Partitioning hydraulic resistance in Sorghum bicolor leaves reveals unique correlations with stomatal conductance during drought

Ocheltree, T.W. and Nippert, J.B. and Kirkham, M.B. and Prasad, P.V.V. (2013) Partitioning hydraulic resistance in Sorghum bicolor leaves reveals unique correlations with stomatal conductance during drought. Functional Plant Biology. pp. 1-12.

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Abstract

The hydraulic architecture of leaves represents the final path along which liquid water travels through the plant and comprises a significant resistance for water movement, especially for grasses. We partitioned leaf hydraulic resistance of six genotypes of Sorghum bicolor L. (Moench) into leaf specific hydraulic resistance within the large longitudinal veins (r* LV) and outside the large veins (r* OLV), and correlated these resistances with the response of stomatal conductance (gs) and photosynthesis (A) to drought. Under well-watered conditions, gs was tightly correlated with r* OLV (r2 = 0.95), but as soil moisture decreased, gs was more closely correlated with r* LV (r2 = 0.97). These results suggest that r* OLV limits maximum rates of gas exchange, but the ability to efficiently move water long distances (low r* LV) becomes more important for the maintenance of cell turgor and gas exchange as soil moisture declines. Hydraulic resistance through the leaf was negatively correlated with evapotranspiration (P < 0.001) resulting in more conservative water use in genotypes with large leaf resistance. These results illustrate the functional significance of leaf resistance partitioning to declining soil moisture in a broadly-adapted cereal species.

Item Type: Article
Additional Information: Financial support was provided, in part, by the Kansas Technology Enterprise Corporation, The Konza Prairie LTER (DEB-0823341), and the K-State Center for Sorghum Improvement, and the Kansas Agriculture Experiment Station, contribution number 13–156-J.
Uncontrolled Keywords: drought tolerance, leaf hydraulic conductance, stomatal conductance, plant anatomy.
Author Affiliation: ADepartment of Forest Resources, University of Minnesota, 1530 Cleveland Avenue N., St. Paul,MN55108, USA.
Subjects: Crop Improvement
Divisions: Sorghum
Depositing User: Mr Siva Shankar
Date Deposited: 30 Oct 2013 09:58
Last Modified: 30 Oct 2013 09:58
Official URL: http://dx.doi.org/10.1071/FP12316
URI: http://eprints.icrisat.ac.in/id/eprint/12058

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