The role of low-level ozone exposure and mycorrhizas in chemical quality and insect herbivore performance on Scots pine seedlings

Research output: Contribution to journalArticle

Abstract

The effects of low-level ozone exposure and suppression of natural mycorrhizas on the above-ground chemical quality of Scots pine (Pinus sylvestris L.) needles and insect herbivore performance were studied in a two-year field experiment. Seedlings were fumigated with the ozone doses 1.5–1.7 times the ambient, and natural mycorrhizal infection level was about 35% reduced in roots with fungicide propiconazole. On ozone-exposed seedlings the mean relative growth rate (MRGR) of Lygus rugulipennis Popp. nymphs was lower than on ambient ozone seedlings, but Gilpinia pallida Klug sawfly larvae grew better on elevated ozone seedlings than on ambient ozone seedlings. MRGR of Schizolachnus pineti Fabr. and Cinara pinea L. aphid nymphs or Neodiprion sertifer Geoffr. sawfly larvae or the oviposition of L. rugulipennis and N. sertifer were not affected by ozone exposure. Although ozone exposure did not affect total phenolics, total terpene, total or individual resin acid, total free amino acid, nutrient or sugar concentrations in needles, MRGR of L. rugulipennis positively correlated with total terpenes and MRGR of G. pallida positively with total amino acids. In addition, ozone exposure increased serine and proline concentration and marginally also starch concentration in needles. When mycorrhizas were reduced with fungicide, only MRGR of L. rugulipennis nymphs increased, but performance of other insect herbivores studied was not changed. However, number of L. rugulipennis eggs correlated positively with mycorrhizal infection level and also with total sugars. Reduction of mycorrhizas did not strongly affect the concentrations of analysed compounds in needles, because only phosphorus and potassium and some individual resin acids were reduced by fungicide treatment. These results suggest that low-level ozone exposure and moderately declined mycorrhizal infection do not drastically affect either the above-ground chemical quality of Scots pine seedlings or performance of studied insect herbivores.

Details

Authors
  • AM Manninen
  • T Holopainen
  • Päivi Lyytikäinen-Saarenmaa
  • JK Holopainen
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Ecology
Original languageEnglish
Pages (from-to)111-121
JournalGlobal Change Biology
Volume6
Issue number1
Publication statusPublished - 2001
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Ecology/Ecotoxicology (Closed 2011) (011006020), Department of Ecology (Closed 2011) (011006010)