Localisation par autoradiographie de l'acide [5-3H]indole-3-acétique dans le bourgeon terminal du Lycopersicum esculentum

1984 ◽  
Vol 62 (6) ◽  
pp. 1149-1157 ◽  
Author(s):  
D. Driss-Ecole ◽  
G. Perbal ◽  
Y. Leroux
Keyword(s):  
Total Radioactivity ◽  
Lycopersicum Esculentum ◽  
Meristematic Cells ◽  
Differentiated Cells ◽  
Apical Bud ◽  
Ethylcarbodiimide Hydrochloride ◽  
Meristematic Activity ◽  
Sieve Tubes ◽  
Whole Plants ◽  
Label Distribution

[3H]indoleacetic acid (AIA) was applied to the shoot tip of intact young plants of Tomato (Lycopersicum esculentum Mill.) for 10, 60, or 120 min. Autoradiograms of whole plants were prepared and liquid scintillation counts of stem segments and principal root segments were performed. Chromatographic analysis showed that 66% of the radioactivity was associated with AIA after 120 min of contact with [3H]AIA. Autoradiographs of semithin and ultrathin sections were prepared after treatment by DCC (1-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide hydrochloride). The quantity of label per cell and the density of label were determined for all tissues of the apical bud. The density of label was greater for meristematic cells than for differentiated cells. The observed homogeneity of label distribution in the apical meristem shows that auxin levels do not play a prominent role in distinguishing between its lateral and axial zones. The density of label was similar in the apical and in the axillary bud of leaf 4. The cells of the rib meristem, which elongate to produce pith, were more intensely labelled than the other meristematic cells. The percentage of label was calculated for each tissue in a transverse section of the stem just below the apex. The amount of auxin was greatest in the parenchyma (axial and cortical) with lesser amounts in the procambium, phloem parenchyma, and xylem parenchyma. Vessels, which had the greatest density of label, did not contain more than about 3% of total radioactivity of the stem section, while sieve tubes had only 0.5%. Pathways of auxin transport and the role of AIA in regulating meristematic activity in the apical bud are discussed.

scholarly journals Establishment and triterpenoid production of Ocimum basilicum cambial meristematic cells

2020 ◽  
Vol 143 (3) ◽  
pp. 573-581
Author(s):  
Alexander Mehring ◽  
Janik Haffelder ◽  
Jonas Chodorski ◽  
Judith Stiefelmaier ◽  
Dorina Strieth ◽  
...  
Keyword(s):  
Ursolic Acid ◽  
Oleanolic Acid ◽  
Biomass Accumulation ◽  
Ocimum Basilicum ◽  
Meristematic Cells ◽  
Cultivation Period ◽  
Shake Flasks ◽  
Valuable Compounds ◽  
Whole Plants ◽  
First Time

AbstractThe application of plant suspension culture to produce valuable compounds, such as the triterpenoids oleanolic acid and ursolic acid, is a well-established alternative to the cultivation of whole plants. Cambial meristematic cells (CMCs) are a growing field of research, often showing superior cultivation properties compared to their dedifferentiated cell (DDC) counterparts. In this work, the first-time establishment of O. basilicum CMCs is demonstrated. DDCs and CMCs were cultivated in shake flasks and wave-mixed disposable bioreactors (wDBRs) and evaluated regarding triterpenoid productivity and biomass accumulation. CMCs showed characteristic small vacuoles and were found to be significantly smaller than DDCs. Productivities of oleanolic and ursolic acid of CMCs were determined at 3.02 ± 0.76 mg/(l*d) and 4.79 ± 0.48 mg/(l*d) after 19 days wDBR cultivation, respectively. These values were consistently higher than any productivities determined for DDCs over the observed cultivation period of 37 days. Elicitation with methyl jasmonate of DDCs and CMCs in shake flasks resulted in increased product contents up to 48 h after elicitor addition, with the highest increase found in CMCs at 232.30 ± 19.33% (oleanolic acid) and 192.44 ± 18.23% (ursolic acid) after 48 h.

scholarly journals Clonal propagation of Trichocentrum stramineum (Orchidaceae), a threatened species endemic to Mexico

