scholarly journals Evolutionary response to Quaternary climate aridification and oscillations in north-western China revealed by chloroplast phylogeography of the desert shrubNitraria sphaerocarpa(Nitrariaceae)

2013 ◽  
Vol 109 (4) ◽  
pp. 757-770 ◽  
Author(s):  
Zhihao Su ◽  
Mingli Zhang
2012 ◽  
Vol 60 (1) ◽  
pp. 20 ◽  
Author(s):  
S. M. Ma ◽  
M. L. Zhang ◽  
S. C. Sanderson

We investigated the phylogeography of Gymnocarpos przewalskii Maxim. (Caryophyllaceae), a rare relictual shrub restricted to north-western China, in the context of Quaternary climate oscillations. Three cpDNA regions (psbA–trnH, ycf6–psbM and rpl32–trnL (UAG)) were sequenced for 160 individuals from 16 populations. High genetic diversity (hT = 0.930, hS = 0.425) and a significant phylogeographic structure (NST > GST, P < 0.01) were identified; 31 different cpDNA haplotypes were detected. Phylogenetic analyses showed that the haplotypes were clustered into five clades, consistent with their distributions in the following four geographic regions: the Tarim Basin, Hami Basin, the western Yumen of Gansu Province and an easternmost region, consisting of populations in the Wulate Rear Banner region in Inner Mongolia, the Jinta and Jingyuan regions in Gansu Province and the Zhongwei region in Ningxia. The existence of regional divergence was supported by AMOVA, which revealed that ~63% of variation was due to differences among the four geographic regions. Four independent glacial refugia were inferred, in the western Tarim Basin, Hami Basin, the Liuyuan region in western Gansu and the easternmost region mentioned. Population bottlenecks and postglacial recolonisation were identified in the northern Tarim Basin, western Yumen and the Jinta region in Gansu Province.


Author(s):  
WILLIAM GARDENER

Prince Henri d'Orleans, precluded by French law from serving his country in the profession of arms, had his attention turned early towards exploration. In 1889, accompanied by the experienced traveller Gabriel Bonvalet, he set out from Paris to reach Indo-China overland by way of Central Asia, Tibet and western and south western China. The journey made contributions in the problems of the whereabouts of Lap Nor and the configuration of the then unexplored northern plateau of Tibet; and in botany it produced some species new to science. The party reached Indo-China in 1890. In 1895, having organised an expedition better equipped for topographical survey and for investigations in the fields of natural history and ethnography, Prince Henri set out from Hanoi with the intention of exploring the Mekong through the Chinese province of Yunnan. After proceeding up the left bank of the Salween for a brief part of its course and then alternating between the right and left banks of the Mekong as far up as Tzeku, the party found it advisable to enter Tibet in a north westerly direction through the province of Chamdo and instead crossed the south eastern extremity of the country, the Zayul, by a difficult track which led them to the country of the Hkamti Shans in present day Upper Burma, and thence to India completing a journey of 2000 miles, "1500 of which had been previously untrodden" (Prince Henri). West of the Mekong, the journey established that the Salween, which some geographers had claimed took its rise in or near north western Yunnan, in fact rose well north in Tibet, and that, contrary to previous opinions, the principal headwater of the Irrawaddy rose no further north than latitude 28°30'. Botanical collections were confined to Yunnan, where the tracks permitted mule transport, and they produced a number of species new to science and extended the range of distribution of species already known.


2011 ◽  
Vol 162 (1) ◽  
pp. 201-219 ◽  
Author(s):  
SHU-AN JI ◽  
JESSIE ATTERHOLT ◽  
JINGMAI K. O'CONNOR ◽  
MATTHEW C. LAMANNA ◽  
JERALD D. HARRIS ◽  
...  

2017 ◽  
Vol 163 (3) ◽  
pp. 523-535 ◽  
Author(s):  
Zhengcai Zhang ◽  
Zhibao Dong ◽  
Guangqian Qian ◽  
Guoxi Wu ◽  
Xujia Cui

2013 ◽  
Vol 61 (1) ◽  
pp. 29 ◽  
Author(s):  
Ling-Ping Zhao ◽  
Gao-Lin Wu ◽  
Zhi-Hua Shi

Offspring recruitment is an important part of population dynamics, as well as for plant-community structure and succession. One generality regarding grasses and fire is that clonal grasses tolerate fire extremely well and in most cases reach their maximum production in the immediate post-fire years. One qualification to this statement is that post-fire offspring, recruitment mode is very important. However, respective data are scare in the semiarid perennial steppe. We studied the relative importance of asexual v. sexual recruitment in the post-fire recovery in semiarid steppe on the Loess Plateau of north-western China. We observed differences in regeneration strategy after different times post-fire (burnt in 2008, burnt in 1999, and no fire history for at least 30 years). Results showed that fire significantly increased offspring recruitment numbers, but not species richness. The increase of asexual recruitment after a fire made a major contribution to the increase of total offspring number. Meanwhile, there was no significant difference for the ratio of asexual to sexual recruitment among sites with different times since fire. The asexual to sexual recruitment ratio was significantly different for different species, with some species not recruiting offspring via sexual recruitment. Our results indicated that seedling recruitment contributed little to post-fire recovery of the perennial-steppe community. Lack of sexual recruitment is not related to fire management but to inherent traits of the occurring plants.


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