Abstract Detail

Ecophysiology

Carvajal, Danny E. [1], Loayza, Andrea [2], Squeo, Francisco [3].

Contrasting responses to water-deficit among Encelia canescens populations distributed along an aridity gradient.

Drought is the most limiting factor for plant growth and recruitment in arid environments. For widespread species, however, plant responses to drought can vary across populations because environmental conditions vary along the range of the species. Here, we assessed whether plants of Encelia canescens from different populations along an aridity gradient in the Atacama Desert respond differently to water deficit conditions. We conducted a common-garden experiment using plants grown from seeds from three populations distributed along an aridity gradient to test for differences in relative growth rate (RGR), biomass, root to shoot ratio, and photosynthesis between watered and water-deficit plants. Additionally, we examined the relationship between root to shoot ratio with RGR and total plant biomass along the gradient. Water deficit affected root to shoot ratio, biomass, and RGR, but not photosynthesis. Populations varied in RGR and biomass; plants from the most arid population had higher RGRs, but lower biomass than those from the least arid population. In watered conditions, root to shoot ratio did not vary with RGR or biomass. Conversely, with the water deficit, root to shoot ratio was negatively and positively related to biomass and RGR, respectively. We concluded that response to water deficit differed among E. canescens populations; plants from the lowest rainfall environment adjusted root to shoot ratio, which may have allowed for equal biomass production across treatments. In contrast, plants from the wettest population did not adjust root to shoot ratio, but were reduced in biomass. These morphological and physiological changes to water availability showed that populations can use different strategies to cope with water deficit.

1 - Universidad de La Serena, Biologia, Benavente 980, La Serena, 1720170
2 - Universidad de La Serena, Biology, Raul Bitran 1305, Campus Colina El Pino, La Serena, Coquimbo, 1721377, Chile
3 - Universidad de La Serena, Biologia, La Serena

Keywords:
relative growth rate
Aridity gradient
Atacama Desert
root to shoot ratio
photosynthesis.

Presentation Type: Poster
Session: P, Ecophysiology Poster Session
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEP011
Abstract ID:727
Candidate for Awards:None