Figure 3 Intraspecific variation coefficients in root system architecture traits of 47 annual ephemerals in the desert of northern Xinjiang, China.
3.2. Phylogenetic signal of root system architecture traits
Phylogenetic signal is also important ecological indicator for detecting the impact of phylogenetic relationship between species on traits. We constructed a phylogenetic tree of annual ephemerals in this study based on the APG IV (Angiosperm Phylogeny Group) plant classification system (Fig. 4). Blomberg’s K values for six root system architecture traits were immediately detected (Table 2). The results showed that theK value of MRD was 0.409, showing a significantly and weakly phylogenetic signal (0<K<1, P<0.05). However, no significantly phylogenetic signals were detected for the other five root system architecture traits (K<1; P>0.05).