Plastic bet-hedging in an amphicarpic annual: an integrated strategy under variable conditions |
| |
Authors: | Asaf Sadeh Hagai Guterman Mordechai Gersani Ofer Ovadia |
| |
Institution: | (1) Department of Life Sciences, Ben-Gurion University in the Negev, Beer Sheva, 84105, Israel |
| |
Abstract: | Amphicarpy is a form of diversified bet-hedging expressed mostly in annual plants, where two types of offspring are produced
with two distinct ecological roles: long-range aerial dispersers and highly competitive subterranean, sedentary fruit. Emex spinosa is a semi-arid, amphicarpic annual, inhabiting habitats with different levels of environmental variation. We tested the hypothesis
that, in E. spinosa, bet-hedging may be “fine-tuned” by plasticity in the phenotype ratio (aerial/subterranean fruit mass) as a function of environmental
conditions. We conducted a greenhouse experiment, manipulating nutrient availability and intraspecific density, to determine
the pattern of ratio shifts. In order to determine whether the integrated strategy is an adaptation to variable habitats,
a similar common garden experiment was conducted, comparing two natural populations differing in environmental variability.
The offspring ratio shifted in response to both nutrient availability and plant density. In pots containing single plants
the ratio increased steeply with nutrient availability, while in pots containing eight plants a more moderate increase occurred.
These shifts were the result of plasticity in allocation to both achene types, as well as ontogenetic effects on aerial achene
production. The degree of response increased with the heterogeneity of the habitat of origin. We found evidence for an adaptive
integrated strategy, with bet-hedging “fine-tuned” by phenotypic plasticity. Strenuous conditions tended to shift the offspring
ratio towards securing subterranean reproductive success, while favorable conditions resulted in a shift towards dispersible
achenes.
The authors Asaf Sadeh and Hagai Guterman contributed equally to this study. |
| |
Keywords: | Bet-hedging Seed dispersal Emex spinosa Integrated strategies Life history Phenotypic plasticity Sibling competition Variable environments |
本文献已被 SpringerLink 等数据库收录! |
|