鼠尾藻生长与生殖的权衡

2009年7月初至2009年9月中旬对烟台长岛县望福礁附近水域鼠尾藻(Sargassum thunbergii)进行了生态学调查。实验设立固定采样地点通过随机采样以及现场标记测量的方法观测了鼠尾藻的生长与生殖情况。结果表明:(1)鼠尾藻生殖始于7月初,8月初为高峰期,此间87%的藻体产生生殖托;(2)藻体长度对成熟比例和生殖力均有显著的影响,藻体成熟具有大小依赖性;(3)营养组织生物量大的鼠尾藻群体生殖组织生物量也相对较大,生殖期间营养组织生长和生殖组织生长呈异速关系;(4)成熟藻体在有性生殖高峰期过后,生长率下降,而始终未成熟的藻体则持续生长(生长率0)。以上结果表明,在鼠尾藻的生活史中存在着生长与生殖的权衡。     

中国沿海鼠尾藻遗传多样性分析

鼠尾藻是我国沿海重要经济海藻,本文采用AFLP分子标记技术对我国辽宁、山东和浙江沿海的野生鼠尾藻共120个个体进行了遗传多样性分析.5对引物共得到340个位点,多态性位点比例分别为旅顺盐场群体82.31%、大连长海群体78.97%、山东海阳群体91.03%和浙江洞头群体94.87%,平均杂合度分别为0.2088、0.1862、0.2505和0.2736.Shannon多样性指教分别为0.3273、0.2974、0.3911和0.4236,群体间的遗传距离在0.0301～0.1437之间.分析结果表明,4个群体的遗传多样性水平均出现了一定程度的降低.     

鼠尾藻对赤潮异弯藻和中肋骨条藻的抑制作用

通过共培养的方法,研究了鼠尾藻（Surgassum thunbergii）培养水的过滤液、新鲜组织、干粉末、水溶性抽提液对赤潮异弯藻（Heterosigma akashiwo）和中肋骨条藻（Skeletonema costatum）生长的抑制效应,建立了分隔共培养系统并证明了抑制物质的存在,排除了细胞直接接触抑制的可能性.结果表明,在共培养实验中,鼠尾藻新鲜组织、干粉末及水溶性抽提液对赤潮异弯藻和中肋骨条藻的生长具有显著的抑制作用,且在较高浓度下对两种赤潮微藻的生长具有致死效应.在一次性及半连续培养方式下,鼠尾藻培养水过滤液对赤潮异弯藻的生长无抑制效应,而对中肋骨条藻的生长具有显著的抑制效应.     

五种淡水微藻的适宜培养温度和光照强度

从淡水中分离得到绿球藻(Chlorococcum sp.)SHOU-F3、纤维藻(Ankistrodesmus sp.)SHOU-F33、小球藻(Chlorella sp.)SHOU-F46、空星藻(Coelastrum sphaericum)SHOU-F10和栅藻(Scenedesmus sp.)SHOU-FX,分别在光照培养箱中研究了温度、光照强度对5种微藻增殖的影响,并分析了5种微藻的细胞组成。结果表明:绿球藻SHOU-F3、纤维藻SHOU-F33、小球藻SHOU-F46、空星藻SHOU-F10和栅藻SHOU-FX的最适生长温度分别为29.8、23.5、31.4、34.4和24.7℃;最适光照强度分别为16、119、42、82和106μmol·m-2·s-1;在适宜培养条件下,绿球藻SHOU-F3的色素、蛋白以及总糖的百分含量最高,纤维藻SHOU-F33的脂肪百分含量最高。     

