The influence of diets containing dried bivalve feces and/or powdered algae on growth and energy distribution in sea cucumber Apostichopus japonicus (Selenka) (Echinodermata : Holothuroidea)

In recent years, bivalve feces and powdered algae have been used as the food sources of holothurians in China. In this study, growth and energy budget for sea cucumber Apostichopus japonicus (Selenka) with initial wet body,veights of 32.5 1.0 g (mean +/- SE, n=45) when fed with five different granule diets containing dried bivalve feces and/or powdered algae in water temperature 13.2-19.8 degrees C and salinity 30-32ppt were quantified in order to investigate how diets influence growth and energy distribution and to find out the proper diet for land-based intensive culture of this species. Results showed that diets affected the food ingestion, feces production, food conversion efficiency and apparent digestive ratios, hence the growth and energy budget. Sea cucumbers fed with dried feces of bivalve showed poorer energy absorption, assimilation and growth than individuals fed with other four diets; this could be because feces-drying process removed much of the benefits. Dried bivalve feces alone, therefore, were not a suitable diet for sea cucumbers in intensive cultivation. The mixed diets of feces and powered algae showed promising results for cultivation of sub-adult Apostichopus japonicus, while animals fed with powdered algae alone, could not obtain the best growth. According to SGR of tested animals, a formula of 75% feces and 25% powdered algae is the best diet for culture of this species. Extruded diets were used in the present experiment to overcome shortcomings of the traditional powdered feeds, however, it seems a conflict exists between drying bivalve feces to form extruded diets and feeding sea cucumbers with fresh feces which contain beneficial bacteria. Compared with other echinoderms, in holothurians the energy deposited in growth is lower and the energy loss in feces accounts for the majority of the ingested energy. Such detailed information could be helpful in further development of more appropriate diets for culture of holothurians. (c) 2006 Elsevier B.V. All rights reserved.

The effect of the causative algae of large-scale HAB in the East China Sea on egg hatching of Argopecten irradians, and population growth of Brachionus plicatilis and Moina mongolica

The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monoculture and mixture of the two species were examined on the egg-hatching success of Argopecten irradians Lamarck, and the population growth of Brachionus plicatilis Muller and Moina mongolica Daday. The results showed that monoculture of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities ( EDSo) inhibiting the egg hatching success of A. irradians for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm(3), respectively. Monoculture of P. donghaiense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis (1 x 10(4) similar to 3 x 10(4)cells/cm(3)) and M. mongolica (2 x 10(4) similar to 5 x 10(4) cells/cm(3)); P. doaghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis (4 x 10(4) similar to 10 x 10(4) cells/cm(3)) and M. mongolica (10 x 10(4) cells/cm(3)). When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.

Biosorption of Cr(VI) from aqueous solutions by nonliving green algae Cladophora albida

Biosorption of Cr(VI) from aqueous solutions by nonliving green algae Cladophora albida was investigated in batch experiments. The influence of pH, algal dosage, initial Cr(VI) concentration, temperature and coexisting anions on removal efficiencies of C. albida was studied. Cr(VI) removal process was influenced significantly by the variation of pH, and the optimum pH was chosen at a range of 1.0-3.0. The optimum algal dosage 2 g/L was used in the experiment. The removal rate of Cr(VI) was relatively rapid in the first 60 min, but then the rate decreased gradually. Removal mechanism was studied by analyzing Cr(VI) and total Cr in the solution. Biosorption and bioreduction were involved in the Cr(VI) removal. Biosorption of Cr(VI) was the first step. followed by Cr(VI) bioreduction and Cr(III) biosorption on the algal biomass. Actual industrial wastewater was used to evaluate the practicality of the biomass C. albida. From a practical viewpoint, the abundant and economic biomass C. albida could be used for removal of Cr(VI) from wastewater by the reduction of toxic Cr(VI) to less toxic Cr(III). (C) 2008 Elsevier Ltd. All rights reserved.

