Banca de QUALIFICAÇÃO: MAYARA LUÍZA ALVES PEREIRA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MAYARA LUÍZA ALVES PEREIRA
DATE: 08/07/2021
TIME: 13:50
LOCAL: Google Meets
TITLE:

Morphology and ecological function of lenticels in wood trees from the Caatinga dry forest

KEY WORDS:

Structural changes;closing layer;bark anatomy;seasonal changes;functional anatomy;phelogen;secondary growth;cork anatomy;lenticel anatomy

PAGES: 64
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

During primary growth, the epidermis lines the plant's body, and its tabular cells, juxtaposed and cuticularized, share space with the stomata, responsible for carrying out gas exchange in the first stage of plant development. In woody species (i.e. plants that develop secondary growth), the epidermis is replaced by the periderm, composed of phellogen, which produces pheloderm for the interior and felem (or suber) for the exterior, forming the cork tissue. The stomata are replaced by lenticels even in the presence of the epidermis. Lenticels are pore-like structures that originate under the stomata in places where the phelogen has a more intense meristematic activity. Unlike cork cells, which are tightly arranged and have suberified walls, lenticels are made up of cells with a rounded shape and delicate walls, loosely organized, characterized by the presence of large intercellular spaces between the juxtaposed cork cells. The characteristic structure of lenticels is directly related to their known functions, with the intercellular spaces allowing a high permeability to air, water vapor, aerosols, in addition to contributing to transpiration. These structures are present in a variety of organs and species of terrestrial plants, presenting different adaptations that help individuals to establish themselves under different environmental conditions. The morphology of lenticels varies among the different woody species in which they occur, and their ecological function is still under discussion. This variation, in line with stem characteristics, allows the lenticels to help identify woody species. Knowing that most studies on lenticels focus on temperate forests, this dissertation seeks to discuss a little about the morphology, functional structure and influence of lenticels on the survival of communities planted in dry environments, being divided into two chapters. The first chapter aims to describe the internal and external morphology of the lenticels and stem of 14 woody species from the Caatinga, in order to show possible morphological patterns and separate them into functional types. Individual samples were collected for each species and histological slides were prepared for anatomical description. Additionally, lenticels were analyzed using scanning electron microscopy and fresh material for descriptions of external morphology. We found that there is a difference between the morphological characteristics of the lenticels, as well as the stem, demonstrating the potential of these structures to identify individuals in the absence of flowers, fruits and leaves. We also observed two patterns of structural alternation in lenticels, suggesting that different species may adopt different strategies depending on environmental conditions. The second chapter seeks to investigate how lenticels can influence the survival of individuals belonging to 14 species in the Caatinga through planted communities with different diversities. For this purpose, samples were collected from individuals to count the number and area of lenticels in the laboratory. Survival data were collected in a field experiment with 4704 seedlings of 16 native species divided into 147 communities, with 5 levels of diversity. We calculated whether there is a difference between number and average area of lenticels between species through generalized linear models and built a generalized linear mixed model to understand whether the functional characteristic of lenticels influences the survival of communities over time. The number of lenticels differed among species, however the average area was only significantly different in one species. As for survival in the communities, there was a variation depending on the interaction between the number of lenticels and the year observed.

BANKING MEMBERS:
Presidente - 1677189 - GISLENE MARIA DA SILVA GANADE
Externa ao Programa - 3240812 - CLARISSA GOUVEIA FONTES
Externo à Instituição - GIULIANO MASELLI LOCOSSELLI