Figure Legends
Fig. 1. Distribution of sampling sites and hypothesis of hypocotyl dispersal status. A, Sampling sites of Kandelia obovata hypocotyl on the south coast of China. The color gradient indicates the salinity (‰) of surface seawater. Circle size is proportional to genealogies size (N). See Table S1 for a detailed description of field sites. B, Determination of hypocotyl traits: length, maximum transverse diameter (TDmax) and minimum transverse diameter (TDmin). C, The hypothesis of different ratio of TDmax to TDmin (RTD) of hypocotyl have different positions relative to the water surface while floating and illustration of the linkage of RTD and tradeoff between dispersal and retention.
Fig. 2. Principal component analysis (PCA) of hypocotyl traits. FW, fresh weight; FL, fresh length; TDmax, maximum transverse diameter; TDmin, minimum transverse diameter; RTD, ratio of TDmax to TDmin.
Fig. 3. Patterns of hypocotyl intraspecies traits variations (ITV) along latitudinal gradients.A, Relationship between PC1 and latitude. B, Relationship between RTD and latitude. Bule line is ordinary least-squares linear regression (OLR), and red line is quadratic regression (QR). Solid line indicates statistical significance (P < 0.05), dashed line indicates statistical non-significance (P> 0.05). Filled area means SE. PC1, the first principal component. RTD, ratio of TDmax to TDmin.
Fig. 4. Sources of hypocotyl intraspecies traits variations (ITV). A, E, Variance partitioning of PC1 and RTD across three nested levels of organization.B, F, Summary of the linear mixed-effect modeling for multiple biotic and abiotic factors on PC1 and RTD. Data are presented as coefficients ± standard errors of the estimated effect sizes.R 2m represents marginalR 2, R 2c represents conditional R 2. *, P < 0.05; ***, P < 0.001. C, D, G, H, The relationships between significant biotic and abiotic factors and PC1 and RTD. Bule line is ordinary least-squares linear regression (OLR), and red line is quadratic regression (QR). Filled area means SE. SAL, sea surface salinity; MAT, mean annual temperature; MAP, mean annual precipitation; AFC, annual fastest tide current; ALT, annual lowest tide; AGB, aboveground biomass. PC1, the first principal component. RTD, ratio of TDmax to TDmin.
Fig. 5. Direct and indirect effects of biotic and abiotic factors on hypocotyl intraspecies traits variations (ITV). A, C, Structural equation models (SEMs) showing the relationships among biotic, abiotic factors and PC1 and RTD.B, D, Standardized effects derived from SEMs of PC1 and RTD. Red and black arrows indicate positive and negative relationships, respectively. Solid or dashed lines indicate significant (P< 0.05) or non-significant relationships. Numbers near the pathway arrow indicate the standard path coefficients.R 2 represents the proportion of variance explained. The relevant indicators are abbreviated as: PC1, the first principal component; RTD, ratio of TDmax to TDmin; AGB, aboveground biomass; SAL, sea surface salinity; AFC, annual fastest tide current; ALT, annual lowest tide; MAT, mean annual temperature; MAP, mean annual precipitation.
Figure 1