Dispersal biophysics and adaptive significance of dimorphic diaspores in the annual Aethionema arabicum (Brassicaceae). / Arshad, Waheed; Sperber, Katja; Steinbrecher, Tina; Nichols, Bethany; Jansen, Vincent A. A.; Leubner, Gerhard; Mummenhoff, Klaus.

In: New Phytologist, 03.09.2018.

Research output: Contribution to journalArticle

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Abstract

• Heteromorphic diaspores (fruits and seeds) are an adaptive bet-hedging strategy to cope with spatio-temporally variable environments, particularly to fluctuations in favourable temperatures and to unpredictable precipitation regimes in arid climates.
• We conducted comparative analyses of the biophysical and ecophysiological properties of the two distinct diaspores (mucilaginous seed [M+] vs. indehiscent [IND] fruit) in the dimorphic annual Aethionema arabicum (Brassicaceae), linking fruit biomechanics, dispersal aerodynamics, pericarp-imposed dormancy, diaspore abscisic acid (ABA) content, and phenotypic plasticity of dimorphic diaspore production to its natural habitat and climate.
• Two very contrasting dispersal mechanisms of the Ae. arabicum dimorphic diaspores were revealed. Dehiscence of large fruits leads to the release of M+ seed diaspores, which adhere to substrata via seed coat mucilage, thereby preventing dispersal (anti-telechory). IND fruit diaspores (containing non-mucilaginous seeds) disperse by wind or water currents, promoting dispersal (telechory) over a longer range.
• The pericarp properties confer enhanced dispersal ability and degree of dormancy to the IND fruit morph to support telechory, while the M+ seed morph supports anti-telechory. Combined with the phenotypic plasticity to produce more IND fruit diaspores in colder temperatures, this constitutes a bet-hedging survival strategy to magnify the prevalence in response to selection pressures acting over hilly terrain.
Original languageEnglish
JournalNew Phytologist
StateAccepted/In press - 3 Sep 2018

ID: 30865260