Germination response to phytochrome depends on specific dormancy states in wild oat (Avena fatua)

1993 ◽  
Vol 71 (11) ◽  
pp. 1528-1532 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson
Keyword(s):  
Relative Humidity ◽  
Gibberellic Acid ◽  
Red Light ◽  
Avena Fatua ◽  
Mechanical Injury ◽  
Wild Oat ◽  
Dormancy Breaking ◽  
Negative Effects ◽  
Germination Response ◽  
Genetic Origins

Effects of brief red and far-red light on germination of seeds from dormant lines of wild oat (Avena fatua L.) were studied in combination with mechanical injury to the seed coat, application of gibberellin A3, or changes in relative humidity during afterripening. Aberrant germination responses to phytochrome action were observed in the mechanically injured seeds in some of the lines, i.e., brief red light inhibited or delayed germination induced by injury, and immediately following far-red light cancelled the negative effects. Phytochrome action influenced germination of the gibberellin-treated seeds in a normal fashion, although effects of the gibberellic acid and brief red light on germination were not additive. Brief red light inhibited germination of seeds afterripened in zero relative humidity; the same light promoted germination of those in 30 and 60% relative humidity. Germination response to phytochrome in wild oat depends on specific seed dormancy states, illustrated by genetic origins, dormancy-breaking methods and afterripening conditions. Key words: Avena fatua, dormancy, mechanical injury, gibberellin A3, phytochrome, relative humidity.

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

1991 ◽  
Vol 69 (7) ◽  
pp. 1414-1417 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson
Keyword(s):  
Seed Germination ◽  
Genetic Variability ◽  
Gibberellic Acid ◽  
Red Light ◽  
Avena Fatua ◽  
Wild Oat ◽  
Inhibitory Effects ◽  
Light Responses ◽  
Light Reaction ◽  
Oat Seeds

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.

Carbohydrate concentrations and interactions in afterripening-responsive dormantAvena fatuacaryopses induced to germinate by gibberellic acid

1993 ◽  
Vol 3 (4) ◽  
pp. 271-278 ◽  
Author(s):  
M. E. Foley ◽  
M. B. Nichols ◽  
S. P. Myers
Keyword(s):  
Gibberellic Acid ◽  
Avena Fatua ◽  
Wild Oat ◽  
Sugar Production ◽  
Carbohydrate Utilization ◽  
Per Se ◽  
Induced Changes ◽  
Over Time ◽  
Excised Embryos

AbstractIt has been proposed that gibberellic acid (GA3) promotes germination by overcoming restrictions in sugar production and utilization in afterripening-responsive dormant caryopses. While their germination rates were similar, germination commenced sooner in afterripened wild oat (Avena fatuaL.) caryopses than in dormant caryopses treated with GA3and dormant excised embryos treated with GA3plus fructose (Fru). Limited germination occurred in dormant excised embryos cultured with GA3alone. Carbohydrate concentrations were measured over time in dormant caryopses and excised embryos whose germination was induced with GA3and GA3plus Fru. The concentration of sucrose (Suc) in the endosperm declined prior to germination of dormant GA3-treated caryopses. Raffinose (Raf) family oligosaccharides in the embryos of dormant GA-treated caryopses remained relatively constant prior to and shortly after the onset of germination. In contrast, Raf family oligosaccharides in the embryos of afterripened caryopses declined prior to germination. Together this suggests Raf family oligosaccharide utilization is not associated with germinationper se.Increased starch levels, which occurred in dormant excised embryos treated with Fru and GA3plus Fru, were associated with dormancy because similar effects were not apparent in afterripened embryos cultured with Fru. An initial decline in the concentration of Raf family oligosaccharides in dormant embryos cultured with GA3or GA3plus Fru seems to be a result of the excision process. GA3appears to stimulate the germination of dormant embryos by enhancing the uptake or utilization of Fru. It appears that GA3and afterripening-induced changes in carbohydrate utilization in dormant caryopses are different.

Studies of acid-soluble phosphorus compounds in genetically pure lines of Avena fatua with different dormancy characteristics

1982 ◽  
Vol 60 (10) ◽  
pp. 2099-2104 ◽  
Author(s):  
J. C. Jain ◽  
W. A. Quick ◽  
A. I. Hsiao
Keyword(s):  
Inverse Correlation ◽  
Avena Fatua ◽  
Significant Decline ◽  
Phosphorus Compounds ◽  
Relative Depth ◽  
Uniform Field ◽  
Wild Oat ◽  
Dormancy Breaking ◽  
Soluble Phosphorus ◽  
Pure Lines

