Allelopathic potential of orsellinic acid derivatives

Abstract

ABSTRACT

Lichen-plant interactions

“…This information may further support the recent suggestion of using lichen compounds, which are chemically simple and are possibly easily synthesized in the laboratory, as herbicides (Dayan and Romagni 2001;Duke et al 2002). However, the different effects, ranging from inhibition to stimulation, that have been observed on different tested plants (Peres et al 2009) will also have to be taken into account.…”

“…Water extracts of terricolous lichens, including several Cladonia species and the foliose Peltigera canina, have been shown, in vitro, to reduce the seed germination of several vascular plants, including Gymnosperms (e.g., Pinus sylvestris) and Angiosperms, trees, shrubs, forbs and grasses (Pyatt 1967;Lawrey 1984;Hobbs 1985;Sedia and Ehrenfeld 2003). Growth parameters, e.g., root elongation, are even more sensitive to allelopathic effects than seed germination (Peres et al 2009): in multi-assay laboratory experiments, the growth of forbs and grasses has been inhibited by most of the tested, purified lichen metabolites at concentrations ranging from 10 (3 to 10 (9 M, while stimulation effects have been reported for a few compounds at lower concentrations (Lawrey 1984 and references therein;Nishitoba et al 1987;Cardarelli et al 1997;Rojas et al 2000;Peres et al 2009). Some authors have suggested that the chemical structure, e.g., the number and length of alkyl groups bonded to the benzene rings and to phenolic oxygen, is important in terms of activity (Nishitoba et al 1987;Peres et al 2009).…”

“…Growth parameters, e.g., root elongation, are even more sensitive to allelopathic effects than seed germination (Peres et al 2009): in multi-assay laboratory experiments, the growth of forbs and grasses has been inhibited by most of the tested, purified lichen metabolites at concentrations ranging from 10 (3 to 10 (9 M, while stimulation effects have been reported for a few compounds at lower concentrations (Lawrey 1984 and references therein;Nishitoba et al 1987;Cardarelli et al 1997;Rojas et al 2000;Peres et al 2009). Some authors have suggested that the chemical structure, e.g., the number and length of alkyl groups bonded to the benzene rings and to phenolic oxygen, is important in terms of activity (Nishitoba et al 1987;Peres et al 2009). However, other evidence, e.g., the inhibitory effect of methylorsellinate, which has only one methyl substitution, on the radicle growth of Amaranthus hypochondriacus (Amaranthaceae) and Echinochloa crusgalli (Poaceae) (Rojas et al 2000), would seem to suggest that a direct correlation between toxicity and chemical structure, as previously discussed for bryophytes, cannot be claimed (Lawrey 1986).…”

“…However, other evidence, e.g., the inhibitory effect of methylorsellinate, which has only one methyl substitution, on the radicle growth of Amaranthus hypochondriacus (Amaranthaceae) and Echinochloa crusgalli (Poaceae) (Rojas et al 2000), would seem to suggest that a direct correlation between toxicity and chemical structure, as previously discussed for bryophytes, cannot be claimed (Lawrey 1986). The different effects of lecanoric acid (extracted from the foliose Parmotrema tinctorum) and its orsellinate derivatives on the germination and growth of Lactuca sativa (poorly affected) and Allium cepa (strongly affected) have highlighted that the allelopathic action of certain metabolites can vary to a great extent between different plant species (Peres et al 2009). …”

Padronização de bioensaios para detecção de compostos alelopáticos e toxicantes ambientais utilizando alface

“…Segundo as RAS (BRASIL, 2009), a exposição das cipselas de alface a um período de 8 a 16 horas de luz por dia pode ser benéfica e é recomendada a fim de fornecer condições mais propícias para o crescimento das estruturas essenciais das plântulas, facilitando a avaliação e diminuindo as possibilidades de ataque por microrganismos. Entretanto, na literatura são encontrados também trabalhos que fazem o uso de luz constante (PERES et al, 2004;PERES et al, 2009;WANDSCHEER et al, 2011).…”