Name: Maria Gabriela Marques de Souza
Type: MSc dissertation
Publication date: 05/03/2020
Advisor:
Name |
Role |
|---|---|
| Hildegardo Seibert França | Advisor * |
| Viviana Borges Corte | Co-advisor * |
Examining board:
| Name |
Role |
|---|---|
| Elias Terra Werner | Internal Alternate * |
| Hildegardo Seibert França | Advisor * |
| Janaína Brandão Seibert | External Examiner * |
| MARCOS THIAGO GAUDIO GOMES | External Alternate * |
| Maria do Carmo Pimentel Batitucci | Internal Examiner * |
| Viviana Borges Corte | Co advisor * |
Summary: The genus Eucalyptus has a high economic interest, due to its versatility regarding its use and the potential of its wood. Allelopathy exerted on other plants is one of the effects associated with eucalyptus monoculture. The hybrid Eucalyptus urograndis (E. urophylla x E. grandis) is used in Brazil for its desirable characteristics such as wood quality and resistance to drought and to the fungus Cryphonectria cubensis. Despite its high economic importance, studies addressing the hybrid in question, addressing its allelopathic activity, are scarce. The objective of this work is to evaluate the allelopathic potential of ethanolic extracts and their fractions, harvest mature leaves and litter of Eucalyptus urograndis, on the germination and initial growth of Lactuca sativa L. and Cedrela fissilis Vell.. The plant material was submitted to extraction with ethanol until depleted. The crude extract obtained was fractionated to hexane (HEX), dichloromethane (DCM), ethyl acetate (ACE), butanol (BUT) and aqueous (AQ) as fractions. To test the allelopathic potential of extracts and fractions, a bio-germination test with a test of 0; 1.25; 2.5; 5 and 10mg / L, using L. sativa and C. fissilis as seeds. The experiment was conducted for 7 and 21 days, respectively, evaluated daily for germination. The parameters analyzed were germination percentage (% G), germination speed index (IVG) and initial growth, length, fresh and dry mass of shoot and root. Alkaloids, anthracene derivatives, coumarins, lignans, mono, diterpenes, triterpenes, sesquiterpenes, steroids and phenols were detected. Only the crude extracts, such as the HEX and DCM fractions negatively affected the germination percentage, as the other fractions have greater influence on the initial growth, proportional to the concentration tested. However, as DCM fractions affected all variables analyzed more pronouncedly, even at the lowest concentration tested. L. sativa was more sensitive to extracts and fractions than C.fissilis. In the activity of DCM fractions, you should have a presence of allelopathic potential essential components already known and given their negative effect on the germination and initial growth of the potential bioherbicidal fraction. Based on the selected data, the hybrid has allelopathic potential, can inhibit the germination or growth of other plant species, however, its action depends on the concentration of secondary compounds.
Keywords: Allelochemicals fractionation leaf extracts phytotoxicity rose cedar
