Skip to Main Content
Role of aquaporin activity in regulating deep and shallow root hydraulic conductance during extreme droughtAuthor(s): Daniel M. Johnson; Mark E. Sherrard; Jean-Christophe Domec; Robert B. Jackson
Publication Series: Scientific Journal (JRNL)
Station: Pacific Northwest Research Station
Download Publication (0 B)
DescriptionKey message Deep root hydraulic conductance is upregulated during severe drought and is associated with upregulation in aquaporin activity. Abstract In 2011, Texas experienced the worst single-year drought in its recorded history and, based on tree-ring data, likely itsworst in the pastmillennium. In the Edwards Plateau of Texas, rainfall was 58 % lower and the mean daily maximum temperatures were[5 C higher than long-term means in June through September, resulting in extensive tree mortality. To better understand the balance of deep and shallow root functioning for water supply, wemeasured root hydraulic conductance (KR) in deep (*20 m) and shallow (5–10 cm) roots of Quercus fusiformis at four time points in the field in 2011. Deep roots of Q. fusiformis obtained water from a perennial underground (18–20 m) stream that was present even during the drought.As the drought progressed, deep root KR increased 2.6-fold from early season values and shallow root KR decreased by 50 % between April and September. Inhibitor studies revealed that aquaporin contribution to KR increased in deep roots and decreased in shallow roots as the drought progressed. Deep root aquaporin activity was upregulated during peak drought, likely driven by increased summer evaporative demand and the need to compensate for declining shallow root KR. A whole-tree hydraulic transport model predicted that trees with greater proportions of deep roots would have as much as five times greater transpiration during drought periods and could sustain transpiration during droughts without experiencing total hydraulic failure. Our results suggest that trees shift their dependence on deep roots versus shallow roots during drought periods, and that upregulation of aquaporin activity accounts for at least part of this increase.
- Visit PNW's Publication Request Page to request a hard copy of this publication.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationJohnson, Daniel M.; Sherrard, Mark E.; Domec, Jean-Christophe; Jackson, Robert B. 2014. Role of aquaporin activity in regulating deep and shallow root hydraulic conductance during extreme drought. Trees. 28(5): 1323-1331.
KeywordsCaves, Cavitation, Climate change, Embolism, , Water potential
- Control of live oak decline in Texas with Lignasan and Arbotech
- Physiological, anatomical, and ecological characteristics of southern live oak
- Live Oaks, New Hosts for Odontocynips Nebulosa Kieffer (Hymenoptera: Cynipidae) in North America
XML: View XML