Ecophysiological responses of desert plants to elevated CO2 : environmental determinants and case studies

Some of the early work on the responses of desert plants to elevated CO2 was conducted by Park Nobel and his students and post-docs (e.g., Nobel and Hartstock 1986). Clearly, Park saw that this was an important topic before elevated CO2 research was "in vogue". It is therefore appropriate, as a chapter in this Festschrift, that we summarize advances that have been made in elevated CO2 research over the past several decades. Although none of the authors in this chapter conducted elevated CO2 research while in Park's lab, we subsequently conducted a significant amount of elevated CO2 research in our respective careers, often forming collaborations that we developed in Park's lab. In each of our careers, and in our specific approaches to elevated CO2 research, we applied unique skills that we developed in his lab to the experimental problem at hand. As a result of this "bias", we will concentrate this review on plants from resource-limited environments, particularly deserts, and we will also explicitly address the interactions between elevated CO2 and environmental stress, a relatively neglected area of elevated CO2 research. In the first part, we will concentrate on key process studies with respect to various environmental stresses, and then in the second part we will address some Case Studies in which Park Nobel and his former students and post-docs have made important contributions to our understanding of how elevated CO2 may impact plant performance in resource-limited environments.