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关键词： asymmetrical hybridization   Dryopteris   ferns   gene flow   polyploidy   reproductive isolation  

摘要： Hybridization is an important evolutionary force in plants, but the mechanisms underlying it have not been well studied for many groups. In particular, the drivers of non-random patterns of interspecific gene flow (asymmetrical hybridization) remain poorly understood, especially in the seed-free vascular plants. Here, we examine patterns of asymmetrical hybridization in twowidespread fern hybrids from eastern North America and study the role of gametophyte ecology in the determination of hybridization bias. We characterized the maternal parentage of >140 hybrid sporophytes by sequencing a c. 350-bp region of chloroplast DNA (cpDNA). To identify factors contributing to patterns of asymmetrical hybridization, we cultured gametophytes of the parental species and evaluated critical aspects of their reproductive biology. We found that asymmetrical hybridization was prevalent across the populations of both hybrids. Reproductive traits varied across species and suggest that selfing potential, antheridiogen responsiveness, sperm dispersal capacity and gamete size all contribute to the mediation of the direction of hybridization in this group. Our findings suggest that asymmetrical hybridization in ferns is driven by an array of reproductive traits. This study helps to sharpen and define a mechanistic understanding of patterns of hybridization in this group and demonstrates the importance of considering gametophyte biology when studying evolutionary processes in ferns.

关键词： Arsenic transport   gold nano-particles   osteoporosis   Trichoderma sp.  

摘要： plant life is a major facet of plant science research. In the face of several unprecedented challenges, including the impending issues of climate change, environmental pollution, biodiversity loss, genetic erosion, malnutrition and diseases, plant science demands a synthetic and systems approach to find affordable solutions to the above challenges. The challenge before plant biologists is, therefore, not limited only to discovering and documenting the diversity in plants, fungi and microbes, but also in identifying the useful properties in them. A premier plant science research centre under the patronage of the Council of Scientific and Industrial Research (CSIR), the Lucknow-based National Botanical Research Institute (CSIR-NBRI) is known for its excellence in enriching the knowledge base on plant diversity of India and its systematic documentation, conservation and sustainable utilization through traditional and advanced biotechnological approaches. CSIR-NBRI has a wholesome expertise in plant biodiversity, biotechnology and bioinformatics. The Institute has developed technologies and knowhow for the preparation of a number of value-added herbal products as well as microbial technologies for the development of biofertilzers, bioinoculants and bio-pesticides. Its translational research on microbial consortia-based bio-inoculants, executed along with the Directorate of Agricultural Research, Govt of Uttar Pradesh won the prestigious CSIR S&T Award for Rural Development for the year 2011.

关键词： 多重PCR   植物生物学   应用  

摘要： 多重PCR是近年来兴起的一项分子生物学技术,它是在一个反应体系中同时扩增多个核酸片段的PCR技术,具有高效快捷、成本低廉、适合大量样本分析与鉴定等优点。就多重PCR技术原理及其在植物种质、转基因植株、植物病害、抗病基因和植物育种检测中的应用现状进行了综述,并对其应用前景作了展望。

关键词： 教学背景   生物学概念   对照实验   初中生物   发现过程   事物本质   学习过程   海尔蒙特   银边天竺葵   概念图  

摘要： 2011版《初中生物课标》的一个突出亮点是重视生物学重要概念的教学。概念是认识事物本质内涵的思维单位,是学生学习的主要内容,也是引导学生思考和探究的重要素材。本文以＂植物光合作用＂为例谈生物学重要概念的建构方法。一、教学背景与分析本课重点是通过了解光合作用的发现过程,明确探究实验思想是科学家的实验灵魂,建立光合作用的概念。教学难点是绿叶在光下制造有机物的单一变量对照实验设计及结果分析。

关键词： Haemophilus influenzae   middle ear   otitis media   pneumococcal vaccination   Streptococcus pneumoniae  

摘要： AimThis study aims to describe the microbiology of middle ear fluid (MEF) in a cohort of children vaccinated with Streptococcus pneumoniae conjugate vaccine (PCV7) having ventilation tube insertion. Nasopharyngeal (NP) carriage of otopathogens in these children is compared with children without history of otitis media. MethodsBetween May and November 2011, MEF and NP samples from 325 children aged <3 years were collected in three major centres in New Zealand at the time of ventilation tube insertion. An age-matched non-otitis-prone comparison group of 137 children had NP samples taken. A questionnaire was completed by both groups. ResultsImmunisation coverage with at least one dose of PCV7 was 97%. Haemophilus influenzae was cultured in 19.4% of MEF and was polymerase chain reaction (PCR) positive in 43.4%. *** and Moraxella catarrhalis were cultured in <10% of MEF samples but were PCR positive for 23.1% and 38.7%, respectively. *** was the most common organism isolated from NP samples (60%) in the grommet group, while *** (56%) was the most common in the non-otitis prone group. *** was more commonly found in the nasopharynx of children with ear disease (41% vs. 29%). 19F was the most prominent *** serotype in NP samples of both groups, but no serotype dominated in MEF. Ninety-five per cent of *** isolates were confirmed to be non-typeable ***. ConclusionIn this cohort of children with established ear disease requiring surgical intervention, non-typeable *** is the dominant pathogen in both the nasopharynx and MEF.

