闽江口芦苇与短叶茳芏空间扩展对湿地土壤磷赋存形态的影响

选择闽江口鳝鱼滩的芦苇湿地、短叶茳芏湿地以及芦苇与短叶茳芏空间扩展形成的交错带湿地为对象，研究了不同湿地土壤磷赋存形态的分布特征及其主要影响因素。结果表明，不同湿地土壤中各形态磷含量整体表现为HCl-Pi > NaOH-Pi > Residual-P > NaHCO₃-Pi > NaOH-Po > Sonic-Pi > Resin-Pi > NaHCO₃-Po。其中，难分解态磷占TP的比例最高（Resin-Pi、NaHCO₃-Pi、NaHCO₃-Po），为48.3%-51.1%；中等易分解态磷次之（NaOH-Pi、NaOH-Po、Sonic-Pi、Sonic-Po），为37.4%-38.8%；而易分解态磷最低（HCl-P、Residual-P），为11.5%-12.9%。交错带湿地土壤中易分解态磷、中等易分解态磷和难分解态磷含量相对于纯群落湿地均发生了明显改变，其值相比芦苇湿地分别提高了10.6%、19.2%和22.6%，相比短叶茳芏湿地分别提高了1.6%、11.5%和16.6%，原因主要与二者空间扩展过程中交错带湿地土壤的理化性质特别是粒度组成、pH以及Fe、Al含量均较纯群落湿地发生明显改变有关。芦苇与短叶茳芏的空间扩展整体改变了湿地土壤的全磷（TP）含量和储量，相对于芦苇湿地和短叶茳芏湿地，交错带湿地土壤的TP含量分别增加了20.0%和7.1%，而磷储量分别增加了12.0%和18.0%。研究发现，芦苇与短叶茳芏的空间扩展不但改变了湿地土壤中磷的赋存状况，而且亦可能改变不同磷形态之间的转化。交错带湿地土壤磷赋存状况有助于缓解芦苇与短叶茳芏空间扩展过程中对磷养分的竞争压力，从而可能在一定程度上维持交错带湿地系统的相对稳定。     

Nutrient release from swamp water,Cyperus papyrus L. organs and swamp sediments

Nitrogen and phosphorus releases from swamp water,Cyperus papyrus plant organs and papyrus swamp sediments were investigated over five weeks. The release of nutrients by dissolution of decomposing organic matter was very important for the swamp water under the prevailing anaerobic conditions. Large amounts of nutrients were found in the incubation water with plant organs and sediments within the first 48 hours. Leaching of the nutrients from the plant organs and sediment caused high initial values. Subsequently decomposition of the organic material caused slight changes in the nutrient levels in the water. Probably denitrification played a role in the nitrogen dynamics, while phosphorus was mineralized.     

Agricultural encroachment: implications for carbon sequestration in tropical African wetlands

Tropical wetlands have been shown to exhibit high rates of net primary productivity and may therefore play an important role in global climate change mitigation through carbon assimilation and sequestration. Many permanently flooded areas of tropical East Africa are dominated by the highly productive C₄ emergent macrophyte sedge, Cyperus papyrus L. (papyrus). However, increasing population densities around wetland margins in East Africa are reducing the extent of papyrus coverage due to the planting of subsistence crops such as Colocasia esculenta (cocoyam). In this paper, we assess the impact of this land use change on the carbon cycle and in particular the impacts of land conversion on net ecosystem carbon dioxide exchange. Eddy covariance techniques were used, on a campaign basis, to measure fluxes of carbon dioxide over both papyrus and cocoyam dominated wetlands located on the Ugandan shore of Lake Victoria. Peak rates of net photosynthetic CO₂ assimilation, derived from monthly diurnal averages of net ecosystem exchange, of 28–35 μmol CO₂ m^?2 s^?1 and 15–20 μmol CO₂ m^?2 s^?1 were recorded in the papyrus and cocoyam wetlands, respectively, whereas night‐time respiratory losses ranged between 10 and 15 μmol CO₂ m^?2 s^?1 at the papyrus wetland and 5–10 μmol CO₂ m^?2 s^?1 at the cocoyam site. The integration of the flux data suggests that papyrus wetlands have the potential to act as a sink for significant amounts of carbon, in the region of 10 t C ha^?1 yr^?1. The cocoyam vegetation assimilated ~7 t C ha^?1 yr^?1 but when carbon exports from crop biomass removal were accounted for these wetlands represent a significant net loss of carbon of similar magnitude. The development of sustainable wetland management strategies are therefore required to promote the dual wetland function of crop production and the mitigation of greenhouse gas emissions especially under future climate change scenarios.     

