Trait coordination and structural variation in Amborella trichopoda

Finding that Amborella trichopoda is sister to the rest of the angiosperms has raised the question of whether it shares certain key functional trait characteristics and plastic responses apparently widespread within the angiosperms at large. With this in mind, Trueba et al. tested the hypothesis that local canopy openness induces plastic responses in Amborella in a recent study published in AoB PLANTS. The authors provide evidence of intraspecific coordination between leaf and stem economic spectra in this key species. Moreover, by presenting the first architectural and biomechanical characterization of Amborella, their study offers new insights for the understanding of the early sequences of angiosperm form evolution.

Illustration of ontogenetic architectural stages of Amborella trichopoda , and architectural variability under closed or open canopies.
Illustration of ontogenetic architectural stages of Amborella trichopoda, and architectural variability under closed or open canopies. (A) Seedling and unbranched young plant 6 months after germination (stage 1). (B) 1-year-old plant (stage 2). (C) 1.5-year-old plant with a rooted ‘pseudo-rhizome’ (stage 2). (D) Around 6-year-old plant (stage 3). (E) >10-year-old plant growing under a closed canopy (stage 4). (F) >10 year-old-plant growing under open canopy (stage 4). Only one sequence of the successive modules of stage 4 individuals is represented. Abbreviations: adv, adventitious root; co, collar zone. Thick lines represent structural axes, thin lines represent lateral branches, arrowhead lines represent delayed relays, crosses are dead apices, circles are inflorescences, and gray shadings indicate successive architectural modules.

Reference

Trueba, S., Isnard, S., Barthélémy, D., & Olson, M. E. (2016). Trait coordination, mechanical behaviour and growth form plasticity of Amborella trichopoda under variation in canopy openness. AoB Plants, 8, plw068. http://dx.doi.org/10.1093/aobpla/plw068