Costs of furanocoumarin defense

Costs of defense come in several flavors.  Costs associated with furanocoumarin production in wild parsnips are of three types, genetic correlations, phenotypic correlations, and physiological correlations.  Significant negative genetic correlations were found between levels of furanocoumarins in seeds and numbers of flowers produced.  In other words, genotypes that invest heavily in seed furanocoumarins also tend to produce fewer flowers.
seedcost.JPG (42298 bytes)
Phenotypic correlation

Plants that endow their seeds with larger quantities of furanocoumarins produce less total seed biomass.




costdam.JPG (53605 bytes) Cost of induction

Plants that were induced to produce furanocoumarins by inflicting minimal damage (~2% of the leaf area was damaged, see furano- coumarin induction) accumulated on average 8% less biomass compared to plants that were left intact.

respir.JPG (67672 bytes) Physiological Cost Damage-induced furanocoumarin production was associated with significant increases in dark respiration.  The resulting increase in furanocoumarin concentration was positively correlated with the increase in respiration. Moreover, all of the increase in respiration can be accounted for by the increase in furanocoumarins (based on theoretical costs of de novo synthesis of   furanocoumarins).

last updated 1/11/2000