Seven genetically pure lines of wild oat selections of known dormancy characteristics were grown under uniform field conditions. Acid-soluble phosphorus components were determined in the dry seeds, in the imbibed seeds, and in imbibed seeds with dormancy-breaking treatments. No significant correlation between dormancy level and acid-soluble phosphorus composition was established for any component other than inorganic phosphorus (Pi). In dry caryopses Pi varied from 5 to 10% of the acid-soluble fraction. A highly significant inverse correlation was found between levels of Pi in the dry caryopsis and the relative depth of dormancy of the wild oat selection considered. The effect of imbibition on Pi level varied with depth of dormancy. Intact seeds of nondormant lines imbibed for 52 h showed a significant decline in Pi prior to coleorhiza protrusion from the dehulled caryopsis. More deeply dormant lines of Avena fatua (pure lines Anderson 51, Anderson 474, or Crop Science 40) required up to 10 days of incubation for significant drops in Pi to appear, while the most dormant lines (pure line Montana 73 and Idaho) did not evidence significant decline in Pi even after 10 days of incubation. The increase in Pi level associated with coleorhiza protrusion could be produced in the imbibed dormant lines by piercing them with a fine needle, by treating with gibberellic acid (GA3), or by a combination of the two treatments. The combination of piercing and GA3 treatment was much more effective than either treatment alone.

Promotion of Germination of Dormant Weed Seeds by Substituted Phthalimides and Gibberellic Acid

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 285-289 ◽  
Author(s):  
James D. Metzger
Keyword(s):  
Gibberellic Acid ◽  
Avena Fatua ◽  
Weight Basis ◽  
The Other ◽  
Wild Oat ◽  
Rumex Crispus ◽  
Wild Mustard ◽  
Field Pennycress ◽  
Weed Seeds ◽  
Brassica Kaber

Both gibberellic acid and the substituted phthalimide AC-94377 [1-(3-chlorophthalimido)cyclohexanecarboximide] actively promoted germination of dormant seeds in five species out of nine. The species that responded to both compounds included wild oat (Avena fatuaL.), wild mustard [Brassica kaber(DC.) L.C. Wheeler], curly dock (Rumex crispusL.), field pennycress (Thlapsi arvenseL.) and tansy phacelia (Phacelia tanacetifoliaL. Benth.). on a weight-per-weight basis, the ability of AC-94377 to stimulate germination was equal to, or greater than, GA3. The other two substituted phthalimides tested, AC-92803 [2-(3-chlorophthalimido)-2-methyl-2-isobutyl-acetamide] and AC-99524 [1-tetrahydrophthalimido-cyclohexane-carboximide], had either slight or no stimulatory activity.

Corrigendum to: Improved germination of the Australian natives: Hibbertia commutata, Hibbertia amplexicaulis (Dilleniaceae), Chamaescilla corymbosa (Liliaceae), and Leucopogon nutans (Epacridaceae)

2004 ◽  
Vol 52 (4) ◽  
pp. 559
Author(s):  
Sally M. Allan ◽  
Steve W. Adkins ◽  
Christine A. Preston ◽  
Sean M. Bellairs
Keyword(s):  
Gibberellic Acid ◽  
Acid Solution ◽  
Seed Coat ◽  
Shock Treatment ◽  
Dormancy Breaking ◽  
Australian Species ◽  
Germination Response ◽  
Embryo Dormancy ◽  
Site Rehabilitation ◽  
Smoke Water

Hibbertia commutata Steudel, H. amplexicaulis Steudel, Chamaescilla corymbosa (R.Br.) F.Muell. Ex Benth. and Leucopogon nutans E.Pritzel are four Australian species that are difficult to germinate during mine-site rehabilitation. Laboratory germination trails were conducted to identify dormancy mechanisms and to improve germination response. Treatments applied to all species included scarification and scarification followed by soaking seeds in smoke water (1, 5 or 10%) or gibberellic acid solution (50, 200 or 1000 μM). Additional treatments with kinetin solution (50, 200 or 1000 μM) and smoke water (50 or 100%) were applied to scarified or unscarified seeds of C. corymbosa. Thermal-shock treatment was applied to L. nutans fruit, some of which were subsequently scarified and subjected to both smoke water (10%) and gibberellic-acid solution (1000 μM). Significant germination increases were obtained by using dormancy-breaking treatments on H. commutata (12.8 to 76.0%), H. amplexicaulis (6.8 to 55.1%) and C. corymbosa (48.5 to 86.4%). Scarification alone increased germination of both Hibbertia species, suggesting that these species display a physical seed coat-imposed dormancy mechanism. Germination of H. amplexicaulis was further increased by the application of gibberellic-acid solution, indicating a possible embryo-imposed dormancy mechanism. Scarification followed by the application of smoke water produced the highest germination response for C. corymbosa seeds. Scarification alone did not significantly increase germination, inferring the existence of a smoke-responsive embryo dormancy mechanism. Seeds of L.�nutans, although viable, failed to germinate and are thought to display complex seed coat- and embryo-imposed dormancy mechanisms.

