高浓度CO2与磷浓度对葛仙米生长和光合作用的耦合效应

在不同CO₂(400和2000 ppm)和磷浓度下(0.088—0.350 mmol/L)培养葛仙米(拟球状念珠藻, Nostoc sphaeroides Kutzing), 研究CO₂和磷对葛仙米相对生长速率、色素含量、光系统Ⅱ光化学活性和光合速率等的影响。结果显示CO₂或磷浓度对葛仙米的相对生长速率、球体粒径和数量、光饱和光合速率、呼吸速率和光合效率均有显著影响, 且两者对球体粒径和数量、叶绿素a含量、呼吸速率和光合效率存在明显交互作用。高CO₂浓度培养明显提高磷对球体粒径和数量和光合效率的效应, 同时降低高磷浓度对叶绿素a合成的抑制作用, 但两者对相对生长速率、藻胆蛋白含量、光饱和光合速率、F_v/F_m和Yield的交互作用均不显著。以上研究结果表明高CO₂浓度或磷浓度增加促进葛仙米生长主要是通过提高光合速率和光合效率来实现; 两者交互作用表明高CO₂浓度可能通过提升磷的利用效率, 降低高磷浓度对叶绿素a合成的抑制, 提高光合效率, 使球体明显增大。     

不同硝酸钾浓度对蔷薇藻生长及生理特性的影响

蔷薇藻(Rhodella reticulata)是属于红藻门的一种海洋单细胞微藻,其生长过程中产生藻胆蛋白、胞外多糖等生物活性物质.研究了不同硝酸钾浓度对蔷薇藻生长代谢的影响,分析测定蔷薇藻比生长速率、胞外多糖产量、藻蓝蛋白含量、色素含量、硝酸还原酶活性和SOD活性等参数.结果表明,与无氮培养基相比,蔷薇藻在以硝酸钾为氮源,浓度为0.75 g/L的条件下生长最好,硝酸还原酶活性最大,分别得到最大的藻蓝蛋白产量(24 mg/L)和类胡萝卜素含量(1.42 mg/L);当KNO3浓度为7.5 g/L时,获得最高叶绿素a含量为1.91 mg/L;高氮源有利于产糖,当KNO3浓度为30 g/L时,得到最高胞外多糖产量为1.633 g/L;SOD活性随硝酸钾浓度增加而增大.     

生长素吲哚乙酸对铜绿微囊藻生理生化及产毒特性的影响

为了探究生长素吲哚乙酸(IAA)对产毒铜绿微囊藻(Microcystis aeruginosa)的影响, 从生长、光合色素含量、叶绿素光诱导荧光特征、脂质氧化和微囊藻毒素合成特性等方面, 研究了IAA对M. aeruginosa CHAB6301生理生化及产毒的影响。结果表明, 在低浓度IAA(0.04和0.2 mg/L)条件下, 铜绿微囊藻生长、叶绿素含量、光合系统(PSⅡ)电子传递效率及藻毒素含量均无明显变化, 藻蓝蛋白、别藻蓝蛋白和丙二醛(MDA)含量均低于对照。高浓度IAA(1和5 mg/L)能够促进细胞生长, 提高叶绿素含量, 但是抑制藻蓝蛋白和别藻蓝蛋白含量, 降低膜脂过氧化程度和细胞内藻毒素合成。综合各指标测定结果, 低浓度IAA对M. aeruginosa CHAB6301生长和光合作用影响不明显, 而高浓度IAA可促进藻细胞生长和光合作用, 增加微囊藻水华形成几率。     

基于叶绿素荧光探讨链霉素对念珠藻生长及光合毒性效应

为了探究不同浓度链霉素对念珠藻生长和光合的毒性效应, 研究对不同浓度(0、0.05、0.1、0.2、0.5和1.0 mg/L)链霉素处理下念珠藻的生长、叶绿素荧光进行了测定。结果发现, 培养至96h, 链霉素对念珠藻的EC₅₀(96h-EC₅₀)为(0.13±0.037) mg/L。与对照组相比, 各链霉素浓度处理下叶绿素a的含量显著降低。最大光化学效率(φP₀)、可变荧光(F_v)、PSⅡ的潜在活性(F_v/F₀)、单位面积上有活性的反应中心(RC/CS₀)、以吸收光能为基础的性能指数(PIabs)及反应中心吸收的光能用于电子传递的量子产额(φE₀)均随着链霉素浓度的升高而降低。然而, 单位叶绿素最大荧光(F_m/Chl. a)、每个有活性的反应中心吸收的光能(ABS/RC)和热耗散(DI₀/RC)则随着链霉素浓度的升高而增加。当链霉素浓度大于0.1 mg/L时, 叶绿素荧光动力学曲线出现K点的出现。结果表明链霉素可能通过抑制光合系统Ⅱ(PSⅡ)的电子传递和减少有活性的反应中心来影响念珠藻的生长, 也暗示了高浓度链霉素对藻类的生长具有抑制作用。     

