苄嘧磺隆对蛋白核小球藻的生长效应研究

通过不同浓度的苄嘧磺隆对蛋白核小球藻的96h急性毒性试验，研究苄嘧磺隆对蛋白核小球藻（Chlorella pyrenoidosa）的生长效应。结果表明，低浓度苄嘧磺隆（<1mg/L）具有刺激藻细胞生长的作用，其叶绿素含量和蛋白质含量均有明显的增加；高浓度的苄嘧磺隆(>5mg/L)抑制藻的生长，藻细胞叶绿素含量和可溶性蛋白质含量随药剂浓度增加而明显下降，且表现出较好的计量－效应关系，其对蛋白核小球藻的96h-EC50值为15.7mg/L。     

氧化锌和二氧化钛纳米颗粒对淡水绿藻的单一及联合毒性研究

以氧化锌纳米颗粒(ZnO NPs)和二氧化钛纳米颗粒(TiO_2 NPs)为研究对象,考察了ZnO NPs和TiO_2 NPs对两种淡水绿藻(斜生栅藻和蛋白核小球藻)的单一及联合毒性。结果表明:在不同的暴露时间下,ZnO NPs对淡水绿藻的生长抑制毒性均明显高于TiO_2 NPs,且溶解释放的Zn~(2+)在ZnO NPs对斜生栅藻毒性效应中的贡献高于其在ZnO NPs对蛋白核小球藻毒性效应中的贡献。ZnO NPs和TiO_2 NPs对斜生栅藻的联合毒性大于其对蛋白核小球藻的联合毒性,且ZnO NPs的毒性在二元混合物毒性中占主要贡献。ZnO NPs与TiO_2 NPs对斜生栅藻的联合毒性作用方式在混合暴露浓度小于1 mg·L~(-1)时表现为加和,而在混合暴露浓度大于1mg·L~(-1)时表现为拮抗;二元混合物对蛋白核小球藻在24 h的联合毒性作用方式表现为协同,而在48 h和72 h的联合毒性作用方式表现为拮抗。不同的暴露时间下独立作用模型对二元混合物毒性的预测能力均强于浓度加和模型,另外ZnO NPs和TiO_2 NPs对淡水绿藻的联合毒性机制与纳米颗粒诱导活性氧物种生成,引起藻细胞氧化应激有关。     

十六烷基三甲基溴化铵对蛋白核小球藻的毒性效应

以蛋白核小球藻为受试物,分别设0(CK)、0.06、0.12、0.18、0.24、0.30、0.36 mg/L十六烷基三甲基溴化铵(CTAB)处理,考察CTAB对藻生长和生化指标的影响,分析其致毒机理。结果表明:CTAB对蛋白核小球藻96 h EC50值为0.17 mg/L;藻细胞叶绿素a、水溶性蛋白质含量及超氧化物歧化酶(SOD)活性随CTAB浓度增加呈先升后降趋势,当CTAB剂量≤0.06 mg/L时,叶绿素a含量略微上升,>0.06 mg/L时,叶绿素a含量急剧下降;CTAB剂量≤0.24 mg/L处理下蛋白质含量增加,CTAB剂量≥0.30 mg/L处理时水溶性蛋白含量低于对照组;除剂量≤0.06 mg/L处理外,SOD活性随CTAB剂量的增大呈下降趋势;脂质过氧化丙二醛(MDA)含量则随CTAB浓度增加逐渐上升;CTAB对蛋白核小球藻的致毒机理为通过破坏细胞膜完整性,抑制SOD活性,导致MDA含量持续上升。     

Effects of Chlorine Dioxide Gas on Postharvest Physiology and Storage Quality of Green Bell Pepper （Capsicum frutescens L. var. Longrum）

