普通念珠藻多糖复合物对植物生长的促进作用

以普通念珠藻为原料,用水作提取剂,提取得到普通念珠藻多糖复合物N(P)。以水稻、番茄、白菜上海青、吊钟花、墨兰、柳枝为材料,研究NP对试验对象生长的影响。结果表明,NP能促进盆栽水稻的生长和分蘖;使盆栽番茄株高增高,株茎增粗,鲜重、干重增加;使盆栽上海青白菜鲜重、干重增加;促进盆栽吊钟花的株高增高,花芽数增多;使盆栽墨兰分蘖率提高;促进柳枝根系生长,新芽数增多,且芽长增长;促进大田番茄株高增高、株茎增粗,增加成熟果总重。     

Mechanical damage of roots provides enhanced colonization of the wheat endorhizosphere by the dinitrogen-fixing cyanobacterium Nostoc sp. strain 2S9B

 When wheat (Triticum aestivum L.) seedlings are co-cultivated with Nostoc sp. strain 2S9B in hydroponics, the cyanobacterium colonizes the endorhizosphere at low frequency. Mild sonication of the roots dramatically increased the number of cyanobacteria within the root tissue. The cyanobacteria penetrated the roots in the form of motile filaments (hormogonia), and once inside, they divided and transformed into aseriate packages, which showed nitrogenase activity. Cyanobacteria were found in the intercellular spaces as well as inside the epidermal and cortex cells. By prolonging the sonication time the number of cyanobacterial packages inside the roots increased. However, after reaching a certain abundance the total cyanobacterial biomass within the roots did not change regardless of the sonication time. Besides sonication, other methods of root surface damage also brought about enhanced internal root colonization. Sonication of roots proved to be an efficient way of amplifying the internal root colonization by cyanobacteria and can be suggested as a method for creating a model system in non-legume plant-microbe studies. Received: 12 August 1999     

2种常用除草剂对1株稻田固氮念珠藻的毒性效应研究

[目的]评价除草剂对固氮蓝藻的毒性。[方法]以稻田固氮蓝藻念珠藻FACHB85为供试藻种,研究除草剂莠去津和丁草胺的毒性效应。[结果]莠去津对FACHB85的毒性存在明显的剂量-效应关系,0.8 mg/L莠去津可明显抑制藻体生长（藻体比生长速率仅为对照的25%,且藻体断裂严重）;在试验期（15 d）内莠去津对FACHB85的EC50值为0.035～0.080 mg/L,12 d后其EC50值达到稳定且高于前5 d的EC50值;随莠去津浓度增加,FACHB85的异形胞频率逐渐减小。在试验浓度（0～640 mg/L）范围内,丁草胺对FACHB85的生长基本无影响,且不同浓度丁草胺处理FACHB85的异形胞频率无显著差异。[结论]莠去津对FACHB85具有很强的毒性,而丁草胺对FACHB85的毒性较小。     

普通念珠藻(Nostoc commune Vauch.)藻蓝蛋白的提取

[目的]为普通念珠藻藻蓝蛋白的提取及开发提供试验及理论基础。[方法]以普通念珠藻为材料,比较藻体及细胞的破碎方法、提取液类型及饱和硫酸铵浓度对藻蓝蛋白提取的影响。[结果]结果表明:利用发酵法破碎藻体和细胞,0.05 mol/L的KP缓冲液(pH值7.2)作为提取液,经过30%~50%饱和硫酸铵盐析和DEAE-Toyopeal 650 S离子交换柱层析后,藻蓝蛋白纯度达2.51,最大紫外-可见吸收峰位于616 nm。[结论]普通念珠藻藻蓝蛋白分离提取较为理想的程序为:藻粉→0.05 mol/L KP缓冲液(pH值7.2)浸泡→发酵法破碎细胞→35%~50%饱和硫酸铵盐析→DEAE-Toyopeal 650 S柱层析→较纯的藻蓝蛋白。     

