硝态氮与无机磷浓度及其比例对簇生舟形藻生长生理及细胞形态的影响

为探究水体中不同氮、磷营养盐水平对硅藻生长的影响以及硅藻对营养盐污染的指示作用,该研究以簇生舟形藻(Navicula gregaria Donkin)为研究对象,采用不同浓度硝态氮(NO~-_3-N,0.5～500 mg·L~(-1))、无机磷(H_2PO~-_4-P,0.05～25 mg·L~(-1))及氮磷浓度比(5∶1～100∶1)于室内培养13 d,胁迫期间测定分析各处理组簇生舟形藻的生长状况、生理指标及细胞畸形率。结果显示:(1)当NO~-_3-N、H_2PO~-_4-P浓度及氮磷比分别低于50 mg·L~(-1)、1 mg·L~(-1)和50∶1时,簇生舟形藻13 d内的细胞密度、叶绿素a含量和蛋白质含量均随着浓度的增加逐渐升高,藻细胞内的MDA含量及SOD、CAT活性呈现持续下降的趋势;当NO~-_3-N浓度为50 mg·L~(-1)、H_2PO~-_4-P浓度为1 mg·L~(-1)、氮磷比为50∶1时,簇生舟形藻的细胞密度、叶绿素a含量、蛋白质含量以及比生长速率最高;高浓度NO~-_3-N( 250 mg·L~(-1))、H_2PO~-_4-P( 5 mg·L~(-1))和高氮磷比( 50∶1)处理下,簇生舟形藻细胞密度、叶绿素a含量、蛋白质含量多显著降低,MDA含量及SOD、CAT活性与其他处理组相比却呈现明显上升趋势。(2)在500 mg·L~(-1)NO~-_3-N和25 mg·L~(-1)H_2PO~-_4-P处理第13天时,分别有8.6%和7.2%藻细胞形态发生畸变,表面不规则,细胞严重变形,细胞中心区域增宽,细胞末端微尖等现象。研究表明,水体中增加适当浓度和比例的氮磷营养盐可以促进簇生舟形藻类的生长和生理活性,但当环境中氮、磷及氮磷比过高时则会抑制簇生舟形藻的主要生理指标,最终影响其在水体中的生长情况甚至导致其生态群落结构发生变化。     

富营养水体中总氮与总磷比对苦草生长的影响

在室外受控实验条件下,研究了富营养水体中不同氮磷比(TN/TP)(12.5∶1、25∶1、50∶1)对苦草(Vallisneria spiralis)生长的影响.结果表明:当TN/TP为25∶1时,苦草的生长状态最好,苦草生物量的增长率最大,分别高于TN/TP为12.5∶1和50∶1时的54%和31%;当TN/TP为25∶1时,附着生物尤其是附着藻类的生长状态最差,对苦草生长的不利影响最小;可见,富营养水体中适宜于苦草生长的TN/TP为25∶1;TN/TP为25∶1这一比例的应用具有相对性,当水体营养浓度低于限制水平时,该比例适用,如果水体中营养盐浓度超过限制水平时,该比例则不适用.     

太湖水体叶绿素a含量与氮磷浓度的关系

基于太湖水体1993—2002年5—9月监测资料,进行了叶绿素a含量与总氮(TN)、总磷(TP)浓度关系的分区统计分析,探讨了太湖藻类生长的TN、TP适宜浓度。结果表明:太湖叶绿素a含量与TN、TP浓度的关系存在显著的空间差异;在梅梁湾和西北区,当TN、TP浓度较低时,叶绿素a含量与TN、TP浓度呈正相关;当TN、TP浓度较高时(梅梁湾TN、TP浓度分别超过5.4和0.31mg.L-1;西北区分别超过4.5和0.27mg.L-1),叶绿素a含量与TN、TP浓度呈负相关;在湖心区和贡湖区,叶绿素a含量与TN、TP浓度呈正相关,尤其当TP浓度超过0.1mg.L-1时,叶绿素a含量随TP浓度增加而上升;在东太湖和湖东滨岸区,随TN、TP浓度的升高,叶绿素a含量变化较小;在西南区,叶绿素a含量与TN浓度无显著相关关系,与TP浓度呈正相关;太湖藻类生长的适宜浓度是TN<5.4mg.L-1,TP为0.1～0.31mg.L-1。     

