4种湿地植物混合群落净化污染水体的试验

湿地生态系统中的植物群落物种组成对水体的自然净化效果具有重要的影响。文中以广西桂林会仙湿地4种植物[苦草(Vallisneria natans)、芦苇(Phragmites australis)、华克拉莎(Cladium chinense)、美人蕉(Canna indica)]构建表面流湿地系统,进行生活污水污染水体的净化效果研究,同时,以会仙湿地污染严重水域(七星码头)生长的植物[菹草(Potamogeton crispus)、黑藻(Hydrilla verticillata)、凤眼莲(Eichhornia crassipes)、芦苇]构建对照系统进行对比分析。结果表明:苦草组(苦草+芦苇+华克拉莎+美人蕉)及菹草组(菹草+黑藻+凤眼莲+芦苇)对污染水体中TP、TN和COD_(Mn)均有明显净化效果。苦草组对TP、TN、COD_(Mn)的去除率分别为54.26%~85.25%、53.80%~83.64%、36.27%~73.62%;菹草组对TP、TN、COD_(Mn)的去除率分别为49.14%~63.81%、45.77%~60.81%、30.25%~52.26%。苦草组具有更高的水体净化能力,经处理后TP、TN、COD_(Mn)的平均出水质量浓度分为0.07、0.76、9.41 mg/L。2组植物群落系统对TP、TN、COD_(Mn)的去除效果均表现为夏、秋季高于冬、春季。将苦草、芦苇、华克拉莎、美人蕉组成的植物混合群落移植到会仙湿地污染严重水域进行原位强化修复,具有较强的可行性。

山东盐碱地棉田不同杂草群落对棉花产量影响研究

于2011和2012连续2年在山东省高唐县盐碱地棉田中人为设置无草区、禾本科杂草、阔叶杂草以及混合杂草自然发生区,研究了不同杂草群落危害对棉花产量的影响。结果表明,禾本科杂草区以牛筋草、狗尾草、芦苇等为主,2年总密度分别为202.0和291.6茎/m2,棉花产量损失为24.3%和20.3%;阔叶类杂草区以藜、马齿苋、鳢肠等为主,2年总密度分别为230.5和122.2茎/m2,产量损失为27.1%和60.2%;混合杂草区2011年以藜、牛筋草、稗草为主,2012年以藜占绝对优势,其次为马齿苋、牛筋草等,总密度分别为277.0和201.0茎/m2,产量损失为37.5%和68.4%。综合2年试验结果,在盐碱地环境中,阔叶杂草对棉花的单茎损失率大于禾本科杂草;杂草危害造成棉花的产量损失表现在直接影响棉花的产量构成因素,其中对棉花成铃数的影响最大,杂草混合生长区成铃数2年比无草区分别减少34.0%和72.0%,阔叶杂草和禾本科杂草生长区可减少10.8%～53.6%;另外,杂草危害可使棉花株高降低0.4%～18.7%,棉花果枝数降低11.9%～18.0%,棉花单铃重减少6.3%～18.2%;棉花的保苗率减低0～3.6%。杂草对棉花产量影响程度大小与田间杂草种类、密度、生长量以及棉花品种的生物学特性密切相关,温度和降水等气候因素对盐碱地杂草群落组成以及杂草与棉花之间的竞争性关系也有较大影响。

High efficient mixed culture screening and selected microbial community shift for bioleaching process

To screen the high efficient mixed culture and understand the bioleaching behaviors of mixed culture for low-grade copper sulfide ore bioleaching,ten mixed cultures were collected and screened from different acid mine drainages obtained from sulfide mines of China.The leaching rate was set as criterion to screen the mixed culture and the metagenomic approach.Community genome array（CGA） was used for analyzing the mixed culture microbial community shift during the bioleaching process.The results indicate that the mixed culture obtained from Yinshan（YS） lead-zinc mine in Dexing of Jiangxi province in China reaches the maximum copper extraction（68.89%） during the one bioleaching period of 24 d.CGA results show that YS culture contains nine kinds of bacteria which are belong to six divisions,and the microbial community structure is changing during the bioleaching process.This provides a good way to accelerate the bioleaching process and reveals the microbial community shift during the bioleaching process.

