利用荧光SSR标记鉴定茶树自然杂交后代遗传背景

为研究茶树自然杂交后代遗传背景,分析不同茶树自然杂交后代遗传差异,本研究利用24对EST-SSR标记对82个茶树自然杂交后代和34个福建主要栽培品种进行分子标记,分析了茶树自然杂交后代的亲缘关系、群体遗传多样性、亲本模拟分析。结果表明：(1)24对SSR标记共检测到157个多态性位点,平均等位位点数为6.542个,Nei’s多样性指数平均为0.588,Shannon’s 信息指数平均为1.182,平均观测杂合度和期望杂合度分别为0.577和 0.591。(2)遗传距离聚类将个供试样品划分为4类,群体1主要为‘丹桂’及其自然杂交后代;群体2主要为‘丹桂’、‘黄观音’自然杂交后代与福建省乌龙茶品种;群体3主要为‘白鸡冠’及其自然杂交后代;群体4主要为福建省绿茶品种。(3)‘丹桂’、‘白鸡冠’、‘黄观音’自然杂交后代群体与福建主要栽培品种的遗传距离分别为0.079、0.117、0.107。(4)群体1亚群b内‘丹桂’自然杂交后代模拟亲本准确率为77.8%,模拟父本主要为福建乌龙茶品种,与群体2(亚群a)的遗传相似度、遗传分化系数、基因流分别为0.899、0.043、5.480。(5)AMOVA分析结果显示,有88.52%的遗传变异来自群体内部的个体间,表明遗传变异主要发生在群体内。     

天然产物抗氧化构效关系及作用机理的研究概况

本文简介了近十年来天然抗氧化剂的研究概况,讨论了天然产物抗争氧化活性的构效关系及作用机理。     

茶树品种‘金牡丹’自然杂交后代遗传鉴定

为了对‘金牡丹’茶树自然杂交后代进行遗传鉴定,利用EST-SSR毛细管电泳荧光标记技术对65个金牡丹自然杂交后代进行研究。结果表明,28对SSR标记共扩增出192个等位片段,平均等位基因数(Na)、平均观测杂合度(Ho)及遗传多态信息量(PIC)分别为6.86、0.540、0.532。单亲基因型已知时的累积排除概率为0.999,说明选择的28对SSR标记位点具有高度的多态性和较高的排除概率,适用于遗传分析和个体的亲子鉴定。15个‘金牡丹’自然杂交后代的遗传鉴定结果表明,MD44、JMD45、JMD47、JMD32为早生绿茶类型;JMD51、JMD53为闽北肉桂乌龙茶类型;MD2、JMD56为闽南‘铁观音’乌龙茶类型;JMD24、JMD26、JMD29、JMD55、JMD59、JMD27、JMD61为‘黄棪’乌龙茶类型。     

The response of lichens inhabiting exposed wood of spruce logs to post-hurricane disturbances in Western Carpathian forests

We investigated which of the following environmental factors: the number of years since the windthrow of the tree (the age of dead wood), the phytocenosis (the type of forest community), altitude, exposure, wood hardness and the spatial scale of forest disturbances (small gaps with a few fallen spruces vs large-area windthrows) contributed to the diversity and abundance of lichens inhabiting the exposed wood of windthrown spruce trees in Polish Western Carpathian forests. Both Shannon H index and sum of coverage coefficients rose with increasing age of the wood, levelling off after 11–14 y (diversity) and 14–17 y (abundance). This factor appeared to be the most important for this group of lichens, but the significant positive impact of large-area windthrows on the lichen abundance was also demonstrated by using a GLM model. The age of the wood we precisely determined on the basis of data on Norway spruce mortality collected annually in permanent plots of the Gorce National Park since 2000. Using the Shore durometer we linked the course of the wood-inhabiting lichen succession with wood decay more precisely than before. The largest number of species was associated with medium hard wood, i.e., 51 < x ≤ 80 on the Shore scale. Based on the NMDS analysis, we distinguished four age groups of logs, differing in lichen abundance and defined by the dominance of distinctive species. A large number of usually corticolous lichen species used the wood of windthrown spruce logs as an optional habitat to survive large-scale, post-hurricane forest disturbances.     

Variability of plant species diversity in Swedish natural forest and its relation to atmospheric deposition

Within a subprogram of Integrated Monitoring (IM), understorey vegetation in Swedish natural forests was observed at fifteen reference sites over the country for twelve seasons, 1982–1993. The main task of the subprogram was to assess the impact of atmospheric deposition, mainly sulphur and nitrogen, on natural vegetation through time. The present study is focused on the variability of plant species diversity at community level and the possible impact of sulphur and nitrogen deposition. Species richness, evenness and diversity varied greatly among the sites, and between years within each site. Regarding only coniferous forests the species richness was higher in the north than in the south. But the effects of site condition and atmospheric deposition were not clarified. Changes in species diversity through time differed from site to site. No overall temporal trend was found. The atmospheric deposition of sulphur and nitrogen demonstrated a clear geographical pattern being low in the north-west and high in the south-west. Sulphur deposition declined significantly in Southern Sweden during the period. We concluded that the species diversity of understorey vegetation at the Swedish IM sites was not significantly influenced by atmospheric deposition. The changes observed are explained as natural processes.     

