磷酸盐对盐藻生长与物质积累的调控作用

实验研究了不同浓度的磷酸盐对盐藻细胞生长与物质积累的调控作用。结果表明,培养液中供给磷过多或过少都不利于盐藻细胞的生长与物质积累。以培养基中30mg/L的磷浓度对盐藻细胞生长、蛋白质合成与β-胡萝卜素积累的促进作用最大。培养液中磷浓度提高会使盐藻细胞生长与物质积累受到抑制。在培养液中的磷浓度为0mg/L时,单个盐藻细胞中的蛋白质含量最高。     

几种绿藻对西草净的抗性与活性氧防御物质

４种绿藻对除莠剂西草净（Ｓｉｍｅｔｒｙｎ）的反应有很大差异,小球藻、羊角月芽藻、衣藻和四鞭藻的ＥＣ＿（５０）（影响浓度）值分别为７００、２５、２７和１１μｇ／Ｌ不同浓度西草净都能影响绿藻的光合作用,浓度为２００ｐｐｍ６时,羊角月牙藻和四鞭藻的光合抑制率分别为９５．３％和９４．０％,但对小球藻几乎无影响,当浓度增至２０００ｐｐｍ时,对小球藻的光合抑制率为８７％。小球藻中活性氧防御物（ＳＯＤ、ＡｓＡ－ＰＯＤ、ＧＲ等）的活性均比衣藻、羊角月牙藻等高几倍到几十倍,显示小球藻对西草净的抗性和忍耐性可能与它细胞内所含的活性氧防御物活性有关,它们的高活性使小球藻在西草净污染后,对体内生成的活性氧（Ｏ＿２、Ｈ＿２Ｏ＿２、Ｏ＿２等）伤害有解毒作用。     

斜生栅藻在不同磷条件下氮生态幅的研究

为获得斜生栅藻（Scendesmus obliquus）的氮生态幅,研究根据中华人民共和国地表水环境质量标准磷浓度界定,利用谢尔福德（Shelford）耐受定律进行曲线拟合对斜生栅藻在低磷（0.02 mg/L）、中磷（0.2 mg/L）和高磷（0.4 mg/L）三种不同磷浓度下氮的生态幅进行定量表达,获得三种磷起始条件下斜生栅藻生长的最佳氮浓度、氮适宜生长范围和氮耐受范围。研究表明,在三种磷条件下斜生栅藻生长的最佳氮浓度分别为1.02、8.91和18.05 mg/L,对应的最大比生长速率分别为（0.1420.006）、（0.3140.002）和（0.3460.007） /d,氮适宜生长范围分别为（0.521.52）、（4.4813.34）和（11.7224.38） mg/L,氮耐受限度分别为（0.022.02）、（0.0517.77）和（5.3930.71） mg/L。这表明富营养化水体可能引起斜生栅藻的大量生长、繁殖,也暗示了斜生栅藻能作为高氮水环境的一个良好指示生物。       

鲢鲴混养对水体环境的影响

为评估鱼类混养及其排泄物对水体环境的潜在影响,采用室内受控实验研究了鲢（Hypophthalmichthys molitrix）和黄尾鲴（Xenocypris davidi）混养对水体鱼腥藻和水质的影响。实验设置鲢投放组、鲢鲴组合投放组和空白对照组,实验周期14 d。结果发现,鱼类的放养增加了实验水体的营养负荷,有鱼实验组水体中总氮、总磷、氨氮和高锰酸盐指数均高于对照组,且实验后期鲢组的营养盐浓度均高于鲢鲴组;有鱼实验组水体中叶绿素a浓度和藻密度均降低,且鲢鲴组较鲢组降低更为明显;黄尾鲴的加入可以减少水体中鱼类排泄物的积累,鲢鲴组鱼类生物量较鲢组多,但排泄物重量却低于鲢组;鲢鲴组对鱼腥藻的消化率更高,实验结束时达到79.33%,极显著高于鲢组（P<0.01）。即在鲢控藻的基础上,混养黄尾鲴可以减少鲢摄食鱼腥藻后的排泄物重量,减少因鱼类排泄物造成的二次污染。     

