Global mismatches in aboveground and belowground biodiversity

Human activities are accelerating global biodiversity change and have resulted in severely threatened ecosystem services. A large proportion of terrestrial biodiversity is harbored by soil, but soil biodiversity has been omitted from many global biodiversity assessments and conservation actions, and understanding of global patterns of soil biodiversity remains limited. In particular, the extent to which hotspots and coldspots of aboveground and soil biodiversity overlap is not clear. We examined global patterns of these overlaps by mapping indices of aboveground (mammals, birds, amphibians, vascular plants) and soil (bacteria, fungi, macrofauna) biodiversity that we created using previously published data on species richness. Areas of mismatch between aboveground and soil biodiversity covered 27% of Earth's terrestrial surface. The temperate broadleaf and mixed forests biome had the highest proportion of grid cells with high aboveground biodiversity but low soil biodiversity, whereas the boreal and tundra biomes had intermediate soil biodiversity but low aboveground biodiversity. While more data on soil biodiversity are needed, both to cover geographic gaps and to include additional taxa, our results suggest that protecting aboveground biodiversity may not sufficiently reduce threats to soil biodiversity. Given the functional importance of soil biodiversity and the role of soils in human well-being, soil biodiversity should be considered further in policy agendas and conservation actions by adapting management practices to sustain soil biodiversity and considering soil biodiversity when designing protected areas.     

Natural resistance of rose petals to microbial attack

Petals of red, yellow and white roses (Rosa damascene Mill.) of the family Rosaceae were extracted with (1:1) methylene chloride/methanol and tested for their antimicrobial activities against four species of Gram-positive bacteria (Bacillus cereus, Bacillus subtilis, Micrococcus luteus and Staphylococcus aureus), five species of Gram-negative bacteria (Enterobacter aerogenes, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and Serratia marcescens) and five species of fungi (Penicillium notatum, Aspergillus niger, Rhizopus stolonifer, Saccharomyces cerevisiae and Fusarium oxysporum). All of the crude extracts showed a wide range of antimicrobial activities according to the tested organism and rose's type. Micrococcus luteus was found to be the most susceptible bacteria to all crude extracts. Red and yellow petal extracts showed much higher antibacterial activity than the white petals extract. Bacillus subtilis was found to be the least susceptible to all extracts. The fungus, Penicillium notatum was found to be the most susceptible with white petal extract being the most effective. Saccharomyces cerevisiae and Fusarium oxysporum were the least susceptible to all extracts. White roses extract showed much higher antifungal activities against Penicillium notatum than red or yellow roses, therefore, it was subjected to several bioassay guided chromatographic fractionations and purification to isolate the active chemical(s) responsible for the antifungal activity. Chemical structure of the isolated antifungal compounds were identified by spectroscopy techniques and found to be a γ-sitosterol and (Z,Z)-9,12-octadecadienoic acid. Antibacterial activity of the various types of rose extracts were due to complex mixtures of organic compounds which are still under chemical investigation and will be published later.     

Fungitoxicity of lyophilized and spray-dried garlic extracts

Among the compounds discussed for anti-microbial and anti-fungal use allicin (allylthiosulfinate, diallyl disulfide-S-monoxide), an active ingredient of garlic, has attracted considerable attention. The objective of this study is to determine the antifungal activity of a local garlic ecotype (Voghiera) extracts against different pathogens. Primary screening was carried out by the agar plates technique using ethanol garlic extract at four final concentrations against the following organisms: Alternaria alternata, Aspergillus spp., Colletotrichum acutatum, Didymella bryoniae, Fusarium culmorum, Fusarium avenaceum, Fusarium gramineareum, Gliocladium roseum 47, Pythium splendens, Rhizoctonia solani, Sclerotium rolfsii, Stemphylium vesicarium, Trichoderma longibranchiatum, and Botrytis cinerea. Secondary screening was carried out using a lyophilized and a spray-dried preparation at different concentrations against the organisms selected for the high inhibition garlic effect in the primary screening and compared with the commercial fungicides mancozeb and iprodione. The best results were observed for the spray-dried garlic compound that showed a good fungicidal activity at the concentration of 1.5 g/10 mL while lyophilized garlic at the same concentration exhibithed less inhibition activity against the four fungi analyzed in the second screening.     

