Oral Paper

         Symbioses: Plant, Animal, and Microbe Interactions

Impacts of temperature and fur texture on the adherence of mucilaginous seeds

Presenting Author
Elizabeth Waring
Description
Within the epidermal tissues of some species of seeds, a polysaccharide substance called mucilage is formed. In mature seeds this mucilage often remains dehydrated. However, mucilage is readily rehydrated when it encounters water.  Although nonvisible when dehydrated, mucilage that is water imbibed becomes a sticky, gel like substance. Not only is hydrated mucilage sticky and adhesive but as mucilage dehydrates it cements the seed to its current surface. As a result of adhering to surfaces, mucilaginous seeds often attach to animals and are dispersed over various distances. Dispersal of seeds to sites where they are able to germinate is an important process in continuing ecological succession because it brings plant growth to new areas.  Zoochrous dispersal of seeds is directly related to the different traits of both plants and animals. Seed morphology has an effect on the adhesiveness to fur and feathers but fur types and feather types also has an effect on the adhesiveness of seeds. Additionally, the temperature of the surface can affect how strongly the now-dried mucilage attaches the seed to the surface. This talk will address two experiments. One looking at how mucilaginous seeds, from 5 different plant families, attachment is impacted by the temperature of the surface and one looking at the force needed to remove attached seeds from animals. In the first experiment, we hypothesized that the seeds on hotter tiles would require less force to remove because the mucilage would dry quicker. This was done using white and black tiles were placed in the shade or sun and the temperature of the tiles was measured. The seeds were then imbibed, placed on the tiles and positioned back into the sun or shade. After the seeds dried, the force to remove them was measured. The findings revealed the hotter surfaces required a lower amount of force to remove the seeds than the cooler tiles, which corresponds to our hypothesis. The data shows that the mucilage drying too rapidly causes the seeds to attach with less strength. In the second experiment, we investigated: (1) The effect of different mucilaginous seeds adhering to animals. (2) How mucilaginous seeds adhere to different species of animals. This study contributes to a better understanding of how mucilage contributes to epizoochory dispersal by showing how mucilage attaches seeds to animals. To determine if the type of mucilaginous seed affected the force needed to remove the seed from animal feathers and fur,we chose multiple different species of seeds.  We also chose five different species of animal, including mammals and waterfowl, to place the seeds upon. We used animal pelts and feathers for each type of specimen. The seeds were left to dry on the animal specimens for at least two hours and the amount of force to remove them was measured. Our research indicates that mucilage enhances seed's ability to adhere to animals, particularly mammals. These results suggest that mucilage plays a key role in epizoochory seed dispersal.