Germination Of Wild Oat Research Articles

Identification and extraction of herbicidal compounds from metabolites of Trichoderma polysporum HZ-31

AbstractTrichoderma polysporum (Link) Rifai HZ-31 fermentation broth was separated and purified by extraction, column chromatography, and high-performance liquid chromatography. Four monomer compounds with strong herbicidal activity were obtained: p-hydroxyphenyl-2,3-dihydroxypropyl ether, o-hydroxy-3-carbonyl-1-phenylpropanol, 1,8-propanediol o-xylene, and 2-3-dihydroxypropyl propionate. The biological activity verification test indicated that the four monomer compounds could inhibit the germination of wild oat (Avena fatua L.) and canola (Brassica napus L.) seeds. Of the four, compound 3 (1,8-propanediol o-xylene) had obvious inhibitory effects on the germination of A. fatua and B. napus seeds, with inhibition rates of 83.33% and 86.67%, respectively. Therefore, the identification of this monomer compound lays a foundation for the further development of a novel microbial herbicide by directly utilizing it and developing new derivatives with herbicidal functions as lead compounds.

Herbicidal potential of Aerva javanica to control wild oat in wheat crop

We investigated the phytotoxicity of desert cotton (Aerva javanica) extracts on wild oat and wheat. Aqueous extracts from A. javanica roots, leaves and inflorescences collected from Jeddah and Al-Baha regions, Saudi Arabia were used. Generally, the allelopathic potential of water extracts of A. javanica collected from Jeddah were more in inhibitory to wild oat germination and seedlings growth than those from Al-Baha. In both regions, root extracts were inhibitory to wild oat followed by leaves and inflorescences extracts. All test aqueous extracts of both regions did not inhibit the wheat germination or seedlings growth.Whreas, the wild oat germination was reduced by root extracts 58.62 %, 28.62 % leaves extracts : 32.72 %, 17.72 % and inflorescences extract 28.11 %, 12.13 % by in plants samples collected from Jeddah and Al-Baha, respectively. Wild oat radical length was inhibited by root extracts 53.27 %, 32.84 % leaves 42.35 %, 9.63 % and inflorescences extracts 22.64 %, 16.75 % in case of Jeddah and Al-Baha plants, respectively. In pot culture experiment, all treatments markedly reduced the plant dry weight and soluble carbohydrates, proteins and free amino acids contents in wild oat. The differences in the allelopathic potentials of studied A. javanica extracts were related to the qualitative variations in their phytochemicals constituents. Our results showed that A. javanica extracts could be safely used to control wild oat growth in wheat fields after more detsaled research..

We investigated the phytotoxicity of desert cotton (Aerva javanica) extracts on wild oat and wheat. Aqueous extracts from A. javanica roots, leaves and inflorescences collected from Jeddah and Al-Baha regions, Saudi Arabia were used. Generally, the allelopathic potential of water extracts of A. javanica collected from Jeddah were more in inhibitory to wild oat germination and seedlings growth than those

This glasshouse study aimed to determine the herbicidal activity of allelochemicals 2,4-di-tert-butylphenol (2,4-DTBP) on test weeds (Asystasia gangetica, Eleusine indica, Leptochloa chinensis and Oldenlandia verticillata) and to find the tolerance of test crops (Brassica rapa, Oryza sativa, Zea mays) to 2,4-DTBP. The 2,4-DTBP applied at 7 kg ai/ha inhibited the weeds seedling growth by 15-40 % only, showing its poor post emergence herbicidal activity. In contrast, soil bioassay confirmed pre-emergence herbicidal activity of 2,4-DTBP that reduced the seedling growth of weeds (L. chinensis, E. indica and O. verticillata) by 50- 80 % at 2.5 kg ai/ha but A. gangetica was tolerant to 2,4-DTBP even at 5 kg ai/ha. Crop tolerance test revealed that Zea mays was tolerant to 2,4-DTBP. In contrast, root lengths of transplanted Brassica rapa seedlings and Oryza sativa seedlings were reduced by 10- 15 % at 2,4-DTBP doses of 1.25 to 5 kg ai/ha, 14 days after treatment. However, these two crops seedlings became tolerant to 2,4-DTBP at 5 kg ai/ha, when applied 4 days after transplanting. Thus 2,4-DTBP may be developed as novel pre-emergence natural herbicide, without injuring the crops depending on their growth stages and crop species.

