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Search Results: 1 - 10 of 373667 matches for " Darcy G. Ríos "
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Effect of Photon Flux Density and Exogenous Sucrose on the Photosynthetic Performance during In Vitro Culture of Castanea sativa  [PDF]
Patricia L. Sáez, León A. Bravo, Manuel Sánchez-Olate, Paulina B. Bravo, Darcy G. Ríos
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.714187
Abstract: The low photon flux density (PFD) under in vitro conditions and sucrose added to the culture medium negatively limits the photochemical activity and photoprotective mechanisms of microshoots. In this work we hypothesize that decreasing sucrose in the culture medium in combination with increasing irradiance, could improve the photosynthesis and consequently the in vitro growth. We evaluated the effect of exogenous sucrose (30 and 5 g·L-1, HS and LS, respectively), under different PFD (50 and 150 μmol photons m-2·s-1, LL and HL, respectively) on the photosynthetic performance and growth of Castanea sativa microshoots. Decreasing sucrose negatively affected the physiological attributes evaluated. Only chloroplast ultrastructure was improved by LS; however this did not lead to an improved in photosynthesis or growth. HL HS produced an increase in photosynthetic activity and chlorophyll contents, reaching under these conditions a higher proliferation rate and biomass production. Additionally, the photochemical activity (electron transport rate and non-photochemical quenching) was improved by HL. Thus, our results suggest that, at least for C. sativa HL is beneficial during the in vitro culture, improving photosynthetic performance as well as growth, but this is only possible in the presence of moderate concentrations of sucrose added to the culture medium.
Inducción de callo embriogénico en Eucalyptus globulus Labill
Gómez,Cristian; Matilde Uribe,Darcy Ríos; Sánchez-Olate,Manuel;
Interciencia , 2006,
Abstract: embryogenic callus induction starting from three explants coming from mature seeds (mature zygotic embryos, hypocotils and cotyledons) was studied. the results indicated that the medium i3 (b5 + ana 0.5mg·l-1 + bap 1.0mg·l-1) produced the largest percentages of callus formation in all the explants. micromorphology revealed the presence of embryogenic cells in all explants, while globular states in initial phases were found in hypocotils and cotyledons. later, in the differentiation phase, a maximum of 25 globular states by callus were obtained in a b5 medium with maltose (2% p/v) added, when using mature zygotic embryos. the histological study showed internal differentiation of globular states, characterized by a concentric formation of vascular bundles, parenchymatous cells towards the periphery and, finally, a protodermis formed by isodiametrical cells.
Inducción de caulogénesis indirecta en Eucalyptus globulus
Larson,Carmen Gloria; Gómez,Cristian; Sánchez-Olate,Manuel; Ríos,Darcy;
Bosque (Valdivia) , 2006, DOI: 10.4067/S0717-92002006000300004
Abstract: caulogenic induction was studied using mature seeds as initial explants. four concentrations of bap (0, 3, 5 and 7 mg l-1) in the mediums ms, b5 and sp were evaluated for the callus formation. the callus formed in the previous stage was used for the caulogenesis, evaluating the effect of two concentrations of ana (0.1 and 0.5 mg l-1), maintaining constant the bap (1.0 mg l-1) and the nutritious media from which they came. in the callus formation, the best results were obtained with 7 mg l-1 of bap (73%) when using the medium b5; differing significantly from ms. for the caulogenesis, the medium sp produced the highest values in formation of shoots (78%) differing significantly from the media b5 and ms. bap-ana？s combination (1.0-0.1 mg l-1) was more appropriate for the formation of shoots (62%), although without statistically differing from the other combination. in conclusion, the callus formation is directly related with the concentration of bap and the nutritious media used. also, the concentration of bap from which the callus and the combinations of bap and ana come, for the caulogenesis, do not influence significantly in the formation of adventitious shoots, contrary to the used nutritious media.