磷浓度对海水钝顶螺旋藻生长代谢的影响

磷元素对微藻的生长代谢具有重要作用。为了探究磷源浓度调控海水螺旋藻主要代谢产物合成积累的可行性。以改良的Zarrouk海水培养基为基础,通过设置5种K2HPO3浓度(0.005-0.04 g/L),分析不同磷浓度对海水螺旋藻的生长及生理生化指标的影响。结果显示,海水螺旋藻生物质浓度和蛋白质含量随着磷源浓度的升高而增加,0.04 g/L处理组达到最大值,分别为0.48±0.02 g/L和59.23±0.61%DW;总多糖含量随着磷源浓度增加先显著下降,0.005 g/L处理组含量最高(25.96±1.61%DW);C-藻蓝蛋白、别藻蓝蛋白和总藻胆蛋白含量随着磷源浓度增加,先升后降,0.03 g/L处理组含量最高,分别为14.56±0.99%DW、4.21±0.19%DW和18.77±0.39%DW;叶绿素a与类胡萝卜素含量随着磷源浓度的增加而升高,最高含量分别为1.01±0.01%DW和0.35±0.02%DW;而磷源浓度的变化对总脂含量和脂肪酸组成总体上无显著影响(P0.05)。低磷源浓度有利于多糖积累,高磷源浓度则促进蛋白质和藻蓝蛋白、叶绿素和类胡萝卜素的合成,通过磷源调节可有效定向诱导海水螺旋藻主要高值化产物的合成积累。     

高温对两种卡帕藻的酶活性、色素含量与叶绿素荧光的影响

在室内采用静置培养法,以25℃为对照,研究高温(32℃、35℃和40℃)对长心卡帕藻Kappaphycus alvarezii与异枝卡帕藻K.striatum的硝酸还原酶(NR)和过氧化物酶(POD)活性、叶绿素a和藻红蛋白含量的影响,并采用调制叶绿素荧光技术,测定高温处理后2种藻的叶绿素荧光参数变化趋势.结果表明:高温对2种卡帕藻的NR和POD活性有显著影响.二者的NR活性均在35℃时最低,32℃时最高;异枝卡帕藻的POD活性在35℃时最高,而长心卡帕藻的在35℃时最低.在25-40℃之间,随着温度升高,异枝卡帕藻的叶绿素a含量逐渐减少,藻红蛋白含量先降后升,35℃时最高,而长心卡帕藻的两种色素含量皆在25℃时最高.在32-40℃条件下,随着温度升高,2种藻的实际光合效率(Y)和相对光合电子传递速率(ETR)明显下降,温度越高,下降程度越大;短期高温可刺激2种卡帕藻的光合活性增强,随着处理时间延长,异枝卡帕藻的光合活性下降,但差异不显著,而长心卡帕藻的光合活性显著下降.综合上述指标,显示32℃以上高温对2种卡帕藻产生胁迫,异枝卡帕藻对热胁迫的耐受力明显强于长心卡帕藻.     

共生与非共生爪哇伪枝藻对高温胁迫的响应

研究以自由生长的爪哇伪枝藻(Free-living S. javanicum, fs)和分离自地衣的爪哇伪枝藻(Symbiotic S. javanicum, ss)为研究对象, 探究了不同生长状态爪哇伪枝藻对高温(45℃)胁迫的响应。结果发现在高温胁迫下, 爪哇伪枝藻光合活性、叶绿素a及类胡萝卜素含量下降; 丙二醛(MDA)、胞外多糖及可溶性蛋白含量上升。在高温处理下, 与fs相比, ss光合活性下降较慢, 且高温处理后ss的叶绿素a及类胡萝卜素含量也明显高于fs。高温处理下, 与fs相比, ss的MDA含量和增长速度均较低; 并且在面临高温胁迫时, ss能够更快的分泌胞外多糖和可溶性蛋白质, 从而在一定程度上达到自我保护的目的。研究结果表明, 在暴露于高温胁迫时, 相较于自由生长状态, 来自地衣的爪哇伪枝藻具有更高的自我保护效率。     

