Document: PET-3-37-4

The influence of salinity and maternal environment on germination in Iris Hexagona.

VAN ZANDT, P.A.* and S.MOPPER

University of Louisiana at Lafayette ¹

Abstract:
Whether a seed germinates and becomes established has important implications for the distribution of a plant species. A general paradigm in wetland plant communities is that perennial salt marsh species spread mainly by vegetative propagation, and that flowering and subsequent establishment of seedlings is rare. In salt marshes, salinity may act directly by decreasing germination rates as well as indirectly by altering seed provisioning from the maternal plant. Because salinity levels in salt marsh environments are frequently correlated between plant generations, maternal effects might be both strong and adaptive. We examined both the direct and indirect (maternal) effect of salinity on seed germination rates of Iris hexagona, a perennial found in fresh and brackish marshes in the southeastern U.S. We obtained 5616 seeds from hand and bee pollinations of plants maintained in three salinity levels (0, 2, and 4 ppt), and planted them in a greenhouse at one of four salinity treatments (0, 3, 6, and 9 ppt). We found that seeds planted in elevated salinity experienced a direct abiotic effect, which significantly reduced both germination rate and number. However, salinity also stimulated seed germination via an indirect, maternal effect: Seeds from plants growing in high salinity germinated faster and at greater number than seeds from low salinity treatment plants.

Keywords: maternal effects, germination, salinity stress, Iris hexagona

This abstract is being presented at: 4:15 PM in session:
Oral Session #33: Plant Demography.