β-六六六对多刺裸腹溞生命表统计学参数的影响

应用生命表统计学方法研究了不同浓度(0.001、0.01、0.1、1、10、100和1000μg/L)的β-六六六对多刺裸腹溞(Moina macrocopa)种群统计学参数的影响。结果表明,与对照组相比,浓度为1000μg/L的β-六六六显著降低了多刺裸腹溞出生时的生命期望和净生殖率,100和1000μg/L的β-六六六显著降低了多刺裸腹溞的世代时间,0.1和1μg/L的β-六六六显著提高了多刺裸腹溞的种群内禀增长率。     

3种微生态制剂对大型溞存活、生殖和种群增长的影响

研究了3种微生态制剂(复合微生态制剂Ⅰ、复合微生态制剂Ⅱ和芽孢杆菌)对大型溞的急、慢性毒性影响,分析比较了3种微生态制剂的安全使用剂量以及对大型溞生殖和种群增长的影响.试验结果表明,3种微生态制剂对大型溞死亡率影响均显著(P < 0.05),从安全浓度来看,对大型溞的毒性作用依次为:复合微生态制剂Ⅱ>复合微生态制剂Ⅰ>芽孢杆菌;在安全浓度范围内,3种微生态制剂对大型溞亲代(P)的生殖和种群增长均有明显的促进作用,表现在随微生态制剂浓度的升高,P代的净生殖率(R0)和内禀增长率(rm)均显著增加(P < 0.05),其中以复合微生态制剂Ⅰ的效果最好,R0最高值为对照组的7倍,rm最高值为对照组的1.7倍;3种微生态制剂对大型溞子一代(F1)和子二代(F2)的生殖和种群增长均没有促进作用.     

铜绿微囊藻对萼花臂尾轮虫与大型溞竞争关系的影响

为探究铜绿微囊藻(Microcystis aeruginosa)浓度变化对浮游动物竞争关系的影响,通过控制实验法,评估了在3个铜绿微囊藻浓度梯度下,萼花臂尾轮虫(Brachionus calyciflorus)和大型溞(Daphnia magna)之间的种间竞争关系。结果表明不同浓度铜绿微囊藻对萼花臂尾轮虫、大型溞的增长及二者种间竞争影响具有差异,并且在3种铜绿微囊藻浓度下均以大型溞为主要优势类群。低浓度(5×10⁴ cells/m L)铜绿微囊藻仅促进大型溞种群增长(P<0.01),大型溞占据主要优势地位;中浓度(1×10⁵ cells/m L)铜绿微囊藻对萼花臂尾轮虫和大型溞增长均有显著影响(P<0.01),在此浓度下大型溞在种群竞争中依旧占优势地位,使得萼花臂尾轮虫种群衰亡;在高浓度铜绿微囊藻(5×10⁵ cells/m L)环境中种群生长均受到抑制(P<0.01),在共培养体系中仅大型溞种群存活。在无其他外在影响因素存在时,实验结果显示在不同浓度的铜绿微囊藻下,大型溞均占优势,说明铜绿微囊藻的浓...     

氮磷浓度对藻-溞-草间相互作用的影响

为了解氮磷浓度对生物操纵效果的影响, 以小球藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和大型沉水植物的代表, 建立了它们之间相互作用的水生微宇宙模型。研究了在25℃、2000—3000 lx 的温度和光照下, 不同氮磷浓度对三者生长的影响。结果表明: 两者共培养时, 在高氮(10.5 mg/L)条件下, 磷浓度小于0.1 mg/L 对大型溞繁殖和金鱼藻的生长有利; 磷浓度介于0.1—2 mg/L 时小球藻呈大暴发趋势, 而金鱼藻的生长则明显受抑制。在低氮(0.5 mg/L)条件下, 磷浓度不大于0.5 mg/L, 大型溞对小球藻有较好的抑制作用, 金鱼藻与小球藻无显著互抑现象; 磷浓度增大为2 mg/L 时, 小球藻对金鱼藻生长产生明显抑制。在0.05—2 mg/L 的磷浓度范围及高氮和低氮条件下三者共培养时, 大型溞数量及金鱼藻生物量均不同程度的升高,且小球藻数量得到了有效抑制, 以磷浓度为0.1—0.5 mg/L 时效果最佳; N/P 比值对藻、溞、草间的相互作用有重要影响, 在藻-溞系统中, 大型沉水植物的加入可以大大提高控藻效果, 减小N/P 比值波动带来的不利影响。与低氮情况相比, 高氮条件对金鱼藻、大型溞及小球藻的增长均存在一定抑制作用。磷浓度为0.5 mg/L时的水体氮磷去除效果好于其他磷浓度梯度。       

