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Efectos de la radiación solar sobre los patrones de la regeneración, en un bosque sobremaduro de Nothofagus dombeyi (Mirb.) Oerst. localizado en el centro-sur de los Andes, Chile ABSTRACT Nothofagus species behave like early successional species that recolonize open sites after of regular and large-scale disturbances. This study analyzed the effects of light regimes on patterns of advanced regeneration dynamics, growth in diameter and height of Nothofagus dombeyi (Mirb.) Oerst. (Density of 240 trees ha -1 , basal area of 56.7 m 2 ha -1 ). Systematic sampling every 50 m in three stands (7.5 ha) was used. At each point and with the same center, two concentric circular plots were established, 9.0 m and 1.8 m radius. For estimate solar radiation transmissivity in plots, a solariscope hemispheric photographic camera was used. Diameters at breast height and basal areas (BA), heights (H) were measured and then counted and measured N. dombeyi seedlings and saplings. 13 saplings of advanced regeneration were harvested from all gaps to obtain age (E), total height (TH), absolute radial growth (ARG), and absolute height growth (AHG). As results, solar radiation varied between 3 and 40%. ARG varied between 1.20 and 2.22 mm yr -1 and AHG between 0.15 and 0.43 m yr -1 . We found correlation for ARG and AHG with direct and global solar radiation transmissivity, but not with diffuse solar radiation transmissivity. The plant age and transmittance of direct and global solar radiation explains the increases in diameter and height. However, in our study stated that in the Andean region of south-central Chile, N. dombeyi stands is affected by small-scale disturbances. Therefore, transmissivity radiation solar inside the forest, explaining natural regeneration patterns and growth of N. dombeyi. RESUMENLas especies de Nothofagus se comportan como especies sucesionales tempranas que recolonizan sitios abiertos después de disturbios regulares y de gran escala. Este estudio analizó los efectos de los regímenes de luz, en los patrones de dinámica de regeneración avanzada, crecimiento en diámetro y altura de Nothofagus dombeyi (Mirb.) Oerst. (Densidad de 240 árboles ha -1 , área basal de 56,7 m 2 ha -1 ). Se utilizó un muestreo sistemático cada 50 m en tres rodales (7,5 ha). En cada punto y con el mismo centro se establecieron dos parcelas circulares, 9,0 m y 1,8 m de radio. Se midió la transmisividad de la radiación solar con una cámara fotográfica hemisférica solariscope. Se midieron los diámetros a la altura del pecho, áreas basales (BA), alturas (H) y se contaron las plántulas y plantas de N. dombeyi. En los claros se cosecharon 13 plantas de la regeneración avanzada, para obtener la edad (E), la altura total (TH), el crecimiento radial absoluto (ARG) y el crecimiento absoluto en altura (AHG). La radiación solar varió entre 3 y 40%. ARG varió entre 1,20 y 2,22 mm año -1 y AHG entre 0,15 y 0,43 m año -1 . Se encontró correlación para ARG y AHG con transmisividad de radiación solar directa y global, pero no con transmisividad de radiación...

Abscisic acid (ABA) and indole-3-acetic acid (IAA) participate in the propagation of plants by somatic embryogenesis, causing polar structural differentiation of the embryo. The goal of the assay was to compare endogenous levels of ABA and IAA between somatic embryos (SE) and zygotic embryos (ZE) of Nothofagus alpina (Poepp. & Endl.) Oerst. In this study, a somatic embryo maturation assay involving the addition of varying concentrations of exogenous ABA was performed on cotyledonary-stage of N. alpina. Furthermore, the endogenous levels of ABA and IAA were quantified in the immature ZE, the mature ZE, and the embryonic axis of a mature embryo of N. alpina. The current study utilized high performance liquid chromatography (HPLC) for quantification. The maturation treatments performed did not present significant differences in the endogenous ABA levels in SE. However, significant differences did exist in levels of ABA and IAA between SE submitted to the different maturation treatments and mature ZE of N. alpina. The application of exogenous ABA to the culture medium increased endogenous ABA levels, therefore, increasing the number of germinated somatic embryos. Thus, the plant conversion process was also successfully completed in somatic embryos of N. alpina.

Competencia morfogénica de embriones maduros de Pinus radiata cultivados in vitro y su relación con la posición del cono en el árbol Morphogenic competence of mature in vitro cultured Pinus radiata embryos and their relation with cone position in the tree