2020 ◽  
Vol 98 (2) ◽  
pp. 355-365
Author(s):  
Selene Ramos-Ortiz ◽  
Luz Ma. Rangel-Guerrero ◽  
Martha Elena Pedraza-Santos ◽  
Víctor Manuel Chávez-Ávila ◽  
José Guadalupe Martínez-Ávalos ◽  
...  
Keyword(s):  
Survival Rate ◽  
Clonal Propagation ◽  
Basal Medium ◽  
Botanical Garden ◽  
Genetic Characteristics ◽  
Orchid Species ◽  
Apical Bud ◽  
Whole Plants ◽  
Study Species

Background: Cloning techniques are applied to an endangered orchid species in order to reproduce individual plants and to preserve their genetic characteristics. Objectives: To establish a new protocol for clonal propagation of a threatened orchid of horticultural importance. Study species: Trichocentrum stramineum, a threatened orchid endemic to Mexico. Study site and duration: Totutla, Veracruz, Mexico. All experiments were designed and carried out at the Botanical Garden-UNAM and the IIAF-UMSNH over a course of six years. Methods: Seeds were germinated in a modified KC basal medium; protocorms and apical bud explants were obtained from the resulting in vitro plants and cultivated with or without plant growth regulators (PGRs). Both experimental groups were subcultured in order to evaluate the number of protocorm-like bodies (PLBs) and buds per explant. Results: On average, protocorms generated 51.2 and 54.1 PLBs in the absence or presence of 1 mg l-1 6-benzyladenine (BA), respectively, while 13.1 and up to 23.7 PLBs and / or shoots were observed on the apical bud explants in the absence or presence of 1 mg l-1 kinetin, respectively. In both cases, responses were direct, without the formation of an intervening callus. Approximately 200 PLBs were subcultured and developed into whole plants within 14 weeks. These were acclimatized to greenhouse conditions with a 90 % survival rate after 12 weeks. After 44 weeks, flowering was observed (3 %) individuals measuring at least 12 cm in height. Conclusions: The developed protocol proved to hold great potential for commercial propagation and conservation programs.

Differentiation of bud meristems and cataphylls during adventitious bud formation on embryos of Picea abies

1989 ◽  
Vol 67 (2) ◽  
pp. 422-428 ◽  
Author(s):  
Sara Von Arnold ◽  
Chris Hawes
Keyword(s):  
Picea Abies ◽  
Adventitious Bud ◽  
Bud Formation ◽  
Meristematic Cells ◽  
Cell Divisions ◽  
Adventitious Bud Formation ◽  
Cytokinin Treatment ◽  
Meristematic Activity ◽  
Xylem Elements ◽  
Needle Primordia

Embryos of Picea abies were pulse-treated with benzyladenine for 24 h and then cultured on medium lacking growth regulators. Meristemoids developed on all embryos during the 2nd week after the cytokinin treatment. Cells within the meristemoids divided randomly. As the meristemoids developed, further cell divisions became more organized so that separate regions of meristematic activity could be distinguished within each meristemoid. These meristematic regions developed into individual nodules and each nodule developed further into either a bud meristem or a cataphyll. Cataphylls were composed of unorganized, vacuolated, thick-walled cells whereas bud meristems were composed of organized meristematic cells. Later, xylem elements developed at the base, and needle primordia at the top of bud meristems. The bud apex had cytohistological zonation typical of conifers. The appearance of the developing adventitious buds depended on the number of cataphylls formed per bud as well as on the marginal expansion of the cataphylls.

Les teneurs ioniques des plants d'Isoetes setacea au cours de la réactivation par réhydratation

1986 ◽  
Vol 64 (10) ◽  
pp. 2171-2177
Author(s):  
N. Michaux-Ferrière
Keyword(s):  
Water Stress ◽  
Drought Resistance ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Normal Growth ◽  
Active Metabolism ◽  
Meristematic Cells ◽  
Differentiated Cells ◽  
Whole Plant ◽  
Different Parts

Ionic amounts of S, P, K+, Ca2+, and Mg2+ have been determined by chemical measures in different parts of Isoetes setacea (shoot apical meristem, cortical zone, and central stele) for plants in normal growth, in drought resistance, and during rehydration. Study of modifications in the ionic amounts during experimental rehydration showed that the significant increase of K+, Ca2+, and Mg2+ by the 24th h of experimentation was one of the earliest signals observed for the cells of the apical meristem (which are at that time blocked in G1 presynthesis phase) as well as for the differentiated cells. By the 7th day of rehydration, just before their entrance into the synthesis phase, meristematic cells have recovered ionic rates equivalent to those measured for active plants. The same thing happens in the nonmeristematic tissues. This increase of ionic amounts in the whole plant can be explained by a differential entrance of ions with water. This new balance of the ionic amounts according to the pattern found in the active plants can be considered as a prerequisite event for the recovery of an active metabolism for a meristematic or differentiated cell in water stress.

