改性纳米TiO2 对蓝藻的生理生态影响

在自然光照条件和日光灯光照条件下, 用掺1%Ag纳米TiO2 、掺5%Fe2O3纳米TiO2、掺10%ZnO纳米TiO2和纯纳米TiO2对铜绿微囊藻(Synechocystis sp.)PCC6803和集胞藻(Microcystis aeruginosa)进行处理, 并对2种藻样的叶绿素含量、类胡萝卜素含量、体外超氧自由基含量及超氧化物歧化酶(superoxidase dismutase, SOD)活性进行测定。结果表明, 自然光照条件比日光灯光照条件更利于纳米材料光催化反应的进行; 改性后的3种纳米材料对蓝藻的抑制效果要好于纯纳米TiO2,其中效果最好的为掺1%Ag纳米TiO2; 2种藻样在适应由光催化剂引发光催化而产生的自由基胁迫时, 集胞藻的适应能力比铜 绿微囊藻更强。     

纳米TiO2负载贵金属Pd抑制蓝藻的生长

研究了纳米TiO2和负碱Pd纳米TiO2对蓝藻生长抑制的影响。结果表明,在太阳光照射下,载Pd纳米TiO2能够破坏蓝藻藻囊．与纳米TiO2相比,载Pd纳米TiO2能够更有效地使蓝藻内叶绿素含量、光合速率和呼吸速率以及氧化物歧化酶（SOD）活性降低,超氧自由基增多。研究证明,载Pd纳米TiO2的载Pd量选择1％为最佳。     

草甘膦对可食用蓝藻葛仙米生长和生理的影响

葛仙米（N．sphaeroides）的产量和产地面积逐年减少,这可能与当地广泛使用除草剂草甘膦有关。为此,本文测定了不同浓度（0．15、0．30、0．45、0．6mmol／L）的草甘膦处理的葛仙米的颗粒大小、干重、叶绿素荧光、叶绿素浓度。所有测量参数与浓度和时间显著相关：0．15mmol／L处理组的颗粒直径较对照组小15％（2d后）;叶绿素a浓度和最大量子产率（Fv／Fm）在最高浓度组（0．6mmol／L）4d后开始受到影响;第8天,相对生长速率（以干重计算,大于0．15mmol／L）、光合作用活性（大于0．3mm01／L）均受显著抑制,其中0．15mmol／L处理组相对生长下降60％,而更高浓度处理组出现负生长,0．6mm01／L组藻体漂白死亡。结合实验结果,文章讨论了草甘膦的毒性机理及其对葛仙米（N．sphaeroides）的潜在影响。     

UV-C光催化纳米TiO2对蓝藻生长影响的研究

研究了UV-C光催化纳米TiO2对蓝藻生长的影响。从生理上分析了UV-C光催化纳米TiO2具有促进蓝藻中鱼腥藻7120体内活泼态氧化物O2,.OH和H2O2的产生,抑制藻体中过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和超氧歧化酶(SOD)在内的抗氧化酶活性,降低可溶性蛋白(Soluble Pr)、藻蓝蛋白(C-PC)、叶绿素a(C-Chl a)和类胡萝卜素(C-Carotenoids)含量,最终表现为藻细胞生长代谢中光合速率和呼吸速率迅速降低,细胞增殖中遗传物质核酸含量下降,并出现几乎达到100%的细胞致死率;同时,通过显微镜观察发现,受试蓝藻细胞形态结构发生了明显变化。可以看出,UV-C光催化纳米TiO2能够有效抑制蓝藻生长。     

光合抑制剂DCMU对异养生长蓝藻叶绿素合成的作用

与被子植物不同,蓝藻叶绿素的合成存在依赖于光和不依赖于光的两条途径1,故异养生长的蓝藻在黑暗条件下同样合成叶绿素。在不同营养条件下,蓝藻的叶绿素合成也相对稳定,其含量常作为生物量的指标。已知DCMU是一种光合作用抑制剂,阻断光系统向质体醌的电子传递。有报道显示,DCMU可调控蓝藻Calothrix的细胞分化2。但DCMU对于蓝藻叶绿素合成的作用从未见报道。在对表达glk和lac ZYA基因蓝藻的异养生长研究中3,作者发现DCMU显著抑制丝状固氮蓝藻的叶绿素合成,而对单细胞蓝藻没有影响。       

