大叶藻对氮磷营养盐的吸收动力学特征

营养盐是影响海草生长的关键因子, 目前有关海草不同组织对不同形式氮和磷的吸收特征尚不明确。该研究通过利用海草地上和地下组织分隔培养装置, 设置不同的氨态氮、硝态氮和磷酸盐浓度, 探究了大叶藻(Zostera marina)植株及其地上和地下组织对氮磷营养盐的吸收动力学特征。结果显示: (1)大叶藻对氮磷的吸收符合饱和吸收动力学特征, 吸收速率和水体氮磷浓度可用米式方程描述; (2)大叶藻植株对NH₄⁺-N的最大吸收速率(V_max, 52 μmol·g^-1·h^-1)显著高于其对NO₃^--N的V_max (39 μmol·g^-1·h^-1); (3)大叶藻地上组织和地下组织均可吸收氮磷, 但地上组织对氨态氮、硝态氮、磷酸盐的V_max分别为43.1、30.5和15.6 μmol·g^-1·h^-1, 为地下组织的2.6、1.2和6倍。结果表明, 大叶藻对氨态氮的吸收能力高于硝态氮, 且对氮磷的吸收可能主要依赖地上组织(叶片)。结果为查明大叶藻对氮磷的吸收利用机制及评估大叶藻的海洋生态效应提供了理论依据。     

广西北海竹林三种海草种群生物量和生产力研究

采用收获法和改进的Zieman标记法,测定了2007年11月广西北海竹林海草床二药藻(Halodule uninervis)、矮人叶藻(Zostera japonica)和喜盐草(Halophila ovalis)三个种群的生物量和叶片生产力.结果表明:(1)总生物量是二药藻(198.99±22.19 g DW m-2)>矮大叶藻(184.89±21.24gDW m-2)>喜盐草(110.71 ±12.23 g DW m-2);(2)二药藻、矮大叶藻、喜盐草地下部分生物量占各自总生物量的比例分别为69.68%,47.59%,56.33%;(3)幼叶、成熟叶、衰老叶的生物量分别是矮大叶藻9.99 ±0.33 g DW m-2,26.24 ±2.34g DW m-2,38.02±1.94g DW m-2;喜盐草7.31±1.50g DW m-2,21.19±6.25 g DW m-2,19.85±3.05 g DW m-2:(4)矮大叶藻的叶片生产力(2.05±0.15 g DW m-2·d-1)大于二药藻(0.34±0.37 g DW m2·d-1).提出了根据幼叶和衰老叶生物量比值预测种群消长的建议.     

阿特拉津降解菌株的分离和鉴定

从农药厂废水中分离到6株能以除草剂阿特拉津为唯一氮源生长的细菌,即假单胞菌（Pseudomonas spp,.)AD1,AD2和AD6,土壤杆菌（Agrobacterium sp.)AD4,黄单胞菌（Xanthomonas sp.)AD5,欧氏菌（Erwinia sp.)AD7,AD1菌株能使无机盐培养基中的0．3g/L阿特拉津在72h内降解99．9％,当以AD1,AD2,AD4,AD5,AD6和AD7菌株的总DNA为模板进行PCR扩增时,除AD2菌株以外,均得到了与献报道的假单胞菌ADP菌株的阿特拉津氯水解酶基因（atzA)同源的PCR产物。     

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。     

有机磷农药在水生态系中生物净化机理研究——3.对硫磷及其降解产物对栅藻光合作用的影响和模拟藻菌系统中对硝基酚的降解

对硝基酚对栅藻光合放氧有明显抑制作用,半抑制浓度在16毫克/升左右;对硝基酚钠对栅藻光合放氧和CO2同化的抑制作用十分一致,它们的半抑制浓度分别在54毫克/升和52毫克/升左右。实验室证明对硝基酚在水体中主要是由细菌分解,藻类起供氧作用。一旦藻类的光合放氧受到抑制,细菌对对硝基酚的好气性降解能力也消失。对硫磷和二乙基硫代磷酸钾对栅藻光合放氧无明显抑制作用。       

