基于模糊理论预测CpG岛新方法

启动子区域的CpG岛的异常甲基化是识别癌症的重要标志之一。目前已经建立的一些CpG岛的预测思想和方法都有自身的缺点,基于模糊理论的预测思想从贴进度的角度来判定CpG岛,能更容易地找到被以往方法所忽略的具有更多生物学意义的CpG岛。本研究通过构建属于CpG岛集合的隶属函数,计算候选序列的隶属度,找出所有的可接受隶属程度的CpG岛。将该方法应用于UCSC数据库中的一段序列（hg18．chr1．31618510.31623510.-1000）进行预测,发现提高了预测的精确度。可见应用模糊理论预测CpG岛具有一定的可行性,利用选取不同的截集,可以得到更为精确的CpG岛。     

32个切花菊品种的耐低磷特性

本研究利用砂培试验对32个切花菊品种进行了苗期耐低磷筛选和鉴定。结果表明,供试切花菊品种耐低磷能力存在明显的基因型差异,表现在幼苗相对干重（低磷胁迫/正常供磷）、相对磷含量和相对磷积累量存在较大的基因型间变异(CV分别为12.14%、20.99%和26.41%),相对干重、相对磷含量和相对磷积累量之间均呈极显著正相关(P<0.01)。通过聚类分析可将32份供试品种的耐低磷胁迫能力分为极强、强、中等、弱、极弱5个级别,‘南农银山’对低磷的忍耐能力最强,属耐低磷能力极强的品种;‘南农红枫’、‘南农香槟’和‘优香’对低磷胁迫的忍耐能力最差,属耐低磷能力极弱的品种。相对干重、相对磷含量和相对磷积累量可作为切花菊耐低磷特性的筛选指标,为切花菊育种、栽培管理、磷营养学研究提供参考。     

多镜联合治疗胆总管结石合并胆囊结石的技术优势

目的探讨十二指肠镜、胆道镜、腹腔镜等多镜联合治疗胆总管结石合并胆囊结石的技术优势。方法采用腹腔镜胆总管探查术+腹腔镜胆囊切除术(LCBDE+LC)和内窥镜逆行胰胆管造影术+内窥镜下括约肌切开取石术+腹腔镜胆囊切除术(ERCP+EST+LC)两种术式治疗胆总管结石合并胆囊结石患者。结果有两组病例,其中LCBDE+LC组36例,本组术后胆道残余结石2例,后经T管窦道行胆道镜取石治愈。ERCP+EST+LC组54例,本组术后并发一过性高淀粉酶血症3例,发生急性轻型胰腺炎2例。结论多镜联合治疗胆总管结石合并胆囊结石具有创伤小、效果好、并发症少、恢复快的优点,多镜联合发挥出其独特技术优势,避免了因接受传统开腹手术而造成较大创伤的不合理治疗模式。     

不同R∶FR值对菊花叶片气孔特征和气孔导度的影响

以切花菊品种"神马(Jinba)"为试材,2010年10月至2011年2月间在南京信息工程大学试验温室采用不同Red (660±10) nm: Far-red (730±10) nm值的LED光源短日处理,研究了温室切花菊叶片气孔特征和气孔导度对不同R∶FR值的响应。结果表明:不同R∶FR值短日处理35d菊花叶片的上表皮和下表皮的气孔直径分别以R∶FR值4.5和6.5处理最大,均以R∶FR值2.5处理最小,气孔密度和气孔开度均以R∶FR=2.5处理最高,以R∶FR值6.5处理最低,下表皮的气孔密度、气孔开度明显高于上表皮;不同R∶FR值处理叶片的气孔开张比和气孔指数差异不显著;在相同光强下,菊花叶片气孔导度和光合速率由大到小的R∶FR值顺序依次为2.5、4.5、0.5、6.5。叶片气孔导度与气孔指数、气孔密度、气孔开张比和气孔开度成正相关,与气孔长度和气孔宽度呈负相关;R∶FR值在2.5-6.5范围内,随光质中红光成分增加,叶片气孔密度、气孔指数、气孔开度、气孔开张比和气孔导度显著降低。     

Canopy status modulates formation of wood rays in scots pine under hemiboreal conditions

