车桑子大孢子发生与雌配子体发育

采用常规石蜡切片法,对车桑子大孢子的发生和雌配子体的发育进行观察,探讨车桑子自然结籽率低的原因和明确其胚胎发育特征。结果表明:(1)车桑子花柱有花柱道,子房3室,中轴胎座,横生胚珠,每心室两枚胚珠,双珠被,厚珠心,无承珠盘。(2)位于珠心表皮细胞下的孢原细胞经平周分裂产生造孢细胞,造孢细胞发育为大孢子母细胞,大孢子母细胞经减数分裂形成线性四分体,靠近珠孔端3个大孢子退化消失,靠合点端大孢子发育为功能大孢子,大孢子发生类型为单孢子发生型。(3)单核胚囊经3次有丝分裂形成7细胞8核的成熟胚囊,胚囊发育类型为蓼型。(4)花器官形态的变化和大孢子发育过程有一定联系,可根据雌花形态特征大致判断大孢子发育时期。研究认为,车桑子雌配子体发育过程中出现的胚囊不中空、游离核不进一步细胞化等异常现象,可能是导致车桑子自然结籽率低的原因之一。     

First Report of Phytophthora Foliar Blight on Florida Hopbush (Dodonaea viscosa) in Italy

During 2010, a new foliar blight was detected on potted Dodonaea viscosa cv. Purpurea plants in two nurseries in Catania (Italy). On the basis of morphological and cultural features, the pathogen was identified as Phytophthora palmivora. The internal transcribed spacer (ITS)‐rDNA sequence of a representative Phytophthora isolate from hopbush showed 99% identity with other ITS sequences of different P. palmivora isolates available in GenBank, thus confirming the morpho‐cultural identification. Koch’s postulates were fulfilled by pathogenicity tests on potted D. viscosa cv. Purpurea seedlings. To our knowledge, this is the first report of P. palmivora foliar blight disease on D. viscosa.     

Effects of microorganism on carbon,nitrogen and phosphorus of Dodonaea viscosa and the soils from different elevations in Yuanmou,Yunnan, China

Aims Understanding the effects of soil microorganism at different elevations on plant C:N:P stoichiometry can help us to understand the plant-soil interactions in the context of climate change. Our aim was to quantify the independent and interactive effects of soil microbial communities and temperatures on the C, N, and P in the leaves of Dodonaea viscosa—a global widespread species. Methods Rhizosphere soils of D. viscosa were collected from two elevation zones in Yuanmou County, Yunnan Province. A 2 × 3 factorial experiment with six replications was conducted using climate chambers. The leaf C, N and P contents and the soil properties were measured after three months of the treatments. Important findings Compared with the autoclaved treatment, inoculated rhizosphere soils from both high and low elevations had higher nutrient absorption, especially P uptake. Temperature produced no significant effect on leaf C:N:P stoichiometry, but the interactive effect of temperature and microbial treatment appeared significant. For inoculated rhizosphere soils from high elevation, temperature had no significant effect on leaf C:N:P stoichiometry. For inoculated rhizosphere soils from low elevation, leaf N and P contents under low temperature were significantly lower than those with warmer soils. The promoting effect of soil microorganisms on nutrient uptake may be due to the direct effect of beneficial microorganisms (e.g., mycorrhizal fungi), but not through the alteration of nutrient cycling process. Because D. viscosa in the inoculated rhizosphere soils absorbed more N and P from the soil than those in autoclaved soil, the available N and P in inoculated rhizosphere soils were lower than those in autoclaved soils. As predicted future temperature will be lower in the studied region, the growth of D. viscosa may be negatively affected through plant-microbe feedbacks.     

Phytochemical,acaricidal and biological activity of Dodonaea viscosa L. against the two spotted spider mite Tetranychus urticae Koch

Alcohol extract, saponins and flavones fractionated from Dodonaea viscosa leaves were tested for their acaricidal activity against the adult females of Tetranychus urticae Koch. It was found that crude alcohol extract was more potent than the isolates obtained. At LC₅₀ and LC₉₀ levels, the crude extract ranked the first. All the biotic factors are significantly affected. The fecundity was seriously reduced however, the hatchability of eggs was not affected. Two flavonoids were identified as Querectin 3–0-glucose 7-0-rhamnoside and the other as Querectin 3-0 arabinose 7-0 rhammoside from the ethyl acetate fraction of the alcohol extract.     