念珠藻葛仙米生理生化特性对不同低温胁迫的响应

研究了不同培养温度下对念珠藻葛仙米的生长和相关生理生化特性的变化.结果表明,低温抑制葛仙米的生长,在2℃～5℃低温下其生长甚至完全停止;在10℃低温胁迫下,其生长延滞期变长,其后仍能保持正常生长.低温胁迫下,葛仙米光合系统II(PSII)的光合效率(Fv/Fm)的变化趋势与生长曲线相似;细胞电解质渗透率在低温胁迫初期尚能保持比较低的水平,但随着时间延长而升高;可溶性糖和还原性糖含量的变化则随胁迫加剧有不同程度升高.可溶性蛋白含量则在低温下保持比较低的水平.这些结果表明,低温对葛仙米的生长和光合作用具有抑制作用,但葛仙米也表现出了一定的抵抗低温胁迫的能力,并通过调节细胞膜的渗透性、重新合成低温适应调节物质(如总糖和可溶性糖等)来减少低温伤害,从而适应低温胁迫.     

增补UV-B辐射对菥蓂生理特性及次生代谢产物的影响

为了解药用植物菥蓂(Thlaspi arvense)在紫外线(UV-B)辐射增强下生长及响应规律,以2月龄菥蓂幼苗为研究对象,在自然光照基础上人工增补3.26μW·cm^-2(T1)和9.78μW·cm^-2(T2)2种不同辐射强度处理,以自然光照下生长的菥蓂幼苗为对照,研究菥蓂幼苗中光合指标和叶绿素荧光参数、光合色素(叶绿素a和b)含量、渗透调节物质(丙二醛、可溶性蛋白、可溶性糖和脯氨酸)含量、抗氧化酶(超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化氢酶)活性和总黄酮、总酚和黑芥子苷等次生代谢产物含量对不同UV-B辐射强度的响应。结果表明：2种辐射强度下净光合速率、气孔导度、蒸腾速率、胞间二氧化碳摩尔分数、最大荧光(F_m)、PSⅡ最大光化学效率(F_v/F_m)和PSⅡ潜在光化学效率(F_v/F_o)均随辐射强度增大而降低;叶绿素a和叶绿素b、可溶性蛋白、可溶性糖和脯氨酸等渗透调节物质、超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过...     

一株红假单胞菌的分离及生理特性研究

光合细菌在水处理和水生态修复领域应用前景广阔, 对其生理特性研究具有重要价值。从武汉东湖分离得到一株不产氧光合细菌PUF1, 通过对菌落形态、细胞超微结构、特征吸收光谱以及系统发育等分析, 初步确定为红假单胞菌属(Rhodopseudomonas sp.)紫色非硫光合细菌。PUF1细胞呈直的或稍弯曲的杆状, 长3.05—10.06 μm, 直径0.32—0.68 μm, 具有片层膜结构。PUF1培养物呈深紫红色, 主要色素为细菌叶绿素a (Bchl. a)和类胡萝卜素。初始pH 6.0—8.0, 光照强度500—3000 lx, 稳定期细菌生物量无显著差异, 但培养液pH>8.0会显著抑制PUF1最大光量子产量(F_v/F_m)。试验进一步研究了细菌不同生长阶段粗蛋白含量、ATP酶(ATPase)活性及F_v/F_m的变化规律。结果表明, PUF1不同生长阶段其蛋白含量有所差异, 以稳定期为最高(>60%), 而ATPase活性随培养时间的延长而逐渐降低。此外, PUF1光合作用与其生长状态也有一定的关系, 具体表现为细菌生长周期内F_v/F_m变化规律适用单峰高斯模型, 且以对数期F_v/F_m为最高。研究结果可为光合细菌生理生化特性研究提供重要的参考依据。     

葛仙米光合活性对盐胁迫的反应

收集人工条件下培养的葛仙米球形群体,以不同浓度的NaCl溶液处理,当浓度超过0.2mol/L后,叶绿素a荧光的可变部分(Fv)与最大荧光(Fm)之比值(Fv/Fm)与NaCl浓度呈负相关,光合放氧速率也随着NaCl浓度升高而降低。这两者随氯化钠浓度升高而降低的趋势均呈现出两个阶段性:低NaCl浓度时的缓慢降低阶段和高NaCl浓度时的快速降低阶段。Fv/Fm比值的转折点在0.2mol/L,而光合放氧速率的在0.4mol/L,后者与海水的浓度接近。呼吸作用几乎不受NaCl的影响。光系统I(PSI)和光系统II(PSII)活性随着NaCl浓度的提高均有降低。     

