沉水植物中挥发性物质对铜绿微囊藻的化感作用

比较了两种淡水沉水植物金鱼藻和苦草中挥发性物质对铜绿微囊藻的化感抑制作用,在100mg／L浓度下,新鲜植物挥发油的抑藻作用非常显著,两种植物抑藻活性相近,但是在干粉材料中金鱼藻挥发油的抑藻活性明显强于苦草,且挥发油浓度与抑藻活性呈正相关。不同植物之间以及新鲜植物和植物干粉之间挥发油的成分和相对含量差别较大,新鲜植物挥发油中含有40％的邻苯二甲酸酯,而在于粉挥发油中70％为脂肪族化合物和萜类物质。在新鲜植物挥发油中约占20％的是不稳定的未知物,其化学结构和生物活性有待进一步研究。     

Allelopathic activity of volatile substance from submerged macrophytes on Microcystin aeruginosa

Considerable attention has been paid on the allelopathic potential of aquatic macrophytes against blue-green algae. This study compared inhibitory activity of volatile compounds that were contained in two submerged macrophytes, Ceratophyllum demersum and Vallisneria spiralis, on Microcystin aeruginosa. When the concentration of essential oils was 100 mg/L, the antialgal activities for fresh macrophytes were similar between C. demersum and V. spiralis but stronger than those for dry macrophytes. Essential oils from C. demersum in dry macrophytes showed stronger antialgal activity than those from V. spiralis. There exists a positive correlation between the concentration of the essential oils and the inhibitory activity. The essential oils were composed of fatty compounds, terpenoids, phenolic compounds, phthalates, and some unknown compounds. More than 40% of the essential oils from fresh macrophytes were composed of phthalates, whereas approximately 70% of those from dry macrophytes were composed of lipid compounds and terpenoids. However, approximately 20% of the essential oils from fresh macrophytes were composed of unknown compounds, which were unstable and undetectable in dry macrophytes. Therefore, their chemical structures and bioactivities need further study.     

东太湖水生植物群落结构的演变及其沼泽化

2002年东太湖水生植被调查结果表明,沉水植被和浮叶植被是该湖水生植被的主要生态类型,分布面积分别占全湖总面积73.6%和18.3%。东太湖水生植被主要有9个群丛,其中沉水植被主要的5个群丛是伊乐藻(外来种)群丛、金鱼藻群丛、伊乐藻 微齿眼子菜群丛、菜-伊乐藻 微齿眼子菜群丛、苦草 竹叶眼子菜 黑藻群丛,其分布面积分别占东太湖植被总面积的30.7%、17.2%、16.7%、15.8%、9.3%。随着对东太湖的不断改造和资源的不断利用,20世纪60年代东太湖人工种植沼泽植被菰群丛,20世纪80年代初环湖水陆交错带被围垦而芦苇群丛消失,微齿眼子菜替代竹叶眼子菜而占据东太湖40%的水面。近10a来,东太湖网围养蟹迅速发展,占全湖总植被面积25.6%的沼泽植物——菰群丛及其占40%的微齿眼子菜群丛被清除,外来种伊乐藻和无根植物金鱼藻分布面积达90%的湖区。东太湖水生植被由20世纪50年代的原生演替到现在的次生演替,群落演变激烈,同时东太湖沼泽化进程加剧。     

水体无机碳条件对常见沉水植物生长和生理的影响

为了解水华引起的水体无机碳变化对沉水植物生长的影响,对8种沉水植物:金鱼藻、穗花狐尾藻、篦齿眼子菜、光叶眼子菜、微齿眼子菜、伊乐藻、菹草和黑藻在不同无机碳浓度下的生物量、株高、叶绿素以及光合和呼吸速率进行了比较研究.结果表明8种沉水植物均能利用HCO3-作为光合无机碳源,在1.5 mmoL/L外源HCO3-浓度下能促进金鱼藻、菹草和伊乐藻的生长,提高其光合速率;在2.5 mmol/L外源HCO3-浓度下能促进狐尾藻、光叶眼子菜、黑藻、微齿眼子菜和蓖齿眼子菜的生长,提高其光合速率.在CO32-为优势碳源时,8种沉水植物表现出不同的适应性,发现微齿眼子菜、篦齿眼子菜和黑藻在整个实验范围内生长未受抑制,且在不同浓度下表现生长和光合速率的促进,说明这三种沉水植物对[HCO3-]/[CO32-]比值和pH具有较广适应范围.而当CO32-成为优势碳源时,金鱼藻和伊乐藻的生长受到抑制,狐尾藻、菹草和光叶眼子菜均死亡,表明[HCO3-]/[CO32-]比值和pH是这5种沉水植物生长的重要限制因子.     

