A Study to Detect CAM Plants in Mongolia

In order to discover CAM plants from the Mongolian flora, four species, Orostachys spinosa (L.) C.A. Mey., O. malacophylla (Pall.) Fisch., O. thyrsiflora Fisch. and Sedum aizoon L. of Crassulaceae D.C.family were examined in terms of their leaf anatomy, photosynthesis and transpiration intensity for a 24-hour cycle. Photosynthesis by these plants has been studied using isotope-discriminate analysis (δ13C)and a special method for CAM. Transpiration was measured by the weight-method and leaf anatomy andstomatal movement by microscopy. 13C/12C value of Orostachys spinosa, O. thyrsiflora C4-like (-13.44%ο,-18.10%ο), O. malacophylla, Sedum aizoon C3-like (-25.03%ο,-26.32%ο). CAM plant characters areclearly discovered in two species Orostachys spinosa and O. malacophylla. Although differences in theacidity value cycle of Sedum aizoon in terms of a 24-hour cycle was similar to the previous two plants,stomatal movement was commonly closed during night and day showing that we need to conduct morefuture studies for this species. Orostachys thyrsiflora does not have CAM photosynthetic response.