Mucilage segregation in diaspores after wetting has been related to different functions but there has not been an approach to the benefit of mucilage as an adherence mechanism under erosive conditions. We want to understand the advantages of mucilage segregation for plants experiencing soil erosion and to establish a quantitative relation between the phenotypic expression and the success of seed adherence. We also aimed to know if changes in erosive conditions influence mucilage segregation in species and the specific composition of plant communities. We related the amount of mucilage segregation with the number of drop impacts needed to remove the seeds under simulated rain in Helianthemum violaceum and Fumana ericifolia (Cistaceae) and measured seed removal distance because water runoff in seeds with and without mucilage of H. violaceum. Also, we compared the amount of seed mucilage segregation of plants living under erosive and non-erosive conditions and the proportion of species with mucilaginous diaspores of Mediterranean semiarid plant communities under those contrasted conditions. The amount of segregated mucilage positively related to longer resisting rain drop impacts in F. ericifolia but not in H. violaceum seeds. However, H. violaceum seeds with intact mucilage layer moved half of the distance because of runoff than those without. Moving from non-erosive to high-erosive sites, near 10% increase in mucilage segregation was found in seeds of F. ericifolia but a decrease of 1% in H. violaceum. Likewise, the presence of species with mucilaginous diaspores increases 9-28% in plant communities living in those contrasted conditions. Mucilage segregation by diaspores is an effective way to reduce seed removal by erosion in plants, even if it operates in different ways depending on the species. Intensification of the exposition of plants to erosive conditions produces a quantitative response in the expression of this mechanism in one of two species tested and at community level.

Poster presentado en el 12th European Ecological Federation Congress celebrado en Ávila del 25 al 29 de septiembre de 2011

Peer Reviewed