Fisiologia e indicadores de estresse em árvores crescendo em ambientes alagados pela hidroelétrica de Balbina na Amazônia central
Human activities can promote an increase of flooding areas as consequence of the hydroelectric dam construction and the increase of the risks and the severity of the inundations provoked by climatic changes. For this, it is necessary an increase in ecophysiological studies of plants growing in fl...
| Autor principal: | Santos Júnior, Ulysses Moreira dos |
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| Grau: | Tese |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia – INPA
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/4976 http://lattes.cnpq.br/8147510954209443 |
| Resumo: |
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Human activities can promote an increase of flooding areas as consequence of the
hydroelectric dam construction and the increase of the risks and the severity of the
inundations provoked by climatic changes. For this, it is necessary an increase in
ecophysiological studies of plants growing in flooded areas artificial and naturally with the
objective to comprehend as the forests will response the environmental changes. Thus, the
objective of this thesis was analyse the efects of flooding on survive strategies, gas exchanges,
nutrient and pigment contents, variables of fluorescence transients and performance index in
flooding tolerant and non tolerant species growing in flooding áreas by Uatumã river
downstream and upstream of the Balbina Dam, Presidente Figueiredo-AM (01o 55'S e 59o 28'
W). Besides, were evaluated the viability and the utilization of fast, easy and non destructive
tools as fluorometer (PEA) to acess physiological parameters and in the monitoring the plants
behavior on flooding areas. The studied species were: Nectandra amazonum (Na),
Macrolobium angustifolium (Ma), Alchornea discolor (Ad), Brosimum lactescens (Bl), Cassia
reticulata (Cr), Genipa spruceana (Gs), Parinari excelsa (Pe); Cecropia concolor (Cc),
Vismia guianensis (Vg) e Vismia japurensis (Vj), in which the last three are non flooding
tolerant. For the survival rates were observed that the tolerant species exhibited values above
90% while the non tolerant species exhibited values below 20%. In non tolerant species the
physiological changes induced by the flooding were much more intense than in the tolerant
species. In the flooded period the non tolerant species exhibited reductions of maximal net
photosynthesis (Pnmax) and transpiration rate at 2000 mmol (fótons) m-2 s-1 (E2000) above 70%.
The reduction in the values of Pnmax and E2000 can especially be attributed to the stomatic
closure in flooded period. In addition, did the flooding also induce a decrease in the pigment
contents and in the use efficiency of the light energy for the reduction of CO2 to carbohydrate
as demonstrated by the values of apparent quantum yield ( ) and performance index (PIABS).
The decrease of the photochemical yields might also have contributed to the reduction of the
photosynthesis values in non tolerant species in flooded period. In the tolerant species the
changes induced on gas exchanges, pigment content ando and fluorescence parameters were
slighter compared to non tolerant species. On leaf nutrient contents, the flooding induced
decrease in the concentrations of N, P and Cu and an increase in the concentrations of Fe, Mn,
Zn and Na of the species during flooding period in both groups. It was also studied the effects
of the increase of the temperature on the gas exchanges of plants under flooding in which was
demonstrated that the increase of leaf temperature can promote reduction of gas exchanges,
especially, in the flooded period. Its occur because due the reduction of the stomatal
conductance is induced a loss of the capacity of the plant to maintaining the leaf temperature
in appropriate levels promoting consequently damages to the enzymatic apparatus of the
photosynthesis. As the evaluation of fast, easy and non destructive tools to access
physiological parameters was demonstrated that the fluorometer (PEA) was efficiency to
detailed screening of the changes in the capture and use of the light energy in the reduction of
CO2. This tool can be useful for the monitoring the effects of flooding on species as well as to
be used for the selection of species to be used in projects reforestation of environments
flooded antropic and naturally. Finally, the analysis of three models to estimate
photosynthetic parameters, as non rectangular hyperbola (NRH), rectangular hyperbola (RH)
and exponential (EXP), demonstrated that there are high differences among them and that
those differences should be taken into account in the projects of environmental modelling.
The best estimates were obtained when the value of measured Rd was added to the model and
the models EXP and RH were the ones that came as more appropriate compared to model
NRH. |