C、N、P对杜氏盐藻突变藻株Zea1生长和积累玉米黄素的影响

通过UV辐照和NTG诱变处理杜氏盐藻野生型藻株得到一株杜氏盐藻高产玉米黄素突变株Zea1,以此突变藻株为实验材料,系统研究了光照强度、盐浓度、碳源、氮源、磷源等对Zea1生长和玉米黄素积累合成的影响。葡萄糖在10mmol/L时既适合Zea1生长,又有利于其玉米黄素的积累。KNO3浓度为1mmol/L时最适合突变株藻细胞生长,而(NH4)2SO4浓度为1mmol/L最有利于藻细胞内玉米黄素的积累。综合来看,1mmol/L(NH4)2SO4为最优氮源。KH2PO4浓度为0.1mmol/L时Zea1藻细胞积累玉米黄素含量最高,同时在此浓度下也最适宜藻细胞的生长。讨论了此结果的机理和意义,为利用杜氏盐藻大规模生产玉米黄素提供了理论依据。     

鱼腥藻1017株的混合营养型生长

鱼腥藻１０１７株混合营养型生长有其特点,外源葡萄糖对生长的刺激不仅在低光强（８００ｌｘ）,而且在高光强（７０００ｌｘ）也表现出来。其混合营养型生长速率在８００－７０００ｌｘ范围内随光照强度的增加而增加,在葡萄糖浓度５－２０ｍｍｏｌ／Ｌ范围内随外源葡萄糖浓度增加而增加。鱼腥藻１０１７株混合营养型生长与光能自养生长相比,生长速率明显提高,对数生长期延长,收获物浓度显著增高,生物量显著提高。     

锌对盐藻生长与物质积累的调控作用

实验研究了不同浓度的锌对盐藻细胞生长与物质积累的调控作用。结果表明,培养液中供给锌过多或过少都不利于盐藻细胞的生长与物质积累。以培养基中6 mg/L的锌浓度对盐藻细胞生长、蛋白质合成与β-胡萝卜素积累的促进作用最大。这一锌浓度可用于盐藻的生产性培养。当培养液中锌浓度较高(8 mg/L)或较低(2 mg/L)时,单个盐藻细胞中的蛋白质与β-胡萝卜素含量较高。但此时,因培养液中细胞密度较低,盐藻细胞积累的物质总量仍然较少。在锌浓度较高或较低的逆境条件下,盐藻可能通过适应性反应形成了逆境蛋白质与胡萝卜素等。     

N、P营养盐对塔玛亚历山大藻（Alexandrium tamarense）生长的影响

模拟自然海水营养盐浓度状况,在N、P浓度分别为10-500μg L-1 N和0.74-74μg L-1 P时,研究N、P双因子限制(N、P浓度同时降低,N:P固定为15:1)及单因子限制(保持N或P为最高浓度,只降低一种营养盐浓度)对有毒赤潮藻塔玛亚历山大藻(Alexandrium tamarense)生长的影响。结果表明,塔玛亚历山大藻细胞能较快进入对数生长期,但N、P双因子限制能明显影响其生长,在N、P浓度分别低于100μg L-1 N和15μg L-1 P时,细胞密度无明显增长;而N或P分别受限时,生长态势明显优于N、P同时受到限制的试验组,而且N、P单因子中度限制对生长影响较小。结果说明塔玛亚历山大藻对单因子营养元素限制较强的适应能力,可使其在常常出现单营养因子限制的自然水体中维持一定生长速率和细胞密度,并有助于滤食该藻的贝类体内麻痹性贝类毒素的积累。     

