Detalhes bibliográficos
| Ano de defesa: |
2017 |
| Autor(a) principal: |
BARROSO, Jorcely Gonçalves
 |
| Orientador(a): |
RODAL, Maria Jesus Nogueira |
| Banca de defesa: |
SALIMON, Cleber Ibraim,
BARBOSA, Dilosa Carvalho de Alencar,
SAMPAIO, Everardo Valadares de Sá Barretto,
MEUNIER, Isabelle Maria Jacqueline |
| Tipo de documento: |
Tese
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal Rural de Pernambuco
|
| Programa de Pós-Graduação: |
Programa de Pós-Graduação em Ciências Florestais
|
| Departamento: |
Departamento de Ciência Florestal
|
| País: |
Brasil
|
| Palavras-chave em Português: |
|
| Área do conhecimento CNPq: |
|
| Link de acesso: |
http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/7402
|
Resumo: |
Light is a determining resource to seedlings growth and survival, even in environments where light is not necessarily limiting, such as in Seasonally Dry Tropical forests. The effect of light gradient in traits related to resource acquisition and adaptive plasticity in Caatinga's woody species are not known. This study aimed to investigate the influence of a light gradient in morphological and allocational traits in seedlings of ten woody species, widely distributed in semiarid Northeast Brazil. These species represent a vast combination of phenologic traits, water potential and wood density. We tested the following hypotheses: 1) specific leaf area (SLA) plasticity responds positively to relative growth rate (RGR), therefore being adaptive (Chapter One); 2) the effect of light gradient results in a coordinated variation among root and leaf traits (Chapter Two). The experiment was carried in Serra Talhada, PE and was comprised of three treatments, 100%, 60% e 30% light, where seedlings were watered three times a week, based on local evapotranspiration. We evaluated nine morphological and allocational traits, known for responding to light availability changes. RGR was not correlated with plastic to SLA, but was with plastic to biomass allocation to roots and stem. The greatest RGR were observed in high wood density deciduous species and the lowest RGR were observed in evergreen species. The species which responded significantly to light gradient were Bauhinia cheilantha which grew faster at 60% light, and Cynophalla flexuosa, with the slowest growth at 30% light. There was no coordinated variation between root and leaf traits and light gradient. Species did not differ in specific root length, although there were some significant difference between total root length and root dry mass. Therefore, none of our hypotheses were confirmed. Such results reveal a complex relation among leaves and roots traits, with a diversity of mechanisms allowing the coexistence of species and with plasticity neutralizing a great part of niche differentiation. Also, our results suggest that root and stalk traits plasticity could be important for shade tolerance, probably related to species capacity to deal with heterogeneity in resource availability. |
