人类TECTB基因的电子克隆

用小鼠和鸡的β-tectorin基因（Tectb)的编码区序列对NCBI数据库进行Blastn比较,得到一个相似性很高的人的gDNA序列（GenBank:AL157786),用GENSCAN、MZEF程序和Blast 2 sequence程序分析AL157786,推测AL157786中包含一个编码区由10个外显子构成的基因－TECTB基因。人TECTB基因的开放阅读框为990bp,推测编码329个氨基酸。人TECTB基因与小鼠的Tectb基因在900bp有88.1%的一致性,在329个氨基酸有94.2%的一致性。用Electronic-PCR将人TECTB基因定位于10q25。     

HvLsi1 is a silicon influx transporter in barley

Most plants accumulate silicon in their bodies, and this is thought to be important for resistance against biotic and abiotic stresses; however, the molecular mechanisms for Si uptake and accumulation are poorly understood. Here, we describe an Si influx transporter, HvLsi1, in barley. This protein is homologous to rice influx transporter OsLsi1 with 81% identity, and belongs to a Nod26-like major intrinsic protein sub-family of aquaporins. Heterologous expression in both Xenopus laevis oocytes and a rice mutant defective in Si uptake showed that HvLsi1 has transport activity for silicic acid. Expression of HvLsi1 was detected specifically in the basal root, and the expression level was not affected by Si supply. There was a weak correlation between Si uptake and the expression level of HvLsi1 in eight cultivars tested. In the seminal roots, HvLsi1 is localized on the plasma membrane on the distal side of epidermal and cortical cells. HvLsi1 is also located in lateral roots on the plasma membrane of hypodermal cells. These cell-type specificity of localization and expression patterns of HvLsi1 are different from those of OsLsi1. These observations indicate that HvLsi1 is a silicon influx transporter that is involved in radial transport of Si through the epidermal and cortical layers of the basal roots of barley.     

Prospective Life Cycle Assessment of Epitaxial Graphene Production at Different Manufacturing Scales and Maturity

Epitaxial growth is a potential production process for the new material graphene, where it is grown on silicon carbide (SiC) wafers at high temperatures. We provide first estimates of the life cycle cumulative energy demand, climate change, terrestrial acidification, and eco‐toxicity of this production. For this purpose, we applied prospective life cycle assessment (LCA) for three production scenarios (lab, pilot, and an industrial scenario), which reflect different production scales and technological maturity. The functional unit was one square centimeter of graphene. Results show that the three scenarios have similar impacts, which goes against previous studies that have suggested a decrease with larger production scale and technological maturity. The reason for this result is the dominance of electricity use in the SiC wafer production for all impacts (>99% in the worst case, >76% in the best case). Only when assuming thinner SiC wafers in the industrial scenario is there a reduction in impacts by around a factor of 10. A surface‐area–based comparison to the life cycle energy use of graphene produced by chemical vapor deposition showed that epitaxial graphene was considerably more energy intensive—approximately a factor of 1,000. We recommend producers of epitaxial graphene to investigate the feasibility of thinner SiC wafers and use electricity based on wind, solar, or hydropower. The main methodological recommendation from the study is to achieve a temporal robustness of LCA studies of emerging technologies, which includes the consideration of different background systems and differences in production scale and technological maturity.     

Very High Surface Capacity Observed Using Si Negative Electrodes Embedded in Copper Foam as 3D Current Collectors

Cu foam is evaluated as a replacement for metal foil current collectors to create 3D composite electrodes with the objective to produce Si‐based anodes with high loadings. The electrodes are prepared by casting the slurry into the porosity of the foam. With such a design, the loading and the surface capacity can reach values as high as 10 mg cm^?2 and 10 mAh cm^?2. Compared to the common 2D design, the 3D copper framework shows a great advantage in the cycle life (more than 400 cycles at a Si loading of 10 mg cm^?2 with commercial micrometric particles) and power performance. The thinness of the composite coating on the foam walls favors a better preservation of the electronic wiring upon cycling and fast lithium ion diffusion. A higher coulombic efficiency in half cells with lithium metal as the counter electrode is achieved by using carbon nanofibers (CNF) rather than carbon black (CB). The possibility to reach, in practice, higher surface capacity could allow a significant increase in both the volumetric and gravimetric energy densities by 23% and 19%, respectively, for the Cu foam‐silicon//LiFePO₄ stack compared to the graphite/LiFePO₄ stack of traditional design.     

Uptake and Toxicity of Arsenic,Copper, and Silicon in Azolla caroliniana and Lemna minor

Here we report on the analysis of two aquatic plant species, Azolla caroliniana and Lemna minor, with respect to tolerance and uptake of co-occurring arsenic, copper, and silicon for use in engineered wetlands. Plants were cultured in nutrient solution that was amended with arsenic (0 or 20 μM), copper (2 or 78 μM), and silicon (0 or 1.8 mM) either singly or in combination. We hypothesized that arsenic and copper would negatively affect the uptake of metals, growth, and pigmentation and that silicon would mitigate those stresses. Tolerance was assessed by measuring growth of biomass and concentrations of chlorophyll and anthocyanins. Both plant species accumulated arsenic, copper, and silicon; L. minor generally had higher levels on a per biomass basis. Arsenic negatively impacted A. caroliniana, causing a 30% decrease in biomass production and an increase in the concentration of anthocyanin. Copper negatively impacted L. minor, causing a 60% decrease in biomass production and a 45% decrease in chlorophyll content. Silicon augmented the impact of arsenic on biomass production in A. caroliniana but mitigated the effect of copper on L. minor. Our results suggest that mixtures of plant species may be needed to maximize uptake of multiple contaminants in engineered wetlands.     

