Banca de DEFESA: LUCÉLIA ROSA DE JESUS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: LUCÉLIA ROSA DE JESUS
DATA: 17/02/2017
HORA: 15:30
LOCAL: Auditório PPAGRO/UFRA
TÍTULO:

Silicon reduces aluminum accumulation and mitigates toxic effects in cowpea plants

PALAVRAS-CHAVES:

Beneficial element ● Growth ● Metal toxicity ● Photochemical efficiency of PSII ● Vigna unguiculata

PÁGINAS: 54
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Fisiologia de Plantas Cultivadas
RESUMO:

Aluminum (Al) is the third most abundant metal in the Earth’s surface, and Al toxicity promotes several negative effects in plant metabolism. Silicon (Si) is the second most common mineral in soil and is considered a beneficial element for plants, improving their tolerance to biotic and abiotic stresses. The aim of this study is to determine whether Si can reduce the accumulation of Al, explain the possible contribution of Si in mitigating Al toxicity, and indicate the better Si dose-response for cowpea plants. The experiment had a factorial design with two levels of aluminium (0 and 10 mM Al) and three levels of silicon (0, 1.25 and 2.50 mM Si). The utilization of Si in plants exposed to Al toxicity contributed to significant reductions in the Al contents of all tissues, corresponding to reductions of 51%, 29% and 41% in roots, stems and leaves, respectively, upon treatment with 2.50 mM Si + 10 mM Al compared to the control treatment (0 mM Si + 10 mM Al). Al toxicity promoted decreases in ΦPSII, qP and ETR, whereas 2.50 mM Si induced increases of 54%, 185% and 29%, respectively. Plants exposed to Al had lower values of PN, WUE and PN/Ci, whereas Si application at a concentration of 2.50 mM yielded improvements of 53%, 32% and 67%, respectively. Al exposure increased SOD, CAT, APX and POX activities, whereas treatment with 2.50 mM Si + 10 mM Al produced significant variations of 72%, 97%, 48% and 32%, respectively, compared to 0 mM Si + 10 mM Al. Our results proved that Si reduced the Al contents and bioconcentration factors for Al in all tissues. Si also improved the photochemical efficiency of PSII, gas exchange, pigments and antioxidant enzymes, contributing to a reduction in the accumulation of oxidative compounds. These benefits corroborate the multiple roles exercised by Si in metabolism and reveal that Si immobilizes the Al in roots and reduce the accumulation of this metal in other organs, mitigating the damage caused by Al in cowpea plants. In relation to dose-response, plants exposed to 1.25 mM Si without Al presented better results in terms of growth, whereas the toxic effects of plants exposed to Al were mitigated with 2.50 mM Si.

MEMBROS DA BANCA:
Presidente - 1803899 - ALLAN KLYNGER DA SILVA LOBATO
Externo ao Programa - 2595267 - CANDIDO FERREIRA DE OLIVEIRA NETO
Externo à Instituição - DOUGLAS JOSÉ MARQUES - NENHUMA
Externo à Instituição - RAFAEL SILVA GUEDES - NENHUMA