Allelopathic Effect of Lotus and Arrowhead Weed on Wheat, Wild Oat and Milkthistle Germination

ABSTRACT: An experiment was conducted to investigate the allelopathic effects of lotus (Nelumbo nucifera Gaertn.) and arrowhead (Sagittaria sagittifolia (Brummitt & Powell): L.) on seed germination of wheat and two associated weeds, namely, wild oat (Avena fatua L.) and milk thistle (Silybum marianum (L.) Gaertn.). The experiment was laid out in a Completely Randomized Design during May, 2014. Dried biomasses of lotus and arrowhead leaves were soaked in distilled water for 48 hrs for extract preparation. The extracts were applied at a rate of 5 and 10% concentrations to the seeds of wheat, wild oat and milk thistle at 25 °C in 10 cm wide Petri plates. A control treatment where only distilled water was applied to the seeds, was included for comparison. Data were recorded on germination (%), shoot length (cm), shoot and root fresh weights (g). The results revealed that 10% lotus extract reduced germination of wild oat (0.00%) and milk thistle (13.3%) but comparatively enhanced that of wheat (20%). By contrast, arrowhead totally inhibited germination of wheat and wild oat as compared to milk thistle (16.66%). Similarly, 10% lotus extract favored shoot length and root weight of wheat and milk thistle, whereas 100% inhibited wild oat. By comparison, arrowhead completely inhibited shoot length and root weight of wheat and wild oat at 10% conc. and enhanced milkthistle (3.00 cm and 3 g). A higher lotus extract conc. affected wild oat more than wheat and milkthistle, while arrowhead weed affected almost all test species. In conclusion, these aquatic weeds can be used as mulch in wheat in nearby fields of the infested aquatic water bodies for wild oat control, weed biomass disposal and nutrient addition to the soil.

Bioherbicidal activity of allelopathic bacteria against weeds associated with wheat and their effects on growth of wheat under axenic conditions

Allelopathic bacteria found to selectively inhibit weeds but not wheat in our earlier study were selected to evaluate their impact on three weeds and wheat under axenic conditions. Inoculated seeds of each species were sown in sand jars for 25 days. Results indicated that the applied strains variably inhibited germination of wild oat, little seed canary grass and broad leaved dock from 15.2 to 63.3, 18.5 to 58.7 and 18.4 to 60.5% and dry matter from 12.4 to 65, 22.8 to 81.4 and 21.7 to 71.3% than their controls, respectively. These effects were also evident in other growth parameters. Growth of wheat was significantly improved by four strains while others caused non-significant effects. Selectivity of these strains was also reflected in differential root colonization ability. These strains were characterized for various microbial and biochemical parameters. These strains may further be evaluated for their bioherbicidal activity under natural conditions.

Control of wild oat ( Avena fatua) using some phenolic compounds I – Germination and some growth parameters

The percentage of germination of wild oat was significantly inhibited by increasing the concentrations of phenolic compounds. Ferulic acid was the most effective compound which completely inhibited germination at a concentration of 3.0 mM. At the same time, wheat and barley were slightly affected with different concentrations of the four phenolic compounds. The percentage of germination of wheat significantly decreased with increasing of ferulic acid reaching a maximum inhibition at 3.0 mM concentration. On the other hand, the germination of wheat was not affected with the other three phenolic compounds. The percentage of germination of barley was not affected with all phenolic compounds except for hydroxy phenolic acetic acid which has significant effect at a concentration of 3.0 mM. Salicylic acid significantly inhibited the growth parameters gradually in wild oat, wheat and barley. The shoot/root ratio was decreased in wild oat and barley, while the ratio increased in wheat. The growth parameters were completely inhibited at 3.0 mM of ferulic acid for both wild oat and wheat but slightly inhibited for barley. The shoot/root ratio was increased in all concentrations of ferulic acid except at 3.0 mM which was completely inhibited for both wild oat and wheat, while the ratio was increased in all treatments of ferulic acid in the case of barley. The growth parameters were highly significant and decreased in wild oat, wheat and barley with increasing the concentrations of hydroxybenzoic acid and hydroxyphenyl acetic acid. The shoot/root ratio was not changed in all concentrations except at 3.0 mM in the case of wild oat, the ratio was decreased at 2.0 and 3.0 mM in the case of wheat, while the ratio increased in most of hydroxybenzoic acid concentrations in the case of barley. The shoot/root ratio was increased with increasing of the hydroxyphenyl acetic acid concentrations.

