杜仲种质资源果实性状变异及综合评价

[目的 ]分析杜仲种质资源果实性状变异规律并进行综合评价,为杜仲良种选育和开发利用提供理论依据和遗传材料。[方法 ]基于我国18个省(市、区)331份杜仲种质资源,针对杜仲果实19个主要性状,采用相关性分析、聚类分析和主成分分析等方法,分析果实性状变异状况,评价并筛选优良种质。[结果 ]杜仲果实性状变异系数为4.64%～25.79%,平均变异系数为12.65%,变异系数较高的为包裹种仁果皮百粒质量(25.79%)、种仁百粒质量(22.32%)、种仁体积指数(22.02%)、果实体积指数(19.53%),变异系数较小的为亚麻酸(4.64%)、油酸(5.78%)、果型指数(8.04%)。果实性状遗传多样性指数介于1.657 2～2.094 7,平均为2.023 4。果实百粒质量与果实体积指数、种仁百粒质量等性状呈极显著正相关,杜仲橡胶含量与包裹种仁果皮百粒质量、果实侧径均呈极显著正相关,与种仁粗脂肪含量呈显著负相关。聚类分析将杜仲种质资源划分为3个类群,类群Ⅰ为小果型类群,类群Ⅱ为中型果类群,类群Ⅲ为大果型类群,初步明确杜仲种质果实不同类型。通过主成分分析,前7个主成分累积贡献率达85.169%,表明这7个主成分代表了杜仲果实性状的大部分信息,针对油用、橡胶用和综合利用等不同用途进行评价,分别筛选出10份最优种质。[结论 ]杜仲种质资源果实性状表现出丰富的变异,以包裹种仁果皮百粒质量、种仁百粒质量等产量指标变异最大,为杜仲优良种质选育提供了可能,针对不同用途筛选的杜仲最优种质,为我国杜仲良种选育及综合利用提供了优异的种质基础。     

杜仲雄花主要活性成分含量的多样性

【目的】研究不同种质杜仲雄花主要活性成分含量的遗传变异规律,比较并评价杜仲雄花主要活性成分含量的多样性,为雄花用杜仲优良资源选育和开发利用提供科学依据和材料。【方法】以193份不同种质杜仲雄花为材料,采用AlCl_3比色法测定杜仲雄花中总黄酮含量,全自动氨基酸分析仪测定氨基酸含量,HPLC法测定桃叶珊瑚苷、京尼平苷酸、绿原酸、京尼平苷、异槲皮苷、紫云英苷6种活性成分含量,并对8种活性成分含量进行变异分析、相关性分析、主成分分析和聚类分析。【结果】不同种质杜仲雄花8种活性成分含量和多样性指数均以氨基酸最高,分别为206.23 mg·g~(-1)和2.05;变异系数以京尼平苷最高,达112.00%,氨基酸最低,仅为12.52%。相关性分析结果显示:桃叶珊瑚苷、京尼平苷酸、绿原酸、京尼平苷及异槲皮苷5种活性成分间均呈极显著正相关,氨基酸除与总黄酮呈极显著正相关外,与其他活性成分相关性不显著。通过主成分分析,前4个主成分的累计贡献率达87.040%,可以用于杜仲雄花资源前期的评价选择。基于8种活性成分,将193份杜仲种质划分为5个类群,各类群8种活性成分含量之间均存在显著性差异。第Ⅰ类群种质8种活性成分含量均较低;第Ⅱ类群种质氨基酸含量最高;第Ⅲ类群种质黄酮类化合物及其组分含量最高;第Ⅳ类群种质环烯醚萜类化合物组分含量最高;第Ⅴ类群种质绿原酸和京尼平苷酸含量最高。初步明确杜仲种质雄花的不同类型。【结论】杜仲种质雄花8种活性成分含量较高,开发利用价值大,而且表现出丰富的多样性和变异,很有选择潜力和改良潜力。     