盐度、温度和光照强度对针叶蕨藻的生长及光合活性的影响

为探究环境因子对针叶蕨藻（Caulerpa sertularioides）生长的影响,对不同盐度、温度和光照强度下针叶蕨藻的生长和叶绿素荧光参数进行了研究。结果表明：藻体日特定生长率（SGR）、最大光量子产量（F_v/F_m）、实际光合效率（Yield）、电子传递速率（ETR）和光化学淬灭（qP）随盐度升高呈先上升后下降的变化趋势,非光化学淬灭（qN）则呈相反的变化趋势,藻体光合活性和固碳效率在盐度27.5‰时达到最高,且与25‰和30‰盐度的差异显著（P<0.05,n=3）。藻体SGR、F_v/F_m、Yield、ETR和qP随温度升高而下降,qN则相反,藻体光合活性和固碳效率在26℃下达到最高,且与28℃和30℃的差异显著（P<0.05,n=3）。藻体的SGR、F_v/F_m、Yield、ETR和qP随光照强度升高呈先上升后下降的变化趋势,qN则相反,且在18.75 μmol/（m²·s）弱光照下出现轻微光抑制,藻体生长、光合活性及固碳效率在光照强度25.00 μmol/（m²·s）时达到最高,但与18.75和31.25 μmol/（m²·s）的差异不显著（P>0.05,n=3）。因此,针叶蕨藻在27.5‰盐度、26℃和25.00 μmol/（m²·s）光照强度下生长最快且光合作用能力最高。     

温度对谷皮菱形藻生长及其理化成分的影响

考察了不同温度对谷皮菱形藻生长及其理化成分的影响。结果表明:温度在10℃或30℃条件下不利于细胞生长,同时也不利于胞内理化成分的积累。在20℃条件下细胞密度、叶绿素含量、胞内蛋白、胞外多糖及胞内多糖达到最大值。谷皮菱形藻的最适生长温度为20℃,10℃可以作为种质保存的温度。     

光强及氮浓度对丝状绿藻双星藻生长及生化组成的影响

[背景]环境因子和营养因子对微藻的生长和生化组成都有显著的影响,其中光强和氮浓度是最重要的两个条件。[目的]研究不同光强和初始氮浓度对丝状绿藻-双星藻(Zygnema sp.)生长及生化组成的影响。[方法]采用改良的BBM培养基,设置了两组光强[100μmol/(m²·s)和300μmol/(m²·s)]和6种初始氮浓度(3、6、9、12、15和18 mmol/L)在柱状光生物反应器中对双星藻进行培养。[结果]在高光强条件下[300μmol/(m²·s)],12 mmol/L初始氮浓度最有利于双星藻生物质的积累,其最高生物量可以达到6.60 g/L,而初始低氮浓度(3 mmol/L)则促进了油脂和脂肪酸的积累,油脂最高含量占干重的32.13%,且脂肪酸组成主要包括棕榈酸(C_16:0)、油酸(C_18:1)、亚油酸(C_18:2)和亚麻酸(C_18:3),其中油酸含量最高达到总脂肪酸含量的55.01%;在低光强条件下[100μmol/(m     

附着基材质对鼠尾藻幼苗附着及生长的影响

附着基是影响幼苗人工繁育的重要因素。为了选择有利于鼠尾藻幼苗附着和生长的附着基, 该研究利用六种不同材质的附着基(水泥块、砖块、岩块、扇贝壳、化纤布、尼龙绳)分别进行了人工采苗、车间培育及野外增殖等实验并测定了附苗效率、附苗密度、出苗率及相对生长率等生物学参数。结果显示, 静水采苗条件下, 各种附着基上受精卵附着效率为60.3% ―73.6%, 采苗期附着基材质影响不显著; 流水暂养20 d 后, 扇贝壳附着基的附苗密度明显下降(32±10 ind·cm^–2, p<0.05), 其它附 着基的附苗密度变化不明显; 野外移植30 d 后, 不同附着基上出苗率和幼苗长度变化显著(p<0.05), 其中化纤布附着基上出苗率和幼苗长度值最高(60.6±19.7 %, 7.3 ± 2.6 mm), 扇贝壳附着基上出苗率和幼苗长度值最低(6.5±11.3 %, 2.8 ± 1.6 mm)。因此,附着基材质对鼠尾藻受精卵附着影响不显著, 但附着基表面的特殊结构很可能会影响幼苗固着和生长。实验表明, 使用化纤布、水泥块、砖块附着基培育幼苗效果较好。     

连续性干出对孔石莼生长和生化组成的影响

以孔石莼(Ulva pertusa)为试验材料,研究了连续性干出对其生长和生化组成的影响.结果表明:与对照组(0 h)相比,短时间的连续性干出促进孔石莼生长,表现在特定生长率( SGR)升高、叶绿素a含量上升;随着连续性干出时间延长,孔石莼SGR、叶绿素a、蛋白质含量下降,叶绿素b、可溶性糖含量上升;叶绿素a/b比值变化和可溶性糖含量变化有利于抵抗干出胁迫.     

