Location: Vegetable ResearchTitle: Emergence timing and fitness consequences of variation in seed oil composition in Arabidopsis thaliana
|LINDER, C - University Of Texas|
Submitted to: Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2014
Publication Date: 1/1/2015
Publication URL: http://onlinelibrary.wiley.com/doi/10.1002/ece3.1265/full
Citation: Pelc, S., Linder, C.R. 2015. Emergence timing and fitness consequences of variation in seed oil composition in Arabidopsis thaliana. Ecology and Evolution. 5(1): 164–171.
Interpretive Summary: Timing of germination and seedling emergence can contribute significantly to the overall lifetime fitness of plants, particularly annuals. Seed oil composition (the types and relative amounts of fatty acids in the oils) may play an important role in determining germination timing and emergence for the 80% of flowering plants that store oils for energy in their seeds. An ARS scientist in Charleston, SC, in collaboration with a scientist at the University of Texas at Austin, TX investigated the impact of temperature on time to first emergence in plants with disparate seed oil melting points and measured relative fitness. Plants with higher saturated fatty acid levels had more total energy and as a result, higher relative fitness. Understanding the relationship between seed oil composition, emergence timing, and fitness is an important consideration for scientists working in the public and private sectors to alter oilseeds for industrial and agricultural uses.
Technical Abstract: Early seedling emergence can increase plant fitness under competition. Seed oil composition (the types and relative amounts of fatty acids in the oils) may play an important role in determining emergence timing in oilseeds. Saturated fatty acids provide more energy per carbon atom than unsaturated fatty acids but have substantially higher melting points (when chain length is held constant). This characteristic forms the basis of an adaptive hypothesis that low melting point seeds (low proportion of saturated fatty acids) should be favored under colder germination temperatures due to earlier germination and faster growth before photosynthesis, while at warmer germination temperatures seeds with a higher amount of energy (high proportion of saturated fatty acids) should be favored. To assess the effects of seed oil melting point on timing of seedling emergence and fitness, high and low melting point lines from a recombinant inbred cross of Arabidopsis thaliana were competed in a fully factorial experiment at warm and cold temperatures with two different density treatments. Emergence timing between these lines was not significantly different at either temperature, which aligned with warm temperature predictions but not cold temperature predictions. Under all conditions, plants competing against high melting point lines had lower fitness relative to those against low melting point lines, which matched expectations for undifferentiated emergence times.