中国海域斑海豹种群资源和分子遗传特征研究

斑海豹，西北太平洋广泛分布的冷水性海洋哺乳动物，为我国的二类保护野生动物，属于濒危物种，也是唯一能在我国海域自然繁殖的鳍脚类动物。辽东湾结冰区是斑海豹在世界上8个繁殖区中最南端的一个。为了能够更好地保护斑海豹资源，对渤海海域斑海豹的栖息地、种群动态及分布时间、重金属体内积累、以及斑海豹的分子遗传特性进行了研究。结果如下： 斑海豹在渤海海域的栖息地有辽宁双台子河口水域、大连虎平岛和山东庙岛群岛海域三处，其中的上岸点分别为河口泥沙滩、海里的浅石滩和海岛周围的小岛礁三种类型。斑海豹出现在三个栖息地的时间为每年的3~5月，2002~2008年间各栖息地的斑海豹的数量变化不明显。 对斑海豹肌肉、肝和肾脏组织重金属元素含量的分析结果显示，汞（Hg）、镉（Cd）、铅（Pb）和砷（As）等有毒元素在斑海豹体内的积累远未达到致死浓度。 对斑海豹的部分mtDNA 序列分析发现，辽东湾斑海豹群体的遗传距离、控制区DNA的单元型多样度和核苷酸多样度均远小于日本群体，辽东湾群体的遗传多样性水平较低。 微卫星引物标记对辽东湾斑海豹群体的遗传多样性研究显示，平均有效等位基因数（2~4个）和期望杂合度（0.24~0.72）等指标均较低，表明辽东湾斑海豹群体遗传多样性水平下降，可能曾出现过一定程度的瓶颈效应。 对斑海豹的41个MHC-I基因的序列分析，得到40个等位基因。斑海豹MHC-I基因多态性水平高，说明辽东湾斑海豹种群MHC-I基因的丰富性。 以上研究结果对于我国辽东湾斑海豹种群的保护和管理具有一定意义。

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.