普通小球藻生长与武汉东湖水体磷形态的相关研究

本文探讨了武汉东湖水体中总溶解磷（TSP）、溶解反应磷（SRP）、总反应磷（TRP）、溶解水解磷（SHP）和颗粒磷（PP）对普通小球藻生长的生物有效利用性。进行了普通小球藻生长量与各磷形态及总磷（TP）被利用浓度的一元相关分析,进一步讨论了这些一元相关方程的不足,并用多元回归分析建立了普通小球藻生长量（N）与所测几种磷形态被利用浓度（CTSP,CSRP,CTRP,CSHP,CPP）的相关模型。这些模型可以用于评价湖泊水体富营养化的程度及预测藻的生长潜力。     

几种外源激素对杉木种子萌发的影响

应用ＧＡ、６－ＢＡ和ＡＢＡ等三种外源激素对杉木种于萌发的影响进行了研究．结果表明,ＧＡ较明显促进杉木种子的萌发,而６－ＢＡ和ＡＢＡ则显著地抑制了杉木种子的萌发．当三种激素共同存在时,它们在杉木种子萌发中的相互作用表现为：ＧＡ起促进作用（最适浓度为５０－１００ｐｐｍ）．ＡＢＡ起抑制作用,６－ＢＡ（浓度不超过５０ｐｐｍ）则有解除ＡＢＡ的抑制作用．     

环境汞污染对藻类的毒性效应及其影响因素

综述了汞污染对藻类的毒性效应及影响因素。水环境中汞主要以元素汞、无机汞和有机汞3种形式存在。藻类吸附汞主要分为胞外的快速吸附和胞内的缓慢富集,在安全浓度内,金属汞对藻生长有一定的促进作用,随着浓度增大,抑制藻生长或致死。汞进入藻体细胞后,藻类为了存活会产生一系列保护机制。藻类对汞的排斥和排出作用可能就是对汞耐性的一种重要机制。藻类也可以通过多种方式减少汞进入藻类细胞,以及通过与其他物质结合汞使其排出胞外。温度、pH、生物学因素等影响重金属对藻类的毒性作用。并就藻类对汞耐性和适应机理、利用藻类修复和监测重金属污染、藻类响应汞胁迫的信号转导途径及其保护机制等未来研究领域进行了展望。     

硝酸盐对球形棕囊藻生长和硝酸还原酶活性的影响

以我国南海海域分离的赤潮原因种——球形棕囊藻(Phaeocystis globosa)为材料, 研究了不同硝酸盐浓度下藻细胞生长及硝酸还原酶活性的变化。当培养基中不含硝酸盐时, 藻细胞内硝酸还原酶的活性保持在非常低的水平, 藻细胞的生长受到限制, 不能形成正常的生长曲线: 当培养基中硝酸盐浓度为3.62 mmol.L-1时, 藻细胞的硝酸还原酶活性和比生长速率达到最大。在含有硝酸盐的培养基中, 接种培养后第9天藻细胞硝酸还原酶活性达到最大值, 并且在4种不同硝酸盐浓度下, 藻细胞硝酸还原酶活性的差异性达到极显著水平(P<0.01)。在接种培养第16天藻细胞密度达到最大值, 并且4种不同硝酸盐浓度培养的藻细胞密度之间的差异性也达到极显著水平(P<0.01)。实验结果表明, 在培养基中添加不同浓度的硝酸盐, 对球形棕囊藻细胞硝酸还原酶的活性和藻细胞的生长有极显著的影响, 含有较高硝酸盐的富营养化海域有利于球形棕囊藻细胞的持续生长。     

Influence of pesticides on the growth of cyanobacteria.

Two unicellular and two filamentous cyanobacteria (blue-green algae) were exposed under conditions optimal for photoautotrophic growth to eleven pesticides. Low concentrations (0.01 to 5 ppm) of diuron, atrazine, and paraquat inhibited growth. With MCPA, MCPP, 2,4-D, milstem and ethrel, marked inhibitory effects were achieved only at concentrations above 100 ppm. Growth was inhibited by glyphosate, DDT, and thiram at intermediate concentrations. In some cases, the effective concentration of the pesticide varied considerably with the organism tested.     

