Measuring Gas Exchange in Arid Environments
Arid environments cover 33% of the Earth's terrestrial surface area and the environmental parameters of these biomes has caused the plants that inhabit them to have unique mechanisms and lifecycle patterns. The most obvious of these adaptations for temperate arid lands is CAM photosynthesis, a biochemical adaptation to high heat, high quantum flux, and low water availability. CAM is an extension of C3 photosynthesis that temporally fixes CO2 allowing the plant's stomatal cycles to be reversed. Stomates open during the night to allow CO2 fixation without excessive H2O loss, storing the CO2 as crassulacean acid until light is available. During the day, the acid is converted back to CO2 and combined with the energetic matabolites from the light reactions to complete the photosynthetic carbon reaction chain.
Another consideration is the lifestyle adaptation of these plants. They tend to grow either very slowly or very quickly, which must be considered when choosing a photosynthesis measurement regime or field campaign. Plant phenology must also be considered, as arid environment plants tend to have adaptations to conserve what little water they can acquire including small leaves or waxy cuticles.
LI-COR Photosynthesis Systems:
The LI-6400XT and LI-6800 Portable Photosynthesis Systems are compact, rugged, field portable instruments able to provide researchers with detailed information on plant responses such as CO2 assimilation rates, stomatal conductance, intercellular CO2 concentrations, carboxylation and light use efficiencies, and CO2 and light compensation points. The LI-6800 is our newest system, featuring a touch-screen interface and improvements in gas analyzer precision, better control over chamber conditions, and more.
LI-COR Instruments for Arid Photosynthesis
Designed for use with thick, fleshy or cylindrical leaves, or leaves with thick vasculature.