Somatic Embryogenesis: Factors Influencing Coordinated Behaviour of Cells as an Embryogenic Group

Williams, Elizabeth; Maheswaran, G.

doi:10.1093/oxfordjournals.aob.a087127

Cited by 519 publications

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“…Somatic embryogenesis is an in vitro morphogenic response in which embryos are induced from somatic cells, with further Polyploidy and sterility, characteristics of commercial cultivars of Musa spp., are disadvantageous for the inclusion of banana Autor para correspondência: adriana@cena.usp regeneration of plants (Williams & Maheswaran 1986). In general, the process follows three main stages: induction of embryogenic callus, development and maturation of somatic embryos, and conversion of somatic embryos into plants.…”

Section: Introductionmentioning

confidence: 99%

Histological changes in banana explants, cv. Nanicão (Musa spp., Group AAA), submitted to different auxins for induction of somatic embryogenesis

Filippi

Appezzato‐da‐Glória

2001

Rev. bras. Bot.

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-(Histological changes in banana explants, cv. Nanicão (Musa spp. Group AAA), submitted to different auxins for induction of somatic embryogenesis). The present work analyzes the behavior of banana explants, cv. Nanicão (Musa spp. Group AAA) regarding somatic embryogenesis induction treatments with several auxins. Longitudinal segments of shoot meristematic apices of micropropagated banana plantlets cultivated and rooted in vitro were introduced in culture medium containing dicamba, picloram, 2,4-D or NAA in different concentrations. Explant samples were collected at 0, 7 and 10 days and prepared for light microscopy. Histological sections were used for comparison of the histological changes occurring after induction treatment with different auxins. Embryogenic response was observed only in treatments with picloram or dicamba, with distinct embryogenic regions observed at 14 and 21 days in culture, respectively. Histological sections of embryogenic regions of the explant at 26 days in culture revealed the formation of meristematic regions, structures with multiple root meristems, and somatic embryos at early globular stages. Embryo-like structures morphologically similar to Musa balbisiana zygotic embryos were sectioned and showed a lack of apical meristems and absence of procambial differentiation. These results indicate the induction of non-functional somatic embryos and the need for more studies on developmental aspects and maturation treatments for optimization of the process.RESUMO -(Alterações histológicas em explantes de bananeira, cv. Nanicão (Musa spp. Grupo AAA) submetidos a diferentes auxinas para indução de embriogênese somática). O presente trabalho analisa o comportamento de explantes de bananeira 'Nanicão' (Musa spp. Grupo AAA) a tratamentos de indução com diferentes auxinas, visando à obtenção de embriogênese somática. Segmentos longitudinais de ápices meristemáticos caulinares de plântulas de bananeira micropropagadas e enraizadas in vitro foram introduzidos em meio de cultura contendo dicamba, picloram, 2,4-D ou NAA. Amostras dos explantes aos 0, 7 e 10 dias foram coletadas e preparadas para microscopia óptica. Cortes histológicos foram realizados nesses explantes, comparando-se as alterações observadas após os tratamentos com diferentes auxinas. Respostas embriogênicas foram observadas somente nos tratamentos com picloram e dicamba, sendo possível a observação visual de regiões embriogênicas aos 14 e 21 dias de cultivo, respectivamente. Cortes histológicos de regiões embriogênicas dos explantes, aos 26 dias, revelaram a formação de regiões meristemáticas compostas aparentemente por múltiplos meristemas radiculares e embriões nas fases iniciais do estágio globular. Cortes histológicos de estruturas morfologicamente semelhantes a embriões zigóticos de Musa balbisiana revelaram ausência dos meristemas apicais e não diferenciação procambial. Os resultados indicam a indução de embriões somáticos não-funcionais e, consequentemente, a necessidade de maiores estudos visando otimizar o process...

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Section: Introductionmentioning

confidence: 99%

Histological changes in banana explants, cv. Nanicão (Musa spp., Group AAA), submitted to different auxins for induction of somatic embryogenesis

Filippi

Appezzato‐da‐Glória

2001

Rev. bras. Bot.

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“…Porém, resultados obtidos com 1 mg.L -1 de 2,4-D na ausência da citocinina foram bastante satisfatórios, atingindo freqüência de 33% de CE s. Berthouly & Michaux-Fierrere (1996), estudando genótipos de C. canephora, observaram que a adição de BAP em concentrações acima de 1,5 M favorece mais a diferenciação de células embriogênicas em relação a sua multiplicação, provavelmente por alterar a polaridade e o plano de divisão da célula (Williams & Maheswaran, 1986).…”

Section: Porcentual De Calos Embriogênicosunclassified

“…A embriogênese somática indireta requer a determinação de células diferenciadas, a proliferação de calos e a indução de células embriogênicas determinadas, dependendo da ação de reguladores de crescimento, não apenas para a retomada da atividade mitótica, mas também para a determinação do estado embriogênico (Sondahl et al, 1985;Williams & Maheswaran, 1986). Contudo, duas estratégias têm sido utilizadas com o objetivo de obtenção de tecido embriogênico em Coffea: a primeira envolve o cultivo de explante sobre um único meio de cultura, suplementado apenas com citocinina (Yasuda et al, 1995), ou a combinação de auxina e citocinina (Pierson et al, 1983); a segunda estratégia utiliza o cultivo de explantes em um meio primário ou de indução, seguido da transferência dos explantes para o meio secundário, tido como de diferenciação (Dublin, 1984) ou de acondicionamento, que difere do primeiro por possuir menor razão auxina/citocinina (Noriega & Sondahl, 1993;Sondahl et al, 1985;Zamarripa et al, 1991).…”

Section: Introductionunclassified

Embriogênese somática indireta em explantes foliares de Coffea arabica L. CV. Obatã

Maciel¹,

Pasqual²,

Pereira³

et al. 2003

Ciênc. agrotec.

