New Directions in Ecophysiology

Plant ecophysiology has several new and potentially important contributions to make to biology. The rapidly growing human population requires increasing supplies of food, fiber, and energy, at a time when the best agricultural land is already in production or being lost to urban development and land degradation. It is thus increasingly critical that we identify traits or suites of traits that maximize sustainable food and fiber production on both highly productive and less productive sites. The development of varieties that grow effectively with inadequate supplies of water and nutrients is particularly important in less developed countries that often lack the economic and transportation resources to support high-intensity agriculture. Molecular biology and traditional breeding programs provide the tools to develop new combinations of traits in plants, including GMOs (genetically modified organisms). Ecophysiology is perhaps the field that is best suited to determine the costs, benefits, and consequences of changes in these traits, as whole plants, including GMOs, interact with complex environments.

Past ecophysiological studies have described important physiological differences among plant species and have demonstrated many of the mechanisms by which plants can live where they occur. These same physiological processes, however, have important effects on the environment, shading the soil, removing nutrients that might otherwise be available to other plants or soil microorganisms, transporting water from the soil to the atmosphere, thus both drying the soil and increasing atmospheric moisture. These plant effects can be large and provide a mechanistic basis for understanding processes at larger scales, such as community, ecosystem, and climatic processes (Chapin 2003). For example, forests that differ only in species composition can differ substantially in productivity and rates of nutrient cycling. Simulation models suggest that species differences in stomatal conductance and rooting depth could significantly affect climate at regional and continental scales (Foley et al. 2003, Field et al. 2007). As human activities increasingly alter the species composition of large portions of the globe, it is critical that we understand the ecophysiological basis of community, ecosystem, and global processes.

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