基因工程菌对阿特拉津的生物转化及其影响因素

研究考察了基因工程菌转化阿特拉津的共代谢碳源、转化动力学和影响因素。结果表明,作为共代谢碳源,葡萄糖优于乙酸盐,碳源浓度对转化影响不大,对工程菌生长影响显著。阿特拉津比转化速率与工程菌初始密度无关,与阿特拉津初始浓度有关,用Monod方程拟合转化动力学,求得方程参数为V_(max)=0．168/h,Ks= 30．49mg/L。降低温度会显著降低阿特拉津比转化速率;偏碱性的条件下,阿特拉津转化率较高,酸性条件严重抑制阿特拉津转化;盐度在一定范围内不影响转化活性;Co~(2 )、Fe~(2 )、Fe~(3 )和Zn~(2 )促进阿特拉津转化,Mn~(2 )、Ni~(2 )和Cu~(2 )抑制阿特拉津转化。菌体细胞对阿特拉津的吸附和转化作用呈正相关关系。     

阿特拉津降解菌株AD111的分离鉴定及其降解特性

【背景】玉豆轮作过程中,玉米田中长残留除草剂阿特拉津易对下茬大豆作物产生不良影响。【目的】从黑龙江省安达市的农田土筛选一株能适应该土壤环境生长的阿特拉津降解菌并研究其降解特性。【方法】利用富集培养法,分离、筛选一株阿特拉津高效降解菌并结合外观形态、生理生化及16SrRNA基因序列测定对其进行鉴定,通过单一变量法设置不同的碳源、pH、温度和阿特拉津浓度,研究降解菌株最佳发酵及降解条件。【结果】得到一株在BSM-G中能够以阿特拉津为唯一氮源生长的高效阿特拉津降解菌AD111,鉴定为马德普拉塔无色小杆菌(Achromobacter marplatensis)。菌株AD111降解阿特拉津的最适温度为35℃,最适pH为8.0,最佳碳源为蔗糖,24 h内对浓度为50 mg/L的阿特拉津降解率达到99.7%,对300 mg/L的阿特拉津降解率达到81.9%。【结论】降解菌AD111具有较好的环境适应及阿特拉津降解能力,为解决黑龙江偏碱土壤中阿特拉津残留提供了良好的候选菌株。     

不同磷条件下塔玛亚历山大藻氮的生态幅

藻类氮的生态辐是指在一定氮浓度范围内藻类能生长和繁殖的浓度范围。它由藻类生长的最佳氮浓度、氮适宜生长范围和氮耐受限度构成。为了定量计算藻类的氮生态幅,在室内培养条件下,研究了低磷(0.48 μmol/L)、中磷(0.97 μmol/L)和高磷(1.45 μmol/L)3种不同磷起始浓度条件下不同氮对塔玛亚历山大藻细胞数和最大比生长率的影响,依据Shelford耐受性定律建立了塔玛亚历山大藻生长的氮耐受性模型,并得到了藻类生长的最佳氮浓度、氮适宜生长范围和氮耐受范围的定量表达。结果表明,在低磷、中磷和高磷条件下,当氮浓度小于适合藻类生长的最佳氮浓度时,藻类细胞数和最大比生长率均随着氮浓度的增大而增大;当氮浓度大于适合藻类生长的最佳氮浓度时,藻类细胞数和最大比生长率均随着氮浓度的增大而减小。藻类生长的氮耐受性模型与谢尔福德耐受定律较为吻合,定量得到在低磷、中磷和高磷培养条件下塔玛亚历山大藻的最佳氮浓度分别为30.36、62.07和77.85 μmol/L;氮适宜生长范围分别为18.30-42.42、37.71-86.43和41.52-114.18 μmol/L;氮耐受限度分别为6.24-54.48、13.35-110.79和5.19-150.51 μmol/L。研究显示不同磷起始浓度条件下,藻类的氮生态幅也不相同。     