伊乐藻对富营养化水体的净化作用分析

利用室内静态模拟生长体系,研究了沉水植物伊乐藻在夏季高温季节5种不同氮磷营养条件水体中的生长状况及其对水体中氮、磷的净化效果。结果表明:低氮(1.0～5.5mg.L-1)、低磷(0.3～1.3mg.L-1)营养盐水体中的伊乐藻生长状态良好,但在高浓度氮(8.0mg.L-1)、磷(2.0mg.L-1)营养盐条件下,伊乐藻生长在后期受到部分抑制。伊乐藻对水体氮磷的去除效果随水体氮磷浓度的增加而增强,与起始水体氮磷含量相比,不同营养盐条件处理50d时,各处理伊乐藻对水体总氮的去除率分别达到55.88%、85.51%、88.18%、93.57%、95.97%,总磷的去除率分别达到47.55%、74.31%、57.75%、79.23%、74.92%。可见,伊乐藻在夏季高温季节对水体氮磷有一定去除效果,且对氮的去除效率高于磷,其对高氮、高磷环境有一定的耐受能力。     

背角无齿蚌对水体净化作用的研究

通过设置不同生物量的背角无齿蚌, 研究其对再悬浮水体总悬浮质(TSS)、叶绿素a(Chla)及水体营养盐含量的影响。结果表明: (1)背角无齿蚌可以快速降低水体中总悬浮质(TSS)和叶绿素a(Chla)的浓度; (2)增大背角无齿蚌生物量可加快水体总悬浮质(TSS)和叶绿素a(Chla)浓度的下降速度; (3)背角无齿蚌在第2 天可降低水体总氮(TN)、总磷(TP)、总溶解磷(TDP)的含量, 升高总溶解氮(TDN)的含量, 但试验结束时, 空白组和有蚌组总氮(TN)、总溶解氮(TDN)、总磷(TP)、总溶解磷(TDP)均没有显著差异(P>0.05)。因此, 背角无齿蚌可在水体生态修复初期用于快速降低水体悬浮物和浮游藻类含量, 但从长期看, 不能明显改善水体营养盐含量。     

铵态氮和浮游植物对穗花狐尾藻的生理影响

为探讨铵态氮-浮游植物-沉水植物三者之间关系,在滇池岸边开展室外模拟实验。在初始叶绿素a为100μg·L~(-1)的浮游植物密度下,研究不同浓度(0、0.05、0.15、0.50、1.50、5.00 mg·L~(-1))铵态氮和浮游植物对穗花狐尾藻的生长和生理状况的影响。结果表明:各处理组穗花狐尾藻的各项生长和生理指标在实验期间存在明显差异;当铵态氮浓度为1.50mg·L~(-1)时,穗花狐尾藻的株高和生物量明显大于其他处理组;穗花狐尾藻叶片的总叶绿素含量、光合活性和可溶性蛋白在铵态氮浓度为1.50 mg·L~(-1)时,实验期间能维持原来的水平,其余铵态氮浓度下,呈现下降的趋势;在铵态氮与浮游植物的复合作用下,适宜穗花狐尾藻生长的铵态氮浓度为1.50 mg·L~(-1),高浓度的铵态氮(5.00 mg·L~(-1))和氮缺乏(NH4+-N≤0.50 mg·L~(-1))都不利于穗花狐尾藻的生长;铵态氮浓度达到5.00 mg·L~(-1)时,浮游植物大量生长带来的相关效应,如水体浊度上升,水下光强降低等,导致穗花狐尾藻耐受铵态氮的阈值较单一铵态氮胁迫下的耐受阈值低,此时,沉水植物对藻类的抑制效应也将解除,水华大量发生,叶绿素a的浓度可达(948.1±313.0)μg·L~(-1)。     

