Osmotic Priming or Chilling Stratification Improves Seed Germination of Purple Coneflower

Abstract

<jats:p>High germination seed lots of purple coneflower [<jats:italic>Echinacea purpurea</jats:italic> (L.) Moench] were evaluated for laboratory germination following osmotic priming or chilling stratification. Compared to nontreated seeds, osmotic priming at 25C in salts (KNO<jats:sub>3</jats:sub> + K<jats:sub>3</jats:sub>PO<jats:sub>4</jats:sub>; 1:1, w/w) or polyethylene glycol 4000 (PEG) increased early (3-day) germination percentage at 27C of all seed lots, and improved total (10-day) germination percentage of low-germination seed lots. Total germination percentage was unaffected or increased by priming for 4 days compared to 8 days, and by priming at –1.0 MPa compared to –0.5 MPa (except for one low-germination seed lot). Chilling stratification in water at 5 or 10C increased early and total germination of all seed lots, except for that same lot, compared to nontreated seeds. Total germination percentage was unaffected or increased by stratification at 10C rather than at 5C. Neither extending stratification ≥20 days nor lowering osmotic potential with PEG during stratification improved total germination percentage.</jats:p>

Comparison of prechilling stratification and sulfuric acid scarification on seed germination of Panicum virgatum under drought stress

“…Furthermore, prechilling stratification and sulfuric acid scarification were not found to give improvement in root and shoot growth (Table 1). Prechilling stratification can break seed dormancy by changes to physiologic traits [33] , while sulfuric acid scarification can dramatically alter seed coat physical properties, reducing thickness and strength thereby creating a weak area of root emergence [34] . Thus, prechilling stratification and sulfuric acid scarification mainly contribute to breaking seed coat or embryo dormancy, and their effect differs from hydropriming, which has beneficial effects on MGT and root growth because of sufficient water and longer imbibition time [27] .…”

Impact of Temperature on Seed Dormancy

“…For example, in purple coneflower [Echinacea purpurea (L.) Moench.] germination percentage and rate of emergence were improved in five of six seed lots by a 10-d treatment of either 5 or 10 °C (Wartidininghsih and Geneve, 1994).…”

Reduction of seed dormancy in Echinacea pallida (Nutt.) Nutt. by in-dark seed selection and breeding

“…Development of protocols to improve Echinacea seed germination has been extensive, involving the use of inorganic salts (Gao et al, 1998), growth regulators (Bishnoi et al, 2010; Pill and Haynes, 1996; Qu et al, 2004), cold, moist stratification (Bishnoi et al, 2010; Bratcher et al, 1993; Parmenter, 1996; Qu et al, 2004, Romero et al, 2005; Wartidiningsih et al, 1994) and mechanical scarification (Bishnoi et al, 2010; Feghahati and Reese, 1994; Sorenson and Holden, 1974). Without such treatments, Echinacea seeds (except for some commercial seed lots of E. purpurea ) tend to germinate poorly and/or erratically.…”

“…Organic field production is favored for botanical dietary supplements, and trends towards organic production have been increasing. Of methods that do not involve synthetic chemicals, cold, moist stratification is time consuming, requiring several weeks under controlled conditions, and results have been uneven (Bratcher et al, 1993; Parmenter, 1996; Qu et al, 2004, Romero et al, 2005; Wartidiningsih et al, 1994). Light is another factor that can be effective in promoting Echinacea seed germination (Feghahati and Reese, 1994; Smith-Jochum and Albrecht, 1987), and has been used both during and following cold, moist stratification (Romero et al, 2005).…”