五条河流青海湖裸鲤的同工酶变异

为全面了解青海湖裸鲤遗传多样性现状,采用水平淀粉凝胶电泳技术分析了青海湖裸鲤[样品采自青海湖的五条支流,分别为泉吉河(QJ)、沙柳河(SL)、哈尔盖河(HEG)、布哈河(BH)以及甘子河(GZ)]的13种同工酶,共记录26个位点,统计了基因频率,计算了其遗传多样性。结果表明:26个基因位点中多态位点6个,分别为Pgm、Hk、Cat、Gdh、Es-t1、S-Mdh,多态位点比例(P0.99)为23.08%,表明青海湖裸鲤的五个群体皆具有较高的遗传多样性水平;分别计算了五个群体的平均杂合度(H)为0.1161(HEG)、0.1178(GZ)、0.1304(SL)、0.1305(BH)、0.1287(QJ),多态位点比例(Ae)分别为1.3112(BH)、1.3069(SL)、1.2542(GZ)、1.2492(HEG)、1.2453(QJ);除泉吉河群体外,其它四个群体的遗传偏离指数均为负数,表明多数群体处于一定程度的杂合子缺失状态;计算了五个群体间的遗传距离以及遗传相似度,结果显示群体间遗传距离与遗传相似度与各个河流的地理位置具有很强的相关性;根据五个群体的遗传距离进行了聚类分析,通过构建系统树图将其基本分为两大种群,甘子河与哈尔盖河两群体为一类群,另外三个群体分为一个类群;计算群体间的基因流(Nm)为7.2013,说明河道之间具有较为广泛的基因交流,并计算了两两群体间的基因流,其中布哈河群体与其它群体间的基因交流都较为广泛。     

Comparison of growth-climate relationship of sabina przewalskii at different timberlines along a precipitation gradient in the northeast Qinghai-Xizang Plateau,China北大核心CSCD

Aims To test the hypothesis that water is the main limiting factor of tree growth at the arid alpine timberline, and to explore the effects of water on growth-climate relationships of Sabina przewalskii along a precipitation gradient in the northeast Qinghai-Xizang Plateau. Methods Three sides were selected to sample the alpine timberline along a precipitation gradient in the northeast Qinghai-Xizang Plateau: Halihatu National Forest Park in Wulan County (HL, annual precipitation 217 mm), Qushigang in Dulan County (QS, 281 mm) and Hebei Forest Farm in Tongde County (HB, 470 mm). The correlation and response analysis at seasonal and extreme climate year scales were used to examine the spatial variations of the growth-climate relationship of S. przewalskii at different timberlines. Important findings Our results do not support the hypothesis that water is the main limiting factor of tree growth at the arid alpine timberline. The effect of precipitation on the radial growth of S. przewalskii were consistent across all three sampling sites, while the effects of temperature were different across sites. At HL site (low precipitation), the winter and summer minimum temperature were the main limiting factor of S. przewalskii radial growth, and this relationship did not significantly change in different extreme climate years. At QS site (middle precipitation), the radial growth of S. przewalskii was mainly limited by the minimum temperature in spring and summer, but its effect was weaker than that at low precipitation site. At HB site (high precipitation), the spring temperature had a significant negative effect on tree growth, and the positive effect of spring precipitation on tree growth was significantly enhanced in comparison with those at low and middle precipitation sites, especially in extreme high temperature and drought years. Summer precipitation did not significantly affect tree growth at high precipitation site. Our results did not support the hypothesis that the radial growth of trees at alpine timberline in arid/humid area is mainly limited by water/temperature. However, precipitation at timberline will affect the relationship between tree growth and temperature at different seasons. With the warming and humidification of the northeastern Qinghai-Xizang Plateau, the climatic limiting factors of tree growth in different timberline areas may be complicated. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All rights reserved.     

