Leaf and Root Functional Traits of Woody and Herbaceous Halophytes and Their Adaptations in the Yellow River Delta.

Leaves and roots perform assimilation, supporting plant growth and functionality. The variations in their functional traits reflect adaptive responses to environmental conditions, yet limited information is available regarding these trait variations and their coordination in saline environments. In this study, 18 common woody and herbaceous halophyte species from the Yellow River Delta were collected, and their leaf and root functional traits were assessed and compared. Our results showed that, compared with herbaceous species, woody species had greater root diameter, cortex thickness, and stele diameter, but lower specific root length and leaf area. Meanwhile, root diameter was strongly correlated with cortex thickness and stele diameter; leaf thickness was also tightly related with palisade tissue thickness. However, fewer correlations were found between paired leaf and root traits in either herbaceous or woody species, indicating that the variations in leaves and roots appeared relatively independent, which might be related to the different abiotic environmental conditions experienced by above- and belowground organs. These results highlight that woody species tended to be more conservative in resource acquisition and establishment; meanwhile, the herbaceous ones were acquisitive. Such patterns show the contrasting survival strategies of different plant taxa, which also provide valuable insights for future vegetation restoration efforts in this salinized region.