Comparison of d 13 C values and gas exchange of assimilating shoots of desert plants Haloxylon ammodendron and Calligonum mongolicum with other plants

Abstract

The photosynthetic characters and water use efficiency of the desert plants Haloxylon ammodendron and Calligonum mongolicum, which grow in conditions of extreme stress, were studied. The mechanisms of their acclimation to harsh desert conditions and their potential capacity for sand stabilizing are revealed. The stable carbon isotope ratios (d 13C or 13C/12C) of leaves or assimilating shoots of desert plants growing at the southern edge of the Badain Jaran Desert were analyzed by mass spectrometry and compared. The diurnal course of net photosynthesis rate (Pn), Pn/light and Pn/CO2 curves, and water use efficiency (WUE, Pn/E) were measured by using the LI-6400 Portable Photosynthesis System. The results showed that: (1) Assimilating shoots of H. ammodendron and C. mongolicum have Kranz anatomy; (2) The d 13C values of H. ammodendron and C. mongolicum were -14.3‰ and -14.8‰, respectively, whereas the corresponding values of Caragana korshinskii, Nitraria sphaerocarpa, Hedysarum scoparium, and Reaumuria soo...