The distinct roles of water table depth and soil properties in controlling alternative woodland-grassland states in the Cerrado.

Open grassy vegetation and forests share riparian zones across the Neotropical savannas, characterizing alternative stable states. However, factors determining the occurrence and maintenance of each vegetation type are yet to be elucidated. To disentangle the role of environmental factors (soil properties and groundwater depth) constraining tree colonization of wet grasslands in the Cerrado, we assessed tree establishment during the early seedling and sapling stages and the influence of these factors on leaf gas exchange and leaf water potential of tree saplings.

Automatic Leaf Epidermis Assessment Using Fourier Descriptors in Texture Images.

The identification of plant species is not a trivial task, since it is carried out by experts and depends on the presence of fruits, flowers and leaves. However, fruits and flowers are not available throughout the year, while leaves are accessible most of the year. In order to assist the specialized work of species identification, methods of texture image analysis are used to extract characteristics from samples of imaged leaves and thus predict the species.

Leaf epidermis images for robust identification of plants.

This paper proposes a methodology for plant analysis and identification based on extracting texture features from microscopic images of leaf epidermis. All the experiments were carried out using 32 plant species with 309 epidermal samples captured by an optical microscope coupled to a digital camera. The results of the computational methods using texture features were compared to the conventional approach, where quantitative measurements of stomatal traits (density, length and width) were manually obtained.

Plant Identification Based on Leaf Midrib Cross-Section Images Using Fractal Descriptors.

The correct identification of plants is a common necessity not only to researchers but also to the lay public. Recently, computational methods have been employed to facilitate this task, however, there are few studies front of the wide diversity of plants occurring in the world. This study proposes to analyse images obtained from cross-sections of leaf midrib using fractal descriptors.

Parameters affecting the early seedling development of four neotropical trees under oxygen deprivation stress.

Some of the parameters that determine flooding resistance-and consequently habitat zonation-were investigated in four neotropical trees (Schizolobium parahyba, Sebastiania commersoniana, Erythrina speciosa and Sesbania virgata). The constitutive parameters of seeds (size, nature and amount of reserves) only partly influenced resistance to flooding, mainly through a high carbohydrate : size ratio. Parameters describing metabolic efficiency under stress conditions were more important.