施硅提高水稻叶片对紫外线胁迫的抗性

采用加硅与缺硅营养液培养的方法,首次研究证明硅能提高水稻(Oryza sativa L.)叶片抗紫外线胁迫的能力.结果表明,在紫外胁迫条件下,缺硅水稻叶片表面出现明显的棕色伤害斑点,而加硅叶片未出现伤害症状.硅在水稻表皮细胞壁及细胞内部的积累明显促进了紫外吸收物质在表皮细胞中的聚集,使表皮中可溶性酚类物质含量提高17%,不溶性紫外吸收物质的含量增加65%左右.荧光显微镜观察表明,在表皮细胞外壁或胞内沉积的水合二氧化硅固体中包含着大量不溶性的酚类化合物,它们与可溶性酚类物质一起在叶片的上、下表皮细胞中形成了吸收紫外线的屏障.     

盐度对互花米草枯落物分解释放硅、碳、氮元素的影响

为了研究潮汐湿地盐度对枯落物分解过程中硅、碳、氮元素释放的影响,通过室内模拟不同盐度(0、5、15和30)对互花米草枯落物茎和叶分解释放过程中硅、碳、氮元素的动态变化进行测定。结果表明:(1)互花米草茎和叶枯落物失重率和分解速率均随盐度增加而降低。(2)互花米草茎和叶枯落物分解水体中硅含量均随着盐度升高而增加,并且盐度30处理下,枯落物分解硅释放量显著高于盐度0和5(P0.05)。而分解末期生物硅残留量则随盐度升高而降低。(3)不同盐度处理茎枯落物分解碳释放量无显著差异,但叶枯落物分解碳释放量在盐度5、15和30处理中显著高于淡水(P0.05)。(4)互花米草茎枯落物分解释放到水中的NH_4~+-N含量随着盐度的升高而减少,NO_3~--N含量与之相反。研究单因素盐度对枯落物分解及元素释放的影响,可以为预测潮汐湿地枯落物分解对盐水入侵的响应机制提供参考,为湿地生源要素生物地球化学循环过程研究提供基础依据。     

硅介导的水稻对二化螟幼虫钻蛀行为的影响

采用对二化螟敏感(汕优63)和中抗(盐丰47)的水稻品种,设置硅酸钙处理,观察二化螟蚁螟和三龄幼虫在不同处理稻茎上的钻蛀率、蛀入率和蛀入耗时,同时测定不同处理植株的硅细胞数量及植株与土壤的二氧化硅含量,旨在明确水稻施用硅肥对二化螟幼虫钻蛀行为的影响以及这种影响在不同龄期幼虫和不同抗虫性水稻品种间是否存在差异。蚁螟和三龄幼虫钻蛀率随硅肥施用量增加而降低(幅度为5%—28%)。蚁螟蛀入率在硅肥处理之间和水稻品种之间均没有差异;三龄幼虫蛀入率随硅肥施用量增加而显著下降10%—40%,盐丰47上的蛀入率显著低于汕优63(差异10%—30%)。蚁螟蛀入耗时随硅肥施用量增加而显著延长,三龄幼虫蛀入耗时与品种抗性有显著关系。稻茎硅含量随硅肥施用量增加而增大,并且与三龄幼虫蛀入率呈负相关、与三龄幼虫蛀入耗时呈正相关关系。因此,施用硅肥可直接抑制二化螟幼虫钻蛀,蛀入耗时的延长可间接地延长幼虫暴力于其它防治措施的时间;施用硅肥对三龄幼虫成功蛀入的影响大于对蚁螟的影响;相对于抗虫品种,施用硅肥能在更大程度上增强感虫品种对二化螟幼虫钻蛀行为的抑制作用。     

臭氧胁迫下硅对大豆抗氧化系统、生物量及产量的影响

在全球变化情景下,臭氧污染对作物产量将造成严重影响,臭氧将成为未来农业重要胁迫因素。研究缓解臭氧胁迫技术措施有利于保障粮食安全,其中硅元素添加可能是有效途径之一。利用开顶式同化箱(open top chambers,OTCs)装置,设置两个O3浓度(大气O3浓度<40μg/kg和高O3浓度约为80μg/kg)、两个硅浓度(0和100μg/g),研究不同O3浓度下硅对开花后大豆(Glycine max)株高、叶面积、叶绿素含量、抗氧化系统及产量的影响。结果表明:在无臭氧胁迫下,施硅可显著提高大豆根生物量、总生物量和单株籽粒重(14%、5%和20%)(P<0.05)。在O3胁迫下,施硅能使大豆维持较高的叶面积,显著提高大豆叶片叶绿素含量及SOD、POD、CAT活性,显著降低MDA含量,提高大豆根生物量、地上部生物量、总生物量、根冠比和单株籽粒重(29%,18%,19%,9%和17%)(P<0.05)。研究可为缓解O3对大豆危害提供合理可行的栽培管理措施与理论依据。     

低温胁迫下乌塌菜对外源硅的生理响应

在土培条件下,研究了低温胁迫下不同浓度的硅酸钠对乌塌菜幼苗生长及生理特性的影响。结果表明,低温胁迫抑制了乌塌菜的生长,降低了干物质的积累。外施硅可以显著提高乌塌菜叶片SOD、POD、CAT活性,迅速积累大量的脯氨酸和可溶性蛋白,从而有效缓解低温胁迫对乌塌菜幼苗的影响,尤其是外施0.5mmol·L^-1Na2SiO3处理15d时,乌塌菜干物质积累达到了正常生长植株的86.2%。但随着施用硅浓度的增加,缓解效果则降低。