Field studies were conducted in consecutive years to evaluate the influence of seeding month and seed soaking on buffalograss [Buchloë ductyloides (Nutt.) Engelm.] establishment, as measured by percentage of coverage and seedling emergence. In 1991, plots where `Sharp's Improved' buffalograss burrs were seeded in May, June, or July exhibited complete coverage 7 weeks after seeding (WAS). Between Apr. and Sept. 1992, mean high and low temperatures were ≈ 3C cooler than in 1991, and seeding in June or July resulted in >95% coverage 9 WAS. In the same year, seeding in April or May required 12 to 13 weeks for complete coverage. Buffalograss seeded in August exhibited <25% coverage by the end of the first growing season. Soaking buffalograss burrs in water before seeding resulted in the emergence of >30% more seedlings 2 WAS compared with nonsoaked burrs and increased coverage by up to 18% on selected rating dates 3 to 13 WAS. However, complete coverage occurred only ≈ week sooner where soaked vs. nonsoaked burrs were planted.
Jack Fry, Ward Upham, and Larry Leuthold
Stanislav Magnitskiy*, Claudio Pasian, and Mark Bennett
Regulation of excessive vegetative growth is of importance in both field and bedding plant production. The goal of the study was to evaluate the effect of preplant seed soaking in growth regulators on the growth control of floricultural (verbena, salvia, pansy, marigold, celosia) and agronomic (cucumber, dill) crops. Seeds were soaked in water solutions of growth regulators of different concentrations ranging according to the crop from 50 to 1000 mg·L-1 for paclobutrazol, 1 to 10 mg·L-1 for uniconazole, 10 to 200 mg·L-1 for ancymidol, 100 to 5000 mg·L-1 for chlormequate chloride and dried at 20 °C for 24 h prior to sowing into plugs. In the first experiment, seeds of verbena, salvia, pansy, and dill soaked for 5 minutes in 50 mg·L-1 paclobutrazol solutions produced seedlings that were up to 43, 18, 30, and 22% shorter than the controls, respectively. Increased paclobutrazol concentrations and soaking time generally corresponded to a greater reduction of plant height, as well as delays and reduction in seedling emergence of all crops, except cucumber. In the second experiment, growth of marigold plugs from seeds soaked in 5 mg·L-1 uniconazole or 60 mg·L-1 ancymidol solutions during 45 min was associated with 23% or 6% plant height reduction, respectively. Soaking of marigold seeds in the solutions of chlormequate chloride did not significantly affect seedling growth. Increasing time of seed soaking in growth regulator solutions did not influence emergence of marigold seedlings. The height of celosia seedlings was only slightly reduced by soaking seeds in the solutions of all studied growth regulators. Results indicate that seed treatments with growth regulators might be useful in growth control of selected bedding plants.
Glen Murray, Jerry B. Swensen, and John J. Gallian
Seedling emergence from primed and nonprimed sugar beet seed (Beta vulgaris L.) was studied for 3 years under field conditions near Kimberly, Idaho, and compared with germination or emergence under controlled laboratory conditions. Maximum seedling emergence did not vary with seed treatment in spite of low field soil temperatures. Time to 50% of maximum emergence was significantly less for seed primed with polyethylene glycol 8000 than for nonprimed seed in only 1 of 3 years. Seed soaked in 30C water for 24 h performed similarly to nontreated seed in the field, but their maximum emergence was significantly improved compared with primed seed in one of two laboratory experiments. Time to 50% of maximum germination was improved by priming with or without a warm water soak in one of the two laboratory experiments.
Stanislav V. Magnitskiy, Claudio C. Pasian, Mark A. Bennett, and James D. Metzger
Shoot stretching in plug production reduces quality and makes mechanized transplanting difficult. The objectives of this study were to measure seedling emergence and shoot height of plugs as affected by paclobutrazol application during seed soaking, priming, or coating on seedling emergence and height. Verbena (Verbena ×hybrida Voss. `Quartz White'), pansy (Viola wittrockiana L. `Bingo Yellow Blotch'), and celosia (Celosia cristata L. `New Look') seeds were soaked in water solutions of paclobutrazol and subsequently dried on filter paper at 20 °C for 24 h. Soaking seeds in paclobutrazol solutions before sowing reduced growth and percentage seedling emergence of verbena and pansy but had little effect on those of celosia. Verbena seeds soaked in 50, 200, or 500 mg paclobutrazol/L for 5, 45, or 180 min produced fewer and shorter seedlings than controls. Osmopriming verbena seeds with 10 to 500 mg paclobutrazol/L reduced seedling emergence. Seedling height and emergence percentage of pansy decreased with increasing paclobutrazol concentrations from 2 to 30 mg·L–1 and with soaking time from 1 to 5 min. The elongation of celosia seedlings was reduced by soaking seeds in 10, 50, 200, or 500 mg paclobutrazol/L solutions for 5, 180, or 360 min. However, these reductions were negligible and without any practical application.
