Notes on the Bathypelagic Fauna of the Seas Around South Africa

The preliminary results of a study of the endemic giant tortoise population of Aldabra Atoll in the Indian Ocean (Geochehne gigantea Schweigger) are briefly described. Their number would appear to have increased dramatically since the turn of the century to their present level of some 141 000 individuals. Crude estimates of mortality and reproductive rates are also given.     

Analysis of the spawning stock–recruitment relationship of vendace (Coregonus albula (L.)) with evaluation of alternative models, additional variables, biases and errors

Abstract –  Spawning biomass and recruitment data for vendace from a central Finnish lake were analysed by fitting various recruitment models and comparing the fits statistically. The compensatory models of Ricker, Cushing and Beverton & Holt fitted the data better than the H ₀ hypothesis of constant proportionality, but model and parameter uncertainties were high. Additional variables were included in an attempt to reduce uncertainties. Heavy wind forcing during the first month after hatching of larvae reduced the recruitment success. For the Ricker and the Cushing models, recruitment seemed to be also negatively associated with the density of the previous year-class. The r ² increased considerably with inclusion of these additional variables, but the precision of model parameters remained low. Monte Carlo simulation of a vendace stock was applied to evaluate the interference of biases from the measurement error (ME) and time series error (TSE) in the analysis. Especially in the case of the Cushing model, compensatory density dependence can be overestimated severely. Increasing the number of observations decreases the biases in some cases. In view of potential biases and uncertainties, a precautionary management policy is recommended.     

巨峰系葡萄品种演化及分类的研究

 通过对巨峰系葡萄品种引种和性状观察记载以及选育途径和亲子代资料的分析，研究了它们的演化过程和分类方法，绘制了巨峰系葡萄品种演化图。巨峰系葡萄品种选育的最主要途径为杂交育种、其次为芽变选种和实生选种。巨峰系葡萄品种可按其来源、成熟期、成熟时果皮的色泽和种子有无进行分类。     

国产青步甲属Chlaenius的分类（鞘翅目，步甲科）

为了便于鉴定害虫天敌青步甲属Ｃｈｌａｅｎｉｕｓ的种类，这里，提供了国产青步甲属的分群检索表，分述了国产青步甲１５个群的特征，以及１９个国产种的主要特征。在这１９个国产种中，有２种只在台湾发现。文中附有１９个国产种的外生殖器形态图；文后附有１０个国产种的外生殖器显微照片，以供鉴定种类时作参考。     

杂交稻部分不育系与恢复系的SSR分类

选用分布于水稻(Oryza sativa L.)12条染色体上的36对SSR(simple sequence repeats)引物，分析了5个光温敏核不育系、7个细胞质雄性不育系及54份来自不同生态类型恢复系或品种的遗传差异。在供试材料中共检测出300条多态性片段，平均每对SSR引物检测到8.33条。分析结果表明，(1) SSR标记明确地把供试的66份水稻材料中的65份区分开来，和已知系谱的亲缘关系多数吻合，与表型性状聚类结果也有一定的相似性。(2) 以GD=0.73为标准，可准确地将籼稻、粳稻、野生稻三大类区分开；以GD=0.63为标准，又可区分出籼稻大类中带有粳稻或野生稻血缘的品种。表明SSR标记对籼稻、粳稻、野生稻品种的分类灵敏度高、结果可靠；并筛选出可用于鉴别水稻籼粳类型的10对特异性引物。(3) 以GD=0.56为标准，将供试材料划分在8个生态类型中，为生产上杂优组合亲本的选配提供了一些有益的参考。同时，生产上常用的一些杂交稻亲本划分在不同的生态类型中，表明强优势组合亲本间的遗传差异一般较大。     

The occurrence of primary burrowing crayfish in terrestrial habitat

A researcher’s perception of a target species’ landscape strongly influences the design of habitat studies conducted at broad spatial scales. Consequently, researcher-dependent perceptions may misguide conservation efforts. Although the life histories of some crayfish (i.e., primary burrowers) are centered on a fossorial existence independent of surface water, all North American crayfish are viewed in an aquatic context. This paradigm restricts the range of habitats that are typically sampled and managed for crayfish conservation. This study used presence/absence of the primary burrower Distocambarus crockeri at 137 locations within the Long Cane Ranger District of the Sumter National Forest, South Carolina, USA, to model the habitat association of the species across a GIS-based landscape. Logistic regression indicated that D. crockeri presence was most strongly associated with a terrestrial habitat defined by a set of morphologically similar soils located along ridge tops. Furthermore, the species was negatively associated with aquatic habitats such as streams and floodplains. The results indicate that D. crockeri is a terrestrial habitat specialist and should be modeled and managed at the landscape as a terrestrial organism. When viewed as a subset of the total United States cambarid fauna, primary burrowers are disproportionately imperiled. Primary burrowers comprise only 15% of the total crayfish fauna, while they account for 32% of those crayfish ranked critically imperiled. Habitat loss and an aquatic bias that restricted sampling to aquatic and semi-aquatic habitats might explain the group’s disproportionate imperilment.     

关于土壤系统分类中一些诊断层的鉴别

本文对中国土壤系统分类中的黏化层、雏形层、铁铝层和低活性富铁层的鉴别作进一步讨论。     

浙江省石灰土光谱特征及其自动识别分类技术研究

本文通过石灰土专题调查，室内土壤光谱测定及其特定及其特征分析，并在此基础上进行土壤光谱自动识别分类方法的对比试验。明确了浙江省石灰土的四个土类，六个土属的光谱特征分异规律；提出了一种参数少，运算量小，精度高的光谱自动识别新方法－分层提取判别法。     

Variation of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) and its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.)

The domestication of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) is briefly discussed. Using data documented as a matter of routine in genebank work, 63 accessions of cultivated flax from the flax germplasm collection of the Gatersleben Genebank are compared with 73 accessions of its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.), which have been observed in systematic field trials. Range of variation, genetically based variation, heritability and correlation of several characters are considered, especially with respect to the influence of domestication. Cultivated flax shows higher variation in the characters of generative plant parts, while pale flax varies more in the vegetative parts of the plant. The character correlations are similar in both subspecies. Of the 29 characters studied in pale flax the parameters describing tillering, height of plant, weight of seeds, width of petals and width of leaves are especially suitable for distinguishing between different accessions. In spite of the high heritabilities of most of the characters, the influence of the environment is significant in most cases.