Year: 2007
Type: dissertation
Abstract: Plants defend themselves against feeding insects via both a constitutive; always existing \ndefense, and/or via an induced defense that is activated in response to the feeding damage. The \naim of this study was to investigate the induced defense in tomato after damage by insect larvae. \nThe hypothesis was that if larvae chose to feed on undamaged plants over damaged plants, they \nwould do so due to an induced defense in the damaged plants. Moreover, the aim was to examine \ntemporal aspects of induced defense, the difference in constitutive defense between genetically \nimproved cultivars and wild tomato plants, the possibility of interplant communication and if \ninduced defense compounds reduce the growth of larvae. \nFood preference bioassays and a larval growth experiment were made to test the \nhypotheseses. In feeding choice experiments, the larvae of the moth Spodoptera littoralis fed \nmore on leaves from undamaged plants over leaves from damaged plants, which suggest that \nthere was an induced defense in the damaged tomato plants that affected the larval behavior. The \nstrongest effect of induced defense was found two days after the initial damage, but it was present \nuntil at least eight days after the initiation of the damage. Also in wild tomato plants, the induced \ndefense was strong in recently wounded plants. There were no significant differences in \nconstitutive defense between wild tomato and genetically improved tomato cultivars. When \ninterplant communication was tested by larval feeding choice experiments, no difference was \nfound between damaged or undamaged plants neither when these had grown together nor \nseparately, which indicate that both airborne and root borne signaling can occur. Finally, when \nthe larvae were forced to feed on either damaged or undamaged plants in a larval growth \nexperiment, the larvae feeding on leaves from damaged plants showed reduced growth rate. This \nresult indicated an induced defense of the damaged plants that affected the larval physiology.
Author: Anna Eriksson
Language: English
Subfield: Insect Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W1716401290