Abstract Detail

Ecology

Carlson, Jane [1], Akman, Melis [2], Latimer, Andrew [3].

Intraspecific divergence in plasticity, gene expression, and functional traits along steep environmental gradients in South Africa.

Under rapidly changing climates, each species' ability to persist in place will at least initially depend on its capacity to adjust via plasticity. Some plant species are likely to respond effectively, but even within species, this plastic ability will vary. In the mountainous Cape Floristic Region (CFR) of South Africa, intraspecific variation in plasticity may well be common, because conspecifics often experience distinct climatic conditions, and geography can limit gene flow. As such, evolution may produce populations with high or low plasticity, which would have a strong impact on extinction risk under forecasted climate warming and aridification. Theory suggests that populations having evolved under low environmental heterogeneity and/or colder, harsher environments will exhibit decreased capacity for plasticity. We experimentally tested these hypotheses using the evergreen shrub Protea repens, which has a distribution spanning much of the CFR. We collected seeds from 8 climatically-distinct wild populations and grew them for 5-months in a greenhouse. We estimated the capacity for plasticity in each population by subjecting maternal siblings to either regular watering or 12 days of drought and then comparing phenotypic values between treatments at 6 and 12 days. Phenotypic measurements included stomatal conductance, functional leaf traits, stem pigmentation, growth, and carbohydrate storage above and belowground. We also measured plasticity in gene expression, one of the rawest, most rapid forms of plasticity. Our results provided some support for the cold/harsh hypothesis, in that plants sourced from higher altitudes had lower plasticity for two variables: growth rate and a co-expressed gene network involving heat shock proteins. For two additional gene networks, however, plasticity was lowest in plants sourced from either low or intermediate elevations. Together, these results suggest that P. repens populations in cold, high elevation sites are characterized by low plasticity in growth and heat stress response, even if they have relatively high plasticity by other metrics. By lacking certain types of plasticity, high elevation plants may be particularly threatened by climate change in the region, thus highlighting the urgent need to account for differential plasticity when assessing species vulnerability in future climate scenarios.

1 - Nicholls State University, P.O. Box 2021, Thibodaux, CT, 70310, USA
2 - UC Davis, Plant And Environmental Sciences, One Shields Ave., DAVIS, CA, 95616, USA
3 - UC Davis, Plant Sciences, One Shields Ave, Davis, CA, 95616, USA

Keywords:
Plasticity
Phenotypic traits
Cape Floristic Region
adaptation
climate change.

Presentation Type: Oral Paper
Session: 14, Ecology Section: Plant Functional Traits and Responses
Location: 201/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 3:00 PM
Number: 14005
Abstract ID:580
Candidate for Awards:None