Germination Of Oat Research Articles

Phosphorus-containing Compounds at Comparable Germination Stages of Caryopses of Avena Species

A number of the phosphorus transformations accompanying imbibition and initial germination in caryopses of wild oats (A vena fatua L.) differ in nature and kind from those accompanying seedling development. Even in non-dormant lines of wild oat germination is extended and seedling development uneven. The significance of early phosphorus transformations can be obscured. Procedures to synchronize germination stages were developed by (i) using seeds which had been exposed to room temperature for extended periods of dry storage, (ii) inducing germination of imbibed seeds by dehulling, piercing and/or gibberellin A3 treatments, or (iii) constructing artificial seed groupings of known germination percentage by appropriate selection of seeds from an unevenly germinating seed source. All three procedures were effective in identifying those processes associated with initial germination. The best synchronization was obtained with method (i). Germination, in contrast to imbibition, was signalled by a significant drop in inorganic phosphate levels, followed by a later rise as seed reserves of phytate were mobilized for seedling development. Differences in the rates of mobilization of acid-soluble phosphorus compounds were apparent between cultivated oats and genetically non-dormant wild oats.

CHEMICAL CONSTITUENTS IN WILD OAT (Avenu fatua) HULLS AND THEIR EFFECTS ON SEED GERMINATION

Aqueous extracts of dormant wild oat (Avena fatua L.) hulls had a weak inhibitory effect on lettuce seed germination. Both paper and thin layer chromatographic analyses of the ether-soluble acidic fraction showed the presence of phenolics and short-chain fatty acids. No abscisic acid was detected. Vanillin, protochatechualdehyde, p-coumaric acid, ferulic acid and caffeic acid were isolated from hull extracts. Vanillin was shown to be the main water-soluble phenolic inhibitor of lettuce seed germination. At a concentration higher than 6.6 × 10−3M, vanillin was found to be more inhibitory than nonanoic acid to both lettuce and wild oat germination. The concentration of phenolics in the hulls does not account for suppression of wild oat seed germination.

Coating Sodium Azide Granules to Enhance Seed Germination

Research was conducted on the leachability and dissipation of sodium azide applied to soil as a solution or as granules with various coatings. The sodium azide leached readily from all formulations, leaving sections of the soil profile with insufficient concentrations to stimulate germination of dormant wild oat (Avena fatuaL.) seed. Sodium azide-impregnated clay granules coated with 5% (w/w) polyethylene glycol increased germination of wild oat seed two-fold over uncoated granules at a rate of 5.6 kg sodium azide/ha in field experiments. The polyethylene glycol coating reduced the rate of sodium azide dissipation from the soil in growth chamber experiments. Formulation of sodium azide has potential for increasing wild oat germination stimulation under field conditions.

Effects of Metolachlor on Germination, Growth, Leucine Uptake, and Protein Synthesis

The effect of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] on the germination and growth of 14 plant species was investigated. A 10-3M concentration of the herbicide did not reduce germination as much as 10% for corn (Zea maysL. ‘Pioneer 3369A’), English pea (Pisum sativumL. ‘Thomas Laxton’), sicklepod (Cassia obtusifoliaL.), or wheat (Triticum aestivumL. ‘Coker 68–15′) but reduced germination of oat (Avena sativaL. ‘Coker 227′) to 0, lettuce (Lactuca sativaL. ‘Grand Rapids’) to 11%, and peanut (Arachis hypogaeaL. ‘Florunner’) to 14%. A 10-6M concentration did not affect the germination of any species tested. A 10-5M concentration did not significantly decrease length or fresh weight of corn, morningglory, or wheat roots but had at least some adverse effect on all other species tested. At this concentration root length was less than 2/3 of the control for English pea, cucumber (Cucumis sativusL. ‘Ashley’), radish (Raphanus sativusL. ‘Scarlet Globe’), sicklepod, and soybean [Glycine max(L.) Merr. ‘Ransom’]. Metolachlor was supplied to germinating seeds of barley (Hordeum vulgareL. ‘Barsoy’), English pea, and corn either only in the shoot, seed, or root zone, or to all parts. One kg/ha applied in the shoot zone of barley and corn significantly reduced seedling height and dry weight but had no effect when applied in either the seed or root zone. Application in all zones was approximately twice as detrimental as when applied in only the shoot zone. Application of 4 kg/ha in only the shoot, seed, or root zones of English pea did not decrease seedling height or dry weight but application in all zones decreased these values about 98%. A 10-5M concentration of metolachlor decreased leucine uptake by cucumber root tips but not its incorporation into protein. A 10-4M concentration strongly reduced leucine uptake and slightly decreased leucine incorporation into protein.

