DORMANCY STUDIES IN SEED OF AVENA FATUA: 5. ON THE RESPONSE OF ALEURONE CELLS TO GIBBERELLIC ACID

1966 ◽  
Vol 44 (1) ◽  
pp. 19-32 ◽  
Author(s):  
J. M. Naylor
Keyword(s):  
Amino Acids ◽  
Gibberellic Acid ◽  
Avena Fatua ◽  
Wild Oats ◽  
Aleurone Cells ◽  
Aleurone Tissue ◽  
Primary Action

The synthesis of α-amylase by excised aleurone tissue can be induced by supplying either gibberellic acid (GA) or a mixture of amino acids and sucrose. Aleurone cells form RNA within 4 hours after the imbibition of water or a solution of GA. Synthesis of RNA is essential for the subsequent production of the enzyme. The primary action of GA leading to production of the enzyme begins at about the same time as the first synthesis of RNA. Loss of dormancy during after-ripening involves changes in the response of aleurone cells to gibberellin. Aleurone cells of a non-dormant domestic oat variety Torch exhibit a greater autonomy in the control of α-amylase synthesis than those of wild oats. The current hypothesis that GA acts by genetic derepression is discussed.

Onset of the synthesis of RNA and protein in mature aleurone tissue of wild oats (Avena fatua)

1972 ◽  
Vol 50 (2) ◽  
pp. 305-313 ◽  
Author(s):  
N. Maherchandani ◽  
J. M. Naylor
Keyword(s):  
Protein Synthesis ◽  
Avena Fatua ◽  
Dry Storage ◽  
Wild Oats ◽  
Aleurone Cells ◽  
Aleurone Tissue

Evidence is presented from autoradiographic experiments, indicating that the onset of protein synthesis in newly imbibed mature aleurone cells of Avena fatua L. is independent of the synthesis of "new" RNA. It is concluded that all fractions of RNA which are essential for protein synthesis survive for periods of several weeks, and probably for several years in caryopses held in dry storage. The results are consistent with previous reports of long-lived template-active RNA in mature, dry plant embryos.

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

1990 ◽  
Vol 9 (1-4) ◽  
pp. 35-41 ◽  
Author(s):  
Judith M. Bradow ◽  
William J. Connick ◽  
Armand B. Pepperman ◽  
Lynda H. Wartelle
Keyword(s):  
Gibberellic Acid ◽  
Avena Fatua ◽  
Wild Oats

The effect of sodium hypochlorite and gibberellic acid on seed dormancy and germination of wild oats (Avena fatua)

1979 ◽  
Vol 57 (16) ◽  
pp. 1729-1734 ◽  
Author(s):  
A. I. Hsiao
Keyword(s):  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Sodium Hypochlorite ◽  
Slow Rate ◽  
Avena Fatua ◽  
Germination Inhibitors ◽  
Wild Oats ◽  
Dormancy Induction ◽  
Seed Dormancy And Germination

The seed coverings, including the pericarp and testa of the caryopsis and the hull, arc the main barriers to the exchange of gases and the penetration of exogenous gibberellic acid (GA3) for germination of wild oats (Avena fatua L.). Dormancy was induced in seeds by immersing them in water for 15 minor longer. Dormancy induction was greater in those seeds immersed for up to 1 h in 6% sodium hypochlorite (NaOCl) and then 1 h in water than in those seeds immersed only in water for 1 h. The addition of GA3, to seeds subjected to NaOCl treatment for 15 min or less did not break dormancy, indicating a slow rate of entry, or the exclusion, of GA3, by the seeds. In the presence of GA3, germination increased with increasing exposure to NaOCl. Maximum germination was obtained by immersing dry seeds in NaOCl for 2 h, in water for 1 h, and then incubating the seeds in GA3. Gibberellic acid was not required for complete germination of imbibed, dehulled seeds immersed in NaOCl for 1 h then in water for 1 h, but it was necessary to use 10−4 M GA3 for complete germination of intact seeds that were treated with NaOCl or 2 h then with water for 1 h. Imbibed, dormant seeds that were dehulled and pierced required 10−7 M GA3, to give complete germination in this study. Piercing of the seed coverings enhances GA3, penetration and thus increases the availability of GA3, for germination. NaOCl treatment to the seeds mimics the effects of piercing. NaOCl may also have caused loss of germination inhibitors or rendered these inhibitors susceptible to oxidation. However, prolonged NaOCl treatment resulted in either poor germination or seed disintegration.

