EAPSI: The Evolutionary Ecology of Seed Mucilage in Plantago Species

Elwood Elise C, Davis CA

Investigators

Abstract

As the globe is warming and rainfall is less predictable, it is important to determine the traits that allow plants to cope with increased water stress. Some seeds can produce a gelatinous covering many times the size of the seed that expands when the seed gets wet. This functional trait, known as mucilage, may be an important way plants deal with stressful environments--for instance, by increasing seed germination percentage and seedling establishment in conditions of water stress--yet little is known about the trait This study will compare seeds from Plantago lanceolata, known as common plantain, that experience different habitat across the globe. The researcher will determine the frequency of this trait in dry habitats, its effect on seed germination, plant growth, and plant success under low and unpredictable water availability. This research will be conducted in collaboration with Dr. Zhenying Huang, an expert on seed mucilage at the Chinese Academy of Sciences in Beijing and the Central Mongolian Field Station. Seed mucilage (myxospermy) is found in 230 genera of angiosperms and has been demonstrated to serve a variety of ecological functions including aid in dispersal and germination. There is a trade-off between seed number per fruit and mucilage in P. coronopus along a latitudinal gradient, suggesting that seed mucilage may be costly to produce and mitigate stressful environments (increased temperature and reduced precipitation). The researcher will use a common garden experiment to conduct an intraspecific study on myxospermy in P. lanceolata, a perennial species with a global distribution. The researcher will ask if seed mucilage increases germination and establishment of P. lanceolata under low and high osmotic stress. Through comparison of spatially dispersed populations, the researcher will determine whether seed mucilage production differs along a temperature or precipitation gradient. The researcher predicts that the seed to mucilage ratio will be greater in arid and highly stochastic environments where buffering may be needed. Another prediction is that seed mucilage will improve fitness when seeds are exposed to osmotic stress. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Chinese Ministry of Science and Technology.