Effects of rhizosphere remediation and bioaugmentation on carbofuran removal from soil

Rhizosphere soil contains important sources of nutrients for microorganisms resulting in high number of microorganisms capable of degrading various types of chemicals in the soil. Thus, this study investigated a carbofuran dissipation in rhizosphere soils of 6 weeds namely, umbrella sedge (Cyperus iria L.), fuzzy flatsedge (C. pilosus V.), small flower umbrella plant (C. difformis L.), tall-fringe-rush hoorah grass (Fimbristylis miliacea V.), cover fern (Marsilea crenata P.), and water primrose (Jussiaea linifolia V.). Rhizosphere soil of fuzzy flatsedge showed the shortest half-life (t_1/2) of carbofuran (15 days) among other soils. So, it was selected to be used in the bioaugmentation experiment using carbofuran degrader namely Burkholderia cepacia, PCL3, as inoculum in order to examine whether they would improve carbofuran degradation in soil. The results showed that the addition of PCL3 into rhizosphere soil did not improve carbofuran degradation suggesting that microorganisms in rhizosphere soil might be capable enough to remove carbofuran from soil. The number of carbofuran degraders in the rhizosphere soils was greater than in bulk soil 10–100 times which might be responsible to a rapid degradation of carbofuran in rhizosphere soils without the addition of PCL3. The ability of PCL3 to degrade carbofuran was evident in bulk soil (t_1/2 of 12 days) and autoclaved soils (t_1/2 13–14 days) when compared to soils without an inoculation (t_1/2 of 58 days) indicated that the addition of a degrader was useful in improving carbofuran degradation in soil.     

山东莎草属植物果实形状及果皮微形态研究

利用扫描电镜对山东分布的18种莎草属植物的果实形状及果皮微形态进行了观察研究。结果表明,莎草属植物果实为椭圆状、倒卵状或卵状三棱形,顶端具柱状或锥状短喙;果皮微形态可分为:网-疣复合纹饰、网状纹饰、疣状纹饰和无规则突起纹饰4种类型;果皮微形态类型的划分与基于宏观形态特征的传统分类关联较小,但在该属形态相近的种间存在明显差异,可作为种间划分的依据。果皮微形态证据支持将水莎草属(Juncellus)、砖子苗属(Mariscus)和断节莎属(Torulinium)归入莎草属(Cyperus)的分类观点。     

闽江河口区淡水和半咸水潮汐沼泽湿地土壤产甲烷菌多样性

为认识盐度对河口潮汐沼泽湿地土壤产甲烷菌的影响,应用PCR-RFLP技术及测序分析对闽江河口区淡水-半咸水盐度梯度上分布的4个短叶茳芏潮汐沼泽湿地土壤产甲烷菌群落结构进行研究。闽江河口区短叶茳芏潮汐沼泽湿地土壤产甲烷菌群落结构受盐度影响明显,位于下洋洲和塔礁洲的短叶茳芏潮汐淡水沼泽湿地土壤产甲烷菌的香农-威纳多样性指数值分别为2.81和2.65,位于蝙蝠洲和鳝鱼滩的短叶茳芏潮汐半咸水沼泽湿地土壤产甲烷菌香农-威纳多样性指数值分别仅为2.33和2.27。系统发育分析表明:短叶茳芏沼泽湿地土壤产甲烷菌类群主要有甲烷杆菌目(Methanobacteriales),包括Methanobacterium、Methanobrevibacter和Methanobacteriaceae;甲烷微菌目(Methanomicrobiales),主要有Methanoregula,以及甲烷八叠球菌目(Methanosarcinales),主要有Methanosarcina和Methanococcoides。闽江河口区短叶茳芏潮汐淡水沼泽湿地土壤主要的优势产甲烷菌有Methanoregula、Methanosarcina和Methanobacterium,而短叶茳芏潮汐半咸水沼泽湿地土壤主要的优势产甲烷菌则转化为仅以Methanoregula为主。     