Validation of daily increment formation in otoliths for Gymnocypris selincuoensis in the Tibetan Plateau,China

Daily increment validation in fish otolith is fundamental to studies on fish otolith microstructure, age determination and life history traits, and thus is critical for species conservation and fishery management. However, it has never been done for Schizothoracine fish, which is the dominant component of fish fauna in the Tibetan Plateau. This study validated the daily increment formation of Gymnocypris selincuoensis, as a representative of Schizothoracine fish, by monitoring the growth of hatchery‐reared larvae group and wild‐caught post‐yolk‐sac larvae group under controlled experiments. The results from monitoring the hatchery‐reared larvae group showed that sagittae and lapilli were found in yolk‐sac larvae, and formed 5–7 days before hatching, but asterisci were not found until 11 days post‐hatching. The first increment in sagittae and lapilli was formed in the first day after hatching. The daily periodicity of increment formation was examined and confirmed in sagittae and lapilli of both larvae groups. However, sagittae were better for age determination than lapilli for larvae at earlier days. For larval G. selincuoensis older than 50 days, lapilli were the only otolith pair suitable for larvae daily age determination. This study validated the daily increment formation in Schizothoracine fish for the first time has primary implications to other fishes from this subfamily.     

基于MaxEnt模拟人类活动与环境因子对青藏高原特有植物祁连獐牙菜潜在分布的影响

以青藏高原特有植物祁连獐牙菜(Swertia przewalskii Pissjauk.)为材料,基于该物种18个种群分布点及8个生物气候变量、海拔变量以及人类活动强度变量,运用最大熵模型(Max Ent)和ArcGIS技术分别构建当前气候情景下及人类活动影响下祁连獐牙菜的适宜生境预测模型,研究人类活动及自然环境变量对祁连獐牙菜空间分布的影响。结果显示,人类活动影响下的训练集和测试集的AUC值均小于无人类活动干扰的AUC值,人类活动与祁连獐牙菜分布呈负相关。限制祁连獐牙菜分布的主要变量为海拔、等温性、人类活动足迹指数及平均温度日较差。当前气候情景下祁连獐牙菜的最适宜生境占祁连山国家公园青海片区总面积的36.6%,有利于该物种的保护和恢复,而位于门源县和祁连县保护区内一般控制区的潜在生境受到人为干扰的可能性较大,应加强关注和保护。     

线粒体控制区在鱼类种内遗传分化中的意义

线粒体DNA（mtDNA）作为分子标记已被广泛应用于各物种系统发生的研究。mtDNA控制区序列（D-Loop）以其较高的突变积累对于研究物种种内的遗传分化具有重要价值。鱼类是脊椎动物中最原始但在种属数量上又最占优势的类群,其物种繁多,分布广泛,起源复杂,研究其系统发生历来是令人饶有兴趣的课题。D-Loop在研究鱼类种内遗传分化中具有多方面的重要意义。近年来,已有越来越多的研究工作将D-Loop作为分子标记来探讨各种鱼类的种内遗传分化,并且获得了许多有启发性的结果。青海湖是我国内陆最大的咸水湖,湖中主要鱼类为青海湖裸鲤（Gymnocypris przewalskii）,D-Loop分析初步结果显示青海湖及其周围河流中的裸鲤似乎没有新的种内遗传分化现象。      

Otolith Microstructure of Larval Gymnocypris potanini Herzenstein from the Minjiang River in China

Synopsis Otolith microstructure of about 120 Gymnocypris potanini larvae from the Minjiang River in China was examined and analyzed. Larvae had multiple primordia in most lapilli and sagittae, while had only one primordium in a few specimens. There had only one nucleus in otoliths of the larvae, except for some few specimens with 2 nuclei. The transparence of many otoliths differed from center to edge, and part of them could be divided into inner low optically dense zone (LODZ) and outer optically dense zone (ODZ). Based on increment clarity, otoliths of this species could be classified into three types, which were otolith with subtile increments, otolith with almost identified increments, and otolith with fairly clear increments characterized by high contrast. The last two types of otolith accounted for 87.07% in lapilli and 94.46% in sagittae, respectively. Increment clarity of sagitta was higher than that of lapillus. Natural checks were identified in 32.50% lapilli and 48.33% sagittae. These checks primarily located in the first to sixth increment. According to the number of increments in otoliths, the age of this batch larvae was 14 – 22 days, birth date was on June 17 – 25, and average growth rate of body length was 0.8936 ± 0.08769 mm/d.     

