RESUMO

A better knowledge of tree vegetative growth phenology and its relationship to environmental variables is crucial to understanding forest growth dynamics and how climate change may affect it. Less studied than reproductive structures, vegetative growth phenology focuses primarily on the analysis of growing shoots, from buds to leaf fall. In temperate regions, low winter temperatures impose a cessation of vegetative growth shoots and lead to a well-known annual growth cycle pattern for most species. The humid tropics, on the other hand, have less seasonality and contain many more tree species, leading to a diversity of patterns that is still poorly known and understood. The work in this study aims to advance knowledge in this area, focusing specifically on herbarium scans, as herbariums offer the promise of tracking phenology over long periods of time. However, such a study requires a large number of shoots to be able to draw statistically relevant conclusions. We propose to investigate the extent to which the use of deep learning can help detect and type-classify these relatively rare vegetative structures in herbarium collections. Our results demonstrate the relevance of using herbarium data in vegetative phenology research as well as the potential of deep learning approaches for growing shoot detection.

RESUMO

The joint interpretation of phenology and nutritional metabolism provides important data on plant tissues reactivity and the period of gall induction. A population of Aspidosperma macrocarpon Apocynaceae with leaf galls induced by a Pseudophacopteron sp. Psylloidea was studied in Goiás state, Brazil. Assuming the morphological similarity between host leaves and intralaminar galls, a gradient from non-galled leaves towards galls should be generated, establishing a morpho-physiological continuum. The phenology, infestation of galls, and the carbohydrate and nitrogen contents were monthly evaluated in 10-20 individuals, from September 2009 to September 2010. Our objective was to analyze the nutritional status and the establishment of a physiological continuum between the galls and the non-galled leaves of A. macrocarpon. The period of leaf flushing coincided with the highest levels of nitrogen allocated to the new leaves, and to the lowest levels of carbohydrates. The nutrients were previously consumed by the growing leaves, by the time of gall induction. The levels of carbohydrates were higher in galls than in non-galled leaves in time-based analyses, which indicateed their potential sink functionality. The leaves were infested in October, galls developed along the year, and gall senescence took place from March to September, together with host leaves. This first senescent leaves caused insect mortality. The higher availability of nutrients at the moment of gall induction was demonstrated and seems to be important not only for the establishment of the galling insect but also for the responsiveness of the host plant tissues.

La interpretación conjunta de la fenología y el metabolismo nutricional proporciona datos importantes sobre la reacción de tejidos vegetales y el período de inducción de agallas. En el estado de Goiás, Brasil se estudió una población de Aspidosperma macrocarpon Apocynaceae con agallas foliares inducidas por un Pseudophacopteron sp. Psylloidea. Suponiendo que la similitud morfológica entre las hojas del hospedero y las agallas intralaminares genera un gradiente de hojas sin agallas hacia hojas con agallas, se establece un continuo morfo-fisiológico. La fenología, la infestación de las agallas y el contenido de carbohidratos y nitrógeno se evaluaron mensualmente en 10-20 individuos, de septiembre 2009 a septiembre 2010. El objetivo fue analizar el estado nutricional y el establecimiento de un continuo fisiológico entre las hojas que producen agallas y las hojas sin agallas de A. macrocarpon. El período de emergencia de hojas coincidió con los niveles más altos de nitrógeno en las hojas nuevas, y los niveles más bajos de carbohidratos.Los nutrientes se consumieron previamente por las hojas en crecimiento, en el momento de inducción de las agallas. Los niveles de carbohidratos fueron más altos en las hojas con agallas que en aquellas sin agallas, en análisis basados en tiempo, lo que indica su ciclo de funcionalidad potencial. Las hojas hospederas se infestaron en octubre, el desarrollo y la senescencia de las agallas se llevó a cabo entre marzo y septiembre, en las hojas hospederas. Estas primeras hojas senescentes causaron mortalidad de insectos. Hay mayor disponibilidad de nutrientes en el momento de la inducción de las agallas y parece ser importante no sólo para el establecimiento del insecto que produce agallas, sino también para la capacidad de respuesta de los tejidos de la planta hospedera.

Assuntos

RESUMO

Chamaedorea bartlingiana is a dioecious palm that grows in the cloud forest understories of the Venezuelan Andes. Age and sexual differences in phenology and reproductive patterns were studied in labelled individuals of all age categories. This species has long-lived leaves and low leaf production, both characteristic of understory plants. Growth rates are lower in juveniles than in adults and in females than in males, as in other palms. Male and female individuals show different reproductive patterns. Male inflorescences are always produced at the same rate and the probability of surviving until anthesis is constant. Females produce reproductive buds at the same rate as males, but these buds have a 35% probability of becoming a ripe infrutescence if the plant has infrutescences already growing, and 70% if it does not. This pattern and the slow growth of inflorescences (1 year for males from bud to flowers, 2 years for females from bud to ripe fruits) cause a pluriannual reproductive pattern at the population level. Field germination does not follow this pattern, but shows one annual peak probably related to environmental conditions.