Banca de DEFESA: TADEU AUGUSTO VAN TOL DE CASTRO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : TADEU AUGUSTO VAN TOL DE CASTRO
DATE: 10/11/2023
TIME: 13:00
LOCAL: sala 24 do departamento de solos
TITLE:

Potentialities of humic substances, algae extracts and their combinations as biostimulants in plants: structural characteristics and mode of action.

KEY WORDS:

Humic acid, fulvic acid, Kappaphycus alvarezii, characterization, bioactivity.

PAGES: 215
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:

The growing global demand for food has led to more intensive land use. In this context, new and advanced bioinputs have emerged, such as biostimulants and biofertilizers, with the aim of promoting a harmonious integration between food production and sustainable soil management. The interest in using biostimulants based on humic substances (HS) in cultivated areas is already a reality among farmers. On the other hand, the sea economy has been increasingly inserted into the agrarian production chain with the aim of generating cleaner and more efficient agricultural products. Given this reality, this thesis aimed to evaluate the biostimulant effects on cucumber plants (Cucumis sativus) of the Ashley variety and rice (Oryza sativa L.) of the nippombare variety, of humic fractions extracted from vermicompost and leonardite, of algae extracts extracted from kappaphycus alvarezii, as well as their combinations, applied via foliar and/or root, previously characterized. In chapter I, the physicochemical characterization of vermicompost humic acid (HAVC), vermicompost fulvic acid (FAVC) and leonardite humic acid (HACHECO) was presented and the bioactivity and mode of action of these SH in plants were discussed. In chapter 2, the physical-chemical characterization of subfractions of the algae Kappaphycus alvarezii (aqueous extract and solid biomass) in natura (without addition of preservatives) was presented and the effect of application modes (foliar and root) on growth and development was evaluated, in addition of the different resulting modes of action. In chapter 3, the stimuli triggered by the isolated and joint foliar application of FAVC and Kappaphicus alvarezii extract in plants were evaluated and compared, on gene regulation, metabolism, absorption and assimilation of nutrients, photosynthetic performance, root development and growth, aiming to obtaining a mixed foliar biostimulant with agricultural potential. The physicochemical characteristics of humic substances and Kappaphicus alvarezii extracts resulted in different properties and bioactivity exerted on plants, with differences in gene expression, hormonal regulation, photosynthesis, nutrient absorption, amounts of soluble metabolites, root architecture and accumulation of biomass. In general, the application of all natural compounds resulted in plants with greater development, but with different forms depending on their structural characteristics. The root and foliar application of FAVC and K-sap resulted in different stimuli on root growth and biomass production, with the best response doses being different for each compound and form of application. For both FAVC and K-sap, applications at lower concentrations were necessary in the roots than in the leaves to stimulate a greater response. The costs associated with the production and commercialization of these foliar biostimulants are considered low, since they are extracted from natural compounds and sprayed in small doses, in addition to the potential to be used in the conservation and management of natural and agricultural ecosystems, as they are biodegradable and not -toxic. The mixed foliar biostimulant with AFVC at 80 mg L^-1 + K-sap at 2% showed potential to be used commercially in the cultivation of rice plants, increasing their production

COMMITTEE MEMBERS:
Presidente - 1399485 - ANDRES CALDERIN GARCIA
Externa à Instituição - DARIELLYS MARTÍNEZ BALMORI
Interno - 2213075 - EVERALDO ZONTA
Externo ao Programa - 2630672 - FLAVIO COUTO CORDEIRO - nullExterno à Instituição - MARCIO OSVALDO LIMA MAGALHÃES - UNEMAT