DIET OF HARBOR PORPOISES IN THE KATTEGAT AND SKAGERRAK SEAS: ACCOUNTING FOR INDIVIDUAL VARIATION AND SAMPLE SIZE

Stomach contents of 112 bycaught harbor porpoises ( Phocoena phocoena ) collected between 1989 and 1996 in the Kattegat and Skagerrak seas were analyzed to describe diet composition and estimate prey size, to examine sample size requirements, and to compare juvenile and adult diets. Although porpoises preyed on a variety of species, only a few contributed substantially to the diet. Atlantic herring ( Clupea harengus ) was the dominating prey species for both juveniles and adults. Our results, in combination with those from previous studies, suggest that where herring is a dominant food source, porpoises prey primarily on size classes containing mature or maturing individuals. Further, we also show that Atlantic hagfish ( Myxine glutinosa ) may be an important food resource, at least for adult porpoises. Examination of sample size requirement showed that, depending on the taxonomic level used to describe the diet, a minimum of 35–71 stomachs are needed to be confident that all common prey species will be found.     

应用正交设计方法优化香蕉外植体直接出芽的条件

利用正交设计方法（L27（3^13)]研究了培养基中的植物生长调节物BAP,NAA和IBA,以及不同外植体对香蕉（Musa acuminata Colla.cv.Williams) 直接出芽频率的影响,外植体的不同是影响香蕉直接出芽频率的最主要因素,NAA和IBA对实验结果的影响相同,均弱于BAP,实验结果的统计分析表明,诱导香蕉外植体直接出芽的优选培养基为不添加BAP,NAA和IBA的MS基本培养基,最佳外植体为芽的顶端分生组织部分。     

截线法对西藏盘羊种群数量的估计

１９８７～１９９０年间,采用截线抽样法对西藏盘羊的种群数量及分布进行了全面调查。结果在１５５０ｋｍ样线上遇见９９头盘羊。由此资料,以傅立叶级数表达其探测函数,估计出了盘羊在西藏分布区内的平均分布密度为０．０８２０±０．００９７头／ｋｍ２,即每１２ｋｍ２约有１头,而波动在０．０１２１～０．３６７１头／ｋｍ２之间。并依此确定的１０．５万ｋｍ２的栖息面积计算、西藏盘羊的种群数量为８６３０±１０２１头。目前,盘羊群平均数下降为５～６头／群,亟待保护。     

群落有序样本的一种聚类分析方法

目前,适用于群落聚类分析有序样本的聚类方法主要是“最优分割法”。本文提出了一种新的适用于群落有序样本的聚类方法,该法较最优分割法计算简便。     

正交试验法优化长春花分化培养基

用正交设计方法研究了6BA、NAA和间苯三酚不同浓度配比对长春花细胞分化的影响,采用表L_(27)(3~(13))安排三因素三水平,并考虑了因素间的交互作用。获得高分化率的最优配比为:6BA,7.0mg/l;NAA,0.5mg/l;间苯三酚,1.0～5.0mg/l。     

SEXUAL SIZE DIMORPHISM AND REPRODUCTIVE INVESTMENT BY FEMALE SPIDERS: A COMPARATIVE ANALYSIS

We investigate the association between female reproductive investment, absolute size, and sexual size dimorphism in spiders to test the predictions of the fecundity-advantage hypothesis. The relationships between absolute size and sexual size dimorphism and aspects of female reproductive output are examined in comparative analyses using phylogenetically independent contrasts. We provide support for the idea that allometry for sexual dimorphism is the result of variation in female size more so than male size. Regression analyses suggest selection for increased fecundity in females. We argue that fecundity selection provides the only general explanation for the evolution of sexual size dimorphism in spiders.     

中国东北落叶松属植物rbcL 基因的序列分析及系统演化

长白落叶松的分类位置及与兴安落叶松的种间关系, 长期以来未有定论。本研究从大兴安岭、小兴安岭及张广才岭等6 个地点采集实验材料, 对其叶绿体DNA 的rbcL 基因进行PCR-RFLP 分析并测序。结果显示它们的rbcL 基因序列均没有差异, 表明东北地区落叶松属植物有共同起源。在系统演化上, 长白落叶松来自兴安落叶松(Larix gmelinii Rupr.), 应作为兴安落叶松的变种即L.gmelinii Rupr.var.olgensis Ostenfeld et S.Larsen     

双列杂交分析估算遗传参数两种方法的比较

本文就遗传参数的估算,对双列杂交分析中应用最广的Griffing法和Hayman法作了比较。结果表明,Hayman法估算非加性方差的结果比Griffing法小(p-1)/P~2_5~2, 而估算加性方差和遗传方差的结果则分别比Griffing法大2(p-1)/P~2_s~2和(p-1)/P~2_s~2。另外,本文还就造成两种方法分析结果不同的原因作了讨论。     

农药残留预测模型参数估计过程的灵敏度分析

本文根据矩阵理论运用摄动分析的方法,揭示了最小二乘法参数估计过程“病态”正规方程组问题,及运用“病态”正规方程组进行参数估计给预测模型带来的影响．最后根据矩阵的条件数理论,提出了对农药残留预测模型参数估计过程进行灵敏度分析的数学方法．     

