scholarly journals Stimulation of Endomitotic DNA Synthesis and Cell Elongation by Gibberellic Acid in Epicotyls Grown from Gamma-irradiated Pea Seeds

1980 ◽  
Vol 65 (1) ◽  
pp. 13-16 ◽  
Author(s):  
Alfons Callebaut ◽  
Patrick Van Oostveldt ◽  
Roger Van Parijs
Keyword(s):  
Gibberellic Acid ◽  
Dna Synthesis ◽  
Cell Elongation ◽  
Pea Seeds ◽  
Gamma Irradiated ◽  
Stimulation Of

scholarly journals Role of gibberellins and cytokinins in regulation of germination during development and ripening of Triticale caryopses

2014 ◽  
Vol 53 (2) ◽  
pp. 257-270 ◽  
Author(s):  
Stanisław Weidner
Keyword(s):  
Abscisic Acid ◽  
Gibberellic Acid ◽  
Significant Influence ◽  
Cell Elongation ◽  
Initial Period ◽  
Triticale Caryopses ◽  
Developmental Phases ◽  
Premature Germination ◽  
Stimulation Of

The germination of caryopses of M-T3 <em>Triticale</em> generation, which were freshly harvested in different growth and developmental phases has been studied. A significant influence of the abscisic acid (ABA) accumulation on the increment of number of germinating caryopses has been found. Already in the first phase af the embryogenesis considerable stimulating effects of kinetin and gibberellin-A<sub>3</sub> (GA<sub>3</sub>) on the germination of embryos which were isolated from freshly collected grains have been shown. When both stimulators were used together marked synergetic reaction occurred. It has been also determined that in the initial period of embryogensis premature germination occurs, to a higher extent, under the action of cytokinins than! Whether in the further phases of the caryopse development, when embryo develop mainly through the cell elongation, mostly gibberellins seem to be responsible for the activation of germination processes. The more mature were seeds the quicker germinated whole caryopses and embryos isolated from them at different ripeness, after 3-month storage. The highest stimulation of germination by phytohormones has been found for the most mature caryopses. The action of gibberellic acid has been particulary strong.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

Role of plasma membranes in stimulation of RNA-directed DNA synthesis

Nature ◽  
1976 ◽  
Vol 262 (5571) ◽  
pp. 805-807 ◽  
Author(s):  
L. C. PADHY ◽  
S. K. KAR ◽  
K. K. RAO ◽  
M. R. DAS
Keyword(s):  
Dna Synthesis ◽  
Plasma Membranes ◽  
Stimulation Of

Effects of Kaurane Diterpene Derivatives on Germination and Growth of Lactuca sativa Seedlings

2005 ◽  
Vol 60 (1-2) ◽  
pp. 72-78 ◽  
Author(s):  
Henriete S. Vieira ◽  
Jacqueline A. Takahashi ◽  
Lúcia P. S. Pimenta ◽  
Maria Amélia D. Boaventura
Keyword(s):  
Gibberellic Acid ◽  
Lactuca Sativa ◽  
Naturally Occurring ◽  
Germination And Growth ◽  
Stimulation Of

Kaurenoic and grandiflorenic acid, isolated from Wedelia paludosa (Asteraceae), some derivatives from these acids (alcohols, esters, amides, lactones, oximes) and other naturally occurring kaurane diterpenes were tested for their action on the growth of radical and shoot of Lactuca sativa. Gibberellic acid, GA3, a commercially available phytohormone, belonging to the same class of diterpenes, was also tested. Some of the tested substances showed a remarkable activity either in the inhibition or in stimulation of L. sativa growth. The activity, in some cases, was even higher than that of GA3.

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