Flowering time and elevated atmospheric CO2

Flowering is a critical milestone in the life cycle of plants, and changes in the timing of flowering may alter processes at the species, community and ecosystem levels. Therefore understanding flowering-time responses to global change drivers, such as elevated atmospheric carbon dioxide concentrations, [CO2], is necessary to predict the impacts of global change on natural and agricultural ecosystems. Here we summarize the results of 60 studies reporting flowering-time responses (defined as the time to first visible flower) of both crop and wild species at elevated [CO2]. These studies suggest that elevated [CO2] will influence flowering time in the future. In addition, interactions between elevated [CO2] and other global change factors may further complicate our ability to predict changes in flowering time. One approach to overcoming this problem is to elucidate the primary mechanisms that control flowering-time responses to elevated [CO2]. Unfortunately, the mechanisms controlling these responses are not known. However, past work has indicated that carbon metabolism exerts partial control on flowering time, and therefore may be involved in elevated [CO2]-induced changes in flowering time. This review also indicates the need for more studies addressing the effects of global change drivers on developmental processes in plants.