Physiological responses of Populus przewalskii to oxidative burst caused by drought stress

We measured dry matter accumulation and allocation to the roots, leaf gas exchange, chlorophyll fluorescence, antioxidant enzymes, and ABA and polyamine (PA) contents in Populus przewalskii under three different watering regimes (100, 50, and 25% of the field capacity) to investigate the morphological and physiological responses to water deficit in woody plants. The results showed that drought stress retarded P. przewalskii as evident from a decreased biomass accumulation and the reduced increment of shoot height and basal diameter. Drought stress also affected the biomass partition by higher biomass allocated to the root systems for water uptake. The contents of ABA and PAs especially were increased under stressful conditions. Drought stress caused oxidative burst indicated by the accumulation of peroxide (H₂O₂), and fluorimetric detection also confirmed the increased accumulation of H₂O₂. The antioxidant enzymes, including superoxide dimutase, peroxidase, ascorbate peroxidase, and reductase, were activated to bring the reactive oxygen species to their homeostasis; however, oxidative damages to lipids, proteins, and membranes were significantly manifested by the increase in total carbonyl (C=O) and electric conductance (EC).     

Male infanticide and paternity analyses in a socially natural herd of Przewalski's horses: Sexual selection?

The sexual selection hypothesis explains infanticide by males in many mammals. In our 11-year study, we investigated this hypothesis in a herd of Przewalski's horses where we had witnessed infanticidal attacks. Infanticide was highly conditional and not simply linked to takeovers. Attacks occurred in only five of 39 cases following a takeover, and DNA paternity revealed that, although infanticidal stallions were not the genetic fathers in four cases out of five, stallions present at birth did not significantly attempt to kill unrelated foals. Infanticide did not reduce birth intervals; only in one case out of five was the infanticidal stallion, the father of the next foal; mothers whose foals were attacked subsequently avoided associating with infanticidal stallions. Therefore, evidence for the sexual selection hypothesis was weak. The “human disturbance” hypothesis received some support, as only zoo bred stallions which grew up in unnatural social groups attacked foals of mares which were pregnant during takeovers.     

Dietary Overlap of Przewalski's Gazelle,Tibetan Gazelle,and Tibetan Sheep on the Qinghai-Tibet Plateau

Abstract: We studied food composition and overlap among sympatric Przewalski's gazelle (Procapra przewalskii), Tibetan gazelle (P. picticaudata), and Tibetan domestic sheep (Ovis aries) in the Upper Buha River, Qinghai-Tibet Plateau, using microscopic fecal analysis. The 2 gazelles forage mainly on plants from Leguminosae and Compositae families and domestic sheep feed mainly on Gramineae and Cyperaceae. The dietary overlap index between the 2 gazelles and Tibetan domestic sheep increased from 0.43 to 0.58 during the plant-growing period to 0.76–0.77 during the plant-withering period, which indicated competition for foods intensified during the food-limited season. Although the 2 gazelle ate similar diets, they might avoid food competition by occupying different foraging areas. We suggest reducing numbers of overwintering Tibetan domestic sheep on pastures to lessen survival pressure on the endangered gazelles during winters.     

不同生境下青海湖裸鲤(Gymnocypris przewalskii)两亚种鳃形态差异及其功能适应

该研究比较观察青海湖裸鲤(Gymnocypris przewalskii)两亚种(青海湖裸鲤指名亚种(Gymnocypris przewalskii przewalskii)和青海湖裸鲤甘子河亚种(Gymnocypris przewalskii ganzihonensis))鳃的形态及显微结构。结果显示,指名亚种的第一鳃弓鳃耙数多、密集且较长,而甘子河亚种则耙数少、稀疏且短;两者的鳃丝间距及鳃小片间距无明显差异,指名亚种的鳃丝较长;指名亚种扁平上皮细胞形态以不规则椭圆形为主,鳃丝表面有黏液细胞,其上分布的氯细胞数量多于甘子河亚种,而甘子河亚种扁平上皮细胞的形态以六边形为主,鳃丝表皮未观察到黏液细胞。由此推测,青海湖裸鲤两亚种鳃形态的差异与其食性和栖息环境相适应。