Screening marine algae from China for their antitumor activities

Thirty-nine species of marine algae collected from the coast of China were screened for their antitumor activities, and eight species Leathesia difformes, Polysiphonia urcedata, Scytosiphon lomentarius, Gloiopeliis furcata, Punctaria latifolia, Symphyocladia latiuscula, Rhodomela confervoides and Ulva pertusa showed potent cytotoxic activities. Three, Rhodomela confervoides, Scytosiphon lomentarius and Gloiopeliis furcata, were used for further investigation. More than 30 compounds were isolated and purified, and 14 bromophenols, 1 steroid and 1 carotene were identified by advanced spectroscopic methods including IR, MS, and NMR techniques. Amongst the 16 identified compounds, 7 showed vigorously selective activities against KB, Bel7402 and A549 cancer cells, and 6 bromophenols were new compounds.

Fatty acids of some algae from the Bohai Sea

The fatty acid compositions of 22 species of marine macrophytes, belonging to the Ceramiales, Cryptonemiales, Nemalionales, Laminariales, Chordariales, Scytosiphonales, Desmarestiales, Dictyosiphonales, Fucales, Dictyotales and Ulvales and collected from the Bohai Sea, were determined by capillary gas chromatography. The contents of polyunsaturated fatty acids (FAs) in the Bohai Sea algae, in comparison with the same species from the Yellow Sea were found to be lower. Red algae had relatively high levels of the acids 16:0, 18:1(n-7), 18:1(n-9), 20:5(n-3) and 20:4(n-6), and those examined were rich in C-20 PUFAs, these chiefly being arachidonic and eicosapentaenoic acids. The major FAs encountered in the Phaeophyta were 14:0, 16:0, 18:1(n-9), 18:2(n-6), 18:3(n-3), 18:4(n-3), 20:4(n-6) and 20:5(n-3). C18PUFAs are of greater abundance in the brown algae than in the red algae examined. All three green algae from the Ulvales had similar fatty acid patterns with major components, 16:0, 16:4(n-3), 18:1(n-7), 18:2(n-6), 18:3(n-3), and 18:4(n-3). They contained 16:3(n-3) and more 16:4(n-3), were rich in C18PUFAs, chiefly 18:3(n-3) and 18:4(n-3) and had 18:1(n-7)/18:1 (n-9) ratios higher than 1. (C) 2002 Elsevier Science Ltd. All rights reserved.

Sorption and desorption of lead (II) from wastewater by green algae Cladophora fascicularis

Biosorption is an effective method to remove heavy metals from wastewater. In this work, adsorption features of Cladophora fascicularis were investigated as a function of time, initial pH, initial Pb(II) concentrations, temperature and co-existing ions. Kinetics and equilibria were obtained from batch experiments. The biosorption kinetics followed the pseudo-second order model. Adsorption equilibria were well described by the Langmuir and Freundlich isotherm models. The maximum adsorption capacity was 198.5 mg/g at 298 K and pH 5.0. The adsorption processes were endothermic and the biosorption heat was 29.6 kJ/mol. Desorption experiments indicated that 0.01 mol/L Na(2)EDTA was an efficient desorbent for the recovery of Pb(II) from biomass. IR spectrum analysis suggested amido or hydroxy, C=O and C-O could combine intensively with Pb(II). (C) 2006 Elsevier B.V. All rights reserved.

Biosorption of copper (II) and lead (II) from aqueous solutions by nonliving green algae Cladophora fascicularis: Equilibrium, kinetics and environmental effects

Biosorption of Cu2+ and Pb2+ by Cladophora fascicularis was investigated as a function of initial pH, initial heavy metal concentrations, temperature and other co-existing ions. Adsorption equilibriums were well described by Langmuir and Freundlich isotherm models. The maximum adsorption capacities were 1.61 mmol/ g for Cu2+ and 0.96 mmol/ g for Pb2+ at 298K and pH 5.0. The adsorption processes were endothermic and biosorption heats calculated by the Langmuir constant b were 39.0 and 29.6 kJ/ mol for Cu2+ and Pb2+, respectively. The biosorption kinetics followed the pseudo- second order model. No significant effect on the uptake of Cu2+ and Pb2+ by co-existing cations and anions was observed, except EDTA. Desorption experiments indicated that Na(2)EDTA was an efficient desorbent for the recovery of Cu2+ and Pb2+ from biomass. The results showed that Cladophora fascicularis was an effective and economical biosorbent material for the removal and recovery of heavy metal ions from wastewater.

