Conservation consequences of Chernobyl and other nuclear accidents

The explosion at the Chernobyl nuclear power plant on 26 April 1986 released vast amounts of radioactive material over an area of 200,000 km² in eastern and central Europe, affecting all living organisms. The biological impacts including the conservation consequences of this event are still poorly known even 25 years after the disaster. Here we assess the effects of this environmental disaster for conservation by focusing on two connected questions addressing the short-term ecological and the long-term evolutionary consequences: First, we pose the question of whether rare species are more impacted by radiation than common species? Second, what are the conservation consequences of elevated mutation rates due to the mutagenic effects of radionuclides from Chernobyl? Furthermore, we assess the extent to which ecological and evolutionary aspects interact. We censused breeding birds across 731 census points in Ukraine and Belarus during 3 years to assess the relationship between abundance of different species and radiation. Most bird species avoided contaminated sites and individuals were concentrated in relatively uncontaminated sites. While common species were recorded at a wide range of radiation levels, rare species were restricted to the least contaminated sites and to sites with a high biodiversity. Thus, rare species were disproportionately impacted by the accident. Mutation rates of plants and animals have increased by up to a factor 20 due to release of radionuclides from Chernobyl. Given that each slightly deleterious mutation is expected to result in a selective genetic death, and that an average fruitfly under normal conditions may carry as many as 80 mutations, the number of mutations in animals and plants around Chernobyl and hence the number of selective deaths is bound to be much higher. There is empirical evidence for highly elevated mortality rates and dramatically increased rates of reproductive failure in contaminated areas, consistent with the expected high frequency of selective deaths due to mutations. The average slightly deleterious mutation is present for 33–167 generations in Drosophila, so if these estimates are qualitatively similar in other organisms, we can expect that mutants will disperse outside contaminated areas resulting in the spread of mutations well beyond the reach of contamination with radionuclides. Therefore, it should be possible to document the gradual spread of mutations from Chernobyl. We consider that the Chernobyl disaster and other nuclear releases may have significant consequences for population size and population viability of many species due to the large number of selective deaths. These effects remain to be investigated. Finally, comparative analyses of birds revealed that species with high mitochondrial DNA substitution rates had short dispersal distances, suggesting that mutations will spread relatively short distances when they are common, but will spread longer distances in species when they are rare.     

碱茅（Puccinellia tenuiflora）对盐胁迫及渗透胁迫的适应性反应

盆栽条件下对碱茅在等渗的盐（ＮａＣｌ）及渗透胁迫（ＰＥＧ模拟）下的生长，水分含量，离子（Ｋ＋、Ｎａ＋）吸收与选择性以及渗透反应进行了比较研究。结果表明，在－０．０１～－１．５ＭＰａ渗透势范围内，随渗透势降低植株的干重及水分含量均迅速降低，ＰＥＧ胁迫比等渗的ＮａＣｌ胁迫下降幅更大。ＮａＣｌ及ＮａＣｌ＋ＰＥＧ胁迫下，随溶液渗透势的降低（或ＮａＣｌ浓度的增大）植株Ｎａ＋浓度，Ｎａ＋／Ｋ＋及对Ｋ＋（相对于Ｎａ＋）的选择性均迅速增大，而Ｋ＋浓度未显著变化。植株Ｎａ＋主要是被动吸收的结果，而Ｋ＋则是主动的选择性吸收的结果。植株渗透势随胁迫溶液渗透势降低而线性降低，ＮａＣｌ胁迫下植株渗透势约比等渗的ＰＥＧ胁迫下低－０．１４～－０．２０ＭＰａ。ＮａＣｌ胁迫下，当渗透势高于－０．９ＭＰａ时，植株渗透势的降低（渗透反应）主要可归于由Ｎａ＋积累引起的渗透调节与脱水；渗透势－０．９～－１．５ＭＰａ时，渗透调节可解释植株渗透反应的７２％～７８％（其中，由Ｎａ＋引起的渗透调节占总渗透调节的５６％～７３％），脱水可解释２２％～２８％。ＰＥＧ胁迫下，当溶液渗透势高于－０．７ＭＰａ时，植株的渗透反应主要是脱水引起的；渗透势－０．７～－１．５     

水曲柳天然优良林分选择方法和标准的探讨

本文叙述了水曲柳天然林特性,以种群立异理论为基础,采用表型选择方法进行林分群体选择,并应用数量化理论Ⅰ进行计算分析,其数学模型是:同时分析了影响林分群体生产力、单株营养面积产量的诸因子间相互关系。以林分中水曲柳立木密度(株/ha)为基础,制定了不同等级林分的群体生产力定量指标。     

新型选择性培养基检测土壤棉花黄萎病菌效果初报

介绍了一种用于检测土壤棉花黄萎病菌的选择性培养基。该培养基成份为:鲜棉叶100g,蔗糖5g,琼脂17~20g,40%PCNB0.3g,氯霉素、链霉素和青霉素各0.05g,水1000ml,pH6.4~7.0。该培养基与其它常见分离培养基相比,成份简单、操作简便,检测率显著,抑菌效果好,病菌在其上生长快、菌落典型,是一种较为理想的选择性分离培养基。     

