Parallels between drought and flooding: an integrated framework for
plant eco-physiological responses to water stress
Abstract
Drought and flooding occur at opposite ends of the soil moisture
spectrum yet resulting stress responses that occur in plants share many
similarities. Drought limits root water uptake to which plants respond
with stomatal closure and reduced leaf gas exchange. Flooding limits
root metabolism due to soil anoxia, which also limits root water uptake
and leaf gas exchange. As drought and flooding can occur consecutively
in the same system and resulting plant stress responses share similar
mechanisms, a single theoretical framework that integrates plant
responses over a continuum of soil water conditions from drought to
flooding is attractive. Based on a review of recent literature, we
integrated the main plant eco-physiological mechanisms in a single
theoretical model with a focus on plant water transport, plant oxygen
dynamics, and leaf gas exchange. We used the
Soil-Plant-Atmosphere-Continuum model as “backbone” for our
theoretical framework development, and subsequently incorporated
interactions between processes that regulate plant water and oxygen
status, levels of abscisic acid and ethylene hormones and resulting
acclimation strategies in response to drought, waterlogging, and
complete submergence. Our theoretical framework provides a basis for the
development of mathematical models to describe plant responses to the
soil moisture continuum from drought to flooding.