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72.
Contrasting responses to Pleistocene climate changes: a case study of two sister species Allium cyathophorum and A. spicata (Amaryllidaceae) distributed in the eastern and western Qinghai–Tibet Plateau
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Xinyu Wang Yuanshuo Li Qianlong Liang Lei Zhang Qian Wang Huan Hu Yongshuai Sun 《Ecology and evolution》2015,5(7):1513-1524
It has been hypothesized that species occurring in the eastern and the western Qinghai–Tibet Plateau (QTP) responded differently to climate changes during the Pleistocene. Here, we test this hypothesis by phylogeographic analysis of two sister species, Allium cyathophorum and A. spicata. We sequenced two chloroplast DNA (cpDNA) fragments (accD‐psaI and the rpl16 intron) of 150 individuals, and the nuclear (ITS) region of 114 individuals, from 19 populations throughout the distributional ranges of these species. The divergence between the two species was dated at 779 ‐ 714 thousand years before the present and was likely initiated by the most major glaciation in the QTP. Analysis of chlorotype diversity showed that A. spicata, the species occurring in the western QTP, contains much lower genetic diversity (0.25) than A. cyathophorum (0.93), which is distributed in the eastern QTP. Moreover, multiple independent tests suggested that the A. spicata population had expanded recently, while no such expansion was detected in A. cyathophorum, indicating a contrasting pattern of responses to Pleistocene climate changes. These findings highlight the importance of geographical topography in determining how species responded to the climate changes that took place in the QTP during the Pleistocene. 相似文献
73.
74.
Above- and belowground biomass allocation not only influences growth of individual plants, but also influences vegetation
structures and functions, and consequently impacts soil carbon input as well as terrestrial ecosystem carbon cycling. However,
due to sampling difficulties, a considerable amount of uncertainty remains about the root: shoot ratio (R/S), a key parameter
for models of terrestrial ecosystem carbon cycling. We investigated biomass allocation patterns across a broad spatial scale.
We collected data on individual plant biomass and systematically sampled along a transect across the temperate grasslands
in Inner Mongolia as well as in the alpine grasslands on the Tibetan Plateau. Our results indicated that the median of R/S
for herbaceous species was 0.78 in China’s grasslands as a whole. R/S was significantly higher in temperate grasslands than
in alpine grasslands (0.84 vs. 0.65). The slope of the allometric relationship between above- and belowground biomass was
steeper for temperate grasslands than for alpine. Our results did not support the hypothesis that aboveground biomass scales
isometrically with belowground biomass. The R/S in China’s grasslands was not significantly correlated with mean annual temperature
(MAT) or mean annual precipitation (MAP). Moreover, comparisons of our results with previous findings indicated a large difference
between R/S data from individual plants and communities. This might be mainly caused by the underestimation of R/S at the
individual level as a result of an inevitable loss of fine roots and the overestimation of R/S in community-level surveys
due to grazing and difficulties in identifying dead roots. Our findings suggest that root biomass in grasslands tended to
have been overestimated in previous reports of R/S. 相似文献
75.
Adams V Miller S Craig S Sonam Nyima Droyoung Le PV Varner M 《Culture, medicine and psychiatry》2007,31(4):445-472
Procedures of Informed Consent are considered a high priority for international biomedical research. However, informed consent protocols are not necessarily transferable across cultural, national or ethnic groups. Recent debates identify the need for balancing ethical universals with practical and local conditions and paying attention to questions of cultural competence when it comes to the Informed Consent process for clinical biomedical research. This article reports on the results of a two-year effort to establish a culturally appropriate Informed Consent process for biomedical research in the Tibet Autonomous Region in the People's Republic of China. A team of Tibetan and American researchers, physicians, health professionals and medical anthropologists conducted the research. The Informed Consent was specifically for undertaking a triple-blind, double placebo-controlled randomized clinical trial of a Tibetan medicine compared with Misoprostol for reducing postpartum blood loss. The findings suggest greater need for flexibility and cooperation in establishing Informed Consent protocols across cultures and nations. 相似文献
76.
BRET A. COLLIER DUSTIN A. JONES JODY N. SCHAAP CHARLES J. RANDEL III BEAU J. WILLSEY RAY AGUIRRE T. WAYNE SCHWERTNER NOVA J. SILVY MARKUS J. PETERSON 《The Journal of wildlife management》2007,71(1):82-86
Abstract: The southeastern portion of the Edwards Plateau of Texas, historically a stronghold of Rio Grande wild turkeys (Meleagris gallopavo intermedia), has seen a decline in turkey numbers since the 1970s. Because adult and juvenile survival are key parameters affecting turkey population dynamics, we used radiotagged individuals to compare Rio Grande wild turkey survival in areas of suspected decline versus stable portions of the Edwards Plateau during 2001–2003. Reproductive period (breeding or nonbreeding) had an impact on survival, but differences in age, sex, or region did not influence survival. Model averaged estimates of monthly survival were 0.97 (SE = 0.005) for nonbreeding periods and 0.96 (SE = 0.007) for breeding periods. Our results indicate juvenile and adult survival in the declining areas was similar to survival in the stable areas of the Edwards Plateau. This suggests causes of the decline might be associated with differences during other life-history stages, such as nest success or poult survival, although we cannot rule out the possibility juvenile or adult survival contributed to the decline in the past. This situation demonstrates why wildlife managers should be cognizant of the implications of initiating long-term monitoring programs after changes in population status occur, rather than initiating them in expectation of such changes. 相似文献
77.