Extraction of the polysaccharides from five algae and their potential antioxidant activity in vitro

The sulfated polysaccharides extracted from algae possess excellent antioxidant activities. In this study, we prepared five polysaccharides extracted from five algae including one brown alga Laminaria japonica. one red alga Porphyra haitanensis and three green algae Ulva pertusa, Enteromorpha linza and Bryopsis plumose. And then the antioxidant activities of all the samples were investigated including scavenging effects of superoxide and hydroxyl radicals, and reducing power. The chemical analysis and FT-IR spectrum showed these extracts were polysaccharides. And in addition, we found that certain polysaccharide exhibited stronger antioxidant activity in certain antioxidant activity. Factors effecting and attributing to radical scavenging effect need to be further studied. (C) 2010 Elsevier Ltd. All rights reserved.

根瘤菌、铵态氮、光照强度对大豆固氮和光合作用影响的研究

生物固氮和植物光合作用作为全球生态系统的两个基本生物学过程, 在碳氮循环、自然生态系统的维持和演替，以及农业生产中起了重要作用。尽管过去关于共生固氮与光合作用的研究取得了巨大成就，但是，很少将两者直接联系起来。本研究通过比较低光效和高光效大豆接种高效固氮根瘤菌后固氮与光合作用的差异，比较接种根瘤菌和施用铵态氮肥对大豆光合生理的影响或光照强度对大豆光合固氮的影响，以及C4基因转化C3 豆科植物—苜蓿的研究，试图将两者偶联起来。研究获得以下结果： 1．用nifA和dct工程根瘤菌接种低光效和高光效大豆后，与出发菌株比，均提高了大豆的固氮和光合作用。两者相比，nifA工程菌对低光效大豆黑农37号发挥了比较好的作用，大豆的光合作用参数，固氮活性和植物株高、株重等产量参数比dct工程菌好;dct工程菌接种高光效大豆黑农40号后，尽管固氮酶活性与nifA工程菌相比没有明显差异，但是大豆光合作用和产量参数有了比较明显的提高。 2．光照培养条件下，对大豆进行了接种根瘤菌（108细菌/ mL）、低氮（5 mmol/L (NH4)2SO4）和高氮（30 mmol/L (NH4)2SO4）处理。测定的大豆生长状况和光合作用系列参数结果表明：低氮处理的最好，接种根瘤菌的次之，高氮处理的最差。由此说明单纯接种根瘤菌满足不了大豆发育过程中的氮营养要求，其光合作用和生长受到不利影响。但是，高氮处理也并没有提高大豆的光合作用，其生长发育甚至受到抑制。该结果为生产实践中合理施肥提供了光合生理方面的参考。 3．接根瘤菌和不接根瘤菌的大豆在正常光强（150μmol photons m-2s-1）下生长三周后进行遮光（15μmol photons m-2s-1，7天）和复光（正常光强，7天）处理，大豆的光合作用有下降和回复。测定的一系列光合参数、叶绿素荧光参数，以及植物的生长生理参数结果表明：接根瘤菌大豆与不接根瘤菌的大豆对遮光的响应有不同。正常光照下，接种根瘤菌能促进大豆生长与光合作用;遮光处理后，根瘤菌对大豆的促进作用不显著。 4．获得了不同苜蓿品种的愈伤组织及其诱导的再生植株。并作了用小米、甘蔗的PEPC基因转化苜蓿的研究。由于在实验过程中，考虑转基因植物的安全性，着重于用甘露糖筛选转化体系的研究工作，忽略了用抗生素筛选转化体。用PCR法从苜蓿中扩增出甘露糖异构酶基因（pmi），表明苜蓿体内含有自己的甘露糖异构酶基因，使得甘露糖筛选没有成功。