Content and bioconcentration factors of mercury by Parasol Mushroom Macrolepiota procera

The carpophores of Parasol Mushroom and underlying soil substrate collected from several unpolluted and spatially distant sites across Poland were examined to know content and bioconcentration potential of mercury by this species. The total mercury content of the caps of Parasol Mushroom for the particular sites ranged from 1.1 ± 1.0 to 8.4 ± 7.4 μ g/g dry matter (total range from 0.05 to 22 μ g/g dm), while in the stalks were from 0.53 ± 0.27 to 6.8 ± 7.1 μ g/g dm (total range from 0.078 to 20 μ g/g dm). A top soil layer (0–10 cm) showed baseline mercury concentration from 0.022 ± 0.011 to 0.36 ± 0.16 μ g/g dm (total range from 0.010 to 0.54 μg/g dm). Parasol Mushroom is an effective mercury accumulator in the carpophores and bioconcentration factor (BCF) values of this element in the caps and depending on the sampling site ranged from 16 ± 6 to 220 ± 110 (total range from 0.52 to 470), while for the stalks were from 7.6 ± 2.6 to 130 ± 96 (total range from 0.52 to 340). It seems reasonable to state that tolerance (maximum allowable concentration) of the total mercury in a single cap of Parasol Mushroom at unpolluted areas should not exceed 25 μ g/g dm. A value greater then 25 μ g/g dm will imply an elevated content due to site pollution problems. Nevertheless, knowledge on highly toxic methylmercury content and its fraction in the total mercury content of Parasol Mushroom is lacking.     

Bioconcentration potential and contamination with mercury of pantropical mushroom Macrocybe gigantea

The mushroom Macrocybe gigantea collected from the native stands in the Yunnan Province of China can be considered a species that efficiently bioconcentrates mercury (Hg) because the values of the bioconcentration factor (BCF) calculated for this element were well above unity, i.e., for caps, the BCF ranged from 4.8 to 24 and, for stipes, from 3.6 to 18. The Hg content of the composite samples of caps of the fruit bodies collected in the wild ranged from 0.48 to 1.78 mg kg^?1 dry matter and of stipes from 0.36 to 1.70 mg kg^?1 dry matter, whereas 0.37 and 0.25 mg kg^?1 dry matter were observed for farmed specimens. M. gigantea, because of a large biomass of the fruit bodies that emerge in a cluster, is an important food item in Yunnan, but knowledge on mineral composition and content of this species is largely absent. This study estimated the lifetime average daily dose intake of Hg through mushroom as well as the incremental lifetime cancer risk and non-cancer health hazard to consumers of this mushroom.     

丛枝菌根真菌对不同含盐量湿地土壤中芦苇生长的影响

采用温室盆栽实验的方法,研究接种Claroideoglomus etunicatum(CE)、Rhizophagus intraradices(RI)、Funneliformis mosseae(FM)和Glomus versiforme(GV)对非盐渍化和盐渍化湿地土壤上芦苇(Phragmites australis)菌根侵染率、生物量、矿质营养吸收、C∶N∶P生态化学计量比和Na+、Cl-含量的影响,旨在为我国湿地生态系统的生态恢复和盐碱化修复提供理论依据和技术支持.结果表明,在2种湿地土壤上4种AM真菌的平均菌根侵染率为2.5%~38%,接种CE的侵染率显著高于其它接种处理;盐渍化湿地土壤上芦苇菌根侵染率与非盐渍化湿地土壤间无显著性差异,非盐渍化湿地土壤芦苇生物量、矿质营养元素的吸收显著高于盐渍化湿地土壤,而Na+和Cl-的含量显著低于盐渍化湿地土壤.对于非盐渍化湿地土壤,接种GV处理显著增加了芦苇地上部的干重,促进了芦苇地上部对N、P、K、Ca和Mg等5种营养元素的吸收,接种GV和RI则显著促进了芦苇根部对P和K的吸收;4种接种处理显著降低了芦苇地上部N∶P,接种FM和GV显著降低了根部C∶N和C∶P;4种接种处理也显著降低了芦苇地上部Cl-的含量,接种RI处理显著降低了芦苇地上部Na+的含量.对于盐渍化湿地土壤,4种接种处理对芦苇生物量、矿质营养吸收和Na+、Cl-的含量均没有显著性影响.结果也表明,AM真菌对于不同含盐量湿地土壤芦苇生长的影响表现出不同的菌根效应,在非盐渍化湿地土壤上对芦苇生长的有益作用明显好于盐渍化湿地土壤.应结合相应的技术措施进一步通过野外实地实验筛选接种效果好的AM真菌菌种,探讨菌根技术对不同含盐量湿地土壤上芦苇生长的实际作用.     