Observations on the Scutellum. II. Histochemistry and Autofluorescence of the Cell Wall in Mature Grain and During Germination of Wheat, Barley, Oats and Ryegrass

Histochemical studies and fluorescence microscopy of the scutella of wheat, barley, oats and ryegrass indicate that the cell walls of these grasses are basically similar in composition. They are all periodic acid-Schiff's positive, presumably owing to large amounts of hemicelluloses such as xylans. All scutellar cell walls stain with protein stains at all stages of germination, with the exception of the epithelial cell walls of oats which do not stain. Scutellar cell walls stain metachromatically red to purple (hydrated sections) or green (dehydrated sections) when stained with toluidine blue 0. The red to purple colour is indicative of free carboxyl groups, usually owing to the presence of pectin. However, this is not confirmed in this case since two pectin stains fail to react. The green coloration with toluidine blue staining is indicative of phenolic compounds (lignin). This conclusion is supported by the autofluorescence shown by the scutella of all genera. The autofluorescence of oats and rye- grass is initially low, especially at the apex, but increases as germination progresses. Wheat and barley lose fluorescence intensity 3 days after germination but later regain it.

Superoxide Dismutases

Superoxide dismutase was purified from pea (Pisum sativum L., cv. Wando) seeds and corn (Zea mays L., cv. Michigan 500) seedlings. The purified pea enzyme eluting as a single peak from gel exclusion chromatography columns contained the three electrophoretically distinct bands of superoxide dismutase characterizing the crude extract. The purified corn enzyme eluted as the same peak as the pea enzyme, and contained five of the seven active bands found in the crude extract. The similar molecular weights and the cyanide sensitivities of these bands indicated that they are probably isozymes of a cupro-zinc superoxide dismutase. One of the remaining corn bands was shown to be a peroxidase.Superoxide dismutase accounted for 1.6 to 2.4% of the water-soluble protein in seedlings of corn, peas, and oats (Avena sativa L., cv. Au Sable). The superoxide dismutase activity per plant and per milligram water-soluble protein considerably increased during germination of oats and during greening and hook opening of peas.

Effects of Germination of Wheat, Oats, and Pearl Millet on Alpha‐Amylase Activity and Starch Degradation

AbstractHard red winter wheat, oats, and pearl millet were germinated at 15°C for periods up to 14 days. Endosperm areas in kernels fractured with a razor blade and starches isolated from the malted flours were examined with a scanning electron microscope to determine the morphology of starch granules and the nature of α‐amylolytic attack on granules. Free sugars content, damaged starch content, and α‐amylase activity of the flours were determined to establish relationships between physical changes in the cereal grains and formation of α‐amylase during germination.Starch granules in the three cereals were degraded during germination by α‐amylase accompanied by production of free sugars and increases in the damaged starch of flours milled from the germinated grains. The cementing material embedding starch granules in endosperms of wheat and oats decreased and disappeared during germination; these changes were not obvious in germinated millet endosperm. Amorphous‐appearing material seemed to cover starch granules in the endosperm of wheat and oats during later stages of germination, but were not observed in the isolated starch granules.Although wheat starch granules had the highest α‐amylase activity, this enzymic degradation was less than expected. Enzymic attack was evidenced as channels or pits on the surfaces of wheat and millet starch granules. Compound oat starch granules were relatively resistant to enzymic attack and no evidence of erosion of the granule surface was observed; small granula were released from the compound granules during germination. The most extensive degradation was obtained with millet starch, appearing as discrete holes leading to the interior of the granule. Concentric shells were visible in the interior of wheat and millet starch granules, but were not observed in oat starch granules.

The occurrence and function of short chain length fatty acids in plants

The fatty acids with chain lengths from C 5 to C 11 were tested for their physiological activity in seed germination. At a concentration of approx. 2·10 −3 M nonanoic acid could reduce the germination of non-dormant oats (wild and cultivated) by 50%. The other acids were less effective. Lettuce seed germination at a lower concentration, approx. 5·10 −4 M was also inhibited but in this case the inhibition was akin to dormancy in that it could be overcome by treatment with red light or applications of cytokinin or gibberellin (GA). These fatty acids were found to be present in plants and since they have chromatographic behaviours similar to inhibitor-ß it might be that this complex contains them and they contribute to the properties of this inhibitor. The levels of the acids varied according to the organ from which they were extracted, there being high levels in naturally dormant structures and about 100 times less in actively growing material. It is speculated that the acids may be associated with membranes.

