oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 199 )

2018 ( 278 )

2017 ( 297 )

2016 ( 464 )

Custom range...

Search Results: 1 - 10 of 225624 matches for " Darcy Ríos "
All listed articles are free for downloading (OA Articles)
Page 1 /225624
Display every page Item
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.
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.
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
Photochemical Efficiency during the Establishment and Consolidation Phases of in Vitro Pinus radiata Micrograft Made from Scions of Different Ontogenetic Age  [PDF]
María E. Materán, Patricia L. Sáez, Manuel Sánchez-Olate, León A. Bravo, Roberto Rodríguez, Darcy Ríos, Rafael E. Coopman
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.61026
Abstract: The aim of the present study was to evaluate the applicability of maximal photochemical efficiency of photosystem II (Fv/Fm) as an early estimate of P. radiata micrografts viability coming from different position (basal vs. apical) in the ortets. We hypothesize that Fv/Fm variation is a good indicator of micrograft’s viability and phenological stage during micrograft development. The micrografts were established in QL medium supplemented whit 0.1 mg·L-1 IBA and 1 mg·L-1 BAP and cultured at 25°C ± 2°C and 80 μmol photons m-2s-1 of photosynthetic active radiation by 16 h per day. During the establishment and consolidation phase, we found significant differences in Fv/Fm with respect to time and buds positions provenience. During establishment, basal shoot tips have lower Fv/Fm than apical shoot tips, which agrees with the lowest viability (35%). However, during the consolidation phase, the trend changed and basal shoot tips presented higher Fv/Fm than apical shoot tips and showed an increase in ETR and NPQ, with respect to apical shoots and ortet. Although the measurement of fluorescence parameters implies the insertion of the fluorometer sonde in vitro, this implies aseptic considerations, but always conveies a contamination risk. We conclude that fluorescence (Fv/Fm, ETR, NPQ) can be indicators of the micrograft’s development according to the shoot tips position in the ortet and can be useful early-indicators of the scions’ physiological condition during micrograft transition from establishment to consolidation.
Changes in Gene Expression in Needles and Stems of Pinus radiata Rootstock Plants of Different Ontogenic Age  [PDF]
Carolina Alvarez, Luis Valledor, Patricia Sáez, Rodrigo Hasbún, Manuel Sánchez-Olate, María Jesús Ca?al, Darcy Ríos
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.78116
Abstract: A major problem in forest clonal productivity is the loss of morphogenetic capability with the increasing age of plants. However, despite of the importance of loss of morphogenetic competence, very little research has been done about the underlying mechanisms involved in this process. For this reason, a gene expression analysis using dot blot technique was performed in needles and stems of 1- and 3-year old Pinus radiata rootstock plants with a proved decrease in morphogenetic competence. Needles of one year old rootstock plants showed a higher number of up-regulated in genes mainly corresponding to photosynthesis and protein synthesis, degradation and modification, reflecting a higher number of active pathways in younger hedges, contrary to the older ones. Gene expression profiles found in stems are in agreement with those found in needles, indicating more active pathways in younger rootstock plants than in older ones. Several transcripts regulating transcription and translation were up-regulated in young competent tissues. Three-year-old stems presented an increase in the expression of an ethylene response factor, involved in plant organ senescence, indicating that pathways involved in senescence and ageing might inhibit the adventitious root formation, as in the older cuttings.
Variación de la Tasa de Enraizamiento Asociada al Número de Subcultivo y Diámetro de Microtallos de Casta o Castanea sativa Mill Rooting Rate Variation Related to Subculture Number and Diameter of Chestnut Castanea sativa Mill. Microshoots
Darcy Ríos L,Fabiola Avilés M,Manuel Sánchez-Olate,René Escobar R
Agricultura Técnica , 2005,
