A novel approach for the definition of the inorganic medium components for micropropagation of yellow passionfruit (Passiflora edulis sims. F. Flavicarpa Deg.)

Abstract

Mineral deficiency symptoms were observed in leaves of yellow passionfruit plantlets grown in MS medium (Murashige and Skoog, 1962) with 1.0 mg l 21 (3.0 mM) gibberellic acid. Initially, leaves showed interveinal chlorosis, followed by bleaching of the leaves and retarded growth. Leaf mineral analysis was done and compared to mineral requirements suggested for passionfruit in the literature. Several modifications were made to the inorganic composition of MS medium, according to mineral deficiencies, mainly of Fe and Ca, and possible toxicity of Cl. The concentration of the elements in the new medium (MSM) was based on the mineral composition of leaves of healthy plants. The chemical equilibrium was checked using the software Geochem (Sposito and Mattigod, 1980) and final adjustments were made to ensure good availability of nutrients. To test the efficiency of the modified medium nodal segments were cultured in both MS and MSM supplemented with 3.0 mg l 21 (13.3 mM) 6-benzyladenine. After three subcultures mineral analysis of the leaves was done. Severe mineral deficiency was observed on the leaves of plantlets cultured in MS, while plantlets cultivated in MSM had green leaves. A comparison of the mineral analysis of plantlets in both media showed a fairly large increase in Ca, Cu, Fe, Mg and S and decrease in levels of B and Cl in plantlets cultivated in MSM. A slight increase or decrease in other elements was also observed. Subculture of the chlorotic plantlets into MSM showed that the visual symptoms of mineral deficiency disappeared in 2±4 wk.

Microenxertia ex vitro para eliminação do vírus CABMV em maracujá-azedo

“…A ausência de efeito dos meios de cultura pode ser atribuída à falta de competência dos tecidos do hipocótilo para a reação aos estímulos proporcionados, o que é dependente da condição morfo-fisiológica das plântulas (Drew, 1991;Taiz & Zeiger, 2004). Embora estudos sobre a cultura de tecidos jovens, em espécies do gênero Passiflora, tenham demonstrado a resposta ao fitorregulador BAP (Biasi et al, 2000;Monteiro et al, 2000), ele não foi eficiente na indução da organogênese a partir de tecidos adultos de P. edulis f. edulis (Biricolti & Chiari, 1994). Em estudos sobre a microenxertia em citros, Navarro et al (1975) não encontraram efeito significativo da aplicação de AIB e BAP sobre o porta-enxerto, antes da implantação do ápice.…”

“…Os tratamentos foram constituídos por: ausência de aplicação de meios de cultura (controle); sais MS (Murashige & Skoog, 1962), adicionados com 3% de sacarose, 10 mg L -1 de tiamina, 1 mg L -1 de piridoxina, 1 mg L -1 de ácido nicotínico, 100 mg L -1 de mio-inositol, 2 g L -1 de Phytagel, com pH ajustado para 5,8 (daqui em diante referido como meio MS); meio MS acrescido de 0,1 mg L -1 de AIB; meio MS acrescido de 2 mg L -1 de BAP; meio MS acrescido de 0,1 mg L -1 de AIB e 1 mg L -1 de BAP; meio MS acrescido de 0,2 mg L -1 de AIB e 2 mg L -1 de BAP. Os meios de cultura utilizados como adjuvantes foram preparados conforme recomendações de Torres et al (2001) e autoclavados a 121ºC por 20 min.…”

“…A cultura do maracujá-azedo (Passiflora edulis Sims f. flavicarpa Degener) tem sido prejudicada pela doença do endurecimento dos frutos, causada principalmente pelo Cowpea aphid-borne mosaic virus (CABMV), doença de etiologia viral mais importante no Brasil e que está disseminada na maioria das regiões produtoras (Nascimento et al, 2006). Essa enfermidade causa diminuição e deformação dos frutos e está associada à ocorrência de bolsas de goma no albedo.…”

Optimization of in vitro organogenesis in passion fruit (Passiflora edulis f. flavicarpa)

“…Shoots obtained from leaf discs cultured on MS medium supplemented with 1.1 µmol L -1 TDZ + 23.5 µmol L -1 AgNO 3 were transferred for elongation to Magenta GA7 boxes (Sigma) containing one of the following culture media: MSM (Monteiro et al, 2000) supplemented with 2.6 µmol L -1 GA 3 ; MSM supplemented with coconut water (10%); or ½ MSM salts, in a completely randomized experimental design (n = 5), each replication consisting of one Magenta GA7 box with five explants. Flasks were capped with normal or vented lids (Sigma).…”

“…f. flavicarpa Deg.) has been obtained from shoot apices or nodal segments cultivation (Drew, 1991;Faria & Segura, 1997a;Monteiro et al, 2000;Reis et al, 2003) or from adventitious buds developed from leaf discs (Dornelas & Vieira, 1994;Appezzato-da-Glória et al, 1999), hypocotyl (Faria & Segura, 1997b), or internodal segments (Biasi et al, 2000). Optimized protocols have been established mainly by using different combinations of plant growth regulators, such as BAP and IBA (Kawata et al, 1995), BAP and NAA (Dornelas & Vieira, 1994), BAP and IAA (Faria & Segura, 1997b), and different salt solutions (Faria & Segura, 1997b;Monteiro et al, 2000).…”