EXOGENOUS STEROIDS AND GROWTH OF NEOSPONGIOCOCCUM SP. (CHLOROPHYTA)1

Of the various types of steroids found in nature, only sterols (steroids whose molecules possess an 8- to 10-carbon atom hydrocarbon side chain at position 17 of the perhydrocyclopentanophenanthrene ring) are known to be common constituents of algae. Little is known of the effects of steroids in the environment upon the growth and survival of algae. This paper investigates the growth of the green alga Neospongiococcum sp. in medium containing steroids. Bile acids are not inhibitory, even at a concentration of 100 ppm. Some sterols inhibit growth when present in the medium at a concentration of 100 ppm, but not at 10 ppm. Testosterone and β-estradiol, which have no carbon atom side chain at ring position 17, inhibit growth at a concentration of only 10 ppm. Steroids whose molecules possess a 2-carbon atom side chain at ring position 17 and a keto group at the α-carbon of this side chain, such as pregnenolone, inhibit growth at a concentration of as little as 1 ppm. Respiration is also inhibited by pregnenolone at this level .     

有害赤潮藻对浮游动物影响的研究进展

有害赤潮藻对浮游动物的影响在赤潮危害的研究中越来越受到关注,本文综述了有害赤潮藻对浮游动物的毒害作用,主要表现为影响浮游动物的存活和生长,降低母体的产卵力、卵的受精率或受精卵的孵化率以及减慢胚胎发育或造成畸形,影响幼体的正常发育,抑制浮游动物的摄食和改变其正常行为等;这些毒害作用主要是由赤潮藻产生的藻毒素或其它一些胞外渗出物通过降低浮游动物对食物的利用率、造成生理损伤、破坏细胞膜、降低亲体产生的配子质量、抑制有丝分裂和胚胎发育等造成的．某些赤潮藻营养成分单一如缺乏多不饱和脂肪酸,也会对浮游动物的生长繁殖产生影响．     

Biological decolorization of dye solution containing Malachite Green by microalgae Cosmarium sp

The potential of Cosmarium species, belonging to green algae, was investigated as a viable biomaterial for biological treatment of triphenylmethane dye, Malachite Green (MG). The results obtained from the batch experiments revealed the ability of algal species in removing dye. The effects of operational parameters (temperature, pH, dye concentration and algal concentration) on decolorization were examined. Optimal initial pH was determined 9. The stability and efficiency of the algae in long-term repetitive operations were also examined. Michaelis-Menten kinetics was used to describe the apparent correlation between the decolorization rate and the dye concentration. The optimal kinetic parameters, nu(max) and K(m) are 7.63 mg dye g cell(-1)h(-1) and 164.57 ppm, respectively. All assays were conducted in triplicates.     

镜泊湖藻类生长和湖泊富营养化预测初探

作者在分析了影响镜泊湖藻类生长的主要因素的基础上,建立了镜泊湖藻类生长模型,利用实验数据和有关资料对镜泊湖藻类生长和湖泊富营养化趋势迸行了预测。作者认为：在镜泊湖藻类的生长季节（５—１０月）,Ｎ浓度始终不是主要限制因子;在藻类生长旺盛的７、８两月,Ｐ浓度成为主要限制因子;在５、６、９、１０四个月中,Ｐ浓度和温度均可能成为主要限制因子,但随着Ｐ浓度的提高,温度成为主要限制因子,客观上河湖泊富营养化的发展起着遏制作用。通过检验,本文模型的输出能反映镜泊湖藻类生物量随时间变化的一般规律。     

Mitigation of adverse effects of rising CO2 on a planktonic herbivore by mixed algal diets