纳米TiO_2对油松种子萌发及幼苗生长生理的影响

以油松为材料,研究了不同浓度(50～2 000 mg/L)的纳米TiO2对油松种子萌发及幼苗生长和生理特征的影响,以探讨纳米材料对林木生长发育的调节作用.结果显示:各浓度纳米TiO2处理对油松种子萌发、幼苗生长及生理功能的改善均有一定程度的促进作用,且促进效应随着处理浓度的增加呈先升后降的趋势;1 000 mg/L纳米TiO2处理对种子发芽率、发芽势、发芽指数、活力指数、苗高、鲜重的提高以及霉变率的抑制作用效果最佳,它们依次分别比对照极显著提高28.00%、18.00%、12.36%、126.95%、19.57%、36.89%和下降15.33%(P<0.01);500 mg/L纳米TiO2能最有效增加油松幼苗根长、根系活力及其叶片蛋白质含量、SOD活性、POD活性,降低其细胞质膜相对透性和丙二醛含量,它们分别比相应对照极显著增加111.91%、53.85%、16.32%、170.93%、141.94%和降低45.18%、51.27%.研究表明,适当浓度的纳米TiO2处理不仅能显著促进油松种子的萌发和幼苗生长,而且能改善幼苗的生理功能,增强其抗逆能力.     

生理高温对佛州侧耳超氧物歧化酶的影响*

佛州侧耳(PleurotusfloridanusSinger)子实体在生理高温(32±l℃)条件下,O2吸收速率和超氧阴离子(O2-)产生的速率增加;脂质过氧化产物丙二醛(MDA)的积累增多.超氧物歧化酶(SOD)活性升高;过氧化氢酶(CAT)和过氧化物酶(POD)的活性相应地发生变化;放线菌素D抑制生理高温下SOD活性的升高;O2-清除剂甘露醇和外源SOD都影响生理高温对SOD的诱导效应;表明该侧耳在生理高温条件下SOD酶活性激应性的升高是O2-参与了SOD基因表达的调控,促进酶蛋白的合成.     

CO2对NaCl胁迫下蓝藻固氮的影响

培养系统中CO2浓度增高时,蓝藻的固氮活性成倍增长,NaCl对固氮的胁迫明显减弱。能量供应受限（添加ATP形成抑制剂或暗处理）、厌氧环境（Ar或N2中）和在分子氧下,CO2的有益作用减弱或消失,反之或改善合成固氨酶蛋白所需物质的供应（CO2和N2以及地和O2的加合）时则有促进。在CO2浓度提高的情况下,外源蔗糖对NaCI胁迫蓝藻固氮无明显的缓解效应。     

氮磷营养盐对四种淡水丝状蓝藻生长的影响

通过设定不同的氮、磷营养盐浓度,在实验室条件下研究了不同浓度的氮和磷对4种淡水丝状蓝藻:皮质颤藻、尖细颤藻、蛇形颤藻和坑形细鞘丝藻生长的影响.结果表明,皮质颤藻和坑形细鞘丝藻对高浓度的氮、磷有着较强的适应能力,在硝态氮浓度0.016mg·mL^-1～2.0mg·mL、磷浓度1.36mg·mL^-1～13.6μg·mL时生长较好.4株藻在只存在氨态氮的情况下生长都受到抑制.     

几种农药对固氮蓝藻生长的影响

在我们进行固氮蓝藻对水稻肥效的田间试验时,就遇到这样的一个问题：施用农药来防治水稻的病虫害对固氮蓝藻的生长繁殖有没有影响?若果施用的农药对固氮蓝藻有毒害作用,那么,要在田间接种繁殖固氮蓝藻作为水稻的氮肥源,便会和防治病虫害发生矛盾,要推广使用固氮蓝藻就会有许多困难了。     

The Influence of Toxic and Filamentous Blue-green Algae on Feeding and Population Growth of the Rotifer Brachionus rubens

The effect of toxic and of filamentous blue-green algae on feeding and population growth of the rotifer Brachionus rubens was investigated in laboratory experiments. A toxic strain of Microcystis aeruginosa was ingested, but rotifers cultured with Microcystis died faster than nonfed controls. The rigid filaments of Cylindrospermopsis raciborskii were not ingested, reduced the ingestion of simultaneously offered algae, and depressed population growth rates. The soft filaments of Anabaena flos-aquae were ingested at a moderate rate, did not reduce ingestion of other algae, and were used as an additional food in population growth experiments.     

Blue-green Dominance in Lakes: The Role and Management Significance of pH and CO2

Field and laboratory experiments show that when nutrients (N and P) are added to a mixed population of algae, blue-greens predominate. However, if CO₂ is added also, or if pH is lowered with HCl, greens predominate. The phenomenon is reproducible, and works with most lakes. Although most successful at pH 5.5, the shift to greens can be made to happen at pH values as high as 8.5. Most blue-greens appear to be susceptible to the shift, and Scenedesmus and Chlorella are the predominant greens resulting. If pH is raised, the shift is reversed. The reason for the shift is not known. It may involve competition by the algae for CO₂, but other evidence suggests that the lowered pH stimulates cyanophage production and lysis of the blue-greens, with release of nutrients which then are used by the greens. Analysis of results of lake circulation data from the literature and from experiments suggests that the algal shifts resulting from circulation may involve the same phenomena. Understanding of these phenomena should lead to predictable use of circulation as a lake-management tool.     