不同光照强度和湿度以钗石斛生长的影响

为了系统地研究不同光照强度下湿度以金钗石斛（Dendrobium nobile)生长的影响,在金钗石斛分蘖期,于80μmol.m^-2.s^-1、160μmol.m^-2.s^-1、320μmol.m^-2.s^-1、640μmol.m^-2.s^-1的不同光强下,各设置5个温度（15℃、20℃、30℃、35℃）梯度对石斛进行处理。结果表明：石斛的生长与代谢随温度由低到高,表现出弱－强－弱的变化规律℃;80μmol.m^-2.s^-1与640μmol.m^-2.s^-1的中、强光照下,25℃处理石斛的生长优势尤为明显;不同光强下,石斛鲜重的大多以25℃处理更快,繁殖力则以20℃和25℃处理较高;各光强下的MDA含量随温度升高而先降后升,且均以25℃最低;可溶性蛋白质、可溶性总糖及叶绿互含量则表现出随温度由低到高而先增后减的趋势,其含量最高点均出现在25℃左右;净光合速率和叶绿素含量随光强和温度的变化趋势基本一致;各种光强下的暗呼吸速率均随温度升高而增大。因此,在不同的光照条件下,石斛生长的适宜温度均在25℃左右。光温处理引起石斛生理生化过程明显的相应变化表现出：高温和弱光照条件有利于石斛的株高增长,但不利于产量和质量提高;石斛的生长与MDA含量呈显著负相关（r80=-0.9082、r160=0.8892、r320=-0.8075、r640=-0.8586),与可溶性糖含量一定正相关（r80=-0.7673、r160=0.8892、r320=0.8179、r640=0.9278）,并且石斛的生长与可溶性蛋白含量、叶绿素含量、光合速率之间的变化趋势基本一致。     

Photoacclimation characteristics of Sargassum thunbergii germlings under different light intensities

The photosynthesis and growth responses of Sargassum thunbergii germlings to different light intensities (10, 60, and 300 μmol photons m^?2 s^?1) were investigated. Maximum photochemical efficiency (F _v/F _m), rapid light curves (RLCs), and photochemical and non-photochemical quenching (qP and NPQ) were estimated by a pulse amplitude-modulated fluorometer. The photosynthesis of S. thunbergii germlings exhibited different properties to optimize light capture and utilization. The excitation pressure (1???qP) was rapidly increased to approximately 0.27 showing that germlings responded to high light by chronic photoinhibition with an accumulation of closed reaction centers, which ultimately resulted in a slow growth. This was accompanied by a reduced F _v/F _m with time and a development of high capacity for NPQ. Although F _v/F _m in moderate-light germlings did not fully recover overnight, germlings demonstrated a less severe chronic photoinhibition considering the reduced degree of excitation pressure accumulation of approximately 0.15. The relative stability of photosynthetic capacity (rETR_max, E _k, and α) could endow germlings with the highest relative growth rate (RGR) of approximately 9.3 % day^?1 in moderate light. By contrast, low-light germlings demonstrated high F _v/F _m and F _o, corresponding high α collectively suggested greater efficiency of light absorption and energy transformation. Sustained increases in electron transport capacity (rETR_max and E _k) occurred in low-light germlings, which resulted in a stable RGR of over 8.2 % day^?1. Consequently, S. thunbergii germlings are considered to prefer low light regimes and have a relative capacity of moderate and high light tolerance. However, the light acclimation to oversaturating conditions is at the cost of slow growth to maintain survival.     

