. In this paper, we overviewed the updated knowledge concerning Si uptake, transport and accumulation and its significance for the major crops of agricultural importance and highlighted the further research needs as well.

基于金刚线切片的钙钛矿/硅叠层太阳电池

提出一种免空穴传输层的策略,将自组装单分子层材料作为钙钛矿活性层的添加剂,通过一步旋涂法直接将钙钛矿薄膜制备在导电基底表面,其中薄膜的质量与均一性都得到改善。进一步地,将该方法应用在低成本的商用金刚线切片上,可在高粗糙度的硅表面制备出覆盖度高、形貌致密、无空洞的钙钛矿薄膜。在光电性能方面,用该方法得到的单结钙钛矿太阳电池的光电转换效率为21%,填充因子高达83%,两端钙钛矿/硅叠层太阳电池的光电转换效率为28%。

Versatile Potentiality of Silicon in Mitigation of Biotic and Abiotic Stresses in Plants: A Review

The “quasi-essential element” silicon (Si) is not considered indispensable for plant growth and its accumulation varies between species largely due to differential uptake phenomena. Silicon uptake and distribution is a complex process involving the participation of three transporters (Lsi1, Lsi2 and Lsi6) and is beneficial during recovery from multiple stresses. This review focuses on the pivotal role of silicon in counteracting several biotic and abiotic stresses including nutrient imbalances, physical stresses together with uptake, transport of this metalloid in a wide variety of dicot and monocot species. The knowledge on the beneficial effects of silicon and possible Si-induced mechanisms of minimizing stress has been discussed. Accumulation of silicon beneath the cuticles fortifies the cell wall against pathogen attack. Si-induced reduction of heavy metal uptake, root-shoot translocation, chelation, complexation, upregulation of antioxidative defense responses and regulation of gene expression are the mechanisms involved in alleviation of heavy metal toxicity in plants. Silicon further improves growth and physiological attributes under salt and drought stress. Effective use of silicon in agronomy can be an alternative to the prevalent practice of traditional fertilizers for maintaining sustainable productivity. Therefore, soil nutrition with fertilizers containing plant-available silicon may be considered a cost-effective way to shield plant from various stresses, improve plant growth as well as yield and attain sustainable cultivation worldwide.

Thermoelastic stresses in SiC single crystals grown by the physical yapor transport method

A finite element-based thermoelastic anisotropic stress model for hexagonal silicon carbide polytype is developed for the calculation of thermal stresses in SiC crystals grown by the physical vapor transport method. The composite structure of the growing SiC crystal and graphite lid is considered in the model. The thermal expansion match between the crucible lid and SiC crystal is studied for the first time. The influence of thermal stress on the dislocation density and crystal quality is discussed.

Forward and reverse electron transport properties across a CdS/Si multi-interface nanoheterojunction

The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporous pillar array, an untraditional, nonplanar, and multi-interface CdS/Si nanoheterojunction is prepared. The current density versus voltage curve is measured and an obvious rectification effect is observed. Based on the fitting results and model analyses on the forward and reverse conduction characteristics, the electron transport mechanism under low forward bias, high forward bias, and reverse bias are attributed to the Ohmic regime, space-charge-limited current regime, and modified Poole-Frenkel regime respectively. The forward and reverse electrical behaviors are found to be highly related to the distribution of inter- facial trap states and the existence of localized electric field respectively. These results might be helpful for optimizing the preparing procedures to realize high-performance silicon-based CdS optoelectronic devices.

硅基叶面阻控剂对水稻的控镉效应

在中轻度Cd污染区域开展大田试验,探索不同用量的硅基叶面阻控剂对土壤有效Cd、水稻(Oryza sativa L.)不同器官Cd含量及Cd转运的影响。结果表明,叶面阻控剂不能降低土壤有效Cd含量,但能调控Cd在水稻器官中的转运与富集,与不施叶面阻控剂对照相比,水稻根、茎、叶与稻米中Cd含量分别降低13.06%~27.03%、17.39%~36.96%、14.89%~42.55%、11.11%~32.83%,水稻对Cd的富集从高到低依次为根、茎、叶、稻米。水稻植株中Cd从根到茎(TF根-茎)、茎到叶(TF茎-叶)、叶到稻米(TF叶-稻米)的转运系数分别为0.36~0.42、0.47~0.53、0.42~0.50,其中根到茎的转运系数最低,且随叶面阻控剂用量的增加其转运系数逐渐降低。施用一定量的叶面阻控剂在一定程度上能提高水稻产量,从经济成本和降镉效果等因素综合考虑,用量为4 500 mL/hm~2时,成本低廉且效果较佳。

Oxygen Incorporation in Czochralski Growth of Silicon under a Horizontal Magnetic Field

A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field (HMCZ) is proposed. Oxygen depleted surface melt, driven to the growth interface by the thermal Marangoni flow, determines oxygen concentration in the grown crystals. Systematic study was carried out to investigate effects of growth parameters on oxygen incorporation into crystals.

水稻颖壳类病斑突变体glmm1的鉴定与基因定位

【目的】鉴定水稻颖壳类病斑突变体,并进行基因定位,为基因克隆及其分子机制研究奠定基础。【方法】对野生型材料LR005和经EMS诱变得到的颖壳类病斑突变体glmm1(glume lesion mimics mutant 1)进行农艺性状分析、扫描电镜分析、DAB染色和全硅含量测定。glmm1与广亲和材料L422杂交获得的F2群体用于遗传分析,利用图位克隆和BSA-seq方法进行基因定位。【结果】突变体glmm1在抽穗10 d后颖壳和叶片逐渐出现褐色斑点,成熟后颖壳完全呈现褐色。与野生型相比,突变体的株高、穗长、每穗总粒数、结实率和千粒重等都极显著降低。DAB染色表明glmm1颖壳和叶片的活性氧含量增多;扫描电镜显示突变体颖壳和叶片表面硅质细胞皱缩。遗传分析结果表明,突变体glmm1的颖壳类病斑表型受到一对隐性基因控制。利用glmm1与L422的F2分离群体,通过图位克隆和BSA-seq等策略将glmm1定位在水稻第2染色体上68 kb的区间内。该区间内有10个候选基因。序列分析发现该区间仅有一个SNP位点,位于基因Lsi1(LOC_Os02g51110)的第5个外显子上,导致第238位氨基酸由异亮氨酸变为苏氨酸。对颖壳和叶片全硅含量的测定表明,glmm1突变体中硅的积累减少,说明GLMM1可能是Lsi1的等位突变。【结论】GLMM1是Lsi1新的等位突变基因,该突变造成植株硅含量的降低和活性氧的积累,致使颖壳和叶片产生褐色类病斑。