Assessment of the effects of the photosynthesis-inhibiting herbicides Diuron,DCMU, metamitron and metribuzin on growth and nitrogenase activity of Nostoc muscorum and a new cyanobacterial isolate,strain G4

Summary The influence of the photosynthesis-inhibiting herbicides Diuron, DCMU, metamitron, and metribuzin on growth and nitrogenase activity of Nostoc muscorum and a new cyanobacterial isolate, strain G4, was studied. The experiments were performed under N₂-fixing photoautotrophic conditions. Both cyanobacteria showed a high degree of tolerance towards the herbicides tested. In the presence of metamitron (35, 70, and 140 ppm) and metribuzin (7, 14, 35, and 70 ppm) strain G4 proliferated as well as the control culture. Metamitron and metribuzin had no influence on the nitrogenase synthesis of strain G4 and N. muscorum. When treated with 1 M DCMU, strain G4 and N. muscorum showed partial inhibition for the first few days, but entirely recovered during succeeding incubation. In the presence of 10 ppm Diuron, N. muscorum and strain G4, compared to the control, showed 30% and 80% nitrogenase activity, respectively.     

地木耳实用价值的研究

分别从食用与医疗保健、工业生产、环境监测和农业生产等方面,对地木耳的实用价值进行了简单综述,分析了其在现代生活中的具体作用与潜在利用价值,并对其发展前景进行了讨论。     

地木耳提取液对生菜种子萌发及幼苗生长的影响

采用室内模拟培养法,研究地木耳提取液对生菜种子萌发和幼苗生长的影响。结果表明,地木耳提取液对生菜种子的发芽率无影响,但对幼苗的生长发育有明显的促进作用;幼苗根长、株高、侧根数和叶绿素含量与对照相比,均有显著增加,尤以0.2 mg/mL的地木耳提取液效果最好,但不同生理指标显示的最适浓度有差异。生菜作为食叶类蔬菜,以叶绿素含量作为指示性生理指标更为适宜,因此,地木耳提取液的最佳质量浓度为0.05 mg/mL。     

神奇野菜——葛仙米

介绍了葛仙米的营养成份和保健功能，并分析了葛仙米的价值和开发前景。葛仙米含氨基酸17种，氨基酸总量为93.7mg/100ml，总蛋白质为52%，维生素C为521mg/100ml，以及14种人体必需的微量元素和维生素B等成份。     

发状念珠藻多糖的提取及其对农作物种子发芽率的影响

[目的]为发状念珠藻多糖的提取、开发及生物学活性研究提供试验及理论基础。[方法]以发状念珠藻为材料,用石油醚脱脂脱色素,80%的乙醇去可溶性小分子糖类,用水作提取剂,98℃下提取3次,每次3 h,合并提取液后减压浓缩,三氯乙酸脱蛋白,SephadexG-50层析纯化,醇析后冷冻干燥,进行红外光谱测定和种子发芽试验。[结果]结果表明,发状念珠藻多糖得率为15.8%~19.7%,红外光谱的特征吸收峰明显,是一种含氨基和β-糖苷键,不含硫酸基的多糖。当多糖浓度为1.0 mg/L时油菜种子、小麦种子、水稻种子和胡麻种子的发芽率分别比对照组增加14.29%、12.79%、4.40%和15.48%,而多糖浓度为2.0 mg/L时白菜和玉米种子的发芽率分别比对照组增加11.24%和22.50%。     

Complementary UV-Absorption of Mycosporine-like Amino Acids and Scytonemin is Responsible for the UV-Insensitivity of Photosynthesis in Nostoc flagelliforme

Mycosporine-like amino acids (MAAs) and scytonemin are UV-screening compounds that have presumably appeared early in the history of life and are widespread in cyanobacteria. Natural colonies of the UV-insensitive Nostoc flagelliforme were found to be especially rich in MAAs (32.1 mg g DW⁻¹), concentrated in the glycan sheath together with scytonemin. MAAs are present in the form of oligosaccharide-linked molecules. Photosystem II activity, measured using PAM fluorescence and oxygen evolution, was used as a most sensitive physiological parameter to analyse the effectiveness of UV-protection. Laboratory experiments were performed under controlled conditions with a simulated solar radiation specifically deprived of UV-wavebands with cut-off filters (295, 305, 320, 345 and 395 nm). The UV-insensitivity of N. flagelliforme was found to cover the whole UV-A (315–400 nm) and UV-B (280–320 nm) range and is almost certainly due to the complementary UV-absorption of MAAs and scytonemin. The experimental approach used is proposed to be suitable for the comparison of the UV-protection ability in organisms that differ in their complement of UV-sunscreen compounds. Furthermore, this study performed with a genuinely terrestrial organism points to the relevance of marine photoprotective compounds for life on Earth, especially for the colonization of terrestrial environments.     

地皮菜中多糖的抑菌特性研究

用超声波细胞破碎机对野生地皮菜破碎后,利用石油醚脱脂及乙醇提取其中的多糖并纯化,利用滤纸片法测定其含量,并检测提取多糖对一些致病菌的抑菌特性。结果表明,地皮菜中多糖含量可达8.5%,对大肠杆菌、炭疽杆菌及金黄色葡萄球菌有不同程度的抑制作用,且抑菌作用随着多糖浓度的增大而增强。     

葛仙米表层结构的扫描电子显微镜观察

近年来由于全球气候变化和土壤生态环境改变等原因导致葛仙米产量大大降低。现已有葛仙米室内规模批量培育生产,但室内培养的葛仙米在生长过程中容易发生破裂,且其群体韧性要比野生葛仙米群体弱、其所含蛋白质与维生素含量均比野生葛仙米低。因此,笔者运用扫描电子显微镜（SEM）观察野生葛仙米和室内规模葛仙米表层结构,了解两者的区别,同时为葛仙米表层结构观察找寻新方法。     

发菜人工培养的研究进展

发菜是一种固氮陆生蓝藻,我国主要分布于西北干旱半干旱荒漠草原地带,具有重要的经济和生态价值,围绕发菜资源基础研究和保护开发的应用研究已广泛开展.对近年来发菜人工培养的研究,从培养方式、培养基类型、环境因子、植物生长物质等方面进行了综述,并提出了存在的问题和今后研究的方向.     

发菜生长地的土壤因子分析

本文观察并分析了发菜生长地的土壤剖面,对生长发菜和不生长发菜的表层土壤作了理化测试和分析:发菜生长地的土壤有机质含量为1.040％左右,是不生长发菜的40～50倍;全氮量是0.001％,比不生长发菜的低10倍;全磷量是0.078％,是不生长发菜的10倍;pH为7.5～8.4;发菜生物量与土壤全氮不相关而与全磷和有机质相关。