温度、光照和盐度对2株曼氏骨条藻生长及脂肪酸组成的影响

研究温度、光照、盐度对2株曼氏骨条藻（Skeletonema munzelii）SM-1、SM-2生长、总脂含量及脂肪酸组成的影响,以确定其生长及油脂、多不饱和脂肪酸积累的最适生态条件。在实验室智能光照培养箱内不充气培养控制条件下,采用单因子试验分别研究了不同温度（10、15、20、25和30℃）、光照强度（20、40、60、80、100和120μmol/m2·s）、盐度（10、15、20、25、30、35和40）对2株藻的生长、总脂含量及脂肪酸组成的影响。结果表明：不同温度、光照强度及盐度对2株藻的生长、总脂及脂肪酸含量影响均有显著影响（P〈0.05）。藻株SM-1生长的最适温度为25℃,最适光强60μmol/m2·s,最适盐度30,而低温（10~15℃）,低光照（20μmol/m2·s）,低盐度（盐度15）更有利于总脂及PUFA的积累。SM-2生长的最适温度为20℃,最适光强60μmol/m2·s,最适盐度30,而低温（10~15℃）,低光照（20μmol/m2·s）更有利于其总脂及PUFA的积累,低盐（盐度15）则更有利于PUFA的积累。因此在实际生产中,2株藻可先在最适条件下培养以增加生物量,后转至利于PUFA积累的条件下提高PUFA产量。     

温度、盐度、光照对海洋卡盾藻生长和产毒的影响

在正交试验条件下,分析了盐度、温度、光照强度对海洋卡盾藻生长和产毒的影响.结果表明：在盐度22、33、45和温度20 ℃、25 ℃、30 ℃以及光照强度2000、3000、4500 lx条件下,三因素对海洋卡盾藻生长的影响均不显著,盐度是影响海洋卡盾藻产毒的主要因子;盐度45、温度30 ℃、光照2000 lx下海洋卡盾藻的比生长速率最大,盐度22、温度20 ℃、光照4500 lx下海洋卡盾藻的产毒能力最强;低盐条件不利于海洋卡盾藻的生长,但有利于溶血毒素的合成;当海洋卡盾藻生长受到限制时,其溶血毒素合成增多.     

Effects of nutrient and light limitation on the biochemical composition of phytoplankton

Three marine phytoplankters (Isochrysis galbana, Chaetoceros calcitrans andThalassiosira pseudonana), commonly used in the culture of bivalve larvae, were grown in batch or semi-continuous cultures. Changes in protein, carbohydrate, lipid and some fatty acids were measured as growth became limited by nitrogen, silicon, phosphorus or light. Under N starvation (2 d) the % lipid remained relatively constant, while% carbohydrate increased and% protein decreased in all 3 species compared to cells growing under no nutrient limitation. Under Si starvation (6 h) there was no change in lipid, protein or carbohydrates. The amount of two fatty acids, 20 : 53 and 22 : 63 remained relatively constant under N, P and Si starvation, exept for a sharp drop in the cells of P-starvedT. pseudonana. However, there were pronounced species differences withI. galbana containing significantly less 20 : 5 3 thanC. calcitrans orT. pseudonana. Under light limitation the amount of lipid per cell showed no consistent trend over a range of irradiances for all 3 species. The amount of N per cell (an index of protein content) as a function of irradiance, was relatively constant forI. galbana andT. pseudonana, while the amount of N per cell was lower under low irradiances forC. calcitrans. These examples of changes in protein, carbohydrate, lipid and certain fatty acids under nutrient (N, Si or P) or light limitation, emphasize the importance of knowing the phase (e.g. logarithmic vs stationary) of the growth curve in batch cultures, since the nutritional value of the phytoplankters could change as cultures become dense and growth is terminated due to nutrient or light limitation.Presented at the XIIIth International Seaweed Symposium, University of British Columbia, Vancouver, Canada, August 1989.     