The effects of treatment of chlorine dioxide (ClO2) gas on postharvest physiology and preservation quality of green bell peppers were studied. Green bell peppers were collected in bags and treated with 0, 5, 10, 20, and 50 mg L-1 ClO2 gas at 10 ± 0.5℃ for over 40 d, and the changes in postharvest physiology and preservation quality of the peppers were evaluated during the storage. The inhibition of rot of the peppers was observed for all the tested ClO2 gas treatments. The rot rates of the treated samples were 50% lesser than those of the control after day 40 of storage. The highest inhibitory effect was obtained after 50 mg L-1 ClO2 gas treatment, where the peppers did not decay until day 30 and showed only one-fourth of the rot rate of the control at day 40 of storage. The respiratory activity of the peppers was significantly (P ＜ 0.05) inhibited by 20 and 50 mg L-1 ClO2 treatments, whereas no significant effects on respiratory activity were observed with 5 and 10 mg L-1ClO2 treatments (P＞ 0.05). Except for 50 mg L-1 ClO2, malondialdenyde (MDA) contents in the peppers treated with 5,10, or 20 mg L-1 ClO2 were not significantly (P＞0.05) different from those in the control. Degradation of chlorophyll in the peppers was delayed by 5 mg L-1 ClO2, but promoted by 10, 20, or 50 mg L-1 ClO2. The vitamin C content, titratable acidity,and total soluble solids of the peppers treated by all the tested ClO2 gas did not significantly change during the storage.The results suggested that ClO2 gas treatment effectively delayed the postharvest physiological transformation of green peppers, inhibited decay and respiration, maintained some nutritional and sensory quality, and retarded MDA accumulation.     

Study on Agrobacterium-Mediated Transformation of Pepper with Barnase and Cre Gene

This study was designed to control plant fertility by cell lethal gene Barnase expressing at specific developmental stage and in specific tissue of male organ under the control of Cre/lox system, for heterosis breeding of chili pepper （Capsicum annuum L.）. Chili pepper inbred lines （A, D, E, and I） were transformed with Cre gene and Barnase gene situated between loxp, separately, by means of Agrobacterium co-culture. In this study, we had established a high transformation system by extensive study of affecting factors including genotype, selection of marker, and lethal dose. Cotyledon with petiole from 9-11-day-old seeding was pre-cultured on media MR[MB（MS mineral＋vitamine B5）＋BA（6-Benzyladenine） 5.0 mg·L^-1 ＋IAA（indoleacetic acid） 1.0 mg·L^-1＋GA3（gibberellic acid） 1.0mg·L^-1＋sucrose 3%＋agar 6.5g·L^-1] for 2d. The explants were infected by Agrobacterium tumefaciens when their OD600（optical density at 600 nm）reached 0.6-0.9. After co-cultured for 4-5 d on media MC [MB＋BA5.0 mg·L^-1＋IAA 1.0 mg·L^-1 ＋GA3 1.0 mg·L^-1＋sucrose 3% ＋agar 6.5 g·L^-1＋AS （acetosyringone） 200μmol·L^-1, these cotyledons with petiole were cultured on selective differentiation medium in the media MT[MB medium supplemented with BA [5.0 mg·L^-1＋ IAA 1.0 mg·L^-1＋ GA3 1.0 mg·L^-1＋ AgNO3 5.0 mg·L^-1＋ CW （coconut water） 5% ＋ Km （kanamycin） 65 mg·L^-1＋ Cb （carbenicillin） 500 mg·L^-1＋ 3% sucrose ＋ agar 6.5 g·L^-1].The Kmr （kanamycin resistant） bud rosettes were elongated on selective elongation medium and rooted on rooting medium. PCR and Southern blotting analysis of Kmr plantlet indicated that the foreign genes had been integrated into the genome of pepper. The transgenic plants with Cre gene developed well, blossomed out, and set fruit normally. The transgenic plants with Barnase gene grew well with normal appearance of flower, but they showed different fertility from complete sterility, partial sterility to complete fertility, and similar results were obtained from in vitro pollen germination experiments.     

