Do differences in plasticity during early growth lead to differing success in competition? A test using four co-occurring annual Papaver

31 Plant species differ in their ability to transform available recourses to biomass and to respond 32 in a plastic way to environmental circumstances; we hypothesized that such differences 33 among four weed taxa of Papaver would explain differences in their competitive response. 34 We first compared two populations each of Papaver rhoeas L., P. dubium L. ssp. dubium, P. 35 dubium L. ssp. lecoqii (Lamotte) Syme and P. argemone L., grown in greenhouse for six 36 weeks in a nutrient gradient combined with two light treatments to elucidate possible 37 differences in responses. As there were clear differences, a second experiment evaluated 38 whether these differences also meant differences in competitive response, during early 39 growth, when tested against two crops (wheat, rape). The assumption that competitive 40 response was linked to the ability to transform nutrient and light to biomass was not 41 supported: even though differences in extent of plasticity existed, the effect of competition 42 was similar for the taxa. Thus, higher plasticity and ability to transform available recourses to 43 biomass did not lead to stronger competitiveness for Papaver during early growth. 44