Effects of temperature and growth phase on lipid and biochemical composition of Isochrysis galbana TK1

The lipid and biochemical composition of the haptophyte Isochrysis galbana TK1 was examined. Cultures were grown at 15 °C and 30 °C, and harvested in the exponential and early stationary growth phases. Carbohydrate and protein content varied at the two culture temperatures and growth phases. The highest protein content was found at the exponential growth phase at 15 °C, and the highest carbohydrate content was found at the stationary phase at the same culture temperature. Lipid accumulated in the stationary growth phase and its content was higher at 30 °C than at 15 °C regardless of the growth phase. The neutral lipids were the major class of lipid found in all the cultures. The stationary phase culture had a higher proportion of neutral lipids than the exponential phase culture and the proportion decreased slightly when culture temperature was increased from 15 °C to 30 °C. Phospholipid levels remained constant at the two temperatures, but slightly decreased in the stationary phase. Glycolipids in the exponentially growing cells were higher than those from stationary growth phase and increased with temperature. Polyunsaturated fatty acids (PUFAs) predominated in glycolipids and phospholipids. Cells grown at 15 °C contained higher proportion of 18:3 (n–3) and 22:6 (n–3) with a corresponding decrease in 18:2 (n–6), monounsaturated and saturated fatty acids. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of temperature and light intensity on the growth rate of Synura sphagnicola

The chrysophyte Synura sphagnicola Korsch. was isolated froma hypolimnion bloom in a Canadian Shield lake and its abilityto grow at low light and temperature was studied. Growth saturatinglight was much higher than in situ intensities and independentof temperature while compensation intensity decreased with decreasingtemperature. Optimum temperature decreased with decreasing lightintensity. While optimum temperature was lower than generallyseen among temperate water algae, compensating and saturatinglight were similar to those seen in other algae. At low lightand temperature, the growth rate of S. sphagnicola was lowerthan the growth rates under similar conditions of other algae,and appeared insufficient to account for the net rate of chlorophyllaccumulation observed in the bloom from which the alga was isolated.     

Effects of variation in temperature and light intensity at different times on growth and yield of spring wheat

Spring wheat grown in pots outdoors was transferred to growth rooms for various periods to study the effect of increasing the temperature from 14-4 to 20-3 ^oC (Expt 1) or from day/night values of 15-0/15-2 to 20-0/15-2 ^oC (Expt 2) and of increasing the amount of visible radiation in a 16 h day from 424 to 792 J cm^-2 (Expt 1) or 374 to 740 J cm^-2 (Expt 2). There were no interactions between temperature and radiation. In Expt 1 neither the increase in temperature nor extra radiation, applied for 14 days immediately after the appearance of double ridges on the stem apex, or 14 days later, increased grain yield at maturity. Warmth early, but not late, increased dry weight, leaf area and the number of floret primordia immediately after treatment, but these effects had disappeared by anthesis, 30 days later. Dry weight but not leaf area was increased by extra radiation but the effects had disappeared 2 wk after treatment. An increase in temperature imposed for 16 days starting 5 or 21 days after anthesis (Expt 2) increased dry weight of the ear and decreased that of the rest of the plant immediately after treatment, and decreased leaf area at all times. When plants from the two temperatures were put together in the same conditions, ear growth of plants that had been in the warm was slower than that of plants from the cold treatment, so that the difference in ear weight observed after 16 days of treatment reversed and grain yield was decreased by warmth applied in either period; the component of yield decreased by warmth was grain size. Additional radiation in either post-anthesis period increased dry weight of all parts of the plant and had negligible effects on leaf area. Final grain yield was increased by c. 15% because the individual grains were larger. Early treatment also increased grain number slightly. The effects of treatment during the two post-anthesis periods were similar in size, and additive.     

Effects of light intensity distribution on growth of Rhodobacter capsulatus

For cultivation of photosynthetic cells under defined light intensity distributions, the repeated batch culture, in which a part of culture broth containing grown cells was repeatedly replaced at predetermined time intervals with a fresh medium to keep the cell concentration constant at an initial value, was employed. By use of this method the effects of the light intensity distribution on the growth characteristics of Rhodobacter capsulatus were studied. Unexpected decreases in the specific growth rate were observed in culture of R. capsulatus at high cell concentrations and a long light path length. Big differences in the light intensities of lightly and darkly illuminated portions in photobioreactors, which reflects the light intensity distribution, seemed to cause this phenomenon, which must be taken into consideration for stable growth of photosynthetic cells.