Schematic diagram showing correlations among four traits examined in this study. Yellow and green dots represent EO SN and SO-3 SN, respectively. Red arrows indicate significant positive correlations (denoted by "+"), shown in this study and previous studies . The statistics of positive correlation between EO SN and SO-3 SN were r = 0.24, P < 0.001, n = 247. Black arrows with dotted lines indicate significant negative correlations (denoted by "-") determined in the present study.