营养盐因子对细基江蓠繁枝变种氮、磷吸收速率的影响

在实验室条件下,研究了营养盐因子对细基江蓠繁枝变种的氮、磷吸收速率的影响。分别进行了营养盐浓度与温度双因子试验,氮磷比与荧 浓度双因子试验肽不同化合态氮比例单因子试验。（1）氮、磷的吸收速率随营养盐浓度的升高而增大,氮的吸收速率在21℃,总氮浓度为100μmol/L时最大,达2.58μmol/(g.h);磷的吸收速率在31℃,总磷为6．3μmol/L时最大,达0.17μmol/(g.h),温度与营养盐浓度有显著的交互作用效应。（2）当氮浓度一定时,环境氮磷比对氮的吸收率无显著影响,但对磷的吸收速率有显著影响,藻中收的氮磷比随环境氮磷比的不同而变化,（3）对3种不同化合态氮的吸收速率与培养液中各种氮占总无机氮的比例呈正相关,当三比例相同时,对NH4^ -N、NO3^--N格NO2^-析吸收分别占总吸收氮的40．7％、28．5％和30．8％。     

台湾海峡上升流区浮游植物对营养盐添加的响应

2006年6月在台湾海峡近岸上升流区通过表层水体营养盐添加的现场培养实验,研究该海区营养盐限制情况及其浮游植物水华产生的主要影响因素.对营养盐,叶绿素a浓度和浮游植物细胞丰度进行了测定,结果表明,实验中不存在明显的硅限制;氮磷营养盐均存在明显的限制,且氮限制情况更为严重.营养盐添加后,冰河拟星杆藻(Asterionellopsis glacialis)等硅藻迅速生长成为优势藻种,其对氮磷的利用机制有所不同.对氮营养盐采取吸收后迅速同化利用,相较于硝酸盐的补充,氨氮补充条件下优势硅藻更易迅速生长并迅速死亡;对磷营养盐的利用则由于体内磷库的存在,采用迅速吸收后贮存在体内慢慢消耗的利用机制.氮营养盐的补充是上升流期间浮游植物水华产生的主要因素.     

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。     

镇海水库拟柱孢藻的分离鉴定和氮磷对其生长的影响

以分离自广东省镇海水库的拟柱孢藻N8为对象, 探究其在不同磷浓度及氮磷浓度组合下的生长情况。结果表明, 拟柱孢藻N8对磷的适应范围很宽, 在0.025.12 mg/L磷浓度下均能生长, 最适生长磷浓度范围为0.165.12 mg/L, 磷浓度的升高能显著延长拟柱孢藻的对数生长期和提高生物量。动力学分析表明, 拟柱孢藻N8有较低的KSP值, 对磷元素的亲和性较高, 在磷营养贫乏的环境下更容易形成优势。在氮磷组合实验中, 低氮(0.5 mg/L)显著抑制拟柱孢藻的生长, 且这种生长抑制不受磷浓度的影响; 而在低磷(0.04 mg/L)条件下, 水体中氮浓度的增加会显著促进拟柱孢藻的生长, 拟柱孢藻在高氮中磷和高氮高磷下的生长显著优于其他氮磷组合条件。研究表明, 广东省水库拟柱孢藻的生长受磷的限制较弱, 氮是其生长的决定因子。       

氮浓度对铜绿微囊藻、大型溞和金鱼藻三者相互作用的影响

为了解氮浓度对生物操纵和草-藻竞争的影响, 选取铜绿微囊藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和沉水植物的代表, 在温度25℃, 光强2600 lx, 光暗比14h﹕10h, 磷浓度1.5 mg/L时, 研究5种氮浓度(0.5、2、4、8和16 mg/L, 用KNO₃溶液配制)下, 溞-藻, 草-藻和溞-草-藻共培养时各自的增长率和培养液中氮磷削减率的变化。结果表明: 在单独培养铜绿微囊藻时, 氮浓度控制在1.97 mg/L以下, 可有效降低培养液中藻的增长率。在溞-藻共培养时, 大型溞有效控藻的氮浓度范围为0.5—4 mg/L; 在草-藻共培养时, 有效控藻的氮浓度范围为0.5—2 mg/L, 对应氮浓度下(0.5和2 mg/L), 实验末期铜绿微囊藻细胞密度分别是溞-藻共培养的23.89%和21.51%, 控藻效果更好; 在溞-草-藻三者共培养时, 有效控藻的氮浓度范围为0.5—16 mg/L, 且氮浓度为0.5—4 mg/L时, 大型溞和金鱼藻的增长率均显著大于铜绿微囊藻, 铜绿微囊藻的增长率均为负值, 控藻效果最好。大型沉水植物的加入, 可以有效提高生物操纵的控藻效果, 减少水中氮磷含量, 长期有效地改善水质。     