Efecto del subcultivo sucesivo sobre la caulogénesis adventicia de Eucalyptus globulus
Gómez,Cristian; Ríos,Darcy; Sánchez-Olate,Manuel;
Bosque (Valdivia) , 2007, DOI: 10.4067/S0717-92002007000100003
Abstract: the effect of successive subcultures on the microshoots production from organogenic lines of cigotic material of eucalyptus globulus was studied. nodal segments were subcultured every 50 days on proliferation medium (ms + 4.4 μm bap + 0.05 μm ana) and the microshoots per explant were counted. the results indicated a decrease in the quantity of microshoots from the 3rd to the 6th subculture (1.58 to 0.18 microshoots per explant), accompanied by a high density of mass proliferation. this effect was reverted by maintaining the mass proliferation in a free hormone ms medium for 30 days and later transferring it to a shoots proliferation medium. the proliferation index increased from 0.18, in the 6th subculture, and up to 1.03 shoots per explant in the7th subculture. the results indicated that maintaining the explants in cytokinins and auxins presence during successive subcultures induces a decrease in the caulogenic competition and consequently, a smaller microshoots production. transferring the explants to free hormones medium helps to recover the lost or diminished competition, allowing an increase in the microshoots production with exogenous cytokinins and auxins.
Inducción de caulogénesis indirecta en Eucalyptus globulus Induction of indirect caulogenesis in Eucalyptus globulus
Carmen Gloria Larson,Cristian Gómez,Manuel Sánchez-Olate,Darcy Ríos
Bosque (Valdivia) , 2006,
Abstract: Se estudió la inducción caulogénica utilizando semillas maduras como explantos iniciales. Para la callogénesis se evaluaron cuatro concentraciones de BAP (0, 3, 5 y 7 mg L-1) en los medios MS, B5 y SP. Para la caulogénesis se utilizaron los callos formados en la etapa anterior, evaluando el efecto de dos concentraciones de ANA (0,1 y 0,5 mg L-1), manteniendo constante el BAP (1,0 mg L-1) y el medio nutritivo del cual provenían. En la callogénesis los mejores resultados se obtuvieron con 7 mg L-1 de BAP (73%) al utilizar el medio B5, difiriendo significativamente de MS. Para la caulogénesis, con el medio SP se obtuvieron los valores más altos de formación de brotes (78%) difiriendo significativamente de los medios B5 y MS. La combinación de BAP-ANA (1,0-0,1 mg L-1) resultó más apropiada para la formación de brotes (62%), aunque sin diferir estadísticamente de la otra combinación. Se concluye que la callogénesis está directamente relacionada con la concentración de BAP y el medio nutritivo utilizado. Además, la concentración de BAP del cual provienen los callos y las combinaciones de BAP y ANA para la caulogénesis, no influyen significativamente en la formación de brotes adventicios, a diferencia del medio nutritivo utilizado. Caulogenic induction was studied using mature seeds as initial explants. Four concentrations of BAP (0, 3, 5 and 7 mg L-1) in the mediums MS, B5 and SP were evaluated for the callus formation. The callus formed in the previous stage was used for the caulogenesis, evaluating the effect of two concentrations of ANA (0.1 and 0.5 mg L-1), maintaining constant the BAP (1.0 mg L-1) and the nutritious media from which they came. In the callus formation, the best results were obtained with 7 mg L-1 of BAP (73%) when using the medium B5; differing significantly from MS. For the caulogenesis, the medium SP produced the highest values in formation of shoots (78%) differing significantly from the media B5 and MS. BAP-ANA’s combination (1.0-0.1 mg L-1) was more appropriate for the formation of shoots (62%), although without statistically differing from the other combination. In conclusion, the callus formation is directly related with the concentration of BAP and the nutritious media used. Also, the concentration of BAP from which the callus and the combinations of BAP and ANA come, for the caulogenesis, do not influence significantly in the formation of adventitious shoots, contrary to the used nutritious media.
