耐盐水稻种质资源的筛选

用0.8% NaCl溶液和国际水稻所水稻耐盐性9级评价方法对前人选留的38份水稻耐盐种质资源(用0.5%NaCl盐土筛选)进行了重复筛选,以期获得极端耐盐水稻种质资源.同时研究了不同盐浓度对水稻发芽率的影响.结果表明:高浓度盐溶液显著抑制水稻种子的发芽率,但品种间有较大差异;筛选出苗期极端耐盐品种6份,其中1级1份,2级4份,3级1份;极端耐盐水稻品种苗高的增长受高浓度盐溶液抑制,但品种间差异不显著;而盐溶液对极端耐盐水稻品种出叶速率的影响因品种而异.     

水稻资源开花期耐热性的全基因组关联分析

水稻在开花期对高温非常敏感,挖掘耐热种质并解析耐热性的遗传机制,有助于水稻的耐热性遗传改良.本研究选取205份国内外种质资源,在抽穗开花期对遇高温的稻穗进行标记,以高温下标记穗的结实率作为耐热指标,结合高密度SNP标记进行全基因组关联分析并初步预测候选基因.结果 表明:不同水稻种质的耐热性差异明显,高温下的结实率最低为...     

江西省早稻品种抽穗扬花期耐热性鉴定评价研究

在自然条件和人工温室模拟极端高温胁迫下对江西省生产上推广种植的37份早稻品种进行抽穗扬花期耐热性鉴定评价。以高温胁迫下结实率和结实率降低率为评价指标,对参试品种的耐热性进行综合评价。方差分析结果表明,杂交水稻组合间在自然条件和高温胁迫下结实率及结实率降低率接近显著水平,说明杂交水稻组合间耐热性存在一定的差异;而常规水稻品种间在自然条件和高温胁迫下结实率及结实率降低率差异不显著,说明常规水稻品种间耐热性的差异较小。2013年高温胁迫下平均最高气温(41.3℃)比2012年高0.9℃的情况下,杂交水稻平均结实率比2012年降低8.9%,而常规水稻平均结实率仅降低1.72%,常规水稻平均结实率的降低幅度明显低于杂交水稻;常规水稻品种的耐热性强于杂交水稻组合。2013年自然条件下最高气温(36.8℃)比2012年高1.3℃,但杂交水稻和常规水稻的平均结实率反而比2012年分别高5.6%和15.0%,这可能是由于2013年自然条件下相对湿度(81.4%)比2012年高(高14.4%)所致,说明气温高于适宜的生育温度时,相对湿度的增加有助于增强水稻品种的耐热性。五丰优623、陵两优611、株两优819、株两优312等4个杂交水稻组合和湘早籼7号、嘉育948、中早35、中早25等4个常规稻品种在高温胁迫下表现为较高的结实率且结实率降低率较低,认为可作为耐高温水稻品种在水稻生产和育种中加以利用。     

196份葡萄属(Vitis L.)种质资源耐热性评价

以国家果树种质郑州葡萄圃保存的196份代表性葡萄属种质为试材,利用叶绿素荧光参数法对其耐热性进行了鉴定评价。结果表明:196份葡萄属植物的耐热性叶绿素荧光参数Fv/Fm数值在0.0792~0.6836之间,品种间抗性存在差异,耐热性服从正态分布,表现为多基因控制的数量性状。利用有序样品最优分割聚类法,将其耐热性分为弱、中、强3种类型,叶绿素荧光参数分级阈值分别对应≤0.3、(0.3,0.5]、0.5,利用该分级标准筛选出了腺枝葡萄双溪03、刺葡萄梅岭山1301、菱叶葡萄0945和和田绿葡萄等48份耐热性强的葡萄种质,起源于我国的野生葡萄耐热性整体上高于其他类群或品种。研究结果对于利用抗性亲本选育耐热葡萄新品种和葡萄抗热机理研究具有参考意义。     

基于SSR标记的宁夏水稻遗传多样性分析

选择自上世纪80年代以来的59份宁夏水稻种质,利用分布于12条染色体的82对SSR引物进行遗传多样性和遗传相似性分析。共检测到339个等位基因,品种间不同位点等位基因数目2~19个,平均4.13个。Nei基因多样性指数变幅为0.0333~0.9164,平均为0.4394。按种质释放或审定年代,55份水稻分为3组分析,随着年代的增加,等位基因数和遗传多样性指数均呈增大趋势,且3群体间等位基因数和多样性指数差异均达极显著水平（P<0.001）。UPGMA聚类分析表明,参试59份水稻种质在遗传相似系数0.78水平上聚为5大类,其中第Ⅰ类为1份香稻种质;第Ⅱ、Ⅳ类均为3份种质;第Ⅲ类有5份种质,与吉林水稻相似;绝大多数品种被聚为第Ⅴ类,占参试材料数的79.7％。对比宁夏水稻选育品种系谱,大多数种质具有宁夏骨干亲本红旗12、京引39、东方红2号、京引59等的血缘,种质间亲缘关系较近。虽然近年来宁夏水稻的遗传多样性有增加的趋势,但遗传基础狭窄,参试种质的相似系数在0.75以上,最高达0.97。应继续加大力度引进和创新亲本材料,拓宽宁夏水稻的遗传基础。     

