2.6. Data analysis
This study calculated the average value of root system architecture
traits for each species, and the trait values for each species were
derived from 10 plant individuals. We calculated the variation
coefficient (CV , Standard error divided by average and multiplied
by 100%) of each root system architecture trait. Blomberg’s Kvalue is used to test phylogenetic signals of various root system
architecture traits(Blomberg et al., 2003). The
ReorderData() function in the evobiR package
was used to rearrange the root system architecture trait data in the
order of the evolutionary tree, and then the phylosig()
function in the phytools package in R 4.2.1 was used to
calculate the Blomberg’s K value, which was set to 999 times
repeatedly (Kraft et al., 2010; Revell, 2012). The pic()
function in the ape package was used to calculate the
Phylogenetic Independent Contrast (PIC) value of each trait
(Felsenstein, 1985; Paradis and Schliep, 2019). The
sma() function of the smatr package was used to
achieve standardized principal axis (SMA) regression analysis that is
used to analyze the correlation between traits. Origin 2021 (Origin Lab
Corporation, Northampton, MA, USA) was used to exert data visualization.