Journal of Chemical Ecology

, Volume 34, Issue 12, pp 1553–1564

Cotton Plant, Gossypium hirsutum L., Defense in Response to Nitrogen Fertilization

  • Yigen Chen
  • Eric A. Schmelz
  • Felix Wäckers
  • John R. Ruberson
Article

Abstract

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.

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 

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Yigen Chen
    • 1
  • Eric A. Schmelz
    • 2
  • Felix Wäckers
    • 3
  • John R. Ruberson
    • 4
  1. 1.Department of EntomologyMichigan State UniversityEast LansingUSA
  2. 2.Center of Medical, Agricultural, and Veterinary EntomologyUSDA Agricultural Research ServiceGainesvilleUSA
  3. 3.Centre for Sustainable Agriculture, Lancaster Environment CentreLancaster UniversityLancasterUK
  4. 4.Department of EntomologyUniversity of GeorgiaTiftonUSA

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