scholarly journals Boron concentration gradient in the endosperm and embryo during ovule development in Clivia miniata

2014 ◽  
Vol 65 (1-2) ◽  
pp. 147-150
Author(s):  
Witold Reczyński ◽  
Marian Ryczkowski ◽  
Urszula Czaja
Keyword(s):  
Concentration Gradient ◽  
Boron Concentration ◽  
Chemical Compounds ◽  
Exponential Phase ◽  
Ovule Development ◽  
Clivia Miniata ◽  
Polar Distribution

Research on boron concentration gradient in the endosperm and embryo of <em>Clivia miniata</em> Regel ovules is a continuation of investigations on polar distribution of several compounds in the developing ovule. The polar distribution of chemical compounds in the ovule might constitute one of the factors determining embryogenesis. It was found that: a) there occured a chalaza-micropyle gradient of boron concentration in the endosperm during the exponential phase of embryo growth (age of ovules - 50 to 120 days); boron concentration in the endosperm increased from 12.13 to 23.71 µg g<sup>-1</sup> fr.wt. (micropylar part) and from 13.58 to 28.42 µg g<sup>-1</sup> fr.wt. (chalazal part); the embryo elongated towards the chalazal part of the ovule, i.e. towards higher boron concentration in the endosperm; b) in the embryo a reversed gradient of boron was detected: a higher concentration in the micropylar part (decrease from 127.29 to 61.78 µg g<sup>-1</sup> fr.wt.; ovules 86-123 days old), a lower one in the chalazal part (decrease from 99.47 to 53.16 µg g<sup>-1</sup> fr.wt.; the exponential phase of embryo growth).

scholarly journals Further observations on the physico-biochemical and physiolo gical gradients in the ovule during embryogenesis

2014 ◽  
Vol 50 (1-2) ◽  
pp. 295-301
Author(s):  
Marian Ryczkowski
Keyword(s):  
Amino Acids ◽  
Respiration Rate ◽  
Opposite Direction ◽  
Free Amino Acids ◽  
Free Amino ◽  
Exponential Phase ◽  
Ovule Development ◽  
Endosperm Tissue ◽  
Clivia Miniata

In the developing ovule (<em>Clivia</em> sp. and <em>Clivia miniata</em>; exponential phase of embryo growth) the following gradients were found: of osmotic value, concentration of free amino acids, respiration rate in the endosperm tissue, and osmotic value and respiration rate gradients in the embryo. Generally these gradients (with the exception of respiration rate in the embryo) were directed from the chalaza to the micropyde i.e. in the opposite direction of the embryo elongation (imicropyle→chalaza). The obtained results suggest of the direction of some gradients can change during the ovule development.

scholarly journals Changes in concentration of protein and nucleic acids in the endosperm during ovule development in Clivia miniata

2014 ◽  
Vol 65 (1-2) ◽  
pp. 141-145
Author(s):  
Marian Ryczkowski ◽  
Tadeusz Bochnia
Keyword(s):  
Nucleic Acid ◽  
Protein Concentration ◽  
Stationary Phases ◽  
Ovule Development ◽  
Concentration Gradients ◽  
Two Phase ◽  
Phase Synthesis ◽  
Dna And Rna ◽  
Clivia Miniata ◽  
Rna Concentration

Changes of protein and nucleic acid concentrations in micropylar and chalazal parts of the endosperm during exponential and stationary phases of embryo growth (<em>Clivia miniata</em> Regel) were examined. The following facts were established: 1. evident two-phase synthesis of protein, DNA and RNA in the endosperm, 2. existence of chalaza-micropyle concentration gradients of analyzed compounds, 3. elongation of the embryo proceedes from the micropylar to the chalazal end of the ovule, i. e. in the direction oposite to that of the chalaza - micropyle protein, DNA and RNA concentration gradients, 4. decrease of concentrations of protein, DNA and RNA in the endosperm after the first maximum of these compounds. Protein concentration was determined spectrophotometricaly using the method of Lowry, RNA concentration was deter-mined with the orcin method, and concentration of DNA with the diphenylamine method.

scholarly journals Asynchrony of ovule primordia initiation in Arabidopsis

Development ◽  
2020 ◽  
Vol 147 (24) ◽  
pp. dev196618
Author(s):  
Shi-Xia Yu ◽  
Lv-Wen Zhou ◽  
Li-Qin Hu ◽  
Yu-Tong Jiang ◽  
Yan-Jie Zhang ◽  
...  
Keyword(s):  
Marker Genes ◽  
Hormone Signaling ◽  
Ovule Development ◽  
Seed Number ◽  
Auxin Response ◽  
New Genes ◽  
Brassinosteroid Signaling ◽  
Ovule Number ◽  
Polar Distribution ◽  
Hormone Signals

ABSTRACTPlant ovule initiation determines the maximum of ovule number and has a great impact on the seed number per fruit. The detailed processes of ovule initiation have not been accurately described, although two connected processes, gynoecium and ovule development, have been investigated. Here, we report that ovules initiate asynchronously. The first group of ovule primordia grows out, the placenta elongates, the boundaries of existing ovules enlarge and a new group of primordia initiates from the boundaries. The expression pattern of different marker genes during ovule development illustrates that this asynchronicity continues throughout whole ovule development. PIN-FORMED1 polar distribution and auxin response maxima correlate with ovule primordia asynchronous initiation. We have established computational modeling to show how auxin dynamics influence ovule primordia initiation. Brassinosteroid signaling positively regulates ovule number by promoting placentae size and ovule primordia initiation through strengthening auxin response. Transcriptomic analysis demonstrates numerous known regulators of ovule development and hormone signaling, and many new genes are identified that are involved in ovule development. Taken together, our results illustrate that the ovule primordia initiate asynchronously and the hormone signals are involved in the asynchrony.

Cytochemical analysis of mast cell granules after poly-dl-lysine action

1978 ◽  
Vol 36 (2) ◽  
pp. 278-279
Author(s):  
R. Courtoy ◽  
L.J. Simar ◽  
J. Christophe
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Chemical Compounds ◽  
Cellular Membrane ◽  
Thin Sections ◽  
Organic Bases ◽  
Ferric Thiocyanate ◽  
Cytochemical Analysis ◽  
Mast Cell Granule ◽  
Amine Liberation

Several chemical compounds induce amine liberation from mast cells but do not necessarily provoque the granule expulsion. For example, poly-dl-lysine induces modifications of the cellular membrane permeability which promotes ion exchange at the level of mast cell granules. Few of them are expulsed but the majority remains in the cytoplasm and appears less dense to the electrons. A cytochemical analysis has been performed to determine the composition of these granules after the polylysine action.We have previously reported that it was possible to demonstrate polyanions on epon thin sections using a cetylpyridinium ferric thiocyanate method. Organic bases are selectively stained with cobalt thiocyanate and the sulfhydryle groups are characterized with a silver methenamine reaction. These techniques permit to reveal the mast cell granule constituents, i.e. heparin, biogenic amines and basic proteins.

Growth of near noble metal Pd and Pt thin film silicides morphology and structure

1984 ◽  
Vol 42 ◽  
pp. 498-499
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh
Keyword(s):  
Noble Metals ◽  
Annealing Temperature ◽  
Chemical Compounds ◽  
Barrier Properties ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Stable Chemical ◽  
Metal Thickness ◽  
Amorphous Si ◽  
Si Films

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.

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