扑草净对远志幼苗根系活力及氧化胁迫的影响

以远志(Polygala tenuifolia Willd.)为材料,应用组织化学和生物化学的方法研究不同浓度扑草净(0—400 mg/L)对远志幼苗生长、根系活力、膜脂过氧化、活性氧含量及抗氧化酶活性等的影响。10 mg/L扑草净对远志幼苗根系活力、细胞膜完整性及活性氧的积累几乎无显著影响,而25—400 mg/L扑草净处理则显著增加活性氧的积累,明显抑制根系活力且破坏细胞膜完整性;上述结果进一步被膜脂过氧化、质膜完整性、活性氧产生(O.2-和H2O2)的非损伤组织化学染色所证明。远志幼苗可通过多种抗氧化酶(SOD、POD、CAT、APX等)和非酶抗氧化剂(如脯氨酸)的相互协调作用,清除低浓度扑草净胁迫诱发产生的活性氧,减轻对细胞的伤害。研究结果表明,发芽期是远志对扑草净处理的敏感时期,较为安全的扑草净临界浓度为10 mg/L;25mg/L扑草净处理即引起远志幼苗氧化胁迫和膜脂过氧化,使细胞膜的完整性受到破坏,根系活力下降,抑制了远志幼苗的生长发育。该研究为远志抗除草剂胁迫机制及其栽培过程中除草剂的安全合理使用提供理论依据。     

大型海藻裂片石莼藻粉对赤潮异弯藻光合作用抑制的研究

为了探究大型海藻裂片石莼(Ulva fasciata)防治赤潮的可行性,研究将赤潮异弯藻(Heterosigma aka-shiwo)分别暴露在浓度为0.6、1.2、2.4和4.8 g/L的裂片石莼藻粉中,观察赤潮异弯藻光合系统的响应.实验用植物效率分析法测定了赤潮异弯藻的光合效率,用透射电子显微镜法观察了赤潮异弯藻叶...     

Seawater-resistant, non-spherical protoplasts from seagrass leaves

Two distinct types occurred among enzymatically isolated protoplasts from leaves of eelgrasses ( Zostera marina L., Z. japonica Ascherson and Phyllospadix iwatensis Makino). Spherical protoplasts with a smooth cell membrane were obtained only from young leaf tissues at the basal portions of blades protected from seawater by tightly enclosing sheaths. Non-spherical protoplasts had a highly invaginated cell membrane and were obtained from mature leaf blades, where the cells also in situ have this type of membrane. The protoplasts from mature leaves were rather rigid in shape and resistant to wide ranges of osmotic potential and salinity without change in their non-spherical shape, while the spherical protoplasts were rapidly destroyed in seawater. Detergents lysed the spherical protoplasts but not the non-spherical ones, suggesting that the highly invaginated enclosing structures of the non-spherical protoplasts contained detergent-resistant materials. Thus, the seagrass leaf cells develop seawater resistance, and this change alters the nature of the enclosing structures during the growth of the leaf blades. The non-membranous enclosing structures and their characteristic materials in the mature leaf cells remain to be defined.     

海藻多糖的单糖组成对体外抗氧化活性的影响

比较广西北部湾石莼(Ulva lactuca L.)、海带(Laminaria japonica)、裙带菜(Undaria pinnatifida Surin-gar)、紫菜(Porphyra)的单糖组成及抗氧化活性的差异,揭示多糖结构与其体外抗氧化活性的关系。利用PMP柱前衍生化HPLC分析海藻多糖的单糖组成,采用羟自由基清除试验、超氧阴离子自由基清除试验及DPPH自由基清除试验指征其体外抗氧化活性,结果表明,4种海藻多糖的单糖组成在主成分空间分布离散,石莼及紫菜主要由葡萄糖组成,海带主要由甘露糖组成,裙带菜则主要由半乳糖组成;其体外抗氧化活性存在显著差异,裙带菜多糖对DPPH的清除能力(半抑制浓度IC₅₀值为0. 56±0. 02 mg/mL)显著高于其他3种海藻多糖;石莼、裙带菜与海带对羟自由基均有较强的清除活性,而紫菜多糖对羟自由基的清除能力较差(IC₅₀值为26. 59±0. 98mg/mL);石莼与裙带菜对超氧阴离子的清除活性较强,显著高于海带与紫菜,其中石莼显著高于裙带菜,IC₅₀值分别为1. 61±0. 17、2. 73±0. 06 mg/mL。相关性分析及冗余分析结果表明,对抗氧化活性影响较为显著的因子为葡萄糖(Glc)、核糖(Rib)、木糖(Xyl)(P <0. 01)。     

