Plant gas exchange and water status in urban desert landscapes

Gas exchange and water status were evaluated for plants at irrigated residential and unirrigated remnant Sonoran Desert sites in the greater Phoenix area, Arizona, U.S.A. Gas exchanges fluxes were higher for plants at the residential sites than for those at the desert sites. Plant water status was more favorable at residential sites for every season except the late summer monsoon, and time of day for maximum photosynthesis was later for residential plants during summer and winter months. These data suggest that yearly CO2 uptake was a function of plant water status and summer heat stress, and land use in these urban desert landscapes.