TY - JOUR T1 - Photosynthetic Response of Yellow-Poplar Seedlings to the Antioxidant Chemical Ethylenediurea JF - Arboriculture & Urban Forestry (AUF) JO - JOA SP - 154 LP - 158 DO - 10.48044/jauf.1987.033 VL - 13 IS - 6 AU - Bruce R. Roberts Y1 - 1987/06/01 UR - http://auf.isa-arbor.com/content/13/6/154.abstract N2 - An antioxidant chemical, ethylenediurea (EDU), was applied by soil drench or by stem injection to 2-yr-old containerized seedlings of yellow-poplar (Liriodendron tulipifera) growing in the greenhouse. Net photosynthesis (Pn) was measured before EDU treatment and again 2, 4, and 7 days after treatment. The same seedlings were then fumigated with 0, 0.35 or 0.95 ppm ozone (O3) for 3 hr and Pn remeasured after 2 days. No significant change in Pn was observed for those seedlings treated with EDU (either soil drench or stem injection) when compared to the controls. Following O3 fumigation, the decline in Pn for EDU-treated seedlings was appreciably less than that for seedlings without EDU. Stomatal conductance measurements taken on foliage from EDU-treated and untreated plants, both before and after O3 fumigation, suggest that EDU may affect Pn indirectly through its influence on stomatal opening. ER -