TY  - JOUR
A1  - Woutersen, Amber
A1  - Jardine, Phillip E.
A1  - Giovanni Bogota-Angel, Raul
A1  - Zhang, Hong-Xiang
A1  - Silvestro, Daniele
A1  - Antonelli, Alexandre
A1  - Gogna, Elena
A1  - Erkens, Roy H. J.
A1  - Gosling, William D.
A1  - Dupont-Nivet, Guillaume
A1  - Hoorn, Carina
T1  - A novel approach to study the morphology and chemistry of pollen in a phylogenetic context, applied to the halophytic taxon Nitraria L.(Nitrariaceae)
JF  - PeerJ
N2  - Nitraria is a halophytic taxon (i.e., adapted to saline environments) that belongs to the plant family Nitrariaceae and is distributed from the Mediterranean, across Asia into the south-eastern tip of Australia. This taxon is thought to have originated in Asia during the Paleogene (66-23 Ma), alongside the proto-Paratethys epicontinental sea. The evolutionary history of Nitraria might hold important clues on the links between climatic and biotic evolution but limited taxonomic documentation of this taxon has thus far hindered this line of research. Here we investigate if the pollen morphology and the chemical composition of the pollen wall are informative of the evolutionary history of Nitraria and could explain if origination along the proto-Paratethys and dispersal to the Tibetan Plateau was simultaneous or a secondary process. To answer these questions, we applied a novel approach consisting of a combination of Fourier Transform Infrared spectroscopy (FTIR), to determine the chemical composition of the pollen wall, and pollen morphological analyses using Light Microscopy (LM) and Scanning Electron Microscopy (SEM). We analysed our data using ordinations (principal components analysis and non-metric multidimensional scaling), and directly mapped it on the Nitrariaceae phylogeny to produce a phylomorphospace and a phylochemospace. Our LM, SEM and FTIR analyses show clear morphological and chemical differences between the sister groups Peganum and Nitraria. Differences in the morphological and chemical characteristics of highland species (Nitraria schoberi, N. sphaerocarpa, N. sibirica and N. tangutorum) and lowland species (Nitraria billardierei and N. retusa) are very subtle, with phylogenetic history appearing to be a more important control on Nitraria pollen than local environmental conditions. Our approach shows a compelling consistency between the chemical and morphological characteristics of the eight studied Nitrariaceae species, and these traits are in agreement with the phylogenetic tree. Taken together, this demonstrates how novel methods for studying fossil pollen can facilitate the evolutionary investigation of living and extinct taxa, and the environments they represent.
KW  - FTIR
KW  - LM
KW  - SEM
KW  - Paratethys
KW  - Tibet
KW  - Sporopollenin
KW  - Mediterranean
KW  - Steppe-desert
KW  - Australia
KW  - Palynology
Y1  - 2018
U6  - https://doi.org/10.7717/peerj.5055
SN  - 2167-8359
VL  - 6
PB  - PeerJ Inc.
CY  - London
ER  - 
TY  - JOUR
A1  - Barbolini, Natasha
A1  - Woutersen, Amber
A1  - Dupont-Nivet, Guillaume
A1  - Silvestro, Daniele
A1  - Tardif-Becquet, Delphine
A1  - Coster, Pauline M. C.
A1  - Meijer, Niels
A1  - Chang, Cun
A1  - Zhang, Hou-Xi
A1  - Licht, Alexis
A1  - Rydin, Catarina
A1  - Koutsodendris, Andreas
A1  - Han, Fang
A1  - Rohrmann, Alexander
A1  - Liu, Xiang-Jun
A1  - Zhang, Y.
A1  - Donnadieu, Yannick
A1  - Fluteau, Frederic
A1  - Ladant, Jean-Baptiste
A1  - Le Hir, Guillaume
A1  - Hoorn, M. Carina
T1  - Cenozoic evolution of the steppe-desert biome in Central Asia
JF  - Science Advances
N2  - The origins and development of the arid and highly seasonal steppe-desert biome in Central Asia, the largest of its kind in the world, remain largely unconstrained by existing records. It is unclear how Cenozoic climatic, geological, and biological forces, acting at diverse spatial and temporal scales, shaped Central Asian ecosystems through time. Our synthesis shows that the Central Asian steppe-desert has existed since at least Eocene times but experienced no less than two regime shifts, one at the Eocene-Oligocene Transition and one in the mid-Miocene. These shifts separated three successive "stable states," each characterized by unique floral and faunal structures. Past responses to disturbance in the Asian steppe-desert imply that modern ecosystems are unlikely to recover their present structures and diversity if forced into a new regime. This is of concern for Asian steppes today, which are being modified for human use and lost to desertification at unprecedented rates.
Y1  - 2020
U6  - https://doi.org/10.1126/sciadv.abb8227
SN  - 2375-2548
VL  - 6
IS  - 41
PB  - American Association for the Advancement of Science
CY  - Washington
ER  -