氯化高汞对大型溞的慢性毒性

在换水静置条件下(25℃),氯化高汞(以Hg++计)对大型溞的48小时LC50值及其可信限为13.5(±2.1)微克/升。试验个体饲以斜生栅藻单个培养,在汞含量为1—21微克/升浓度下,产仔总数经方差分析表明组间差异显著(FF0.05)。各浓度组(X)与产仔总数(Y)的关系为:Y=-51.823X+4320.960(r=-0.904,p0.01)。净增殖率(R0)随浓度升高而逐渐下降。存活和生长用方差分析及D值检验表明对照组与各浓度组之间(差异数分别小于各自的D值20.89和0.1749),没有显著差异。各浓度组对内禀增长能力(rm)和世代平均周期(T)影响不大。根据大型溞的生物学基本参数,其体长的生长模型为: lt=4.57-3.5177e-0.00838t.       

磷浓度对小环藻、大型溞和金鱼藻三者相互作用的影响

为了解磷浓度对水生植被恢复和生物操纵效果的影响, 分别用小环藻(Cyclotella sp.)、大型溞(Daphnia magna)和金鱼藻(Ceratophyllum demersum)代表浮游植物、浮游动物和大型沉水植物建立水生微宇宙模型, 在25℃、2600 lx光强和11 mg/L氮浓度条件下, 分别研究小环藻与大型溞、小环藻与金鱼藻、小环藻-大型溞-金鱼藻共培养时4种磷浓度(0.05、0.1、0.5和2 mg/L)下小环藻、大型溞、金鱼藻的增长率以及培养液中氮磷去除率的变化。结果表明: 小环藻与大型溞、小环藻与金鱼藻两两共培养时, 磷浓度为0.05-2 mg/L时, 金鱼藻和大型溞均生长良好, 小环藻受到明显抑制, 其密度保持较小幅度的正增长。在小环藻-大型溞-金鱼藻三者共培养时, 在0.05-2 mg/L的磷浓度范围内大型溞和金鱼藻生长良好, 与两两共培养相比, 小环藻则受到了更大程度的抑制, 在磷浓度为0.05-0.1 mg/L时藻密度呈现负增长. 这说明在水生态系统中, 大型浮游动物和沉水植物对浮游藻类的联合控制效果远好于各自单独的控制效果, 该控制效果随磷浓度的提高而减弱, 以0.1 mg/L的磷浓度为最佳。在实验结束后测定氮磷去除率发现, 在最低磷浓度(0.05 mg/L),即磷限制时, 水中磷去除率最高, 在最高磷浓度(2 mg/L), 即氮限制时, 水中氮去除率最高。     