Efecto del subcultivo sucesivo sobre la caulogénesis adventicia de Eucalyptus globulus Effect of successive subculture on adventitious caulogenesis of Eucalyptus globulus
Cristian Gómez,Darcy Ríos,Manuel Sánchez-Olate
Bosque (Valdivia) , 2007,
Abstract: Se estudió el efecto de subcultivos sucesivos sobre la producción de microtallos desde líneas organogénicas de material cigótico de Eucalyptus globulus. Cada 50 días fueron subcultivados segmentos nodales en medio de proliferación (MS + 4,4 μM BAP + 0,05 μM ANA) y se contabilizó el número de microtallos por explanto. Los resultados indicaron una disminución en la cantidadde microtallos desde el 3o al 6o subcultivo (de 1,58 a 0,18 microtallos por explanto), que fue acompa ada por una compactación general de los macizos de proliferación. Este efecto se revirtió manteniendo los macizos en un medio MS libre de hormonas por 30 días y posterior transferencia a medios de proliferación de brotes, con lo cual el índice de proliferación aumentó desde 0,18, en el 6o subcultivo, hasta 1,03 brotes por explanto en el 7o subcultivo. Los resultados indicaron que mantener los explantos durante subcultivos sucesivos en presencia de citoquininas y auxinas induce una disminución en la competencia caulogénica y por consiguiente, una menor producción de microtallos. El repicar el material a un medio libre de hormonas ayuda a recuperar la competencia perdida o disminuida, permitiendo el aumento en la producción de microtallos con citoquininas y auxinas exógenas. The effect of successive subcultures on the microshoots production from organogenic lines of cigotic material of Eucalyptus globulus was studied. Nodal segments were subcultured every 50 days on proliferation medium (MS + 4.4 μM BAP + 0.05 μM ANA) and the microshoots per explant were counted. The results indicated a decrease in the quantity of microshoots from the 3rd to the 6th subculture (1.58 to 0.18 microshoots per explant), accompanied by a high density of mass proliferation. This effect was reverted by maintaining the mass proliferation in a free hormone MS medium for 30 days and later transferring it to a shoots proliferation medium. The proliferation index increased from 0.18, in the 6th subculture, and up to 1.03 shoots per explant in the7th subculture. The results indicated that maintaining the explants in cytokinins and auxins presence during successive subcultures induces a decrease in the caulogenic competition and consequently, a smaller microshoots production. Transferring the explants to free hormones medium helps to recover the lost or diminished competition, allowing an increase in the microshoots production with exogenous cytokinins and auxins.
Proteomic Analysis through Adventitious Rooting of Pinus radiata Stem Cuttings with Different Rooting Capabilities  [PDF]
Carolina álvarez, Luis Valledor, Patricia Sáez, Manuel Sánchez-Olate, Darcy Ríos
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.714174
Abstract: In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata. However, the capability of produce adventitious roots in gymnosperms decreases with aging. While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level. This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities. Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process. It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting. According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively. Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.
Biomass partitioning and leaf area of Pinus radiata trees subjected to silvopastoral and conventional forestry in the VI region, Chile
RODRíGUEZ,ROLANDO; HOFMANN,GLENN; ESPINOSA,MIGUEL; RíOS,DARCY;
Revista chilena de historia natural , 2003, DOI: 10.4067/S0716-078X2003000300008
Abstract: the effects of silvicultural regimes on leaf area and biomass distribution were analyzed in 16-year old pinus radiata trees growing in the semiarid zone of chile. three stands with different silvopastoral management were compared with a conventionally managed stand. data were obtained through destructive sampling of 36 trees and analyzed by manova and regression models of ancova. results show that the management regime affects the leaf area. specific leaf area was affected by both silvicultural regime and crown position. total biomass per tree under the silvopastoral regime was 2.1 to 2.5 times larger than in the conventional forestry regime. however, aboveground biomass partitioning was neither affected by the silvicultural regime nor by the schemes of silvopastoral management. the most important allometric change was in fine root biomass, which was greater under the conventional forestry regime than in the silvopastoral one. fine root biomass increases with a regular distribution of the plants in the field, and decreases with the clumping of trees. similarly, the fine root biomass decreases with fertilization. both plantation design and fertilization regimes explain the changes in the fine root biomass to components of the crown. however, crown structure influences the magnitude of these changes.