Arthropod Natural Enemies of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in India

Helicoverpa armigera Hubner Lepidoptera: Noctuidae is one of the most serious insect pests in the Old World. In India, it causes substantial losses to legume, fibre, cereal oilseed and vegetable crops. This paper reviews the literature on the biology, ecology, efficacy, rearing and augmentation of endemic parasitoids and predators, as well as exotic parasitoids introduced and released in India. It also provides updated lists of H. armigera natural enemies native to India. In addition, reports of augmentative releases of Trichogramma spp., the most extensively studied natural enemy of H. armigera are summarized.     

Gathered fruits and cultivated plants at Bercy (Paris), a Neolithic village in a fluvial context

Recent rescue excavations at Bercy (Paris), a site on the alluvial plain of the Seine valley, yielded plant remains which are associated with the recent occupation phase dating from the middle Neolithic II (Chasséen), when a village was established on the former channel of the river Seine. Various contexts (the channel, the flat lower part of the bank, and several archaeological features) have been studied and 84 taxa have been identified. Cultivated plants are represented by Triticum aestivum/durum, T. dicoccum, T. monococcum and Hordeum vulgare. Among the wild plants with potentially edible fruits or seeds, only very few satisfy the various criteria for association with human activities: Corylus avellana, Vitis sylvestris, Cornus sanguinea, Quercus sp. and Prunus spinosa of which carbonized fruits were also present, were found in archaeological features and were very abundant. Though not found in archaeological features, we consider that Crataegus monogyna (carbonized and well represented) and Rubus spp. (especially abundant) were not deposited there naturally and had also been intentionally collected. Finally, it is suggested that the allochthonous (varied) origin of these taxa is the reason why there are no concentrations of their fruits in the channel. The exploitation of wild seeds and fruits appears to have been very selective. All other wild taxa can be attributed to natural deposition.     

Evidence for plant exploitation and vegetation history from three Early Neolithic pre-pottery sites on the Euphrates (Syria)

Archaeobotanical results based on a limited number of samples from three aceramic sites dating from 9800 to 7800 B.P., which are under excavation in the valley of the Middle Euphrates, are discussed. The finds are presented simply by presence, and are compared to the contemporary vegetation and finds from similar sites. Carbonised plant remains recovered by flotation from levels dated to between 9800 and 9200 B.P. (Dja'de and Jerf al Ahmar) indicate that wild cereals (einkorn wheat, rye and barley) and pulses (lentils, pea and bitter vetch) were exploited. Other plants such as wild grasses, Pistacia, wild almond and oak, suggest that the local vegetation provided a rich diversity of resources. A study of possible weed taxa is being carried out in order to see whether this assemblage could be used to identify the cultivation of morphologically wild cereals for this period. Ninth millennium B.P. levels at Halula see the appearance of domestic crops such as emmer, naked wheat and barley, but wild-type cereals persist. The cultivars appear to have been introduced from elsewhere and later ninth millennium B.P. species include olive and flax. Ash, vine, maple, plane, alder and elm from the gallery forest, wild rye, wild einkorn, deciduous oak, wild almond, Pistacia, and Pyrus, from the hinterland, indicate cooler conditions.     

The origin of adaptive mutants: Random or nonrandom?

Several recent reports have claimed that adaptive mutants in bacteria and yeast are induced by selective conditions. The results of these reports suggest that mutants can arise nonrandomly with respect to fitness, contrary to what has been widely accepted. In several cases that have received careful experimental reexamination, however, the detection of seemingly nonrandom mutation has been explained as an experimental artifact. In the remaining cases, there is no evidence to suggest that cells have the capacity to direct or choose which genetic variants will arise. Instead, current models propose processes by which genetic variants persist as mutations only if they enable cell growth and DNA replication. Most of these models are apparently contradicted by experimental data. One model, the hypermutable state model, has recently received limited circumstantial support. However, in this model the origin of adaptive mutants is random; the apparent nonrandomness of mutation is merely a consequence of natural selection. The critical distinction between the origin of genetic variation (mutation) and the possible consequence of that variation (selection) has been neglected by proponents of directed mutation.     

The molecular analysis ofbrown eye color mutations isolated from geographically discrete populations ofDrosophila melanogaster

A large proportion of spontaneous mutations inDrosophila melanogaster strains of laboratory origin are associated with insertions of mobile DNA elements. As a first step toward determining whether spontaneous laboratory mutations are predictive for mutational events occurring in the wild, recessivebrown (bw) eye color mutants were isolated. By inbreeding the progeny of wild-caughtDrosophila melanogaster females,bw mutations were isolated from seven separate geographic sites distributed among Japan, California, Siberia and Hungary. Among a total of 14 mutations studied, no case of transposon mutagenesis was found. At least 4 mutations are associated with small deletions in thebw gene. The remainder are inseparable from wild-typebw by Southern analysis and are presumed to be basepair changes or very small indels. Although only two spontaneousbw mutants of laboratory origin have been analyzed molecularly, one is a mobile element insertion.