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Stomatal Limitation to Carbon Dioxide Assimilation in Nitrogen and Drought‐Stressed Wheat
Author(s) -
Heitholt J. J.,
Johnson R. C.,
Ferris D. M.
Publication year - 1991
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1991.0011183x003100010032x
Subject(s) - photorespiration , rubisco , stomatal conductance , carbon dioxide , water use efficiency , photosynthesis , drought stress , biology , transpiration , nitrogen , horticulture , agronomy , ecophysiology , botany , plant physiology , chemistry , ecology , organic chemistry
Both stomatal and metabolic factors have been shown to limit gas exchange rates in leaves. Two growth chamber experiments using two levels of N supply and two levels of water supply were conducted to determine the effect of N nutrition on the regulation of CO 2 as similation rate (A) and stomatal limitation to A under drough stress. Wheat ( Triticum aestivum L.) plants were soil grown under controlled conditions and subjected to no stress, N limitation, drought stress, or both N limitation and drought stress treatments when 4 wk old. After the plants were 6 wk old, A at varying CO 2 concentrations (from 0 to 550 L −1 ), A at 20 mL O 2 L ‐1 , stomatal conductance intercellular CO 2 concentration (C 1 ), leaf water potential (LWP) leaf N concentrationt, stomatal limitation to A , and ribulose bisphosphate carboxylase (rubisco) activity were determined. Drought stress reduced LWP (from‐ 0.73 to ‐1.65 MPa) and N stress reduced leaf N concentration (from > 30 to < 20g N kg ‐1 ), A , and rubisco activity. The stomatal limitation to A and water use efficiency (WUE) was lower and C 1 higher in the leaves of plants exposed to both N limitation and drought stress than those exposed to N limitation or drought stress alone or to those unstressed. High C 1 in the N ‐ limited, drought‐stressed leaves did not appear to be explained by lower rubisco activity or by photorespiration. Determining other nonstomatal factors might be necessary to explain the low WUE of N‐limited drought‐stressed leaves compared to non stressed leaves.