The Mode of Action of Pronamide

Pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl)benzamide] inhibited root and shoot growth, but had little effect on the germination of oat (Avena sativaL.) or cucumber (Cucumis sativusL.), and sprouting of quackgrass [Agropyron repens(L.) Beauv.] buds. Root growth was more sensitive than shoot growth. Pronamide decreased the longitudinal growth rate and caused radial enlargement in the elongation region of the roots of oat seedlings within 4 hr. Dry weights of the swollen root tips increased 6% over the controls after 4 hr. Pronamide stopped the growth of established oat plants within 24 hr when added to nutrient culture medium. It caused a slight increase in86Rb uptake by excised oat roots. Pronamide stopped normal mitosis in treated oat roots within 0.5 hr. Examination of treated root tips under a microscope showed numerous cells in arrested metaphase, c-pairs, multinucleate cells, polyploidy and swollen and misshapen nuclei. Incorporation of14C-glucose into oat root cell walls and14C-leucine into protein were increased by 26 and 20% respectively, following 4-hr incubations in pronamide. The primary mode of action of pronamide is mitotic poisoning.

Control of Volunteer Oat in Alfalfa1

AbstractSimazine, atrazine and terbacil were applied to alfalfa (Medicago sativa L.) stands, established with oat (Avena sativa L.) as a companion crop, after the oat was harvested at maturity. Herbicides were applied before the germination of volunteer oat or after both oat and alfalfa had made substantial growth. Excellent control of volunteer oat, without significant alfalfa injury, was obtained with all three herbicides. Control generally was better if the herbicides were applied in September rather than in August. Root carbohydrate reserves of alfalfa may have provided some physiological protection against herbicide injury.

Germination, Growth, and Ecology of Sicklepod

Germination, growth, and potential phytotoxicity of sicklepod (Cassia obtusifolia L.) were studied. Seed germination occurred in the temperature range from 18 to 36 C, but rapid seedling growth occurred only between 30 and 36 C. Seed dormancy caused by a waxy coat resulted in only 15% germination in soil over a 12-month period. A 1:15 (g/ml) water extract of sicklepod tops inhibited germination of cotton (Gossypium hirsutum L.) and oat (Avena sativa L.) seed. Incorporation of sicklepod residues in soil reduced germination of cotton seed but increased persistence of sericea (Lespedeza cuneata (Dumont) G. Don.) and crimson clover (Trifolium incarnatum L.) because damping-off was almost eliminated. There was evidence in nutrient cultures that sicklepod released a phytotoxic residue from its roots, reducing growth of cotton but having no effect on soybeans (Glycine max (L.) Merr.). Sicklepod grew well in soils ranging from pH 3.2 to 7.9. Sicklepod response to N, P, and K levels was similar to cotton and higher than that of soybeans.

Effects of a Magnetic Field on the Germination of Apple, Apricot, and Peach Seeds1

Abstract The effects of a magnetic field on biological systems have been studied extensively in recent years. Murphy (1) reported that a magnetic field accelerates seed germination. Boe and Salunkhe (2) suggested that the magnetic field might act upon auxin or enzyme reactions, or influence free radical formation in inducing tomato fruit ripening. Mericle et al. (3) reported that the magnetic field did not affect the rate of germination of barley seeds, but did increase the rate of shoot and root growth. According to Pittman (4), both germination and growth rates of wheat, oat, and barley seeds were enhanced by a magnetic field at certain orientation.

Effects of a Magnetic Field on the Germination of Apple, Apricot, and Peach Seeds1

Abstract The effects of a magnetic field on biological systems have been studied extensively in recent years. Murphy (1) reported that a magnetic field accelerates seed germination. Boe and Salunkhe (2) suggested that the magnetic field might act upon auxin or enzyme reactions, or influence free radical formation in inducing tomato fruit ripening. Mericle et al. (3) reported that the magnetic field did not affect the rate of germination of barley seeds, but did increase the rate of shoot and root growth. According to Pittman (4), both germination and growth rates of wheat, oat, and barley seeds were enhanced by a magnetic field at certain orientation.

Phosphorus Metabolism of Germinating Oat Seeds

An investigation has been made of the changes in the major phosphorus containing substances in Avena sativa during the first 8 days of dark germination. The endosperm, roots, and shoots were analyzed separately for acid soluble-P, phytic acid-P, inorganic-P, lipid-P, nucleic acid-P, and protein-P. Phytic acid-P comprised 53% of the total seed phosphate, while the sum of lipid-P, nucleic acid-P and protein-P comprised 27% of the seed phosphate. All these reserve phosphate materials were mobilized and transferred to the developing axis. The phosphate from phytic acid appeared almost entirely as inorganic-P in the roots and shoots. A close stoichiometry existed between the rate of loss of nucleic acid-P from the endosperm and its rate of appearance in the roots and shoots. Thus no net synthesis of nucleic acid occurred during the 8-day period examined. The rate of synthesis of lipid-P in the roots and shoots exceeded its rate of disappearance from the endosperm during the first 4 days of germination. Protein-P increased in the roots and shoots during germination, but at a rate less than its rate of disappearance from the endosperm. The results provide a relatively complete description of the over-all aspects of phosphorus metabolism associated with germination of oats.

