Effect of chilling and gibberellic acid on growth potential of excised embryos of Ruellia humilis

Planta ◽  
1971 ◽  
Vol 100 (4) ◽  
pp. 365-369 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Gibberellic Acid ◽  
Growth Potential ◽  
Ruellia Humilis ◽  
Excised Embryos

THE EFFECT OF GIBBERELLIN AND TEMPERATURE ON THE GERMINATION OF SEED OF BELLS OF IRELAND

1963 ◽  
Vol 43 (4) ◽  
pp. 522-527 ◽  
Author(s):  
J. G. S. Trelawny ◽  
D. J. Ballantyne
Keyword(s):  
Gibberellic Acid ◽  
Naphthaleneacetic Acid ◽  
Untreated Seed ◽  
Intact Seed ◽  
Excised Embryos

Gibberellic acid (GA) at constant temperatures partially replaced the alternate temperatures required to break dormancy of intact seed of Bells of Ireland (Moluccella laevis L.). In the presence of GA optimum germination occurred at 10 °C. and declined to almost nil at 25 °C. When 2-naphthaleneacetic acid (NAA) at 10−5 M. was combined with GA the effect on germination at 20 °C. was synergistic. Higher concentrations of NAA antagonized the stimulatory effect of GA. All excised embryos germinated whether from chilled or unchilled seed. Embryos with attached endosperms from chilled seed showed a marked increase in germination over those from unchilled seed. GA induced 100 per cent germination of embryos with attached endosperms, irrespective of chilling, at 20 °C, but not at 25 °C. The presence of the pericarp completely prevented the germination of untreated seed at constant temperatures. Chilling whole seeds for 6 weeks at 5 °C. greatly enhanced penetration of external solutions to the embryo.

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.

DORMANCY STUDIES IN SEED OF AVENA FATUA: 3. A RELATIONSHIP BETWEEN MALTASE, AMYLASES, AND GIBBERELLIN

1962 ◽  
Vol 40 (12) ◽  
pp. 1659-1673 ◽  
Author(s):  
G. M. Simpson ◽  
J. M. Naylor
Keyword(s):  
Energy Source ◽  
Gibberellic Acid ◽  
Avena Fatua ◽  
Starch Granules ◽  
Raw Starch ◽  
Endosperm Starch ◽  
Hydrolysis Of ◽  
Exogenous Sugar ◽  
Excised Embryos

Initiation of germination in excised embryos requires an exogenous energy source. Normally this is obtained from the endosperm. In dormant seeds the hydrolysis of starch is blocked despite the fact that dormant and non-dormant seeds contain similar amounts of α- and β-amylases. Alone or in combination the amylases are unable to break down raw endosperm starch granules to simple sugars in vitro. Exogenous maltase in combination with α-amylase hydrolyzes raw starch to glucose. Exogenous maltase eliminates the requirement for exogenous sugar. Examination of the maltase content of imbibed dormant and non-dormant seeds showed a marked increase in non-dormant seeds during the first 40 hours. This does not occur in dormant seeds unless they are treated with gibberellic acid. The results lead to the conclusion that an important effect of gibberellic acid is to induce the synthesis of maltase or in some way activate the preformed enzyme.

Combined effects of hormones and light during growth promotion in primary leaves of Phaseolus vulgaris

1993 ◽  
Vol 71 (3) ◽  
pp. 501-505 ◽  
Author(s):  
Thomas G. Brock
Keyword(s):  
Cell Wall ◽  
Phaseolus Vulgaris ◽  
Gibberellic Acid ◽  
White Light ◽  
Osmotic Potential ◽  
Leaf Growth ◽  
Growth Potential ◽  
Combined Effects ◽  
Osmotic Concentration ◽  
Yield Threshold

