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Previous issue date: 2013-12-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / O consumo mundial de ?leos vegetais aumentou nos ?ltimos anos devido sua
aplica??o na ind?stria aliment?cia, qu?mica, farmac?utica e, recentemente
energ?tica. Todavia, as sementes oleaginosas das quais esses ?leos s?o
extra?dos envelhecem rapidamente, comprometendo o cultivo e a produtividade
destas. O objetivo deste trabalho foi avaliar o efeito do envelhecimento sobre a
coordena??o dos sistemas antioxidantes da catalase (CAT) e da ascorbato
peroxidase (APX) em c?rtamo e girassol. Para tanto, sementes foram
submetidas a envelhecimento acelerado por 3, 6 e 9 dias e cultivadas em
papel-toalha umedecido durante 72h. Adicionalmente, antes de serem
submetidas ao envelhecimento acelerado, sementes de girassol foram pr?-
tratadas por osmopriming com 10 mM de ascorbato (ASC) ou 3 amino 1,2,4
triazole(3-AT), inibidor espec?fico da CAT. O m?todo de envelhecimento
artificial utilizado foi eficiente para ambas esp?cies, pois promoveu diminui??o
na germina??o, no desenvolvimento de pl?ntulas e no crescimento destas,
principalmente no c?rtamo. O envelhecimento provocou inibi??o da atividade
CAT para ambas as esp?cies e para compensar tal inibi??o, o girassol
aumentou a express?o do mRNA desta enzima, enquanto o c?rtamo mobilizou
mais a atividade da APX. A an?lise da express?o da malato sintase e do
conte?do de a?ucares demonstrou que o girassol consome suas reservas
lip?dicas no estado quiescente, enquanto o c?rtamo ? mais dependente dos
carboidratos. O pr?-tratamento com 3-AT inibiu a atividade CAT e estimulou a
da APX, enquanto o ASC atuou de forma inversa nesses sistemas. Nenhum
dos tratamentos recuperou o decl?nio fisiol?gico decorrente do envelhecimento.
Conclui-se que o envelhecimento alterou significativamente o metabolismo
antioxidante das oleaginosas e, apesar das varia??es interespec?ficas na
resposta a esse processo, a deple??o do sistema antioxidante da CAT foi
comum, deforma que a mensura??o da atividade desta enzima pode ser
utilizada para identifica??o de lotes de sementes envelhecidas. / World consumption of vegetable oils has increased in recent years because of
its application in food, chemical, pharmaceutical and, more recently, energy
industry. However, oilseeds, which these oils are extracted, have low viability,
affecting the cultivation and productivity of these species. The aim of this study
was to analyze the effect of aging on the coordination of catalase (CAT) and
ascorbate peroxidase (APX) antioxidant systems in safflower and sunflower. .
Therefore, seeds were subjected to accelerated aging for 3, 6 and 9 days and
grown in moistened paper towel for 72 hours. Additionally, before accelerated
aging, sunflower seeds were pretreated by osmopriming with 10 mM ascorbate
(ASC) or 3 amino 1,2,4 triazol (3-AT), a specific inhibitor of CAT activitie. The
method of artificial aging used was efficient in both species, because it caused
a decrease in germination, seedling development and growth, especially in
safflower. The aging caused inhibition of CAT activity for both species and to
compensate for such inhibition , sunflower increased mRNA expression of this
enzyme , while safflower mobilized over the activity of APX. Analysis of the
expression of malate synthase and sugar content demonstrated that sunflower
seeds consumes lipid reserves in quiescent state, while the safflower is more
dependent on carbohydrate. Pretreatment with 3-AT inhibited CAT activity and
stimulated the APX, though with ASC acted reverse on these systems. None of
the treatments recovered the physiological decline aging. It is concluded that
aging change the oilseeds antioxidant metabolism, despite interspecies
variations in response to this process, the depletion of the CAT antioxidant
system was common. Because of this we propose that the measurement of
CAT activity can be used to identify aging seed lots.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19977 |
| Date | 18 December 2013 |
| Creators | Castro, ?rika Cristina Pinheiro de |
| Contributors | 79332021368, http://lattes.cnpq.br/3289758851760692, Scortecci, K?tia Castanho, 13451112825, http://lattes.cnpq.br/4808910380593455, Lanza, Luciana Nunes Menolli, 03674305925, http://lattes.cnpq.br/7883331115164146, Chavante, Suely Ferreira, Lima, Jo?o Paulo Matos Santos |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM BIOQU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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