草甘膦对可食用蓝藻葛仙米生长和生理的影响

葛仙米（N．sphaeroides）的产量和产地面积逐年减少,这可能与当地广泛使用除草剂草甘膦有关。为此,本文测定了不同浓度（0．15、0．30、0．45、0．6mmol／L）的草甘膦处理的葛仙米的颗粒大小、干重、叶绿素荧光、叶绿素浓度。所有测量参数与浓度和时间显著相关：0．15mmol／L处理组的颗粒直径较对照组小15％（2d后）;叶绿素a浓度和最大量子产率（Fv／Fm）在最高浓度组（0．6mmol／L）4d后开始受到影响;第8天,相对生长速率（以干重计算,大于0．15mmol／L）、光合作用活性（大于0．3mm01／L）均受显著抑制,其中0．15mmol／L处理组相对生长下降60％,而更高浓度处理组出现负生长,0．6mm01／L组藻体漂白死亡。结合实验结果,文章讨论了草甘膦的毒性机理及其对葛仙米（N．sphaeroides）的潜在影响。     

Growth kinetics of 1–2 mm and 3–4 mm colonies of Nostoc sphaeroides (Cyanophyta) in outdoor culture

Nostoc sphaeroides Kützing was cultivated in paddlewheel-driven raceway ponds and the growth kinetics of 1-2 mm and 3-4 mm colonies of N. sphaeroides was studied. The biomass productivities in 2.5 m(2) raceway ponds inoculated with 1-2 mm and 3-4 mm colonies were 5.2 and 0.25 g dry wt m(-2) d(-1), respectively. Furthermore, differently sized colonies showed different relative water content, total soluble carbohydrates, chlorophyll a content and density of filaments. This is the first report on mass culture of N. sphaeroides under outdoor conditions.     

The relationship between the distribution of worker sizes and new worker production in the ant Formica neorufibarbis

While it is commonly assumed that variation in worker sizes within a single ant colony increases colony efficiency, there is little causal evidence of a link between worker size variation and colony performance. I tested whether the range of worker sizes within colonies of the ant species Formica neorufibarbis affected new worker production. Removing large workers from colonies lowered the rate of new worker production. A study of unmanipulated colonies indicated that colonies did not maintain a full range of worker sizes; mean worker head widths varied from 0.89-1.24 mm. Colonies naturally missing large workers did not have lower rates of worker production, suggesting that the relative size, not the absolute size, of workers within colonies was important. These are the first results to directly link the range of worker sizes to a component of colony fitness in a natural setting.     

Living in a Phaeocystis colony: a way to be a successful algal species

Evidence is provided showing that in two species of Phaeocystis (P. globosa and P. pouchetii) the colonial cells possess a much higher growth rate than the single cells when grown under identical conditions. Based on the DNA-cell-cycle method gross growth rate of colony cells exceeded those of co-occurring single cells by a factor 1.5 up to 3.8. The dominance of colonies in blooms of Phaeocystis can therefore be primarily due to their significantly high growth rate allowing a rapid bloom formation.Both Phaeocystis species showed ultradian growth but differed in timing of the initiation of the second DNA replication phase. In both species the first DNA-replication period started at the end of the (local) light period and was completed in the early dark period. In P. globosa this was immediately followed by the second DNA-replication period (first half of the dark period). In P. pouchetii this process was delayed by ca. 12 h until the middle of the light period (local noon).Flow cytometric analysis of the cell size and chlorophyll fluorescence showed little variation in colony and single cells of P. pouchetii. In contrast, colonies of P. globosa showed often the presence of two cell morphs, co-occurring in the same colony. The size of both morphs was identical but they differed in chlorophyll fluorescence up to a factor 4. In general the high chlorophyll cell morph dominated (>70% of the total colony cells). Both colony cell morphs were observed in cultures, mesocosms differing in N/P ratio but also in the field.     

Corals as light collectors: an integrating sphere approach

An integrating sphere was used to estimate the fraction of the incident quantum flux absorbed by a coral colony placed within it. This method allows one to examine the in vivo light absorption of intact coral colonies. We used this method to study effects of colony morphology, size, and photoacclimation status on the light harvesting efficiency by the zooxanthellae. Light absorption per unit of coral surface area decreased with increase in colony size, with a clear effect of different coral morphologies. In branched colonies, shading among branches reduced the absorbed light per unit area and per zooxanthellae. Photoacclimation to low light resulted in increased cellular chlorophyll concentrations in the zooxanthellae. In shade acclimated colonies, areal chlorophyll concentrations increased significantly, leading to more overlap among the optical cross-sections of pigments within cells and mutual shading among cells. These package effects showed up as a decrease in the in vivo, chlorophyll-a specific, spectral average, effective optical cross-section, a*. An integrating sphere is a useful tool for collecting optical information on corals.     

