Measurement of Malic Acid Diel Fluctuation of Leaves in Three Dendrobia

Employing high performance liquid chromatography(HPLC),the diel fluctuation of malic acid content of mesophyll cells in three dendrobia named as below was explored,while Kalanchoe blossfeldiana and K.daigremontiana were selected as control material in the research.The results demonstrated that Dendrobium primulinum exhibited obviously the typical characteristics of crassulacean acid metabolism plants,which mean that the diel rhythm of malate content changed regularly according to crassulacean acid metabolism stages.As to D.nobile,the malic acid content fluctuated rhythmly to some certain extent,but there was a significant difference in terms of quantity of malic acid and regularity of fluctuation compared to Kalanchoe daigremontiana known as obligate crassulacean acid metabolism plants.However,the malic acid content of mesophyll cells in D.chrysotoxum was extremly low,and this species did not indicated traits of crassulacean acid metabolism plants.