Predicting release and aquatic effects of total dissolved solids from Appalachian USA coal mines

Appalachian USA coal mines have been implicated as major stressors to aquatic life in headwater streams via discharge of total dissolved solids(TDS).This paper summarizes column leaching studies of spoils(n>50)and refuse and TDS effects on local water quality and biotic response.The initial pH of most materials is near-neutral.Initial specific conductance(SC)values range from 500-1,000 to >3,000 μs/cm,but 2/3 of materials drop below 500 ls/cm after several pore volumes of leaching.Studies of mining-influenced streams have found altered aquatic life,relative to natural conditions with no mining influence,at SC ranging from-200 to-700 ls/cm with depressed aquatic life consistently associated with elevated TDS;mechanisms causing such effects are under investigation.We suggest that active mine operations should be modified to place high TDS producing materials in ways that reduce contact with percolating drainage waters.

Geographical distribution of GmTfl1 alleles in Chinese soybean varieties

Stem growth habit is an important agronomic trait in soybean and is subject to artificial selection. This study aimed to provide a theory for genotypic selection of stem growth habit for breeding purposes by analyzing the alleles of Gm Tfl1 gene in Chinese soybean varieties and establishing a database of Gm Tfl1 variation. Using knowledge of insertion and deletion(Indel) in the non-coding region and four single-nucleotide polymorphisms(SNPs) in the coding sequences of the Gm Tfl1 gene, four CAPS and one Indel markers were developed and used to test 1120 Chinese soybean varieties. We found that the dominant Gm Tfl1 allele was prevalent in accessions from the Northern ecoregion, whereas the recessive allele, Gmtfl1, was more common in the Southern ecoregion, and the proportions of Gm Tfl1 and recessive alleles were respectively 40.1% and 59.9% in the Huang-Huai ecoregion. The proportion of Gm Tfl1 decreased and that of Gmtfl1 increased, gradually from north to south. Allele Gm Tfl1-a was present in higher proportions in the Huang-Huai spring, Huang-Huai summer, and Northern spring sub-ecoregions than that in the other sub-ecoregions. Gm Tfl1-b was common in the Northeast spring, Northern spring and Southern summer sub-ecoregions. Gmtfl1-ta was found mainly in the Huang-Huai spring,Huang-Huai summer and Southern spring sub-ecoregions. The Gmtfl1-ab allele was distributed in all six soybean sub-ecoregions. The Gmtfl1-bb allele was distributed mainly in the Huang-Huai spring and summer and Southern spring and summer sub-ecoregions,but the Gmtfl1-tb allele was detected only in the Huang-Huai summer sub-ecoregion. The distributions of Gm Tfl1 and Gmtfl1 have shown no large changes in nearly 60 years of breeding, but the frequency of the recessive genotype Gmtfl1 has shown a rising trend in the last 20 years. This study provides a theoretical foundation for breeding new soybean varieties for different ecoregions.

Invariance in the Seasonal Median Dates for Mono-Modal Monsoonal Rainfall Distribution over the Semi-Arid Ecotone of Sub-Saharan West Africa

Seasonal distribution of mono-modal, monsoonal rainfall across the semi-arid ecotone of sub-Saharan of West Africa is highly variable and unpredictable. The ever-present risk of drought and crop failure in this environment often results in food shortages that are met by emergency food aid. Humanitarian assistance planners would be better prepared for such interventions in a timely manner if they have reliable indicators that forewarn the impending failure of the rains. A good indicator would be a characteristic of the seasonal rainfall distribution that can be shown to be reasonably invariant over time and space. The objective of this study is to investigate whether such invariance existed for the seasonal median date (meaning the date when 50% of the seasonal total occurs). Such invariance is expected since the sun’s cyclic declination forces the advance and retreat of the Inter-tropical Front over West Africa. We examined the statistical properties of the seasonal median date for 1349 station-years of rainfall records for 30 rainfall stations in Burkina Faso and Niger with coordinates ranging from 9.88° to 18.5° north latitude and -4.77° to 13.2° longitude. The results showed that the median date was quite narrowly distributed over years with rather weak dependence on geographical coordinates. It can therefore be used as a reasonable ex-ante indicator of the success or failure of the rains as the rainy season progress.