壬基酚对四尾棚藻生长及群体形成的影响

选取水体中广泛存在的壬基酚为代表,研究其对四尾栅藻生理特性及群体形成的影响。实验设置6个暴露组(0.63、1.02、1.65、2.67、4.32和7.00 mg·L-1)和1个对照组(0 mg·L-1),测定了96 h内四尾栅藻细胞密度、叶绿素a含量、胞外多糖合成、最大光能转化效率(Fv/Fm)以及群体形态等变化。结果表明,四尾栅藻起始细胞密度6.64×105 cells·m L-1下,壬基酚对四尾栅藻细胞密度的EC50为2.05 mg·L-1;随着壬基酚质量浓度的提高,四尾栅藻的叶绿素a含量和Fv/Fm下降,四尾栅藻的生长受到抑制,但细胞胞外多糖含量增多,导致细胞间黏性增强,同时双细胞和多细胞(≥3个)群体占总细胞比例上升。     

Nitrogen Dioxide-Induced Responses in Brassica campestris Seedlings： The Role of Hydrogen Peroxide in the Modulation of Antioxidative Level and Induced Resistance

This article investigates the responses of Brassica campestris seedlings to an acute level of nitrogen dioxide (NO₂) exposure in a plant growth chamber, and examines whether pretreating plants with hydrogen peroxide (H₂O₂) will alleviate NO₂-caused injury. Twenty-eight-day-old B. campestris plants sprayed with 10 mmol L⁻¹ H₂O₂ aqueous solution (corresponding to approximate 1.0 mg H₂O₂ per single plant) were exposed to different concentrations of NO₂ (0.25, 0.5, 1.0, and 2.0 μL L⁻¹, respectively) for 24 h under controlled environment. To measure the plant biomass, the plants were fumigated with the same NO₂ concentrations as mentioned above for 7 h per day (8.00-15.00) for 7 days. As a control, charcoal filtered air alone was applied. Data were collected on plant biomass, total chlorophyll, photosynthetic rate, stomatal conductance, nitrate and nitrate reductase (NR), antioxidative enzymes, ascorbate (ASA), and malondialdehyde (MDA), immediately after exposure. The results showed that exposure to a moderate dose of NO₂ (e.g., 0.25 μL L⁻¹) had a favorable effect on plants, and the dry weight of the above-ground part increased, whereas the exposure to high NO₂ concentrations (e.g., 0.5 μL L⁻¹ or higher) caused a reduction in the plant biomass and the total chlorophyll, when compared with the control. In addition, at 0.5 μL L⁻¹ or higher NO₂ concentrations, prominent increases in the MDA level and superoxide dismutase (SOD) and NR activities were observed. Exposure to 1 μL L⁻¹ and higher NO₂ resulted in necroses appearing on older leaves, and an increase in catalase (CAT) activity, decrease in ASA content, increased accumulation of NO₃, and reduction in photosynthesis, when compared with the controls. No changes were detected in stomatal conductance under NO₂ fumigation. The pretreatment with 10 mmol L⁻¹ H₂O₂ alleviated significantly NO₂-caused biomass decrease and photosynthetic inhibition when compared with H₂O₂-untreated plants. Under NO₂ fumigation, further induction in SOD and CAT activities occurred in H₂O₂ treated plants when compared with H₂O₂-untreated plants. The effect of NO₂ on the ASA and MDA contents was also absent in H₂O₂-treated plants. However, the H₂O₂ treatment did not alter the nitrate content and NR activity in plants under NO₂ fumigation. The H₂O₂ treatment caused a lower rate of stomatal conductance. Taken together, these data suggest that fumigation with an acute level of NO₂ causes oxidative damage to B. campestris seedlings. The H₂O₂ pretreatment markedly protects plants against NO₂ stress and this may be associated with inducible antioxidative level. NO₂ fumigation contributes, at least in part, to the enhanced levels of nitrate in B. campestris leaves.     

