Responses of Six Wildflower Species to Seed Matric Priming

Abstract

Seeds of six wildflower species [ Aster novae-angliae (New England aster), Rudbeckia hirta (Black-eyed Susan), Liatris spicata (Blazing star), Hesperis natronalis (Dame's rocket), Gaillardia aristata (Perennial gaillardia), and Asclepias tuberosa (Butterfly weed)] were matrically primed in fine, exfoliated vermiculite. Seeds were primed for 7 days at 15C (59F) at an initial matric potential of−0.5 MPa (−5 bars) in darkness, then dried for 7 days before sowing. A seed: vermiculite (1:2 by wt) ratio was found to be the most appropriate of several ratios because it increased germination rate of all species except Black-eyed Susan, increased the germination percentage of Perennial gaillardia, and prevented germination of Dame's rocket and Perennial gaillardia during priming. Under restricted water availability [−0.25 and−0.50 MPa (−2.5 and−5.0 bars)] priming increased the germination percentage of Perennial gaillardia and Butterfly weed and increased the germination rate of all species. In a glasshouse study, priming increased the emergence percentage of Perennial gaillardia and increased the emergence rate of all species. Compared with hydration of the vermiculite with water, using 10 −3 M gibberellic acid during priming increased the emergence rate of Dame's rocket, increased the emergence percentage of Perennial gaillardia, and increased the shoot dry weights of New England aster and Black-eyed Susan.