3株溶藻细菌溶藻特性的初步研究

对3株溶藻细菌L7、L8和L18溶解水华鱼腥藻(Anabaena flos-aquae FACHB-245)的溶藻方式、溶藻活性代谢产物的溶藻特性进行了研究。3株菌都为间接溶藻,产生具有热稳定性的、对水华鱼腥藻有较强溶藻效果的活性代谢产物。L8的溶藻效果与藻液中投加溶藻活性代谢产物的浓度呈正相关。处于衰减期的L8,其溶藻活性代谢产物的溶藻效果好于对数生长期和稳定期。在不同pH值条件下进行溶藻实验,当pH值为8.5±0.1时,L7溶藻活性代谢产物的去除率达到85.78%;当pH值为10±0.2时,L8和L18溶藻活性代谢产物的去除率分别达到92.84%和78.72%;由7×108cells/mL的L8菌液获得的无菌滤液,当投加量<30%时,对水华鱼腥藻的生长具有促进作用。     

氮磷对微囊藻和栅藻生长及竞争的影响

为了揭示不同营养条件下,藻类优势种的形成规律,选取了3种具有代表性水体的营养盐浓度,对于蓝藻水华的常见种铜绿微囊藻和绿藻水华的常见种四尾栅藻进行了竞争实验.通过竞争抑制参数对相互间的竞争关系进行了分析.结果表明,在贫营养水平下,栅藻的存在能够刺激微囊藻的生长,N/P值越小,刺激作用越明显,微囊藻也能刺激栅藻的生长;富营养水平下,竞争抑制作用与N/P有关;超富营养水平下,栅藻对微囊藻的抑制能力约为微囊藻对栅藻的抑制能力的3倍,N/P值的变化对竞争抑制作用的影响不明显.在较低氮磷浓度的水体中,微囊藻容易成为优势种,而在较高的氮磷浓度的水体中,四尾栅藻更容易成为优势种.     

光照、温度和营养盐对滇池微囊藻生长的影响

研究了光照、温度与营养盐对滇地铜绿微囊藻（Ｍｉｃｒｏｃｙｓｔｉｓａｅｒｕｇｉｎｏｓａ）生长的影响。实验表明，在５００～５０００ｌｘ光强范围内，随光强增加，比增殖速率加大；在２２～３５℃区间内，比增殖速率随温度的升高而增加，且温度的影响大于光照；氮磷比（Ｎ／Ｐ）值在５～１０范围内，比增殖速率变化较大，Ｎ／Ｐ值为１４．５时，比增殖速率达最大值。滇池湖水的氮磷比值为１４．４左右，与实验值相接近。根据实验结果及限制因子的定义，总体上讲，滇池中磷是藻类生长的主要限制因子，控制滇池富营养化应以控制磷为主。     

4种不同培养基下铜绿微囊藻和四尾栅藻生长比较

选用4种蓝藻常用的培养基MA,M-11,BG-11和HGZ培养基,对铜绿微囊藻和四尾栅藻进行培养.结果表明2种藻对4种培养基都有较好的适应性,2种藻的μmax在MA中较大,在M-11,BG-11与HGZ中的接近,而在M-11和HGZ中的xmax较大.M-11培养基因成分简单,且2种藻在该培养基中对数生长期较长,最大比增长率μmax和最大现存量xmax都较大,为室内蓝藻、绿藻共培养小型、中型实验适宜的培养基.     

Physiological and biochemical responses of Microcystis aeruginosa to phosphite

Phosphorus (P) is a key biological element and limiting nutrient in aquatic environments. Phosphate (+5) is traditionally associated with the P nutrient supply. However, phosphite (+3) has recently generated a great deal of interest, because of the possibility that it is a P source based on recognition of its vital role in the original life of the early earth. This study investigated whether phosphite can be an alternative P source for Microcystis aeruginosa PCC 7806, one of the predominant bloom species in freshwater systems. The results indicated that M. aeruginosa could not utilize phosphite as a sole P-nutrient directly for cell growth at any concentration, but that phosphite could boost cell numbers and chlorophyll a (Chl-a) content as long as phosphate was provided simultaneously. Specifically, Chl-a production increased sharply when 5.44 mg P L⁻¹ phosphite was added to 0.54 mg P L⁻¹ phosphate medium. Analysis of the maximum yield of PSII indicated that phosphite may stimulate the photosynthesis process of cells in phosphate-phosphite medium. In addition, phosphite failed to support cell growth, even though it more readily permeated the cells in P-deficient medium than in P-sufficient medium. Alkaline phosphatase activity (APA) analysis indicated that, unlike organic P, phosphite inhibits the response of cells to deficient P status, especially under P-deprived conditions.     

