A geographical approach to identify phosphorus-efficient genotypes among landraces and wild ancestors of common bean

Cultivars of common bean (Phaseolus vulgaris L.) capable of yielding well at low levels of native or added phosphorus (P) are highly desirable in many tropical production systems. The objective of the present study was to identify geographical regions which might be sources of such genotypes. A total of 364 landraces, cultivars and wild genotypes, drawn from a broad geographic range, were divided on the basis of growth habit into four field trials, each comprising two levels of P, stressed and unstressed, on an infertile Andosol in Popayan, Colombia. The regression relationship between grain yield per plant in the presence and in the absence of stress was determined, and each genotype's deviation from this relationship was used as a measure of P-efficiency. There was highly significant variation in efficiency among genotypes in all growth habits, and in climbing beans there were consistent regional differences, superior genotypes being identified with greater frequency among those from Bolivia, West Mexico and South Mexico-West Guatemala. The latter region was promising for prostrate bush genotypes also. Wild beans in general performed relatively poorly; it appears that P-efficiency traits in P. vulgaris have been acquired during or after domestication. These results confirm that genetic differences in P-efficiency exist among common bean genotypes and suggest that these are related to geographic origin. Furthermore, the use of a representative sample of germplasm can help to identify segments of the gene bank that are especially promising as sources of desirable traits. This revised version was published online in July 2006 with corrections to the Cover Date.     

Analysis of morphological variation in wild beet (Beta vulgaris L.) from Sicily

Summary In this paper the variation pattern of the Sicilian Beta germplasm collection is analysed. Accessions from Sicily were grown under controlled conditions and were evaluated morphometrically. Geographical distribution patterns of morphological characters are identified and the putative classification of the collection into coastal and inland populations is reassessed. Between adjacent populations significant variation was found for Petiole length, Leaf length, Leaf width and Biomass, however no one variable unambiguously reflected a geographical pattern. Overall differences between coastal and inland populations were small. Petiole length and rate of generative development were found to be important for distinguishing between these groups. Interferences are drawn on how the collection from Sicily could be rationalized to avoid excessive duplication.     

新杀虫植物砂地柏研究进展

对新发现的一种杀虫植物砂地柏（Ｓａｂｉｎａ　ｖｕｌｇａｒｉｓ Ａｎｔ．）的资源、化学、药理学及杀虫活性等方面研究情况及进展作了论述．通过对砂地柏药理学及杀虫活性等方面的研究结果的总结和分析，为害虫防治方面的基础理论和实际应用研究提供了依据。     

集合环境梯度对森林生物多样性的影响

通过对不同环境梯度上的森林群落内植物和昆虫类群生物多样性的研究，发现森林各功能类群的多样性与集合环境梯度间的相关关系不很明显，但可以看出它们都随环境梯度的升高而呈上升的趋势，Ｂｅｔａ多样性与环境梯度相关紧密，呈直线上升，从植物类群物种的βｚ与昆虫类群物种的βｋ对集合环境梯度变化的反应来看，βｋ明显落后于βｚ。     

新疆圆柏黄酮类成分的研究

采用硅胶、Sephadex LH-20柱等色谱手段,对新疆圆柏叶的黄酮类成分进行了研究,从中分离鉴定了9个黄酮类化合物:柏木双黄酮(Ⅰ)、柏木双黄酮4',4'-二甲醚(Ⅱ)、穗花杉双黄酮(Ⅲ)、罗汉松双黄酮A(Ⅳ)、儿茶素(Ⅴ)、槲皮素(Ⅵ)、异高黄芩素7-O-β-D-木糖苷(Ⅶ)、杨梅素3-O-β-D-葡萄糖苷(Ⅷ)和芦丁(Ⅸ).其中化合物Ⅰ、Ⅱ、Ⅴ、Ⅶ、Ⅷ和Ⅸ为首次从该植物中分离得到,化合物Ⅷ和Ⅸ为首次从该属植物中分离得到.二苯代苦味肼基自由基(DPPH·)清除活性测试结果表明,化合物Ⅴ和Ⅵ的抗氧化活性较高,与阳性对照品抗坏血酸的接近;黄酮苷类化合物Ⅷ、Ⅷ和Ⅸ次之,而双黄酮类化合物Ⅰ、Ⅱ、Ⅲ和Ⅳ活性较差.     