Abstract: Este estudio tuvo por objeto determinar el número de subcultivo y el diámetro basal en el cual se obtiene la mayor tasa de enraizamiento ex vitro para microtallos de casta o, Castanea sativa Mill., obtenidos vía cultivo in vitro. El material vegetal correspondió a microtallos provenientes del cultivo de embriones con entre 7 y 12 subcultivos durante la etapa de proliferación, para la cual se utilizó medio Driver y Kuniyuki Walnut (DKW) con los macronutrientes reducidos a la mitad y suplementado con 1 mg L-1 6-benzilaminopurina (BAP) y 0,1 mg L-1 de ácido indol 3-butírico (AIB). Se utilizó el método de inducción rápida de enraizamiento sumergiendo los tallos en una solución de 0,5 mg mL-1 de AIB durante 15 min. Para la etapa de enraizamiento, se utilizó como sustrato corteza de pino:perlita (4:1, v/v) evaluando los resultados a los 20 días de cultivo. Las variables evaluadas fueron tasa de supervivencia (%), tasa de enraizamiento (%), número de raíces, largo de raíces (mm), presencia de callo y aspecto del sistema radicular. Los resultados mostraron una disminución de la capacidad de enraizamiento a medida que aumenta el número de subcultivo. El factor diámetro de microtallo no presentó diferencias significativas respecto a las variables evaluadas. This study had the objective of determining the subculture number and the shoot basal diameter that produces the best rooting rate ex vitro of chestnut, Castanea sativa Mill., microshoots obtained via in vitro culturing. The plant material corresponded to microcuttings obtained from embryo cultures with between 7 and 12 subcultures in the proliferative stage, for which Driver and Kuniyuki Walnut (DKW) medium was used with the macronutrients reduced to a half and supplemented with 1 mg L-1 6-benzylaminopurine (BAP) and 0.1 mg L-1 indole-3-butiric acid (IBA). The quick induction rooting method was used, submerging the base of the microcuttings in a solution of 0.5 mg mL-1 of IBA for 15 min. For the rooting stage, pine bark:perlite (4:1, v/v) substrate was used, carrying out the evaluation of results at 20 days after culturing. The evaluated variables were survival rate (%), rooting rate (%), root number, root length (mm), callus presence and visual aspect of the rooting system. The results showed a decrease of rooting capacity as the subculture number increases. The factor microcutting diameter did not present significant differences with respect to the evaluated variables.
Encapsulated Somatic Embryos and Zygotic Embryos for Obtaining Artificial Seeds of Rauli-Beech (Nothofagus alpina (Poepp. & Endl.) Oerst.) Encapsulado de Embriones Somáticos y Embriones Cigóticos para Obtención de Semillas Artificiales de Raulí (Nothofagus alpina (Poepp. & Endl.) Oerst.)
Priscila Cartes R,Hermes Castellanos B,Darcy Ríos L,Katia Sáez C
Chilean Journal of Agricultural Research , 2009,
Abstract: Somatic and zygotic embryos from mature seeds of rauli-beech, Nothofagus alpina (Poepp. & Endl.) Oerst., were encapsulated in different artificial endosperms in order to generate a cover that fulfills the function of nourishment and protection of the embryos, facilitating their later germination. The content of sodium alginate varied by 4%, 3%, and 2%, as did the immersion time in calcium chloride (CaCl2), which acts as complexing agent. The artificial endosperm components of the Murashige and Skoog medium (MS) were added, supplemented with 0.5 mg L-1 indolacetic acid (IAA), 0.5 mg L-1 naphthaleneacetic acid (NAA), 2 mg L-1 6-benzylaminopurine (BAP) and 30 g L-1 sucrose. The germinative behaviors of encapsulated somatic and zygotic embryos were evaluated after 4 wk. Comparing the percentages of germination reached by encapsulated somatic and zygotic embryos it was observed that they had similar germinative behavior according to the type of encapsulation applied. However, zygotic embryos substantially exceeded the germination levels reached by somatic embryos, 100% vs. 45% respectively. Embriones somáticos y cigóticos provenientes de semillas maduras de raulí, Nothofagus alpina (Poepp. & Endl.) Oerst., se encapsularon en diferentes endospermas sintéticos con el fin de generar una cubierta que cumpla la función de nutrir y proteger al embrión para facilitar su posterior germinación. Se varió el contenido de alginato de sodio al 4%, 3% y 2% y el tiempo de inmersión en cloruro de calcio (CaCl2), el que actúa como agente acomplejante. Además, a la matriz artificial se adicionaron componentes del medio Murashige y Skoog (MS) suplementado con: 0,5 mg L-1 de indolacetic acid (IAA), 0,5 mg L-1 de ácido naftalenacético (NAA), 2 mg L-1 de 6-bencilaminopurina (BAP) y 30 gL-1 de sacarosa. Al cabo de 4 semanas el porcentaje de germinación de los embriones somáticos y cigóticos encapsulados tuvieron similar comportamiento germinativo según el tipo de encapsulado aplicado. Sin embargo, los embriones cigóticos superaron ampliamente los niveles de germinación alcanzados por los embriones somáticos, 100% vs. 45%, respectivamente.
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.
Page 1 /225624
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.