Genetic mapping of size-related quantitative trait loci (QTL) in the bay scallop (Argopecten irradians) using AFLP and microsatellite markers

We constructed genetic linkage maps for the bay scallop Argopecten irradians using AFLP and microsatellite markers and conducted composite interval mapping (CIM) of body-size-related traits. Three hundred seventeen AFLP and 10 microsatellite markers were used for map construction. The female parent map contained 120 markers in 15 linkage groups, spanning 479.6 cM with an average interval of 7.0 cM. The male parent map had 190 markers in 17 linkage groups, covering 883.8 cM at 7.2 cM per marker. The observed coverage was 70.4% for the female and 81.1% for the male map. Markers that were distorted toward the same direction were closely linked to each other on the genetic maps, suggesting the presence of genes important for survival. Six size-related traits, shell length, shell height, shell width, total weight, soft tissue weight, and shell weight, were measured for QTL mapping. The size data were significantly correlated with each other. We subjected the data, log transformed firstly, to a principle component analysis and use the first principle component for QTL mapping. CIM analysis revealed one significant QTL (LOD=2.69, 1000 permutation, P<0.05) in linkage group 3 on the female parent map. The mapping of size-related QTL in this study raises the possibility of improving the growth of bay scallops through marker-assisted selection. (c) 2007 Published by Elsevier B.V.

Growth and survival of reciprocal crosses between two bay scallops, Argopecten irradians concentricus Say and A-irradians irradians Lamarck

A complete diallel cross between two bay scallop populations, Argopecten irradians concentricus Say (M) and A. irradians irradians Lamarck (C), was carried out. Growth and survival were compared among hybrids and pure populations. No significant difference in the shell length was found among the four groups on the first day of D-larvae. On day 10, shell lengths of the two reciprocal crosses (CM, MC)(female x male ) were significantly greater than those of the CC (141.97 mu m) and MM (146.20 mu m) groups, with the growth rate of the MC (156.14 mu m) cross greater than that of the CM (155.35 mu m) cross. Also, heterosis for survival was significantly larger than that for growth. Both maternal origin and mating strategy had significant effects on growth and survival throughout the whole larval stage. Heterosis was also observed in later spat and adult stages. On day 170, the mean shell length, shell height and total weight of the CM cross were significantly larger than those of the other crosses (P<0.05). The results from this study indicate that hybridization between A. irradians concentricus and A. irradians irradians may be a promising way for genetic improvement of existing bay scallop brood stocks in China. (c) 2007 Elsevier B.V. All rights reserved.

祁连山海北高寒草甸紫外辐射与气象要素的关系

分析2003年祁连山海北高寒草甸地区UV—A，UV-B变化特征，以及与气象要素的相关性，并依有关要素模拟计算了UV—A，UV—B。结果表明：UV—A，UV—B日、年变化明显，年内6月达最高，12月最低。UV-A，UV-B年总量分别为138.11，35.14MJ／m^2。UV—A，UV—B占DR的比例也有明显的日、年变化，中午前后（夏季）高。早晚（冷季）低，年内分别为2.17％，0.54％。UV—A，UV-B与诸多的气象因子具有一定的显著性相关，但不能说明这些气象因子与UV有直接的影响作用，事实上是受DR影响的结果。采用DR，5cm土壤温度为预报因子，建立影响UV-A，1IV-B的旬相关模拟方程，且有极显著的二元线性回归检验水平。

围栏封育对青海湖地区芨芨草草原群落特征的影响

选择青海湖地区围栏内封育和围栏外自由放牧的芨芨草草地为研究对象，用样线和样方相结合的方法进行群落调查，分析了围栏内外芨芨草草地的群落特征和地上生物量特点。结果表明：多年围栏封育使围栏内外群落类型发生了变化，围栏内为芨芨草＋裸花碱茅群落，围栏外为芨芨草＋赖草群落，且每个小样方中的物种数围栏内大于围栏外。围栏内外芨芨草群落的相似性系数达0．743。围栏外自由放牧区域的芨芨草种群优势地位有所加强，其重要值也大于围栏内的芨芨草。物种丰富度指数围栏外大于围栏内，多样性指数中Shannon-winner指数、Hill指数和丰富度指数具有同样的趋势，而均匀度指数和Simpson指数则是围栏内大于围栏外。围栏封育后群落地上生物量发生变化，地上总生物量和禾草类生物量均为围栏内〉围栏外，而杂类草和豆类毒杂草则是围栏内〈围栏外。

