scholarly journals Not so ancient: Misclassification of alpine plants biases the dating of the evolution of alpine biota in the Himalaya-Tibet Orogen

2021 ◽  
Author(s):  
Lars Opgenoorth ◽  
Georg Miehe ◽  
Joachim Schmidt

Ding et al. (Science 2020) proposed that the extant lineages of the alpine flora of the Tibet Himalaya Hengduan region emerged by the early Oligocene. We argue that these results are based on misclassifying high montane taxa as alpine and that their data support alpine habitats only at about 7.5 mio years before present.

2020 ◽  
Author(s):  
Pamela Bhattacharya ◽  
Samrat Mondol ◽  
Gautam Talukdar ◽  
Gopal Singh Rawat

AbstractSoil heterotrophic respiration-driven CO2 emissions, its impact on global warming and the mechanistic roles of soil bacterial communities in this process have been an area of active research. However, our knowledge regarding the effects of environmental changes on soil bacterial communities is limited. To this end, the climate-sensitive high-altitude alpine ecosystems offer ideal opportunities to investigate relationship between climate change and bacterial communities. While data from several high-altitude mountain regions suggest that local environment factors and geological patterns govern bacterial communities, no information is available from the Himalaya. Here we provide baseline information on seasonal soil bacterial community diversity and composition along a 3200-4000 m elevation gradient covering four alpine habitats (subalpine forest, alpine scrub, alpine meadow and moraine) in Gangotri National Park, western Himalaya. Bacterial metabarcoding data from 36 field-collected samples showed no elevation trend in the bacterial richness and a non-monotonous decrease in their diversity. Further, their community diversity and composition varied significantly among habitats along elevation but were stable seasonally within each habitat. The richness was primarily influenced by soil inorganic carbon (SOC) and total nitrogen (TN), whereas temperature, SOC and TN affected diversity and composition patterns. Given the importance of the Himalaya in the context of global carbon cycle this information will help in accurate modeling of climate adaptation scenarios of bacterial niches and their downstream impacts towards climate warming.


Alpine Botany ◽  
2020 ◽  
Vol 130 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Sergey Rosbakh ◽  
Vera Margreiter ◽  
Bernardica Jelcic

Abstract In contrast to adult plants, little is known about the frost-tolerance of seedlings of alpine species, despite the fact that frost has been considered as one of the main factors limiting plant recruitment in high elevation. Here we report the results of a comparative study on seedling frost-tolerance of nine congeneric species pairs with lowland (0–900 m a.s.l.) and alpine (1800–2700 m a.s.l.) distribution. Similarly to adult alpine plants, we expected seedlings of alpine species to be more frost-tolerant than their lowland counterparts. Frost-tolerance was estimated under laboratory conditions by exposing seedlings to frost events from − 1 to − 9 °C, calculated as the temperature at which 50% of the seedlings were lethally damaged by frost (LT50). The LT50 values varied between − 1.95 and − 6.11 °C suggesting that seedling of all tested species could potentially survive mild and/or short frosts, but might be lethally damaged by severe and/or continuous frost events. The LT50 values for lowland and alpine species did not differ statistically and were on average − 3.96 ± 0.18 °C and − 4.16 ± 0.43 °C, respectively. These findings did not confirm our hypothesis that seedlings of alpine species have higher frost-tolerance than seedlings of lowland species. Four possible reasons could explain this pattern. They include (1) comparable levels of negative-stress in both lowland and alpine habitats, (2) opportunistic seed germination strategy in alpine plants, (3) peculiarities of our experimental set up and (4) potentially stronger effects of drought on alpine seedling survival than frost.


Author(s):  
George C. Ruben ◽  
Kenneth A. Marx

In vitro collapse of DNA by trivalent cations like spermidine produces torus (donut) shaped DNA structures thought to have a DNA organization similar to certain double stranded DNA bacteriophage and viruses. This has prompted our studies of these structures using freeze-etch low Pt-C metal (9Å) replica TEM. With a variety of DNAs the TEM and biochemical data support a circumferential DNA winding model for hydrated DNA torus organization. Since toruses are almost invariably oriented nearly horizontal to the ice surface one of the most accessible parameters of a torus population is annulus (ring) thickness. We have tabulated this parameter for populations of both nicked, circular (Fig. 1: n=63) and linear (n=40: data not shown) ϕX-174 DNA toruses. In both cases, as can be noted in Fig. 1, there appears to be a compact grouping of toruses possessing smaller dimensions separated from a dispersed population possessing considerably larger dimensions.


2006 ◽  
Vol 40 (3) ◽  
pp. 39
Author(s):  
SHARON WORCESTER

2012 ◽  
Vol 43 (2) ◽  
pp. 1-9
Author(s):  
MIRIAM E. TUCKER
Keyword(s):  

2009 ◽  
Vol 2 (8) ◽  
pp. 8
Author(s):  
BRUCE JANCIN
Keyword(s):  

2012 ◽  
Vol 42 (14) ◽  
pp. 28
Author(s):  
SUSAN LONDON
Keyword(s):  

2014 ◽  
Vol 0 (3) ◽  
Author(s):  
Viktor K. Partas ◽  
Alona Yu. Pavlenko

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