干旱胁迫对坡柳等抗旱树种幼苗膜脂过氧化及保护酶活性的影响

以金沙江干热河谷主要树种坡柳、银合欢、山毛豆实生幼苗为材料,通过盆栽苗自然干旱胁迫,同时以浇水处理为对照,研究了干旱胁迫对坡柳、银合欢、山毛豆3个树种丙二醛含量、膜相对透性及保护酶活性的影响。结果表明,干旱胁迫下3个树种幼苗的细胞膜透性、MDA及SOD, POD酶活性都发生了变化,只是变化的幅度和进程不同。干旱胁迫对银合欢膜系统损伤生成的主要降解产物不是MDA;山毛豆清除活性氧毒害作用主要不是通过SOD和POD的作用;通过叶片相对保水力测定及膜透性、MDA相对含量、酶活性变化情况的分析,3个树种中坡柳耐旱性最强,其次为银合欢,山毛豆居后。     

A species well travelled – the Dodonaea viscosa (Sapindaceae) complex based on phylogenetic analyses of nuclear ribosomal ITS and ETSf sequences

Aim To determine the evolutionary history of the widely studied, cosmopolitan polymorphic species Dodonaea viscosa (hop bush, varnish tree). Location All continents except Antarctica, extending from 44° S (in the South Island of New Zealand) to 33° N (in California and Arizona). Methods For 50 samples across the worldwide distribution, Bayesian analyses of nuclear ribosomal transcribed spacers (ITS 1, ITS 2 and partial ETS) were performed. The alignment was partitioned by secondary structure and analysed using separate models of sequence evolution for each spacer’s stem and loop partition. Bayesian relaxed‐clock estimations of divergence times were used to investigate the tempo of the transoceanic dispersal history of Dodonaea viscosa. Results The widely distributed Dodonaea viscosa evolved in Australia from its most recent common ancestor in the Late Pliocene to Early Pleistocene and subsequently split into two distinct, geographically based, intraspecific lineages. There are a number of regional subclades that are also supported by specific molecular elements. Main conclusions Dodonaea viscosa is not an old lineage, as has often been speculated based primarily on its vast distribution. It diverged from its most recent common ancestor and subsequently dispersed and established around the world within the last 2 Myr. Two distinct lineages within Dodonaea viscosa, which have been shaped by Quaternary climatic change, have separate dispersal histories. The molecular investigations have identified that, although there are least two evolutionary lineages within the complex, they do not correlate with any distinct morphological subunits. It is proposed that Dodonaea viscosa (including D. biloba and D. procumbens) be recognized as an ochlospecies.     

Effect of the saprophytic fungus Fusarium oxysporum on arbuscular mycorrhizal colonization and growth of plants in greenhouse and field trials

Effects of the saprophytic fungus Fusarium oxysporum on arbuscular mycorrhizal (AM) colonization and plant dry matter were studied in greenhouse and field experiments. Host plants: maize (Zea mays L.), sorghum (Sorghum vulgare L.), lettuce (Lactuca sativa L.), tomato (Lycopersicum esculentum L.), wheat (Triticum vulgare L), lentil (Ervum lens L.) and pea (Pisum sativum L.), the AM fungi: Glomus mosseae, G. fasciculatum, G. intraradices, G. clarum, and G. deserticola and the carriers for F. oxysporum inoculum: aqueous solution, thin agar slices, and pellets of agar and alginate were tested under greenhouse conditions. Greatest plant growth and AM colonization responses in sterilized and unsterilized soils were observed with pea, Glomus deserticola and sodium alginate pellets as the carrier for F. oxysporum inoculum. Under field conditions, adding F. oxysporum increased the survival of transplanted pea, possibly through a beneficial effect on AM fungi. Application of F. oxysporum increased shoot dry matter, N and P concentrations of pea and sorghum plants, and the level of AM colonization attained by indigenous or introduced AM fungi. These parameters were similar in plants inoculated with either G. deserticola or with the indigenous AM fungi. Application of the saprophytic fungus increased the number of propagules of AM fungi in field plots in which pea was grown, but this increase was not sufficient to increase AM colonization of sorghum after the pea crop. This revised version was published online in June 2006 with corrections to the Cover Date.     