Cell enlargement in primary leaves of bean is promoted by bright white light, gibberellic acid, or the cytokinin N6-benzyladenine. I examine the combined effects of light and hormones on growth, cell wall properties, and osmotic parameters during growth over 24 h. Applied alone, benzyladenine (10 μM), gibberellic acid (10 μM), and white light produced similar increases in the length and fresh weight of excised leaf strips over 24 h. The combined effects of hormones and light on growth were much less than additive. Individually, all three treatments significantly increased cell wall plastic extensibility over 24 h. However, benzyladenine combined with white light were additive in effect on plastic extensibility, and gibberellic acid combined with white light were synergistic. The differences in effects of hormones in white light on growth versus plastic extensibility indicate a decrease in growth potential, which is attributable in part to hormonal effects on osmotic concentration. Although white light alone increased osmotic concentration, both benzyladenine and gibberellic acid greatly decreased it, with or without white light. Furthermore, because growth potential is a function of both osmotic potential and wall yield threshold, it appears that yield threshold does not decline in parallel with osmotic potential in hormone-treated bean leaf strips. Finally, both benzyladenine and gibberellic acid inhibit the increase in osmotic solutes normally produced by white light. This effect, coupled with water uptake during cell expansion, would produce the observed decreases in osmotic concentration in hormone-treated strips. Hence, both benzyladenine and gibberellic acid interfere with light-induced growth, primarily through effects on the apparent ability of light to direct solute accumulation. Key words: Phaseolus vulgaris, leaf growth, cytokinin, gibberellic acid, light.

scholarly journals Seed Dormancy in Eastern Redbud (Cercis canadensis)

1991 ◽  
Vol 116 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Robert L. Geneve
Keyword(s):  
Gibberellic Acid ◽  
Phosphoric Acid ◽  
Seed Dormancy ◽  
Penetration Resistance ◽  
Growth Potential ◽  
Water Imbibition ◽  
Embryonic Growth ◽  
Cercis Canadensis ◽  
Eastern Redbud

Seed dormancy in Eastern redbud (Cercis canadensis var. canadensis L.) can be overcome by seedcoat scarification to allow water imbibition, followed by chilling stratification to permit germination. During chilling stratification, there was an increase in the growth potential of the embryo as indicated by the ability of the isolated embryo to germinate in osmotic solutions. Penetration resistance of the testa also decreased after chilling stratification. The combination of seedcoat alteration and the increase in embryonic growth potential was associated with overcoming dormancy in redbud seed. GA3 or ethephon (50 μm) stimulated germination (28% and 60%, respectively) and increased the growth potential of treated embryos. Chemical names used: gibberellic acid (GA3), (2-chloroethyl) phosphoric acid (ethephon).

Bioassay of Gibberellic Acid using Excised Embryos of Avena fatua L.

Nature ◽  
1961 ◽  
Vol 192 (4803) ◽  
pp. 679-680 ◽  
Author(s):  
J. M. NAYLOR ◽  
G. M. SIMPSON
Keyword(s):  
Gibberellic Acid ◽  
Avena Fatua ◽  
Excised Embryos

Increased participation of pentose phosphate pathway in response to afterripening and gibberellic acid treatment in caryopses of Avena fatua

1971 ◽  
Vol 49 (10) ◽  
pp. 1833-1840 ◽  
Author(s):  
J. A. Simmonds ◽  
G. M. Simpson
Keyword(s):  
Oxygen Consumption ◽  
Gibberellic Acid ◽  
Pentose Phosphate Pathway ◽  
Qualitative Change ◽  
Pentose Phosphate ◽  
Avena Fatua ◽  
Starch Degradation ◽  
Phosphogluconate Dehydrogenase ◽  
Key Enzyme ◽  
Excised Embryos

The rates of oxygen consumption of dormant and non-dormant excised embryos of Avena fatua L. before germination are similar. Gibberellic acid (GA) treatment stimulates germination of dormant embryos without affecting oxygen consumption. Thus dormancy is not the result of restricted oxygen uptake. The fat content of dormant and non-dormant caryopses remains constant during germination. Dormant and non-dormant embryos have respiratory quotients near unity supporting the hypothesis that starch degradation occurs before germination. 6-Phosphogluconate dehydrogenase, a key enzyme of the pentose phosphate pathway, is present in dormant and non-dormant dry embryos but the pre-germination C6/C1 ratio of non-dormant embryos is markedly lower than that of dormant embryos, indicating a greater participation of the pentose phosphate pathway in the respiratory metabolism of non-dormant embryos. Release from dormancy is associated with a shift in metabolism from the glycolytic pathway to the pentose phosphate pathway. GA treatment, which stimulates germination of dormant embryos, causes a similar qualitative change in the oxidative metabolism of dormant embryos. Thus the action of GA is to cause the increased degradation of glucose via the pentose phosphate pathway, which is an essential step in the preparation for germination.

scholarly journals (243) Ovule and Embryo Culture of × Chitalpa tashkentensis Hybrids

