Cell Wall Polymers Exert Distinct Effects on Mucilage Architecture and Adhesion to Help Seeds Attach to Substrates

Reforestation efforts are often constrained by low seed survival under harsh environmental conditions due to seed displacement from suitable microsites. Myxospermous seeds produce mucilage that promotes post-dispersal attachment and water retention, thereby enhancing seed establishment. Here, we investigated the biological factors governing mechanical attachment across four myxospermous species, Ocimum basilicum (basil), Salvia hispanica (chia), Plantago ovata (psyllium), and Linum usitatissimum (flax), which occupy diverse ecological environments. We used light-sheet fluorescence microscopy, enzymatic treatments, physical characterization methods, and functional attachment assays to investigate the mechanisms underlying mucilage-mediated seed attachment on heterogeneous surfaces. We found variation among mucilage-mediated seed attachments under applied hydrostatic pressure. Enzymatic treatments revealed that pectin removal causes a marked loss of adhesion across all species. However, psyllium mucilage, which possesses hemicellulosic networks, showed stronger attachment than pectin-rich flax mucilage on rough and porous substrates. Notably, mucilage could be transplanted to non-myxospermous seeds, conferring functional attachment capabilities. Together, our results show that species-specific mucilage properties generate distinct modes of attachment across diverse substrates, driven by differences in polysaccharide composition and fibrillar architecture. These findings link mucilage molecular structure to seed resilience and reveal an adaptive mechanism enabling seeds to persist in heterogeneous environments.