模拟铅污染土壤中杂草的菌根形成及对铅的吸收

通过盆栽试验研究了13种杂草在模拟铅污染土壤中的菌根形成及对铅的吸收累积特点。结果表明铅污染对杂草的生长没有明显影响。铅污染土壤中杂草的菌根侵染状况发生了显著变化,与无污染的土壤相比,苦荬菜(Ixerischinensis)、早熟禾(Poaannua)、黑麦草(Loliumperenne)、野燕麦(Avenafatua)、野豌豆(Viciacracca)、白车轴草(Trifoliumrepens)的菌根侵染率下降,而无芒稗(Echinochloacrusgallivar.mitis)、北美车前(Plantagovirginica)、鼠曲草(Gnaphaliumaffine)和酢浆草(Oxaliscorniculata)的菌根侵染率上升,鸡眼草(Kummerowiastriata)、升马唐(Digitariaciliaris)和婆婆纳(Veronicadidyma)无明显变化;土壤中的孢子数除了鸡眼草、野豌豆、白车轴草和酢浆草无显著差异外,其余物种在铅污染土壤中的孢子数量与对照相比明显下降。不同的杂草物种对土壤铅的吸收和积累存在明显差异,被杂草吸收的铅主要积累在杂草根系内,向杂草地上部转移的铅比率不高。     

铅与镉在被金鱼吸收积累过程中的相互作用

采用混合体系暴露和顺次暴露的方法研究了铅和镉在被金鱼吸收过程中的相互作用.结果表明,混合暴露条件下,保持镉暴露量不变,增加铅的投放量,鳃镉与肝镉含量与单独暴露的结果无显著性差异,肾镉含量则随铅暴露浓度增加而减少.保持铅浓度不变,增加镉的投放量可导致鳃和肾铅含量下降.在镉、铅顺序暴露后则没有观测到鳃、肝和肾铅含量的规律性变化.     

产喜树碱内生真菌的筛选及鉴定

从喜树Camptotheca acuminate树皮和果实中分离得到27株内生真菌,发酵后经HPLC检测,筛选出一株菌丝产喜树碱的菌,产量达774μg/L。对其ITS序列进行系统发育分析,结合其培养特征和显微特征,鉴定为拟茎点霉属(Phomopsis sp.)。这是首次报道分离自喜树的该属真菌发酵产喜树碱。     

耐铅镉菌株的分离鉴定及其吸附能力

堆肥中添加生物钝化剂是当前降低粪便中重金属生物毒性最为有效的方式之一,为了进一步提高其钝化重金属的能力,文中获得了复合重金属高耐性的钝化剂菌株,并探究其生物学特性和吸附特征。采集猪粪堆肥样品并在改良的牛肉膏培养基中分离和筛选耐铅又耐镉的高耐性菌株,通过形态结合分子生物学鉴定该菌株。该菌株分别在不同pH、温度和盐浓度条件下培养获得其最适的生长条件,进而在该条件下分析其对铅镉吸附的特性。结果获得一株耐铅浓度为600 mg/L、镉浓度为120 mg/L的铅镉复合耐性菌株SC19,该菌株为西地西菌属,其最适生长环境为pH值7.0、温度37℃、盐浓度0.5%。培养36 h的稳定期SC19菌株在吸附时间30min时铅的去除率最高,对铅的最大去除率和吸附量分别为60.7%和329.13mg/g;培养8h的对数期在吸附时间30min时镉的去除率最高,对镉的最大去除率和吸附量分别为51.0%和126.19 mg/g。红外光谱分析显示,SC19菌株对铅镉离子的吸附主要是细胞表面的多种活性基团与金属离子发生络合作用。该研究揭示了SC19菌株有较好的二价态铅镉离子吸附能力,可为生物钝化重金属提供重要的微生物种...     

