激光预处理种子提高大豆幼苗抗冷害的机理探讨

从能量转移、膜系统和自由基3个方面探讨了激光预处理大豆种子提高其幼苗抗寒性的机理.研究结果表明,激光(He-Ne)预处理大豆种子不但明显地提高大豆种子三磷酸腺苷(ATP)的含量,而且提高其幼苗(子叶期到第一真叶期)的抗低温胁迫的能力.处理组幼苗在3℃～5℃低温胁迫下比对照组有较高的过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)和淀粉酶(AML)的活性及可溶性蛋白质含量.同时预处理还降低了幼苗子叶中超氧阴离子(O2-)含量、丙二醛(MDA)的积累量及电解质外渗率.     

遗传重组教学探讨

遗传重组是普通遗传学的重点内容之一.本文总结了遗传学教学中遗传重组特别是三点测验的教学体会,并简单介绍了一些有关进展.     

不同环境中胞外多糖产生菌的初步研究

从不同的环境中采集样品,采用LB平板稀释法和苯胺蓝法分析样品中胞外多糖产生菌的丰度并分离胞外多糖产生菌;以发酵产糖量分析进行复筛,对产糖量较高的菌株进行常规生理生化分析和16SrDNA序列分析.结果表明:不同环境中胞外多糖产生菌的数量和类别有较大差异,其中活性污泥中胞外多糖产生菌数量最多;复筛得到89个菌株,选择其中8个产糖量较高的菌株进行生理生化实验和16SrDNA序列分析,结果显示:4个菌株属于芽孢杆菌属,另外4个可能属于新的细菌菌株.     

Genotoxic Effects of Superconducting Static Magnetic Fields （SMFs） on Wheat （Triticum aestivum） Pollen Mother Cells （PMCs）

The effects of superconducting static magnetic fields （SMFs） on the pollen mother cells （PMCs） of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities （0, 1, 3, 5 and 7 Tesla） for 5 h or different durations （1, 3 and 5 h） at a magnetic flux density of 7 Tesla. The seeds were germinated at 23℃ after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus （MN）, chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity （below 5 Tesla） showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T.     

香菇多糖的酶法提取

利用果胶酶、纤维素酶和漆酶对香菇进行酶解,固定料水比(1∶15)和反应温度(40℃),以酶解后多糖提取率为指标,考察不同浓度的3种酶对香菇多糖提取的影响。在单因素试验的基础上,采用响应面法建立香菇多糖酶法提取的二次多项数学模型,并验证了该模型的有效性;探讨了果胶酶、纤维素酶、漆酶3个因子的交互作用及其最佳水平。响应面分析结果表明:果胶酶、纤维素酶、漆酶显著影响香菇多糖的提取效果,在果胶酶浓度为7.11%,纤维素酶浓度为6.82%,漆酶浓度为3.69%的优化条件下,香菇多糖的提取率达到37.07%。     

静态强磁场(SMFs)对小麦花粉母细胞(PMCs)的遗传毒性研究

研究了静态强磁场(Static magnetic fields,SMFs)对小麦花粉母细胞的影响,以评价环境中这种非电离辐射可能的遗传毒性.将小麦种子暴露于不同磁场强度(1、3、5、7T)/5h及进行不同时间(1、3、5h)/7T的处理,取其幼穗进行常规制片.以微核、染色体桥、落后染色体、断片、非四极分裂等的频率作为DNA损伤的指标来评价SMFs的遗传毒性作用.结果表明,5T以下剂量,暴露组与对照组之间在畸变频率上无统计学意义上的差别,5T场强下染色体桥、7T场强下落后染色体、三极分离、微核的频率则有显著的提高.剂量-效应呈现出剂量依赖的非线性关系,表明5T以上静态强磁场可能对生物体具有某种遗传损伤效应.