卡马西平对小球藻生长的影响和氧化损伤

为了考察药品及个人护理品(Pharmaceuticals and Personal Care Products,PPCPs)对水生生物及生态环境的影响,以典型的PPCPs化合物卡马西平(Carbamazepine,CBZ)为目标化合物,研究其对普通小球藻(Chlorella)的生长、叶绿素含量、超氧化物歧化酶(Superoxide Dismutase,SOD)活性、过氧化氢酶(Catalase,CAT)活性和丙二醛(Malondialdehyde,MDA)含量的影响。结果表明,CBZ对小球藻的96 h半最大效应浓度(EC_(50))为154.42 mg·L~(-1),对小球藻具有一定的毒性作用,能抑制小球藻的生长。CBZ影响小球藻的叶绿素含量,低浓度(0.1 mg·L~(-1))的CBZ对小球藻的叶绿素a和b的含量有抑制作用,使其分别降低到2.16 mg·L~(-1)和0.38 mg·L~(-1),随着CBZ浓度的升高,抑制作用逐渐减弱;小球藻SOD的活性随CBZ浓度的升高表现出先激活后抑制的状态,CAT活性表现出中低浓度激活的状态;CBZ对MDA含量的影响较弱,处理组含量在2.06~2.32 nmol·g~(-1)范围之间,略高于对照组。由冗余分析(RDA)可知,CBZ对小球藻CAT、SOD活性和叶绿素a含量的影响更显著。     

四尾栅藻对重金属镉胁迫的响应

通过不同浓度镉(0、0.5、1、3、5、7 mg·L-1)胁迫实验,对四尾栅藻(Scenedesmus quadricauda)的生长、色素、过氧化氢、超氧化物阴离子、可溶性蛋白含量进行分析,研究四尾栅藻对重金属镉胁迫的响应情况。实验显示:镉胁迫使四尾栅藻的生长受到抑制,在较高镉浓度(3~7 mg·L-1)下四尾栅藻的生长受到强烈抑制;随着镉浓度的上升,色素(叶绿素a、叶绿素b、类胡萝卜素)含量逐渐减少,过氧化氢、超氧化物阴离子含量增加,过氧化氢含量在镉浓度为5~7 mg·L-1时显著增多,超氧化物阴离子含量在镉浓度为7mg·L-1时显著增加;可溶性蛋白含量先增加,并在镉浓度为1 mg·L-1时达到最大值,之后随着镉浓度的上升而逐渐减小。研究结果表明,四尾栅藻对重金属镉有较好的耐受性(可以耐受1 mg·L-1的镉)。     

斜生四链藻对水中四环素的胁迫响应及去除作用

四环素由于其低生物降解性和水溶性而在水环境中持续存在,对生态环境安全造成较高的潜在风险。为探讨水环境中残留的四环素与藻类的相互作用,以斜生四链藻为研究对象,考察了斜生四链藻对水中不同浓度四环素(0.5、1.0、1.5、2.5、4.0和6.0 mg·L^-1)的胁迫响应及去除作用。结果表明,各浓度四环素处理组均对斜生四链藻的生长产生抑制作用,最高抑制率达到了72.99%,四环素对斜生四链藻的半数效应质量浓度(96 h-EC50)和抑制效应为80%质量浓度(96 h-EC80)分别为2.46和6.9 mg·L^-1。在相同浓度四环素胁迫下,斜生四链藻的光合色素含量和Fv/Fm值呈现出和斜生四链藻细胞密度变化相同的趋势,与对照组相比,6.0 mg·L^-1浓度处理组中斜生四链藻的叶绿素a、叶绿素b和类胡萝卜素含量在96 h的抑制率分别是87.32%、66.91%和87.58%,Fv/Fm值降幅达到了77.4%。在低、中、高浓度四环素(0.5、1.5和6.0 mg·L^-1)胁迫下暴露96 h,斜生四链藻的丙二醛(...     