Field Pea Seed Residue: a Potential Alternative Weed Control Agent

Field pea seed from bin cleaning operations stored overwinter on nearby cropland was observed to correlate with weed and crop growth suppression for up to three subsequent years. To explore the phenomenon more explicitly, plant growth suppression trials were undertaken with soil sampled 18 mo apart from two locations that had contained field pea seed residues. Test plant species grown in the residue-affected and nearby residue-free soils were compared in greenhouse experiments. Germination was either fully inhibited or emergence was delayed by more than one week. Dry matter accumulation of test species grown in residue-affected soil was significantly reduced compared to dry matter of these test species grown in residue-free soil (P < 0.0001). Canola and field pea were inhibited more than wheat and green foxtail over both years. Greenhouse trials also revealed that germination of wild oat was inhibited in the residue-affected soils, although wheat and grassy weeds were less suppressed than dicots overall. Significant reductions of weed species diversity and abundance were correlated to residue-affected soils (P < 0.0001) when compared to residue-free soils using multi-response permutations procedures. Germination of wheat and canola seed was inhibited, using aqueous extracts of weathered pea seeds or extracts of the residue-affected soil in bioassays in sterile media. An allelopathic response was proposed to explain the above results, indicating a need for further research on this system. Weed management strategies could be developed with field pea seed residues to provide innovative weed control techniques.

Wild Oat (Avena Fatua L.) and Canary Grass (Phalaris Minor Ritz.) Management Through Allelopathy

Wild Oat (Avena FatuaL.) and Canary Grass (Phalaris MinorRitz.) Management Through AllelopathyEnvironmental contamination, herbicide resistance development among weeds and health concerns due to over and misuse of synthetic herbicides has led the researchers to focus on alternative weed management strategies. Allelochemicals extracted from various plant species can act as natural weed inhibitors. In this study, allelopathic extracts from four plant species sorghum [Sorghum bicolor(L.) Moench], mulberry (Morus albaL.), barnyard grass [Echinochloa crusgalli(L.) Beauv.], winter cherry [Withania somnifera(L.)] were tested for their potential to inhibit the most problematic wheat (Triticum aestivumL.) weeds wild oat (Avena fatuaL.) and canary grass (Phalaris minorRitz.). Data regarding time to start germination, time to 50% germination, mean germination time, final germination percentage, germination energy, root and shoot length, number of roots, number of leaves, and seedling fresh and dry weight was recorded for both the weeds, which showed that mulberry was the most inhibitory plant species while sorghum showed least allelopathic suppression against wild oat. Mulberry extracts resulted in a complete inhibition of the wild oat germination. The allelopathic potential for different plants against wild oat was in the order: mulberry > winter cherry > barnyard grass > sorghum. Mulberry, barnyard grass and winter cherry extracts resulted in a complete inhibition of canary grass. Sorghum however exhibited least suppressive or in some cases stimulatory effects on canary grass. Plants revealing strong allelopathic potential can be utilized to derive natural herbicides for weed control.

The Heterotoxicity of Hordeum vulgare L. Extracts in Four Growth Stages on Germination and Seedlings Growth of Avena ludoviciana

Phytotoxicity of barley extracts (Hordeum vulgare L.) on wild oat (Avena ludoviciana Durieu) was investigated. Water extracts five varieties of barley were bioassayed on germination and seedling growth of wild-oat to test the heterotoxicity of barley on wild-oat, study the dynamics of allelopathic potential over four growth stages and identify the most allelopathic plant part of barley in each stage. Whole barley plants were extracted at growth stage 4 (stems not developed enough), whilst for the following growth stages roots, stems, panicles and leaves were extracted separately. Seedling growth bioassays demonstrated that the wild-oat responded differently to the allelopathic potential of barley. For wild-oat radical growth and coleoptile growth were more depressed than germination, though. The allelopathic potential of barley plant parts was not stable over its life cycle for wild-oat. Leaves and stems were the most phytotoxic barley plant parts for wild-oat in the all stages. Among the varieties Eizeh appeared as the best one showing toxicity to seed germination of wild oat at its stage 4 and 8. Results suggested that the response by wild-oat varied depending on the source of allelochemicals (plant part) and the growth stage of the barley plant and kind of variety. The results leaded to conclude that Eizeh variety of barley was good to grow as it has good check on seed germination of wild oat plants as well as it also retarded the growth of root and shoot length of oat.

