The effects of stratification, BA, thiourea, and GA3 were examined on germination of Liatris spicata (L.) Willd. seed. Seeds were germinated at 20 °C and numbers of germinated seed were counted daily for 21 days. The final germination percentage (G) for seeds stored dry at 4 °C for 0 to 10 weeks ranged from 52% to 64%, while stratification at 4 °C for 10 weeks increased G to 98% and decreased the days to 50% of final germination (T50) and the days between 10% and 90% germination (T90-T10). Aqueous solutions of BA at 10 or 100 mg·L-1 applied to blotter paper increased G and decreased T50 but did not affect T90-T10. In a separate experiment, dry seeds were treated for 3 minutes in BA at 0 to 1126 mg·L-1 dissolved in acetone. G values increased quadratically, whereas T50 and T90-T10 values decreased quadratically in response to BA concentration. A 3-minute preplant acetone permeation of seeds with BA at 225 or 1127 mg·L-1 yielded G and T50 values similar to those obtained with 10 weeks of stratification. Seeds immersed in thiourea at 0.76 or 7.61 mg·L-1 for 24 hours prior to sowing had higher G and lower T50 values than controls (0 mg·L-1 thiourea), but T90-T10 values were similar for all treatments. Seeds treated with GA3 at 1, 10, or 100 mg·L-1 in H2O did not differ from controls (0 mg·L-1 GA3) in G, T50, or T90-T10. Infusion of BA via acetone may be a practical means of breaking seed dormancy and accelerating germination in L. spicata. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine [benzyladenine (BA)]; gibberellic acid (GA3); thiocarbamide (thiourea).
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