三嗪类农药复合污染物对蛋白核小球藻的联合毒性作用评估

为探讨复合污染的三嗪类农药对非靶标生物的联合毒性作用,以苯嗪草酮(Metamitron, Met)、草净津(Bladex, Bla)和特丁通(Terbumeton, Ter)为目标污染物,以蛋白核小球藻(Chlorella pyrenoidosa, C. pyrenoidosa)为指示生物,分别应用直接均分射线法和均匀设计射线法设计二元及三元混合物体系,采用微板毒性分析法系统测定3种农药及其混合污染物对C. pyrenoidosa的时间-浓度-效应数据,应用浓度加和(Concentration addition, CA)为标准参考模型分析混合物毒性相互作用,应用二维和三维等效图表征混合物联合毒性作用规律,并同步分析C. pyrenoidosa中叶绿素a含量变化,进一步评价农药及其混合物对小球藻的毒性效应。结果表明:农药及其混合物对C. pyrenoidosa的毒性数据可用Logit函数较好拟合,3种农药的毒性顺序为BlaTerMet;依据CA模型,二元混合物的毒性相互作用整体上呈现为加和作用向协同作用的转变,二维等效图显示3组二元混合物体系在半数效应浓度均具有较强的协同作用;农药三元混合物体系的5条射线均呈现加和作用,且不随暴露时间延长发生改变,三维等效图法与CA模型的分析结果基本一致;叶绿素a含量减少率与其浓度-效应曲线变化趋势基本一致。     

Somatic Embryogenesis and Plant Regeneration from Two Recalcitrant Genotypes of Gossypium hirsutum L.

An improved protocol has been developed for somatic embryogenesis and plant regeneration of recalcitrant cotton cultivars. High callus frequencies and embryogenic tissue were developed in MSB medium supplemented with gradient concentrations of KT and 2,4-D, their concentration decreasing from 0.1 to 0.01 mg L⁻¹. Somatic embryos were successfully incubated in 1/2 macronutrient MSB suspension supplemented with 0.5 g L⁻¹ glutamine and 0.5 g L⁻¹ asparagine. Decrease in macronutrient concentration of MSB significantly alleviated browning and was beneficial to suspension cells. Transformation of somatic embryos into plants was induced in MSB medium supplemented with 3% sucrose, 0.5 g L⁻¹ glutamine, 0.5 g L⁻¹ asparagine, and 6.0 g L⁻¹ agar. The effect of sucrose as carbohydrate was better than that of glucose for plant germination. Using this protocol, regenerated plantlets from the CCRI521 and Zhongzhi86-6 reached to as much as 19.6 and 18.5% somatic embryos, respectively.     

钇(Y3+)对缺氮、缺磷胁迫下铜绿微囊藻生长和生理特性及藻毒素释放的影响

为探究稀土元素钇(Y~(3+))对缺氮、缺磷胁迫下铜绿微囊藻生长的影响,测定了缺素胁迫下不同Y~(3+)浓度时藻的生长量、叶绿素a、可溶性糖、可溶性蛋白含量、抗氧化酶活性(超氧化物歧化酶SOD、过氧化氢酶CAT、过氧化物酶POD)以及丙二醛(MDA)和藻毒素(MC-LR)含量。结果表明:在缺氮、缺磷胁迫下,Y~(3+)对铜绿微囊藻的生长表现出低促高抑的"Hormesis"现象。低浓度Y~(3+)(0.10~0.20 mg·L~(-1))能维持铜绿微囊藻的生长,增强抗氧化酶活性,减轻缺素胁迫造成的损伤;高浓度Y~(3+)(0.50~2.00 mg·L~(-1))则加剧缺氮、缺磷胁迫对藻的迫害,光合色素、可溶性糖及可溶性蛋白含量呈明显的下降趋势,抗氧化酶活性受到抑制,膜质过氧化程度加重,MC-LR含量增加。     

