Embryogenèse somatique du cocotier (Cocos nucifera L.) à partir d'explants foliaires: étude histologique

1992 ◽  
Vol 70 (4) ◽  
pp. 735-741 ◽  
Author(s):  
J. Buffard-Morel ◽  
J. L. Verdeil ◽  
C. Pannetier

Histological studies were carried out at different stages of somatic embryogenesis of coconut (Cocos nucifera L.) from leaf explants. The primary formations resulted from mitotic divisions of perivascular cells. Differentiation of a cambium-like layer insured the growth of nodular calluses. The root origin of some formations was observed. Embryogenic structures appeared on some nodular calluses maintained in culture; initially they were highly meristematic and often developed an epidermis and divided. Then embryo-like formations could be obtained after fragmentation of the cambium-like layer producing meristematic areas. However, modifications of this scheme could be observed: (i) Embryos rapidly developed from a primary callus, and from these embryos, a secondary embryogenesis was induced leading, at the root pole, to a clump of somatic embryos. One of the latter developed a shoot and roots; the regenerated plant was then transferred to the field. (ii) Secondary granulous calluses producing larger quantities of embryogenic structures were formed. This material should prove useful for mastering the technique of developing embryogenic structures. Key words: Cocos nucifera L., histology, somatic embryogenesis, foliar explants.

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 70
Author(s):  
Ana D. Simonović ◽  
Milana M. Trifunović-Momčilov ◽  
Biljana K. Filipović ◽  
Marija P. Marković ◽  
Milica D. Bogdanović ◽  
...  

Centaurium erythraea (centaury) is a traditionally used medicinal plant, with a spectrum of secondary metabolites with confirmed healing properties. Centaury is an emerging model in plant developmental biology due to its vigorous regenerative potential and great developmental plasticity when cultured in vitro. Hereby, we review nearly two decades of research on somatic embryogenesis (SE) in centaury. During SE, somatic cells are induced by suitable culture conditions to express their totipotency, acquire embryogenic characteristics, and eventually give rise to somatic embryos. When SE is initiated from centaury root explants, the process occurs spontaneously (on hormone-free medium), directly (without the callusing phase), and the somatic embryos are of unicellular origin. SE from leaf explants has to be induced by plant growth regulators and is indirect (preceded by callusing). Histological observations and culture conditions are compared in these two systems. The changes in antioxidative enzymes were followed during SE from the leaf explants. Special focus is given to the role of arabinogalactan proteins during SE, which were analyzed using a variety of approaches. The newest and preliminary results, including centaury transcriptome, novel potential SE markers, and novel types of arabinogalactan proteins, are discussed as perspectives of centaury research.


2014 ◽  
Vol 23 (2) ◽  
pp. 147-155 ◽  
Author(s):  
Dinesh Giri ◽  
Sushma Tamta

This protocol has been developed for somatic embryogenesis in Hedychium spicatum. Simultaneously, a method has also been developed for the production of synthetic seeds by using somatic embryos. Direct somatic embryos were developed on cotyledon explants of zygotic embryos on MS supplemented with high concentration of NAA (20.0 µM). Induction of secondary embryogenesis was best in 2,4-D supplemented medium fortified with activated charcoal. Germination of somatic embryos was enhanced by using GA3. Besides this, round and semi-hard beads of somatic embryos (synthetic seeds) could be produced by using 2% Na-alginate and 100 mM calcium chloride and more than 30% germination of synthetic seeds was achieved in MS. Well acclimated plants produced via somatic embryogenesis and/or synthetic seeds were transferred to field where more than 60% survived. This simple study enabled us to obtain a number of plantlets throughout the year each cycle requiring a short period of time. Besides propagation, this study provided an ex situ method for conservation of this vulnerable Himalayan species.D. O. I.http://dx.doi.org/10.3329/ptcb.v23i2.17506Plant Tissue Cult. & Biotech. 23(2): 147-155, 2013  (December)


1970 ◽  
Vol 14 ◽  
pp. 31-38 ◽  
Author(s):  
M Rahman ◽  
M Asaduzzaman ◽  
N Nahar ◽  
MA Bari

