Banca de DEFESA: ARTHUR GOMES LIMA DA SILVA
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : ARTHUR GOMES LIMA DA SILVA
DATE: 25/08/2021
TIME: 14:00
LOCAL: meet.google.com/sqo-snas-izr
TITLE:
Edaphic conditions influence the tolerance of Myracrodruon urundeuva Allemão (Anacardiaceae) to water deficit and its subsequent recovery
KEY WORDS:
Seasonally dry tropical forest, climate changes, gas exchange.
PAGES: 57
BIG AREA: Ciências Biológicas
AREA: Botânica
SUBÁREA: Fisiologia Vegetal
SUMMARY:
Myracrodruon urundeuva Allemão is a tree species native to the seasonally dry tropical forest. It is important in the recovery plans of degraded areas and a key species for the maintenance of the biodiversity of this biome. However, M. urundeuva is on the red list of species from the Brazilian flora threatened with extinction and it is classified as a high priority for conservation. In semiarid regions, the water regime is pointed out as the variable with the greatest influence on the distribution of plant species. However, some studies suggest that the type of soil can affect the tolerance of plants to water stress. Since M. urundeuva occurs in different types of soil, the different physicochemical properties of these soils may, to some degree, influence the physiological changes triggered by water deficit, as it has been detected in other plant species. Due to the risk of changes in the distribution pattern of M. urundeuva as a result of climate change, studies that investigate the influence of other factors, such as soil, that are associated with water deficit on the physiology of M. urundeuva are extremely relevant. The experiment was carried out in a greenhouse in a completely randomized design and in a 2x2 factorial scheme. A variance analysis was used to assess the effects of two types of soil: sandy clay loam and sandy, and two water regimes: irrigated and water deficit (imposed by the suspension of irrigation until photosynthetic rates were close to zero, with subsequent rehydration until recovery) on gas exchange, maximum and effective quantum efficiency of PSII (Fv/Fm and ΦPSII), water status (Ψwleaf), relative chlorophyll content and concentration of organic compounds (proteins, amino acids, proline and sugars). The type of soil influenced the physiological changes, triggered by the water deficit, in the instantaneous water use efficiency, predawn Ψwleaf and amino acid content. In sandy soil, M. urundeuva took longer to reach photosynthetic rates close to zero after the suspension of irrigation, and needed less time to recover after rehydration. Plants in clay loam soil, in turn, were able to increase water use efficiency (WUE) under moderate water deficit (a common situation on the seasonally dry tropical forest) and presented a better water status under severe water stress. Plants in sandy clay loam soils were also able to increase leaf amino acid content under water stress. Despite the severe water stress, none of the plants had reduced Fv/Fm. However, plants in sandy clay loam soil had lower Fv/Fm (at midday) and ΦPSII. On the other hand, these plants were able to increase Fv/Fm (at midday), ΦPSII and WUE after rehydration. In conclusion, M. urundeuva cultivated in sandy soil tolerates water deficit for longer and needs less time to recover, showing the ability to maintain its PSII quantum efficiency even under severe stress. However, plants in clay loam soil had better stomatal control, which reflected in the increase in WUE, ensuring a better water conservation during severe water stress, as well as the ability to increase quantum efficiency of the PSII and the WUE during the recovery.
BANKING MEMBERS:
Presidente - 1916144 - GILBERTO COSTA JUSTINO
Interna - 2024367 - MELISSA FONTES LANDELL
Externo à Instituição - MARCIEL JOSÉ FERREIRA - UFAM
Externa à Instituição - LILIANE SANTOS DE CAMARGOS - UNESP