Putative future increase in atmospheric CO₂ is expected to adversely affect herbivore growth due to decrease in contents of key nutrients such as nitrogen and phosphorus (P) relative to carbon in primary producers including plant and algal species. However, as many herbivores are polyphagous and as the response of primary producers to elevated CO₂ is highly species-specific, effects of elevated CO₂ on herbivore growth may differ between feeding conditions with monospecific and multiproducer diets. To examine this possibility, we performed CO₂ manipulation experiments under a P-limited condition with a planktonic herbivore, Daphnia , and three algal species, Scenedesmus obliquus (green algae), Cyclotella sp. (diatoms) and Synechococcus sp. (cyanobacteria). Semibatch cultures with single algal species (monocultures) and multiple algal species (mixed cultures) were grown at ambient (360 ppm) and high CO₂ levels (2000 ppm) that were within the natural range in lakes. Both in the mono- and mixed cultures, algal steady state abundance increased but algal P : C and N : C ratios decreased when they were grown at high CO₂. As expected, Daphnia fed monospecific algae cultured at high CO₂ had decreased growth rates despite increased algal abundance. However, when fed mixed algae cultured at high CO₂, especially consisting of diatoms and cyanobacteria or the three algal species, Daphnia maintained high growth rates despite lowered P and N contents relative to C in the algal diets. These results imply that algal diets composed of multiple species can mitigate the adverse effects of elevated CO₂ on herbivore performance, although the magnitude of this mitigation depends on the composition of algal species involved in the diets.     

Shifting nutrient-mediated interactions between algae and bacteria in a microcosm: evidence from alkaline phosphatase assay

The impacts of different nutrient additions (N + P, N + P + C, 4N + P, 4N + P + C, N + 2P) on the growth of algae and bacteria were studied in a microcosm experiment. Since alkaline phosphatase activity (APA) provides an indication of phosphorus deficiency, the higher value for algal APA in the treatments with excess nitrogen and for bacterial APA in the treatments with excess carbon suggested that, algal and bacterial phosphorus-limited status were induced by abundant nitrogen and carbon input, respectively. Bacterial phosphorus-limited status was weakened due to higher bacterial competition for phosphorus, compared to algae. In comparison with the bacterial and specific bacterial APA, higher values of algal and specific algal APA were found, which showed a gradual increase that coincided with the increase of chlorophyll a concentration. This fact indicated not only a stronger phosphorus demand by algae than by bacteria, but also a complementary relationship for phosphorus demand between algae and bacteria. However, this commensalism could be interfered by glucose input resulting in the decline of chlorophyll a concentration. Furthermore, the correlation between bacterial numbers and chlorophyll a concentration was positive in treatments without carbon and blurry in treatments with carbon. These observations validate a hypothesis that carbon addition can stimulate bacterial growth justifying bacterial nutrient demand, which decreases the availability of nutrients to algae and affects nutrient relationship between algae and bacteria. However, this interference would terminate after algal and bacterial adaption to carbon input.     

Antibiotic treatment enhances C2 toxin production by Alexandrium tamarense in batch cultures

The effects of a mixture of penicillin G and streptomycin on the growth and C2 toxin production of a marine dinoflagellate, Alexandrium tamarense CI01, were investigated to determine if antibiotic treatment would increase the toxin yield of the cultured algae in batch cultures. Algal growth and toxin production were both enhanced markedly when the culture was supplemented with the antibiotics, each at an initial concentration of 100 unit ml⁻¹ in medium,² but were severely inhibited when the concentration was 500 unit ml⁻¹ or higher. Short-term pretreatment of algal inocula with the antibiotics at 100, 500, and 1000 unit ml⁻¹ all produced the enhancing effects on the algal cultures in an autoclaved medium. A prolonged antibiotic pretreatment of the algal culture followed by repeated sterile cultivation resulted in an algal culture free of cultivable bacteria. This “drug-treated” culture became more resistant to the toxicity and more responsive to the enhancing effects of the antibiotics. Our results indicated that the antibiotics can enhance growth and C2 toxin productivity not only through their inhibition of the growth of bacteria that compete for nutrients with the coexisting algae, but also through their direct effects on the physiology of the algae. Supplementation of the two antibiotics therefore is an efficient way to increase the yield of C2 toxin in the production cultures of A. tamarense CI01.