Crecimiento anual de cuatro especies arbóreas con yemas desnudas nativas de los bosques templados húmedos de Patagonia.

Abstract

Summary: Annual growth of four naked-bud tree species from the temperate rainforests of Patagonia. Plant species inhabiting regions with low seasonality in climate tend to exhibit some morpho-architectural features that occur less frequently in species from regions with seasonal climate. This study was aimed at evaluating the primary growth of nursery-grown trees of four woody species native to the temperate rainforests of Patagonia, also known as Valdivian rainforests, where the degree of seasonality is lower than in other Patagonian forests. The selected species, Aextoxicon punctatum, Luma apiculata, Myrceugenia exsucca and Sophora microphylla, have naked buds, like many tropical species. Fenology, growth and branching of the main axis of marked plants were evaluated during one calendar year. Primary growth was markedly seasonal in all four species, as previously recorded for coexisting tree species with scaly buds. However, notable intra-and inter-specific differences in the onset and completion of growth were detected; L. apiculata and M. exsucca (Myrtaceae) exhibited higher intra-specific variations than the other two species. Our results indicate that several factors would be involved in regulating primary growth in these species, something found in species with continuous growth.Key words: Architecture, Aextoxicon punctatum, Luma apiculata, Myrceugenia exsucca, primary growth, Sophora microphylla, Valdivian rainforest.Resumen: Las especies vegetales que habitan en regiones con bajo nivel de estacionalidad en el clima suelen presentar rasgos morfo-arquitecturales que ocurren con menor frecuencia en especies de regiones con clima estacional. El objetivo de este estudio fue evaluar el crecimiento primario en vivero de cuatro especies leñosas típicas de los bosques templados húmedos de Patagonia, conocidos como selva valdiviana, donde el grado de estacionalidad es menos marcado que en otros bosques patagónicos. Las especies estudiadas, Aextoxicon punctatum, Luma apiculata, Myrceugenia exsucca y Sophora microphylla, comparten con muchas especies tropicales la posesión de yemas desnudas. Se evaluaron, durante un año calendario, la fenología, el crecimiento y la ramificación del eje principal de plantas marcadas. El crecimiento primario en estas especies fue marcadamente estacional, como en se ha registrado en especies arbóreas con yemas escamosas con las que coexisten. Sin embargo, se detectaron notables diferencias intra-e inter-específicas en el inicio y la finalización del crecimiento; L. apiculata y M. exsucca (Myrtaceae) presentaron mayores variaciones que las restantes dos especies. Nuestros resultados indican la intervención de varios factores reguladores del crecimiento primario en las especies estudiadas, como ocurre en especies con crecimiento continuo.

The dynamics of primary growth in woody species from rain and transitional forests of Argentinean north Patagonia

“…This is not the case of the present study, although we observed plants in similar ontogenetic stages and under non-limiting water conditions; that means extension durations recorded for rainforest species were higher (up to 15 weeks) than those for transitional forest species. For rainforest species, our results are similar to those reported for other Patagonian rainforest species in a recent common-garden study (Sosa and Puntieri 2016). Consequently, preliminarily, these results are in accordance with our initial hypothesis.…”

Naked resting bud morphologies and their taxonomic and geographic distributions in temperate, woody floras

“…An alternative version of the nonadaptive argument is that the temperate zone as a whole should be thought of as having a winter climate inhospitable to exposed naked bud survival, but due to heterogeneity, certain specific subclimates or microclimates may still accommodate species with naked buds. Examples of specific subclimates that might be more suitable to species with naked buds occur in the treatment of Viburnum species in Europe (Kollmann & Grubb, 2002) and in the descriptions of naked‐budded species that occur in the temperate rainforests of Patagonia (Magnin et al ., 2012; Sosa & Puntieri, 2016). In a study on an evergreen broadleaved forest locale in central Japan, Nitta & Ohsawa (1998) argued that bud type could be associated with stratification in a temperate forest environment as the crowns of canopy trees are more exposed to temperature fluctuations and disturbances than the branches of the species that inhabit the shrub layer or understory (Kikuzawa & Lechowicz, 2011).…”

“…Consequently, temperate, woody species with naked buds that lack cataphylls are often represented as rare or remarkable occurrences. Some of the hypotheses that have been put forward to explain the counterintuitive existence of naked buds outside of the wet tropics, for example, seek to identify temperate species with naked buds as anomalies restricted to mild subclimates or sheltered understory environments (Nitta & Ohsawa, 1998; Kollmann & Grubb, 2002; Magnin et al ., 2012; Sosa & Puntieri, 2016). In other instances, it is stated outright, as in Foster’s seminal work (1928) on cataphylls: ‘In a relatively small number of species, e.g.…”

Climate change and population persistence in a hibernating marsupial

“…Contrarily to arctic hibernators, which inhabit alpine forests characterized by a marked seasonal pulse in the trophic offer (e.g. seeds from seasonal deciduous trees in chipmunks or grasses in yellow-bellied marmots [75,77]), Dromiciops lives in evergreen forests where the seasonal increase in food availability is slow and gradual [78][79][80]. Indeed, with climate change, the net primary productivity of temperate rainforests (also known as broadleaved forests) is being reduced due to the concomitant drought effect [6].…”