Surface and submarine pollination in the seagrass Zoster a marina L

COX, P. A., LAUSHMAN, R. H. & RUCKLESHAUS, M. H., 1992. Surface and submarine pollination in the seagrass Zostera marina L. Hydrophilous plants can be divided into three ecological categories depending upon whether their pollen is transported above, on, or under the water surface. A mixed mode of submarine and surface hydrophilous pollination occurs in the seagrass Zostera marina L. In the surface mode of pollination, pollen rafts or 'search vehicles' which superficially resemble snowflakes, form at low tide and are transported on the surface of the sea by winds and water currents. Some of the search vehicles collide with the floating female stigmas, effecting pollination. In the submarine mode of pollination, small pollen masses resembling whisk brooms travel beneath the surface of the water. Although we failed to observe a submarine pollination event, SEM analysis of stigmas from subtidal populations confirms that submarine pollination does occur in Z. marina . However, observations of stigmas positioned at and below the surface of the water show surface pollination to be highly efficient. Electrophoretic evaluation of both subtidal and intertidal populations indicates significant genetic variation between populations. Given the high flux rates of surface-borne pollen and pollen viability in excess of 5 h, it is likely that surface-borne pollen is a major source of gene flow in Zostera marina populations.     

Contrasting oxygen dynamics in the freshwater isoetid Lobelia dortmanna and the marine seagrass Zostera marina

BACKGROUND: and Aims Submerged plants possess well-developed aerenchyma facilitating intra-plant gas-phase diffusion of O2 to below-ground tissues, which are usually buried in anoxic sediments. However, aquatic habitats differ in terms of O2 fluctuations in the water column and in O2 consumption of the sediment, and aquatic plants differ in aerenchymal volume and resistance to O2 diffusion through the plant and across leaf and root surfaces. The hypothesis that the freshwater isoetid Lobelia dortmanna and the marine seagrass Zostera marina should display pronounced contrasts in intra-plant O2 dynamics because of differences in morphology/anatomy, physiology and growth habitat was tested. METHODS: In order to determine the O2 dynamics and relate this to the anatomy and morphology of the two species, O2 microelectrodes were inserted in the aerenchyma of leaves and roots, the sediment pore-water, and the water column in the field. Manipulation of water column O2 in the laboratory was also carried out. KEY RESULTS: It was found that intra-plant transport of O2 between leaf and root tips takes place more readily in L. dortmanna than in Z. marina due to shorter distances and greater cross-sections of the aerenchyma. The major exchange of O2 across roots of L. dortmanna can be accounted for by small intra-plant resistances to diffusion, larger root than leaf surfaces, and greater radial diffusive resistance of leaves than roots. In contrast, the major O2 exchange across leaves than roots of Z. marina can be accounted for by the opposite anatomical-morphological features. The larger aerenchymal volume and the smaller metabolic rates of L. dortmanna compared to Z. marina imply that turnover of O2 is slower in the aerenchyma of L. dortmanna and O2 fluctuations are more dampened following changes in irradiance. Also, O2 accumulated in the aerenchyma can theoretically support dark respiration for a few hours in L. dortmanna but for only a few minutes in Z. marina. CONCLUSIONS: The build-up of O2 in the pore-water of L. dortmanna sediments during the day as a result of high release of photosynthetic O2 from roots and low O2 consumption of sediments means that sediment, aerenchyma and water are important O2 sources for respiration during the following night, while Z. marina relies on the water column as the sole source of O2 because its sediments are anoxic. These differences between L. dortmanna and Z. marina appear to represent a general difference between the isoetid species mainly inhabiting sediments of low reducing capacity of oligotrophic lakes and the elodeid freshwater species and marine seagrasses mainly inhabiting sediments of higher reducing capacity in more nutrient-rich habitats.     

Atrazine Tolerance of Grass Species with Potential for Use in Vegetated Filters in Australia

