Root Exudation of Herbicides by Woody Plants: Allelopathic Implications

Reid, C. P. P.; Hurtt, Woodland

doi:10.1038/225291a0

Cited by 17 publications

(16 citation statements)

References 9 publications

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“…Fifty µl of saline or drug solution was given through the right side of the dorsal cephalothoraxic-abdominal membrane, by means of a syringe fitted with a sleeve to control the depth of penetration to 4 mm, thus ensuring that the injected solution was released in the pericardial sac. The lack of an endothelial blood-brain barrier in crabs [28], together with the fact that blood is distributed throughout an extensive capillary system [29] makes it possible for the injected drugs to reach the various neuropil areas of the brain. Drug solutions ranged from 1 to 4 mM for OA (corresponding to 0.56 to 2.24 µg/g), 1 to 6 mM for epinastine (0.84 to 5 µg/g) and 1 to 5 mM for mianserin (0.88 to 4.4 µg/g).…”

Section: Methodsmentioning

confidence: 99%

Contrasting Role of Octopamine in Appetitive and Aversive Learning in the Crab Chasmagnathus

Kaczer

Maldonado

2009

PLoS ONE

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BackgroundBiogenic amines are implicated in reinforcing associative learning. Octopamine (OA) is considered the invertebrate counterpart of noradrenaline and several studies in insects converge on the idea that OA mediates the reward in appetitive conditioning. However, it is possible to assume that OA could have a different role in an aversive conditioning.Methodology/Principal FindingsHere we pharmacologically studied the participation of OA in two learning processes in the crab Chasmagnathus granulatus, one appetitive and one aversive. It is shown that the aversive memory is impaired by an OA injection applied immediately or 30 minutes after the last training trial. By contrast, the appetitive memory is blocked by OA antagonists epinastine and mianserine, but enhanced by OA when injected together with the supply of a minimum amount of reinforcement. Finally, double-learning experiments in which crabs are given the aversive and the appetitive learning either successively or simultaneously allow us to study the interaction between both types of learning and analyze the presumed action of OA. We found that the appetitive training offered immediately, but not one hour, after an aversive training has an amnesic effect on the aversive memory, mimicking the effect and the kinetic of an OA injection.Conclusions/SignificanceOur results demonstrate that the role of OA is divergent in two memory processes of opposite signs: on the one hand it would mediate the reinforcement in appetitive learning, and on the other hand it has a deleterious effect over aversive memory consolidation.

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Section: Methodsmentioning

confidence: 99%

Contrasting Role of Octopamine in Appetitive and Aversive Learning in the Crab Chasmagnathus

Kaczer

Maldonado

2009

PLoS ONE

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“…, 1996). In particular, Reid and Hurtt (1970) verified root exudation of picloram and 2,4,5‐trichlorophenoxyacetic acid when they were applied in sub‐lethal doses on the leaves of two tree species, red maple ( Acer rubrum L.) and green ash ( Fraxinus pennsylvanica Marsh.). Coupland and Caseley (1979) observed that couch grass ( Elytrigia repens (L.) Desv.…”

Section: Introductionmentioning

confidence: 85%

“…In particular, there are reports indicating that certain herbicides, when applied as foliar treatments, can translocate through plant vascular systems and exude unchanged from roots (Linder et al. , 1964; Reid & Hurtt, 1970; Coupland & Caseley, 1979; Rodrigues et al. , 1982; Awad et al.…”

Section: Introductionmentioning

confidence: 99%

Root exudation of diclofop‐methyl and triasulfuron from foliar‐treated durum wheat and ryegrass

et al. 2007

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In this study, we evaluated the release of diclofopmethyl and triasulfuron from the roots of foliar-treated ryegrass and wheat. The study with 14 C-diclofop-methyl indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass. No root exudation from 14 C-diclofop-methyl-treated wheat plants was observed, while 20 days after treatment (DAT) 0.2-0.9% of radioactivity absorbed by ryegrass was found exuded in the growing medium. Root exudation was stimulated three to six times by the presence of untreated wheat or ryegrass sharing the growing medium with diclofop-methyl-treated ryegrass. No subsequent uptake of exuded radiolabel by untreated plants (ryegrass or wheat) in the same pot with 14 C-diclofop-methyl-treated ryegrass was observed. The study with 14 C-triasulfuron indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass and also into the growing medium. By 20 DAT, 0.5-4.2% of radioactivity absorbed by wheat or ryegrass was found exuded in the growing medium. The presence of untreated plants (wheat or ryegrass) in the same pot as triasulfurontreated ryegrass or wheat induced exudation seven to 32 times more. The study also revealed a subsequent uptake of exuded compounds by untreated wheat or ryegrass sharing the medium of 14 C-triasulfuron-treated plants. This study has demonstrated for the first time that the root exudation of exogenous compounds can be related to plant arrangement in pots. The implication is that herbicide root exudation and transfer, a form of allelopathy, could be significant in the field. A precise estimation of environmental fate, unexpected ecological side effects and residual activity of herbicides may require quantification of such exudation.

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“…There are two likely explanations, the first concerns the possible preferential leakage of picloram from root nodules into the solution bathing the roots. The leakage of picloram from root systems to soil has been demonstrated in red maple {Acer rubrum L.) (Reid & Hurtt, 1970) and Canada thistle {Cirsium arvense L.) (Sharma et al, 1971). It is possible that leakage of picloram from root systems of gorse, to nutrient solution was greater than into soil and may occur prefer-entially from the root nodules.…”

Section: Discussionmentioning

confidence: 99%

The preferential accumulation of picloram at sites of active growth in gorse (Ulex europaeus L.)

Field

Hai

1980

Weed Research

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Summary: Application of 14C‐picloram to single spines of 6 month old, soil grown, vegetative plants of gorse (Ulex europaeus L.) resulted in its translocation to regions of meristematic and metabolic activity, with significant accumulation in the stem apex and root nodules. Dissection of the root system of plants grown in nutrient solution revealed a greater mass of picloram in differentiated root tissue than in root apices, although the concentration of chemical in the latter fraction was greater than in the former. Loss of picloram to the nutrient solution was interpreted as preferential leakage from the root nodules because of the lack of picloram accumulation in this fraction. In reproductive plants bearing flowers and floral buds the picloram was diverted from the root tissue fractions to the floral organs, which constituted the primary sink.

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Root Exudation of Herbicides by Woody Plants: Allelopathic Implications

Cited by 17 publications

References 9 publications

Contrasting Role of Octopamine in Appetitive and Aversive Learning in the Crab Chasmagnathus

Contrasting Role of Octopamine in Appetitive and Aversive Learning in the Crab Chasmagnathus

Root exudation of diclofop‐methyl and triasulfuron from foliar‐treated durum wheat and ryegrass

The preferential accumulation of picloram at sites of active growth in gorse (Ulex europaeus L.)

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