Changes in the stress tolerance of two Mojave Desert perennial shrubs after eight years of growth in elevated carbon dioxide.

摘要

Global climate change is a significant issue facing modern society. Potential changes include increased atmospheric CO2 concentrations, increased temperature, altered precipitation patterns, and increased nitrogen deposition. The Nevada Desert FACE (Free Air Carbon dioxide Enrichment) Facility (NDFF) examines the effects of increased atmospheric CO2 concentration in an arid ecosystem. The effects of elevated CO2 on plants include increased growth rates and stress tolerance. This study examined the mechanistic changes in drought tolerance of two dominant Mojave Desert shrubs ( Larrea tridentata and Ambrosia dumosa) grown in elevated (550 mumol mol-1) or ambient (380 mumol mol -1) CO2 concentrations. Previous studies at this site included photosynthetic, water potential, and fluorescence investigations. This study added a mechanistic approach, investigating the possible photosynthetic down-regulation and increased drought-tolerance after growth in elevated CO2, including pigment, sugar, and protein analyses. In contrast to past studies, Larrea tridentata plants growing in elevated CO2 exhibited photosynthetic upregulation, but as expected, both species exhibited increased drought tolerance through reduced stomatal conductance, as elevated CO 2 had few effects on sugars, proteins, or protective pigments.