巢湖叶绿素a浓度的时空分布及其与氮、磷浓度关系

基于巢湖水体2002~2007年水质监测资料,对叶绿素a浓度的分布、动态及与TN、TP的关系进行了统计分析。巢湖叶绿素a浓度与TN、TP的浓度分布存在明显的空间差异,西半湖叶绿素a浓度全年高于20μg/L,TN为1.94~3.84mg/L,TP为0.20~0.42mg/L;东半湖叶绿素a浓度全年小于5.5μg/L,TN为0.95~1.83mg/L,TP为0.08~0.14mg/L。在东半湖,叶绿素a含量与TN呈不明显的正线性关系,当TP浓度较低时,叶绿素a随TP的增加小幅上升,但是当TP>0.15mg/L时,叶绿素a随TP的增加而明显上升;在西半湖,当水体TN<5.8mg/L或者TP<2.0mg/L时,叶绿素a含量与TN、TP关系为正线性关系,当TN在5.8~9.4mg/L或者TP介于0.2~0.3mg/L间时,叶绿素a含量与TN、TP关系为不显著的负线性关系,当TP浓度>0.3mg/L时,叶绿素a含量与TP关系又为正线性关系。西半湖叶绿素a浓度的变化可能是藻类生物活动与沉积物及水体中营养盐的相互作用结果。在治理巢湖富营养化时,应优先控制西半湖的磷元素。     

不同水体营养条件对刺苦草和密刺苦草生长的影响

以贡湖水体营养盐水平现状[ρ(TN)0.4~4 mg·L-1、ρ(TP)0.04~0.4 mg·L-1]为依据,研究不同梯度营养盐水体对刺苦草(Vallisneria spinulosa)与密刺苦草(V.denseserrulata)生长及生理的影响,探讨同属沉水植物对不同营养水体的响应差异。结果表明:水体营养条件对两种沉水植物的生物量累积没有显著影响;处理组刺苦草的最大株高分别增加了19%(P0.05)、63%(P0.05)、205%(P0.01),密刺苦草高浓度中植株最大株高与低浓度差异显著(P0.05);刺苦草与密刺苦草在高浓度水体中的克隆繁殖能力分别下降了30%和20%;低浓度水体中刺苦草与密刺苦草叶片丙二醛含量增加(P0.05),叶绿素含量减少(P0.05),表明其受到养分胁迫;在ρ(TN)1.5~4 mg·L-1、ρ(TP)0.15~0.4 mg·L-1范围内,两种苦草表现出较强适应性。     

珠江口及毗邻海域营养盐对浮游植物生长的影响

基于2006年7月(夏季),10月(秋季)和2007年3月(春季)的现场调查数据,对珠江口及毗邻海域中的营养盐和叶绿素a等环境生态因子的时空分布特性进行了对比分析,研究了氮磷比与叶绿素a含量和种群多样性之间的联系,探讨了该海域营养盐对于浮游植物生长的影响。结果表明:(1)研究海域营养盐表现出较强的季节和空间差异性,总氮(TN)和总磷(TP)浓度均值春季(1.545 mg/L、0.056 mg/L)和夏季(1.570 mg/L、0.058 mg/L)均大于秋季(1.442 mg/L、0.034 mg/L),且春夏季浓度空间差异更明显。(2)调查期间海域营养盐含量超标现象突出,夏季尤为明显。无机氮(DIN)总体均值0.99 mg/L,超四类海水标准限值1倍,活性磷酸盐(PO4-P)总体均值0.021 mg/L,DIN∶PO4-P平均值为130;叶绿素a浓度与营养盐、p H、温度有较显著的相关性。(3)叶绿素a浓度较高的站位,具有较高的DIN∶PO4-P值,但浮游植物多样性指数偏低,优势种明显,主要为中肋骨条藻。氮磷比的改变会影响不同生长特性的浮游植物间的竞争和种群结构的改变;今后海洋污染治理中,在控制氮、磷污染时要注意氮磷比的改变可能造成的浮游生态影响。     

密云水库水体营养状态分析

调研结果显示 ,密云水库的营养特征为浮游藻类响应型。浮游藻类的群落结构是绿藻 (Chlorophyta)—硅藻(Bacillariophyta)型。库区水体TN 0 86mg/L ,TP 0 .0 2 2mg/L ,浮游藻类的细胞密度 4 0 5 2 3× 10 4/L。 4项指标 (Tr、TP、CODmn、chla)的TSIM 值 4 0 1— 4 9 6 ,水体为中营养。但TN、TP和浮游藻类细胞密度增长较快 ,水体向富营养发展的趋势明显。主要制约因素是面源、点源和内源对水体的污染。北京市水资源紧缺 ,密云水库是主要饮用水源地。保护流域生态环境 ,治理污染 ,涵养水源 ,实现水资源的可持续利用已很迫切     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.