Chen, Yigen and Schmelz, Eric A. and Wäckers, Felix L. and Ruberson, John R. (2008) Cotton Gossypium hirsutum L., defense in response to nitrogen fertilization and beet armyworm density. Journal of Chemical Ecology, 34 (12). pp. 1553-1564. ISSN 0098-0331Full text not available from this repository.
Plants respond to insect herbivory by producing dynamic changes in an array of defense-related volatile and nonvolatile secondary metabolites. A scaled response relative to herbivory levels and nutrient availability would be adaptive, particularly under nutrient-limited conditions, in minimizing the costs of expressed defensive pathways and synthesis. In this study, we investigated effects of varying nitrogen (N) fertilization (42, 112, 196, and 280 ppm N) on levels of cotton plant (Gossypium hirsutum) phytohormones [jasmonic acid (JA) and salicylic acid (SA)], terpenoid aldehydes (hemigossypolone, heliocides H1, H2, H3, and H4), and volatile production in response to beet armyworm (Spodoptera exigua) herbivory. Additional bioassays assessed parasitoid (Cotesia marginiventris) host-searching success in response to cotton plants grown under various N fertilizer regimes. At low N input (42 ppm N), herbivore damage resulted in significant increases in local leaf tissue concentrations of JA and volatiles and in systemic accumulation of terpenoid aldehydes. However, increased N fertilization of cotton plants suppressed S. exigua-induced plant hormones and led to reduced production of various terpenoid aldehydes in damaged mature leaves and undamaged young leaves. While increased N fertilization significantly diminished herbivore-induced leaf volatile concentrations, the parasitism of S. exigua larvae by the parasitoid C. marginiventris in field cages did not differ among N treatments. This suggests that, despite significant N fertilization effects on herbivore-induced plant defenses, at short range, the parasitoids were unable to differentiate between S. exigua larvae feeding on physiologically different cotton plants that share large constitutive volatile pools releasable when damaged by herbivores.
|Journal or Publication Title:||Journal of Chemical Ecology|
|Uncontrolled Keywords:||Plant–herbivore interactions - Tritrophic interactions - Plant resistance - Direct defense - Indirect defense - Spodoptera exigua - Malvaceae - Hymenoptera - Lepidoptera - Noctuidae - Braconidae - Cotesia marginiventris - Optimal defense (OD) theory|
|Subjects:||G Geography. Anthropology. Recreation > GE Environmental Sciences|
|Departments:||Faculty of Science and Technology > Lancaster Environment Centre|
|Deposited By:||Mr Richard Ingham|
|Deposited On:||16 Nov 2009 15:07|
|Last Modified:||26 Jul 2012 16:45|
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