Species-specific response of glucosinolate content to elevated atmospheric CO2

Journal Article (Journal Article)

The carbon/nutrient balance hypothesis has recently been interpreted to predict that plants grown under elevated CO2 environments will allocate excess carbon to defense, resulting in an increase in carbon-based secondary compounds. A related prediction is that, because plant growth will be increasingly nitrogen-limited under elevated CO2 environments, plants will allocate less nitrogen to defense, resulting in decreased levels of nitrogen-containing secondary compounds. We present the first evidence of decreased investment in nitrogen-containing secondary compounds for a plant grown under elevated CO2. We also present evidence that plant response is species-specific and is not correlated with changes in leaf nitrogen content or leaf carbon-nitrogen ratio. When three crucifers were grown at 724 ± 8 ppm CO2, total foliar glucosinolate content decreased significantly for mustard, but not for radish or turnip. Glucosinolate content of the second and fourth youngest mustard leaves decreased by 45% and 31%, respectively. In contrast, no significant change in total glucosinolate content was observed in turnip or radish leaves, despite significant decreases in leaf nitrogen content. Total glucosinolate content differed significantly among leaves of different age; however, the trend differed among species. For both mustard and turnip, glucosinolate content was significantly higher in older leaves, while the opposite was true for radish. No significant CO2 x leaf age interaction was observed, suggesting that intraplant patterns of allocation to defense will not change for these species. Changes in nitrogen allocation strategy are likely to be species-specific as plants experience increasing atmospheric CO2 levels. The ecological consequences of CO2-induced changes in plant defensive investment remain to be investigated.

Full Text

Duke Authors

Cited Authors

  • Karowe, DN; Seimens, DH; Mitchell-Olds, T

Published Date

  • January 1, 1997

Published In

Volume / Issue

  • 23 / 11

Start / End Page

  • 2569 - 2582

International Standard Serial Number (ISSN)

  • 0098-0331

Digital Object Identifier (DOI)

  • 10.1023/B:JOEC.0000006667.81616.18

Citation Source

  • Scopus