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Loren C. Stephens

Echinacea purpurea is one of several native Echinacea species of the American Great Plains; indeed, wild populations still exist in undisturbed remnants of that ecosystem ( McKeown, 1999 ). American Indians used Echinacea angustifolia DC

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Qingling Li, Yuesheng Yang, and Hong Wu

Echinacea purpurea is an important herbaceous plant primarily native to North America ( McGregor, 1968 ) and has received considerable attention for its ornamental and medicinal value in recent years. E. purpurea has long been a popular

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Anatoli Dzhurmanski, Kana Varbanova, and Valtcho Zheljazkov

Common coneflower (Echinacea purpurea) is used as medicinal, cutflower, or ornamental plant. There is significant diversity and chemotypes within the species. Flower morphology and shape has been shown to affect fertilization and, subsequently, seed formation and yields, and seed germination. The aim of this study was to describe morphological and biological characteristics of locally available Echninacea seed progeny and evaluate segregating populations in F1. Overall, the F1 seed progeny of Echinacea purpurea was clustered into three different groups with distinct morphological characteristics and ornamental qualities: 1) plants having tubular type of flowers, 38.9% of all plants; 2) plants with flat flowers; and 3) plants with cone-shaped flowers. The latter is the most commonly found type. We found that 11% of all Echninacea plants would fail to have seed set. However, 55% of Echninacea plants with tubular (spherical) flowers would be without seeds. Of the plants with tubular flowers, 40% were with tubules longer than 10 mm. The plants from the F2 and F3 progenies were with very low seed productivity, with greater variation of morphological characteristics, and some of them with characteristics not found in F1. Several promising forms with potentially high ornamental value were identified.

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Sara Michele Wills and Gary R. Bachman

Vermicompost or worm-worked wastes have been reported to enhance seedling germination and growth during plug production. The objective of this project was to examine the effects of vermicompost on germination of a herbaceous perennial having varying viability in coir-based container media. Seeds of Echinacea purpurea (Purple Coneflower) collected from field-grown plants in 1998 and 1999 were considered low- and medium-viability seeds, respectively. A third group of seeds was purchased from a major seed company and was considered to have high viability due to optimal storage conditions. “Ragdoll” germination tests resulted in the following viability ratings: low (1%), 1998; medium (67%), 1999; and high (79%), purchased seed. The three sources of seed were planted into coir-based media. Vermicompost was incorporated into the media at 10% by volume. The control media did not have vermicompost added. Twelve days after project initiation seeds sown into media containing vermicompost had 73% and 90% greater germination than control media for the 1999 and purchased seed. At the project conclusion, 24 days after initiation, seeds sown into media containing vermicompost had 23% and 42% greater germination than the controls for the 1999 and purchased seed. The 1998 seed had 5% germination after 24 days compared to 1% for the control. The addition of vermicompost could be used as a method to increase germination rate and percentage of seeds having lower viability.

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Qudsia Hussaini, Chiwon W. Lee, and Shanqiang Ke

Leaf sections of Echinacea purpurea obtained from greenhouse-grown plants were cultured on Murashige and Skoog (MS) medium supplemented with 0.5 to 4.0 μM benzyladenine (BA) and 0.1 to 10.0 μM naphthaleneacetic acid (NAA). The efficiency of adventitious shoot formation from leaf explants varied depending on growth regulator concentrations. About 90% of leaf tissues cultured with 20 μM BA and 0.1 μM NAA produced shoot differentiation. Initially, the adventitious shoot buds were purplish-red in color; they turned to green shoots as young leaves began to unfold. The individual shoots, when excised and subcultured on the MS basal medium containing 10 μM gibberellic acid (GA3), produced 15 to 20 new shoots per culture within 4 weeks.

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Ki Sun Kim, Art Cameron, and Erik S. Runkle

Echinacea purpurea Moench., or purple coneflower, has been classified both as an intermediate-day plant and a short-day/long-day plant by different research groups. We performed experiments to determine at what developmental stage Echinacea`Magnus' became sensitive to inductive photoperiods, and identified photoperiods that induced the most rapid flowering. Seedlings were raised under continuous light in 128-cell plug trays, then were transplanted into 11.4-cm plastic pots. Plants were transferred to 10-hour short days (sd) once seedlings developed 3, 4, 5, 6, 7, or 8 true leaves. After 4 or 6 weeks of sd treatment (primary induction), plants were moved to 16- or 24-hour photoperiods until flowering (secondary induction). Plants were also grown under continuous 10-, 14-, and 24-hour photoperiods to serve as controls. At least 4 leaves were required for flower induction; flowering was delayed and the percentage was low when plants had 3 leaves at the beginning of primary induction. Plants under continuous 14-hour photoperiods had the highest flower percentage (100%) and flowered earliest (87 days). Plants under continuous 10- and 24-hour photoperiods did not flower. Four weeks of sd followed by 16-hour photoperiods induced complete flowering and in an average of 95 days. However, 6 weeks sd was required for 100% flowering when the final photoperiod was 24 hours.

