Regulation of root water uptake under abiotic stress conditions

Abstract

A common effect of several abiotic stresses is to cause tissue dehydration. Such dehydration is caused by the imbalance between root water uptake and leaf transpiration. Under some specific stress conditions, regulation of root water uptake is more crucial to overcome stress injury than regulation of leaf transpiration. This review first describes present knowledge about how water is taken up by roots and then discusses how specific stress situations such as drought, salinity, low temperature, and flooding modify root water uptake. The rate of root water uptake of a given plant is the result of its root hydraulic characteristics, which are ultimately regulated by aquaporin activity and, to some extent, by suberin deposition. Present knowledge about the effects of different stresses on these features is also summarized. Finally, current findings regarding how molecular signals such as the plant hormones abscisic acid, ethylene, and salicylic acid, and how reactive oxygen species may modulate the final response of root water uptake under stress conditions are discussed.

The integration of activity in saline environments: problems and perspectives

“…The bulk of this work has been done using A. thaliana and short-term shock treatments. As reviewed recently by Aroca et al (2012), typically, but not universally, PIP and TIP transcript levels decrease upon shock treatment with salt or drought and recover over a period of days as plants acclimate to their new conditions. The decline in the associated proteins does not, however, simply reflect degradation, but re-localisation to intracellular structures (Boursiac et al 2005).…”

Seed imbibition and germination of Plathymenia reticulata Benth. (Fabaceae) affected by mercury: possible role of aquaporins

“…Those are intrinsic proteins with six trans-membrane domains and, among other functions, they facilitate water transport in biomembrane systems (Aroca et al 2012).…”

“…Under physiological conditions, it interacts with the thiol groups of cysteine residues, oxidizing them and reversibly interrupting the activity of these proteins (Aroca et al 2012). Because of its great efficiency in blocking the activity of aquaporins (Przedpelska-Wasowicz & Wierzbicka 2011), mercury chloride (HgCl 2 ) has been frequently used as a tool to study the action of these proteins in water transport at various stages of plant development.…”

Rapid changes in root hydraulic conductivity and aquaporin expression in rice (Oryza sativaL.) in response to shoot removal – xylem tension as a possible signal

“…How this fine-tuning between root water supply and shoot water demand is achieved is not known, but root aquaporins (AQPs) provide an ideal target for such a regulation. Root AQPs have been shown repeatedly to be involved in the regulation of root hydraulic properties (for reviews, see Aroca et al, 2012;Chaumont and Tyerman, 2014;Li et al, 2014).…”

“…This contribution varies with species, time of day and environmental conditions (e.g. Frensch and Steudle, 1989;Zhu and Steudle, 1991;Steudle and Peterson, 1998;Steudle, 2000;Bramley et al, 2009;Fricke, 2010, 2011;Aroca et al, 2012). There is increasing evidence which points to a role for AQPs in also regulating the root hydraulic response to rather sudden changes in shoot transpirational water loss or to 'catastrophic' events such as injury and removal of the shoot (Levin et al, 2009;Almeida-Rodriguez et al, 2011;Sakurai-Ishikawa et al, 2011;Vandeleur et al, 2014).…”