Journal Article

PreJuSER-9027

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Herbivory of wild Manduca sexta causes fast down-regulation of photosynthetic efficiency in Datura wrightii: an early signaling cascade visualized by chlorophyll fluorescence

Barron-Gafford, G. A. ; Rascher, U.FZJ* ; Bronstein, J. L.FZJ* ; Davidowitz, G. ; Chaszar, B. ; Huxman, T. E.

2012
Springer Science + Business Media B.V Dordrecht [u.a.]

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Please use a persistent id in citations: doi:10.1007/s11120-012-9741-x

Abstract: Plants experiencing herbivory suffer indirect costs beyond direct loss of leaf area, but differentially so based on the herbivore involved. We used a combination of chlorophyll fluorescence imaging and gas exchange techniques to quantify photosynthetic performance, the efficiency of photochemistry, and heat dissipation to examine immediate and longer-term physiological responses in the desert perennial Datura wrightii to herbivory by tobacco hornworm, Manduca sexta. Herbivory by colony-reared larvae yielded no significant reduction in carbon assimilation, whereas herbivory by wild larvae induced a fast and spreading down-regulation of photosynthetic efficiency, resulting in significant losses in carbon assimilation in eaten and uneaten leaves. We found both an 89 % reduction in net photosynthetic rates in herbivore-damaged leaves and a whole-plant response (79 % decrease in undamaged leaves from adjacent branches). Consequently, herbivory costs are higher than previously estimated in this well-studied plant-insect interaction. We used chlorophyll fluorescence imaging to elucidate the mechanisms of this down-regulation. Quantum yield decreased up to 70 % in a small concentric band surrounding the feeding area within minutes of the onset of herbivory. Non-photochemical energy dissipation by the plant to avoid permanent damage was elevated near the wound, and increased systematically in distant areas of the leaf away from the wound over subsequent hours. Together, the results underscore not only potential differences between colony-reared and wild-caught herbivores in experimental studies of herbivory but also the benefits of quantifying physiological responses of plants in unattacked leaves.

Keyword(s): J ; Herbivory (auto) ; Datura wrightii (auto) ; Manduca sexta (auto) ; Down regulation (auto) ; Mutualism (auto) ; Antagonism (auto)

Note: We thank Abreeza Zegeer for greenhouse assistance and Katherine Grieve Rascher, Bryan Helm, and Kristen Potter for assistance in conducting measurements or providing larvae. This study was primarily supported by the National Science Foundation grants to J.L.B., G. D. and T. E. H. (DEB 0316205 and 0522431) and to U. R. (INT-0340609). Additional support was provided by the Philecology Foundation of Fort Worth Texas and the Forschungszentrum Julich GmbH.

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Research Program(s):

1. Terrestrische Umwelt (P24)

Appears in the scientific report 2012

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Database coverage:
; BIOSIS Previews ; Current Contents - Agriculture, Biology and Environmental Sciences ; Current Contents - Life Sciences ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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