湿生环境中丛枝菌根(AM)对香蒲耐Cd胁迫的影响

湿生植物在城市景观绿化和美化中应用越来越多,但也经常遭遇环境污染胁迫的问题.大量研究证实丛枝菌根(AM)可提高陆生植物耐受环境污染胁迫的能力,但对湿生植物的影响却鲜有认识.通过水培实验,探索接种AM真菌(Glomus etunicatum)对香蒲(Typha latifolia)耐受Cd2+(0、2.5、5.0 mg·L-1)胁迫的影响,旨在为评估菌根技术能否用于提高湿生植物抗耐环境污染胁迫的能力提供参考.结果表明,在湿生环境中AM真菌可与香蒲建立良好的共生关系,侵染率高于30%,但菌根化香蒲移入水溶液1个月后侵染率均呈下降趋势,最大下降25.5%(P0.05).AM增加了香蒲子叶的色素含量和POD酶活性,提高了根系的泌氧速率,但仅显著促进了5 mg·L-1Cd2+下香蒲的生长.虽然高浓度Cd2+抑制了香蒲的生长且侵染率下降,但AM仍能促进两个Cd2+浓度下香蒲对Cd的吸收,地上、地下部Cd含量最大增加40.24%和56.52%.本研究表明,AM具有增强湿生植物抗耐和修复环境重金属污染的潜力.     

丛枝菌根真菌(AMF)对铯胁迫宿根高粱生长及根际土壤酶的影响

通过盆栽试验研究了接种透光球囊霉(Glomus diaphanum)、摩西球囊霉(Glomus mosseae)、地表球囊霉(Glomus versiforme)及幼套球囊霉(Glomus etunicatum)等4种丛枝菌根真菌(AMF)对铯污染下宿根高粱生长及根际土壤酶活性的影响.结果表明,与未接种对照相比,接种AMF处理均显著增加了宿根高粱的株高和根长,同时增强了过氧化氢酶、蔗糖酶活性及根系活力(P0.05),且以接种G.etunicatum增强效果最好,上述酶活性和根系活力分别相当于对照的1.11、2.25和4.04倍,而接种Glomus diaphanum最显著增强了酸性磷酸酶活性,使其提高了24.53 mg·g-1·d-1·FW(P0.05),宿根高粱对铯的耐性指数均高于对照,说明AMF在一定程度上能缓解铯污染胁迫对根际土壤酶的抑制作用,进而减轻核素铯对植物的毒害;接种AMF处理显著抑制了脲酶活性,表明脲酶可作为反应土壤核素铯污染的一个有效指标.同时也表明AMF有效地增强了宿根高粱对核素铯的耐性能力.     

Molecular diversity of arbuscular mycorrhizal fungi at a large-scale antimony mining area in southern China

Arbuscular mycorrhizal fungi(AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony(Sb). The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE). Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis(PCA) indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis(RDA) showed that Sb contamination was the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.     

接种丛枝菌根真菌对蜈蚣草吸收铀的影响

采用盆栽土壤实验,模拟铀(uranium,U)污染土壤,以蜈蚣草(Pteris vittata L.)为研究材料,每盆接种丛枝菌根真菌地表球囊霉(Glomus versiforme,Gv)30 g,探索蜈蚣草菌根对U污染土壤不同时间段的修复效果.结果表明,蜈蚣草菌根侵染率2013年9月最低为57.14%,2014年3月最高为75.20%,呈先上升后下降的年周期变化规律;同一时期蜈蚣草的生物量(干重)Gv组显著高于CK组,根系最为明显;接种Gv组蜈蚣草各器官总U含量均显著高于CK组,且被吸收的U主要固定在根部,Gv组根部总U含量均高于同一时期CK组;接种Gv组基质中总U含量小于CK组,其中接种Gv后蜈蚣草对铁锰氧化态和硫化物态U的吸收效果最好;基质中各形态U随培养时间的延长含量均呈下降趋势.接种Gv组比CK组富集系数大,且均大于1;菌根侵染率与富集系数呈显著正相关关系.以上结果说明接种Gv促进蜈蚣草对U的吸收,因此,蜈蚣草丛枝菌根真菌共生体对治理U污染土壤有良好的应用前景.