南方型黑杨种质资源表型及生长性状遗传多样性分析

为了解南方型黑杨种质材料的表型及生长性状遗传多样性,丰富黑杨种质资源遗传基础,并进一步为南方地区黑杨种质资源定向选育提供参考,选取地径、苗高、叶面积、叶长、叶宽、叶柄长、叶绿素、侧枝数、叶厚、单株总叶片、叶片干质量共11个树体性状及生理指标,同时观测记录了每个无性系的生长期和抗性,对62份南方型黑杨种质资源的13个性状进行了遗传多样性分析。结果表明:62份黑杨资源分成7个类群,各类群材料根据不同性状的相似性进行聚类,整体比较分散,具有较高的分化强度。13个性状的多样性指数H′变化范围介于0.587~1.550之间,平均值为1.098,叶片相关性状以及生长期遗传多样性较丰富。主成分分析将相关变量转化为叶片形态、单株叶片数量、抗性及生长期、侧枝数4个主成分,涵盖了13个测定性状80.953%的遗传信息。本研究首次从表型及生长相关性状等方面探明了南方型黑杨的遗传多样性,对于充分发掘黑杨资源优良基因型,进一步开展南方型黑杨遗传改良工作具有重要意义。     

基于等位基因最大化法初步构建杜仲核心种质

【目的】构建杜仲核心种质,去除基因库中的遗传冗余,为杜仲种质资源的保存、研究和利用提供依据。【方法】以国内外54个地区的887份杜仲种质资源为试验材料,基于9对基因组SSR引物和等位基因数目最大化策略构建杜仲核心种质。利用分子生物学软件和统计分析软件,通过等位基因数(n)、平均等位基因数(Na)、平均有效等位基因数(Ne)、平均Shannon指数(I)、平均Nei’s遗传多样性指数(H)、平均基因型数(Ng)、平均多态信息含量(PIC)7个遗传多样性参数及其保留比例对所构建核心种质进行评价,结合遗传多样性指数的t检验法和主坐标分析法(PCo A)验证和确认核心种质对原始种质的代表性。【结果】9对SSR引物共检测到107个等位基因,遗传多样性参数Ne、I、H分别为5.096、1.812、0.925,表明杜仲种质资源具有丰富的遗传多样性。887份杜仲种质基于等位基因数目最大化原则得到189份核心种质和698份保留种质。189份核心种质占原始种质样品数的21.3%,保存了原始种质100%的等位基因,9个SSR位点的遗传多样性参数Na、Ne、I、H、Ng、PIC的保留比例分别为100%、116.5%、108.7%、101.5%、100%、103.3%;以上参数经t检验,与原始种质在0.01水平上差异不显著,主坐标分析也表明,核心种质与原始种质的样品在分布图上有着相似的分布结构,说明构建的核心种质具有代表性。698份保留种质占原始种质样品数的78.7%,保存了原始种质86.9%的等位基因,9个SSR位点的遗传多样性参数Na、Ne、I、H、Ng、PIC的保留比例分别为86.9%、95.7%、96.7%、99.4%、77%、99%;以上参数经t检验,与原始种质在0.01水平上差异不显著。【结论】构建的核心种质具有代表性,保存了原始种质全部的等位基因和基因型,核心种质与原始种质群体的6个遗传多样性参数(Na、Ne、I、H、Ng、PIC)差异不显著,核心种质与原始种质的样品在分布图上有着相似的分布结构。核心种质的遗传多样性参数均高于保留种质,在杜仲种质资源保存和建立育种群体时应优先使用核心种质。本研究为杜仲优异基因发掘和新品种选育奠定基础。     

油橄榄品种表型和SSR标记的多样性及聚类分析

[目的]利用表型性状和分子标记,对我国油橄榄品种进行鉴定和遗传多样性研究,有利于种质资源保存和利用,对了解油橄榄品种的组成结构及未来的引种和育种工作都具有重要意义。[方法]以甘肃省陇南市17个油橄榄品种为研究材料,利用表型上15个数量性状、18个质量性状和8个SSR荧光标记分别进行多样性和聚类分析。[结果]各性状在品种间存在显著差异,数量性状和质量性状的表型多样性指数分别介于1.579 2.089和0.3621.091,8个SSR位点共检测到51个等位基因变异,平均每个位点等位基因数为6.375个,利用表型性状和SSR标记可以将17个品种完全区分开。[结论]17个油橄榄品种具有较丰富的表型和遗传多样性,基于表型数量性状、质量性状和SSR标记的聚类分析结果,判别品种间遗传关系的结果有一致的,也存在一定差异。对于表型性状相似的品种,需结合SSR标记进行品种鉴定。     

不同产地杜仲雄花的非靶向代谢组学比较与分析

[目的]比较分析不同产地杜仲雄花的代谢组学差异,为杜仲雄花高效利用以及规模化精准评价杜仲种质资源提供参考.[方法]利用超高效液相色谱-四级杆飞行时间质谱技术(UPLC-QTOF/MS)测定河北安国、四川广元、河南新乡、河南洛阳和贵州遵义等5个代表性产地杜仲雄花的非靶向代谢组,利用XCMS、metaX等软件以及利用KEG...     

