Assessment method for allelopathic effect from leaf litter leachates

Abstract

In order to elucidate the allelopathic effect of leaf litter leachates under laboratory conditions, a modified 'sandwich method', which places leaves between two layers of agar, was used. Fifty mg of leaves was used per 10 cm 2 cell. Agar concentrations at 0.5-1.0% were the best for gel support in determining radicle and hypocotyl elongation of lettuce. The optimum incubation time for bioassay was three days after imbibition onset. Among 20 typical tree species in Asia, Cymbopogon citratus and Derris scandens showed the strongest inhibitory activity determined by the sandwich method, followed by Piper betle, Tamarindus indica, and Gliricidia sepium. This bioassay seems to be a reliable method for screening allelopathic activity from leaf litter leachates.Keywords: allelopathy, leaf litter leachate, sandwich method.identify allelochemiclas in situ. However, the elucidation of allelochemicals and their involvement in the allelopathy phenomenon are difficult because of the lack of route-specific bioassay methodologies. From this viewpoint, we were developing several bioassay and assessment methods in order to explore route-specific identification of allelochemicals under laboratory conditions. Previously we reported on the assessment procedure referred to as the 'plant-box method' to evaluate allelopathy through root exudates (Fujii 1992). In this article, the laboratory-based assessment method for allelopathy through fallen leaves from trees, crops and weeds is reported. Leaf litter leachates play an important role in natural conditions, and in practical farming systems such as mulching by leaf litter. Mulching with straw is a common traditional farming system in the Japanese 'Shiki-wara'. The aim of this work was to evaluate the allelopathic activity from leaf litter leachates, which was placed between two layers of agar, using the sandwich method. MATERIALS AND METHODS Selection of gel-supportTo select a suitable gelling material, we tested several compounds such as agar, kaolinite, silica gel, gelatin and

Exploring Alternative Use of Medicinal Plants for Sustainable Weed Management

“…The Standard Deviation Variance (SDV) concept was adopted to categorise the allelopathic activity [61,66]. For the statistical analysis, the mean and standard deviation were calculated and the criterion of the SDV was evaluated.…”

Establishment of a homogenized method for environmental biosafety assessments of transgenic plants

“…Allelopathic activity was evaluated according to the previously described sandwich method (Fujii et al 2003(Fujii et al , 2004. A dried leaf was placed in each well of a 6-well multi-dish plastic plate (f35 mm), and 5 mL of a low-melting agar (0.5% w/v) solution was poured on top.…”

“…The sandwich method, which is among the most used, assays the allelopathic activity of leachates from dried leaves on seed germination and growth receptor plants such as lettuce (Fujii et al 2003(Fujii et al , 2004. This method has been used to compare the allelopathic activity of non- …”

Controle de plantas daninhas na cultura do milho com gliricídia em consorciação

“…Esses compostos podem atuar tanto como aleloquímicos quanto como sinais de detecção de plantas vizinhas (Kegge & Pierik, 2009 Controle de plantas daninhas na cultura do milho com gliricídia ... constatação indica que a gliricídia beneficiou o milho, embora não tenha influenciado, como mencionado, a densidade e a biomassa da parte aérea das plantas daninhas. Apesar disso, vários autores (Fujii et al, 2004;Oyun, 2006) identificaram ação alelopática da parte aérea da gliricídia, não avaliada no presente trabalho. Embora as substâncias alelopáticas da gliricídia possam ter alguma influência sobre o milho, isso não foi verificado quando ramos de gliricídia foram utilizados no controle das plantas daninhas dessa gramínea (Kamara et al, 2000).…”