Echinacea pallida, one of the three medicinal Echinacea species native to North America, is generally wildcrafted, and low and uneven seed germination are obstacles to its widespread cultivation. Nonstratified E. pallida seeds were treated with 2500, 3500, and 4500 mg/L GA3 to increase seed germination. Treated seeds were directly germinated at 25 °C and 25/15 °C (14/10h) or stored at 5 and 10 °C for 4, 8, and 12 weeks before germination at the same temperatures. Seed germination across treatments was higher at 25 °C (19%) than at 25/15 °C (14%). Application of 2500, 3500, and 4500 mg/L GA3 significantly increased seed germination rate and total seed germination of nonstratified seeds of E. pallida and resulted in 44%, 50%, and 63% total seed germination, respectively, while untreated control seeds germinated at only 9%. The effect of GA3 as a germination stimulant increased with cold storage, with maximum germination (83%) occurring after seeds were treated with 4500 mg/L GA3 and an 8-week cold storage period at 10 °C. The effect of cold storage periods of 4, 8, and 12 weeks and cold storage temperatures of 5 and 10 °C on seed germination were generally similar. Seeds collected from the upper rows of the seed heads germinated significantly higher (10.6%) than those collected from the lowest seed rows (2.4%).
Rapid and timely production of kiwi (Actinidia deliciosa) seedlings is often hampered by poor and erratic seed germination. This investigation was conducted to assess the effect of gibberellic acid, cold stratification (5° C), and their combinations on seed germination and subsequent radicle elongation. Germination counts and radicle elongation measurements were made two weeks after incubation at 25.4° C under continuous light and approximately 100% RH. GA treatments broke dormancy and increased germination and radicle elongation with increasing concentration up to 2500 ppm. At 5000 ppm, germination and radicle elongation were reduced. Cold stratification (1 and 2 week durations) alone did not affect germination nor break dormancy. Combined cold stratification and GA treatments significantly enhanced seed germination and radicle elongation with the best response at the highest GA concentration (5000 ppm) and longest stratification (2 weeks), regardless of whether the seeds were stratified prior to or after GA treatments.
Abstract
Tomato seeds were more responsive than wheat or lettuce seeds to the presence of an inhibitor in the juice of tomato fruits. Seed germination and seedling growth decreased with increasing concentrations of juice. Inhibition of seed germination in 20% juice with an osmotic concentration of less than 0.1 M was significantly less than in 0.1 M glucose or mannitol with 0.01 M citric acid at pH 4.4. The inhibitor in tomato juice was thermostable, but the effect decreased with prolonged storage at -20°C. There were cultivar differences in the amount of inhibitor present in ripe tomato fruits.
Abstract
Seed germination of ‘Royal Mix’ freesia was most rapid and uniform at 15.5° or 18.5°C under clear polyethylene or at 13° or 21.5°C under black polyethylene. Soaking seeds in running water prior to germination or removal of the seed coat did not improve seed germination
This investigation documents the key anatomical features in embryo development of Cypripedium formosanum Hayata, in association with the ability of embryos to germinate in vitro, and examines the effects of culture media and seed pretreatments on seed germination. A better understanding of zygotic embryogenesis for the Cypripedium L. species would provide insights into subsequent germination events and aid in the in vitro propagation of these endangered species. In seeds collected at 60 days after pollination (DAP), soon after fertilization, no germination was recorded. The best overall germination was found at 90 DAP (≈70%), at which time early globular to globular embryos with a single-celled suspensors can be observed. After 135 DAP, the seeds germinated poorly. At this time the inner integument shrinks and forms a tight layer, which encloses the embryo, the so-called “carapace.” Using Nile red stain, a cuticular substance was detected in the carapace, which may play a role in the impermeability of the mature seed and may help the seeds survive in the stringent environment. At maturity (after 210 DAP), the embryo proper has an average size of eight cells along its length and six cells across the width. Lipids and proteins are the main storage products within the embryo. To improve seed germination, experiments were conducted to test the suitability of various media and pretreatments of seeds. When different media were used, except for the Harvais medium at 120 DAP, there was no significant difference in seed germination at three different developmental stages tested. Soaking mature seeds in 1% NaOCl or treating them with ultrasound may slightly increase the germination percentage. For seed germination, our results indicate that the timing of seed collection outweighs the composition of medium and the seed pretreatments.
Germination was evaluated in six seed lots of purple coneflower purchased from four different seed companies. Standard germination percent ranged from 28% to 90% depending on the seed lot. For seed collected in 1989, seed size and stage of development of the seed at harvest could not account for the wide variability in seed germination observed in the purchased seed lots. preconditioning the seed with either cold stratification (10°C for 10 days) or osmotic priming (PEG or salt solution at -5 bars for 5 days) increased the rate of germination and the overall percent germination for all seed lots and dramatically improved germination in the poor germinating seed lots. Preconditioning appears to overcome either a shallow physiological dormancy or compensates for seeds with poor vigor or quality. In either case, seed preconditioning drastically improved seed germination (rate and percent) in greenhouse and field tests for purple coneflower.
Abstract
Scarification and pre-soak treatments with water or 1000 ppm gibberellic acid (GA) accelerated seed germination of Alexandra palm [Archontophoenix alexandrae (F. J. Muell.) H. Wendl. & Drude]. Macarthur palm [Ptychosperma macarthurii (H. Wendl.) Nichols] germination was accelerated following scarification or pre-soaking in 1000 ppm GA, however, in both species greatest acceleration was obtained when the scarification and GA treatments were combined. Germination time of Macarthur palm was also reduced by 6 weeks when sown in beds heated to 27° ± 1°C.
Abstract
Irregular germination and delayed emergence of blueberry, strawberry, blackberry and raspberry seedlings have been noted by various investigators. Seed treatments such as afterripening (1) and acid scarification of strawberry seed (2) improved rapidity of germination, but neither treatment fully overcame the delay in seed germination. In a study with blueberry seed, after-ripening did not improve germination (2). Sporadic germination and delayed emergence of seedlings complicates a breeding program when uniform size of seedlings is desired.
Abstract
Activated carbon stimulated seed germination of lettuce (Lactuca sativa L.) in soil and vermiculite. Stimulation was strongly dependent upon the moisture potential. Germinating seeds were shown to excrete an inhibitor into the micro-environment which cannot diffuse away rapidly at moisture potentials near the soil field capacity or at analogous potentials in vermiculite. Increasing the moisture potential or adding activated carbon caused rapid removal of inhibitor from the seed micro-environment.
Abstract
A light requirement for improved seed germination of lowbush blueberry (Vaccinium angustifolium Ait.) was partially overcome by GA treatments; GA at 500, 1000, 2000, and 4000 ppm stimulated early germination of seeds kept in the dark. The germination rate of seeds exposed to an 8 hour light period was also enhanced by GA treatments. Continuous exposure to concentrations above 1000 ppm resulted in abnormally curled seedlings with necrotic root tips.