不同基质对四种沉水植物生长的影响

通过模拟试验,研究了太湖五里湖主要3种基质类型(沙石、生土、湖泥)对4种沉水植物(苦草、马来眼子菜、金鱼藻、轮叶黑藻)生长的影响. 结果表明,生长于沙石、生土、湖泥上的苦草和马来眼子菜平均生物量分别为72.37、126.25、134.10 g和40.0、72.10、90.70 g,而金鱼藻和轮叶黑藻平均生物量分别为0.27、6.58、73.64 g和0.17、3.26、84.42 g,说明湖泥较适合这四种沉水植物生长. 苦草和马来眼子菜对相对贫瘠的生土有较强的适应性,而金鱼藻和轮叶黑藻不适宜在生土中生长. 生长在沙石上的4种沉水植物的生物量和株高最低,其中金鱼藻和轮叶黑藻于试验期间死亡.苦草的根系活力(TTC)低于马来眼子菜,生长在沙石、生土、湖泥中苦草的根系活力分别为0、(0.16±0.05) mg·g^-1·h^-1和(0.36±0.33) mg·g^-1·h^-1,而马来眼子菜则分别为(2.68±0.34) mg·g^-1·h^-1、(2.30±0.77) mg·g^-1·h^-1、(5.24±0.67) mg·g^-1·h^-1. 叶绿素、质膜透性和丙二醛(MDA)的测定结果进一步证明了以上结论.此外,苦草、马来眼子菜和轮叶黑藻对基质有较强的沁氧能力,其大小顺序为苦草＞马来眼子菜＞轮叶黑藻.     

梁子湖六种沉水植物种群数量和生物量周年动态

研究了梁子湖子湖之一满江湖的六种沉水植物种群数量和生物量在1997.3-1998.3的月动态。结果表明:满江湖沉水植物群落中,优势种为黄丝草、金鱼藻和穗状狐尾藻;六种沉水植物种群最大密度、最大单位面积生物量出现的月份各不相同,但两者变化的趋势一致。黄丝草、穗状狐尾藻种群为增长型种群,金鱼藻、苦草、黑藻种群稳定发展,菹草种群有衰退的趋势。沉水植物群落的最大生物量达到4676g/m2(鲜重,10月),总水草的最大密度为1865枝/m2(11月).根据1997年3-12月植物生长期内的数据,拟合出了六种沉水植物和总水草的生长模型方程。       

Allelopathic activity of Ceratophyllum demersum L. and Najas marina ssp. intermedia (Wolfgang) Casper

Hydrobiologia - We investigated the allelopathic activity of two submersed macrophytes with different growth forms and nutrient uptake modes, Ceratophyllum demersum and Najas marina ssp....     

Invertebrate grazing during the regenerative phase affects the ultimate structure of macrophyte communities

1. Although the biomass of freshwater macrophytes consumed by invertebrate herbivores (excluding crayfish) is usually low, there is growing evidence that invertebrates do exert a structuring effect on macrophyte communities. To explain this, we postulated that the effect of invertebrates may be concentrated on macrophytes during their regenerative phase.
2. We tested this hypothesis by means of a mesocosm-based experiment, in which we investigated the effects of different densities of pond snails [ Lymnaea stagnalis (L.)] on macrophytes regenerating from the natural sediment propagule bank.
3. After 2 months, a diverse macrophyte community had established in the absence of snails, mainly from sexual propagules. Under moderate snail grazing (4 individuals m⁻²), the ultimate biomass of macrophytes was similar, but its species composition differed dramatically. Only a few unpalatable taxa, such as Ceratophyllum demersum and Nymphaeaceae, persisted. Moreover, the relative success of macrophytes regenerating from vegetative rather than sexual propagules improved. Under higher snail grazing (20 m⁻²), all macrophytes disappeared before the end of the experiment.
4. These results confirm that snails at natural densities can have a strong effect on the ultimate structure of macrophyte communities by selectively consuming some species at a juvenile stage. Therefore, the regenerative phase can be seen as a window of opportunity for invertebrate grazers, which can have a qualitative effect on communities that is disproportionate to the biomass consumed.     

