冀西北坝上地区大蒜播种期研究

为了探讨冀西北坝上地区大蒜适宜的播种期,给当地大蒜高效生产提供理论依据,试验以大蒜品种西八里为试验材料,设置A(3月22日)、B(4月1日)、C(4月11日)3个不同播期,测定了不同播期下大蒜的生育期、植株性状、蒜头性状、蒜薹和蒜头产量等指标。结果表明,播期B和C较播期A的出苗时间分别缩短7 d和11 d;播期B的植株性状、蒜头性状均优于播期A和C,播期B一级蒜的比例最高,较播期A、C分别高出11.0和27.6个百分点;播期B较播期A和C的蒜薹产量分别提高8.41%和40.82%,蒜头产量分别提高10.19%和16.08%。本试验条件下,坝上地区大蒜适宜的播种期为3月底至清明节之间。     

Thermal Structure of Jupiter's Upper Atmosphere Derived from the Galileo Probe

Temperatures in Jupiter's atmosphere derived from Galileo Probe deceleration data increase from 109 kelvin at the 175-millibar level to 900 ± 40 kelvin at 1 nanobar, consistent with Voyager remote sensing data. Wavelike oscillations are present at all levels. Vertical wavelengths are 10 to 25 kilometers in the deep isothermal layer, which extends from 12 to 0.003 millibars. Above the 0.003-millibar level, only 90- to 270- kilometer vertical wavelengths survive, suggesting dissipation of wave energy as the probable source of upper atmosphere heating.     

秦川牛 MYH8基因多态性及其与生长性状的关联分析

为研究秦川牛MYH8基因的多态性及其与秦川牛生长性状的关联性,选取163头健康的30月±2月龄秦川牛,采用DNA测序技术发现MYH8基因外显子上的SNP位点,并以PCR-RFLP技术分析秦川牛群MYH8基因型,研究其遗传多样性,再通过SPSS 19.0软件分析SNP位点与秦川牛体尺性状和胴体性状的关联性。研究结果表明,在MYH8基因第33外显子上存在3个SNP位点,分别在基因序列26 064、26 094和26 100bp 3处,且26 064bp处(TC)为同义突变,26 094bp处(TC)为错义突变,26 100bp处(CG)为错义突变。关联分析显示,C26100G突变发生在体斜长指标,表现为GG基因型个体的群体均值显著高于GC、CC基因型个体(P0.05);而其他突变中不存在显著性差异。某些基因型(T26064C突变处TC基因型和T26094C突变处CT基因型)可能为优势基因型,但还需通过更多个体验证。说明:MYH8基因对秦川肉牛生长性状存在一定影响。     

Three-dimensional simulations of plume-lithosphere interaction at the hawaiian swell

Rapid lithospheric thinning by mantle plumes has not been achieved in numerical experiments performed to date. Efficient thinning depends on small-scale instabilities that convectively remove lithospheric material. These instabilities are favored by hotter plumes or stronger temperature dependence of viscosity, and a simple scaling independent of rheology controls their onset. This scaling allows extrapolation of the results of numerical experiments to the Earth's mantle. Mantle plumes between 100 and 150 kelvins hotter than the background mantle should exhibit small-scale convective rolls aligned with the plate motion. The unusual variation in heat flow across the Hawaiian swell may be due to such instabilities. It was found that the spreading of the plume creates a downwelling curtain of material that isolates it from the rest of the mantle for distances of at least 1000 kilometers from the plume origin. This isolation has important consequences for the geochemical heterogeneity of the lithosphere and upper mantle.     

Scanning Single-Electron Transistor Microscopy: Imaging Individual Charges

A single-electron transistor scanning electrometer (SETSE)-a scanned probe microscope capable of mapping static electric fields and charges with 100-nanometer spatial resolution and a charge sensitivity of a small fraction of an electron-has been developed. The active sensing element of the SETSE, a single-electron transistor fabricated at the end of a sharp glass tip, is scanned in close proximity across the sample surface. Images of the surface electric fields of a GaAs/AlxGa1-xAs heterostructure sample show individual photo-ionized charge sites and fluctuations in the dopant and surface-charge distribution on a length scale of 100 nanometers. The SETSE has been used to image and measure depleted regions, local capacitance, band bending, and contact potentials at submicrometer length scales on the surface of this semiconductor sample.     

