Name: LILIANE BALDAN ZANI
Type: PhD thesis
Publication date: 20/12/2017
Advisor:
Name |
Role |
|---|---|
| Luis Fernando Tavares de Menezes | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ANGELA PIERRE VITORIA | External Examiner * |
| Diolina Moura Silva | Internal Examiner * |
| Geraldo Rogério Faustini Cuzzuol | Internal Examiner * |
| Glória Mattalana Tobón | External Alternate * |
| Luis Fernando Tavares de Menezes | Advisor * |
| Marcelo da Costa Souza | External Examiner * |
| Valéria de Oliveira Fernandes | Internal Alternate * |
Summary: The speed with which climate changes are occurring is a massive threat to the
environment. It is not known how the plants will respond to these changes, since there is little information about their ecophysiological responses to changes in temperature and precipitation patterns. In this way, it is important to identify the possible vulnerabilities of species in global climate change scenarios. The objective of this work was to evaluate the isolated and combined effects of temperature increase (2°C) and rainfall volume (25%) on biomass production, reproductive phenology, gas exchange and chlorophyll a fluorescence of Allagoptera arenaria in restinga environment open top chambers (OTC's) and rain gutters. A total of 40 A.
arenaria shrubs were selected from four treatments, open-control environment (C), 25% (P) rainfall increase, 2°C (T) temperature increase and 2°C and pluviometric volume in 25% (TP). The results showed that OTC's and gutters were effective in simulating the effects of proposed climate changes. The values of aerial biomass variation were higher for the TP treatment when compared to the T treatment, which, in turn, presented more reproductive cycles throughout the evaluated period. In this way it was possible to verify two different aspects between the results in the sense of allocation between biomass and reproduction. Plants submitted to TP treatment had the highest rates of assimilation of CO2 (A), stomatal conductance (gs), and transpiration (E), while T treatment presented the lowest rates in the samplings initially. As for the interaction between the photosynthetic variables, it was possible to affirm that in the months of November/2015, February/2016 and June/2016 there was a greater variation between the variables of gas exchange, WHEREas in November/2016 there were few significant alterations between these variables. The treatment T presented a considerable reduction in transient responses of chlorophyll a fluorescence and the increase in pluviometric volume contributed to soften the effects of temperature increase in TP treatment. In P, no differences were observed in relation to the control for the analyzes performed. With the climatic changes it is possible that, A. arenaria develops mechanisms to survive the temperature increase and the increase of the pluviometric volume can favor this process. Possible future temperature increases may shorten the reproductive cycle of A. arenaria in an attempt to guarantee the adaptive and evolutionary success of this species. In the
restinga environment, this species already deals with adverse conditions and higher 10 temperature tolerance can be acquired as a mechanism of adaptation to the altered growth environment.
Keywords: Climate change aerial biomass phenology photosynthesis
Allagoptera arenaria restinga