Bioactivity of the Fungal Metabolite (8R,16R)-(−)-Pyrenophorin on Graminaceous Plants

A secondary metabolite was isolated from cultures of a Drechslera avenae pathotype with host specificity to Avena sterilis and identified as the macrodiolide (8R,16R)-(-)-pyrenophorin (8,16-dimethyl-1,9-dioxa-cyclohexadeca-3,11-diene-2,5,10,13-tetraone). A considerable yield of the substance was obtained after 8-12 days of incubation at temperatures of 15-20 degrees C. The compound at a concentration of 60 microM inhibited seed germination of wild oats (Avena sterilis, A. fatua), oat (A. sativa), wheat (Triticum aestivum), and barley (Hordeum vulgare). Root growth of pregerminated seeds of the graminaceous plants was stimulated, remained unaffected, or was inhibited by pyrenophorin at 10-30, 31-50, and >51 microM, respectively. The metabolite caused abnormal chlorophyll retention in leaf sections of all five graminaceous plants, but seedling cuttings partially immersed in 1000 microM solutions remained unaffected. The rate of chlorophyll dissipation was decreased by half in leaf sections treated with pyrenophorin at 320 microM compared with the control. These findings are discussed and compared with data on the production and bioactivity of the macrodiolide (5S,8R,13S,16R)-(-)-pyrenophorol, which has a similar stereochemical configuration.

Seed germination of common weed species as affected by oxygen concentration, light, and osmotic potential

Laboratory experiments were conducted to determine the effects of oxygen concentration (21, 10, 5, and 2.5%), exposure to light, and osmotic potential on the germination of wheat, canola, and various weed species. Germination of most species increased as osmotic potential was increased. Seed germination for some species like barnyardgrass was inhibited by the combination of exposure to normoxic (21% oxygen) conditions and light. This combination of conditions may function as a signal to prevent soil surface germination. Wild mustard germination increased with increasing oxygen concentration when seeds were not exposed to light, whereas green foxtail germination was relatively insensitive to oxygen concentration. Wild oat germination increased with increasing osmotic potential, and osmotic potential had a greater influence when the seeds were exposed to light. Dandelion, foxtail barley, curly dock, and perennial sowthistle germination was affected more by osmotic potential and light exposure than by oxygen concentration. A better understanding of the mechanisms of depth detection for specific species will lead to a better understanding of their recruitment biology. This information may help model the potential for invasion and proliferation of each species as well as devise improved management strategies.

Effects of prolonged light on germination of six lines of wild oat (Avena fatua)

Effects of prolonged light irradiation on seed germination of wild oat (Avena fatua L.) were studied in three nondormant and three dormant genetic lines. Light responses were observed in each of the lines tested. The expression of the light reaction is related to the genetic variability and dormancy states of the seeds. The light reaction can be observed in the dormant lines by removing the dormancy blocks in the seeds either through afterripening or by treatment with gibberellic acid or azide. Prolonged far-red, blue, and white light are inhibitory to germination. Prolonged red light had neutral, or inhibitory, effects compared with the corresponding dark germination. Germination responses to light depend on both the condition of phyto-chrome established by the light environment and the state of dormancy in wild oat seeds. Key words: phytochrome, dormancy, afterripening, genotype, gibberellin, azide.

Germination stimulation in wild oats (Avena fatua L.) by synthetic strigol analogs and gibberellic acid

At concentrations of 0.01–1 mM, five synthetic multiring analogs of strigol were effective germination stimulants of intact and dehulled wild oat (Avena fatua L.) seeds. The effect was concentration-dependent and equaled or exceeded that produced by equimolar gibberellic acid (GA3). The most effective strigol analog treatments induced 55–80% germination within 7 days in intact wild oat seeds and resulted in 63–86% germination and normal seedling growth over 14 days. Intact wild oat controls germinated 14% after 14 days. The stimulation of wild oat germination by these synthetic strigol analogs demonstrates that these compounds, initially developed as germination stimulants for the seeds of the parasitic weed, witchweed (Striga asiatica L. Kuntz.), have bioregulatory activity in dormant seeds of monocots, as well as dicots. None of the compounds tested significantly affected the germination of nondormant cultivated oat seeds (Avena sativa L.). The commonly used dispersal agent, Tween 20 (0.1%), was found to inhibit germination of cultivated oats, alone and in the presence of 2% acetone.