The response of introduced (Pennisetum clandestinum Hochst.) and native (Stipa aristiglumis F. Muell., Themeda australis (R. Br.) Stapf, Danthonia spp. (L.) grasses to the herbicide atrazine was studied in plants with the potential for use in vegetated filters (biofilters) designed to reduce chemical loads in agricultural runoff. The response was detected by photosynthetic inhibition using leaf chlorophyll fluorescence. With continuous short-term (14 days) dosing with atrazine in sand culture, P. clandestinum showed the greatest tolerance, regardless of the dose (20–500 μg/L). In a clay vertosol soil in the glasshouse, the four species were tolerant to longer-term (84 days) application of three successive doses of simulated run-on, each dose containing 100 μg/L atrazine, a concentration which is comparable to the highest reported in runoff from agricultural land in Australia. Even with a subsequent single atrazine dose at ∼ ∼5000 μg/L, established plants of the four species showed signs of quick recovery (7–21 days) to normal photosynthetic activity. In a field experiment with simulated run-on, applied to P. clandestinum pasture in sandy loam soil, repeated doses at concentrations up to 1000 μg/L gave no significant response; only a subsequent single dose of 5000 μg/L had significant effects, from which plants soon recovered. Although damage from atrazine can be demonstrated with continuous dosing in non-adsorbing media, in soil culture the tolerance of the four selected species to repeat doses of atrazine shows they may be used confidently for biofiltering purposes. P. clandestinum was especially tolerant.     

Atrazine movement in soil: Comparison of field observations and PRZM simulations

The predictive capability of the pesticide root zone model (PRZM) was investigated for herbicide atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] in corn production under no‐till (NT) and conventional‐till (CT) management practices. Simulation values of atrazine residues obtained using our site‐specific soil and environmental data were compared with the actual values measured in soil samples taken from the root zones of the NT and CT plots during three growing seasons: 1986, 1987, and 1988. The mean concentration of atrazine in soil at each sampling time and depth after application, for each tillage treatment plot (NT or CT), was estimated based on the type of distribution (i.e., normal or lognormal). Overall, the PRZMs simulated concentrations for the top 10 cm of soil compared well with the atrazine residues measured in the CT plots, but overestimated measurements in NT plots. For example, in 1986 the mean atrazine concentration measured in soil samples taken 6 d after application from the top 10 cm of CT plots was 548 μg/kg (S.E. 198 μg/kg), and the PRZM predicted value was 690 μg/kg. In contrast, the mean atrazine concentration for the same soil depth increment in NT plots was 385 μg/kg (S.E. 154 μg/kg), with a PRZM predicted value of 674 μg/kg. Although the PRZM prediction was closer to the measured mean for atrazine concentrations in the top 10 cm of the CT system, the model did not transport atrazine to the lower soil depths, as the actual values have indicated in all 3 years. The results of this model comparison, especially for the lower soil depths (20 to 30 cm) in the NT practice, indicated that the PRZM model does not account for the preferential transport of, and, consequently, underestimates the atrazine residue levels in the lower soil profile under NT management systems.     

Effects of pesticides on seagrass beds

In the German Wadden Sea there has been a remarkable decline in seagrass beds. It was the aim of this study to test whether herbicide contamination could be a reason for this. Concentrations of triazine herbicides such as atrazine, simazine and terbutylazine as well as phenylurea herbicides were measured in Wadden Sea sediments within or in the neighbourhood of seagrass meadows. Sediments were thus used as a marker for medium-term contamination of the Wadden Sea. The respective concentrations were examined in relation to the density and status of the seagrass meadows. Preliminary results show that there may be a connection between seagrass decline and herbicide contamination in the parts of the Wadden Sea sampled. A comparison with other contamination is also given. Received: 11 January 1999 / Received in revised form: 1 December 1999 / Accepted: 8 December 1999     

The effects of seagrass (Zostera japonica) canopy structure on associated fauna: a study using artificial seagrass units and sampling of natural beds