雨生红球藻在红光下的生长及营养盐消耗特征

研究了在红光下雨生红球藻Haematcoccus pluvialis的细胞增殖过程中, 叶绿素荧光参数的变化以及氮磷消耗特征, 并且研究了在不同初始氮磷浓度下, 细胞增殖周期、色素变化以及氮磷消耗速率, 以期为雨生红球藻的培养工艺提供参考。结果显示: (1)在细胞增殖过程中, 光合荧光参数PSⅡ、qP、ETR与细胞增殖周期一致, 没有显著差异。Fv/Fm、NPQ则随着细胞密度的上升而下降, 随着细胞密度下降而上升, 且发生变化的拐点与营养盐胁迫造成细胞数量下降的时间点基本一致。(2)以不同初始氮磷浓度(氮磷比10:1, 重量比)的培养液接种细胞, 较高浓度的氮磷条件(45/4.5130/13.0 mg/L), 比较低浓度的氮磷条件(15/1.5 20/2.0 mg/L)有利于提高批次培养后的细胞终产量。但是, 在初始高浓度氮磷下, 接种初期细胞受到胁迫, 相对增长速率小; 氮磷消耗率低, 后期浓度维持高位; 藻细胞指数生长延迟, 培养周期变长。在红光下, 最优化的氮磷接种浓度为45/4.5 mg/L。研究结果对半连续培养雨生红球藻的应用进行了讨论。       

温度和氮磷浓度对平裂藻和栅藻生长及竞争的影响

为了解温度及氮磷浓度对平裂藻和栅藻生长及竞争的影响,分别在18、25和35℃条件下,以BG11培养基为基础,设置了不同的氮磷浓度组,进行了2种藻的单独培养试验和混合培养试验,结果表明:在纯培养条件下,低营养浓度组(磷浓度分别为0.1和0.5 mg/L)平裂藻在3种温度下基本停止生长,高营养盐浓度组(磷浓度分别为1.0和1.5 mg/L)除18℃1.0 mg/L组停止生长外,其余均能正常生长增殖,且细胞最大密度表现为25℃ 18℃ 35℃, 1.5和1.0 mg/L浓度组细胞生长差异不显著。栅藻在纯培养条件下,细胞密度总体表现为随着营养盐浓度升高而增加的趋势,细胞最大密度表现为18℃ 25℃ 35℃。在混合培养试验中,除35℃、1.5 mg/L组平裂藻对栅藻的竞争抑制参数大于栅藻对平裂藻的竞争抑制参数外,其余试验组均表现为栅藻受平裂藻影响较小。在混合培养体系中, 0.1 mg/L组平裂藻仍基本停止生长, 0.5 mg/L组受栅藻的刺激作用,生长优于纯培养体系。1.0和1.5 mg/L组均受栅藻的抑制作用,且浓度越高抑制作用越强。       

引黄水库藻类变化特征及其影响因素研究

以济南鹊山引黄水库为研究对象,系统研究了2008-2012 年间其水中浮游藻类的种类和数量变化特征以及藻类细胞密度与总氮、总磷浓度的相关性,并在实验室模拟条件下分析了温度、光照、氮磷营养盐等条件对其藻类生长影响。结果表明,该水库水藻密度年际、年内变化较大,年平均值均在500 万个/L 以上,藻种共7 个门,37 个属,蓝藻和硅藻为水库的优势藻种。该水库藻类生长的最佳温度为25℃,光强为3 000 lx,氮磷营养盐对藻类生长影响排序为硝酸盐>磷酸盐>亚硝酸盐>氨氮。磷可能是藻生长的限制性因子,在夏、秋季及水库磷浓度大幅变化时易发生水华。     

