African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6842

Full Length Research Paper

Allelopathic effects of aqueous extract of leaves and roots of Luetzelburgia auriculata (Allemão) Ducke on seeds germination and initial growth of lettuce (Lactuca sativa L.)

PINTO Erika do Nascimento Fernandes
  • PINTO Erika do Nascimento Fernandes
  • Faculdade de Ciências Florestais, Departamento de Engenharia cientÍfica da Universidade Federal de Campina Grande, Brazil.
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SOUTO Jacob Silva
  • SOUTO Jacob Silva
  • Faculdade de Ciências Florestais, Departamento de Engenharia cientÍfica da Universidade Federal de Campina Grande, Brazil.
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PEREIRA Leonardo Francisco de Assis
  • PEREIRA Leonardo Francisco de Assis
  • Faculdade de Ciências Florestais, Departamento de Engenharia cientÍfica da Universidade Federal de Campina Grande, Brazil.
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BORGES Cesar Henrique Alves1
  • BORGES Cesar Henrique Alves1
  • Faculdade de Ciências Florestais, Departamento de Engenharia cientÍfica da Universidade Federal de Campina Grande, Brazil.
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FERNANDES Tassia Rayane Nascimento
  • FERNANDES Tassia Rayane Nascimento
  • Federal University of Rio Grande do Norte Technology Center, Brazil.
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  •  Received: 25 June 2016
  •  Accepted: 11 November 2016
  •  Published: 29 March 2018

Abstract

The secondary metabolism of plants produces allelopathic substances which are able to interfere with germination and growth of other species, when released in the environment. In order to evaluate the allelopathic effects of Luetzelburgia auriculata on the germination and early growth of lettuce (Lactuca sativa), leaf extracts and roots were tested in lettuce seeds sowing. The L. auriculata plant material was collected from adults, subsequently washed, dried, weighed, crushed and thus used to preparing a raw extract. In a completely randomized design, six concentrations (0, 20, 40, 60, 80 and 100%) of the extracts of leaves and roots were tested separately with four replications on lettuce seeds in germitest paper. The experiment was conducted in a germination chamber TE 402 during seven days with photoperiod of 12 h light and a constant temperature of 20°C, to check the germination speed index (GSI), germination percentage (% G) and initial growth lettuce (radicle length and hypocotyl). The data were submitted to a variance analysis applying the F test at 1% probability and using the error bars model. It was observed that the results of the treatments with root extract and leaf extract, when compared to the control test, were negatively affected by the aqueous extracts of L. auriculata. The GSI and %G of seeds treated with roots extract were the parameters that presented most significant responses to the allelopathic effects of L. auriculata extract at 20% concentration, followed by GSI and %G seeds subjected to 20% leaf extract. Both extracts at other concentrations reduced GSI and %G in 85 and 90%, respectively. The length of the radicle and hypocotyl decreased by 32 and 15% respectively when the extract was used at a lower concentration, and 40% (radicle) and 30% (hypocotyl) in other concentrations. The aqueous extracts of leaves and roots L. auriculata caused negative allelopathic interference on the germination and growth of lettuce seedlings.

Key words: Secondary metabolites, Brazilian semiarid region, allelopathy.