湿热地区轻薄绿色屋顶不同种植基质中植被生长表现绩效研究

立足于重庆为代表的亚热带湿热气候条件,聚焦轻薄绿色屋顶景观,采用分区条形重复随机实验设计,构建具有2种混合草本群落、4种轻质保水基质类型,基质深度为20cm的绿色屋顶模块实验平台,对不同基质中植被生长高度、地面覆盖度、存活率、视觉外观指数、叶片气孔导度等指标以及基质体积水分含量进行持续监测,第一个生长季研究结果表明:综合各项生长表现指标,斑叶芒、花叶芒、细叶芒、阔叶山麦冬、紫竹梅、蓝花鼠尾草在轻薄绿色屋顶设施中表现优异,具有细密颗粒配比的轻质保水型D类基质在轻薄绿色屋顶的草本植被群落上具有应用优势,对重庆及亚热带湿热气候条件下轻薄绿色屋顶的景观构建具有基础研究意义与应用价值。

Comparative study on chalcopyrite bioleaching with assistance of different carbon materials by mixed moderate thermophiles

The catalysis of four carbon materials including artificial graphite(AG), carbon black(CB), activated carbon(AC) and carbon nanotube(CN) on chalcopyrite bioleaching by mixed moderate thermophiles was comparatively investigated. In AC and AG added bioleaching groups, low solution pH and suitable redox potential values, high total iron and ferric iron concentrations, and large number of adsorbed bacteria were obtained, resulting in high copper extractions. CB and CN inhibited the growth of bioleaching bacteria and led to the low bioleaching efficiency.X-ray diffraction analysis showed that jarosite and sulfur film were the main components of passivation layer with the addition of AG and AC,but did not hinder the dissolution of chalcopyrite. Microbial community structures of free and attached cells in AC and AG added groups changed dramatically compared with mixed moderate thermophiles. The sulfur-oxidizing bacteria of A. caldus S1 strain dominated the microbial community(93%-98%) at the end of bioleaching.The iron-oxidizing bacteria of L.ferriphilum YSK only accounted for low percentage(1%-2%).

4种挺水植物、4种沉水植物及其组合群落去除模拟富营养化水体中总氮和总磷的作用比较

在模拟的不同水体富营养化条件下,研究了分别由4种挺水植物[雨久花(Monochoria korsakowii)、黄花鸢尾(Iris wilsonii)、泽泻(Alis maplantago-aquatica)和野慈姑(Sagittaria trifolia)]、4种沉水植物[狐尾藻(Myriophyllum verticillatum)、黑藻(Hydrilla verticillata)、金鱼藻(Ceratophyllum demersum)和竹叶眼子菜(Potamogeton malaianus)]组成的群落以及由以上随机2种挺水植物+2种沉水植物组成的混合群落对水体中总氮和总磷的去除作用,旨在明确与单由挺水植物或沉水植物组成的群落相比,由挺水植物与沉水植物混合组成的群落是否对水体中的总氮和总磷具有更强的去除能力,并探讨其去除总氮、总磷的增强作用是否受水体富营养化水平的影响。在实验开始和结束时,分别测定了植物、底泥和水体中的总(全)氮和总(全)磷含量以及植物群落的总生物量。研究结果表明,混合群落中黑藻、金鱼藻、雨久花和黄花鸢尾的相对生长速率和累积生物量显著高于它们在单由挺(沉)水植物组成的群落中的相对生长速率和累积生物量,相应地,混合群落中的黒藻、雨久花和黄花鸢尾的全氮和全磷积累率也显著高于单由挺(沉)水植物组成的群落;与单由挺(沉)水植物组成的群落相比,混合群落具有较高的水体总磷去除率,且随着水体富营养化程度的加重而增大,然而其对水体总氮去除率与单由挺(沉)水植物组成的群落差异不显著;在水体中、高富营养化水平下,混合群落底泥的全氮去除率和全磷积累率显著高于单由挺(沉)水植物组成的群落;在水体不同的富营养化水平下,在所构建的混合群落中,狐尾藻+黒藻+雨久花+黄花鸢尾群落、黑藻+金鱼藻+雨久花+野慈姑群落和黑藻+竹叶眼子菜+泽泻+野慈姑群落群落都表现出较高的水体总氮和总磷去除率。因此,与单由挺(沉)水植物植物组成的群落相比,混合群落生长和生态功能都具有一定的增强效应,且该效应受水体富营养化水平的显著影响。

Assessing Conservation Values of Forest Communities in Nanda Devi Biosphere Reserve: Plant Diversity, Species Distribution and Endemicity

