Banca de QUALIFICAÇÃO: SARA CAROLINE PINTO DE ALMEIDA SANTOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : SARA CAROLINE PINTO DE ALMEIDA SANTOS
DATA : 05/04/2019
HORA: 09:00
LOCAL: Sala Imburana
TÍTULO:

Abiotic stress in castor bean cultivars (Ricinus communis L.)

PALAVRAS-CHAVES:

Recurrent drought. Salt stress. Antioxidant system. Lipid peroxidation. BRS Energia. BRS Gabriela

PÁGINAS: 107
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Abiotic stresses are important for the development and productivity. For castor bean (Ricinus communis L.) the oil production has a big importance as the ricinoleic acid is used for biofuel and others industry applications. Therefore, this study aimed to understand the different responses from two castor bean cultivars to drought and salt stress (abiotic stress). In other to do this, castor bean plants from cultivars BRS Energia and BRS Gabriela were submitted to drought stress (T1: one drought, T2: drought with recovery, T3: recurrent drought). Salt stress was also performed under controlled growth conditions with different NaCl concentration using a hydroponics system (0, 50, 100, 150 and 200 mM). Morphophysiological and biochemical parameters were analyzed and a protocol extraction for total soluble proteins from leaves and seed tissues were also set up for future proteomic analysis. In all drought treatments, the two cultivars had a significant reduction in leaf number. It was observed more than 70% reduction for BRS Energia at T1. Moreover, the moisture percentage determined in BRS Energia leaves had an increased in almost 10% after two periods of drought, this result suggested a water maintenance for this tissue even with the stress condition. The lipid peroxidation parameter in leaves suggested an oxidative stress for both cultivars after the recurrent drought. In the same way, it was verified an increase from the APX activity after the water recovery for BRS Gabriela leaves and, after the recurrent drought for BRS Energia leaves. For the roots tissues, it was observed an increase in the APX activity after the first drought for BRS Energia cultivar, and only at the recurrent drought it was observed for BRS Gabriela plants. Moreover, POX increased its activity after drought recovery for BRS Energia. Furthermore, it was also analyzed the oil content and it was observed a reduction for BRS Gabriela seeds after recurrent drought (T3). When castor bean plants were submitted to salt stress, it was observed that BRS Energia plants had a decrease in relative water content (RWC) as well as for the moisture percentage at the highest concentration of salt treatment. On the other hand, there was no stress for photosynthesis as the chlorophyll content increased at 100 mM NaCl treatment. For the antioxidant enzymes, it has been observed an increase for APX and POX activities in the leaves with 100 mM NaCl and for CAT antioxidant enzyme when exposed to 150 mM. For roots, it was observed an increase for APX and POX activities at 200 mM NaCl. The leakage of electrolytes indicates a possible damage to leaf tissue membranes, was it reached 95% at 150 mM and 200 mM NaCl. Then, these data allow us to propose that these plants were able to modulate the antioxidant system, depending on the cultivar and the tissue, in order to mitigate the deleterious effects promoted by ROS. The set up from a protocol for protein extraction allowed us to obtain a reproductible protocol was important for peptide sequencing (proteomic approach). Then all these information will help to understand the possible mechanisms of tolerance to abiotic stress from these two castor bean cultivars.

MEMBROS DA BANCA:
Presidente - 1549705 - ADRIANA FERREIRA UCHOA
Externa ao Programa - 2294466 - CRISTIANE ELIZABETH COSTA DE MACEDO
Interno - 1228866 - EDUARDO LUIZ VOIGT