磷浓度对铜绿微囊藻、大型溞和金鱼藻三者相互作用的影响

为了解磷浓度对生物操纵和水生植被恢复效果的影响,以铜绿微囊藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和大型沉水植物的代表,在25℃、2000—3000lx光强和11mg/L氮浓度条件下,研究两者和三者共培养时4种磷浓度(0.2、0.5、1.0、1.5 mg/L)下各自的增长率和培养液中氮磷去除率的变化。结果表明:两者共培养时,磷浓度不大于0.2mg/L时,有利于大型溞的繁殖和金鱼藻的生长;磷浓度介于0.5—1.5mg/L时,铜绿微囊藻呈正增长趋势,而金鱼藻的生长则明显受抑制。三者共培养时,所有磷浓度下的大型溞数量及金鱼藻生物量均不同程度的升高,且铜绿微囊藻的生长得到了有效抑制,以磷浓度为0.2—0.5mg/L时效果最佳;N/P比值对藻、溞、草间的相互作用有重要影响,在藻-溞系统中,大型沉水植物的加入可以大大提高抑藻效果,减小N/P比值波动带来的不利影响。磷浓度为0.5mg/L时的水体氮磷去除效果好于其他磷浓度梯度。     

不同浓度纳米二氧化钛对大型溞的繁殖及富集和自净能力的影响

为了弄清不同浓度条件下nTiO₂对大型溞(Daphnia magna)生长繁殖的影响,以6个浓度nTiO₂溶液进行大型溞21 d连续培养试验,结果表明:nTiO₂浓度<1 mg·L^-1时,其对大型溞的生长繁殖的不利影响不显著;nTiO₂浓度>1 mg·L^-1时,不利影响差异显著,且表现出随着浓度增加,存活率和繁殖受到明显抑制。第一次怀孕、产仔天数、产仔次数、一次产仔以及产仔总数都明显减小(p<0.05)。当nTiO₂浓度为5 mg·L^-1时,繁殖基本上停止,内禀增长率r_m由0.347(对照)降到0.106。nTiO₂对大型溞的21 d LC₅₀为4.16 mg·L^-1。24h富集试验结果表明:大型溞在24 h内对nTiO₂的蓄积负荷量呈现随浓度和时间的增加而增强的趋势,在低浓度(2 mg·L^-1)和高浓度(10 mg·L^-1)条件下,大型溞均在24 h时达到最大负荷量。72 h净化试验结果是:大型溞对nTiO₂的净化能力与其富集时的浓度条件有关,富集浓度低(2 mg·L^-1)的,其自身的净化能力强;富集浓度高(10 mg·L^-1)的,其自身的净化能力弱;前者的生物半减期T_1/2为63.3 h,后者的生物半减期T_1/2为181.9 h。     

不同藻类对大型溞存活和生殖的影响

通过生命表技术观察了大型溞（Daphnia magna）在实验室恒定温度（25 ℃）下分别以梅尼小环藻、铜绿微囊藻905、铜绿微囊藻469和斜生栅藻为饵料时的存活率和生殖量变化,并据此探讨了不同藻类对大型溞生活史特征的影响。结果表明：大型溞食用梅尼小环藻和铜绿微囊藻469后生长良好,大型溞在斜生栅藻中也能较好生长,而铜绿微囊藻905对大型溞的生长和繁殖均有不良影响;大型溞对不同藻类的净生殖率(R₀)、世代历期(T)和内禀增长率(r_m)及存活率有不同的影响,梅尼小环藻分别为44.35、11.86、0.32、5%;铜绿微囊藻469分别为48.20、14.25、0.27、30%;斜生栅藻分别为8.10、12.47、0.17、15%;铜绿微囊藻905分别为0、0、0、0。     

吡咯喹啉醌对大型溞繁殖、发育、存活和抗饥饿能力的影响

研究了吡咯喹啉醌（PQQ）对大型溞繁殖、发育、存活时间以及抗饥饿能力的影响。结果表明,5μmol/L的PQQ能够显著促进大型溞的繁殖能力,总产幼量从159.5只增加到207.67只（P〈0.05）。随着浓度增加到15和25μmol/L,其促繁殖效应有所减弱。与对照组相比,PQQ对大型溞发育过程中的龄期数和存活时间（寿命）无显著影响（P〉0.05）。然而,与5μmol/L浓度组相比,15和25μmol/L的PQQ却显著降低了大型溞的龄数和存活时间（P〈0.05）。PQQ能够明显提高大型溞的抗饥饿能力,最长存活时间从对照组的3 d增加到0.5 mmol/L PQQ组的8.33 d（P〈0.05）。     