Biomass partitioning and leaf area of Pinus radiata trees subjected to silvopastoral and conventional forestry in the VI region, Chile Distribución de biomasa y área foliar en árboles de Pinus radiata sometidos a manejo silvopastoral y convencional en la VI región, Chile
ROLANDO RODRíGUEZ,GLENN HOFMANN,MIGUEL ESPINOSA,DARCY RíOS
Revista chilena de historia natural , 2003,
Abstract: The effects of silvicultural regimes on leaf area and biomass distribution were analyzed in 16-year old Pinus radiata trees growing in the semiarid zone of Chile. Three stands with different silvopastoral management were compared with a conventionally managed stand. Data were obtained through destructive sampling of 36 trees and analyzed by MANOVA and regression models of ANCOVA. Results show that the management regime affects the leaf area. Specific leaf area was affected by both silvicultural regime and crown position. Total biomass per tree under the silvopastoral regime was 2.1 to 2.5 times larger than in the conventional forestry regime. However, aboveground biomass partitioning was neither affected by the silvicultural regime nor by the schemes of silvopastoral management. The most important allometric change was in fine root biomass, which was greater under the conventional forestry regime than in the silvopastoral one. Fine root biomass increases with a regular distribution of the plants in the field, and decreases with the clumping of trees. Similarly, the fine root biomass decreases with fertilization. Both plantation design and fertilization regimes explain the changes in the fine root biomass to components of the crown. However, crown structure influences the magnitude of these changes. Se analizaron los efectos del régimen silvícola en el área foliar y distribución de biomasa en árboles de Pinus radiata de 16 a os, creciendo en la zona semiárida de Chile. Para ello se compararon tres rodales con manejo silvopastoral con uno manejado en forma tradicional. Los datos se obtuvieron mediante muestreo destructivo de 36 árboles y se analizaron mediante MANOVA y regresión en modelos de ANCOVA. Los resultados permiten concluir que el régimen de manejo afectó el área foliar. El área foliar específica fue afectada por el régimen silvícola y su posición en la copa. La biomasa total por árbol con régimen silvopastoral es 2,1 a 2,5 veces mayor que los árboles con régimen solo forestal. Sin embargo, la distribución de la biomasa aérea no fue afectada por el régimen silvícola ni por los diferentes manejos silvopastorales. El cambio alométrico más importante fue en la biomasa de raíces finas, la que fue mayor en el régimen de manejo forestal tradicional que el silvopastoral. La relación significativa entre biomasa de raíces finas y componentes de la copa concuerda con el modelo de balance funcional y aumenta cuando la distribución de las plantas es uniforme. La biomasa de raíces finas decrece con la fertilización. Ambos factores explican los cambios de biom
Potencial de la organogénesis como estrategia para la masificación in vitro de Persea lingue en la zona centro-sur de Chile Potential of organogenesis as a strategy to the in vitro propagation of Persea lingue in the south-central region of Chile
José Cob,Ana M Sabja,Darcy Ríos,Antonio Lara
Bosque (Valdivia) , 2010,
Abstract: Persea lingue (lingue) es una especie arbórea nativa de Chile apta para producir madera de alta calidad y belleza. El presente estudio evaluó el efecto de componentes hormonales suplementado con medios de cultivo sobre la capacidad morfogénica de Persea lingue y se analizó el proceso de regeneración in vitro mediante estudios histológicos. Se ensayó el medio de cultivo básico Murashige y Skoog (MS) complementado con diferentes concentraciones de ácido indol 3-butírico (AIB) y 6-bencilaminopurina (BAP), usando secciones apicales de microtallos obtenidos de embriones maduros germinados in vitro. Se utilizó un dise o en bloques completos aleatorizados con cinco repeticiones y arreglo factorial de tratamientos; la unidad experimental fue un recipiente de cultivo conteniendo un explante. Hubo efectos significativos (P = 0,001) del tratamiento sobre las variables respuesta número de yemas, número de brotes y elongación caulinar. La prueba de rangos múltiples de Duncan confirmó que los tratamientos que observaron diferencias significativas fueron 0,1 mg L-1 de AIB y 2,0 mg L-1 de BAP para la inducción de yemas por explante y 0,05 mg L-1 de AIB y 0,5 mg L-1 de BAP para la elongación caulinar. El análisis histológico demostró que la proliferación de células meristemáticas se inició a partir del tejido epidérmico y subepidérmico. Asimismo, corroboró el proceso de regeneración in vitro vía organogénesis directa. Estos resultados ratifican a la organogénesis como una potencial herramienta biotecnológica útil para rescatar, conservar y propagar masivamente a esta especie nativa. Lingue (Persea lingue) is a native arboreal species of Chile, adequate for producing high quality wood and also recognized for its beauty. The effect of supplemented hormonal components in the culture medium of the Persea lingue were studied, morphogenetic capacity and the in vitro regeneration process via histological studies were analyzed. The Murashige and Skoog (MS) basic culture medium was used and complemented with different concentrations of indole 3-butyric acid (IBA) and 6- Benzylaminopurine (BAP) using apical sections of microshoots obtained from in vitro germinated mature embryos. A complete random block design was applied with five repetitions and factorial arrangement of treatments, the experimental unit was a culture recipient containing one explant. The variance analysis showed statistically significant differences (P = 0.001) of the treatment factor on the above response, variable number of buds per explant and caulinary elongation. Regarding Duncan’s multiple range test, it
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