Mechanism of herbicidal action of the component I from Pythium aphanidermatum

The herbicidal mechanism of the components extracted from Pythium aphanidermatum was examined in this study. Component I was isolated using the HPD500 macroporous adsorption resin and HPLC. Its impact on seed germination and plant growth of weeds was determined and the contents of MDA, superoxide anion radical, and the activities of hills and roots were examined. The root length of weed plants was inhibited under illumination while the stem height was inhibited evidently under darkness. The relative electric conductivity of Digitaria sanguinalis and Amaranthus retroflexus under illumination was 94.55 μS·cm⁻¹ and 58.75 μS·cm⁻¹, respectively, whereas that under darkness was 85.25 μS·cm⁻¹ and 36.25 μS·cm⁻¹, respectively. The MDA contents of Digitaria sanguinalis and Chlorella pyrenoidosa were 0.08385 μmol·L⁻¹ and 0.1742 μmol·L⁻¹ under illumination, respectively, while those were 0.0129 μmol·L⁻¹ and 0.01935 μmol·L⁻¹ under darkness, respectively. Simultaneously, superoxide anion radical content was higher under illumination than under darkness. These results showed the photosynthesis was affected by component I extracted from Pythium aphanidermatum.     

不同光质条件及NH4+-N、Cu2+浓度对栅藻处理沼液的影响

将筛选所得耐污能力强的栅藻作为研究对象,研究不同光质条件对栅藻处理沼液的影响,并且以实际沼液废水中NH₄⁺-N、Cu²⁺浓度为参照设置不同浓度,分别考察NH₄⁺-N、Cu²⁺对栅藻生长的影响。结果表明：在白光、蓝光、红光3种光质下,栅藻生物产率分别是0.21、0.04、0.03 g ·L^-1·d^-1,白光条件下栅藻生长相对较好。50 mg·L^-1低浓度NH₄⁺-N下栅藻生长较好,其生物产率优于BG 11培养基,分别为0.20、0.18 g·L^-1·d^-1;500、2000 mg·L^-1高浓度NH₄⁺-N下,藻细胞生长缓慢,生物产率仅为0.12、0.11 g·L^-1·d^-1。在Cu²⁺浓度分别为0.5、1.0、2.0 mg·L^-1的培养液中,藻细胞生物产率分别为0.18、0.15、0.13 g·L^-1·d^-1。一定浓度NH₄⁺-N存在下,栅藻能耐受较高的Cu²⁺浓度。     

氟唑菌苯胺对蛋白核小球藻的立体选择性毒性效应

为了探究氟唑菌苯胺对水生生物的立体选择性毒性效应,测定了氟唑菌苯胺对映体对蛋白核小球藻的急性毒性以及光合色素含量的影响。结果表明,S-氟唑菌苯胺对蛋白核小球藻具有更高的急性毒性,是R-氟唑菌苯胺1.2倍。高剂量暴露浓度下,S-氟唑菌苯胺对小球藻叶绿素a、叶绿素b、类胡萝卜素生物合成的抑制率分别为35%、28%、37%,是R-对映体的2.1、1.9、2.8倍,表明氟唑菌苯胺对蛋白核小球藻的立体选择性急性毒性可能是由于对映体对光合色素生物合成抑制差异造成的。降解实验结果表明低毒对映体R-氟唑菌苯胺被优先降解,第7天时R-氟唑菌苯胺和S-氟唑菌苯胺降解率分别为82.5%和65.8%,EF值为0.12,且对映体构型稳定。研究结果为氟唑菌苯胺水生生态风险评价提供数据支撑,同时为手性农药立体选择性机制研究提供新的思路。     

Induction and Genetic Identification of Embryogenic Calli from Hybrids of Shatian Pummelo

