PARENT SESSION
Poster Session #36: Seed Production, Recruitment, and Pollination.
Wednesday, August 7. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

A new technique to determine seedling parenthood using a stable isotope marker.

Carlo, Tomas^*,1, Martinez del Rio, Carlos², ¹ University of Colorado, Boulder, CO² University of Wyoming, Laramie, WY

ABSTRACT- Many fundamental questions in plant ecology require the measurement of seed-dispersal parameters that rely on the unambiguous identification of a seed or seedling from its source (mother plant). A multitude of techniques have been employed for that purpose, mostly resulting in either effective but expensive and time-consuming techniques (e.g., genetic markers), or in cheap and unreliable ones (e.g., painting seeds, following animal dispersers). We sprayed solutions of N¹⁵ - labeled urea (99% atom) of different concentrations, on adult plants of Solanum americanum and Cestrum diurnum bearing flower buds at 3 and 6-day intervals in a greenhouse. After mass-spectrometry, we found that plants from both treatments incorporated the nitrogen into their vegetative parts, particularly the developing seeds. More significant was that after collecting and planting seeds from labeled parent plants, the N¹⁵ signal was still present well above background level in seedlings of up to 70 mg (newly germinated seedlings weight around 0.35 mg). Transmitted N¹⁵ signals in the F-1 of labeled plants reached levels of up to 8,000 times that of the background level (control). These findings open a new suite of possibilities for the study of seed-dispersal as some adult plants could be labeled in field conditions and their propagules traced with high accuracy and relatively low effort and cost.

KEY WORDS: seed-dispersal, N-15 stable isotope markers