Norman Q. Arancon, Archana Pant, Theodore Radovich, Nguyen V. Hue, Jesse K. Potter, and Chad E. Converse
, 2004 ; Kucera et al., 2005 ). Moisture content of seed or growth media is one of the important external factors affecting seed germination. Seed soaking can soften a hard seedcoat and also leach out any chemical inhibitors in the seed, which may
Lucette Laflamme, Nicolas Tremblay, and Marie-Hélène Michaud
Angelica is grown in Quebec (Canada) for its root-bound medicinal properties. Matol Botanique Int., a major user of Angelica extracts, decided 4 years ago to promote local production in order to secure supplies and quality. However, the crop has to be started from seed that show low and variable germination behavior. Emergence occurs after ± 12 days and most of the germination if obtained after 20 to 40 days depending on seed origin and test conditions. Maximum germination ranges from 6 to 57%. Three treatments were first compared in order to stimulate germination: seed soaking in warm water for 24 h, watering germination trays with algae extracts and placing floating row covers over the trays. Angelica germination was significantly improved only by row covers with a maximum of 24% vs 19%. Results were obtained from experiments with other techniques (stratification, seed conditioning, etc,...) to further improve germination.
2Working for the Horticultural Research Centre, Laval University, Que.
Eric H.C. Chilembwe, William S. Castle, and Daniel J. Cantliffe
Commercially processed citrus seeds of Carrizo citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L) Raf.], Swingle citrumelo (C. paradisi Macf. × P. trifoliata), Cleopatra mandarin (C. reticulate Blanco), and sour orange (C. aurantium L.) were used to test the effects of grading, hydrating, and priming on the rate of germination and seedling emergence. Sorting seed into groups by fresh weight or diameter did not generally improve seed performance. Seed fresh weight was highly correlated with maximum seed diameter; also, large seed weight and size were associated with a larger number of embryos. When seedlings from the extra embryos were removed, large seed produced the largest seedlings. Soaking seeds in aerated water significantly increased germination and emergence rates over unsoaked seeds. Soaking at 35C rather than 25C enhanced these differences. Priming seeds in one of three solutions of polyethylene glycol 6000 (—0.6 to—1.2 Mpa) was not successful> as germination and emergence Per centages were lower than in distilled water.
Katherine Kreuser, William C. Kreuser, Gautam Sarath, and Keenan L. Amundsen
Buffalograss is a warm-season, dioecious grass species yielding burs, which are routinely used for field plantings. The pistillate plants bear the burs containing 1–5 caryopses. Isolated caryopses readily germinate, but caryopses contained within burs exhibit strong dormancy, suggesting that burs inhibit germination. Priming burs with low concentrations of potassium nitrate (KNO3) is used as an industry standard to improve germination. Seed dormancy and germination in many species are strongly influenced by endogenous hormone levels, principally abscisic acid (ABA) and gibberellic acid (GA). It follows that buffalograss seed dormancy might be induced or overcome by altering the ratio of ABA to GA. The objectives of this research were 1) to contrast the effects of priming with KNO3 or water on bur germination, 2) to study how these treatments affected hormone profiles, specifically the ABA/GA ratios in the burs, and 3) to quantify treatment effects on the water permeability of the burs. Hormone profiles were analyzed following four postharvest seed-soaking treatments (24-hour 0.05 m KNO3, 24-hour H2O, 48-hour 0.05 m KNO3, and 48-hour H2O). Water infiltration tests on nontreated, 24-hour H2O-treated, and 24-hour 0.05 m KNO3-treated seeds were also conducted. Inconclusive hormone profiling results did not support the hypothesis that KNO3 postharvest treatment raises GA levels to encourage germination. Instead, our data support changes in seed morphology following KNO3 postharvest seed treatments which alter water permeability of the seedcoat leading to increased germination.
Frank Balestri and William R. Graves
, G.A. Witmer, M.C. 1998 Influence of seed processing by frugivorous birds on germination success of three North American shrubs Amer. Midl. Nat. 140 129 139 Norton, C.R. 1980 Deleterious metabolic and morphological changes resulting from seed soaking
Luqi Li, Matthew D. Sousek, Keenan L. Amundsen, and Zachary J. Reicher
. Leuthold, L. 1993 Seeding month and seed soaking affect buffalograss establishment HortScience 28 902 903 Gaitan-Gaitan, F. 1995 Establishment and stress tolerance of buffalograss. Dissertation, Texas Tech University, Lubbock, TX Gaitan-Gaitan, F. McKenney