Somatic embryos were obtained from cotyledon and midrib explants of Solanum melongena L., cultivar Loda. For callus induction, medium was supplemented with different concentrations of auxin singly or in combination with BAP. The best callusing 83-85% was obtained from both of the explants cultured on MS medium containing 2.0 mgl-1NAA + 0.05 mgl-1BAP. Somatic embryogenesis and shoot regeneration was achieved after transferring the calli to MS medium supplemented with BAP, GA3, NAA and Zeatin. Cotyledon derived calli showed better performance (87%) for regeneration than that of midrib (82%) when sub cultured on MS medium having 2.0 mgl-1 Zeatin + 1.0 mgl-1 BAP. For root induction, MS + 3.0 mgl-1 IBA was proved to be better treatment for average number (14-15) and mean length (12 cm) of roots than those of other treatments. Key words: Eggplant; cotyledon; midrib; callus induction; somatic embryo J. bio-sci. 14: 1-9, 2006


1989 ◽  
Vol 19 (2) ◽  
pp. 285-288 ◽  
Author(s):  
S. A. Merkle ◽  
A. T. Wiecko

Tissue cultures were initiated from developing seeds of black locust (Robiniapseudoacacia L.) collected from three trees at weekly intervals from 1 week following anthesis until early fruit maturity. Explants were cultured on media containing 0, 2, or 4 mg/L 2,4-dichlorophenoxyacetic acid and 0 or 0.25 mg/L 6-benzyladenine. Seeds explanted onto hormone-supplemented media remained on these media for 1 or 3 weeks before being placed on hormone-free media, or were maintained on hormone-supplemented media for the entire study. Direct somatic embryogenesis was observed in a single culture, initiated from a seed collected 4 weeks after anthesis and cultured for 1 week on a medium supplemented with 4 mg/L 2,4-dichlorophenoxyacetic acid and 0.25 mg/L 6-benzyladenine before transfer to basal medium. Although it could not be discerned from which part of the explant somatic embryos were derived, secondary embryogenesis continued from the radicles of cotyledonary-stage somatic embryos. Most somatic embryos were well formed, with two distinct cotyledons. Embryos germinated precociously, producing plantlets that were initially weak but later gained vigor and resembled seedlings.


2015 ◽  
Vol 43 (3) ◽  
Author(s):  
K. Lakshmi Jayaraj ◽  
U. Bhavyashree ◽  
T.P. Fayas ◽  
K.K. Sajini ◽  
M.K. Rajesh ◽  
...  

<div><table cellspacing="0" cellpadding="0" align="center"><tbody><tr><td align="left" valign="top"><p>Since coconut is   one of the most recalcitrant species to generate <em>in vitro</em>, it is   necessary to study in detail about the cellular changes that occur during   somatic embryogenesis to enhance our knowledge about this phenomenon. In the   present study, coconut plumular tissues, the shoot meristem including leaf   primordia, were used as explants for <em>in vitro </em>regeneration studies.   Histological studies were carried out in different stages of plumule culture.   No noticeable growth was observed in 15 days old cultures. After 30 days,   meristematic cells could be identified. Abundance of meristematic cells,   foremost to the development of callus structures, was observed after 45 days.   After 75 days, globular friable calli were formed and histological studies   revealed the presence of meristematic centers which eventually formed somatic   embryos. The histological study of matured somatic embryos formed after 120   days of callus initiation showed a clear meristematic zone of parenchyma   cells, surrounded by vascular bundles. Histological studies, carried out for   certain abnormalities like compact calli, abnormal somatic embryoids with   rudimentary shoots and multiplied roots, revealed the presence of intact   cotyledonary leaves which seemed to inhibit the apical meristem development   of somatic embryoids. The presence of vascular bundles in the early stages of   callus formation might lead to the direct formation of meristemoids. These   results could aid future studies leading to enhanced control of the somatic   embryogenic process and greater efficiency of somatic embryo and plantlet   formation in coconut.</p></td></tr></tbody></table></div>


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jingli Yang ◽  
Songquan Wu ◽  
Chenghao Li

Embryogenic callus was obtained from mature seed explants on medium supplemented with 2,4-dichlorophenoxyacetic acid. Primary somatic embryos (SEs) can only develop into abnormal plants. Well-developed SEs could be obtained through secondary somatic embryogenesis both in solid and liquid cultures. Temperature strongly affected induction frequency of secondary embryogenesis. Relatively high temperature (30∘C) and germinated SEs explants were effective for induction of secondary somatic embryos, and low temperature (20∘C) was more suitable for further embryo development, plantlet conversion, and transplant survival. Somatic embryos formed on agar medium had larger cotyledons than those of embryos formed in liquid medium. Supplementing 0.1 mg L−16-benzyladenine (BA) was effective for plant conversion; the rate of plant conversion was 43.3% in somatic embryos from solid culture and 36.5% in embryos from liquid culture.In vitroplants were successfully acclimatized in the greenhouse. The protocol established in this study will be helpful for large-scale vegetative propagation of this medicinal tree.


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