Abstract: Acer truncatum is an endangered plant endemic to China. Our objectives were to determine the variations in phenotypic traits of A. truncatum populations and their spatial patterns. We used nested variation, coefficient of variation, multicomparison, correlation analysis and UPGMA cluster analysis to analyze 13 phenotypic traits of fruits and seeds for 150 individuals in 15 populations of A. truncatum. The results showed that there were extremely significant differences among and within populations. The mean coefficient of phenotypic differentiation between populations was 19.87%, which was lower than that within populations (80.13%), indicating that the variance within population was the main source of the phenotypic variation of the species. The coefficient of variance (CV) of the 13 traits was 8.98%-21.45%, with an average of 13.34%. The CV of seeds among populations (11.46%) was lower than that of wing fruits (14.52%), which means that the seeds have higher stability than the fruits. Principal component analysis (PCA) showed that the main variation source of A. truncatum came from the fruits. Correlation among traits showed that the larger the fruits, the larger the seeds. The angle of the fruits was independent of the fruits and seed sizes. The fruit morphology mainly presented longitudinal variations, while the seeds had no significant variation patterns. The 15 populations of A. truncatum could be clustered into three groups according to the UPGMA cluster analysis. The multiple variations among and within populations provided insights and guidelines for genetic conservation and utilization of A. truncatum germplasm resources.

Key words: rhizosphere, rice, non-rhizosphere, selenium, availability.