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Luping Qu, Xiping Wang, Ying Chen, Richard Scalzo, Mark P. Widrlechner, Jeanine M. Davis, and James F. Hancock

Seed germination patterns were studied in Echinacea purpurea (L.) Moench grouped by seed source, one group of seven lots from commercially cultivated populations and a second group of nine lots regenerated from ex situ conserved wild populations. Germination tests were conducted in a growth chamber in light (40 μmol·m–2·s–1) or darkness at 25 °C for 20 days after soaking the seeds in water for 10 minutes. Except for two seed lots from wild populations, better germination was observed for commercially cultivated populations in light (90% mean among seed lots, ranging from 82% to 95%) and in darkness (88% mean among seed lots, ranging from 82% to 97%) than for wild populations in light (56% mean among seed lots, ranging from 9% to 92%) or in darkness (37% mean among seed lots, ranging from 4% to 78%). No germination difference was measured between treatments in light and darkness in the commercially cultivated populations, but significant differences were noted for treatments among wild populations. These results suggest that repeated cycles of sowing seeds during cultivation without treatments for dormancy release resulted in reduced seed dormancy in E. purpurea.

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Erik S. Runkle, Royal D. Heins, Arthur C. Cameron, and William H. Carlson

Intermediate-day plants (IDP) flower most rapidly and completely under intermediate photoperiods (e.g., 12 to 14 h of light), but few species have been identified and their flowering responses are not well understood. A variety of experiments was conducted to determine how light controls flowering and stem extension of Echinacea purpurea `Bravado' and `Magnus'. Both cultivars flowered most completely (79%) and rapidly and at the youngest physiological age under intermediate photoperiods of 13 to 15 h. Few (14%) plants flowered under 10- or 24-h photoperiods, indicating E. purpurea is a qualitative IDP. Plants were also induced to flower when 15-h dark periods were interrupted with as few as 7.5 min of low-intensity lighting (night interruption, NI). Flowering was progressively earlier as the NI increased to 1 h, but was delayed when the NI was extended to 4 h. Stem length increased by 230% as the photoperiod or NI duration increased, until plants received a saturating duration (at 14 h or 1 h, respectively). At macroscopic visible bud, transferring plants from long days to short days reduced stem extension by up to 30%. Flowering was inhibited when the entire photoperiod was deficient in blue or red light and was promoted in a far-red deficient environment, suggesting that phytochrome and cryptochrome control flowering of E. purpurea. Because of our results, we propose the flowering behavior of IDP such as E. purpurea is composed of two mechanisms: a dark-dependent response in which flowering is promoted by a short night, and a light-dependent response in which flowering is inhibited by a long day.

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Luping Qu, Ying Chen, Xiping Wang, Richard Scalzo, and Jeanine M. Davis

We investigated patterns of variation in alkamides and cichoric acid accumulation in the roots and aboveground parts of Echinacea purpurea (L.) Moench. These phytochemicals were extracted from fresh plant parts with 60% ethanol and quantified by high performance liquid chromatography (HPLC) analysis. Concentrations of alkamides and cichoric acid were measured on a dry-weight basis (mg·g–1). For total alkamides, concentrations among individual plants varied from 5.02 to 27.67 (mean = 14.4%) in roots, from 0.62 to 3.42 (mean = 1.54) in nearly matured seed heads (NMSH), and 0.22 to 5.25 (mean = 0.77) in young tops (about ½ flower heads, ¼ leaves, and ¼ stems). For cichoric acid, concentrations among individual plants varied from 2.65 to 37.52 (mean = 8.95), from 2.03 to 31.58 (mean = 10.9), and from 4.79 to 38.55 (mean = 18.88) in the roots, the NMSH, and the tops, respectively. Dodeca-2E, 4E, 8Z, 10E-tetraenoic acid isobutylamide and dodeca-2E, 4E, 8Z, 10Z-tetraenoic acid isobutylamide (alkamides 8/9) accounted for only 9.5% of the total alkamides in roots, but comprised 87.9% in the NMSH, and 76.6% in the young tops. Correlations of concentrations of alkamides or cichoric acid between those of roots and those of the NMSH were not statistically significant, and either within the roots, the NMSH, and the young tops. However, a significant negative correlation was observed between the concentration of cichoric acid in the roots and in young tops, and a significant positive correlation was observed between total alkamide concentration in the roots and cichoric acid concentration in the young tops. These results may be useful in the genetic improvement of E. purpurea for medicinal use.

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Dina Margaret Samfield, Jayne M. Zajicek, and B. Greg Cobb

Seeds of tickseed (Coreopsis lanceolata L.) and purple coneflower [Echinacea purpureo (L.) Moench] were primed in aerated solutions of a 50 mm potassium phosphate buffer at 16C. C. lanceolata seeds were primed for 3 or 6 days; E. purpurea seeds were primed for 6 or 9 days. Seeds were vacuum-stored for 2 months immediately after priming. Identical treatments were imposed on open-stored seeds just before the termination of the storage duration, thus producing four treatments: a vacuum-stored control, an open-stored control, primed vacuum-stored seed, and seed primed after open storage. Although priming significantly improved the performance of C. lanceolata seed, vacuum storage alone also significantly increased the speed of germination and final germination. The advantage of priming was diminished during 2 months of vacuum storage of E. purpurea, but priming enhanced germination as compared with the open-stored nonprimed control. There was little difference between the performance of E. purpurea seeds both primed and vacuum-stored. and the vacuum-stored control.