固氮根瘤菌与海南主栽菜用大豆的共生匹配性和促生效应

为筛选与海南主栽菜用大豆品种“六四”、“翠绿宝”和“铁豆”匹配性高且固氮能力强的大豆根瘤菌,本研究选择了8株分离自不同生态区的根瘤菌,采用低氮蛭石基质栽培方法进行培养和筛选,测定了茎叶干重、叶片SPAD值、根干重、根瘤干重、根瘤数量等指标,并对其进行结构方程模型分析和相关性分析,以评价不同根瘤菌对菜用大豆生长的影响。结果表明:(1)不同菜用大豆品种接种不同根瘤菌促生效果差异显著,接种CCBAU 25435对菜用大豆茎叶干重、叶片SAPD值等生长指标的提高效果显著,较不接种根瘤菌增加80%和112%,与国际上广泛接种的高效固氮根瘤菌USDA 110相比无明显差异甚至略优;(2)叶片SPAD值、根干重、瘤干重对茎叶干重的形成有显著的正直接效应,其中叶片SPAD值的影响权重最高,根瘤数则通过前三者间接促进了茎叶干重的形成;(3)中效和高效结瘤固氮根瘤菌的根瘤数和瘤干重显著高于无效菌,而高效菌的单位瘤干重显著低于中效菌。本研究筛选得到的高效固氮根瘤菌为海南地区根瘤菌剂的开发应用提供了优质根瘤菌资源。

Intraductal neoplasm of the intrahepatic bile duct: Clinicopathological study of 24 cases

AIM: To investigate the clinicopathological features of intraductal neoplasm of the intrahepatic bile duct (INihB). METHODS: Clinicopathological features of 24 cases of INihB, which were previously diagnosed as biliary papillomatosis or intraductal growth of intrahepatic biliary neoplasm, were reviewed. Mucin immunohistochemistry was performed for mucin (MUC)1, MUC2, MUC5AC and MUC6. Ki-67, P53 and β-catenin immunoreactivity were also examined. We categorized each tumor as adenoma (low grade), borderline (intermediate grade), and malignant (carcinoma in situ , high grade including tumors with microinvasion). RESULTS: Among 24 cases of INihB, we identified 24 tumors. Twenty of 24 tumors (83%) were composed of a papillary structure; the same feature observed in intraductal papillary neoplasm of the bile duct (IPNB). In contrast, the remaining four tumors (17%) showed both tubular and papillary structures. In three of the four tumors (75%), macroscopic mucin secretion was limited but microscopic intracellular mucin was evident. Histologically, 16 tumors (67%) were malignant, three (12%) were borderline, and five (21%) were adenoma. Microinvasion was found in four cases (17%). Immunohistochemical analysis revealed that MUC1 was not expressed in the borderline/adenoma group but was expressed only in malignant lesions (P = 0.0095). Ki-67 labeling index (LI) was significantly higher in the malignant group than in the borderline/adenoma group (22.2 ± 15.5 vs 7.5 ± 6.3, P < 0.01). In the 16 malignant cases, expression of MUC5AC showed borderline significant association with high Ki-67 LI (P = 0.0622). Nuclear expression of β-catenin was observed in two (8%) of the 24 tumors, and these two tumors also showed MUC1 expression. P53 was negative in all tumors. CONCLUSION: Some cases of INihB have a tubular structure, and are subcategorized as IPNB with tubular structure. MUC1 expression in INihB correlates positively with degree of malignancy.

Dry Matter Partitioning, Nodulation and Seed Traits of Medium and Late Maturing Soybean Varieties as Affected by Planting Pattern and Plant Density

An experiment was conducted on Fluvisols of Awassa for two consecutive years （2005-2006） to determine effects of planting pattern and plant density on dry matter accumulation, nodulation, protein and oil content in early and late maturing soybean varieties. Results indicated that Awassa-95 variety produced significantly higher （P 〈 0.05） number of nodules/plant （NDN）, nodule dry matter （NDM） and leaf dry matter （LDM at R2 （mid flowering） stage of soybean growth than that of variety Belessa-95）. Similarly, variety Awassa-95 （45%） produced significantly higher protein content than variety Belessa-95 （40%）. However, variety Belessa-95 accumulated significantly higher （P 〈 0.01） dry matter in straw, grain and total biomass at R7 （physiological maturity） stage of soybean growth than variety Awassa-95. Similarly, oil content of variety Belessa-95 （18.1%） was significantly （P 〈 0.05） higher than that of variety Awassa-95 （15.9%）. Equidistant rows produced significantly higher （P 〈 0.05） NDM than either rectangular or paired rows. Moreover, soybean plants grown in both rectangular and equidistant rows produced significantly higher （P 〈 0.01） straw dry matter than those grown in paired rows; but, grain dry matter/plant （GDM） was significantly higher （P 〈 0.01） paired and rectangular rows compared to equidistant rows. Plant density also affected the per plant GDM production as it was significantly higher （P 〈 0.01） in 20 and 30 plants/m2 than higher plant densities （40 and 50 plants/m2）. However, dry matter and yield components had strong negative association with protein content. In fact, strong positive correlation （R 〉 0.600） occurred between grain yield and its components with dry matter components at R2 （stem dry matter （SDM）, leaf dry matter （LDM） and stem ＋ nodule ＋ leaf dry matter together known as TDM） and straw dry matter at R7 in both varieties. This study depicted that soybean plants that produce higher dry matter components at R2 would probably produce more straw dry matter, greater grain yield components and higher grain yield dry matter at later stages.