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1003D-1003
Author(s):  
Richard T. Olsen ◽  
Thomas G. Ranney ◽  
Zenaida Viloria
Keyword(s):  
Gibberellic Acid ◽  
Embryo Culture ◽  
Coconut Water ◽  
Embryo Germination ◽  
Medium Components ◽  
Final Study ◽  
Petri Dishes ◽  
All Treatment ◽  
Excised Embryos

A series of studies were conducted to determine medium components necessary for ovule and embryo culture of ×Chitalpatashkentensis Elias & Wisura hybrids in order to improve recovery of interploid crosses. Ovules were collected at 2, 3, 4, 5, and 6 weeks after pollination (WAP) from selfed tetraploid × Chitalpa (S) and tetraploid × Chitalp × diploid Catalpabignonioides Walt. (3×) hybrids. Excised ovules were placed in petri dishes with Schenk and Hildebrandt (SH) medium and 0.7% agar, with or without coconut-water (2%) and three sucrose concentrations (20, 40, or 80 g·L-1). No ovules germinated for either cross in any treatment at 2, 3, and 4 WAP. Selfed ovules germinated at 5 WAP, in both 20 and 40 g·L-1 sucrose. At 6 WAP, 3× ovules germinated in 20 g·L-1 sucrose. Coconut water provided no apparent benefit. Embryos were apparent at 6 WAP, so a new study was initiated to compare ovule vs. embryo culture at this sample date. Excised embryos germinated in greater percentages than ovules, in all treatment combinations at 6 WAP. Germination in 80 g·L-1 sucrose was observed only for S embryos without coconut water. Greatest 3× germination (16.7%) was observed for embryos in 20 g·L-1 sucrose without coconut water. A final study was conducted to investigate the effect of gibberellic acid (GA3) on embryo germination. Embryos were harvested at 7 WAP for both crosses and grown in SH medium supplemented with 20 g·L-1 sucrose and 0, 1, 2, or 4 μm GA3. The addition of GA3, regardless of concentration, increased germination from 30.6% to 99.1% for S embryos and from 11.1% to 99.1% for 3× embryos.

Germination of drupelets in multi-seeded drupes of the shrub Leptecophylla tameiameiae (Ericaceae) from Hawaii: a case for deep physiological dormancy broken by high temperatures

2005 ◽  
Vol 15 (4) ◽  
pp. 349-356 ◽  
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin ◽  
Alvin Yoshinaga ◽  
Ken Thompson
Keyword(s):  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Cold Stratification ◽  
Long Period ◽  
Subtype B ◽  
Physiological Dormancy ◽  
To Come ◽  
Subtype A ◽  
Number Of Seeds ◽  
Excised Embryos

This study addressed the difficulty of germinating drupelets (hereafter seeds) in the multi-seeded stony dispersal units (drupes) of Leptecophylla tameiameiae (Ericaceae). Embryos in fresh seeds were 77% the length of the endosperm, and seeds inside the intact drupes imbibed water. We monitored germination at 15/6, 20/10 and 25/15°C for 162 weeks, after which each drupe was cut open and ungerminated seeds counted. Drupes contained 1–6 seeds, and the total number of seeds in all treatments and controls was 1977, with 20, 29, 25, 18, 7 and <1% of them occurring in one-, two-, three-, four-, five- and six-seeded drupes, respectively. The percentage of seeds germinating in one-, two-, three-, four-, five- and six-seeded drupes was 74, 66, 65, 72, 56 and 0, respectively. Neither warm nor cold stratification for 6 or 12 weeks significantly increased germination percentages, compared to controls incubated continuously at 25/15°C for 162 weeks, where 72% of the seeds in the drupes germinated. At 25/15°C, 24–49 weeks were required for 20% of the seeds to germinate. Warm followed by cold stratification did not promote germination, and there was no widening of the temperature range for germination. Like seeds of other species known to have deep physiological dormancy (PD), those of L. tameiameiae required extended periods of time (16 to ≥162 weeks) to come out of dormancy and germinate, gibberellic acid (GA3) did not promote germination and excised embryos failed to grow. Thus, we conclude that seeds of L. tameiameiae have deep PD. However, unlike seeds of other species with deep PD, those of L. tameiameiae required an extensive period of warm rather than of cold stratification to come out of dormancy. It is suggested that a subtype a (seeds require a long period of cold stratification to come out of dormancy) and a subtype b (seeds require a long period of exposure to warm stratification to come out of dormancy) of deep PD be recognized in the Nikolaeva formula system for classifying seed dormancy.

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