Relationship correlation of antioxidant and antiproliferative capacity of Cyperus rotundus products towards K562 erythroleukemia cells

A Total Oligomers Flavonoids (TOFs) and ethyl acetate extracts of Cyperus rotundus were analyzed, in vitro, for their antioxidant activity using several biochemical assays: the xanthine (X)/xanthine oxidase (XO), the lipid peroxidation induced by H₂O₂ in K562 human chronic myelogenous leukemia cells and the DNA damage in pKS plasmid DNA assay induced by H₂O₂/UV-photolysis and for their apoptotic effect. TOF and ethyl acetate extracts were found to be efficient in inhibiting xanthine oxidase with IC₅₀ values of 240 and 185 μg/ml and superoxide anion with IC₅₀ values of 150 and 215 μg/ml, respectively. Also, all the extracts tested were effective in reducing the production of thiobarbituric acid reactive substances (TBARS) and were able to protect against H₂O₂/UV-photolysis induced DNA damage. The highest activity, measured as equivalents of MDA concentration, was observed in the ethyl acetate extract (MDA = 2.04 nM). In addition, the data suggest that only TOF enriched extract exerts growth inhibition on K562 cells through apoptosis induction. Therefore, these extracts were subjected to further separation by chromatographic methods. Thus, three major compounds (catechin, afzelechin and galloyl quinic acid) were isolated from the TOF enriched extract and five major compounds (luteolin, ferulic acid, quercetin, 3-hydroxy, 4-methoxy-benzoic acid and 6,7-dimethoxycoumarin) from ethyl acetate extract. Their structures were determined by spectroscopic data analysis and comparison with the literature. In addition, we evaluate the biological activities of the catechin, ferulic acid and luteolin. This investigation has revealed that the luteolin was the most active in reducing the production of TBARS (MDA = 1.5 nM), inhibiting significantly the proliferation of K562 cells (IC₅₀ = 25 μg/ml) and protecting against H₂O₂/UV-photolysis induced DNA damage. In conclusion, the study reveals that the ability of C. rotundus to inhibit the enzyme xanthine oxidase (XO), the lipid peroxidation and to exert apoptotic effect, may explain possible mechanisms by which C. rotundus exhibits its health benefits.     

风车草和香根草在人工湿地中迁移养分能力的比较研究

为研究风车草（Cyperus alternifolius）和香根草（Vetiveria zizanioides）迁移养分的能力,建立17.0 m²风车草潜流式人工湿地和13.3 m²香根草潜流式人工湿地处理猪场废水,在四个季节末测定植物生物量和组织氮、磷、铜、锌含量.结果表明,香根草地下部生物量大于风车草,地上部生物量则是风车草大于香根草.风车草年地上部收获量为3406.47 g·m^-2,比香根草的1483.88 g·m^-2高2.3倍;风车草的氮含量为22.69 mg·g^-1,比香根草的15.44 mg·g^-1高7.25 mg·g^-1;风车草的磷含量为6.09 mg·g^-1,比香根草的5.47 mg·g^-1高0.62 mg·g^-1.植株含铜、锌量风车草略比香根草高.风车草每年迁移N 68.72 g·m^-2和P 18.49 g·m^-2,香根草迁移N 8.93 g·m^-2和P 3.69 g·m^-2.风车草人工湿地每年由植物迁移的氮、磷、铜、锌比香根草高4～7倍.