Adenosine triphosphate and adenylate energy charge in relation to dormancy of wild oat seeds

1983 ◽  
Vol 61 (12) ◽  
pp. 3349-3354 ◽  
Author(s):  
Stephen W. Adkins ◽  
James D. Ross
Keyword(s):  
Gibberellic Acid ◽  
Adenosine Triphosphate ◽  
Energy Charge ◽  
Avena Fatua ◽  
The State ◽  
Limiting Factors ◽  
Adenylate Energy Charge ◽  
Wild Oat ◽  
Oat Seeds ◽  
Adenosine Phosphates

Adenosine phosphates, expressed as ATP and energy charge levels, were compared in genetically identical dormant and nondormant caryopses of wild oat (Avena fatua L.). Air-dry nondormant caryopses had a larger pool of ATP and a higher energy charge than dormant caryopses. During the early hours of imbibition of water by dormant caryopses, ATP levels and energy charge increased indicating they are not limiting factors for germination. Moreover, during the induction of germination in dormant caryopses by gibberellic acid (GA3), changes in energy charge were similar to those observed on water, indicating that GA3 does not overcome dormancy simply by elevating energy charge levels. In a second study, ATP and energy charge were measured in initially dormant caryopses incubated under conditions of temperature that either removed or retained dormancy. Both embryo and endosperm extracts demonstrated correlations between levels of ATP or energy charge with temperature of incubation but not with the state of dormancy. The conclusions drawn from both lines of investigation do not support the hypothesis that release of dormancy is related to the metabolism of adenosine phosphates in caryopses of wild oat.

Effects of immersing dry seeds in alkaline solutions on seed dormancy and water uptake in wild oat (Avena fatua)

1994 ◽  
Vol 74 (1) ◽  
pp. 19-24 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson
Keyword(s):  
Seed Dormancy ◽  
Water Uptake ◽  
Seed Coat ◽  
Treatment Time ◽  
Alkaline Treatment ◽  
Avena Fatua ◽  
Alkaline Solutions ◽  
Wild Oat ◽  
Dormancy Breaking ◽  
Breaking Dormancy

Effects of immersing dry seeds in KOH and NaOH solutions on seed dormancy and water uptake were studied in three dormant lines of wild oat (Avena fatua L.). KOH was more effective than NaOH in breaking dormancy. Maximum dormancy-breaking effect of 5.3 N KOH could be achieved with a 10- or 15-min treatment. Increase in treatment time did not necessarily increase germination; rather, it caused damage to the seeds. For 10-min treatment, 5.3 and 7.6 N KOH solutions were more effective than 3 and 9.8 N. Genetic lines responded differently to the KOH treatment. Initial rate and amount of water uptake by KOH-treated seed were significantly higher than by the untreated. It is believed that breaking dormancy by the alkaline treatment is related to removing the barrier to water uptake formed by the seed coat. Key words: Alkalis, Avena fatua, dormancy, seed coat, seedling growth

Hormonal Control of Weed Seed Germination

Weed Science ◽  
1972 ◽  
Vol 20 (3) ◽  
pp. 209-212 ◽  
Author(s):  
R. E. Holm ◽  
M. R. Miller
Keyword(s):  
Seed Germination ◽  
Cyclic Amp ◽  
Gibberellic Acid ◽  
Red Light ◽  
Hormonal Control ◽  
Weed Seed ◽  
Germination Response ◽  
Buried Seeds

Freshly-harvested seeds of several common weeds showed little or no promotion of germination by light. However, after burial for 6 months, germination becomes entirely dependent on exposure to light. Red light promoted the germination of the buried seeds, and this promotion was reversed by far-red light, indicating phytochrome involvement. Freshly-harvested seeds were made light-requiring by treatment with mannitol. The germination of these light-requiring seeds was promoted by red light, gibberellic acid (GA), acetylcholine (ACh), and adenosine 3′,5′-monophosphate (cyclic AMP). The phytochrome response may trigger ACh synthesis which causes the release of GA from a bound form and/or GA synthesis which enhances the production of cyclic AMP which initiates the germination response.

Studies of Achene Dormancy in Fumitory

Weed Science ◽  
1970 ◽  
Vol 18 (3) ◽  
pp. 345-348 ◽  
Author(s):  
Larry S. Jeffery ◽  
John D. Nalewaja
Keyword(s):  
Seed Coat ◽  
Red Light ◽  
Avena Fatua ◽  
Wild Oat ◽  
Embryo Germination ◽  
Water Leaching ◽  
Radicle Growth ◽  
High Concentrations ◽  
Time Required ◽  
Fumaria Officinalis

Fumitory (Fumaria officinalis L.) achenes were subjected to various treatments to induce germination and to study dormancy. Complete pericarp removal, partial seed coat removal, puncturing the seed coat, heat treatment, red and far-red light treatments, and germination temperature treatments did not break dormancy. Low-temperature after-ripening for 60 days at 4 C dormant fumitory achenes resulted in 90 to 95% germination. Water leaching of fumitory achenes increased the time required for successful after-ripening and the water leachate stimulated Avena coleoptile cylinder elongation. Wild oat (Avena fatua L.) embryo germination was inhibited by high concentrations of fumitory achene leachate and stimulated slightly by lower concentrations. High concentrations of the leachate inhibited epicotyl and radicle growth of pre-sprouted lettuce (Lactuca sativa L.) seedlings and lower concentrations markedly stimulated radicle growth.

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