Resistance to Meloidogyne incognita in Ethiopian Coffea arabica accessions

Polyacrylamide gel electrophoresis (PAGE) was used to study the polymorphism of esterases in Allium cepa L. and A. fistulosum L. Two varieties of each species, an A. fistulosum × A. cepa interspecific F₁ hybrid, and (A. fistulosum × A. cepa) hybrid derivatives were analyzed for determination of banding patterns upon staining with α- and β-napthyl acetate substrates of esterase. Complex band patterns were observed. In total, 10 bands were detected between A. cepa and A. fistulosum — five inA. cepa, six in A. fistulosum with only one band common to both species. With the exception of one band unique to A. fistulosum which appeared only when stained with α-substrate, extracts of both A. cepa and A. fistulosum leaf tissue exhibited the same bands when stained with both α- and β-substrates. Bands stained with the different systems are distinguished by color: α-substrate always appeared black, while bands stained to β-substrate are always red. Esterase bands were assigned into 5 presumptive loci of four zones of activity with according to the migration distance of the bands from the front, color of each band upon staining with α- and β-substrates, and segregation observed in crosses and hybrid derivatives. Esterase enzymes detected in this study appear to be monomeric. Polymorphisms were identified between A. cepa and A. fistulosum by esterase banding patterns. Esterase enzymes provide an additional marker in monitoring introgression of foreign germplasm in interspecific onion breeding. This revised version was published online in August 2006 with corrections to the Cover Date.     

米粉凝胶强度与米粉品质指标的相关性研究

以市售米粉为研究对象,测定了其凝胶强度及质构参数,并分析了其凝胶强度与其蒸煮指标、质构指标以及感官评价之间的相关性。结果表明:米粉的凝胶强度与米粉的蒸煮损失、碘蓝值、熟断条率、硬度、弹性、咀嚼性以及感官指标中弹性、组织形态、糊汤性均存在显著相关性。在米粉的加工过程中,将米粉的凝胶强度控制在22.09~36.66 g·mm-2,大众接受程度会较高,在该范围内,米粉蒸煮损失<7%,熟断条率<2%,碘蓝值<0.300,弹性>0.89,米粉综合品质较好。因此,在米粉加工中,通过检测米粉的凝胶强度,并结合质构中硬度、黏性等指标的检测,即可反映米粉品质的好坏,无需再对米粉蒸煮损失、熟断条率等指标进行测定,有效地简化了米粉品质评价指标体系。     

利用盐溶蛋白PAGE电泳法检测玉米种子的研究

应用玉米盐溶蛋白PAGE电泳方法检测了10个玉米品种的纯度及其杂交种的真实性。通过品种间的盐溶蛋白谱带的对比,发现其中有2条蛋白带是各品种所共有的,而除这些共有的蛋白带以外,各品种还具有一些特异条带。根据每个品种特有的蛋白条带,建立其特征条带图谱,可应用于该品种的相关鉴定工作。     

芦荟提取液及其降解液制备凝胶的抑菌性研究

以芦荟提取液及其不同条件降解液制备的芦荟凝胶为研究对象,通过单因素试验和正交试验,研究不同添加剂对芦荟凝胶抑菌效果的影响,优化抑菌芦荟凝胶的添加剂配方。结果表明,制备的芦荟凝胶对大肠杆菌和金黄色葡萄球菌均具较好的抑菌效果,且不同降解液制备的凝胶抑菌性不同,说明降解条件影响了芦荟液中的抑菌活性物质,故表现出不同的抑菌效应。本试验优化结果表明,抑制大肠杆菌的芦荟凝胶添加剂最佳配方为:尿囊素浓度3.0 mg/m L,10%(V/V)三乙醇胺水溶液0.010 m L/m L,20%(W/V)Na OH水溶液0.015 m L/m L,卡松添加量为0.8μL/m L;抑制金黄色葡萄球菌的芦荟凝胶添加剂最佳配方为:尿囊素浓度3.6 mg/m L,10%(V/V)三乙醇胺水溶液0.010 m L/m L,20%(W/V)Na OH水溶液0.015 m L/m L,卡松添加量为1.0μL/m L。     

檫树过氧化物酶同工酶的初步研究

9年生檫树过氧化物酶同工酶基本酶谱有A_1,A_2,B,C_1,C_2,C_36条酶带;以树冠中部的幼叶分析最好;在树冠阳面与阴面采样,酶谱无差别;在4月10日至5月15日期间采样酶谱分离无影响;不同种源、不同家系的酶谱基本无差异。     

夏枯草凝胶的制备工艺研究

筛选夏枯草凝胶的最佳配方比。试验采用单因素法,以夏枯草凝胶剂的成型、均匀度、透明度和流动性为指标,考察不同基质的用量;采用正交试验筛选出最佳配方。结果表明夏枯草凝胶基质的最佳配比为卡波姆940添加量为0.4%,甘油添加量为10%,三乙醇胺添加量为0.7%。该制备工艺简单,稳定性良好,为其进一步开发提供理论依据。     

