Contrasting Morphological and Anatomical Traits Among Leaves, Stems, and Roots Between Hemiepiphytic (H) Versus Nonhemiepiphytic (NH) Ficus Species

Abstract

Rising temperatures and fluctuating water availability are influencing plant adaptation and survival. As a special growth form, hemiepiphytic plants may have unique adaptations to their stressful habitats. Ficus species are vital in tropical and subtropical forests with well-known contrasting hemiepiphytic (H) and nonhemiepiphytic (NH) growth forms. Although H and NH Ficus species were found differing in resource acquisition and drought tolerance, this hypothesis has never been tested on root traits. Here we measured 29 morphological and anatomical traits of leaves, stems, and roots of five H and five NH Ficus species. We found that H species exhibited smaller but thicker leaves, higher leaf mass per area, and leaf dry matter content, which enhances water retention. They also had higher wood density and root density, prioritizing tolerance under drought-prone environments. On the other hand, NH species displayed larger leaf areas, higher stomatal density, greater specific root length, and specific surface area, optimizing for growth in resource-rich environments. While NH species capitalize on high-connectivity networks to maximize resource acquisition, H species leverage low-connectivity networks with greater root trait connectivity, indicating flexible responses to stressful habitats. This study highlights the contrasting potential of drought tolerance of H and NH Ficus species through morphological and anatomical traits, showing a consistent adaptive pattern between above- and belowground organs.