无机盐诱导两种蓝藻异形胞的效果比较

蓝藻异型胞与生物固氮密切相关,同时也是蓝藻产氢的主要场所。采用17种无机盐,对两种蓝藻的异型胞分化进行诱导,实验结果表明：低渗水平浓度（0．05mol／L）的NaCl,MgCl2和MgSO4,既促进水华鱼腥藻（Anabaena flos—aquae）生长,又促进其异形胞的分化。其中,MgCl2对两者的促进作用最明显,分别比对照提高了1．5倍和1．2倍。17种无机盐中,只有MgSO4对念珠藻（Nostoc sp．）的生长和异形胞的分化都有促进作用,分别比对照提高了50％和56％。对两种藻的比较结果发现,无机盐对水华鱼腥藻的诱导作用明显大于念珠藻。     

青海高原地木耳中微量元素的化学计量学研究

[目的]对青海高原地木耳中Cu、Zn、Fe、Mn、Co、Se等微量元素进行综合评价。[方法]通过主成分分析、因子分析和聚类分析研究了青海高原地木耳中的微量元素。[结果]Fe与Co、Se相关极显著,Mn与Zn相关极显著。Fe的第1主成分值最大,说明青海高原地木耳中微量元素Fe的影响最大。海西州地木耳中微量元素含量最高,其次为海北州、海南州、黄南州、西宁市。海西州和海北州地区地木耳中微量元素较丰富,且海西州地木耳中微量元素的含量远高于西宁市。第1公共因子F1在指标Fe、Co、Se上有较大的载荷,第2公共因子F2在指标Cu、Zn、Mn上有较大的载荷。[结论]该研究为大规模开发青海高原地木耳资源提供了科学依据。     

葛仙米表层结构的扫描电子显微镜观察

[目的]探寻观察葛仙米表层结构的新方法。[方法]利用扫描电镜技术,对野生葛仙米与室内培育葛仙米表皮超微结构进行观察。[结果]野生与室内培育葛仙米表皮都呈网状交错排列的纤丝胶质混合结构特征,不同的是室内规模培育葛仙米群体表皮外层有藻丝分布,而野生葛仙米表皮外层未见藻丝分布。10μm以下的葛仙米群体表皮质感厚实,呈现出很多皱纹,扭曲。[结论]扫描电子显微镜技术是研究葛仙米群体发育的有效工具,值得推广。     

藻类植物减少大棚土壤及蔬菜中残留敌敌畏的效果初报

大棚栽培多数是长年连作,密闭条件好,土壤中农药的残留问题就更加明显。实验证明藻类植物地木耳可在大棚中生存。通过在大棚种植的蔬菜旁种植地木耳,可使大棚土壤和蔬菜中农药含量降低,降低幅度约为59%。     

Influence of the photosynthesis-inhibiting herbicides goltix and sencor on growth and nitrogenase activity of Anabaena cylindrica and Nostoc muscorum

Summary The influence of the photosynthesis-inhibiting herbicides Goltix and Sencor on growth and nitrogenase activity of Anabaena cylindrica and Nostoc muscorum was studied. The cyanobacteria were grown under N₂-fixing photoautotrophic conditions. A. cylindrica was entirely inhibited even in the presence of low field concentrations (Sencor 10 ppm, Goltix 50 ppm). In contrast, Goltix (50 ppm and 100 ppm) and Sencor (10 ppm, 20 ppm, 50 ppm and 100 ppm) did not exert an inhibitory influence on growth and nitrogenase activity of N. muscorum. In the presence of normal field rates of the studied herbicides increased light intensities during incubation had no detrimental effect on N. muscorum. Only at 20 W/m² light intensity did the higher concentrations of Sencor (50 ppm and 100 ppm) cause partial inhibition for the first 10–12 days, which was compensated during subsequent incubation. The delayed inhibitory effects caused by higher concentrations of Goltix (200 ppm and 500 ppm) are supposed to be due to degradation product(s). In the natural environment other species of cyanobacteria may occur which are able to tolerate photosynthesis-inhibiting herbicides.     

乙酰胺对念珠藻Nostoc 106生长周期的影响

研究了不同浓度的乙酰胺对念珠藻106(Nostoc sp.106)在对数期、稳定期和生长末期的影响。研究结果表明加入一定浓度的乙酰胺对蓝藻生长有一定的刺激作用。测定叶绿素a、藻胆蛋白含量、SOD含量、ATP含量等生长代谢指标,表明加入浓度为1、2和5 mg/m L的乙酰胺不同程度地延缓了念珠藻Nostoc sp.106的衰亡,浓度5 mg/m L的乙酰胺增加了念珠藻Nostoc sp.106在生长对数期的时间。