Effects of cadmium on consumption, assimilation and biochemical parameters of Daphnia magna: possible implications for reproduction

1. The effects of cadmium on consumption, assimilation rates and biochemical parameters of Daphnia magna were determined. 2. The consumption and assimilation rates of 14 days 1.0 ppb Cd treated animals tended to decrease slightly, the decline of these rates at 5.0 ppb Cd (14 days), however, was highly significant (P less than 0.001). 3. The assimilation efficiencies of daphnids exposed to cadmium did not significantly differ from control. 4. No notable changes in the biochemical composition of daphnids could be noticed after 7, 14 and 21 days of cadmium exposure. 5. It seems as if not one metabolic process in particular was depressed due to cadmium, but metabolic activities seemed to be inhibited on the whole. 6. Results are discussed in relation with data of a previous study on the reproduction of D. magna under cadmium stress.     

大型溞生长、生殖和种群增长的研究

年龄6±6小时的纯系大型溞培养在25±1℃静置换水条件下,饲以斜生栅藻,其平均寿命为68.40±9.82天。龄期(x)和年龄(t,天)之间呈曲线迴归关系:t=-2.245+1.510x+0.035x2(r=0.99,p3.86-0.131t)(式中Y为累计生殖量个数,t为天数)。       

Effects of fluoride on growth, reproduction and survival in Daphnia magna

The effects of waterborne fluoride (NaF) on growth, reproduction and survival in Daphnia magna were studied from subnormal to toxic concentrations in hard reconstituted water. The 24- and 48-hr EC50S for immobilization were 205 and 98 mg F (fluoride) 1(-1). Median survival times for fed and unfed Daphnia were reduced at concentrations of F above 8.9 and 10 mg F1(-1), respectively. Growth, determined as body length after 7 and 21 days, was partially inhibited at all concentrations above 3.7 mg F1(-1). Parthenogenetic reproduction was stimulated by all concentrations (dilution factor 0.5) between 0.45 X 10(-3) mg F1(-1) and 3.7 mg F1(-1) and inhibited by all concentrations above 3.7 mg F1(-1), compared to the control with no waterborne fluoride. The highest concentration with a reproduction (number of live progeny/live female) equivalent to the control after 21 days was 4.4 mg F1(-1). However, a progressive decline in reproduction between 14 and 21 days indicates a slight long-term inhibition above 0.58 mg F1(-1). The "safe" concentration equivalent to the geometric mean of NOEC or MATC for D. magna in hard water is 4.4 mg F1(-1), derived as ZEP, the Zero Equivalent Point, for reproduction after 21 days.     

Aliesterase- (Ali-E) activity in Daphnia magna straus as a parameter for exposure to parathion

In vivo exposure of Daphnia magna Straus to parathion in concentrations from 0.05 to 5 µg/l resulted in a concentration-dependent decrease in aliesterase activity of the homogenate of the animals. Decrease in this activity after 48 hours of exposure was maximal for concentrations > 1.5 µg/l and amounted to about 90% of the activity of the blank.     

The heart of Daphnia magna: effects of four cardioactive drugs

We used Daphnia magna bioassays to determine the LC(50) and the effects on the heart of the cardioactive drugs ouabain, verapamil, metaproterenol and metoprolol. Distinctions were made between the pharmacological and toxicological effects of these drugs and the adequacy of physicochemical characteristics of its habitat (reconstituted water). Video microscopy and digital image processing were used to study the pharmacological effects on the heart. D. magna exhibited the expected sensitivity to the reference toxicant sodium dodecyl sulfate with a LC(50) of 15.6+/-4.5 mg/l. All drugs were toxic with 48 h-LC(50) of 2.03 mg/l ouabain, 7.04 mg/l verapamil, 32.45 mg/l metaproterenol and 76.21 mg/l metoprolol. Ouabain was the most toxic and caused a positive concentration-dependent inotropic effect. Verapamil caused positive chronotropic and inotropic effects, while metaproterenol showed positive concentration-dependent chronotropic effects at high concentrations (10(-3) and 10(-4) M). Metoprolol induced a positive chronotropic effect at low concentrations (10(-8), 10(-7), 10(-6) M) and a negative chronotropic effect at high concentration (10(-4) M). Ouabain, metaproterenol and metoprolol in D. magna caused similar effects to those produced in mammals. In contrast, verapamil caused opposite effects. The results suggest the presence of Na(+), K(+)-ATPase receptors to verapamil and of non-specific adrenergic receptors in heart of D. magna.     

