01970nas a2200229   4500008004100000245009200041210006900133300001300202490000700215520123600222653001601458653000701474653000701481653002901488653001701517653001001534653002201544100002301566700001401589700002001603856011701623       2007                        eng d00aPhotosynthetic traits in C3 and C4 grassland species in mesocosm and field environments0 aPhotosynthetic traits in C3 and C4 grassland species in mesocosm  a412 -4200 v603 aThe North American tallgrass prairie is composed of a diverse mix of C3 and C4 plant species that are subject to multiple resource limitations. C4 grasses dominate this ecosystem, purportedly due to greater photosynthetic capacity and resource-use efficiency associated with C4 photosynthesis. We tested the hypothesis that intrinsic physiological differences between C3 and C4 species are consistent with C4 grass dominance by comparing leaf gas exchange and chlorophyll fluorescence variables for seven C4 and C3 herbaceous species (legumes and non-legumes) in two different settings: experimental mesocosms and natural grassland sites. In the mesocosms, C4 grasses had higher photosynthetic rates, water potentials and water-use efficiency than the C3 species. These differences were absent in the field, where photosynthetic rates declined similarly among non-leguminous species. Thus, intrinsic photosynthetic advantages for C4 species measured in resource-rich mesocosms could not explain the dominance of C4 species in the field. Instead, C4 dominance in this ecosystem may depend more on the ability of the grasses to grow rapidly when resources are plentiful and to tolerate multiple limitations when resources are scarce.10aA:Ci curves10aC310aC410aChlorophyll fluorescence10agas exchange10aKonza10atallgrass prairie1 aNippert, Jesse, B.1 aFay, P.A.1 aKnapp, Alan, K.  uhttp://knz.lternet.edu/content/photosynthetic-traits-c3-and-c4-grassland-species-mesocosm-and-field-environments