PubMed · 2026-05-26
A study of 26 tropical fern species found that ferns in sunny, open habitats take on more water stress risk at the leaf level but compensate with finer roots and leaner stems, while shade-dwelling ferns play it safer with thicker rhizomes that store water. The findings overturn the assumption that ferns are universally water-conservative.
Light-demanding ferns had higher specific root length (finer, more spread-out roots) and operated closer to their hydraulic failure threshold at the leaf level compared to shade-tolerant species.
Shade-tolerant ferns invested more biomass in rhizomes (underground storage stems), which buffered leaf water potential and provided a larger hydraulic safety margin.
Ferns as a group showed more negative stomatal safety margins than both woody and herbaceous flowering plants, meaning they operate closer to the edge of water stress than most angiosperms.