关键词： Halophytes   Phytoremediation   Phytoextraction   Phytostabilization   Phytoexcretion   Heavy metals   Salt toleranc  

摘要： Halophytic plants are characterized by their ability to survive, even thrive, at concentrations of sodium and chloride ions that would be toxic to most crop species. Given the diminishing prospects for the availability of fresh water for agriculture, halophytes represent an important resource for both our understanding of the fundamental physiological mechanisms in salt stress adaptation and utilization of saline waters for agriculture. Mechanisms of adaptation that allow halophytes to survive high salt concentrations may be not exclusive to sodium and chloride and may confer tolerance to other toxic ions, including the loosely defined family of heavy metals. It has been recently shown that a number of these halophytes do indeed have ability to accumulate heavy metals or tolerate high levels of toxic ions in the environment. These abilities make some halophytes excellent candidates for phytoextraction and phytostabilization of heavy metals in contaminated soils. This review addresses the general deleterious effects of heavy metals in plants, present known mechanisms of adaptation to heavy metal stress in halophytes and discusses the potential of halophytes for phytoremediation of contaminated soils. Considering the multifaceted potential of halophytes for biomass production in marginal and/or extreme environments, their potential role in the broader context of agriculture and food security should be further explored. (C) 2014 Elsevier B.V. All rights reserved.

关键词： 未知功能结构域蛋白家族(DUFs)   基因表达   植物   生物学功能  

摘要： 未知功能结构域蛋白家族(domains of unknown function protein families,DUFs)是一大群并未表征功能的蛋白家族,其蛋白结构中包含至少一个高度保守的DUF结构域。在众多的DUFs蛋白家族中存在一些植物特有的DUFs蛋白家族,其参与调控植物生长发育、植物对病虫害的防御反应和植物对非生物胁迫的应答反应等生物学过程。本文对近几年关于植物DUFs基因参与上述生物学功能方面的研究进行了综述,旨在为未知功能基因的挖掘及其调控机制的阐明提供基础资料。

关键词： 热激蛋白70   基因家族   分子伴侣   调控机制   进化分析  

摘要： 植物热激蛋白70(heat shock protein 70,Hsp70)是热激蛋白家族中保守、普遍表达的家族,有两个主要功能区:N端核酸结合区和C端底物结合区。通常Hsp70具有分子伴侣功能,参与新生蛋白的折叠、转运、重折叠变性蛋白、协助降解变性蛋白;Hsp70不仅受高温胁迫诱导,且受其它多种胁迫诱导;同时,Hsp70参与植物正常发育过程。Hsp70基因分布广泛,序列高度保守,在植物基因组中以基因家族形式存在,最近广泛用于遗传多样性和系统发育研究。文章对植物中Hsp70的基因家族、结构、表达调控机制和生物学功能进行了综述。

关键词： 细胞生物学   竞赛试题   奥林匹克   植物学   国际   离子化合物   必需元素   混合物  

摘要： 理论Ⅱ整套试题总分：93．4分，时间：180min可能是多选题，每个空格都需要填写。例如：注意：一些问题可能标记为“忽略”或“删除”。不要回答这些内容。细胞生物学1．从一个学校的不同地方收集到4种微生物的混合物，每个微生物混合物培养在一个含有除碳之外的所有必需元素（离子化合物形式）的培养基中。

关键词： 掌叶木   开花生物学   繁育系统   花性别  

摘要： 通过野外观察、杂交指数估算、授粉特性分析及人工控制授粉试验等方法对珍稀濒危植物掌叶木(Handeliodendron bodinieri)开花生物学特性和繁育系统进行研究。结果表明:(1)掌叶木每年开花1次,花期在4月下旬到5月中下旬,开花的起止时间及花期的长短受当地气候影响较大;(2)花多为假两性花,即形态上为雌、雄蕊完整的两性花,而功能上为雌、雄蕊选择性败育形成的单性花,偶见雌、雄蕊可育的真两性花植株;单性花通常雌、雄异株,且雌株较雄株少,花序较雄株短5.6 cm,花期也较雄株短2周左右,雄株花序上偶尔见雌花单花;(3)单花经历萌动、露白、展开、盛开、凋落5个阶段,历时5~6 d;雄花从萌动到开花1 d的花粉活力高达90.5%,开花2 d后活力显著下降;雌花柱头在展开前部分具可授性,展开后1~3 d均具可授性,花粉活力与柱头可授性重叠;(4)雄花单花花粉量为51 461个,雌花单花胚珠数6,花粉胚珠比(P/O)为8 577,杂交指数为4,结合人工授粉、套袋、套网和自然授粉坐果率判断,掌叶木繁育系统为专性异交,传粉过程需要传粉者,可能存在无融合生殖。(5)掌叶木花性别分化复杂,可孕花数量较不孕花少,可育雌、雄蕊存在较大的空间隔离,加之不稳定的传粉环境,可能是其濒危的重要生殖生物学原因。