甘蓝型油菜开花期的QTL定位及候选基因鉴定

为了解析油菜开花期性状的遗传机制,利用KN DH群体在冬性、半冬性和春性环境的开花期表型和KN 高密度遗传连锁图谱,通过Wincart 2.5软件的符合区间作图法对油菜开花期性状进行QTL定位及候选基因鉴定。结果显示,共鉴定到119个开花期QTL,单个QTL解释表型变异最大是qFT-13DL16-4 （25.96%）,最小的是qFT-13ZY2-1（2.48%）。利用元分析的方法将初步鉴定的QTL整合为consensus QTL,共获得26个环境稳定表达QTL,包括7个开花期主效QTL。如cqFT-A2-3、cqFT-A2-4在春性环境稳定表达,cqFT-C6-4、cqFT-C6-7、cqFT-C6-12、cqFT-C6-13在冬性和半冬性环境稳定表达, cqFT-C6-14在冬性环境稳定表达QTL。主效QTL置信区间共鉴定到15个与成花诱导相关的候选基因,如 BnaA02g12260D（RGA1）、 BnaA02g15390D（AGL12）、 BnaA02g16710D（LKP2）和BnaC06g19930D（NUA）等,这些候选基因主要涉及赤霉素、光周期、生物钟、春化作用响应和花发育等功能。可见,油菜开花期主效QTL及其候选基因的鉴定为开花期基因的精细定位和图位克隆奠定基础,也为培育早熟、高产油菜品种提供指导。     

小粒野生稻酵母双杂交cDNA文库的构建

采用酵母双杂交系统,利用SMART技术,在酵母菌株AH109中构建了小粒野生稻全长cDNA文库,文库容量约为1×106,插入片段平均大小约为640bp。该文库可以用于进一步的酵母双杂交筛选。     

甘蓝型油菜DH系主要性状及SSR分子标记分析

对173份甘蓝型油菜DH系材料主要农艺性状、品质性状以及SSR分子标记的分析表明,DH系系内性状表现高度一致。农艺性状中,分枝高度的变异系数最大（26.39%）,株高的变异系数最小（9.42%）;品质性状中,芥酸含量变异系数最大（62.86%）,含油量的变异系数最小（5.10%）。SSR分子标记分析发现,DNA谱带符合1∶1分离规律。     

Differential Drought Responses of Faba Bean (Vicia faba L.) Inbred Lines

Drought responses of 19 inbred faba bean lines of different origin were studied in the field under rain shelters with and without irrigation. Inbred lines differed significantly in response to drought (P < 0.01): those with a lower drought sensitivity index (SI) (more resistant) originated from the drought-prone regions characterized by smaller plant size (r = 0.93), and more pods and seeds per plant (r ≥ 0.90) regardless of seed size, while lines with higher SI (more sensitive) were those which mainly exhibited higher yield under favourable conditions accompanied by a greater biomass. In a greenhouse experiment under mild drought (−0.15 MPa soil water potential), comparisons between relatively drought-sensitive (Adriewaalse) and drought-resistant (L7) inbred lines showed that Adriewaalse used 38 % more water than L7 and also produced 40 % more biomass. There was a stress-induced decrease in osmotic potential (ψ_s) in both lines (by 0.72 and 0.50 MPa for Adriewaalse and L7, respectively) accompanied by decreased turgor in Adriewaalse and increased turgor in L7. The difference in drought-induced solute accumulation between lines was diminished when solute accumulation due to water loss and growth inhibition was considered, which indicates that solute accumulation was the result of a concentration effect. Similarly, lower SI in the field was not the result of osmotic adjustment, as the relationship between SI and drought-induced decrease in ψ_s was negative. The water use efficiency of both inbred lines increased markedly with increasing water deficit, though there was no difference between the lines. It was concluded that differences in drought resistance between these inbred faba bean lines were manifested through plant size-induced water demand (avoidance) but were not associated with osmotic adjustment (tolerance).     

Drought stress in sunflower causes inhibition of seed filling due to reduced cell-extension growth

Cultivation of sunflower (Helianthus annuus L.) as one of the most important oil crops is of great importance, especially with focus on drought tolerance under the current climate change. Less precipitation and increasing temperatures lead to more regions with drought problems. In a container experiment, with two different sunflower cultivars, drought stress of 40% water-holding capacity was applied at the seed-filling phase and compared to a control group with regular irrigation to 70% water-holding capacity. Four intermediate harvests during the seed-filling phase and a final harvest at maturity were conducted. During the seed-filling phase, sugar and α-amino-acid concentrations of seeds were not reduced by drought stress. Thus, assimilate availability was sufficient, pointing to no source limitation of seed development. The DNA content of the seeds was also not affected and pointed to no limitation of cell division. However, 40 days after flowering a reduction of cell extension was found. Consequently, a sink limitation occurred under drought stress. At final harvest, seed yield was significantly reduced under drought stress due to a lower single seed weight, whereas seed number per plant was unaffected. Oil concentration was not reduced by drought stress. Thus, oil synthesis did not limit oil yield. Consequently, a reduced oil yield under drought stress during the seed-filling phase was caused by a lower seed weight, which resulted from a decreased cell extension.