Influence de la température sur la floraison du Lis blanc

1978 ◽  
Vol 56 (1) ◽  
pp. 110-120 ◽  
Author(s):  
Simonne Rivierè
Keyword(s):  
Apical Meristem ◽  
The Other ◽  
Cold Period ◽  
Biological Cycle ◽  
Full Bloom ◽  
Meristematic Cells ◽  
Meristematic Activity ◽  
Combined Actions ◽  
Aerial Stem ◽  
First Time

The influence of thermoperiodic variations on the flowering of Lilium candidum is discussed here for the first time. Our experimentation was guided by our prior knowledge of the state of the apical meristem during the biological cycle. We concluded that forcing, to be effective, must occur on growing bulbs when the meristem of the lily is in the intermediate phase.We analyzed whether a cold period was necessary. When lily plants were cultivated for 8 days at 2 °C, the meristem reached the prefloral state at the beginning of the warm period (15 °C) which followed. The inflorescence is then in full bloom during the hot period (22 °C). Flowering occurs at the end of February.However, if the cold period is eliminated (with no change in the other periods), the terminal meristem loses its activity and differentiates. It is replaced by a small cluster of meristematic cells. A bulb develops at the top of the stem replacing the inflorescence. In this case, meristematic activity now begins at the axil of the leaves and the aerial stem. The axillary buds thus produced are a result of the combined actions of suppression of apical dominance after the loss of terminal meristem activity and the application of hot temperatures (22 °C).

scholarly journals Synchrony of Inflorescence Initiation and Shoot Growth in Selected Protea Cultivars

2001 ◽  
Vol 126 (2) ◽  
pp. 182-187 ◽  
Author(s):  
Audrey I. Gerber ◽  
Karen I. Theron ◽  
Gerard Jacobs
Keyword(s):  
Apical Meristem ◽  
Shoot Growth ◽  
Flower Initiation ◽  
Apical Bud ◽  
Meristematic Activity ◽  
Floral Primordia ◽  
Appendage Formation ◽  
Floral Bracts ◽  
Insight Into ◽  
Flowering Process

Protea L. sp. can be assigned to groups according to similar times of flower initiation and harvest. The stages occurring during flower initiation and their synchrony relative to shoot growth were investigated for three cultivars when flower initiation occurred on the spring growth flush. For all three cultivars, the spring flush was preformed and enclosed in the apical bud before spring budbreak. During elongation of the spring flush, the apical meristem produced floral primordia which differentiated into involucral bracts. After completion of the spring flush, meristematic activity continued and produced floral bracts with florets in their axils. The different cultivars were characterized by differences or similarities in the time of budbreak, and the rates of shoot growth, appendage formation, and flower development. Insight into the time of flower initiation relative to vegetative growth could be useful in making management decisions, as well as forming a basis for manipulation of the flowering process.

Telomere arrangement in differentiated interphase cells of Allium cepa: a function of chromosome arm lengths at anaphase–telophase

1983 ◽  
Vol 25 (5) ◽  
pp. 478-486 ◽  
Author(s):  
Catharine P. Fussell
Keyword(s):  
Nuclear Envelope ◽  
Allium Cepa ◽  
Interphase Nucleus ◽  
Interphase Nuclei ◽  
Meristematic Cells ◽  
Differentiated Cells ◽  
Allium Cepa L ◽  
Interphase Cells ◽  
Chromosome Arm ◽  
Latitudinal Band

The arrangement of telomeres in eight types of differentiated Allium cepa L. interphase cells was studied to find whether the distribution pattern varies with differentiation as centromere distribution appears to in differentiated cells of mice and Triturus vulgaris L. The results show that telomere positions and groupings in A. cepa are essentially the same in differentiated and meristematic interphase nuclei; telomeres, which are roughly paired, are arranged in a telophase configuration along one side of the nucleus. Thus telomeres appear to maintain the same basic arrangement in differentiated and in meristematic cells. Comparison of chromosome arm lengths and interphase telomere positions suggests that interphase telomere arrangements are a function of chromosome arm lengths at the time the nuclear envelope forms. Such an arrangement would place homologous telomeres in the same latitudinal band of the interphase nucleus.

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