scholarly journals Physiological Effects of Gibberellic Acid. IV. On Barley Grain With Normal, X-Irradiated, & Excised Embryos

1962 ◽  
Vol 37 (5) ◽  
pp. 579-583 ◽  
Author(s):  
L. G. Paleg ◽  
D.H.B. Sparrow ◽  
A. Jennings
Keyword(s):  
Gibberellic Acid ◽  
Barley Grain ◽  
Physiological Effects ◽  
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.

scholarly journals PHYSIOLOGICAL CHANGES ASSOCIATED WITH LEAF SENESCENCE IN EASTER LILIES

HortScience ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 189a-189
Author(s):  
Rosanne E. Franco ◽  
Susan S. Han
Keyword(s):  
Gibberellic Acid ◽  
Leaf Senescence ◽  
Growth Regulators ◽  
Cold Storage ◽  
Foliar Application ◽  
Lilium Longiflorum ◽  
Continuous Treatment ◽  
Physiological Effects ◽  
Easter Lily ◽  
The Individual

Senescence of lower leaves of Easter lilies (Lilium longiflorum Thunb.) was previously shown to be delayed with application of the growth regulators, gibberellic acid (GA3) and benzyladenine (BA). This study was done to determine the physiological effects of GA3 and BA in relation to the delay of leaf senescence. Foliar application with 500 ppm BA or GA3 delayed chlorosis and lowered respiration rate in Easter lily leaves. A combination of 500 ppm BA and 500 ppm GA3 was more effective than the individual application of each. Gibberellic acid, BA, or their combination before cold storage resulted in delayed chlorosis and lowered respiration following removal from cold storage. Treatment with growth regulators after cold storage was less effective. Senescence of leaves was not associated with ethylene since ethylene production by leaves was undetectable by gas chromatograph. In addition, pulsing or continuous treatment with silver thiosulphate (STS), an inhibitor of ethylene synthesis, did not delay foliar chlorosis. Analysis of carbohydrate levels in Easter lily leaves treated with GA3, BA, or their combination may contribute to the understanding of the physiological effects of these two growth regulators.

scholarly journals Physiological effects of gibberellic acid. V. Endosperm responses of barley, wheat, & oats

1962 ◽  
Vol 37 (6) ◽  
pp. 798-803 ◽  
Author(s):  
L. G. Paleg ◽  
B. G. Coombe ◽  
M. S. Buttrose
Keyword(s):  
Gibberellic Acid ◽  
Physiological Effects

scholarly journals Physiological Effects of Gibberellic Acid. VI. Other Gibberellins in Three Test Systems

1964 ◽  
Vol 39 (2) ◽  
pp. 286-290 ◽  
Author(s):  
L. Paleg ◽  
D. Aspinall ◽  
B. Coombe ◽  
P. Nicholls
Keyword(s):  
Gibberellic Acid ◽  
Physiological Effects ◽  
Test Systems
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