Germination of CO2-enriched Pinus taeda L. seeds and subsequent seedling growth responses to CO2 enrichment
Abstract
1. Pinus tuedli seeds, developed under ambient or elevated (ambient + 200 Ч1-1) [CO2], were collected from Duke Forest, North Carolina, USA in October 1998. Seeds were germinated in nutrient-deficient soil in either ambient or elevated [COJ (ambient + 200 Ч1-1) greenhouse chambers and allowed to grow for 120 days. 2. Seeds that developed in elevated [CO2 had 91 and 265% greater weight and lipid content, respectively, and three times the germination success, compared to those developed in current ambient [CO2]. 3. Seedlings from the elevated [CO2] seed source had significantly greater root length and more needles regardless of greenhouse chamber, but there were no treatment effects on tissue or total biomass. 4. Severely limiting nutrient conditions resulted in significant photosynthetic downregulation by seedlings grown in greenhouse chambers with elevated [CO2], regardless of seed source. 5. Our hypothesis that greater seed reserves from CO2 enrichment would synergistically affect seedling growth responses to elevated [CO2] was not strongly supported. Nonetheless, seeds produced in a C02-enriched environment may have fundamental changes in their viability, chemistry and germination that may affect reproduction.