Ultrastructural Changes in Coconut Calli Associated with the Acquisition of Embryogenic Competence

Verdeil, Jean‐Luc; Hocher, Valérie; Huet, C.; Grosdemange, Frédérique; Escoute, Jacques; Ferrière, Nicole; Nicole, Michel

doi:10.1006/anbo.2001.1408

Cited by 126 publications

(125 citation statements)

References 39 publications

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“…Similar structures were observed during in vitro induction of somatic embryogenesis, androgenesis and organogenesis in different species (reviewed in refs. [7][8][9][10][11][12][13].…”

mentioning

confidence: 99%

Are extracellular matrix surface network components involved in signalling and protective function?

Popielarska-Konieczna

Kozieradzka-Kiszkurno²,

Swierczynska³

et al. 2008

Plant Signaling & Behavior

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Endosperm is an interesting model for in vitro experiments, because of its unique origin, development and ploidy level. Here we used Actinidia deliciosa endosperm-derived callus to investigate morphology, histology and chemistry of extracellular matrix (ECM) structures in morphogenically stable tissue from long-term culture. SEM and TEM analysis showed that ECM is a heterogenous layer which consists of amorphous, dark-staining material, osmiophilic granules and reticulated fibres outside the outer callus cell wall. This structure may serve as a structural marker of morphogenic competence in endosperm-derived callus, because of its presence on the surface of callus forming morphogenic domains and its disappearance during organ growth. Based on immunolabelling, histochemistry, solvent and enzyme treatments, we suggest that pectins and lipids are components of the ECM layer. These results might indicate protective, water retention and/or cell communication functions for this ECM layer.In several plants cultured in vitro, SEM analysis revealed that induction of morphogenesis is linked to the appearance of a fibrillar network referred to as the extracellular matrix surface network (ECMSN). 1 Šamaj et al., 2,3 reported, that the ECMSN plays an important morphoregulatory role during somatic embryogenesis and organogenesis, implying an active role in plant morphogenesis. According to Bobák et al., 4 the chemical composition and structural arrangement of the ECMSN on the cell surface indicate that it may play a fundamental role in cell-to-cell recognition and interaction, cell division and differentiation, and also in generation and maintenance of some traits in plant cell populations. There is not a large body of data confirming the occurrence of ECM during in vitro organogenesis. 5,6 Most data concern the formation, structure and chemical composition and function of ECM in somatic and androgenic embryogenesis (reviewed in refs. 6-10). In previous histological and SEM analysis of morphogenic endosperm-derived callus of A. deliciosa, we described the presence of a membranous layer covering the callus surface, which we termed extracellular matrix (ECM). 11 The present experiments employed SEM, TEM and histochemical analysis to study the structure and composition of material coating the callus surface.SEM revealed the presence of heterogeneous material covering the callus surface. A smooth membranous layer coated some parts of the callus surface (Fig. 1A), while other regions were covered by fibrillar structures and granules of mucilage-like secretion forming a network at site of cell-cell adhesion. Similar structures were observed during in vitro induction of somatic embryogenesis, androgenesis and organogenesis in different species (reviewed in refs. 7-13).TEM showed a layer composed of amorphous material with fibrillar and spherical components covering morphogenic cell clusters. The cell wall of non-embryogenic and senescent cells was also covered with ECM, but it differed in appearance: the layer was granular, with amo...

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“…Similar structures were observed during in vitro induction of somatic embryogenesis, androgenesis and organogenesis in different species (reviewed in refs. [7][8][9][10][11][12][13].…”

mentioning

confidence: 99%

Are extracellular matrix surface network components involved in signalling and protective function?

Popielarska-Konieczna

Kozieradzka-Kiszkurno²,

Swierczynska³

et al. 2008

Plant Signaling & Behavior

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“…Embryogenic cells were minute, resembled meristematic cells, displayed more densely staining nuclei and nucleoli, denser cytoplasm and starch grains, and a thick cell wall. Such walls are characteristic of somatic embryo formation (Canhoto & Cruz, 1996;Canhoto et al, 1999;Verdeil et al, 2001), which is quite clear in Fig. 3b, 3d.…”

Section: Discussionmentioning

confidence: 72%

In vitro regeneration of Didymopanax morototoni

2006

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The present study aimed at establishing a complete plant regeneration protocol for Didymopanax morototoni (matchwood), a native Brazilian forest species. Four types of explants (root, shoot, node, and cotyledonary leaves) were obtained from in vitro germinated seeds. In the first step, woody plant medium (WPM) with casein hydrolysate (250 mgL ). Twenty days after inoculation, the material was evaluated. Embryogenic calli were split, transferred to expression medium with several combinations of NAA and KIN, and moved to fresh medium after 60 days. Light did not interfere in embryo expression. Somatic embryos were formed either from individual cells or cell clusters. Plantlets were obtained in WPM medium and 10 gL -1 of sucrose with no plant regulator, or using 0.1 mgL -1 BAP and 0.5 mgL -1 GA. Plantlets from somatic embryos of D. morototoni developed in 33% of the cases.Keywords: somatic embryo, woody plants, embryogenesis, plantlets, Schefflera (Didymopanax), Araliaceae. RESUMO Regeneração in vitro de Didymopanax morototoniO presente estudo visou o estabelecimento de um completo protocolo de regeneração para Didymopanax morototoni (morototó, caixeta) uma espécie florestal nativa do Brasil. Quatro tipos de explantes (raiz, caule, nódulo foliar e folha cotiledonar) foram obtidos a partir de sementes germinadas. Na primeira etapa, meio WPM com caseína hidrolisada (250 mgL -1 ) e 2,4D (1,0 e 5,0 mgL -1 ) foram usados em combinação com cinetina (0,1 ou 1,0 mg L -1 ). Vinte dias depois de inoculado, o material foi avaliado. Calos embriogênicos foram divididos e transferidos para meio de expressão com várias combinações de ácido naftaleno-acético e cinetina, e repicados a cada 60 dias para meio novo. A luz não interferiu na expressão embriogênica. Embriões somáticos foram formados ou de células individuais ou de agregados de células. As plântulas foram obtidas no meio WPM com 10 g L -1 de sacarose e sem reguladores de crescimento ou com 0,1 mg L -1 de Benzil-adenina e 0,5 mg L -1 de giberelina. O desenvolvimento das plântulas a partir de embriões somáticos de D. morototoni foi alcançada em 33% dos casos.Palavras-chave: embrião somático, plantas lenhosas, embriogênese, Schefflera (Didymopanax), Araliaceae.

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“…The unicellular origins of somatic embryos was described (among others) in the leaf explant of Coffea arabica (Quiroz-Figueroa et al, 2002), coconut (Verdeil et al, 2001) and Dactylis glomerata (Trigiano et al, 1989). In some species, only the multicellular origins of somatic embryos were described, as, for example, in Carya illinoinensis (Rodriguez & Wetzstein, 1998) and Passiflora cincinnata (Rocha et al, 2011).…”

Section: Embryogenesis 310mentioning

confidence: 97%

“…The transition from the somatic to the embryogenic state requires the induction of embryogenic competence (Verdeil et al, 2001). How should one recognise this stage of SE?…”

Section: Changes In Cell Fate During Sementioning

confidence: 99%