Growth ofNostoc muscorum mutants in the presence of diuron (DCMU) and L-methionine-DL-sulfoximine

Summary Diuron (DCMU) is inhibitory to the photoautotrophic and photoheterotrophic growth of the N₂-fixing blue-green algaNostoc muscorum at concentrations of 1.0×10^–5 M and 2.0×10^–5 M, respectively. A mutant of this organism resistant to 5.0×10^–5 M DCMU under its photoheterotrophic growth conditions, with the ability to utilize DCMU as a carbon and nitrogen source for growth, and complete inability to grow photoautotrophically has been isolated. With the apparent defect in its photosynthetic ability, it is suggested that theDCMU ^r mutant lacks the step inhibited by 1.0×10^–5 M DCMU, and metabolizes DCMU by an existing enzyme system in the absence of such inhibition. That this enzyme may be glutamine synthetase (GS) is explained with the help of a L-methionine-DL-sulfoximine (MSO)-resistant mutant ofN. muscorum which is able to grow faster with 2.0×10^–5 DCMU and is known to contain an altered GS.Thanks are due to the Council of Scientific and Industrial Research, CSIR Complex, Govt. of India, New Delhi-110012, for appointing the author to the Scientists' Pool for undertaking researches on the physiological and genetic controls of nitrogen metabolism in blue-green algae, a part of which is presented in this literature.     

新疆维吾尔自治区绿藻初记

文中报道了我国新疆维吾尔自治区的淡水绿藻１４属３１种，其中大隐毛藻是中国首次记录。     

广州李坑垃圾场渗滤液中的藻类群落结构特征

对广州李坑生活垃圾填埋场渗滤液池的藻类群落结构进行为期1 a的调查。共发现藻类20种,分别归蓝藻门、绿藻门和硅藻门。其中,优势种类是蓝藻门中的席藻Phorm idium spp.。渗滤液中藻类数量和生物量的年平均值分别为13.47×108ind.L-1和144.70 m.gL-1。藻类生物量的年动态表现为冬春高、夏秋低,生物量最高的2月份达352.81 mg.L-1,最小的8月为20.50 m.gL-1。渗滤液中藻类群落的Shannon-W iever多样性指数的年变化类似于群落生物量的格局。渗滤液藻类生物量、群落多样性和优势种席藻的生物量与月平均温度、月雨量和NH+4-N呈负相关关系,而与COD、NO3--N、TP、O rtho-P呈正相关关系。     

藻类对土壤肥力的影响

通过完全蔽光和正常光照两个对照实验组，研究了光照、植物和藻类3个因子对土壤有机质、有效灰、微生物的影响，由极差分析知，混合藻对有效磷的变化和微生物数量的提高起主导作用。作者认为在80d内，混合藻类是藻类数量和有机质变化的主要原因；80d后，光照起主要的作用，在各处理组中，混合藻和光照的作用都强于植物的作用。土壤藻类对土壤肥力有明显的影响，与高等植物共同作用，对土壤肥力的提高效果明显。     

海洋绿藻77 K低温光谱特性的比较研究

在活体、叶绿体及类囊体膜水平上对8种海洋绿藻，包括2种管藻目绿藻剂松藻和假根羽藻、1种丝藻目绿藻软丝藻和5种石莼目绿藻缘管游苔、条浒苔、石莼、孔石莼及囊礁膜的低温荧光光谱进行了测定，并与高等植物菠菜做了比较．结果表明，几种海洋绿藻都缺少作为高等植物PSI主要表征的730nm长波荧光．其中管藻目绿藻刺松藻和假根羽藻的主发射峰位于685和695nm．说明这些藻类在PSl结构及能量传递方式上可能与高等植物不同．     

低钾对番红花光合作用的影响

低钾处理的番红花，叶片含钾量、叶绿素含量明显持续下降，光合作用及生长受抑制．叶片ＡＴＰ相对含量明显低于正常钾处理的番红花叶片．     

Experimental study of gold distribution in the algae-organic matter-fluid system

Conclusion Gold distribution and transformation in algae-organic matter-fluid system is very complicated. Gold is first concentrated in kerogen after algae died. With the increase of dissolved organic matter owing to the increase of temperature and pressure, part of gold simultaneously emigrates from kerogen to DOM. When DOM forms organic fluid and emigrates from the strata, gold is simultaneously carried away by organic fluid in acidic condition, but by water in alkali condition. When the auriferous fluid flows through carbonaceous strata, gold in fluid is unloaded by kerogen. Gold migration in the system, accompanied by the evolution of algae-organic matter-fluid, provides the basic information of biometallogenetic evolution of gold.     

海带热模拟实验的固体残余物研究及其石油地质意义

宏观底栖藻类作为海相烃源岩中重要的生油母质类型日益受到重视．通过对大型底栖褐藻海带的热模拟实验，利用傅立叶转换红外光谱、扫描电镜、漫反射光谱、反射率测定等分析和显微镜观察系统研究了海带的热演化规律，从有机质成熟度、残余物成分变化和实验样品的孔隙结构变化讨论了海带的石油地质意义．发现海带在较高的成熟度条件下依然具有较强的生烃能力，其孔隙发育规律对研究天然气的赋存和排出有着重要意义．     

硫酸苯酚法与焦糖化分光光度法相结合测定藻类水溶液中总糖浓度

藻在生长过程中分泌出的糖类物质的浓度比较低，并且随着藻的生长浓度的变化范围也比较大，通常单一的方法并不适应检测整个生长过程中的总糖浓度．本采用硫酸苯酚法与焦糖化分光光度法相结合的方法，测定含藻水溶液中总糖浓度的变化．从测定范围和准确性来看，均能满足测定的要求．