Abstract Detail

Ecophysiology

Flores, Ana I. [1], Barton, Kasey [2].

Trait Variation as Plants Grow Up: Simultaneous Effects of Ontogeny and Phenotypic Plasticity.

Understanding and identifying drivers of trait variation is at the forefront of plant functional ecology, underlying much of the research on phenotypic plasticity in response to biotic and abiotic stressors. As a major source of intraspecific trait variation, the role of phenotypic plasticity has been widely characterized, but few studies consider this across developmental stages, i.e., ontogeny. There is extensive evidence that functional traits vary across ontogeny, reflecting changing environmental conditions and intrinsic constraints, but how genetically regulated ontogenetic trait shifts, and plasticity together drive phenotypic variation in plants, remains difficult to disentangle. To address this, we conducted a greenhouse study to investigate phenotypic plasticity in response to abiotic stress throughout ontogeny, quantifying traits implicated in different resource-use strategies, including leaf economic spectrum traits and physical and chemical defense traits. Specifically, we manipulated light and water availability in a full factorial experiment, measuring traits within treatment groups at the seedling, juvenile, and adult stages, likely to be multifunctional (photosynthesis, stomatal conductance, fluorometry including electron transport rate, non-photochemical quenching and yield, chlorophyll, latex volume, leaf area and leaf mass per area, and prickle density). Trait variation across stages reflects ontogenetic patterns, while shifts in the slope or magnitude of these patterns among treatment groups indicate phenotypic plasticity in ontogenetic trait trajectories. We detected dramatic ontogenetic variation in response to both light and water. The magnitude of plasticity varied among traits, with gas exchange traits demonstrating more plasticity in response to water availability, and leaf morphological traits more responsive to light. Ontogeny was a constraining factor in some traits, limiting plasticity. Expected patterns of trait covariation, sensu leaf economic spectrum, were not observed in all cases indicating different functional strategies for plants through ontogeny along the acquisitive-conservative resource use spectrum. These results reveal the important role of ontogeny in driving plant response to stress and provides insight into the drivers of phenotypic plasticity as plants face a changing environment across ontogeny.

1 - 3087 Puhala Rise, Honolulu, HI, 96822, USA
2 - University Of Hawaii, School Of Life Sciences, 2538 McCarthy Mall , Edmondson Hall, Room 216, Honolulu, HI, 96822, United States

Keywords:
Phenotypic plasticity
Ontogeny
ontogenetic trajectory
leaf traits
Resource allocation
functional traits
spinescence.

Presentation Type: Oral Paper
Number: EPH1005
Abstract ID:945
Candidate for Awards:Physiological Section Best Paper Presentation