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。       

氮磷浓度对藻-溞-草间相互作用的影响

为了解氮磷浓度对生物操纵效果的影响, 以小球藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和大型沉水植物的代表, 建立了它们之间相互作用的水生微宇宙模型。研究了在25℃、2000—3000 lx 的温度和光照下, 不同氮磷浓度对三者生长的影响。结果表明: 两者共培养时, 在高氮(10.5 mg/L)条件下, 磷浓度小于0.1 mg/L 对大型溞繁殖和金鱼藻的生长有利; 磷浓度介于0.1—2 mg/L 时小球藻呈大暴发趋势, 而金鱼藻的生长则明显受抑制。在低氮(0.5 mg/L)条件下, 磷浓度不大于0.5 mg/L, 大型溞对小球藻有较好的抑制作用, 金鱼藻与小球藻无显著互抑现象; 磷浓度增大为2 mg/L 时, 小球藻对金鱼藻生长产生明显抑制。在0.05—2 mg/L 的磷浓度范围及高氮和低氮条件下三者共培养时, 大型溞数量及金鱼藻生物量均不同程度的升高,且小球藻数量得到了有效抑制, 以磷浓度为0.1—0.5 mg/L 时效果最佳; N/P 比值对藻、溞、草间的相互作用有重要影响, 在藻-溞系统中, 大型沉水植物的加入可以大大提高控藻效果, 减小N/P 比值波动带来的不利影响。与低氮情况相比, 高氮条件对金鱼藻、大型溞及小球藻的增长均存在一定抑制作用。磷浓度为0.5 mg/L时的水体氮磷去除效果好于其他磷浓度梯度。       

Studies on Fat Accumulation in Nitzschia palea Kutz

Fat accumulation in Nitzschia palea Kütz. starts perceptiblyat the end of the exponential phase of growth and reaches amaximum during the stationary phase of growth when the wholecell is filled with fat. Filtrates from old cultures enhancedfat synthesis probably by the production of an autotoxin whichinhibits cell growth but at the same time favours fat synthesis.The presence of an inhibitory autotoxin has not been provedbut indirect evidence suggests its presence. The nitrogen content of the culture medium also influences theamount of fat formed, more fat being accumulated in nitrogen-deficientmedia than in media provided with adequate nitrate supply. Theoptimum temperature for the growth of N. palea was found tobe about 30 °C while that for fat synthesis was around 35°C. Below 15 °C and above 40 °C, fat synthesis wasdrastically reduced. Blue and red light independently favoured fat synthesis whereasa combination of both did not. This is probably due to the selectiveinfluence of these wavelengths on the production of fat precursorsor intermediates.     

Overwintering of Microcystis aeruginosa Kutz. in a shallow lake

The standing crop and photosynthetic activity of Microcystisaeruginosa Kütz. in both the plankton and sediment wereinvestigated from November 1979 to May 1982 in Lake Kasumigaura,Japan. The number of planktonic colonies of this species decreasedfrom early autumn to early spring, but increased in the sedimentduring late summer and autumn. The overwintering colonies inthe sediment were –100–1000 times greater per unitarea than those in lake water. No photoinhibition of photosynthesiscould be observed in overwintering Microcystis. The values ofthe initial slopes of photosynthesis-light (P-I) curves weresimilar to those of the summer population, although the maximumphotosynthetic rate (P_max) measured at 20°C was lower thanthat of the summer planktonic population. In winter the valuesof initial slope of the P-I curve, and the ratio of phycobilinto chlorophyll a sorted from sediment were higher than in coloniesfrom the plankton.     

Interconversion of trans, trans and cis, trans farnesol by enzymes from Andrographis

When trans, trans-farnesol [4,8,12-¹⁴C₃,1-³H₂] is isomerized to cis, trans-farnesol by soluble enzymes from Andrographis paniculata tissue cultures, 50% of the tritium label is lost. The same loss is observed when isomerization occurs in the opposite direction. This is in accordance with the proposed mechanism for isomerization via aldehydes.     

Dinuclear ruthenium sawhorse-type complexes containing bridging ligands with ferrocenyl substituents in endo/endo, endo/exo and exo/exo orientations

The dinuclear ruthenium complexes Ru₂(CO)₄(OOCC₅H₄FeC₅H₅)₂L₂ (L = NC₅H₅: 1, L = PPh₃: 2) have been synthesized from Ru₃(CO)₁₂, ferrocene carboxylic acid and pyridine or triphenylphosphine, respectively. The single-crystal X-ray structure analysis reveals for 1 and 2 a Ru₂(CO)₄ sawhorse backbone with the two ferrocenyl substituents of the two carboxylato bridges being endo/exo with respect to each other in the solid state. With the new pyridine derivative NC₅H₄OOCC₅H₄FeC₅H₅ (4-ferrocenoyl pyridine) (3) as axial ligand, the complex Ru₂(CO)₄(OOCC₅H₄FeC₅H₅)₂(NC₅H₄OOCC₅H₄FeC₅H₅)₂ (4) was obtained, the single crystal X-ray structure analysis showing an exo/exo orientation of the two carboxylato bridges in the solid state. The endo/endo orientation is found in the solid-state structure of Ru₂(CO)₄(HNOCC₅H₄FeC₅H₅)₂(PPh₃)₂ (5), the two OCNH bridges being transoïd with respect to each other; this complex is accessible from Ru₃(CO)₁₂, ferrocenamide and triphenylphosphine.     