云南花生丛枝植原体secY基因序列分析及结构预测

目的 确定采自元谋地区自然表现丛枝病的小驳骨(Gendarussa vulgaris Nees)植株是否感染植原体。 方法 通过利用植原体16S组和亚组通用或半通用特异性引物分别对植原体16S rRNA、rp和secY基因序列进行PCR扩增、克隆及测序分析;此外还对secY蛋白的蛋白特性及其结构进行了分析和预测。 结果 本研究获得了基因片段长度分别为1 248 bp的16S rRNA基因(nested PCR)、1 171 bp 的rp基因和1 425 bp的secY基因。基于rp和secY基因核苷酸序列的同源性比对及构建的进化树推断的植原体遗传分化关系几乎与16S rRNA基因的推断相一致,均与植原体16S rII-A亚组各株系的遗传进化关系最为接近,但rp和secY基因序列比16S rRNA基因序列能够呈现出更大的遗传变异程度;此外,对secY蛋白进行了生物信息学分析和初步探讨,发现它具有10个明显且分布相对均匀的跨膜螺旋区域,无信号肽。 结论 小驳骨丛枝病(Gendarussa vulgaris witches’-broom phytoplasma,GvWB-YNym)是由植原体侵染而发生,该植原体株系被划分到16S rII-A亚组,相关的候选种为Candidatus Phytoplasma aurantifolia;secY蛋白生物信息参数的分析表明：secY蛋白在感病小驳骨植株中以疏水性稳定跨膜蛋白的形式存在,含10个明显的疏水跨膜区域,该蛋白不存在信号肽。     

用壳聚糖絮凝法采收小球藻及上清液再利用的研究

针对工业化培养小球藻Chlorella vulgaris时存在的采收困难以及后续上清液的循环利用问题,设计了培养小球藻的新型循环模式,具体操作步骤为：用气升式反应器培养小球藻→加入壳聚糖絮凝→过滤藻体得上清液→在上清液中补加营养成分→加入气升式反应器中再用于培养小球藻。结果表明：在5次小球藻循环培养中,后4次循环培养藻体的生长速率和收获期浓度均比第1次培养的稍高;用壳聚糖作为絮凝剂时其絮凝效果较好,且未产生絮凝抑制性;每次循环时在上清液中定量补加营养成分,NO3--N、PO34--P含量变化均在无抑制积累的范围内。说明利用壳聚糖作为絮凝剂采收小球藻的效果及利用上清液循环培养小球藻的效果都比较理想。     

铜绿微囊藻和小球藻室内竞争实验研究

对铜绿微囊藻和小球藻进行藻类竞争实验,并通过模拟计算,分别得到铜绿微囊藻和小球藻纯培养和竞争条件下的生长模式,并计算了2种藻之间的相互竞争抑制强度。纯培养时铜绿微囊藻和小球藻的增长速率r分别为0.451/d和0.419/d,最大环境容量K分别为1414×104个/mL和812×104个/mL;混合培养时铜绿微囊藻对小球藻的种间竞争强度为1.44,小球藻对铜绿微囊藻的种间竞争强度为0.9。     

Influence of Phytohemagglutinin on the Agronomic Performance of Beans (Phaseolus vulgaris L.)

The abundant lectin phytohemagglutinin (10 % of total seed protein) does not contain sulfur amino acids and, being a potent antimetabolite, it is responsible for the lowering of the nutritional value of bean seeds. The aim of the present work was to improve the dry bean cultivar ‘Taylor's Horticultural’ (Asgrow), by genetically introducing the lectin null (lec/lec) character from two null genotypes: ‘Pinto UI 111’ and ‘Heidi’. Thirty-seven BC²F₃ and fourteen BC₆F₅ inbred lines were evaluated in agronomical trials. Analysis of Variance (ANOVA) showed significant differences among BC₂F₃ breedings lines for all traits under evaluation. Comparison of the LedLee genotypes versus lec/lec did not show statistically significant differences in the means for the following traits: yield, yield components and percentage of protein in the seed. Fourteen BC6F5 lines, compared together with their recurrent parent ‘Taylor's Horticultural’, showed significant differences among genotypes for 1000 seed weight, protein percentage on dry matter and ash percentage. No significant differences were observed for grain yield. The data indicate that lectin removal did not have a detrimental effect on the traits evaluated.     

The concept of habitat specificity revisited

Habitat specificity indices reflect richness (α) and/or distinctiveness (β) components of diversity. The latter may be defined by α and γ (landscape) diversity in two alternative ways: multiplicatively () and additively (). We demonstrate that the original habitat specificity concept of Wagner and Edwards (Landscape Ecol 16:121–131, 2001) consists of three independent components: core habitat specificity (uniqueness of the species composition), patch area and patch species richness. We describe habitat specificity as a family of indices that may include either area or richness components, or none or both, and open for use of different types of mean in calculation of core habitat specificity. Core habitat specificity is a beta diversity measure: the effective number of completely distinct communities in the landscape. Habitat specificity weighted by species number is a gamma diversity measure: the effective number of species that a patch contributes to landscape richness. We compared 12 habitat specificity indices by theoretical reasoning and by use of field data (vascular plant species in SE Norwegian agricultural landscapes). Habitat specificity indices are strongly influenced by weights for patch area and patch species richness, and the relative contribution of rare vs. common species (type of mean). The relevance of properties emphasized by each habitat specificity index for evaluation of patches in a biodiversity context is discussed. Core habitat specificity is emphasized as an ecologically interpretable measure that specifically addresses patch uniqueness while habitat specificity weighted by species number combines species richness and species composition in ways relevant for conservation biological assessment. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.