Symbioses: Plant, Animal, and Microbe Interactions
Cameron, Duncan D , Těšitel, Jakub .
How parasitic are hemiparasitic plants? Estimating heterotrophic carbon gain by Rhinanthus minor and Euphrasia rostkoviana (Orobanchaceae).
Hemiparasitic plants gain virtually all mineral nutrients and water from their host plant while organic carbon is provided, at least in part, by their own photosynthetic activity although their rates of assimilation are substantially lower than that found in non-parasitic plants. Hence, hemiparasites must gain at least some of their organic carbon heterotrophically from the host plant. Despite this, heterotrophic carbon gain by root hemiparasites has been investigated only for a few genera. We investigated heterotrophic carbon gain by two root hemiparasites Rhinanthus minor L. and Euphrasia rostkoviana Hayne (Orobanchaceae) using natural abundance stable isotope (Î´13C) profiles of both parasites attached to C3 (wheat) and C4 (maize) hosts coupled to a linear two-source isotope mixing model to estimate the percentage of carbon in the parasite that was derived from the host. Both R. minor and E. rostkoviana attached to maize hosts were significantly more enriched in 13C than those attached to wheat hosts with R. minor becoming more enriched in 13C than E. rostkoviana. The natural abundance 13C profiles of both parasites were not significantly different from their wheat hosts but were less enriched in 13C than maize hosts. Using a linear two-source isotope mixing model we estimated that R. minor and E. rostkoviana adult plants derive c. 50 and 25% of their carbon from their hosts respectively. In light of these results, we hypothesize that repeatedly observed negative effect of competition for light on hemiparasites acts predominantly in early ontogenetic stages when parasites grow unattached or the abstraction of host nutrients in less effective.
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1 - University of Sheffield, Department of Animal and Plant Sciences, Alfred Denny Building, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK
2 - University of South Bohemia, Department of Botany, Ceske Budejovice, Czech Republic
Presentation Type: Oral Paper:Papers for Topics
Location: 553B/Convention Center
Date: Monday, August 2nd, 2010
Time: 2:15 PM