Stomatal distribution pattern for 90 species in Loess Plateau-Based on replicated spatial analysis

Stomata are the valves controlling carbon and water exchange between plant leaves and the atmosphere. Stomatal position changes throughout the whole growth of leaves, and the position is gradually fixed until the leaves mature, whether stomatal spatial distributions exhibit clear patterning remains unclear. In this study, we measured stomatal density and stomatal position of 90 widespread plants from the Loess Plateau, quantifying the spatial patterns of stomatal distribution using replicated spatial point pattern analysis. The results showed that the stomatal distribution pattern was similar in all plants except five species (Ginkgo biloba, Festuca glauca, Hemerocallis fulva, Hylotelephium spectabile and Kochia scoparia). Stomatal density, aggregation and uniform distribution were slightly affected by phylogeny and depended on spatial scale of analysis. At small spatial scales (0-60 mu m), were regularly distributed but at large spatial scales (60-400 mu m) they were randomly distributed. Stomatal density was negatively correlated (p < 0.001) with the proportion of randomly distributed and positively correlated (p < 0.001) with the proportion of stomatal aggregated distributed, and no significant effect on the proportion of stomatal uniform distribution. These results highlight the linkages between stomatal distribution and phylogeny, which may provide reference for future optimization of transpiration models.