Name: Carlos Luis Sanchez Fonseca
Type: PhD thesis
Publication date: 20/09/2021
Advisor:
Name |
Role |
|---|---|
| Fábio Murilo DaMatta | Advisor * |
| Geraldo Rogério Faustini Cuzzuol | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Bernardo Pretti Becacici Macieira | External Alternate * |
| Diolina Moura Silva | Internal Examiner * |
| Geraldo Rogério Faustini Cuzzuol | Advisor * |
| José Eduardo Macedo Pezzopane | External Examiner * |
| Moemy Gomes de Moraes | External Examiner * |
| Paulo Cezar Cavatte | Internal Examiner * |
Summary: According to IPCC reports, environmental disturbances resulting from climate change
are predicted for the Brazilian region under the domain of the Atlantic Forest. In the
Northeast, warming and prolonged drought are projected. This climate scenario can
compromise the physiological processes, growth and survival of native species of the
Atlantic Forest. Including the country`s symbol species, Paubrasilia echinata. Seeking
to gather information about the physiological strategies of this species in the face of
drought, we carried out this study in order to characterize the photosynthetic responses
and the dynamics of carbon allocation in two morphotypes of the species, one is shadetolerant (small leaf morphotype) and the other sun-tolerant (medium leaf morphotype).
The first stage of this study, was evaluated the water potential, electrolyte leakage, gas
exchange and transient chlorophyll a fluorescence of plants of the two morphotypes of
P. echinata under water suspension followed by rehydration. In the complementary
step, was evaluated the dynamics of the allocation of non-structural (sugars and
starch) and structural (cell wall polymers: cellulose, hemicelluloses and lignin) carbon.
It was recorded that the sun-tolerant morphotype, well adapted to drier and warmer
environments, when subjected to water deficit presents a less pronounced decline in
leaf water potential, photosynthesis and fluorescence parameters. Unlike the shadetolerant morphotype, which showed less tolerance under the same treatment
conditions. The greater resistance of the sun-tolerant morphotype to drought was
attributed to its greater capacity to accumulate sugars and lignification of its tissues.
Thus, the habits of the morphotypes reflected in their physiological strategies to adjust
the allocation of carbohydrates in drought tolerance. Concluding that, if the drought of
climate change in the Atlantic Forest domain regions settles in the next decades,
possibly the natural population of shade-tolerant morphotype may suffer reduction, due
to its lower tolerance to water deficit in relation to the sun-tolerant morphotype.
