Comparisons of genetic diversity in the endangered Adenophora lobophylla and its widespread congener, A-potaninii

Starch-gel electrophoresis was used to examine The levels and distribution of genetic diversity in two Adenophora species: the narrow endangered Adeno phora lobophylla and its widespread congener, A. pot aninii Based on allozy me variation at 18 putative loci, we measured high levels of genetic variab ility both in the endangered and the widespread species, with 83.3% of the loci being polymorphic. The mean expected her erozygosity within population s (H-ep) and within species (H-es) were 0.234 and 0.244 for A. potaninii an d were ns high as 0.210 and 0.211 for A. lobophylla There teas higher diffe rentiation among populations in A. potaninii (F-ST = 0.155) than in A. lobo phylla (F-ST = 0.071). The high levels of genetic diversity in the present allozyme survey are consistent with the morphological variation observed in these species and may be attributed to high outcrossing rates in the Adeno phora species. In addition, A. lobophylla was identified as a distinct spec ies on The basis of Nei's genetic distances and thus should De given a high priority for protection. It is noteworthy that the endangered A. lobophyll a maintains much higher genetic diversity than most endemic or narrowly dis tributed plant species in spice of its restricted distribution. We hypothes ize that A. lobophylla has become endangered for ecological and stochastic reasons, including habitat destruction or environmental changes mud slides, and human disturbance such as grazing and mowing. Consequently, habitat pr otection is of particular importance for conserving this endangered species .