Present study has been conducted in a biodiversity rich Nanda Devi Biosphere Reserve between 2000-3800 m in two different forest physiognomy holding sites to analyze the structure and composition of the forest communities including richness of native, non native and endemic species,and suggest conservation values at community and reserve level.A total of 60 sites were sampled and grouped in 11 and 8 communities for two representative sites Pindari-Sunderdhunga-Kafni(PSK) and Lata-Tolma-Phagti(LTP) respectively.From the sampled sites, 451 species(11.8%, 53 trees;17.71%, 80 shrubs; and 70.51%, 318 herbs) have been recorded.In general, PSK site represented 73.6% and LTP site represented only 54.9% of the total plant species recorded in the study area.Out of total species in PSK site, native species contributed 59.6%(198spp.) and 24.7% species were endemic and near endemic.In LTP site, 66.5% species were Himalayan natives and 33.5% were endemic and near endemic.The species richness ranged from 4-23 ind ha-1(tree),3-18 ind ha-1(sapling), 5-19 ind ha-1(seedling) in PSK site and 4-18 ind ha-1(tree), 4-11 ind ha-1(sapling), 4-16 ind ha-1(seedling) in LTP site.The density ranged from 260-535 ind ha-1(tree), 145-633 ind ha-1(sapling), 1450-8170 ind ha-1(seedling) in PSK site and 599-1211 ind ha-1(tree), 70-951 ind ha-1(sapling),470-1665 ind ha-1(seedling) in LTP site.Species diversity for trees ranged from 0.73-3.37, saplings,0.64-2.67, seedlings, 0.70-2.51, shrubs, 1-2.34 and herbs, 2.02-3.21 in PSK site and 0.63-1.61, saplings,0.76-1.36, seedlings, 0.35-1.79, shrubs, 0.98-2.73 and herbs, 2.48-3.61 in LTP site.These recorded values were almost comparable with the studies conducted in sub-tropical, temperate and sub-alpine regions of the west Himalaya.In some cases the values were slightly higher than the reported values.The important communities with high conservation values have been identified based on different ecological parameters and species distribution.Among all the prioritized communities, Mixed Silver firRhododendron-Maple community in PSK site and Taxus wallichana- A.pindrow mixed community in LTP site supports maximum richness and density of native and endemic species.This study calls for development of adequate strategy and action plan for the conservation and management of habitats, species,and communities under changing climate and socioeconomic scenarios, so that sustainable utilization of the species could be ensured.

氯化钠对乳酸合成己酸效能及功能微生物群落的影响

探究己酸功能菌群对NaCl的耐受浓度,以及在不同NaCl浓度条件下的己酸合成效能,为评估餐厨垃圾转化为己酸的潜力提供参考.为探究己酸功能菌群对NaCl的耐受浓度,以及在不同NaCl浓度条件下的己酸合成效能,从而为评估餐厨垃圾转化为己酸的潜力提供参考.通过批式试验研究不同浓度的NaCl(0、2、6、10、20和30 g/L)对以梭菌属第四族(Clostridium IV)为核心的混合菌群发酵乳酸合成己酸的效能以及群落结构的影响.结果表明,随着NaCl浓度从2-10 g/L的升高,己酸合成效能呈下降趋势,而短链脂肪酸(乙酸、丙酸、丁酸和戊酸)的浓度呈上升趋势;当NaCl浓度达到20 g/L时,己酸合成停止,丙酸、丁酸和戊酸成为主要产物;当NaCl浓度达到30 g/L时,丙酸成为最主要的产物,细胞浓度和总ATP浓度显著下降.对己酸发酵菌群的多样性分析结果表明,当NaCl浓度提高至10 g/L时,在系统分类的属水平上,与产己酸相关的Clostridium IV在整个菌群中的相对丰度由47.78%(空白)下降至35.06%(10 g/L),而另一种可能与产己酸相关的菌Pseudoramibacter比例则由0.04%上升至0.17%.NaCl浓度达到30 g/L时,与丙酸合成相关的菌Propionibacterium的相对丰度从0.006%(空白)上升至0.09%.本研究表明,对于乳酸合成己酸系统来说,NaCl是一种不利的影响因素,当NaCl浓度在6 g/L及以下时,己酸菌可以保持其功能,即将乳酸主要转化为己酸;当NaCl浓度提高至10 g/L及以上时,己酸合成受到抑制;结果可为羧酸平台技术应用于餐厨垃圾处理的实际工程提供科学依据和理论支撑.(图6表1参53)