转基因棉花连续种植对土壤AM真菌群落结构的影响

为评价转基因棉花种植对土壤中AM真菌群落结构的影响,以转基因棉花013011（抗旱）、SGK321（抗虫）和非转基因棉花TH2（抗旱受体）、石远321（抗虫受体）为材料,研究不同生育期转基因棉花土壤中AM真菌的群落结构。采用PCR-DGGE技术对土壤中AM真菌的群落结构进行分析。结果发现：转基因棉花与非转基因棉花在花铃期和吐絮期土壤中AM真菌群落的最小相似度均大于0.6,这说明了转基因棉花的种植在花铃期和吐絮期均未对土壤中AM真菌的群落结构产生影响。另外转基因棉花和非转基因棉花的种植在花铃期和吐絮期均未对土壤AM真菌的丰富度（S）造成影响;土壤AM真菌香农-维纳指数（H）仅在吐絮期石远321显著低于SGK321,其余品种和时期均未出现显著性差异;土壤AM真菌的均匀度（E_H）仅在吐絮期发现TH2显著高于013011,其余品种和时期均未出现显著性差异。DGGE指纹图谱结果表明转基因棉花与非转基因棉花同一生长时期多为共有条带,且同一时期土壤AM真菌群落结构相似性较高,AM真菌的群落结构无明显变化。两个不同生育期优势属均为Glomus（球囊霉属）。研究表明：土壤AM真菌的群落结构变化只随着棉花生育期的不同会有短暂的变化,与是否为转基因棉花无显著性相关。     

旱作对稻米蒸煮品质的影响研究

选用以IR64为受体的抗旱基因聚合杂交后代的147个新品系为材料,以水作为对照,研究了旱作对稻米蒸煮品质的影响。结果表明:总体上旱作处理下抗旱新品系的胶稠度比水作处理下低,胶稠度越高的品系,旱作胶稠度降低越大;旱作处理下的碱消值比水作的高,碱消值越高的品系,旱作和水作处理下的差别越小;旱作处理下的直链淀粉含量比水作处理下低,随着直链淀粉含量的增加,旱作和水作的差别越大,但在AC较低时,旱作条件下比水作条件下稍高。在糊化温度和直链淀粉含量两性状上,旱作对改善品质是有利的,对胶稠度不利,不过胶稠度较高的品系中也有个别品系旱作处理的胶稠度比水作的相近或稍高,这些品系有望育成抗旱新品种作为旱作品种推广。     

库姆克尔原油胶质、沥青质组分对其流变性的影响

利用氧化铝吸附色谱分离库姆克尔原油中的胶质、沥青质,然后利用碱性氧化铝和酸性氧化铝吸附色谱分离胶质、沥青质中的酸性组分、碱性组分和中性组分。利用傅里叶变换红外光谱和核磁共振波谱研究了胶质沥青质分离组分的有机官能团,结果表明：中性组分的极性官能团含量很少,酸性组分的极性官能团含量较多,碱性组分的极性官能团含量最多;中性组分为烷烃物质,碱性组分含有氮、氧杂原子,表现为有机胺、有机醚,并含有酯基,酸性组分的特征官能团为羧酸,亦含有氮、氧等杂原子。将分离组分按1%的质量分数添加到原油或加剂原油中,研究其对原油或加剂原油流变性的影响,结果表明：对库姆克尔原油粘度产生不利影响的是胶质沥青质中的酸性组分。添加可以与酸性组分相互作用的降凝剂,可以明显降低库姆克尔原油的粘度,抑制酸性组分对原油流变性的恶化作用。     

Impact of monoculture of poplar on rhizosphere microbial communities over time

To date, research on the adverse effects of continuous cropping has focused on field crops; forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution of microbial community in the rhizosphere of forest plantations, in particular, has rarely been examined. In this study, changes in the size, composition, and structure of bacterial and fungal communities in the rhizosphere of different generations of poplar (Populus deltoides) plantations were studied using real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis and compared with the composition of the microbial community in a bare land (control) adjacent to the plantation sites through sequencing analysis and by constructing phylogenetic trees. The numbers of bacteria and fungi increased significantly with successive poplar generations, although the increases in the two groups were not parallel. When compared with the control, the bacterial community increased greatly in the second generation, and the most significant increase occurred in the third generation. In contrast, the most significant increase in the fungal community occurred in the first generation, and the increase in the third generation was insignificant. In terms of community composition, the first generation showed little change in either community; however, the second generation showed remarkable changes in the bacterial community, and the third in the fungal community. The numbers of Gammaproteobacteria, Alphaproteobacteria, and Actinobacteria increased by 10.92%, 7.38%, and 5.46%, respectively, whereas those of Acidobacteria decreased by 18.38% in the second generation. These changes in the number and composition of microbial communities in the rhizosphere could be one of the reasons for the decline in yield and quality associated with long-term monoculture.