关键词: 系统发育树, 根瘤菌, 16S rDNA, nifH, 豆科植物, 喀斯特

Abstract: Seed dispersal is essential to the reproduction, distribution, and evolution of plants. To study the correlations of plant seed dispersal pattern with genome size and 1000-seed mass is of significance for revealing the invasion of plant seeds and the mechanisms of genome evolution. In this paper, statistics and correlation analysis were conducted on 235 plant species with complete genome information (chromosomes number, ploidy, and C-value), 1000-seed mass, and seed dispersal patterns, based on the previous estimation of some plant species C-values and the searching of plant C-value database and seed information database. The ANOVA analysis indicated that for the plants whose seeds were dispersed by water, bird, and wind, the C-values (C_water=1.3 pg, C_bird=1.6 pg, and C_wind=2.0 pg) and genome sizes (1Cx_water=1.1 pg, 1Cx_bird=1.3 pg, and 1Cx_wind=1.6 pg) were significantly lower than those whose seeds were dispersed by animaleating (1C_animal=4.9 pg, and 1Cx_animal=4.7 pg) (P<0.05), but no significant differences were observed among the four dispersal patterns and the unassisted dispersal and animalcarrying patterns (P> 0.05). The 1000-seed mass of the 235 species varied greatly. The 1000-seed mass of the plants with seed dispersal by wind and animalcarrying (7.2 g and 13.5 g, respectively) were obviously lower than that with seed dispersal by water and animaleating (85.8 g and 92.5 g, respectively), but the 1000-seed mass of the plants with unassisted dispersal had no significant differences with that of other dispersal patterns. The further correlation analysis showed that there existed positive correlations between the genome size and 1000-seed mass of the plants whose seeds were dispersed by animaleating and water (γ=0.33), in which, the correlation for the plants whose seeds were dispersed by animal-eating was significant (y=0.67x+3.23, R²=0.11,P=0.04). These findings would provide references to reveal the mechanisms of plant seed dispersal, distribution, and genome evolution.

Key words: phylogenetic tree, rhizobia, 16S rDNA, nifH, legume, Karst.