花粉记录的青藏高原中部中全新世以来植被与环境

青藏高原中部的草甸/草原混合生态群落,对气候变化非常敏感.孢粉记录显示草原发育时期,莎草减少,区域气候是相对干旱的,在时间上对应季风相对弱的时期.依据唐古拉山垭口湖、阿洪错和错那3个淡水湖泊钻孔孢粉分析,定量重建的温度和降水指标,探讨该地区8200 cal a BP以来的植被与气候变化.8200～6500 cal a BP,尤其是8200～7200 cal a BP,植被以草甸/草原混合生态群落为主,显示强季风控制着青藏高原中部;6000～4900,4400～3900以及2800～2400 cal a BP时期区域植被以草原植被为主,应是3次百年尺度的干旱事件;4900～4400 cal a BP期间植被类型由草原向草甸转变;6500～5400和3000～1600 cal a BP出现两次大的变干事件;数值摸拟估计,高原中部接近于现今的环境,最早可能出现在6500cal a BP,自3000cal a BP以后高原中部季风性降水和湿度逐渐减少至现今水平,可能在700～300cal a BP出现一次小冰期变冷事件.

Characteristics of fungal community structure during the decomposition of mixed foliage litter from Pinus massoniana and broadleaved tree species in southwestern China

Aims The conifer litter is fairly recalcitrant and nutrient poor,and broadleaved litter promotes coniferous litter decomposition by increasing degradable nutrients and promoting microbial metabolism.Mixing Pinus massoniana litter and three broadleaved litters may increase the diversity and abundance of fungal decomposers compared with those in P.massoniana litter and vary depending on the number and proportion of broadleaved species included.Methods We analysed the composition and diversity of fungal communities during mixed litter decomposition in southwestern China with 35 treatments(P.massoniana,Toona sinensis,Cinnamomum camphora and Sassafras tzumu litter)using Illumina high-throughput sequencing.Important Findings The mixed litters increased fungal diversity and richness compared with those in the single-species litter,except in the following treatments:P.massoniana litter accounting for 70%-80%in the P.massoniana+T.sinensis,P.massoniana+S.tzumu+T.sinensis and P.massoniana+S.tzumu+C.camphora combinations,and P.massoniana+S.tzumu+C.camphora+T.sinensis combination with small proportion of T.sinensis litter.The diversity and richness of the 7:1:2 combination of P.massoniana+C.camphora+T.sinensis were significantly higher than those in the other treatments.Ascomycota and Basidiomycota were the dominant phyla,and Aspergillus was the most abundant genus.The decomposition of litters from one needleleaf and one broadleaved species(6:4)and one needleleaf species and two broadleaved species(broadleaved litter accounting for 30%-40%)exhibited synergistic interactions throughout the decomposition process,and the relative abundance of fungi that decompose refractory substances increased.The P.massoniana+C.camphora+T.sinensis combination and a 30%-40%broadleaf litter proportion increased fungal diversity and accelerated the decomposition of recalcitrant coniferous litter.Therefore,C.camphora and T.sinensis are a potential candidate species for mixed planting with P.massoniana.

Illumina-Based Analysis of Bulk and Rhizosphere Soil Bacterial Communities in Paddy Fields Under Mixed Heavy Metal Contamination

There is an increasing concern about rice （Oryza sativa L.） soil microbiomes under the influence of mixed heavy metal contamina- tion. We used the high-throughput Illumina MiSeq sequencing approach to explore the bacterial diversity and community composition of soils in four paddy fields, exhibiting four degrees of mixed heavy metal （Cd, Pb and Zn） pollution, and examined the effects of these metals on the bacterial communities. Our results showed that up to 2 104 to 4 359 bacterial operational taxonomic units （OTUs） were found in the bulk and rhizosphere soils of the paddy fields, with the dominant bacterial phyla （greater than 1% of the overall community） including Proteobacteria, Actinobacteria, Firmicutes, Acidobacteria, Gemmatimonadetes, Chlorofiexi, Bacteroidetes and Nitrospirem. A number of rare and candidate bacterial groups were also detected, and Saprospirales, HOC36, SC-I-84 and Anaerospora were rarely detected in rice paddy soils. Venn diagram analysis showed that 174 bacterial OTUs were shared among the bulk soils with four pollution degrees. Rice rhizosphere soils displayed higher bacterial diversity indices （ACE and Chao 1） and more unique OTUs than bulk soils. Total Cd and Zn in the soils were significantly negatively correlated with ACE and Chao 1, respectively, and the Mantel test suggested that total Pb, total Zn, pH, total nitrogen and total phosphorus significantly affected the community structure. Overall, these results provided baseline data for the bacterial communities in bulk and rhizosphere soils of paddy fields contaminated with mixed heavy metals.