纳米氧化锌和接种丛枝菌根真菌对大豆生长及营养吸收的影响

纳米氧化锌是应用最广的人工纳米颗粒(nanoparticles,NPs)之一,具有一定生物毒性。丛枝菌根(arbuscular mycorrhizal,AM)真菌能与陆地上80%以上的高等植物形成丛枝菌根共生体,并能改善宿主植物矿质营养,提高其抗逆性。然而纳米ZnO与丛枝菌根的关系尚不清楚。通过温室沙培盆栽试验,研究了施加不同水平纳米ZnO(0、500、1000、2000、3000 mg/kg)和接种AM真菌Acaulospora mellea对大豆生长及营养状况的影响。结果表明,3000 mg/kg的纳米ZnO显著抑制大豆植株生长,表现出植物毒性,在其他水平时没有显著影响。纳米ZnO在施加水平500、1000 mg/kg时没有抑制AM真菌对大豆根系的侵染,但是高施加水平(2000 mg/kg)时对AM真菌产生毒害,几乎完全抑制大豆根系菌根侵染。接种AM真菌仅在500 mg/kg纳米ZnO时显著促进大豆生长,增加大豆植株对P、K、N的吸收,降低根系Zn含量。纳米ZnO可能会持续释放锌离子,并抑制大豆根系对矿质营养元素的吸收,从而产生生物毒性,而AM真菌与大豆根系的共生可起到有益作用。     

The effect of copper on the growth of wood-rotting fungi and a blue-stain fungus

The effect of copper (II) ions on the growth of three brown-rot fungi, six white-rot fungi and one blue-stain fungus in solid medium was evaluated. The fungi were grown in malt extract agar with different concentrations of copper added, and the radial growth rate was determined. At the end of the incubation period, the mycelial biomass and the media pH were determined. The white-rot and blue-stain fungus grew up to 3 mM and 6 mM copper, respectively and the brown-rot fungi were the only ones that grew up to 10 mM, with higher growth rates than those shown by the other fungi. In general, the brown-rot fungi produced greater acidification in the culture media than the white-rot fungi and blue-stain fungus, and the acidification increased when the amount of copper was increased. The biomass production for the different species, in the absence or presence of copper, was not related to the radial growth rate, and the fungal species that produced the greatest biomass amounts did not correspond to those that presented the highest growth rates. The brown-rot fungi Wolfiporia cocos and Laetiporus sulfureus and blue-stain fungus Ophiostoma sp. demonstrated greater tolerance to high copper concentrations in solid medium than the white-rot fungi, determined as radial growth rate. On the other hand, the highest biomass producers in solid medium with copper added were the white-rot fungi Ganoderma australe and Trametes versicolor and the brown-rot fungus Gloeophyllum trabeum.     

Effects of seed burial on germination,protein mobilisation and seedling survival in Dodonaea viscosa

Ecological restoration of disturbed areas requires substantial knowledge of the germination of native plants and the creation of novel methods to increase seedling establishment in the field. We studied the effects of soil matrix priming on the germination of Dodonaea viscosa seeds, which exhibit physical dormancy. To this end, we buried both pre‐scarified (in H₂SO₄, 3 min) and non‐pre‐scarified seeds in the Parque Ecológico de la Ciudad de México. After seeds were unearthed, they were post‐scarified for 0, 2, 6 and 10 min and their germination percentages compared to the germination of a control batch of laboratory‐stored seeds. For both control and unearthed seeds, the protein pattern was determined in the enriched storage protein fraction in SDS‐PAGE gels stained with Coomassie blue. Percentage germination increased as the scarification time increased. Pre‐scarification significantly increased percentage germination of post‐scarified seeds in relation to the control and non‐pre‐scarified seeds. In seeds unearthed from the forest site, the buried pre‐scarified seeds had relatively high percentage germination, even in the absence of post‐scarification treatment. A 48‐kDa protein was not found in unearthed, pre‐scarified seeds nor in the control germinated seeds, indicating that mobilisation of this protein occurred during soil priming. Burying seeds for a short period, including the beginning of the rainy season, promoted natural priming, which increased protein mobilisation. Functionally, priming effects were reflected in high percentage seedling survival in both the shade house and the field. Seed burial also reduced the requirement for acidic post‐scarification.     