Development of the photosynthetic apparatus during light-dependent greening of a mutant of Chlorella fusca

The formation of chlorophyll, cytochrome f, P-700, ribulose bisphosphate carboxylase as well as photosynthesis and Hill reaction activities were tested during the light-dependent greening process of the Chlorella fusca mutant G 10. Neither chlorophyll nor protochlorophyllide was detected in the darkgrown cells. When transferred to light the mutant cells developed chlorophyll and established its photosynthetic capacity after a short lag phase. In the in vivo absorption spectra a spectral shift of the red absorption peak position from 674 to 680 nm was indicated during the first 3 h of greening. Cytochrome f was already present in the dark-grown cells, but during the greening phase a threefold increase in the cytochrome f content could be seen. At the early stages of greening a characteristic primary oscillation in the content of cytochrome f was observed. P-700 was lacking in the dark and during the first 30 min of illumination. From the first to the second h of light a forced synthesis of P-700 took place and the time-course curve for the ratios of P-700/chlorophyll rose to a sharp maximum. The synthesis of P-700 started together with photosystem I activity and showed similar kinetics. We found the simultaneous appearance of photosystem II, photosystem I, and photosynthetic activities 30 min after the beginning of the illumination. Based on chlorophyll content they attained maximum activity after 2 h of light, but at this time photosystem I capacity proved to be remarkably higher than photosynthetic and photosystem II activities. Highest carboxylase activity existed in darkgrown cells. During the greening process the activity of the enzyme decreased continuously. After 2 h of illumination chlorophyll synthesis partially served to increase the size of the photosynthetic unit, which consequently led to a decrease in the light energy needed to saturate photosynthesis and also to a decrease of photosynthetic rate based on chlorophyll content.Abbreviations Chl chlorophyll - Cyt f cytochrome f - DPIP 2,6-dichlorophenolindophenol - EDTA ethylenediaminetetraacetic acid - GSH glutathione - LH light-harvesting - PS photosystem - RuBP ribulose bisphosphate     

LIGHT ACCLIMATION IN PORPHYRIDIUM PURPUREUM (RHODOPHYTA): GROWTH,PHOTOSYNTHESIS, AND PHYCOBILISOMES1

Acclimation to three photon flux densities (10, 35, 180 μE.m^?2.s^?1) was determined in laboratory cultures of Porphyridium purpureum Bory, Drew and Ross. Cultures grown at low, medium, and high PPFDs had compensation points of <3, 6, and 20 μE-m^?2.s^?1, respectively, and saturating irradiances in the initial log phase of 90, 115, 175 μE.m^?2.s^?1 and up to 240 μE.m^?2.s^?1 in late log phase. High light cells had the smallest photosynthetic unit size (phycobiliproteins plus chlorophyll), the highest photosynthetic capacity, and the highest growth rates. Photosystem I reaction centers (P700) per cell remained proportional to chlorophyll at ca. 110 chl / P700. However, phycobiliprotein content decreased as did the phycobilisome number (ca. 50%) in high light cells, where as the phycobilisome size remained the same as in medium and low light cells. We concluded that acclimation of this red alga to varied PPFDs was manifested by the plasticity of the photosystem II antennae with little, if any, effect noted on photosystem I.     

遮荫对半夏叶片光合色素与保护酶活性的影响

对半夏进行不同程度遮荫处理,研究了其生长过程中叶组织的光合色素含量、叶绿素a/b值、保护酶体系(SOD、POD、CAT)活性和丙二醛(MDA)含量的变化及其生理特性.结果表明:不同处理的半夏在生长过程中,光合色素的含量呈先升后降的趋势;与全光照相比,遮荫处理的叶绿素含量较高,叶绿素a/b值较低,类胡萝卜素含量在生长发育中早期较低而后期较高;SOD、POD、CAT活性呈由低到高再降低的趋势,MDA含量持续升高;遮荫处理的SOD、POD活性和MDA含量均低于全光照处理,CAT活性则表现为先高于后低于全光照处理.适度的遮荫可以提高半夏叶绿素的含量,降低膜系统受到的伤害,改善半夏的倒苗状况,为半夏叶片的生长提供较好的环境.