Non-structural carbohydrates (NSC) reserves are crucial for trees to cope with weather extremes, thus to ensure their survival and ecological plasticity. The NSC reserves can depend on social status, suggesting uneven plasticity of trees at the stand level. In stemwood of Scots pine (Pinus sylvestris L.), which is a widespread and important species, NSC reserves are stored in parenchyma in wood rays (WR). The quantity of WRs is adjusted intra-annually, allowing retrospective analysis of factors affecting their formation. Accordingly, the differences in WR quantity in stemwood of dominant and intermediate (canopy trees with reduced and narrow crowns) maturing Scots pine were assessed by quantitative wood anatomy. Tangential cuts from the outermost 30 tree-rings were analysed. The relative ray area was intermediate, i.e. covering about 5% of the tangential cut, yet expressed high individuality among the trees. The size and amount of WR mainly differed between the earlywood and latewood; WRs in latewood were higher although narrower in comparison to earlywood, yet their total amount was higher in earlywood. Canopy status had only a slight effect, as quantity and height of WR tended to be higher for the intermediate trees, particularly in earlywood. The size and quantity of WR expressed inter-annual variation, which was mainly related to the meteorological conditions prior to the formation of the tree-ring (previous summer and autumn) indicating legacy effects of climatic factors on NSC and susceptibility of trees to cumulative effects of weather extremes. However, the climatic signals in the inter-annual variation of WR were weaker than observed before, likely due to location of the studied stand in the mid-part of the species range. Nevertheless, the observed differences in mean values and inter-annual variation of WR suggested a within-species diversity of carbon allocation patterns, supporting adaptability of the species.     

A broader ecological context to habitat fragmentation: Why matrix habitat is more important than we thought

Abstract. Consequences of habitat fragmentation have garnered much attention over the past few decades. The resulting literature has been useful for understanding how land‐use changes influence population viability and community structure, but we are still hampered by a major aspect of the conceptual framework within which most fragmentation work arises. Specifically, habitat between fragments (‘matrix’) is usually treated as uniform and ecologically irrelevant. However, recent work on animals shows that matrix habitat can profoundly influence within‐fragment dynamics. We review related evidence for plants. Various matrix types (e.g. clear‐cutting, agriculture, or urbanization) can act in different ways to alter resource availability and movement of pollinators, seed dispersers, and herbivores. Inclusion of matrix qualities in fragmentation studies is further complicated since most matrices are not static; sites in which timber harvesting or agriculture occur develop through succession or change as crops are rotated, respectively, such that their influence on within‐fragment processes vary temporally. Also, many plants are not restricted to remnants of original habitat. Using studies of forest understory plants, we summarize work showing how diversity can change significantly through time in matrix. Understanding the persistence of a species across fragmented landscapes will require more attention to matrix habitat, and to the species utilizing the matrix.     

切花荷兰鸢尾(Iris xiphium L. var. hybridum)低温处理与保鲜

在不同条件下,对荷兰鸢尾金皇后（Iris xiphium L.var.hybridum cv.Yellow Queen）和罗萨里奥（Iris xiphium L.var.hybridum cv.Rosarlo）品种的鲜切花材料进行了预冷和冷藏处理试验。结果表明：相同预冷和冷藏处理条件下,这2个品种切花的保鲜效果基本无差别。在不添加任何化学试剂且处理温度为2-4℃条件下,预冷处理以花蕾初现色期、相对湿度20％-30％且处理时间12-24h的保鲜效果为佳,其保鲜期比对照平均延长3-4d;冷藏处理以花蕾未现色或刚现色的切花材料,装入不完全密封的塑料薄膜袋中,袋中相对湿度为95％-98％的处理条件效果最佳,保鲜期可达7-10d。     

乙烯在切花衰老中的作用(综述)

切花衰老是基因表达激活和蛋白质合成受到高度调控的过程。切花衰老所伴随的生理生化变化包括水解酶活性上升、大分子物质降解、呼吸作用增强和类似呼吸跃变的乙烯合成剧增等。乙烯的生成及其作用是切花衰老研究中十分重要的内容。本文综述乙烯在切花衰老过程中调控作用的研究现状。     

氮素对日光温室独本菊品种‘神马’干物质分配影响的模拟

 为定量研究氮素对日光温室独本菊(Dendranthema morifolium)干物质分配的影响, 该研究以独本菊品种‘神马’为试验材料, 于2005年10月～2006年7月在北京日光温室内进行了不同定植期和不同氮素水平的栽培试验, 以生理辐热积为发育尺度, 定量分析了氮素对独本菊品种‘神马’干物质分配指数动态的影响, 建立了氮素对日光温室独本菊品种‘神马’干物质分配影响的模拟模型, 并用与建立模型相独立的数据对模型进行了检验。结果表明, 独本菊品种‘神马’叶片累积氮含量最大值出现在现蕾期, 现蕾期叶片累积氮含量适宜值为1.62 g&#8226;m^–2。模型对日光温室独本菊品种‘神马’各器官干重预测结果较好, 茎、叶和花干重的预测值与实测值之间基于1:1线的决定系数分别为0.94、0.97和0.94, 相对预测误差分别为10.3%、5.76%和4.02%。该研究建立的模型可以根据温室内的气温、太阳辐射、日长和现蕾期叶片累积氮含量预测日光温室独本菊品种‘神马’各个器官干重随生育时期的动态变化, 从而为日光温室独本菊品种‘神马’生产中氮素的优化管理提供决策支持。