Shatian pummelo （Citrus grandis L. Osbeck cv. Shatian） is an elite variety in China, and the regeneration of the embryogenic callus is difficult. Diploid Shatian pummelo was used as the female and crossed with the allotetraploid somatic hybrid NS （Nova Tangelo ＋ Succari Sweet orange）, [ （ C reticulata Blanco x C. paradisi Macf.） cv. Nova ＋ C sinensis L. Osbeck cv. Succari]. About 90 days after pollination, the embryos obtained from crosses were cultured on the solid media of MT ＋ ME （malt extraction, 500 mg L^-1） and MT ＋ GA3 （1 mg L^-1）. The embryogenic callus was initiated from the embryoids and plantlets＇ hypocotyls and could be subcultured. Flow cytometry and SSR analysis verified that the callus was from the triploid hybrids. The callus had embryogenesis capacity and produced a large number of embryoids on MT ＋Lactose （50 g L^-1） medium after being subcultured for two years. It is comparatively easier to obtain the callus from the hybrid embryo than from Shatian pummelo itself. The callus is valuable for the conservation and utilization of Shatian pummelo.     

苄嘧磺隆对白菜的安全性研究

[目的]为苄嘧磺隆的合理使用提供理论指导。[方法]采用水培法,研究苄嘧磺隆对白菜的安全性。[方法]结果表明,苄嘧磺隆对白菜芽长的安全性大于根长,LC10值分别为0.112 0和0.066 3μg/ml。其对白菜叶片中叶绿素、丙二醛、可溶性糖的含量具有较大的影响,叶绿素含量随药剂浓度的提高呈下降趋势,丙二醛和可溶性糖含量随处理浓度的升高而增加,但不同浓度之间增加的幅度不同。[结论]田间使用苄嘧磺隆采用茎叶处理法,并且选择最佳使用时期和使用剂量,以免对后茬白菜产生药害。     

不同氮磷浓度对蛋白核小球藻砷富集和转化的影响

氮(N)、磷(P)是影响蛋白核小球藻生长的重要因素,通过改变培养液中N、P的浓度,可能实现对蛋白核小球藻富集砷(As)进行调控。为探讨N、P浓度对这种微藻吸收As的影响是否与其生长变化有关,采用室内培养实验,首先研究不同N、P浓度对蛋白核小球藻生长的影响;进而选择不影响小球藻生长的N(247、24.7 mg·L-1)、P(6、0.6 mg·L-1)浓度组合,设置0.8、8 mg·L-1的亚砷酸盐(As3+)和砷酸盐(As5+)处理3 d,研究N、P浓度对小球藻As富集和转化的影响。结果表明,当P浓度为6 mg·L-1时,N浓度降低到24.7 mg·L-1不会影响小球藻对As3+和As5+的富集及其胞内As形态的转化;而当N浓度为247 mg·L-1时,P浓度降低到0.6 mg·L-1则会显著增加小球藻对As3+和As5+的吸收和富集,藻细胞内As5+还原、甲基化和外排也显著增强。因此,在不影响小球藻细胞生长的条件下,P对其As富集和转化过程的影响比N更为显著。     

锌和铁对浅水湖泊中浮游植物复苏影响研究——以玄武湖为例

选取冬季12月的玄武湖水样,调整培养液的起始金属离子浓度(锌:0、3.25×10-4、3.25×10~(-3)、3.25×10~(-2) mg·L~(-1);铁:0、2.80×10-4、2.80×10~(-3)、2.80×10~(-2)mg·L~(-1)),探讨金属离子锌、铁对浮游植物复苏过程中群落结构的影响。结果表明:当锌为3.25×10~(-2)mg·L~(-1)时,蓝藻的复苏受到明显的抑制,绿藻及硅藻的生长受到胁迫作用,Fv/Fm值分别降至0.40、0.30、0;当铁浓度高于2.80×10~(-2)mg·L~(-1)时,蓝藻的复苏同样受到抑制,Fv/Fm值降为0.45,而绿藻和硅藻的Fv/Fm分别为0.33和0.07。高铁浓度下复苏后的浮游植物以蓝藻门的微囊藻为主,绿藻门的栅藻次之;高浓度锌胁迫下复苏后的浮游植物主要为绿藻门的栅藻,其次是绿藻门的小球藻,再后是蓝藻门的微囊藻。