不同棉花种质资源耐热性的田间鉴定

随着全球气候变暖,高温胁迫已经成为影响棉花产量的主要因素之一。中国棉花种植区,在7月和8月棉花花铃高峰期经常出现周期性极端高温胁迫,导致蕾铃脱落,降低了产量,因此棉花耐热性种质的筛选迫在眉睫。本试验在新疆吐鲁番自然高温条件下,调查200份不同棉花种质资源的脱落率、花粉活力、叶片萎蔫程度、花粉形态、不孕子率等田间性状。然后选择29份不同耐热性种质在河南安阳种植,调查30、35、40、45和50℃离体培养条件下的花粉萌发率。不同耐热性种质资源在自然高温条件下的鉴定指标和室内离体培养花粉萌发率存在着极显著的差异。而且不同鉴定指标间也存在着不同的相关性。结合田间调查结果和花粉离体培养萌发率,将29份种质划分为耐高温型、较耐高温型、高温较敏感型和高温敏感型种质,并初步确定了耐热性的鉴定指标。     

水稻种质资源芽期耐冷性的鉴定与评价

对新收集的879份水稻种质资源进行了水稻芽期耐冷性的鉴定与评价,从中筛选出芽期耐冷性极强的水稻种质资源39份,均为贵州地方粳稻品种.供试粳稻品种61.23%具有强芽期耐冷性(3级),而籼稻品种只有13.77%具有强芽期耐冷性(3级 ),粳稻品种的芽期耐冷性显著强于籼稻品种.无论籼稻,还是粳稻,贵州地方稻种的芽期耐冷性显著强于来自其他地区的品种,从贵州地方稻种中挖掘极强耐冷种质资源的潜力较大 .     

不同棉花种质资源耐热性鉴定

随着全球气候变暖,高温胁迫已经成为影响棉花产量的主要因素之一.中国棉花种植区,在7月和8月棉花花铃高峰期经常出现周期性极端高温胁迫,导致蕾铃脱落,降低了产量,因此棉花耐热性种质的筛选迫在眉睫.本试验在新疆吐鲁番自然高温条件下,调查200份不同棉花种质资源的脱落率、花粉活力、叶片萎蔫程度、花粉形态、不孕子率等田间性状.然后选择29份不同耐热性种质在河南安阳种植,调查30、35、40、45和50℃离体培养条件下的花粉萌发率.不同耐热性种质资源在自然高温条件下的鉴定指标和室内离体培养花粉萌发率存在着极显著的差异.而且不同鉴定指标间也存在着不同的相关性.结合田间调查结果和花粉离体培养萌发率,将29份种质划分为耐高温型、较耐高温型、高温较敏感型和高温敏感型种质,并初步确定了耐热性的鉴定指标.     

云南稻种核心种质不同生态群间分蘖初期耐热性鉴定

对1281份云南稻种核心种质分蘖初期耐热性鉴定结果表明(1)初步筛选出分蘖初期耐热品种283份,其中1级耐热品种2份,分别是矮子糯和团结糯,3级281份,两者共占22.1%.(2)明确云南不同生态群间耐热性的差异,其强弱依次为爪哇群＞晚籼群＞早中籼群＞冬籼群＞普通群＞光壳群.(3)耐热性强弱与籼粳、水陆、有无颖毛密切相关,而与粘糯关系不大.     

砧用南瓜品种资源耐热性鉴定及形态指标选择

高温是制约黄瓜生产的重要非生物胁迫因子之一。黄瓜(Cucumis sativus L.)嫁接苗能够有效缓解高温胁迫危害,但目前黄瓜嫁接砧木品种并不多。为此,本研究收集了国内外48份砧用南瓜种质,对萌发期和幼苗期进行高温处理(38℃和42℃),通过UPGMA聚类分析,鉴定其耐热性,并筛选适宜的形态指标。共测定了10个性状(发芽率、发芽势、发芽指数、活力指数、株高、茎粗、全株鲜重、全株干重、壮苗指数、热害指数)指标。结果表明,48份砧用南瓜种质耐热性在萌发期及幼苗期都可以分为4类。在2个时期皆表现出较耐高温的种质为日本绿霸和日本强力士;对高温敏感的种质有11份。种子相对发芽势、相对发芽指数、相对活力指数以及幼苗相对干重可作为砧用南瓜种质资源耐热性鉴定的可靠指标。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.