黄绿蜜环菌蘑菇圈生长对土壤及植物群落的影响

通过调查青海省祁连县峨堡乡野生黄绿蜜环菌蘑菇圈发生季节蘑菇圈上、圈外植物群落的物种多样性、植物群落种类组成及多度变化,分析了蘑菇圈上、圈外土壤主要微生物类群的数量变化、土壤水分、速效养分、交换性阳离子及pH等的差异.结果表明,蘑菇圈上和圈外植物群落组成种类不同,圈上物种数明显高于圈外物种数;圈上各物种分盖度总和比圈外高出49.16%,但圈上和圈外优势种及主要伴生种相同.在0～10 cm土壤层,圈上土壤含水量、速效磷、硝态氮、氨态氮的含量明显高于圈外,但土壤有机质、交换性Ca2+、交换性Mg2+和pH值的变化不明显;在10～20 cm土壤层,圈上速效磷、硝态氮、氨态氮的含量仍明显高于圈外,但土壤含水量变化趋势相反,圈外高于圈上.在0～10cm土壤层,细菌、放线菌、真菌及纤维素分解菌的数量,均以圈上显著高于圈外(P＜0.05);在10～20cm土层,它们的数量差异不显著(P＜0.01).在两层土壤中,各类微生物数量表现为:细菌＞放线菌＞真菌＞纤维素分解菌.

藏药川西獐牙菜的引种栽培研究

川西獐牙菜(Swertia mussotii Franch.)是一种用于治疗黄疸型肝胆疾病和病毒性肝炎的珍稀藏药草本植物.引种栽培试验结果表明:在青海高原自然环境条件下,川西獐牙菜为2年生草本植物,完成植物生长发育约需10～12个月;植物种子在自然状态下萌发率较低,经低温处理后可明显提高萌发率;栽培川西獐牙菜的植株高度、分枝数量、单株生物量等生长指标明显高于野生植株,其有效化学成分可达到野生状态水平,说明野生川西獐牙菜的人工栽培是可行的.

河西绿洲区春小麦蒸腾蒸散的变化研究

在甘肃张掖绿洲区利用浮力称重式蒸散仪对春小麦蒸散量进行了测定，对蒸散量的日变化和季节变化特征进行了论述。研究结果表明：小麦田的日蒸散量在白天１２∶００～１６∶００达到最大，夜间２０∶００～０８∶００最小甚至呈负值。灌溉前后蒸腾强度出现峰值的时间有所变化。但灌溉以后，蒸腾与蒸散量均呈增大趋势。日蒸散量随着净辐射的增加而加大。在小麦不同的生育阶段，蒸散量有所不同，小麦拔节以前较小，拔节以后开始增大，灌浆期达到最大，接近成熟时逐渐降低。

Status and dynamics of Kobresia pygmaea ecosystem on the Tibetan plateau

This paper provides information about the distribution, structure, and ecology of the world's largest alpine ecosystem, the Kobresia pygmaea pastures in the southeastern Tibetan plateau. The environmental importance of these Cyperaceae mats derives from the extremely firm turf, which protects large surfaces against erosion, including the headwaters of the Huang He, Yangtze, Mekong, Salween, and Brahmaputra. The emphasis of the present article is on the climate-driven evolution and recent dynamics of these mats under the grazing impact of small mammals and livestock. Considering pedological analyses, radiocarbon datings, and results from exclosure experiments, we hypothesize that the majority of K. pygmaea mats are human-induced and replace forests, scrub, and taller grasslands. At present, the carrying capacity is increasingly exceeded, and reinforced settlement of nomads threatens this ecosystem especially in its drier part, where small mammals become strong competitors with livestock and the removal of the turf is irreversible. Examples of rehabilitation measures are given.

