Banca de DEFESA: TADEU AUGUSTO VAN TOL DE CASTRO
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : TADEU AUGUSTO VAN TOL DE CASTRO
DATA : 02/09/2019
HORA: 13:30
LOCAL: Sala 24 do Departamento de Solos
TÍTULO:
Structure-Property-Bioacitivity Relationship of Different Humic Acids and their Effects in Rice Plants (Oryza sativa L)
PALAVRAS-CHAVES:
Humic substances. Characterization. Biological activity. Hydrical stress.
PÁGINAS: 117
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Ciência do Solo
ESPECIALIDADE: Microbiologia e Bioquímica do Solo
RESUMO:
The following dissertation aimed to study three humic acids (HA) extracted from different source materials, one of vermicompost (HAVC), one of organosol (HASOIL) and one of Rio Negro sediments - AM (HARN), evaluating their structures, properties and functions in the metabolism and development of rice plants under normal growing conditions and under water stress. Chapter I presents the results concerning the physicochemical characterization (solid state nuclear magnetic resonance - 13C NMR CP / MAS and dynamic light scattering - DLS) of the three types of humic acids. HASOIL presented more aromatic characteristics than HARN and HAVC, thus conferring greater hydrophobicity. HAVC had the highest polarity index and lowest hydrophobicity. HASOIL and HARN showed the largest particle populations at pH 7.0 between 0 and 500 nm in hydrodynamic diameter, in relation to humic acid from vermicompost. However, the average particle diameter at pH = 7 shows that HAVC had larger particles compared to the others. The objective of Chapter II was to evaluate and discuss the effects of the three HA, previously characterized, on the morphology, growth and metabolism of rice (Oryza sativa L.) plants of the BRS Emerald variety, as well as establish a relationship between their structures and physical-chemical properties with the bioactivity they exert. An increase in photosynthetic performance was observed in plants treated with HA extracted from different materials after an initial decrease in order to accelerate metabolic activities aiming at acclimatization and plant protection. In general, all humic acids stimulated the metabolism and development of plants, but in a different way, being the activity exerted dependent on their structural characteristics and properties. There were different modifications in the structures present in the roots by the effect of humic acids, associated with the development of the plant cell wall. The HAVC was considered the best bioactivity, as it was responsible for the most intense increase in the production of fresh and dry biomass in the roots, sheaths and leaves of the plants, besides presenting greater stimuli in the emission of roots and increase in root volume. The levels of soluble metabolites also indicate that the plants treated with this HA were the most efficient in using nitrogen for its development. Chapter III shows the results obtained by the application of vermicompost humic acid in rice (Oryza sativa L.) plants of the BRS Emerald variety subjected to water deficiency. HAVC preserved the photosynthetic performance index in plants under water stress, being the response mechanisms for HA application faster than those for stress response. HA was also responsible for stimulating the quantity, length, area, volume and diameter of roots of plants cultivated under water stress conditions, besides the plants treated with HA + PEG presented higher fresh biomass than those treated with PEG alone. Soluble metabolite contents and dry mass of different plant organs show that HA contributed to the osmotic balance of plants subjected to stress.
MEMBROS DA BANCA:
Externo à Instituição - EDNALDO DA SILVA ARAÚJO - EMBRAPA
Interno - 2626406 - LEANDRO AZEVEDO SANTOS
Presidente - 387406 - RICARDO LUIZ LOURO BERBARA