油茶果实主要数量性状分析及育种指标体系筛选

[目的]为更好地评价研究油茶种质资源,进一步完善油茶育种指标体系,更科学地开展优良种质筛选工作.[方法]对1361份不同种质油茶果实的11个主要数量性状进行变异分析、概率分级及相关分析.[结果]油茶果实数量性状存在丰富的变异,变化范围在14.10％ ～40.97％,其中,每500 g鲜籽数、单个鲜果质量、每果籽数、鲜果...     

基于SSR标记的杜仲群体遗传多样性及遗传结构

通过分析杜仲群体的遗传多样性水平和遗传结构,旨在为杜仲资源的管理、保护和利用提供依据。利用9对基因组SSR引物对42个杜仲群体的868份种质资源进行遗传多样性分析、群体遗传结构分析、分子方差分析和聚类分析,主要结果如下:(1)遗传多样性分析表明,42个杜仲群体的遗传多样性水平均较高;(2)遗传结构分析表明,42个群体宜分为2个类群;(3)分子方差分析和聚类分析表明,杜仲的遗传变异主要在群体内,占93%,群体间的遗传变异仅占7%,群体间遗传分化水平低,相似程度高。本研究认为:杜仲群体的遗传多样性较高;杜仲群体间的遗传分化水平低,相似程度高;杜仲的遗传变异以群体内的变异为主,保护杜仲的遗传多样性时,应保存尽可能多的种群和特异单株。     

欧洲黑杨优质核心种质库的初步构建

对159份欧洲黑杨种质资源的生长、育种值、材性、养分利用率和水分利用率等13个性状进行分析,采用13种表型选优的抽样方法构建欧洲黑杨优质核心种质库。表型值评价表明：当抽样群体比例达到21.4%以上即能满足构建核心种质要求,而只有抽样群体比例达到30.2%以上 SSR 分子遗传多样性才能满足构建核心种质要求。最终确定的欧洲黑杨优质核心种质库包含48份种质资源,占原群体的30.2%;与原群体相比,均值和方差不存在显著差异,极差符合率和变异系数变化率分别为97.07%和89.72%;优质核心种质库的有效等位基因数、Nei’s 遗传多样性系数和 Shannon’s 信息指数与原群体之间没有显著差异,保持了原群体的遗传多样性。     

不同种质杜仲叶中多酚和黄酮含量差异性分析

[目的]比较不同种质杜仲叶中多酚及黄酮含量的差异性,合理评价与利用杜仲种质资源。[方法]利用高效液相色谱法和紫外分光光度计法对105份杜仲种质叶中多酚、总黄酮、异槲皮苷及槲皮素的含量进行测定。[结果]表明:种质叶中槲皮素含量平均为0.33 mg·g-1,变异系数最大,为42.42%;总黄酮含量平均为15.92 mg·g-1,变异系数最小,为19.35%;异槲皮苷、多酚含量平均值分别为3.37、42.74 mg·g-1,变异系数分别为34.42%、23.72%。杜仲雌株和雄株叶中的多酚、总黄酮、异槲皮苷及槲皮素含量差异不著性。多酚及黄酮类物质在不同来源间均差异极显著(P0.01),其中,河北地区杜仲叶片中的总黄酮、异槲皮苷和槲皮素平均含量均最高。相关性分析发现:多酚、总黄酮、异槲皮苷含量彼此间均呈显著或极显著正相关,而槲皮素含量与多酚含量间无显著相关性。综合评价4种成分含量高低,可将杜仲种质资源分为4大类群,其中,类群Ⅲ(包括13份材料)的多酚和黄酮类活性成分含量均高于其他类群。[结论]杜仲种质叶片中多酚和总黄酮含量较高,且表现出丰富的多样性,有很大的选择和改良潜力,可为叶用杜仲资源的选育提供基础原材料。     

<Emphasis Type="Italic">Ophiostoma</Emphasis> species associated with bark beetles infesting three <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.     

