The effect of photosynthetic parameters on species acclimation in an arid mountainous region of China

Abstract

Understanding the mechanisms of how environmental factors limit species distribution along environmental gradients isa central question in ecology. This study aimed to understand species acclimation in view of photosynthetic parameters in an aridmountainous region. We measured some photosynthetic parameters and light and CO2 photosynthesis response curves for all plantcommunities with seven dominant species in 13 sites along an elevation gradient in the Qilian Mountains in arid northwestern China.The results showed that species in xerothermic environments had low maximum rate of carboxylation (Vcmax) (14.5 μmol m–2 s–1) andmaximum rate of electron transport (Jmax) (22.7 μmol m–2 s–1), high light compensation points (60.0 μmol m–2 s–1) and light saturationpoints (1150.7 μmol m–2 s–1), high dark respiration rates (5.3 μmol m–2 s–1), and high maximum photosynthetic rates (Amax) (18.1 μmolm–2 s–1) compared with species in mesic environments. Photosynthesis parameters did not vary with temperature, precipitation, andaltitude in different communities dominated by the same species, Picea crassifolia. However, some photosynthesis parameters variedwith temperature, precipitation, and altitude in communities dominated by species other than spruce at different elevations. Selectedphotosynthesis parameters could be used to measure species adaptation to environmental gradients in arid mountain regions.