Abstract Detail

Physiology

Andreev, Victor [1], Fishbein, Mark [2].

Differential physiological adaptations of Asclepias speciosa and A. syriaca to drought stress.

Asclepias speciosa (western part of the US) and A. syriaca (eastern part of the US) meet and hybridize on the Great Planes on a steep precipitation gradient. The distribution of these species on the gradient implies that A. speciosa is more drought resistant than A. syriaca, and that there is a species-specific suit of adaptive traits related to drought stress. Our goal was to evaluate the physiological differences in drought-related traits between A. speciosa and A. syriaca in a dry-down experiment. We focused on dynamics of stomatal conductance over the course of the experiment, time to wilting, growth rate and biomass accumulation, re-sprouting rate after removing the above ground biomass. In addition, we evaluated interspecific differences in leaf mass per area, trichome density, stomatal density, and root biomass.The experiment demonstrated that A. syriaca is more drought tolerant than A. speciosa. The apparent contradiction of this result with our expectations suggests that A. speciosa prefers more wet microhabitats. We conclude that these species employ different strategies for handling drought stress, and A. syriaca is a drought resistant species, while A. speciosa is its drought avoiding counterpart.

1 - Oklahoma State University, 301 Physical Sciences, 301 Physical Sciences, Stillwater, OK, 74078, United States
2 - Oklahoma State University, Dept Of Plant Biology, Ecology & Evolution, 301 Physical Science, Stillwater, OK, 74078, United States

Keywords:
Asclepias
drought resistance
Local adaptation.

Presentation Type: Poster
Number: PPS003
Abstract ID:705
Candidate for Awards:None