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Journal of Botany
Volume 2015 (2015), Article ID 120868, 9 pages
Research Article

Impact of Drought, Heat, and Their Combination on Chlorophyll Fluorescence and Yield of Wild Barley (Hordeum spontaneum)

1Department of Ecology, Evolution and Diversity, University of Frankfurt, Max von Laue Strasse 13, 60438 Frankfurt, Germany
2Agricultural Genetic Engineering Research Institute (AGERI), ARC, Giza 12619, Egypt
3Biodiversity and Climate Research Center, Senckenberganlage 25, 60325 Frankfurt, Germany

Received 14 July 2015; Revised 15 October 2015; Accepted 18 October 2015

Academic Editor: Zed Rengel

Copyright © 2015 Christoph Jedmowski et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The impact of (long-term) drought acclimation and (short-term) heat stress and their combination on fast chlorophyll fluorescence induction curves (OJIP) and grain yield was tested using pot-grown plants of wild barley (Hordeum spontaneum) originating from Northern Egypt. Concerning agronomic traits, the main effect of drought was decreased biomass accumulation and grain yield, while heat specifically affected floral development. The treatments caused specific inhibitions of photosystem II (PSII) functionality. While heat stressed plants showed a reduction of maximum quantum efficiency of PSII (), an indication of effects on oxygen evolving complex (OEC) functionality, and the connectivity of PSII units, these features were entirely missing in drought acclimated plants. Drought caused a reduction of the Performance Index () and of the relative amplitude of the IP-phase of the OJIP induction curve (). Individuals suffering from a combination of drought and heat showed a better ability to recover photosynthetic electron transport after the relief of stress in comparison to heat stressed plants. However, this improved capacity to recover was not accompanied by an increased grain yield. Thus, we conclude that chlorophyll fluorescence measurements provide valuable physiological data; however, their use in agronomic studies for the prediction of agronomic traits should be done with some precaution.