Inhibition of photosystem II (PSII) electron transport as a convenient endpoint to assess stress of the herbicide linuron on freshwater plants

Effects of the herbicide linuron on photosynthesis of the freshwater macrophytes Elodea nuttallii (Planchon) St. John, Myriophyllum spicatum L., Potamogeton crispus L., Ranunculus circinatus Sibth., Ceratophyllum demersum L. and Chara globularis (Thuill.), and of the alga Scenedesmus acutus Meyen, were assessed by measuring the efficiency of photosystem II electron flow using chlorophyll fluorescence. In a series of single-species laboratory tests several plant species were exposed to linuron at concentrations ranging from 0 to 1000 μg l−1. It was found that the primary effect of linuron, inhibition of photosystem II electron flow, occurred with a half-lifetime of about 0.1 to 1.9 h after addition of linuron to the growth medium. The direct effect of the herbicide on photosynthesis appeared to be reversible. Complete recovery from the inhibition occurred with a half-lifetime of 0.5 to 1.8 h after transfer of linuron treated plants to linuron free medium. The EC50,24h of the inhibition of photosystem II electron transport by linuron was about 9–13 μg l−1 for most of the macrophytes tested. For S. acutus the EC50,72h for inhibition of photosystem II electron flow was about 17 μg l−1 for the free suspension, and 22 μg l−1 for cells encapsulated in alginate beads. In a long-term indoor microcosm experiment, the photosystem II electron flow of the macrophytes E. nuttallii, C. demersum and the alga Spirogyra sp. was determined during 4 weeks of chronic exposure to linuron. The EC50,4weeks for the long-term exposure was 8.3, 8.7 and 25.1 μg l−1 for E. nuttallii, C. demersum and Spirogyra, respectively. These results are very similar to those calculated for the acute effects. The relative biomass increase of E. nuttallii in the microcosms was determined during 3 weeks of chronic exposure and was related to the efficiency of photosystem II electron transport as assessed in the different treatments. It is concluded that effects of the photosynthesis inhibiting herbicide on aquatic macrophytes, algae and algae encapsulated in alginate beads can be conveniently evaluated by measuring photosystem II electron transport by means of chlorophyll fluorescence. This method can be used as a rapid and non-destructive technique in aquatic ecological research. This revised version was published online in August 2006 with corrections to the Cover Date.     

蜡质标本制作与保存对沉水植物稳定同位素的影响

实验通过模拟传统方法制作和保存蜡质标本, 旨在探究制作和保存的不同阶段对3种沉水植物碳、氮稳定同位素值的影响。结果表明, 制作和保存标本的过程均会对沉水植物的碳、氮稳定同位素值产生影响。植物标本压制的过程显著降低了沉水植物平均碳稳定同位素值, 其中马来眼子菜下降了1.78‰, 穗花狐尾藻下降了0.98‰, 金鱼藻下降了0.72‰。在压制过程中氮稳定同位素值只有金鱼藻显著下降了1.1‰。沉水植物标本制作的浸泡过程使穗花狐尾藻和马来眼子菜的碳稳定同位素值分别出现了1.00‰和0.52‰的上升, 金鱼藻的碳稳定同位素值增长小于0.08‰, 氮稳定同位素值没有显著变化。沉水植物对标本制作和保存的过程响应存在种间差异。在制作和保存过程中对植物碳稳定同位素产生的影响大于氮稳定同位素值。因此建议, 如果所研究对象的稳定同位素生态学差异小于3‰, 蜡质标本的样品需要进行实验校准, 不然会对结果产生影响。     