ACC氧化酶和ACC合成酶反义RNA融合基因导入番茄和乙烯合成的抑制

从番茄品种强力米寿的总DNA中克隆番茄果实特异启动子2A11,以番茄成熟果实的RNA为模板,进行RT-PCR扩增,克隆番茄全长的ACC氧化酶基因和ACC合成酶基因片段。完成两个基因的克隆和测序后,将888bp的番茄ACC氧化酶基因和943bp的ACC合成酶基因片段串联,构成全长1837bp的融合基因。将该融合基因以反义的方向插入植物双元载体pYPX145中番茄果实表达特异启动子下游,获得ACC氧化酶基因和ACC合成酶基因融合的植物双元载体pOSACC。该载体外源基因表达单元的两端含两个烟草SAR序列,利于转基因的稳定遗传。以番茄栽培品种合作903子叶和下胚轴为外植体,利用根癌农杆菌进行基因转化,通过200mg/L卡那霉素选择和GUS检测,获得了105株番茄GUS阳性植株,转基因番茄果实在当代表现明显耐贮特点。经过4代的耐贮和果实农艺性状的综合选择,获得了两个表现良好的株系DR-1和DR-2,两株系果实乙烯释放量显著下降,是未转基因材料的9.5%,番茄的贮存期在50天以上。     

EVOLUTIONARY RELATIONSHIPS AMONG MULTIPLE MODES OF CELL DIVISION IN THE GENUS NANNOCHLORIS (CHLOROPHYTA) REVEALED BY GENOME SIZE, ACTIN GENE MULTIPLICITY, AND PHYLOGENY

A single cell divides to multiply, but not all cells follow the same pattern of division. We studied cell division in seven strains from six species belonging to the genus Nannochloris Naumann and classified their modes of cell division into three types: binary fission ( N. bacillaris Naumann), budding ( N. coccoides Naumann), and autosporulation resulting in the formation of two to four daughter cells ( N. maculata Butcher, N . sp. SAG 251-2, N. atomus Butcher CCAP 251/7 and SAG 14.87, and N. eucaryotum [Wilhelm et al.] Menzel and Wild). To determine the evolutionary relationships among these multiple modes of cell division, we investigated the strains' genome sizes, copy number of actin genes, and phylogeny. The genome sizes were determined by counter-clamped homogeneous electric fields electrophoresis and fluorimetry. The genomes are very small and range from 12.6 Mbp ( N. maculata ) to 47.4 Mbp ( N. atomus SAG 14.87). The genomes of Nannochloris species seem to be among the smallest for free-living eukaryotes. Nannochloris bacillaris (binary fission), N. coccoides (budding), Nannochloris sp. (two-cell type of autosporulation), and N. eucaryotum (multicell type of autosporulation) contain a single actin gene, whereas N. maculata (two-cell type of autosporulation) and two strains of N. atomus (two-cell type of autosporulation) contain two actin genes. This suggests that the actin gene was duplicated in this eukaryote, which has a very small genome. Phylogenetic analyses of partial actin gene sequences suggest that autosporulation is the ancestral mode of cell division.     

霍山石斛多组份综合鉴别及不同部位药用价值的关联分析

本文采用科学试验与数学分析相结合的方法,对霍山石斛的多种成份进行了综合考察,提出了一种鉴别霍山石斛的新方法,当关联度r＞0.927时,可以认为该石解为霍山石斛种．另外,对霍山石斛根及叶的药用价值作了探讨．发现其根和叶也有与茎相类似的有效成份分布（r＞0.88）,值得进一步开发利用．     

应用柯尔莫哥洛夫检验研究（0—1）变量与连续变量间的相关性

本文介绍了柯尔莫哥洛夫检验的基本思想,探讨了用柯尔英哥洛夫检验研究(0,1)变量与连续性变量相关的办法,并举例作了说明。     

海南岛热带山地雨林林分生物量估测方法比较分析

本文通过对海南岛热带山地雨林林分生物量估测方法的比较分析,表明材积转换法不适宜估算海南岛热带山地雨林林分生物量,其结果与皆伐法相比较一般偏高20％—40％;而用实测资料建立的生物量回归模型,对原始林林分有较好的估测结果,除树枝和树叶生物量外,树干、树皮及地上部分生物量的回归模型值,与皆伐法的结果比较,相对误差一般在±10％以内,为允许误差范围,而对热带山地雨林的更新林生物量的估测则效果较差,应建立相应的估测模型。平均木法有工作量小的优点,且误差也在16％以下,但要注意取样的树种多样性和取样强度,在实际中应当慎用。另外本文对测定热带山地雨林生物量(原始林)的所需面积大小问题作了研究,提出了生物量-面积曲线的概念,确定其最小调查面积为2500m~2以上。     

具有自竞争的赤眼蜂及农药灭螟数学模型的全局定性

本文对具有自竞争的赤眼蜂及农药灭螟的生态过程,建立了一个数学模型,改进了〔1〕,并对该模型利用作者〔2〕的制图定性新方法,获得模型生态平衡全局稳定的各类参数相关联的条件,为天敌及药物灭螟的综合治理研究,提供参考．     

马尾松毛虫的为害损失及管理效益的模拟研究

本文分析了马尾松受马尾松毛虫为害后,木材生长的损失情况,提出了一个马尾松中、幼龄单木生长模型,并在此基础上,模拟研究了马尾松受害后损失量的累积过程。结果表明,不同受害年龄,不同受害程度下,马尾松材积量损失明显不同,对于选择不同的防治措施具有重要意义。本文还结合一般化学防治方法,提出了一种防治效益的分析与评价的一般方法。