基于全基因组重测序筛选绵羊经济性状候选基因

本文旨在通过全基因组重测序筛选绵羊经济性状有关的候选基因。利用小尾寒羊和萨福克羊各9个个体全基因组数据进行分析,计算群体分化指数(Fst)进行选择信号分析,对受选择区域进行基因注释和富集分析。共筛选出391个受选择区域(top5%ZFst值);基因本体富集(GO)分析显示,受选择的区域基因主要与G蛋白偶联的嘌呤核苷酸受体的活性和G蛋白偶联的核苷酸受体的活性有关(P<0.01);KEGG通路分析结果表明,这些基因显著富集在嗅觉传导、花生四烯酸代谢和系统性红斑狼疮信号通路(P<0.01)。ZFst值大于5的选择信号区域有51个(89个基因),其中注释到46个基因与生长发育、疾病和抗病、适应性、乳品质、生殖、毛和被毛颜色性状有关。研究结果为深入研究绵羊的经济性状形成的遗传基础和进行绵羊遗传改良提供科学依据。     

玉米新品种桂玉609的选育和应用

杂交玉米新品种"桂玉609"是广西农科院科技发展公司用自交系MH256为母本,GW309为父本杂交育成的黄色硬粒型玉米单交种,2006年5月通过广西壮族自治区品种审定委员会农作物新品种审定。该品种果穗筒形,表现优质、高产、稳产和抗旱性强的优势。     

湖北白猪优质系选育的综合选择指数制定

采用差额法与系统分析结合的方法,通过模拟商品猪生产过程进行利润分析,计算边际效益,通过基因流动法计算目标性状经贴现的标准化性状表现值,从而获得目标性状的经济加权值.最后,根据目标性状与选择性状的遗传关系,获得选择性状的经济加权值.湖北白猪优质系的综合选择指数：父系指数为ISIRE=100-1.1765 EBVdays90-1.64EBVbf90;母系指数为IDAM=100-0.9478EBVdays90-10.2889EBVbf90＋ 6.9088EBVnb.经过6个世代的选育,父系指数和母系指数分别提高11.21和10.57,达90 kg体重日龄、90kg体重背膘厚、产活仔数、父系指数、母系指数的世代遗传进展分别为-0.597 8、-0.135 0、0.023 0、2.24和2.11.     

马铃薯新品种陇薯11 号的选育

陇薯11 号是甘肃省农业科学院马铃薯研究所于1996 年以品系L9712-2（92-29-81×93-1-
204）为母本,远杂22 为父本组配杂交,从其杂交组合中经系统定向选育而成的马铃薯品种。晚熟,生育
期124 d（天）左右。薯块圆形,黄皮黄肉,芽眼深浅中等,薯皮微网纹,薯形评价较好。薯块含干物质
23.7%,淀粉18.68%,粗蛋白3.16%,VC 144.2 mg·kg^-1,还原糖0.162%。较对照陇薯5 号抗晚疫病,
田间对花叶病毒病具有较好的抗性。每667 m² 产量1 350 kg 左右,适宜甘肃省高寒阴湿、二阴地区及半
干旱地区推广种植。     

异色瓢虫显明变种对白杨毛蚜和白毛蚜选择效应研究

[目的]探究异色瓢虫显明变种对杨树主要蚜虫白杨毛蚜和白毛蚜的捕食选择趋性。[方法]在实验室条件下,在特定空间内,测定异色瓢虫显明变种对2种蚜虫不同密度值下的捕食量。[结果]白杨毛蚜和白毛蚜种群数量同步增加时,EG-S值和EJ值变化为＋1～0,EI值是在0～-1范围内依次减少,且数值变化幅度较少,表明异色瓢虫显明变种喜好捕食白毛蚜略高于白杨毛蚜;当白杨毛蚜数量不变、白毛蚜数量增加时,EG-S值和EJ值变化为＋1～∞,EI值在0～＋1范围内依次增加,表明异色瓢虫显明变种明显喜好捕食白毛蚜;当白毛蚜数量不变、白杨毛蚜数量增加时,EG-S值和EJ值变化为在＋1～0范围内依次减少,EI值在0～-1范围内依次增加,表明异色瓢虫显明变种明显喜好捕食白杨毛蚜。捕食量结果同选择指数。[结论]异色瓢虫显现变种白杨毛蚜和白毛蚜的捕食选择趋性取决于2种蚜虫的种群数量。     

高产稳产多抗棉花新品种周棉6号的选育与应用

周棉6号是周口市农业科学院以(泗331×周R-3)F<,1>代材料为母本,以(鲁742×9708)F<,3>代选系材料为父本,进行复合杂交,并对复合杂交分离群体进行多年连续选育而成的棉花新品种.2009年通过河南省农作物品种审定委员会审定.该品种在2006、2007年河南省棉花区域试验中,皮棉、霜前皮棉平均产量分别为1...