PARENT SESSION
Poster Session 36: Genetics / Population Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Increased seed age negatively affects seedling performance and seed viability in white campion (Silene latfolia).
Budischak, Sarah1, Peroni, Patriicia*,, Ripperton, Jonathan, 1 Davidson College, Davidson, NC, USA
ABSTRACT- In order for seed banks to be an effective evolutionary strategy, seeds must not only remain viable, but also must be able to germinate, grow, and compete against conspecifics and other competitors after years of burial. Using white campion (Silene latifolia), a dioecious perennial that maintains a dormant seed bank, as a model species, we examined how age affected the viability and germination rates of seeds and the performance of seedlings. Seeds for this study were collected annually over a 10 yr period from populations in a metapopulation located in southwestern Virginia and stored dry under laboratory conditions. In a growth chamber trial, we found significantly decreased and delayed germination associated with older seeds in 3 of the 4 populations studied. Some seeds remained viable after 11 years, but percent viability as a function of age varied among populations. In a separate experiment, we measured seedling performance as a function of seed age for samples from three of the populations. Upon germination in the growth chamber, we planted the seeds in the greenhouse and measured variables associated with developmental rate and seedling size to assess seedling performance. Seedlings that originated from younger seeds emerged and produced true leaves significantly earlier than seedlings from older seeds. Seedlings from older seeds also produced significantly smaller leaves than those from younger seeds. The decreased and delayed initial growth of seedlings from older seeds may put them at a competitive disadvantage relative to those from younger seeds.
Key words: seed bank, seed age, seedling performance, seedling growth