The effect of herbicides, anhydrous ammonia and seed ing rate on winter production of oats sod-sown into grass dominant pasture

A factorial field experiment, comparing three rates of nitrogen as anhydrous ammonia, two seeding rates of oats, and the presence or absence of a herbicide applied to grass pastures before sod-seeding, was conducted at Kyogle, New South Wales in 1964. Plots were sown in mid-autumn and harvested in winter and early spring. Increased applications of nitrogen and the higher seeding rate increased both dry matter yield and total nitrogen content. Application of herbicide significantly increased yield at the low rates of nitrogen but not at the highest rate. Anhydrous ammonia at 120 lb of nitrogen an acre had no effect on the germination of oats seed and provided adequate nitrogen for growth of oats without the need for herbicide application or cultivation of the grass pasture. The results suggest that oats can be successfully sod-seeded into grass dominant pastures by using 120 lb of nitrogen as anhydrous ammonia and four bushels of oats an acre.

Plant Extracts, Residues, and Soil Minerals in Relation to Competition of Quackgrass with Oats and Alfalfa

When crop plants were competing with well-established quackgrass (Agropyron repens) for the same nutrient supply, chlor- osis and stunting of crop plants occurred. Apparently this was due to the greater ability of quackgrass to withdraw available nutrients, especially nitrogen, and to a lesser extent phosphorus and potassium, from the nutrient solution. No evidence was obtained for a phytotoxic substance from living quackgrass roots or rhizomes that could inhibit germination or growth of alfalfa and oats. Quack- grass residues in large amounts caused chlorosis and stunting in alfalfa and oats when added to soil. The evidence obtained linked this behavior to the high C:N ratio with consequent temporary de- ficiency of available nitrogen. Water extracts of quackgrass leaves or rhizomes were not phytotoxic unless subjected to high temperatures during or subsequent to extraction. If soils contained decomposing quackgrass or crop plant residues, extremely phytotoxic extracts of such soils were obtained, but only when soils were saturated and decomposition was anaerobic.

Ramulosin: Inhibitory effect against plant seeds and various fungi

Ramulosin, a new fermentation product reported recently from this laboratory, was tested for biological activity. The compound inhibited germination of wheat and oats at 10 p.p.m.; tomato and grass seeds at 100 p.p.m.; and corn, clover, sorghum and morning glory seeds at 1000 p.p.m. No appreciable activity was noted in tests with Pinto and soy beans. Ramulosin also inhibited the germination of conidiospores of Aspergillus niger and Fusarium moniliforme; ascospores of Chaetomium globosum; and sporangiospores of Rhizopus stolonifer and Mucor rouxii. Although it did not exhibit antibacterial activity, ramulosin did retard the growth of several basidiomycetes and ascomycetes.

Effect of 1,2,4,5‐Tetrachlorobenzene on the Germination and Seedling Vigor of Barley, Oats, and Wheat1

SynopsisThe effects were most detrimental in sandy soil. As the soil type changed from sand, to sandy loam, to clay loam, to clay, the damage decreased. With each increase in the interval between soil treatment and planting there was a general increase in germination and seedling vigor.

Effect of Methyl Bromide and Hydrocyanic Acid Fumigation on the Germination of Oats1

Two varieties of oats, Kanota and Ventura, with a graded moisture range of 8, 10, 12, and 14% were fumigated with methyl bromide in 100-cubic-foot gastight chambers at an exposure period of 72 hours. Various dosages and temperatures were used. One variety of oats, Kanota, was fumigated with methyl bromide and hydrocyanic acid under varying conditions of temperature, exposure, and dosages of fumigant. One half of the fumigated samples of seed received one fumigation; the others were fumigated twice. Two series of germination tests were made, the first within 5 days following fumigation of seeds, and the second after 84 days of postfumigation storage at 50° F. Under the conditions of the experiments, the germination of oats was not affected by fumigation with hydrocyanie acid. Dosage, temperature, period of exposure, and the moisture content of seeds were variables found to be most important in contributing to injury from methyl bromide. Although oat seeds were relatively resistant to fumigation with methyl bromide, some injury did occur.

On the Consumption of the Stored Foods in the Seeds During Germination of Cereals. : 8. Expansion of Epithelium Tissue of Scutellum in Oat Seed.

During the period of germination of oat seed, the scutellum was found to grow up to the top of the grain. This phenomenon is characteristic to oats plant. The epithelium of the scutellum became large in area according to the expansion of the scutellum. Therefore, the absorption of food materials in the grain by the scutellum may possibly be more vigorous in oats than in other cereals.