盐碱池塘水生大型植物的研究

于1998 年4 月至1998 年9 月对高青盐碱池塘的水生大型植物种类组成、生产力及其影响因子进行了野外调查和试验研究。结果表明高青盐碱池塘共有水生植物12 种。常见的优势种有沉水植物:菹草、角果藻、金鱼藻;挺水植物:芦苇、荆三棱、莲和香蒲;漂浮植物:浮萍, 以及大型藻类布氏轮藻。种类少而优势种突出是盐碱池塘大型植物的显著特点。有水草池塘与无或少水草池塘相比, 透明度大、pH 值高、浮游植物生物量和叶绿素a 含量低、营养盐含量也低。在表层光照度7200lx、水温28~30℃的条件下, 菹草、角果藻和轮藻的毛产量分别为1.70、1.56 和1.50mgO₂·L^-1·h^-1·g^-1。除光照、水温、pH 等因素外, 含盐量和碱度对大型植物的初级生产力具有重要影响, 菹草和角果藻的生产力最高时的含盐量均为3g·L^-1, 前者适宜的碱度为6.69 mmol·L^-1, 而后者则为3.82 mmol·L^-1。菹草、角果藻、金鱼藻和浮萍对NH₄-N 的吸收速率相近, 而对PO₄-P 的吸收速率则角果藻 > 菹草 > 浮萍 > 金鱼藻。文后对盐水水体大型植物特点、菹草生产力及其影响因素、如何防止养鱼池大型植物危害及大型植物与浮游植物的关系进行了讨论。     

梁子湖优势沉水植物冬季种子库的初步研究

初步研究了梁子湖6种优势沉水植物如黄丝草、金鱼藻、菹草、黑藻、苦草和穗状狐尾藻等在冬季的广义种子库（种子、芽苞、断枝等）,包括它们的繁殖特性、种子在小、结构及萌发时的衰减曲线等问题,主要结果为：（1）在梁子湖不同区域内,种子库大小不相同,满江湖、前江大湖、中湖和管理局网围内种子库分别为714.4粒／m^2、107.5粒／m^2、331.9粒／m^2和159.3粒／m^2。种子库的大小受到现实的种群数量、投鱼强度、人类干扰等因素的影响。（2）黄丝草、金鱼藻、菹草种九的种子库占有明显优势,全湖平均分别为198.8粒／m^2、91.7粒／m^2和21.4粒／m^2。（3）每一种植物种群广义种子库的构成和比例具有差异,金鱼藻、菹草、苦草、黑藻四种植物种子库中,无性繁殖体占有主要的地位;黄丝草、穗状狐尾藻两种植物种子库中,种子占有很大的比例,上述六种植物均可用种子和无性繁殖体来产生幼苗,补充到肿群中去。（4）种子库一般存在冬季休眠（菹草为夏眠）,春季种子库萌发,尤其在3月和4月是种子库萌发的高峰期。     

Leishmania aethiopica: strain identification and characterization of superoxide dismutase-B genes

This study was performed to characterize the genes that code for superoxide dismutase (SOD) in Leishmania aethiopica. It involved three main steps: specimen collection and parasite isolation, species identification, and molecular characterization of the SOD genes. Out of 20 skin slit specimens cultured and processed from suspected cutaneous leishmaniasis patients enrolled in the study, five (25%) were found to be positive for motile promastigotes. Isoenzyme electrophoresis and PCR-RFLP results confirmed that the isolates were L. aethiopica. Superoxide dismutase-B (SODB) genes were identified from L. aethiopica for the first time. Iron superoxide dismutase-B genes amplified from promastigotes of L. aethiopica (LaeFeSODB) were similar in size to the SODB genes of other Leishmania species. Nucleotide sequences of LaeFeSODB1 showed 95.4, 93.5, and 97.3% identity with L. donovani SODB1 (LdFeSODB1) L. major SODB1 (LmFeSODB1) and L. tropica SODB1 (LtrFeSODB1), respectively. Similarly, LaeFeSODB2 showed 95.9 and 94.1 and 97.6% identity with LdFeSODB2 and LmFeSODB2 and LtrFeSODB2, respectively. On the other hand, predicted amino acid sequence comparison indicated that LaeFeSODB1 had 91.3, 89.8, and 93.9% identity with LdFeSODB1, LmFeSODB1, and LtrFeSODB1, respectively. The difference in nucleic acid sequence of LaeFeSODB from that of LmFeSODB and LtrFeSODB can be utilized to develop specific molecular methods that help differentiate these species in places where there is an overlap in the distribution of these species. In addition, the data provide information about the situation of L. aethiopica with respect to SODB genes.     

