PLANT ALLOCATION, GROWTH-RATE AND SUCCESSIONAL STATUS

1. Theory predicts a negative correlation between root (and stem) allocation and growth rate in enriched environments (RGR(max)), but evidence does not consistently support this. There is one possible supporting example from previous research in which root allocation in the field increases during old-field succession at the Cedar Creek Natural History Area, both community wide and for individual species samples, and RGR(max) declines for some important species. 2. In this study, we confirm that late successional species have lower RGR(max) for a larger sample of species (n = 28) as well as higher field root allocation. However, root allocation by seedlings does not increase for the late successional species for those same species in the greenhouse in enriched conditions; indeed it declines. 3. These results suggest that seedlings may have markedly different allocation than adults and that observed allocation patterns may be better viewed as adaptively plastic responses to resource gradients, rather than fixed species attributes that determine growth rates. Other, presumably less plastic characters (e.g. nitrogen- or water-use efficiency) may control growth rate, optimal allocation, and potentially competition and succession in this sample of plant types. 4. Leaf and stem allocation show no strong successional trend in the field or greenhouse, but do show a negative correlation with each other. Seed size is negatively correlated with growth rate, but shows no trend in relation to successional status.