Name: LÍVIA DORSCH ROCHA
Type: PhD thesis
Publication date: 16/03/2018
Advisor:
Name |
Role |
|---|---|
| Silvia Tamie Matsumoto | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Antelmo Ralph Falqueto | Internal Examiner * |
| Camilla Rozindo Dias Milanez | Internal Examiner * |
| Dânia Elisa Christofoletti Mazzeo | External Examiner * |
| Iara da Costa Souza | External Alternate * |
| Leonardo Barros Dobbs | External Examiner * |
| Paulo Cezar Cavatte | Internal Alternate * |
| Silvia Tamie Matsumoto | Advisor * |
Summary: ABSTRACT
The lack of disposal of solid waste generated by sewage sludge treatment has motivated research in the area of cycling of these materials. One of the alternatives that has been investigated is an extraction of chemical substances and / or their bioactive fractions. Humic acid is one of the fractions most investigated due to its high interactivity with the vegetable promoting its growth through the biochemical development. It is also known that abiotic stress caused by water deficiency compromises the physiological plant development as well as its growth. (AH-LE- 2.0 mM C L-1) in maize seedlings stressed by NaCl-100 mM (saline stress) and by PEG 6000 (water restriction) by integrating elemental, physiological, biochemical, toxicogenic and of plant growth, seeking to evaluate the potential benefits / risks of using this biostimulant. A solution for the application of humic acid from sewage sludge was performed with hydroponics in maize seedlings with water restriction (PEG 6000 + NaCl) with application of acid (2.0 mM C L-1). Results of the quantification of the elements C, H, N o O AH-LE indicated it as a source of nutrients for the plants due to the availability of these elements. Photosynthesis rates, such as carbon assimilation, transpiration and conductance, are shown to be attenuated in treatments with the addition of humic acid, both in saline stress and in water deficit. Growth rates corroborated with photosynthesis results indicating lower biomass loss of plant organs and higher root growth when related to treatments with humic acid under stress. In addition, biochemical antioxidant markers (SOD, APX) ratified the biochemical potential of AH-LE in increasing the defense of plants under water deficiency against reactive oxygen species. It was also observed higher activity of enzymes bound to plasma membrane permeability such as H + -ATPases in treatments with humic material confirming this intrinsic characteristic. Another biochemical indicator of abiotic stress was the accumulation of the amino acid proline that was shown to be more efficient in stress plants with AH-LE addition. These plants are successful in LPP and electrolyte leakage and are less affected by their effects. In addition, a toxicogenic analysis did not indicate cytotoxic, genotoxic and mutagenic potentials in the treatments, thus evidencing greater safety with the use of AH-LE alection cell. Considering these results, it is possible to suggest a use of humic acid in plants stressed by water restriction as a remedy of the effects caused by water deficiency.
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Keywords: humic material sanitary effluent plant physiology abiotic stress corn