Patterns of microbial food webs in Mediterranean shallow lakes with contrasting nutrient levels and predation pressures

Hygraula nitens is a New Zealand native moth with aquatic larvae that feed on submerged aquatic plants. The larvae have been mainly observed using native Potamogeton and Myriophyllum species as a food source, although some studies reported larvae feeding on the alien macrophytes Hydrilla verticillata, Lagarosiphon major and Ceratophyllum demersum. Experimental mesocosm studies showed larvae had a major effect on H. verticillata, C. demersum, L. major, Elodea canadensis and Egeria densa. In both no choice and choice experiments H. nitens larvae showed a clear preference for and the highest consumption of C. demersum, while the native macrophyte Myriophyllum triphyllum ranked fourth out of five alien and two native plant species, indicating a preference of the larvae for alien macrophytes. Additional choice experiments using C. demersum, sampled from different waters in NZ, illustrated that there was a clear difference in H. nitens preference for plants based on their source. However although C. demersum had the lowest leaf dry matter content (LDMC) compared with the other macrophytes, neither the LDMC nor leaf carbon, nitrogen, phosphorus or total phenolic contents alone could explain the preferences of H. nitens, and we conclude that food choice is based on a combination of these and/or additional factors.     

Wetland Restoration and Invasive Species: Apple snail (Pomacea insularum) Feeding on Native and Invasive Aquatic Plants

The apple snail Pomacea insularum is an aquatic invasive gastropod native to South America that has the potential to cause harm to aquatic ecosystems, wetland restoration, and agriculture. To predict the potential impact of this snail on aquatic ecosystems, we tested the feeding rate of P. insularum , under laboratory nonchoice experiments, for 3 species of invasive macrophytes and 13 species of native aquatic plants that are important for wetland restoration and health. High levels of consumption were recorded for four native species ( Ceratophyllum demersum , Hymenocallis liriosme , Ruppia maritima , and Sagittaria lancifolia ) and three invasive species ( Colocasia esculenta , Alternanthera philoxeroides , and Eichhornia crassipes ). In contrast, less than 10% of the biomass of Spartina alterniflora , Scirpus californicus , Thalia dealbata , and Typha latifolia was consumed by P. insularum over the test period. The palatability of macrophytes was negatively correlated with dry matter content, making our results generalizable to all regions where this invader may be present. Based on our results, wetland restoration in areas invaded by P. insularum should focus on emergent structural species with low palatability. Apple snails should not be considered as agents of biocontrol for invasive plants; although apple snails fed on invasive plants at a high rate, their consumption of many native species was even greater.     

不同营养状态下金鱼藻的生理响应

通过静态模拟实验,比较研究了不同营养水平(中营养、富营养、重富营养和Hoagland植物培养液)下培养的金鱼藻(Ceratophyllum demersum)的蛋白质、叶绿素含量,过氧化物酶(POD)及超氧化物酶(SOD)活性变化.研究发现,总N、总P的变化会影响金鱼藻的生物合成,当水环境总氮浓度低于1 mg·L^-1,总磷浓度低于0.1 mg·L^-1时,金鱼藻茎叶的叶绿素合成较低,其茎蛋白含量迅速下降.金鱼藻在富营养水平(1 mg TN·L^-1,0.1 mg TP·L^-1)下抗氧化防御酶活跃,POD、SOD活性增高.研究表明,金鱼藻较适应于富营养水环境,水体营养盐继续增加对金鱼藻有胁迫作用,过高营养盐浓度(重富营养和Hoagland 培养液)影响金鱼藻的抗逆能力.     

Heavy metal adsorption properties of a submerged aquatic plant (Ceratophyllum demersum)

Heavy metals can be adsorbed by living or non-living biomass. Submerged aquatic plants can be used for the removal of heavy metals. In this paper, lead, zinc, and copper adsorption properties of Ceratophyllum demersum (Coontail or hornwort) were investigated and results were compared with other aquatic submerged plants. Data obtained from the initial adsorption studies indicated that C. demersum was capable of removing lead, zinc, and copper from solution. The metal biosorption was fast and equilibrium was attained within 20 min. Data obtained from further batch studies conformed well to the Langmuir Model. Maximum adsorption capacities (q(max)) onto C. demersum were 6.17 mg/g for Cu(II), 13.98 mg/g for Zn(II) and 44.8 mg/g for Pb(II). Kinetics of adsorption of zinc, lead and copper were analysed and rate constants were derived for each metal. It was found that the overall adsorption process was best described by pseudo second-order kinetics. The results showed that this submerged aquatic plant C. demersum can be successfully used for heavy metal removal under dilute metal concentration.     