Effects of waterborne iron on growth, reproduction, survival and haemoglobin in Daphnia magna

The effects of waterborne iron (FeCl3 X 6H2O) on growth, reproduction, survival and haemoglobin content in Daphnia magna were studied from subnormal to toxic concentrations in hard reconstituted water. Low concentrations of iron stimulated reproduction and haemoglobin synthesis after chronic exposure for 21 days. Maximum reproduction occurred between 0.1 and 1 microgram Fe 1(-1). Juvenile growth was not stimulated by iron but was slightly inhibited between 1 and 8 micrograms Fe 1(-1) and above 128 micrograms Fe 1(-1). A slight inhibition of growth persisted for 21 days. Total haemoglobin content was above the control with no waterborne iron at all but one concentration (512 micrograms Fe 1(-1]. The highest value (3.8 X control value) was found at 2 micrograms Fe 1(-1). The haemoglobin content decreased between 64 and 512 micrograms Fe 1(-1) and increased at higher concentrations. The decrease coincided with an inhibited reproduction. The increase was found in non reproductive survivors. A comparison with a previous study in D. magna suggests that ambient conditions (hardness and pH) and ageing of the water are important for the effects of waterborne iron. At a hardness of 250 mg 1(-1) as CaCO3 and a pH range of 7.0-8.0 the ZEP (Zero Equivalent Point) for reproduction was 158 micrograms Fe 1(-1). Continuous exposure to higher concentrations is expected to lead to extinction of a D. magna population.     

Effects of endosulfan on survival,growth and reproduction of Daphnia magna

1. Acute and chronic toxicity tests with endosulfan were conducted on Daphnia magna. The 24-hr static lc₅₀ was 0.62 mg/l with a coefficient of variation of 14.2%.2. The sublethal effects of 0.12, 0.15, 0.20, 0.25 and 0.31 mg/l endosulfan on the survival, reproduction and growth of D. magna were monitored for 21 days.3. The parameters used to determined the effect of the pesticide on reproduction were: mean total young per female, maximum number of broods, mean brood size, mean number of broods, mean time to first reproduction and intrinsic rate of natural increase (r).4. Growth, as measured by body length, was depressed significantly at all endosulfan concentrations tested. The highest concentrations used (0.20, 0.25 and 0.31 mg/l) caused a decrease in survival and mean total young per female, and an increase in the time to first reproduction. The intrinsic rate of natural increase (r) and the mean number of broods were decreased significantly at all the sublethal concentrations of endosulfan tested.     

1,8-二羟基蒽醌对大型溞的毒性效应

The study on the acute,sublethal and chronic toxicity of 1,8-dihydroxyanthraquinone (1,8-dihAQ) to Daphnia magna showed that the 48 h LC₅₀ was 0.37 mg稬^-1,and the feeding behavior of Daphnia magna was severely affected by the compound.When exposed to 0.2 mg稬^-1 of 1,8-dihAQ for 5 h,the filtration and ingestion rate of Daphnia magna was inhibited by 97%.Chronic toxicity test results indicated that the reproduction ability decreased dramatically after exposing to sublethal concentration of 1,8-dihAQ.It could be inferred that reproduction parameters and intrinsic rate of natural increase were the sensitive parameters in characterizing sublethal toxicity.The NOEC and LOEC values for reproduction parameters were also given.