Nitrogen-containing non-steroidal secondary metabolites of Solanum, Cyphomandra, Lycianthes and Margaranthus

Of the 49 species of Solanum studied, cuscohygrine has been detected in 25, solamine and related amines in 17 and solamine-derived amides in 16. Five species of Cyphomandra examined all contained both amines and amides. From roots of Margaranthus solanaceus cuscohygrine has been isolated which probably occurs, too, in roots of Lycianthes rantonnettii. The distribution of these compounds throughout the taxa could be of chemotaxonomic value.     

Cortinarius sect. Brunnei (Basidiomycota, Agaricales) in North Europe

The section Brunnei was extensively studied based on material from North Europe. To stabilise the nomenclature we studied the relevant types of taxa included in this section. Phylogenetic relationships and species limits were investigated using rDNA ITS sequences and the results were compared with the morphological data. We recognised 11 species: Cortinarius brunneus, C. clarobrunneus comb. nov., C. coleoptera, C. ectypus, C. gentilis, C. glandicolor (neotypified), C. pseudorubricosus, and four species described as new C. caesiobrunneus, C. albogaudis, C. carabus, and C. cicindela. They are described here and their taxonomy, ecology, distribution, and relationships are discussed. In addition, a key to species of the section Brunnei is provided. A total of 77 new sequences of 11 species are published including nine type sequences. Also the taxonomic assignments of sequences in the public databases belonging to the section Brunnei are revised.     

Iridoid glucosides in Griselinia, Aralidium and Toricellia

From three of five investigated species of Griselinia a new iridoid glucoside, griselinoside, was isolated. It was found to be present also in foliage of Aralidium pinnatifidum and Toricellia angulata, accompanied in the former by aralidioside another novel iridoid glucoside. The structures and absolute configurations of the two iridoids were elucidated by NMR spectroscopy and chemical conversions. From G. littoralis and T. angulata the glucosides magnolioside and syringoside respectively were isolated. ¹³C NMR spectra are given for thirteen iridoid derivatives.     

Recent advances in the cryopreservation of shoot-derived germplasm of economically important fruit trees of Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis

This paper presents the advances made over the last decade in cryopreservation of economically important vegetatively propagated fruit trees. Cryopreservation protocols have been established using both dormant buds sampled on field-grown plants and shoot tips sampled on in vitro plantlets. In the case of dormant buds, scions are partially dehydrated by storage at − 5 °C, and then cooled slowly to − 30 °C using low cooling rates (c.a. 1 °C/h) before immersion in liquid nitrogen. After slow rewarming and rehydration of samples, regrowth takes place either through grafting of buds on rootstocks or excision of apices and inoculation in vitro. In the case of shoot tips of in vitro plantlets, the cryopreservation techniques employed are the following: controlled rate cooling procedures involving slow prefreezing followed by immersion in liquid nitrogen or vitrification-based procedures including encapsulation–dehydration, vitrification, encapsulation–vitrification and droplet-vitrification. The current status of cryopreservation for a series of fruit tree species including Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis is presented. Routine application of cryopreservation for long-term germplasm storage in genebanks is currently limited to apple and pear, for which large cryopreserved collections have been established at NCGRP, Fort Collins (USA), using dormant buds and in vitro shoot tips, respectively. However, there are a growing number of examples of pilot scale testing experiments under way for different species in various countries. Progress in the further development and application of cryopreservation techniques will be made through a better understanding of the mechanisms involved in the induction of tolerance to dehydration and cryopreservation in frozen explants.     

Rhizobium pisi sv. trifolii K3.22 harboring nod genes of the Rhizobium leguminosarum sv. trifolii cluster

The taxonomic status of the Rhizobium sp. K3.22 clover nodule isolate was studied by multilocus sequence analysis (MLSA) of 16S rRNA and six housekeeping chromosomal genes, as well as by a subsequent phylogenic analysis. The results revealed full congruence with the Rhizobium pisi DSM 30132^T core genes, thus supporting the same taxonomic position for both strains. However, the K3.22 plasmid symbiosis nod genes demonstrated high sequence similarity to Rhizobium leguminosarum sv. trifolii, whereas the R. pisi DSM 30132^Tnod genes were most similar to R. leguminosarum sv. viciae. The strains differed in the host range nodulation specificity, since strain K3.22 effectively nodulated red and white clover but not vetch, in contrast to R. pisi DSM 30132^T, which effectively nodulated vetch but was not able to nodulate clover. Both strains had the ability to form nodules on pea and bean but they differed in bean cultivar specificity. The R. pisi K3.22 and DSM 30132^T strains might provide evidence for the transfer of R. leguminosarum sv. trifolii and sv. viciae symbiotic plasmids occurring in natural soil populations.