植物个体的生理生态动力学模型

GCTE（全球变化和陆地生态系统），作为IGBP的核心计划之一，其目的是研究陆地生态系统与全球气候变化及人类社会经济和土地利用改变之间相互作用的耦合机理关系，预测生态系统结构、功能的未来变化。其中，植物个体水平的生理生态学模型研究是GCTE中必不可少的重要环节，它不仅可以揭示植物在个体水平上对全球变化的动态响应机制，而且可通过揭示大尺度响应所隐含的微观生物学机理，为大尺度研究提供重要的生理学参数和规律，在全球变化各尺度研究中发挥着不可替代的作用。本文主要围绕植物个体的生理生态学模型开展了如下研究：在开顶式气室CO2倍增大豆生长实验基础上，建立描述植物主要生理过程的生理生态模型，分析植物个体的光合作用、气孔传导度、蒸腾作用以及水分利用效率在全球场变化下的动态响应机制;在此基础上，建立起以统计性天气模型驱动的植物个体生长发育系统动力学模型，通过敏感度分析探讨植物个体的生理生态特性，如光合、呼吸、绿色及非绿色生物量等，对全球变化，特别是对CO2增加，气温升高及降水改变共同作用的响应机制;针对固氮植物的特点，将前一模型发展成为基于共生固氮和同化过程相互作用机制的植物个体生理生态系统动力学模型，模拟不同CO2浓度、气候变化以及固氮与不固氮条件下植物个体生物量的动态响应，并分析CO2浓度、气候条件和是否具固氮能力在对植物生长发育影响方面的相互作用;以中间锦鸡儿为研究材料进行水分控制实验，观测水分对植物同化物分配等过程的影响;将水分利用效率模型应用到NECT样带的主要植物种，得出各植物种的描述其水分利用效率特性的参数，结合样带上各植被类型的结构特征，得到沿样带各植被类型在植物种类组成方面的水分利用效率参数;应用系统聚类分析、因子分析等多元统计方法对样带上锡林河流域122种植物的化学成分与植物类群和所处生境的关系进行了定量分析。结果表明： 1）CO2倍增情况下，净光合速率提高45%，其中光量子效率显著增加，而CO2传导系数略有下降;气孔传导度、蒸腾速率下降约30%;水分利用效率随CO2浓度增加几乎呈线性增长，倍增后提高近一倍。（当气温，水分适宜，光合有效辐射为1000μmol photons m-2 s-1); 2）在北京地区仅CO2倍增而气候条件维持现状的情况下可导致大豆总生物量峰值提高70%，绿色部分提高56%，其中，全生育期内总净光合量增加，而单位干重的暗呼吸速率下降;由于受同化物分配中物候因素的影响，绿色生物量比总生物量提前10日左右到达其峰值。 3）CO2浓度增加和具固氮能力在模拟范围内对植物生长均产生正效应;而在水分为植物生长限制因子的干旱半干旱地区，降水增加对植物生长产生正效应，气温升高则具负效应; 4）随着C供给条件的好转，具固氮能力对植物生长的影响增强;反之随植物吸收N能力的提高，C供给对植物生长的作用加剧。 5）气温、降水在对植物生长发育影响方面，随着一方条件的好转，另一方对植物生长产生的效应增强; 6）具固氮能力对植物生长的正效应随气候条件的好转而增强，气候变化对植物生长的影响随植物具备了固氮能力而加剧; 7）气候条件越恶劣，如在此半干旱区变得更为干旱，CO2浓度增加对植物生长的正效应越加显著;且随CO2浓度的增加，气候因子的效应逐渐减弱。这主要是因CO2增加提高了植物个体的水分利用效率，从而使得CO2的正效应在水分胁迫下更为明显;同时由于水分利用效率的提高，使得植物个体抵御和适应外界环境变化，特别是由气温、降水改变导致的水分条件变化，的能力得到增强。 8）锦鸡儿水分生理生态实验的初步结果表明，土壤水分状况影响着植物的同化物分配，随着水分胁迫的加剧，同化物分配向根部集中，植物的根冠比增加。 9）沿样带水分递减梯度，植被类型在植物种类组成方面的反映水分利用效率特性的参数kv逐渐增加，从而显示出随着水分条件的不足，植被类型中耐旱品种，尤其是C4种增加;人为活动干扰，主要是对草场等的过度利用而导致的盐渍化、沙化，使得退化了的植被类型中k_v值显著提高，表明原有的植物种逐渐被耐旱、耐盐碱的品种，特别是C4植物所代替;在样带动上，这种由于人为活动干扰所引起的植被类型在植物种类组成方面反映水分利用效率特性的参数kv的变化明显大于因样带水分梯度改变而带来的变化。 10）锡林河流域草原植物化学成分一方面与植物类群有关，受自身历史演化的决定，另一方面更受到所处生境条件的极度大影响和制约。其中，禾本科、豆科植物分别具有明显的化学成分特征;撂荒地群落与自然群落中植物、沙质与非沙质生境中植物化学成分差异较显著;因子分析中认为存在大量元素与微量元素两个公共因子，豆科与禾本科相比，豆科植物因其固氮能力，所含大量元素水平较高，而禾本科植物因细胞壁硅质化，含微量元素稍高;沙质生境因其养分贫瘠，植物的大量与微量元素均较非沙质生境中的低;特别是本区地带性土壤-栗钙土与特异性生境沙带中的疏林沙土相比，疏林沙土上植物大量与微量元素含量较栗钙土区植物明显偏低。