Feeding behaviour of yearling and older hybrid grass carp

Hybrid grass carp resulting from the cross of a female grass carp, Ctenopharyngodon idella (Val.), and a male bighead carp, Hypophthalmichthys ( Aristichthys ) nobilis Rich., 12–18 months old ( c . 300 mm T.L.) were studied in a two-part experiment to determine feeding preference and total daily consumption fish^-1 on selected species of aquatic plants. Fish were maintained in circular pools with 6840·8 1 of water inside a temperature-controlled greenhouse. Preference tests were conducted at three temperature ranges; 25–28° C, 17–20° C and 12–15° C. Based on the time to complete consumption or the relative quantity consumed, the most preferred plant was Lemna gibba when in combination with six other species. Chara sp., Najas guadalupensis and Potamogeton peciinatus were readily consumed and considered to be of about equal preference. Ceratophyllum demersum and Myriophyllum brasiliense were least preferred. Hybrid grass carp generally consumed as much plant material species^-1 and in the same order of preference at the 12–15°C range as they did at 25–28° C. In the second part, mean daily consumption (g) fish^-1 at 25·7–31·0° C for five plant species tested separately was as follows: Chara sp. 369·8; Lemna gibba 178·2; Najas guadalupensis 172·6; Hydrilla verticillata 106·4 and Ceratophyllum demersum 8·8.     

除草剂对水生植物的生理生态效应

首先研究了常用除草剂对水生植物的生理生态效应。结果表明在 12种除草剂中 ,乙草胺、丁草胺、艾割对紫萍 (Spirodelapolyrhiza (L .) Schleid)、金鱼藻 (Ceratophyllum demersum )生长影响显著。其后进行的丁草胺对金鱼藻生物量及生理生化影响研究表明 :金鱼藻生物量 (干重 )随丁草胺浓度的升高显著下降 ,处理后 16 d,两者呈显著的负相关。丁草胺处理后金鱼藻光合放氧速率明显下降 ,至 16 d,2、4、6、8m g/L处理分别比对照减少 36 .0 2 %、4 1.6 4 %、4 2 .74 %和 4 8.4 3% ;呼吸耗氧速率亦显著下降 ,4、6、8m g/L处理分别比对照下降 2 5 .87%、6 6 .6 4 %、6 7.94 %。呼吸耗氧速率的改变与丁草胺浓度呈极显著的负相关 ;丁草胺处理后金鱼藻叶绿素含量显著下降。谷胱甘肽 - S-转移酶 (GSTs)的变化也与丁草胺处理浓度有关 ,低浓度 (1m g/L )呈现先高后低 ,至 16 d显著低于对照 ,高浓度 (8mg/L )为先低后逐渐恢复。除草剂对水生植物的影响有可能影响整个水生生态系的功能。     

武汉东湖周丛原生动物生态

作者于1963年12月—1964年12月对东湖Ⅳ、Ⅴ两个采样站的聚草、金鱼藻、黄丝草上周丛原生动物进行了周年的定性和定量的观察。共观察到175种周丛原生动物,其中真周丛原生动物占62.9%,伪周丛原生动物占37.1%。两个采样站、三种水草上原生动物数量周年变动均有共同的趋势,即在低温的冬季出现数量高峰,左右数量变动的优势种类是钟形钟虫,占周丛原生动物总数的80—90%。在Ⅴ站同期进行人工基质上周丛原生动物生态比较,表明其优势种类与水草上相同,但群集速度却以水温高的8—9月份为最快。通过金鱼藻生物量、金鱼藻上和人工基质上原生动物数量三者关系的分析,认为影响周丛原生动物数量变动的重要因子是水草本身的生长情况。文中分析了周丛原生动物与水体污染程度的关系,指出着生原生动物是迅速监测水体污染程度的优良指示生物。