Banca de QUALIFICAÇÃO: FLÁVIA RAPHAELA CARVALHO MIRANDA GUEDES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : FLÁVIA RAPHAELA CARVALHO MIRANDA GUEDES
DATA : 02/06/2020
HORA: 15:00
LOCAL: Auditório do PGAGRO/UFRA
TÍTULO:

FOLIAR APPLICATION OF 24-EPIBRASSINOLIDE MITIGATES THE NEGATIVE EFFECTS ON PHOTOSYNTHESIS, NUTRITIONAL CONTENT, ANTIOXIDANT SYSTEM AND ANATOMICAL PARAMETERS IN RICE PLANTS UNDER LEAD TOXICITY

PALAVRAS-CHAVES:

EBR ● Chlorophyll fluorescence ● Environmental pollutant ● Gas exchage ● Net photosynthetic rate ● Oryza sativa L.

PÁGINAS: 52
RESUMO:

Lead (Pb) is an environmental pollutant that negatively affects the rice plant, causing damage to the chloroplast structure, chlorophyll synthesis, decreasing photosynthetic activity and hindering growth. 24-epibrassinolide (EBR) is a natural steroid, used to regulate plant growth and mitigate possible toxic effects caused by abiotic stresses. The objective of this research is to determine if the EBR mitigates the toxic effects of lead in rice, evaluating the possible responses in the chlorophyll fluorescence, gas exchange, nutritional concentrations and anatomical characteristics. The experiment was randomized with four treatments, including two lead treatments (0 and 200µM PbCl2, described with - Pb and + Pb, respectively) and two treatments with brassinosteroid (0 and 100nM EBR, described as - EBR and + EBR, respectively). Our results showed that plants exposed to Pb toxicity had negative disturbances, however, the treatment with EBR showed positive increases in the proportions Ca+2/Pb+2 (41% in the root and 46% in the shoot) and Mg+2/ Pb+2 (32% in the root and 26% in the shoot) and benefits in chlorophyll fluorescence, attenuation in photoinhibition in photosystem II and protection against damage caused by the production of reactive oxygen species (ROS). Furthemore, EBR led to improvements in gas exchange, improving CO2 fixation. This study showed that EBR mitigated the toxic effects of Pb, increasing the activities of the antioxidant enzymes (SOD, CAT, APX and POX) and decreasing the damage to the chloroplast membrane, as confirmed by the increase in chlorophyll content. These results prove that EBR mitigates the toxic effects of Pb in rice plants

MEMBROS DA BANCA:
Presidente - 1803899 - ALLAN KLYNGER DA SILVA LOBATO
Interno - 030.493.086-56 - SILVIO JUNIO RAMOS - ITV
Externo à Instituição - FLÁVIO JOSÉ RODRIGUES CRUZ - UFRPE
Externo à Instituição - RODRIGO MOREIRA DA SILVA - USP