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Romeo, John T.

doi:10.1023/a:1005599828335

Cited by 47 publications

(6 citation statements)

References 6 publications

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“…However, the mere presence of allelochemicals in the donor plant and their antimicrobial activities in artificial medium (e.g. agar) do not demonstrate an allelopathic activity in natural conditions (Romeo 2000), because soil microorganisms consume a high quantity of organic molecules and, thus, inhibitory compounds may not accumulate at toxic levels. The microbial degradation of allelochemicals depends on the chemical nature of the considered compound, on soil texture, structure, aeration, temperature, SOM and pH, as well as on the microbial species involved.…”

Section: Interaction Between Allelochemicals and Soil Microorganismsmentioning

confidence: 99%

Plant allelochemicals: agronomic, nutritional and ecological relevance in the soil system

2019

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Background Allelopathy is an ecological phenomenon consisting of both positive and negative effects between organisms determined by the release of secondary metabolites into the environment. Root exudation represents the most important pathway of releasing allelochemicals. Once released into the soil, allelochemicals interact with the organic and inorganic soil phases, as well as with soil microorganisms. The set of these interactions fix allelochemicals bioavailability and phytotoxic level. Scope Here we critically review the interactions between plant allelochemicals and physical, chemical and biological soil characteristics by reporting the literature available and pointing out both positive and negative relationships affecting allelochemicals phytotoxicity and nutrient availability. In addition, we have reported a qualitative balance of allelochemicals in the soil. Thirdly, we reviewed the exudation process of allelochemicals and the transport mechanisms across plasma membranes. Conclusions A two-way relationship exists between soil characteristics and allelochemicals. The level of phytotoxicity is not affected only by a single soil characteristic, but they are closely linked to each other and exert a multiple-effect on retention, transport and transformation processes of allelochemicals in soil. Further efforts are needed to better understand the interactions involved in soil allelopathy and to create new opportunities for a sustainable control of agroecosystems.

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Section: Interaction Between Allelochemicals and Soil Microorganismsmentioning

confidence: 99%

Plant allelochemicals: agronomic, nutritional and ecological relevance in the soil system

2019

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“…In fact, allelopathy has recently been proposed as a novel mechanism for the spread and establishment of invasive species in the alien environments (Bais et al 2004). Romeo (2000) opined that allelopathic nature of a plant could be established only when laboratory bioassays are conducted under ecologically realistic conditions. Blum et al (1999) suggested the use of soil as a plant growth medium for demonstrating allelopathic nature of a plant.…”

Section: Introductionmentioning

confidence: 99%

Nature of interference potential of leaf debris of Ageratum conyzoides

et al. 2008

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The present study investigated the allelopathic interference of leaf debris of Ageratum conyzoides (billy goat weed; Asteraceae)-a weed of cultivated land-against rice (Oryza sativa). Seedling length and dry weight of rice were significantly reduced (16-20%) in soil from A. conyzoides infested fields compared to the soil from an area devoid of the weed. It indicated the presence of certain phytotoxins in the A. conyzoides infested soil. To explore the possible contribution of the weed in releasing these phytotoxins, growth studies involving leaf debris extracts and amended soils (prepared by incorporating leaf debris-5, 10, 20 g kg -1 soil, w/w, or its extracts-0.5%, 1.0% and 2.0%, v/v) were conducted. The growth of rice was severely inhibited in A. conyzoides leaf debris-and debris extractamended soils compared to unamended control soil. A significant amount of water-soluble phenolics, the potent phytotoxins, was found in the A. conyzoides infested soil, leaf debris, and debris-amended soils. These phenolics were identified as gallic acid, coumalic acid, protocatechuic acid, catechin and p-hydroxybenzoic acid. Among these, protocatechuic acid was in the maximum amount (35.72%) followed by coumalic acid (33.49%) and these two accounted for[69% of total phenolic compounds. Further, there was a significant increase in the available nutrient content in soil amended with A. conyzoides leaf debris thus ruling out the possibility of any resource depletion upon residue incorporation and their negative role in causing growth reduction. Based on the observations, the present study concludes that leaf debris of A. conyzoides deleteriously affects the early growth of rice by releasing water-soluble phenolic acids into the soil environment and not through soil nutrient depletion.

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“…Allelopathic interactions are challenging to characterize in general, in that a large number of potential interacting allelochemicals with species-specific effects can be involved (Zhang et al 2021). Indirect effects such as those mediated by soil microflora and mycorrhizae may be common (Stinson et al 2006), including either microbial degradation of allelochemicals and "indirect allelopathy" where microbial metabolic products show increased allelopathic effects (Romeo 2000;Scavo et al 2019).…”

Section: Discussionmentioning

confidence: 99%

Biochar mitigation of allelopathic effects in three invasive plants: evidence from seed germination trials

et al. 2022

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Many invasive species show allelopathic effects that contribute to competitive impacts on native vegetation for which few control measures exist. We investigated the potential for pyrolized organic material used as a soil amendment (“biochar”) to sorb allelochemicals and mitigate allelopathic effects on seed germination and early seedling development in three common invasive plants in Canada, garlic mustard (Alliaria petiolata), tree of heaven (Ailanthus altissima) and yellow sweetgrass (Melilotus officinalis). We hypothesized that biochars would mitigate effects on germination and early seedling development (radicle extension and cotyledon development) through sorption of allelochemicals. Laboratory assays of seed germination and early seedling development of two agricultural crops (Lactuca sativa and Raphinus raphanistrum) and two native grass species (Andropogon gerardi and Poa palustris) were conducted using water extracts from leaves. Seeds were treated with plant extracts exposed to four different biochars (red oak (Quercus rubra), jack pine (Pinus banksiana), shipping pallet and construction waste, and, high-carbon wood ash) using a range of extract and biochar dosages. Treatment of allelopathic plant extracts by biochars significantly (p <0.05) mitigated effects on seed germination for Alliaria and Melilotus. Effects on seed germination and early seedling development depended on extract concentration, biochar dosage, and the target species assessed. Controls treated with biochar leachate alone showed significantly (p <0.05) increased germination for two of the biochars tested (jack pine biochar and high-carbon wood ash). Results indicated that biochars can mitigate allelopathic effects of invasive species through sorption of allelochemicals, however this will be effective in only some cases.

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Cited by 47 publications

References 6 publications

Plant allelochemicals: agronomic, nutritional and ecological relevance in the soil system

Plant allelochemicals: agronomic, nutritional and ecological relevance in the soil system

Nature of interference potential of leaf debris of Ageratum conyzoides

Biochar mitigation of allelopathic effects in three invasive plants: evidence from seed germination trials

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