Regulation of enzyme synthesis in aleurone tissue of Avena species

1969 ◽  
Vol 47 (12) ◽  
pp. 2069-2072 ◽  
Author(s):  
J. M. Naylor
Keyword(s):  
Amino Acids ◽  
Hydrolytic Enzymes ◽  
Genetic System ◽  
Enzyme Synthesis ◽  
Hormonal Control ◽  
Physiological System ◽  
Avena Species ◽  
Wild Oats ◽  
Aleurone Tissue ◽  
Regulation Of Enzyme Synthesis

Control of the synthesis of α-amylase in isolated aleurone tissue of an inbred population of wild oats and of the domestic oat variety Torch has been compared. Production of the enzyme in wild oats shows much greater dependence on exogenous gibberellic acid or amino acids than in Torch. It is suggested that this difference reflects variability in a genetic system which determines the degree of hormonal control over the synthesis of hydrolytic enzymes in aleurone of Avena species. Natural selection can be expected to maintain genotypes conferring strong hormonal control of this physiological system in wild oats which depend, for survival, on seed dormancy.

VARIABILITY IN DNA CONTENT AND NUCLEAR MORPHOLOGY OF THE ALEURONE CELLS OF AVENA FATUA (WILD OATS)

1971 ◽  
Vol 13 (3) ◽  
pp. 578-584 ◽  
Author(s):  
N. J. Maherchandani ◽  
J. M. Naylor
Keyword(s):  
Nuclear Dna ◽  
General Rule ◽  
Dna Amplification ◽  
Avena Fatua ◽  
Adaptive Function ◽  
Wild Oats ◽  
Aleurone Cells ◽  
Dna Values ◽  
Dna Turnover ◽  
Continuous Range

Nuclei of mature aleurone cells of Avena fatua do not conform to the general rule of DNA constancy. That is, a frequency distribution of nuclear DNA values in aleurone shows a continuous range from less than 2C to greater than 6C, with no accumulation of values at 3C and 6C as expected in a mature triploid tissue.This departure from DNA constancy apparently is not due to irregularity in mitosis. It may reflect DNA turnover or DNA amplification during differentiation. The possible adaptive function of DNA amplification in aleurone is discussed.

Further Experiments on the β-Amylase-Containing Lysosomes of Wheat Aleurone Cells

1975 ◽  
Vol 2 (1) ◽  
pp. 41 ◽  
Author(s):  
RA Gibson ◽  
LG Paleg
Keyword(s):  
Cell Wall ◽  
Gibberellic Acid ◽  
Acid Treatment ◽  
Chelating Agents ◽  
Specific Binding ◽  
Hydrolytic Enzymes ◽  
Supernatant Fraction ◽  
Acid Gas ◽  
Aleurone Cells ◽  
Aleurone Tissue

The presence of hydrolytic enzymes in sedimentable fractions (lysosomes) of homogenized gibberellic acid (GAS)-treated wheat aleurone tissue has been further examined. Non-specific binding of free α-amylase (EC 3.2.1.1) to any organelle did not occur when added before homogenization to aleurone tissue either treated with GA3 or untreated, nor when amylose was added to GA3-treated tissue. The distribution of sedimentable α-amylase between different centrifugal fractions could be controlled, however, by varying the concentrations of calcium or chelating agents in the grinding medium. The concentration of GA*3 applied to aleurone tissue altered neither the percentage nor the distribution of α-amylase recovered in the various particulate fractions. Of the α-amylase appearing in the supernatant fraction, a large proportion appears to be located in the cell wall and is inactivated by acid treatment prior to homogenization, confirming previous reports. Tissue treated in this way yields more than 80% of the recoverable enzyme in sedimentable fractions.

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

1985 ◽  
Vol 63 (10) ◽  
pp. 1789-1793 ◽  
Author(s):  
D. V. Rao ◽  
M. V. S. Raju
Keyword(s):  
Gibberellic Acid ◽  
Epidermal Cell ◽  
Cell Elongation ◽  
Primary Root ◽  
Avena Fatua ◽  
Epidermal Cells ◽  
Wild Oat ◽  
Starchy Endosperm ◽  
Wild Oats

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.

Heterogeneity and Behaviour of Aleurone Cells in the Caryopsis of Wild Oats (Avena fatua)

Flora ◽  
1988 ◽  
Vol 180 (5-6) ◽  
pp. 417-427 ◽  
Author(s):  
M.V.S. Raju ◽  
A. Walther
Keyword(s):  
Avena Fatua ◽  
Wild Oats ◽  
Aleurone Cells
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