Banca de QUALIFICAÇÃO: MARIA CAROLINA SARTO FERNANDES RODRIGUES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA CAROLINA SARTO FERNANDES RODRIGUES
DATE: 26/06/2023
TIME: 14:00
LOCAL: Auditório da Pós-graduação - UFRA/Belém
TITLE:

RHIZOBACTERIA AND FERTIACTYL GZ® INCREASE TOLERANCE TO WATER DEFICIT AND IMPROVE REHYDRATION OF AÇAI PALM SEEDLINGS

KEY WORDS:

Euterpe oleracea Mart. Biostimulants. Dry. Water recovery.

PAGES: 45
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitossanidade
SPECIALTY: Microbiologia Agrícola
SUMMARY:

The açai palm (Euterpe oleracea Mart.), native to Central and South America, is considered a palm tree of great economic importance in the Amazon region. Brazil is the world's largest producer and the growing demand for the fruit has stimulated a change in the planting system, from native to commercial plantations on terra firme. However, the high sensitivity to water deficit limits the production of seedlings in nurseries and hinders the expansion of commercial plantations. Biostimulants can be used as an efficient strategy to reduce seedling losses, as they increase tolerance to the negative effects of water deficit (DH) and help plants recover after rehydration. The objective of the study was to alleviate the effect of the biostimulants Bacillus subtilis (BS) and the commercial biostimulants Fertiactyl GZ® (BC) on changes in gas exchange, oxidative stress and osmotic adjustment caused by water deficit and to analyze the capacity of biostimulated seedlings in water recovery after a dry period. The study was divided into two chapters, the first referring to the imposition of water deficit with four treatments and 6 repetitions each. The treatments consisted of non-inoculated plants (control) and inoculated with BS, BC and a combination of BS + BC, which were evaluated under full irrigation conditions and after 7 and 14 days of water suspension. At 7 days of water deficit, seedlings biostimulated with BC, BS and BS+BC increased net photosynthesis by 76%, 24% and 36% respectively (A); 100%, 87% and 40% stomatal conductance (gs); 75%, 25% and 47% the carboxylation efficiency (A/Ci) and 39%, 27% the transpiration (E). At 14 days of water deficit, plants with BC and BS+BC increased by 71% and 35% to A; 100% and 63% on gas; 75% and 25% to A/Ci and BC 64% to E, compared to plants without biostimulants. At 14 days of water suspension, Ψw was 24% and 35% higher in seedlings biostimulated with BS and BC, compared to non-biostimulated ones. The proline content was higher in biostimulated seedlings, being more expressive in plants with BS, 75% higher than the control. The MDA content reduced by 20.34% and 14.6% for BC and BS+BC and the highest SOD activity was found for BC and BS+BC, with 31.23% and 27.44%, respectively, compared to to control. The second chapter aimed to evaluate the recovery of açaí seedlings after rehydration and was composed of 5 treatments and 6 repetitions each. The treatments were plants inoculated with BS, BC, combination of BS + BC and non-inoculated (DH control) under water deficit and non-inoculated plants under irrigation (IRR control), which were evaluated in water recovery condition after 0 days, 7 days and 14 days of rehydration. In condition of 7 days of rehydration, when compared to control in DH, all biostimulated plants had higher A and A/Ci; plants with BC increased 44.44% at gs and 34.8% at E and with BS+BC increased by 37.25% at A/E. When compared to the IRR control, all treatments showed lower A, gs, E and A/Ci, with the exception of the mean Ci of plants with BC and the mean A/E of BS+BC which were equal to those of the irrigated control plants . At 14 days of rehydration, plants inoculated with BC and BS+BC presented, respectively, 16.77% and 20.17% higher A; 7.44% and 6.82% lower Ci; 22.73% and 26.09% higher A/Ci, compared to control in HD. Plants with BC had 24.07% and 29.14% higher gs and E, respectively, in relation to the DH control. Compared to the IRR control, the biostimulated plants showed the same average of A and A/Ci and for Ci, there was no statistical difference for biostimulated plants, including for the DH control. Plants with BC, presented the same means of gs, E and A/E, in relation to the 100% irrigated control plants. The inoculation of açaí seedlings with BS, BC and BS+BC, mitigate the damage caused by water deficit by inducing osmotic adjustment due to the accumulation of proline, activate the enzymatic system of antioxidant defense (SOD) to alleviate oxidative stress, help in the protection of the photosynthetic machinery, improve the physiological performance and promote the best water recovery of the plants.

BANKING MEMBERS:
Presidente - 1065086 - GLEDSON LUIZ SALGADO DE CASTRO
Externo ao Programa - 071.193.302-25 - WALTER VELLASCO DUARTE SILVESTRE - UFRA
Externo à Instituição - FLÁVIO JOSÉ RODRIGUES CRUZ
Externo à Instituição - JOSUÉ VALENTE LIMA