Like herbivores,parasitic plants are limited by host nitrogen content |
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Authors: | Steven C Pennings Juliet C Simpson |
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Institution: | (1) Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA;(2) Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA |
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Abstract: | Herbivores generally benefit from increased plant nitrogen content, because the nitrogen content of animals is much higher
than that of plants. Consequently, high plant nitrogen alleviates the profound stoichiometric imbalance that herbivores face
in their diets. Parasitic plants provide the opportunity to test this generalization for consumers across kingdoms. We fertilized
two microhabitats in a California salt marsh that were dominated by Salicornia virginica or a mixture of S. virginica and Jaumea carnosa. The nitrogen content of both host plants and of the holoparasite Cuscuta salina (dodder) increased in fertilized plots in both microhabitats. Cuscuta preferred to attack Jaumea, although Jaumea had lower nitrogen content than Salicornia. When host nitrogen content was altered by fertilizing plots, however, the percent cover of the parasite doubled. Although
parasitic plants and their hosts have similar tissue nitrogen contents, suggesting no stoichiometric imbalance between host
and consumer, parasitic plants do not feed on host tissue, but on host xylem and phloem, which are very low in nitrogen. Consequently,
parasitic plants face the same dietary stoichiometric constraints as do herbivores, and both herbivores and holoparasitic
plants may respond positively to increases in host nitrogen status. |
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Keywords: | Cuscuta Fertilization experiment Nitrogen Parasitic plant |
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