聚铝及其加载粘土矿物高效絮凝沉降铜绿微囊藻的研究

考察了4种聚铝絮凝剂絮凝沉降铜绿微囊藻的效果，发现编号为HPACS02的聚铝絮凝剂除藻效果最好，并进一步研究得知HPACS02在pH7．5时絮凝除藻的效率最高。在采用HPACS02作为絮凝剂时，如果少量投加滑石、海泡石或高岭土等粘土矿物会对铜绿微囊藻的絮凝沉降产生增效作用，其中滑石的助凝效果最好。     

铜绿微囊藻、四尾栅藻和小环藻竞争实验培养基的选择

改变培养基的氮源形态和碳源浓度,研究铜绿微囊藻、小环藻和四尾栅藻的单藻增长行为,筛选适宜的培养基作为混藻竞争实验的共培养基。研究表明,铜绿微囊藻和四尾栅藻在氨氮培养基中的最大生物量K和最大比增长速率r均不及以硝态氮为氮源的培养基;添加高浓度HCO3-(NaHCO3 1.410 mmol/L)能够提高铜绿微囊藻和四尾栅藻藻细胞对氨氮的吸收能力;较低碳源浓度(NaCO3 0.0943 mmol/L)的培养基中,四尾栅藻的初始比增长速率及生物量远高于铜绿微囊藻,但其最大比增长速率r低于铜绿微囊藻,在实验的第10天左右铜绿微囊藻的生物量超过四尾栅藻;小环藻不能在较高浓度碳源(NaHCO3 1.504 mmol/L)下存活;铜绿微囊藻、四尾栅藻与小环藻均可在以氨氮(HA)或硝态氮(HN)为氮源的培养基中单独培养并达到实验所需生物量,因此,HN和HA可以作为实验室内这三种藻共培养适宜的培养基,为今后研究藻类种间资源竞争机制提供实验依据。     

Growth and phosphate uptake kinetics of Microcystis aeruginosa under various environmental conditions

Growth and uptake of exogenous phosphate by Microcystis aeruginosa in batch culture under different temperature, photoperiod, and turbulence were studied by the method of phosphate isotope tracer. Relatively high temperature, long photoperiod and strong turbulence increased the cell density of M. aeruginosa in these batch cultures. The initial rapid uptake of phosphate by M. aeruginosa was independent of the temperature, photoperiod, and turbulence. Similarly, maximum exogenous phosphate uptake was not related to these environmental factors. However, elevated temperature and turbulence shortened the time, required to obtain maximum P accumulation. The growth of M. aeruginosa could alleviate the phosphorous leakage. Total amounts of exogenous phosphate uptake to M. aeruginosa and the phosphorus leakage of M. aeruginosa were significantly influenced by the growth state of M. aeruginosa closely correlated with the environmental factors. The maximum volume of exogenous phosphate uptake to M. aeruginosa was 46% of added exogenous phosphate in water with 16 hours of photoperiod. Thus, total amounts of exogenous phosphate uptake to M. aeruginosa were more strongly affected by the photoperiod length than temperature and turbulence.     

不同质量浓度的磷对铜绿微囊藻生长及细胞内磷的影响

通过室内模拟的方法研究了在磷质量浓度不同的水体条件下,在铜绿微囊藻水华形成过程中微囊藻的增殖特征及细胞内磷、可溶性磷的变化特征.在模拟的太湖水体中,随着外源磷的增加,藻生长最终限制因素由磷限制(ρ(TP)≤0.045 mg/L)发展到光限制(ρ(TP)≥0.445 mg/L),而ρ(TP)=0.445 mg/L是微囊藻最适生长浓度;同时,微囊藻细胞内磷含量(QP)、水体可溶性磷(DTP)也随藻类生长而发生变化,在水体ρ(TP)＜0.445mg/L时,细胞内磷对微囊藻增殖有促进作用,而在ρ(TP)＞0.445 mg/L的水体中,磷对微囊藻增殖有抑制作用.     

铜绿微囊藻中性红染色研究

以铜绿微囊藻为材料,研究了中性红染色法在藻细胞活性检测方面的运用。对染色剂浓度、染色时间、细胞密度和细胞活性等条件进行了研究。结果显示,中性红浓度为1/5000,染色时间15min时,染色率可以达到98%以上。而常用的台盼蓝染色效果较差,只有50%左右。在藻细胞活性检测中,中性红比台盼蓝更准确和可靠。