Distribution of P^(32) in Ambrosia Artemisiifolia; Its Implication for Trophic Transfer Studies
1969
Shure, Donald J. | Pearson, Paul G.
Tracer studies on temporal changes in P³ ² distribution in ragweed. (Ambrosia artemisiifolia) indicated significant differences in P³ ² activity in different organs. Activity density of flower tissue was significantly greater than of other organs throughout the study. Differences between root, stem and leaf activities were only present early in the experiment when activity densities of all organs were at their highest. The total isotope pool was originally greatest in leaf tissue, being surpassed by flower tissue during the latter part of the experiment. The differences in activity density levels indicate variable amounts of P³ ² available to consumers which feed at different sites on ragweed. Leaf, flower, or whole plant activity density give quite different results in estimates of trophic transfer indices for two consumer species. Use of activity density measures from the actual site at which a consumer feeds is recommended for a more accurate estimation of trophic transfer.
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