The Natural History of Model Organisms: Planting molecular functions in an ecological context with Arabidopsis thaliana
Figures
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Life cycle of Arabidopsis thaliana.
(A) A. thaliana of the accession Columbia (Col) at different stages of its life cycle, from seed (bottom left) to seedling (11 days), to vegetative growth (39 days), and to reproductive growth (45 days). Photographs of (B) a flower, (C) a pollen grain (scanning electron micrograph), and (D) mature siliques (seed pods; left: closed; right: open with a few remaining unshattered seeds) at higher magnification. Image credits: B and C, Maria Bernal and Peter Huijser; other photographs, Ines Kubigsteltig and Klaus Hagemann.
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A. thaliana and a subset of species from its sister clade.
From left to right: A. thaliana (Col), A. halleri (ssp. halleri; individual Lan5, Langelsheim, Harz, Germany), A. lyrata (ssp. lyrata; selfing accession Great Lakes, North America), and A. croatica (Baške Oštarje/Ljubičko Brdo, Croatia). A. thaliana was grown from seed to early reproductive stage, and the other species were propagated vegetatively and grown for 3–6 months. The individuals shown here do not reflect the large within-species morphological diversity, particularly in leaf shape, among different accessions of A. halleri and A. lyrata. Image credit: Ute Krämer and Klaus Hagemann.
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Map of A. thaliana worldwide distribution.
Areas colored in red correspond to the continuous distribution of A. thaliana; red circles mark additional sites. This map is based on a partial map kindly provided by Matthias Hoffmann (personal communication, November 2014), with manual additions to the southern hemisphere (Bresinsky et al., 2008). Image credit: Ute Krämer and Klaus Hagemann.
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The simple anatomy of A. thaliana roots.
Longitudinal (left) and transverse (right) confocal sections of A. thaliana roots. Green fluorescence highlights the plasma membrane of the pericycle cells of an A. thaliana hma2hma4 double mutant line (Sinclair et al., 2007) (accession Wassilewskija). Red fluorescence of propidium iodide (PI) as a stain is overlaid to visualize cell walls. The root cell layers (consecutive outward to inward) are: epidermis (e), cortex (c), endodermis (n) and pericycle (p). Note that the Casparian Strip surrounding the endodermis cells forms an apoplastic diffusion barrier (Roppolo et al., 2011) that blocks the movement of PI further inward. Image credit: Ute Krämer and Scott A. Sinclair.