鄂尔多斯高原蒙古族食用野生植物传统知识的研究 总被引:2,自引:0,他引:2
运用民族植物学"5W+1H"提问法,结合访谈方法和野外调查进行编目,研究了鄂尔多斯高原蒙古族食用野生植物的传统知识。结果:1)鄂尔多斯蒙古族传统食用植物22科32属50种,其中野生粮用植物14种、野生蔬菜13种、野果植物18种、野果酒植物3种、野生调味植物5种、野生薰净植物2种、催化乳制品植物1种。2)鄂尔多斯蒙古族野生食用植物传统知识包括7个方面,其中用植物薰净和消毒奶食器具的传统知识、用冷蒿催化加速油脂成分从奶子中分离的传统知识是蒙古族植物饮食文化的创新。具有鲜明的民族特色、简单、快捷的"果实+奶食"酿果酒文化,能够说明蒙古族祖先在生产实践中掌握了开发和利用植物资源的更高水平的技术和文化。食用芨芨草颖果、选用中间锦鸡儿韧皮部和白沙蒿的果实做面食粘合剂的传统知识是区域特色的文化。3)因生态环境条件的不同,山区、沙区、盐渍区和丘陵区蒙古族牧民的传统食用植物知识表现出多样性,反映了生态环境条件的多样性。4)鄂尔多斯蒙古族野生食用植物传统知识丰富了蒙古族饮食文化,对蒙古族文化的发展做出了贡献。开展搜集、研究、保护和科学分析鄂尔多斯蒙古族植物传统知识的工作,将对社会经济的可持续发展产生十分积极的直接影响。 相似文献
78.
NADH dehydrogenase (complex I) couples the oxidation of NADH for the reduction of ubiquinone with the generation of a proton gradient that can be used for the synthesis of ATP. We have found a missense mutation in the MT-ND5 subunit of NADH dehydrogenase in the Tibet chicken breed. In the present study, the mitochondrial respiratory control ratio (RCR) and NADH dehydrogenase activity in Tibet chicken embryonic brain with different genotypes were measured. Significant differences between animals carrying mitochondria with the EF493865.1:m.1627A vs. EF493865.1:m.1627C alleles were observed for RCR and enzyme activity. 相似文献
79.
Mitochondrial and chloroplast phylogeography of Picea crassifolia Kom. (Pinaceae) in the Qinghai-Tibetan Plateau and adjacent highlands 总被引:3,自引:0,他引:3
The disjunct distribution of forests in the Qinghai-Tibetan Plateau (QTP) and adjacent Helan Shan and Daqing Shan highlands provides an excellent model to examine vegetation shifts, glacial refugia and gene flow of key species in this complex landscape region in response to past climatic oscillations and human disturbance. In this study, we examined maternally inherited mitochondrial DNA (nad1 intron b/c and nad5 intron 1) and paternally inherited chloroplast DNA (trnC-trnD) sequence variation within a dominant forest species, Picea crassifolia Kom. We recovered nine mitotypes and two chlorotypes in a survey of 442 individuals from 32 populations sampled throughout the species' range. Significant mitochondrial DNA population subdivision was detected (G(ST) = 0.512; N(ST) = 0.679), suggesting low levels of recurrent gene flow through seeds among populations and significant phylogeographical structure (N(ST) > GST, P < 0.05). Plateau haplotypes differed in sequence from those in the adjacent highlands, suggesting a long period of allopatric fragmentation between the species in the two regions and the presence of independent refugia in each region during Quaternary glaciations. On the QTP platform, all but one of the disjunct populations surveyed were fixed for the same mitotype, while most populations at the plateau edge contained more than one haplotype with the mitotype that was fixed in plateau platform populations always present at high frequency. This distribution pattern suggests that present-day disjunct populations on the QTP platform experienced a common recolonization history. The same phylogeographical pattern, however, was not detected for paternally inherited chloroplast DNA haplotypes. Two chlorotypes were distributed throughout the range of the species with little geographical population differentiation (G(ST) = N(ST) = 0.093). This provides evidence for highly efficient pollen-mediated gene flow among isolated forest patches, both within and between the QTP and adjacent highland populations. A lack of isolation to pollen-mediated gene flow between forests on the QTP and adjacent highlands is surprising given that the Tengger Desert has been a geographical barrier between these two regions for approximately the last 1.8 million years. 相似文献
80.
西地中海地区早白垩世阿普特期"costata亚带"(O’Dogherty,1994)的带化石"Turbocapsula costata( Wu)",源自藏南赛诺曼期冲堆组的Tricapsula costata Wu。2002年,Matsuoka等把藏南下鲁硅岩层位最高的放射虫带与"costata亚带"对比,称为"Turbocapsulacostata"带,并认为冲堆组时代也应为阿普特期。但西地中海区的"Turbocapsula costata( Wu)"和冲堆组的Tricapsula costata Wu,虽然壳体外形相似,但壳体结构却有重要差别,不是相同属种。前者种名和相应的化石带名都需重新命名。下鲁硅岩的"Turbocapsula costata(Wu)",据图版所示特征,应为Tricapsula costata。下鲁硅岩顶部的时代为晚白垩世赛诺曼期。 相似文献