EFFECTS OF ENVIRONMENTAL FACTORS ON THE POPULATION GENETIC DIVERSITY IN THE CHINESE ENDANGERED AND ENDEMIC MEDICINAL PLANT NOTOPTERYGIUM INCISUM

Correlation between environmental factors and genetic diversity of 23 populations throughout the distribution range of Notopterygium incisum was examined using nuclear internal transcribed spacer gene fragment (ITS) and chloroplast DNA (cpDNA) rpl20-rps12 intergenic spacer. A total of 635 nucleotides of ITS were sequenced from 343 individuals. 26 haplotypes were defined by 26 variable sites. A total of 772 nucleotides of rpl20-rps12were sequenced from 253 individuals. 30 haplotypes were defined by 26 variable sites. Based on cpDNA rpl20-rps12 region, the correlations between the haplotype diversity, nucleotide diversity and environmental factors were all non-significant. However, based on ITS sequences, a significant positive relationship was observed between haplotype diversity and ammonium nitrogen, annual average rainfall and elevation, as well as between nucleotide diversity and ammonium nitrogen and annual average rainfall. Synchronously, significant negative relationships were observed between haplotype diversity and latitude and variation coefficient of rainfall, as well as between nucleotide diversity and latitude. Latitude, elevation, annual average rainfall, variation coefficient of rainfall and ammonium nitrogen were the dominant factors that influenced the genetic diversity of N. incisum. The genetic diversity of N. incisum tended to increase in the environment with lower latitude, more rainfall, more ammonium nitrogen, higher elevation and a more stable climate.