一株产紫杉醇菌的分离及其代谢产物对HeLa细胞抑制作用的研究

从东北红豆杉Taxus cuspidata的主干和侧枝树皮及皮下分离筛选得到181株纯化的内生菌株。经过摇瓶发酵培养,再用甲醇、乙酸乙酯萃取抽提,抽提产物经以标准紫杉醇为对照的薄层层析(TLC)、高效液相色谱(HPLC)、质谱(MS)分析,发现有1株菌株HD181-23能够产生紫杉醇,其紫杉醇产量为206.34μg/L。对菌株HD181-23菌落、菌丝体和孢子形态和产孢特征进行了研究,表明菌株HD181-23为葡萄孢属的种,暂定为Botrytissp.。该菌株的发酵提取纯化产物经HeLa细胞毒实验,结果显示对HeLa细胞具有较强的抑制作用。     

硅对土壤-烟草系统中铅迁移及形态分布的影响

通过盆栽试验,以烟草为对象,研究了硅对土壤 烟草系统中铅的迁移以及土壤、烟草中铅形态分布的影响.结果表明： 施硅使非根际土壤可交换态铅向铁锰氧化物结合态转化,使根际土中交换态铅向铁锰氧化物结合态和残渣态转化,降低了土壤中铅的植物有效性与迁移性.施硅显著提高了烟草根部和叶部的生物量,显著降低了烟草铅的总吸收量和烟草各器官的铅含量,其中烟草铅的总吸收量降低了6.5%～44.0%,烟叶铅含量降低了3.1%～60.4%.施硅使烟草根、茎和叶中乙醇提取态、去离子水提取态和氯化钠提取态向盐酸提取态和残渣态转化,降低了烟草体内铅的毒性与迁移性.土壤-烟草系统中土壤向烟草根部的移动指数和根部向茎部的移动指数随施硅量的增加而降低,烟草茎部向叶部的移动指数随着施硅量的增加呈先增高后降低的趋势.硅通过降低土壤铅有效性、缓解铅对烟草的毒害、改变烟草体内铅的形态分布,进而抑制土壤中铅向烟草叶部的迁移,降低烟叶中的铅含量.施硅是降低土壤铅的迁移性及烟叶铅含量的有效措施.     

Effect of entomopoxvirus infection of the smaller tea tortrix, Adoxophyes sp. on the development of the endoparasitoid, Ascogaster reticulatus

Infection of Adoxophyes sp. (Lepidoptera: Tortricidae) larvae by an entomopoxvirus (AsEPV) adversely affected the development of the endoparasitoid, Ascogaster reticulatus Watanabe (Hymenoptera: Braconidae). Parasitoid larvae developing in AsEPV-infected hosts grew more slowly and spent more time in their hosts than did parasitoid larvae developing in noninfected hosts. Percentages of emergence of larval parasitoids that developed in AsEPV-infected hosts were significantly lower than those of parasitoids that developed in noninfected hosts. Parasitoid larvae in AsEPV-infected host perished when their hosts died of AsEPV infection. Significant numbers of parasitized and infected larvae exhibited apolysis to the final instar, whereas noninfected-parasitized larvae died in the penultimate instars due to emergence of parasitoids.     

一株耐铅镉真菌的分离鉴定及其吸附特性的研究

【目的】以扎龙湿地污染的土壤为材料,进行耐铅镉菌株的分离鉴定,研究不同条件对菌株吸附铅镉的影响。【方法】采用平板划线法,逐级驯化,筛选出一株耐铅镉菌株,通过生理生化特征及ITS序列分析对菌株进行鉴定,探究该菌吸附的最佳条件,并进行Langmuir和Freundlich等温吸附模型拟合。【结果】本研究分离得到一株菌株JB15,最高耐受浓度为Pb²⁺1200 mg/L、Cd²⁺200 mg/L,经鉴定为球孢白僵菌,最佳吸附条件温度为30°C,pH为7.0,接菌量为8.0 g/L,吸附时间为60 min,铅镉吸附率分别为52.27%和62.38%;铅镉吸附量分别为19.60 mg/g和3.98 mg/g,符合Langmuir等温吸附模型。【结论】菌株JB15具有较好的吸附效果,可为微生物修复重金属土壤污染提供理论基础。