内蒙古草原地耳和发菜的固氮特性及在氮素循环中的作用

以内蒙古干旱半干旱草原上的固氮蓝藻－普通念珠藻和发状念珠藻为研究对象，对其分布、生态特点、形态结构、生物量及不同条件下的固氮活性进行了研究，并根据降水与气温状况对其年固氮量进行了估算。结果表明：同发状念珠藻相比，普通念珠藻的分布更为广泛，其形态也有较大的差异。普通念珠藻的生物量在以禾本科为主的退化草场和沙地上较大，在pH值偏碱、含水量300％和温度30℃的情况下，其固氮活性较高，达2500nmolC2H2/g•h（干重）以上，年固氮量也高达4.19kg/h.m2，占草原氮素总输出的10％左右。由此可见，在维持干旱半干旱草原与荒漠草原生态系统的氮素平衡中，固氮蓝藻这类低等固氮植物可能起着重要作用。

北京东灵山暖温带典型植被类型物种构成及物种多样性对氮素转化过程的影响

通过调查东灵山地区7个典型植被类型的物种多样性，并测定各林型中植物叶片养分特征，凋落物品质，土壤理化特性，豆科植物的生物固氮作用以及土壤有机质的净N矿化与硝化作用，研究了不同林型及其物种多样性对氮素转化过程的可能影响。结果表明： 1) 各林型乔灌草三层13个物种多样性指数之间都不同程度存在差异，且都表现基本一致的大小顺序，各样地乔灌草三层3个丰富度指数和5个多样性指数之间大都表现草本层>灌木层>乔木层的大小顺序。 2) 林型对植物叶片养分特征、叶片凋落物品质指标、土壤的大多数理化特性都有显著影响，其中，落叶阔叶林与针叶林之间的差异最为明显，优势种不同的针叶林之间也不同程度地存在差异。各林型物种多样性对植物叶片养分特征，凋落物品质和土壤理化特性也都不同程度存在显著影响，且乔灌草三层的物种多样性的影响不同。我们的结果支持物种多样性对生态系统过程存在显著影响的观点。 3) 胡枝子(Lespedeza bicolor)％FNDA值较低，在0～53.3％之间，与国外学者对某些木本豆科固氮植物的研究结果接近，但低于三叶草、野豌豆等草本豆科固氮植物。胡枝子生物固氮具有明显的季节差异，不同样地生境对胡枝子％FNDA值也存在显著影响，大都都表现铁塔辽东栎样地>重力点样地>站下灌丛样地>垭口样地的趋势。除胡枝子之外的其他豆科植物的％FNDA都高于胡枝子，且存在种间差异，以三籽两型豆(Amphicarpaea capillipes)最高(100％)，歪头菜(Vicia unijuga)最低(平均66.4％)，这些结果与国外相关研究接近。不同林型之间和同一林型不同样地之间也影响豆科植物的％FNDA。东灵山地区有相当数量的植物种具有和固氮植物相近的δ15N值和全N含量，具有潜在的生物固氮能力。