Potential Contribution of Combined Atmospheric Ca^(2+) and Mg^(2+) Wet Deposition Within the Continental U.S. to Soil Inorganic Carbon Sequestration

Soil inorganic carbon(SIC)stocks continuously change from the formation of pedogenic carbonates,a process requiring inputs of Ca2+and Mg2+ions.This study ranked the soil orders in terms of potential inorganic carbon sequestration resulting from wet Ca2+and Mg2+deposition from 1994 to 2003 within the continental United States.The analysis revealed that average annual atmospheric wet deposition of Ca2+and Mg2+was the highest in the Central Midwest-Great Plains region,likely due to soil particle input from loess-derived soils.The soil orders receiving the highest total average annual atmospheric wet Ca2+and Mg2+deposition,expressed as potential inorganic carbon formation(barring losses from erosion and leaching),were:1)Mollisols(1.1×108kg C),2)Alfisols(8.4×107kg C),3)Entisols(3.8×107kg C),and 4)Aridisols(2.8×107kg C).In terms of area-normalized result,the soil orders were ranked:1)Histosols(73 kg C km-2),2)Alfisols and Vertisols(64 kg C km-2),3)Mollisols(62 kg C km-2),and 4)Spodosols(52 kg C km-2).The results of this study provide an estimate of potential soil inorganic carbon sequestration as a result of atmospheric wet Ca2+and Mg2+deposition,and this information may be useful in assessing dynamic nature of soil inorganic carbon pools.

西藏和埃塞俄比亚大麦6个同工酶位点遗传变异的对比分析

我们对比分析了埃塞俄比亚(简称埃)和西藏共777份栽培大麦材料在6个同工酶位点(Est1、Est2、Kst3、Est4、Acp1和Got1)的遗传变异。结果表明,无论是从单个位点上分析还是在多位点基因组合形式上评价,埃大麦与西藏大麦群体在遗传组成和多位点基因结构上都有着很大的差异。遗传多样性对比分析表明,从单个位点基因类型看,西藏大麦与埃大麦遗传变异程度大致相当,但从多位点基因组合形式看,西藏大麦遗传多样性程度极显著地高于埃大麦。

中国大豆花叶病抗源和抗性鉴别寄主的鉴定与评价

收集大豆抗大豆花叶病(SMV)抗源和鉴别寄主40份,通过接种Cho和Goodm an划分的抗大豆花叶病毒株系SMV G1-G7,了解这些材料对该株系的抗性反应。同时比较了其中部分材料对中国学者划分的SMV Sc1-Sc17株系的抗性反应。结果感病材料无论对SMV G1-G7株系,还是SMV Sc1-Sc17株系均表现感病;但是,齐黄1、科丰1、早18和8101等对SMV G1-G7株系均表现抗病的材料,对SMV Sc1-Sc17株系却表现出部分抗病;而另外一些材料,如:诱变30、徐豆1、文丰5、铁6915、齐黄10和Harosoy等对SMV G1-G7株系的抗性反应却与北美的鉴别寄主相同。结果表明:无论是对SMV G1-G7株系,还是对SMV Sc1-Sc17株系,抗病材料的抗性遗传基础是相似的;中国一些大豆花叶病毒株系的致病力强于国外的株系。因此,结合国外的SMV株系鉴定系统,创建一套统一的SMV株系鉴定系统是可行的。

Efect of Post-Irrigation Aeration on Growth and Quality of Greenhouse Cucumber

Rhizosphere aeration,irrigation with aerated water,and post-irrigation aeration would positively impact crop growth and yield.The objective of this study was to determine the efect of 4 post-irrigation aeration levels on plant growth,yield,irrigation-use efciency(IUE),and fruit market and nutritional quality of greenhouse cucumber under subsurface drip irrigation(SDI)and furrow irrigation(FI).The post-irrigation aeration levels were 0.00,0.50,0.75,and 1.00 times half the estimated porosity of the plot rhizosphere.The experimental design was a two-factor split-plot in randomized complete blocks with irrigation(FI and SDI)as the main treatments and4 aeration levels as the sub-treatments.Ridge and furrow main plots(2.4 m×2.4 m)with 4 ridges were replicated 5 times.Each of the4 ridges(1.44 m2in area)in the main plots was used as a sub-treatment plot.The results showed that post-irrigation aeration enhanced greenhouse cucumber plant growth,yield,IUE,and fruit market and nutritional quality.These parameters generally increased with increasing aeration levels under both FI and SDI.The aeration efect was generally higher under SDI than FI,and the IUE under SDI was almost twice that under FI.Further investigation would be required to elucidate the plant physiological mechanisms and soil processes responsible for the observed efects.