2.5 Statistical analysis of the results
The Kruskal-Wallis H-test and Mann-Whitney U-test values are shown in
Supplementary Table 11. In this study, only SSRs in the chloroplast
genome in its IGS and LSC regions, as well as single-nucleotide SSRs in
the whole chloroplast genome, were considered. There were significant
differences in the number, relative abundance, relative density, and GC
content of SSRs when the eight species of Cyatheaceae were divided into
three genera (Kruskal-Wallis H, P < 0.05). WhenGymnosphaera was included in the genus Alsophila , they
were divided into two genera, and only the difference in the GC content
was significant (Table 4). The number of SSRs in other regions of the
chloroplast genome and the number of SSRs of other unit lengths were
small, so they are not discussed in this study. The clustering results
of the number, relative abundance, relative density, and GC content of
the SSRs in the chloroplast genomes and their IGS regions and the
single-nucleotide SSRs of the whole chloroplast genome of the eight
species of Cyatheaceae (Figure 5) showed that the eight species were
divided into two groups. That is, Sphaeropteris brunoniana ,Sphaeropteris lepifera , Alsophila spinulosa andAlsophila costularis were in a group, and Alsophila
denticulata , Alsophila podophylla , Alsophila metteniana ,
and Alsophila gigantea were in a group.
Table 4 Significance test of the number, relative abundance, relative
density, and GC content of SSRs in the whole chloroplast genome, IGS,
and LSC and mononucleotide SSRs in the whole chloroplast genome of the
eight Cyatheaceae species