Shiba Masayuki, Fukuda Tatsuya
Graduate School of Integrative Science and Engineering, Tokyo City University, Tokyo, Japan.
Sci Rep. 2025 Aug 13;15(1):29664. doi: 10.1038/s41598-025-15715-0.
Riparian environments are unique habitats highly susceptible to sudden flooding following heavy rainfall. In such conditions, the sterile in dimorphic fronds that remain aboveground for several months have adapted to thrive by developing linear and lanceolate laminae supported by robust yet flexible petioles. However, it remains unclear whether fertile fronds, which develop only for a short period of several days to weeks, exhibit similar adaptations. To address this question, we conducted morphological, anatomical, and mechanical analyses of the stipes of Osmunda lancea (Osmundaceae), which inhabits riversides, and its inland sister species O. japonica. Our results revealed that the stipes of O. lancea were more flexible than those of O. japonica, accompanied by a reduction in cell length within the sterome. Furthermore, the sterome of the stipe was found to be composed of thin-walled cells, enabling the formation of the stipe at a low carbon cost within a short period and facilitating spore dispersal.
河岸环境是独特的栖息地，极易在暴雨后遭受突然的洪水。在这种情况下，在地面上留存数月的二形叶不育叶通过发育由粗壮但柔韧的叶柄支撑的线性和披针形叶片来适应并茁壮成长。然而，尚不清楚仅在短短几天到几周内发育的可育叶是否表现出类似的适应性。为了解决这个问题，我们对生长在河边的披针蕨（紫萁科）及其内陆近缘物种日本紫萁的叶柄进行了形态学、解剖学和力学分析。我们的结果表明，披针蕨的叶柄比日本紫萁的叶柄更柔韧，同时其厚壁组织内的细胞长度有所缩短。此外，发现叶柄的厚壁组织由薄壁细胞组成，这使得叶柄能够在短时间内以低成本的碳形成，并有利于孢子传播。