Improving the evaluation of multiple-dowel-type connection strength

Our study focuses on predicting the ultimate short-term load carrying capacity of timber-to-timber connections with dowel-type fasteners. The wide range of possible configurations in practice makes the resolution of these values by tests unrealistic. Moreover, different current regulations do not consider some specific failure mechanisms. In many countries, the reduction of resistance involved by this phenomenon is taken into account by considering an effective number of dowels (n_ef) smaller than the actual number of dowels (n) in the connection. However, these different regulations disagree on the values of n_ef and on other points (spacing, partial coefficient of security, formulas). These discrepancies in design rules invite the fundamental research on this topic and, therefore, new methods are sought in order to estimate the load carrying capacities of the connections. In the light of these, our approach consists of predicting the load carrying capacity with the neural network numerical tool. The results obtained by this analysis tool are satisfactory, although the model remains complex. Subsequently, we focus on the simplification of this numerical model with classical regression techniques in order to implement it in a design code.     

Parasitic Ichneumonoidea on the horse chestnut leaf miner, Cameraria ohridella (Lepidoptera: Gracillariidae) in Slovakia

Parasitic Hymenoptera from the suprafamily Ichneumonoidea attacking the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) were studied in southwest Slovakia during 2000 and 2001. The search for such species resulted in the determination of eight ichneumonid species, Gelis agilis (Fabricius), Itoplectis alternans (Gravenhorst), I. clavicornis (Thompson), I. maculator (Fabricius), Scambus annulatus (Kiss), S. brevicornis (Gravenhorst), Zatypota percontatoria (Müller), Adelognathus sp. and a braconid Colastes braconius Haliday. The most abundant species was S. annulatus. All these species recorded are polyphagous and often facultative hyperparasitoids, except C. braconius, which departs from this norm in not being hyperparasitic. The presence of more diversified native parasitoids and hyperparasitoids from the Ichneumonoidea predicate a slow successive adaptation of the parasitoid fauna to the invasive host, Cameraria ohridella.     

Insecticidal activity of certain medicinal plants

The methanol extracts of eight species of medicinal plants were tested for insecticidal activity in third instar larvae of Egyptian cottonworm (Spodoptera littoralis). All extracts showed a certain degree of larval toxicity. The extracts of Ocimum basilicum, Origanum majorana and Salvia officinalis appeared to be highly toxic. The extracts significantly affected the growth indexes [relative growth rate (RGR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD)].     

A new norlignan from Taxodium ascendens

A new norlignan, (2R,3R,4S,5S)-2,4-bis(4-hydroxyphenyl)-3,5-dihydroxy-tetrahydropyran (1), together with 9 known compounds were isolated from the branches and leaves of Taxodium ascendens. Their structures were mainly determined on the basis of MS, IR, 1D and 2D NMR spectral evidences. Methanol extract showed inhibitory activity on carbonic anhydrase II with an IC₅₀ value of 4.27 µg/ml, acetone extract and methanol extract inhibited activity of cathepsin B with IC₅₀ values of 2.12 and 3.71 µg/ml, respectively.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

<Emphasis Type="Italic">Bursaphelenchus mucronatus</Emphasis> (Nematoda: Aphelenchoididae) vectored by <Emphasis Type="Italic">Monochamus </Emphasis><Emphasis Type="Italic">urussovi</Emphasis> (Coleoptera: Cerambycidae) in Hokkaido,Japan

Bursaphelenchus mucronatus Mamiya et Enda has been recovered for the first time from adults of the cerambycid beetle, Monochamus urussovi (Fischer), in Hokkaido, Japan. The nematode was also recovered from the inner bark of Picea jezoensis (Siebold et Zuccarini) Carrière and Abies sachalinensis (Fr Schmidt) Masters infested with M. urussovi larvae. PCR–RFLP analysis indicated that B. mucronatus in Hokkaido is the European type.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Trees and shrubs as sources of fodder in Australia

Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline.     

Rehabilitation of diseased cacao fields in Peru through shade regulation and timing of biocontrol measures

The objective of this case study was to test the effectiveness of biocontrol for the rehabilitation of abandoned, diseased (moniliasis, witches' broom and black pod) cocoa and to develop testable hypotheses regarding the effect of shade and biocontrol timing. Three trial fields differed in their shade regimes. Biocontrol was administered starting either at flowering or pod filling. Disease incidence and yield were compared with cultural control alone. Biocontrol reduced moniliasis from 49% to 25%, independent of the shading regime and application time. Witches' broom was most severe without shade and unaffected by biocontrol. No significant effects on black pod were observed. Although biocontrol increased percentage healthy fruit independent of shading and timing, only the shaded plot with biocontrol from flowering onwards responded with increased yield. Our hypothesis is: 'In the rehabilitation of abandoned cacao, only fields under sustainable shade management and early onset of biocontrol can realise their production potential.' This revised version was published online in June 2006 with corrections to the Cover Date.