Interactions Among Ethephon, Nitrate, and After-Ripening in the Release of Dormancy of Wild Oat (Avena fatua) Seed

Germination of dormant wild oat (Avena fatuaL. # AVEFA) seed was examined in response to various concentrations of ethephon (2-chloroethylphosphonic acid), KNO3, or both together in the dark at temperatures ranging from 7 to 32 C. Both chemicals significantly (P = 0.05) promoted germination and their effects were additive. Maximum stimulation of germination in response to all treatments occurred at 7 C, with a gradual decrease in reponse as temperature or duration of after-ripening, the seed that retained dormancy during storage remained responsive to ethephon also occurred during storage of mature seed at 3 to 32 C. The rate and extent of this dormancy loss increased with an increase in storage temperature. Regardless of the temperature or duration of after-ripening, the seed that retained dormancy during storage remained responsive to ethephon and KNO3treatments. Suitable combinations of after-ripening, ethephon, and KNO3induced over 90% germination of seed that was dormant at maturity. Experimental evidence has been obtained that suggests that this percentage may represent the total number of viable seed in the population. While ethephon promoted seed germination, it severely stunted root and shoot growth of the resulting seedlings. It appears that strategies could be developed to combine the use of ethephon and nitrate with the natural process of after-ripening to enhance and synchronize wild oat germination.

Radial elongation of the epidermal cells of scutellum during caryopsis germination of wild oats (Avena fatua)

The radial elongation of epidermal cells of the scutellum of wild oat (Avena fatua L.) embryos was studied quantitatively. In the nondormant embryos, the length of these cells, both on the adaxial and abaxial sides of the scutellum, was doubled in 10 days after the beginning of the imbibition of caryopses in water; no such elongation of cells was observed in the dormant embryos. The epidermal cells elongated to form papillae only after the primary root had emerged from the caryopsis. The length of the entire scutellum and that of its epidermal cells increased significantly in the presence of gibberellic acid and glucose or sucrose. It is suggested that the epidermal cell elongation is a postgermination phenomenon involving absorption and transport of the products of starchy endosperm hydrolysis, thus promoting further growth in the germinated embryo of the wild oat.

The Effect of Temperature during Parental Vegetative Growth on Seed Germination of Wild Oats (Avena fatua L.)

The Effect of Temperature during Parental Vegetative Growth on Seed Germination of Wild Oats (Avena fatua L.)

Actions of sodium hypochlorite and hydrogen peroxide on seed dormancy and germination of wild oats, Avena fatua L.

SummarySodium hypochlorite (NaOCl) can release dormancy of imbibed wild oat (Avena fatua L.) seeds. Treatments found effective included (i) immersing intact seeds in 800 mm NaOCl for 1 h followed by incubation on 5 × 10−4m gibberellin A3(GA3); (ii) immersing dehulled seeds in 800 mm NaOCl for 1 min followed by incubation on 5 × 10−4m GA3; (iii) immersion of dehulled seeds in much lower concentrations of NaOCl, e.g. 13 4 mm for 3 h followed by incubation on water; or (iv) incubating dehulled seeds on a low concentration of NaOCl. Based on the concentrations of each of the reagents required to produce equivalent responses, NaOCl is approximately 4–6 times more effective than hydrogen peroxide (H2O2) in triggering the onset of germination, and 6 times as effective in causing growth inhibition in the roots. These results suggest the modes of action of NaOCl and H2O2 in the termination of dormancy reside in a modification of the properties of the hull and seed coat membranes, and in the provision of additional oxygen to the seed.

Wild Oat (Avena fatua) Seed Environment and Germination

Experiments were conducted in the field and laboratory from 1978 to 1981 to determine the effect of crop residues, manure, and inorganic nitrogen on wild oat (Avena fatua L. ♯3 AVEFA) seed (seed as used here represents an intact floret) dormancy. Turkey manure usually stimulated wild oat seed germination more than crop residue, cow manure, or inorganic nitrogen. Seed germination of different wild oat accessions varied in response to turkey manure. Germination of dormant seed in water was stimulated after 8 weeks or after overwintering in the presence of turkey manure in the field and after 10 days in the presence of turkey manure in petri dishes in the laboratory. Turkey manure caused growth of wild oat shoots in petri dishes, but usually roots were absent. A nonmicrobial, water-soluble component of turkey manure was responsible for stimulating wild oat seed germination. Turkey manure treatment of dormant wild oat seed increased the percentage of seed that would not germinate in gibberellic acid. Germination of nondormant wild oat seed of Accession 77 was reduced, but Accession 64 was unaffected by turkey manure. Germination of wild oat was low when the seeds overwintered on the soil surface, regardless of seed age or length of overwintering.

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.

EFFECT OF FALL AND SPRING TILLAGE ON WILD OAT GERMINATION

In field experiments repeated over a 3-yr period fall tillage was superior to spring tillage for stimulating germination of wild oat (Avena fatua L.). A cultivator was the most effective implement for stimulating seed germination. A double disc was less effective than a cultivator; harrows were relatively ineffective.Key words: Tillage, wild oat, germination, fall, spring