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INDIRECT SOMATIC EMBRYOGENESIS INCoffea arabica L. CV. OBATÃ 1 ABSTRACT It was aimed with this work to study the indirect somatic embryogenesis in Coffea arabica L. cv. 'Obatã', including the steps of induction, differentiation and regeneration of plants. Leaf segments withdrawn from plants under field conditions were disinfected with 70% alcohol for 1 , 1% sodium hypochlorite for 15 and inoculated in 'CI' medium (callus induction) supplemented with 2,4 D (0, 1, 2 and 4 mg.L -1 ) and kinetin (0, 2, 4 and 8 mg.L -1 ). Later, the callus were transferred to the 'CD' medium (callus differentiation) to which was added 2,4-D (0, 1, 2 and 4 mg.L -1 ) and BAP (0, 2, 4 and 8 mg.L -1 ). During the regeneration step, friable embryogenic callus were inoculated in 'R' medium supplemented with BAP (0, 2, 4 and 6 mg.L -1 ) and sucrose (0, 15, 30, 45 and 60 g.L -1 ). The culture media utilized had their pH adjusted to 5.6 ± 1 before being autoclaved. The experiments were kept in growth room at 26 ± 1 o C. Over the steps of callus 1. Parte da Dissertação apresentada pelo primeiro autor à UNIVERSIDADE FEDERAL DE LAVRAS/UFLA, Caixa Postal 37 37200-000 LAVRAS, MG, como parte das exigências do curso de Mestrado em Agronomia, área de concentração Fitotecnia.

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“…Somatic embryogenesis involves control of 3 consecutive steps: (i) induction of embryogenic lines from sporophytic cells; (ii) maintenance and multiplication of embryogenic lines; (iii) maturation of somatic embryos and conversion into viable plantlets [47].…”

Section: Introductionmentioning

confidence: 99%

“…In angiosperm species, multiplication of embryogenic lines can be achieved either by regular subculturing of explants taken from compact or friable embryogenic calli [43], or by formation of new embryos from the previously developed somatic embryos themselves [3,42,46,47]. This second case is referred to as secondary embryogenesis.…”

Section: Introductionmentioning

confidence: 99%

Histological investigation of the multiplication step in secondary somatic embryogenesis of Quercus robur L.

2001

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-Standardized explants composed of hypocotyl and root-tip were prepared from embryonic structures obtained from one embryogenic line of Quercus robur L. maintained by regular transfer onto a solidified reference medium composed of the MS mineral solutions, glucose (0.12 M), casamino acid (0.1%), and NAA (10.74 µM). The regeneration capacity from these explants were tested on the reference medium and on 2 alternative media in which the NAA (10.74 µM) was omitted or substituted for a combination of IBA (9.80 µM)/BAP (8.90 µM). Within 30 days, 4 types of responses were observed including direct and indirect secondary embryogenesis. In the direct pathway, somatic embryos arose from 3-4 epidermal cells following two different modes, depending on whether or not the formation of a meristematic mass preceded the initiation of the embryogenic process. In the indirect pathway the embryos were formed from clumps of mitotically active cells included in callus developed within the cortical tissues. Depending on their histological origin, the embryos exhibited differences in their structural organization which could influence their potential for further maturation and conversion into viable plantlets. Explants prepared from small translucent embryonic structures were more embryogenic and expressed the direct pathway of secondary embryogenesis at higher frequency than explants prepared from more advanced embryonic structures. On the culture medium without growth regulator, direct secondary embryogenesis was the exclusive response whereas on the culture medium with growth regulators added both direct and indirect secondary embryogenesis occurred. NAA favoured the direct secondary embryogenesis, while conversely, the IBA/BAP combination stimulated the indirect secondary embryogenesis. The results are discussed in reference to the PEDC concept (pre-embryogenic determined cells).

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Somatic Embryogenesis: Factors Influencing Coordinated Behaviour of Cells as an Embryogenic Group

Cited by 519 publications

References 0 publications

Histological changes in banana explants, cv. Nanicão (Musa spp., Group AAA), submitted to different auxins for induction of somatic embryogenesis

Histological changes in banana explants, cv. Nanicão (Musa spp., Group AAA), submitted to different auxins for induction of somatic embryogenesis

Embriogênese somática indireta em explantes foliares de Coffea arabica L. CV. Obatã

Histological investigation of the multiplication step in secondary somatic embryogenesis of Quercus robur L.

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