Abstract: Disanthus is an endemic and endangered genus in East Asia and distributed disjunctively in China and Japan. In this project, we conducted the phylogenetic study of 164 individual plants in 16 natural populations of Disanthus based on the 3 fragments(psbA-trnH, rps16F-R2, and psaA-ycf3)of chloroplast DNA(cpDNA). The results of the phylogenetic relationship confirmed that Disanthus gercidifolius in Japan and Disanthus cercidifolius subsp. Longipes in China were monophyletic groups, and they had no share of haploid type. Furthermore, Japanese populations could be divided into 2 geographical branches, one from the center of Honshu(population QE and CY), and the other from the southwestern Honshu(population ga, gd and JH). PERMUT analysis showed that total genetic diversity(Ht = 0.725)of Disanthus between populations was higher than the average genetic diversity(Hs = 0.148)within populations. Regarding the genetic difference between populations, Nst(0.905)was larger than Gst(0.976;P < 0.01), demonstrating that there were significantly geographical structure of pedigree. AMOVA results further revealed that genetic variation occurred mainly between populations(53.08%), while 24.11% among populations within a group and 22.80% among individuals within a population. These results indicated that the genetic differentiation within Disanthus between Chinese and Japanese subspecies were obvious.

Key words: Disanthus, endangered, phylogenetic