A stomatal control model based on optimization of carbon gain versus hydraulic risk predicts aspen sapling responses to drought.
New Phytol
; 220(3): 836-850, 2018 11.
Article
in En
| MEDLINE
| ID: mdl-29998567
ABSTRACT
Empirical models of plant drought responses rely on parameters that are difficult to specify a priori. We test a trait- and process-based model to predict environmental responses from an optimization of carbon gain vs hydraulic risk. We applied four drought treatments to aspen (Populus tremuloides) saplings in a research garden. First we tested the optimization algorithm by using predawn xylem pressure as an input. We then tested the full model which calculates root-zone water budget and xylem pressure hourly throughout the growing season. The optimization algorithm performed well when run from measured predawn pressures. The per cent mean absolute error (MAE) averaged 27.7% for midday xylem pressure, transpiration, net assimilation, leaf temperature, sapflow, diffusive conductance and soil-canopy hydraulic conductance. Average MAE was 31.2% for the same observations when the full model was run from irrigation and rain data. Saplings that died were projected to exceed 85% loss in soil-canopy hydraulic conductance, whereas surviving plants never reached this threshold. The model fit was equivalent to that of an empirical model, but with the advantage that all inputs are specific traits. Prediction is empowered because knowing these traits allows knowing the response to climatic stress.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Carbon
/
Water
/
Populus
/
Plant Stomata
/
Droughts
/
Models, Biological
Type of study:
Etiology_studies
/
Prognostic_studies
/
Risk_factors_studies
Language:
En
Journal:
New Phytol
Journal subject:
BOTANICA
Year:
2018
Type:
Article
Affiliation country:
United States