The importance of seagrass canopy to associated fauna was assessed by comparing the species richness, abundance and diversity of the epi- and infaunal macroinvertebrate assemblages in a seagrass (Zostera japonica Ascherson and Graebner) bed and the adjacent unvegetated area in Hong Kong. Seagrass cover had significant effects on the composition and abundance of the associated fauna and the amount of detritus accumulated on the sediment surface. Detritus abundance was significantly higher in the seagrass bed, and was positively correlated with both the above- and belowground biomass of Z. japonica. Both the abundance and species richness of the epi- and infauna were significantly positively correlated with the belowground biomass of the seagrass and detritus standing crop. Macrofaunal species richness was higher (118) in the seagrass bed than the adjacent unvegetated areas (70), with a higher degree of similarity between the infauna than the epifauna of the two habitats. While all species recorded from the unvegetated areas were found in the seagrass bed, 48 species occurred only in the seagrass-covered areas. Species richness of epifauna was significantly higher in the seagrass bed, but there was no difference between infaunal species of the two habitats. On the contrary, faunal (epi- and infauna) abundance was significantly higher in seagrass areas. The seagrass bed also supported species of small tellinid bivalves previously not recorded from Hong Kong. Artificial seagrass units (ASUs, 0.2 m(2)) with four combinations of leaf density and leaf length and a control (bare sand) were placed at short distances from natural patches of Z. japonica. The composition, abundance and biomass of the epibenthos associated with the ASUs and the control were recorded after 3 months in the field. While species richness did not differ among the treatments, total abundance of epibenthos was significantly higher in the high density-long leaves (HL) treatment than in the control. Results of a discriminant analysis using log-transformed abundance data suggest that the gastropod Clithon oualaniensis, the mussel Musculista senhousia and the crab Thalamita sp. were important species distinguishing the assemblages in the various treatments. All the three species were significantly more abundant in the HL treatment than in the low density-short leaves (LS) treatment and the control. By contrast, there was no significant difference in the biomass of the epifauna, but discriminant analysis again separated the five treatments based on the composition of the biomass, with the same three species identified as the most important discriminating species. The species richness and abundance of the epifauna associated with the ASUs were similar to the adjacent unvegetated areas, but significantly lower than in the Zostera patches. The physical canopy structure of Z. japonica beds increased the abundance of the epibenthos, potentially through provision of canopy and indirectly through trapping of detritus.     

Optimization of saccharification and ethanol production by simultaneous saccharification and fermentation (SSF) from seaweed, Saccharina japonica

Ethanol was produced using the simultaneous saccharification and fermentation (SSF) method with macroalgae polysaccharide from the seaweed Saccharina japonica (Sea tangle, Dasima) as biomass. The seaweed was dried by hot air, ground with a hammer mill and filtered with a 200-mesh sieve prior to pretreatment. Saccharification was carried out by thermal acid hydrolysis with H(2)SO(4) and the industrial enzyme, Termamyl 120 L. To increase the yield of saccharification, isolated marine bacteria were used; the optimal saccharification conditions were 10% (w/v) seaweed slurry, 40 mM H(2)SO(4) and 1 g dcw/L isolated Bacillus sp. JS-1. Using this saccharification procedure, the reducing sugar concentration and viscosity were 45.6 ± 5.0 g/L and 24.9 cp, respectively, and the total yield of the saccharification with optimal conditions and S. japonica was 69.1%. Simultaneous saccharification and fermentation was carried out for ethanol production. The highest ethanol concentration, 7.7 g/L (9.8 ml/L) with a theoretical yield of 33.3%, was obtained by SSF with 0.39 g dcw/L Bacillus sp. JS-1 and 0.45 g dcw/L of the yeast, Pichia angophorae KCTC 17574.     

阿特拉津和林丹对紫贻贝生长与繁殖净能的影响

本研究评估了亚致死浓度的林丹(1/2的60dLC50,0.935mg/L)和阿特拉津(1/2的60dLC50,3.585mg/L)对海洋性贝类影响的生理学反应。林丹和阿特拉津是已被公认的环境污染物质。56d的实验表明,这两种农药在贝类体内具有积累作用,而且在体内各器官的积累程度与其作用的靶器官相一致。林丹在体内的积累浓度(每克干重372μg)比阿特拉津(每克干重137μg)更高。该贝类在林丹中暴露56d,其氧的消耗比对照组降低10%,而在阿特拉津中则比对照组提高了29%。经林丹和阿特拉津暴露后,增加了氨排泄物。但是,两种农药均使贝类的取食率和吸收率下降。林丹会降低贝类的取食率、氧消耗、氨排泄、食物吸收率以及生长范围。在形式上,阿特拉津对贝类的影响与林丹的影响有不同之处,它会降低贝类的取食率和食物吸收率,但与林丹不同的是,它会提高贝类的氧消耗和氨排泄。总之,阿特拉津会明显地减小贝类繁殖净能。因此,阿特拉津暴露与林丹暴露的毒性症状是一致的。结合组织化学分析,贝类的生理学反应可作为一种理想的环境监测工具。研究结果表明,在二分之一的半致死浓度下暴露两个月,不仅能有效地证明林丹和阿特拉津在贝类组织内具有积累作用,而且对这些积累能产生生理反应。