Plant and Soil

, Volume 277, Issue 1, pp 277–284

Wheat Plant Hydraulic Properties Under Prolonged Experimental Drought: Stronger Decline in Root-system Conductance than in Leaf Area

Article

DOI: 10.1007/s11104-005-7493-5

Cite this article as:
Trillo, N. & Fernández, R.J. Plant Soil (2005) 277: 277. doi:10.1007/s11104-005-7493-5

Abstract

Wheat plants (Triticum aestivum var. INTA x2018;Cinco Cerros’) were grown in pots with fine sand under a rain-out shelter to assess their response to a water shortage spanning most of the growth cycle. Three watering treatments, based on different thresholds of plant-available water, were started 8 weeks after sowing and maintained for 10 weeks. After allowing recovery from any short-term embolism, stem-segment and root-system hydraulic conductances were then measured by standard low-pressure methods. Stress treatments reduced, as compared to controls, tiller number (by 31% and 41% for moderate and intense drought, respectively), total plant biomass (by 21% and 52%) and total plant leaf area (43% and 68%). The capacity of stems to transport water was reduced only by the most intense treatment (and then by no more than 50%), but root-system hydraulic conductance (kR) was strongly reduced by both treatments (37% and 80%, respectively). The transport capacity of belowground structures decreased not only on an absolute basis (kR), but also per unit root mass (KRS: 51% and 83%) and per unit of leaf area (KRL: 23% and 73%). Simulation of maximum transpiration under different soil and plant water conditions indicate that these changes in plant hydraulics had a significant impact on either transpiration at the leaf level or leaf water status for a given transpiration rate.

Keywords

hydraulic conductanceTriticum aestivumwater stresswhole-plant response

Abbreviations

C

control

ID

intense-drought treatment

MD

moderate-drought treatment

KHact.

actual stem hydraulic conductivity

KHpotl.

potential stem hydraulic conductivity

KHS

stem specific conductivity (cross-section area basis)

KHL

stem leaf-specific conductivity

kR

root-system hydraulic conductance

KRS

root-system specific conductivity (root biomass basis)

KRL

root-system leaf-specific conductivity

PAW

plant available water

ψW

water potential

Copyright information

© Springer 2005

Authors and Affiliations

  1. 1.IFEVA, CONICET/Facultad de AgronomíaUniversidad de Buenos AiresBuenos AiresArgentina