6个林型中所有豆科植物的％FNDA平均值主要受乔木层和草本层物种多样性的影响，乔木层和草本层物种多样性提高，豆科植物的％FNDA将随之显著降低。 4) 气温、土壤温度和降水量显著影响各林型净氮硝化速率的季节动态，都表现为温度升高，降水量增加，净氮硝化速率也随之增大。 5) 在不同取样时间，不同林型在土壤NH4+、N03-含量，矿化、硝化速率以及年度总净矿化、硝化量之间均不同程度存在显著差异，其中，以辽东栎落叶阔叶林与针叶林之间，常绿针叶林与落叶针叶林之间，纯林与混交林之间的差异最为明显。 6) 土壤初始N0_3含量与年度总净硝化量，年度总净矿化量及其占TKN的百分比呈显著正相关关系;植物叶片全N浓度与净氮矿化、硝化作用呈显著负相关：植物叶片凋落物的品质指标与净氮矿化、硝化作用没有显著相关。 7) 胡枝子固氮作用(％FNDA值)越强，土壤有机氮的净硝化量就越大，胡枝子在从大气中获取大量N，的同时，很可能会增加氮素的淋溶损失量。胡枝子固氮作用(％FNDA值)与净氮矿化量不存在显著相关关系。 8) 只有乔木层和草本层部分种多样性指数对净氮矿化、硝化量存在显著影响。乔木层均匀度提高，土壤净氮碳化量将随之增大;而草本层物种多样性提高，均匀度提高，净氮矿化、硝化作用将随之降低，草本层植物对土壤氮素矿化作用具有显著抑制作用。 9) 落叶阔叶林与针叶林的供氮能力和维持无机氮素的能力之间存在比较明显的差异，而不同针叶林的矿化／硝化作用也有所差别。其中，辽东栎落叶阔叶林的供氮能力和维持氮素能力均高于针叶林和山杏灌丛;油松林的供氮能力与防止氮素损失的能力显然要强于落叶松林和山杏灌丛。 10) 尽管箭叶锦鸡儿灌丛植物叶片与凋落物中全N、全P浓度在大多数取样点上都低于硕桦(高于草甸)，但表层土中全N浓度高于硕桦和草甸，且其土壤有机质的供氮能力以及维持氮素能力都高于硕桦林和草甸，表明，锦鸡儿灌丛为侵入草甸和硕桦入侵提供了良好的养分条件，在该演替序列的发展过程中起了一定的推动作用。

库布齐沙地三年生人工藻结皮发育特征及微生物分布

对库布齐沙地4种三年生不同立地条件下人工藻结皮的发育特征和微生物分布进行研究,结果表明:(1)将荒漠蓝藻接种到沙面,形成的人工藻结皮经过3年的生长和发育,结皮的平均厚度达到2.23—5.36mm,呈现深黑色和灰绿色,结皮盖度大于70%。其中沙柳(Salixcheilophila Schneid.)-羊草(Aneurolepidium chinensis)-藻(algae)结皮(SAA)发育最好、生物量最高,且演替成苔藓结皮。在人工藻结皮区普遍出现沙生植物的拓殖和大量生长,如沙米(Agriphyllum s