Inhibitory and Toxic Effects of Blue-green Algae on Daphnia

The effects of the planktonic blue-green algae, Aphanizomenon gracile, Synechococcus elongatus, and Microcystis aeruginosa, on survival, growth, and food uptake of Daphnia pulicaria were determined. Synechococcus and Aphanizomenon were unsuitable food when offered alone, but did not affect the daphnids negatively when mixed with Scenedesmus. Microcystis was the only one found to be toxic. In pure suspensions of this blue-green, the daphnids did not survive more than 48 hours; they lived a little longer if Scenedesmus was supplied additionally. Growth was markedly reduced when only 50 μg carbon/l of Microcystis was added to the normal Scenedesmus food. It ceased at a concentration of 250 μg C/l. This can be explained by the reduction of food uptake. Very small quantities of Microcystis (10 μg C/l) present in the normal food caused a significant reduction of the filtering rate. Filtering inhibition was associated with the cells. Filtrate of Microcystis suspensions was not effective. Thus, the daphnids must ingest the blue-green cells in order to become toxified. Dual-labelling experiments showed that Microcystis cells are filtered from the medium by Daphnia with the same efficiency as Scendesmus and are not rejected. Toxicity of Microcystis is considered to be an effective defence mechanism against grazing pressure.     

水葫芦对藻类的克制效应

水葫芦对藻类生长有克制作用。其机制主要是由于水葫芦根系向水体分泌的有机物质能伤害和杀死藻类。用水葫芦种植水培养藻类,使藻类的光合作用速率显著降低,叶绿素a破坏,细胞还原TTC的能力下降。在荧光显微镜下可看到藻细胞从鲜红色变为淡蓝绿色。     

The Effect of pH on Copper Toxicity to Blue-Green Algae

The effect of pH on copper toxicity to two planktonic blue-green algae, Aphanizomenon gracile and Oscillatoria redekei, was investigated. Growth rates of the algae without copper treatment decrease with pH, Aphanizomenon is earlier and more affected than Oscillatoria. On the other hand, pH-lowering leads sooner to a toxicity enhancement in Oscillatoria. In the acid range, toxicity retardation occurs in Aphanizomenon. At pH 5.1, shortening of the interval between copper toxicity and copper stimulus is characteristic for both species.     

三种金属氧化物纳米颗粒的水生态毒性

参考国际经济合作与发展组织(OECD)化学品生态毒性测试标准方法,以绿藻(Scenedesmus oblignus)和大型蚤(Daphnia magna)为受试生物,研究了3种金属氧化物纳米颗粒(纳米氧化锌nZnO、纳米二氧化钛nTiO2、纳米氧化铝nAl2O3)水悬浮液的水生生态毒性.结果发现,不同的纳米颗粒具有不同的毒性:nZnO、nTiO2和nAl2O3对斜生栅藻生长的 96 h半效应浓度(EC50)值分别为1.049、15.262、>1000 mg · L-1,而对大型蚤活动抑制的 48 h EC50 值则分别为0.622、35.306 mg · L-1和114.357 mg · L-1.据此可得到3 种金属氧化物纳米颗粒水悬浮液的毒性大小顺序为:nZnO ＞nTiO2 ＞ nAl2O3.此外,不同的生物对金属氧化物纳米颗粒的敏感性也不同,除nTiO2以外,大型蚤对另外2种纳米颗粒的敏感性强于斜生栅藻.实验结果表明,人工纳米材料的生态毒性和环境效应不容忽视,应重视并深入研究此类纳米材料的毒性作用机制和影响因子,以便能对其进行更好的风险管理.     

藻类中添加剂的应用研究进展

藻类富含多种营养元素和活性物质,具有重要的经济价值和广阔的应用前景。现阶段藻类培养多采用露天跑道池,成本低,但易受环境影响。不适宜的环境条件(温度、酸性、重金属、紫外、盐度和光强胁迫等)会造成藻类生产成本上升、产品产量及品质下降等后果,严重制约藻类养殖业及相关产业的发展。添加剂不仅能有效促进藻类生长,还能缓解环境胁迫对其带来的逆境伤害。将近年来添加剂在藻类生长及抗逆方面的应用进行系统汇总,并对已阐明的几种添加剂的作用机理进行分析整理。添加剂在藻类中的应用研究大多停留在生长及生理指标的测定,如藻细胞密度、光系统活性、渗透调节物质含量、脂质含量、过氧化氢酶和硝酸还原酶活力等,仅有少部分研究是利用分子技术测定防御基因的表达情况,尝试进一步探究藻类抗逆性分子机制。旨在为研究者进一步明确常用添加剂在藻类中的信号传导机制及改善非生物胁迫造成的产品产量及品质的问题提供理论依据,具有重要现实意义。