Abstract: Interactions among roots and leaves are fundamental for plant growth and survival, yet there remains a knowledge gap in mangrove plants that experience saline stress distinct from most other vascular plants hereafter the non-mangroves. Here, we explored the coordination of above- and below-ground trait relationships among mangrove species in tropical China and compared it with those of non-mangroves. Our results show that root stele, the water-conducting tissue, was coupled with leaf water use traits and tissues outside the stele (ToS), the carbon-consuming tissues in roots, were independent of leaf economics traits in non-mangroves. However, in mangroves, root stele is independent of leaf water use traits and root ToS is coupled with leaf economics traits. The contrasting root–leaf coordination between mangroves and non-mangroves potentially arises from the existence of leaf water storage tissues in mangroves and the universal allometric relationship between root stele and ToS in both plant groups. Our findings pave a new way for understanding the ecology and vegetation dynamics of mangrove and non-mangrove plants under global environmental change.

Key words: leaf water use traits, leaf economics traits, root traits, leaf water storage tissues, allometry, mangrove and non-mangrove plants