红枫湖水体中活性汞和溶解气态汞的分布特征及其控制因素

基于二次金汞齐结合冷原子荧光测定法对红枫湖活性汞（RHg）和溶解气态汞（DGM）的时空分布特征及其控制因素进行了研究.红枫湖溶解气态汞含量（ρ（DGM））为0.024-0.110 ng/L,随着水深的增加ρ（DGM）降低,且夏季高,冬季低,这种分布特征表明光在原子态汞的形成中起着重要的作用.红枫湖ρ（DGM）除受光强影响外,还受到春季后五大量生长的藻类影响,但与溶解性有机碳含量（ρ（DOC））及温度的相关性不大.活性汞含量（ρ（RHg））为0.14-2.70 ng/L,其主要受Hg^2＋的光致还原过程,Hg^2＋的甲基化过程以及人为源的释放等因素的控制

凯氏蒸馏法和元素分析仪法测定沉积物中全氮含量的异同及其意义

氮循环是生物地球化学研究领域中最重要的课题之一，全氮含量的测定是农业、生物和环境等多领域研究中的常规测试项目。凯氏蒸馏法和元素分析仪法作为常规方法通用于上述领域的全氮含量测定，但两种方法在实际应用中的差异却常被忽视。通过对中国北方某盐湖沉积物序列近百个样品的全氮含量分析，对两种方法测定结果的异同进行了对比研究。凯氏蒸馏法的分析精密度高于元素分析仪法(前者标准偏差为0.007,后者为0.024)，但在样品硝态和亚硝态氮的含量较高时，凯氏蒸馏法所测结果显著低于元素分析仪法的测定结果，此时选择元素分析仪法进行全氮含量的测定更为可靠和准确；对硝态和亚硝态氮含量极低的样品，两种方法的测定结果无显著差异。研究表明，选择全氮含量的测定方法，必须对所测样品的无机氮含量有初步的了解。对于中国北方的多数盐湖和地表环境样品，由于其无机氮的含量较高，选择凯氏蒸馏法进行全氮含量的测定是不适当的。尽管如此，对所研究的湖泊沉积物剖面而言，两种方法的对比却可以提供有价值的气候和环境演变信息。随着沉积物剖面的由深到浅，两种方法的测定结果由一致变化到存在显著差异，表明了湖泊水体从早期的淡水向今天的盐湖演化的过程。因此，凯氏蒸馏法和元素分析仪法测定结果的差异可以作为一种独立的地球化学气候代用指标。

湖泊沉积物中全氮含量的测定及其环境意义

全氮含量是环境、生物和农业等多领域的常规测试项目.作为全氮含量测定的常规方法,凯氏蒸馏法和元素分析仪法在实际应用中的差异却常被忽视.通过对中国北方盐湖沉积物序列近百个样品的全氮含量分析,我们对两法测定结果的异同进行了对比研究.结果表明,凯氏法的精密度高于分析仪法(前者标准偏差为0.007,后者为0.024),凯氏法和分析仪法测定全氮含量的差异为硝态和亚硝态氮的含量,因此,选择全氮含量的测定方法,必须对所测样品的无机氮含量有初步的了解.对于中国北方的多数盐湖和地表环境样品,由于其无机氮的含量较高,选择凯氏蒸馏法进行全氮含量的测定是不适当的.尽管如此,对我们所研究的湖泊沉积物剖面而言,两种方法的对比却可以提供有价值的气候和环境演变信息.随着沉积物剖面的由深到浅,两种方法的测定结果由一致变化到存在显著差异,表明了湖泊水体从早期的淡水向今天的盐湖演化的过程.因此,凯氏法和元素分析法测定结果的差异可以作为一种独立的地球化学气候代用指标.

巢湖悬浮物中稀土元素（REE）的物源精确示踪作用

采用化学连续提取和等离子质谱仪（ICP-MS）测定法,对安徽巢湖悬浮颗粒物中稀土元素的含量、赋存形态和配分模式进行了研究，结果表明：巢湖悬浮物中稀土总量在19，20-174，82mg/kg之间,东西两个湖区含量差异明显,东半湖区高于西半湖区，巢湖东西湖区悬浮物残渣态稀土元素具有截然不同的页岩标准化配分模式,东半湖区为轻稀土富集型,西半湖区为重稀土富集型,说明巢湖东西湖区具有明显不同的物质来源，巢湖东半湖区和西半湖区悬浮物稀土元素赋存形态比例也不同,东半湖区为残渣态〉铁锰氧化物结合态》有机结合态、AEC态;西半湖区为铁锰氧化物结合态〉残渣态》有机结合态、AEC态,这是由于巢湖水体从西到东受到的污染强度减轻造成的,稀土元素赋存形态可以作为判别湖泊污染程度的新依据.