The Occurrence of Nitro-Toxins in North American Astragalus (Fabaceae)

Williams, M. C.; Barneby, Rupert C.

doi:10.2307/2806203

Cited by 75 publications

(34 citation statements)

References 14 publications

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“…The first of these explanations seems unlikely, given that neither of the most common organic defenses found in Astragalus (aliphatic nitro and indolizidine alkaloids (Rios and Waterman 1997)) have been found in A. bisulcatus (Williams and Barneby 1977). Although 263 (52 %) of the North American Astragalus species tested contained detectable amounts of these compounds, only 1 of the 24 hyperaccumulator species tested contained them.…”

Section: Herbivory and Elemental Defensementioning

confidence: 85%

Characterization and benefits of selenium uptake by an Astragalus hyperaccumulator and a non-accumulator

2016

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Background and Aims We characterized the relationship between soil and leaf concentrations of selenium in a hyperaccumulator and a non-accumulator to test the hypothesis that hyperaccumulators take up selenium while non-accumulators exclude it. We examined plant performance metrics and the ability of selenium to protect against herbivory by spider mites. Methods Known hyperaccumulator and non-accumulator species within the genus Astragalus were grown under a range of selenium concentrations and measured for tissue selenium, extent of herbivory, and vigor. Results Both hyperaccumulators and non-accumulators either failed to meet even the lenient threshold or exceeded even the strict threshold for hyperaccumulation depending on soil concentration. Both had decreased herbivory with increasing leaf selenium, and both grew larger at higher levels of selenium regardless of herbivory, despite a negative impact of higher relative uptake. Conclusions The relationships between selenium dosage and tissue concentrations matched only some model predictions. Under these conditions, the bioconcentration factor was a better delimiter between species than the absolute tissue concentration. We provide evidence that despite the apparent cost of uptake, selenium can enhance the growth of hyperaccumulators even when herbivory is not a significant factor. We propose the term Belemental stimulation^for this phenomenon.

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Section: Herbivory and Elemental Defensementioning

confidence: 85%

Characterization and benefits of selenium uptake by an Astragalus hyperaccumulator and a non-accumulator

2016

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“…However, whereas A . falcatus contained extremely high levels of nitro-toxins (Williams and Barneby, 1977), none were found in 0. riparia (Williams and Molyneux, 1988). Preliminary examination of other non-native Astragalus and Oxytropis has indicated that swainsonine production is not confined to North American species.…”

Section: Analysis Of Swainsonine In Plant Samplesmentioning

confidence: 93%

“…This is in accord with field observations that livestock may be poisoned by consumption of senescent locoweeds (Panter et al, 1988). The apparent stability of the alkaloid in dry plant material suggests that analysis of herbarium specimens, particularly seeds, could be used to study the distribution of swainsonine within the taxonomic sections of Astragalus, as has been done for the nitro-toxins (Williams and Barneby, 1977). Whether or not consistent patterns of occurrence may be found is not apparent from the limited number of samples so far investigated.…”

Section: Analysis Of Swainsonine In Plant Samplesmentioning

confidence: 99%

Analysis and distribution of swainsonine and related polyhydroxyindolizidine alkaloids by thin layer chromatography

Molyneux

James

Panter

et al. 1991

Phytochemical Analysis

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A spray reagent which is sensitive and specific for polyhydroxyindolizidine glycosidase inhibitors such as swainsonine and castanospermine has been developed for their visualization on thin layer chromatographic plates. The method involves treatment of the plates with a sequential system consisting of 10% acetic anhydride in benzene, followed by Ehrlich's reagent. This technique has been used to follow the isolation and purification of minor alkaloidal constituents from Astragalus lentiginosus and Castanospermum australe. The occurrence of swainsonine and its N‐oxide in a number of Astragalus and Oxytropis species has been investigated. Species previously incriminated as locoweeds on the basis of field observations were all shown to contain the alkaloid and it was also found to occur in additional species. The highest levels of swainsonine were found in the seeds and pods, with lesser amounts in the leaves and stems, and none detectable in the roots.

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“…Although a few aromatic compounds bearing one nitro group as a substituent are produced as secondary metabolites by microorganisms (31,44,45,49) the majority of nitroaromatic compounds in the environment are due to anthropogenic activities, Nitrations are important reactions for the large-scale production of aminoaromatic structures that are synthons for pesticides, dyes, polymers, and pharmaceuticals. Nitroaromatic compounds such as nitrobenzene are used as solvents, whereas polynitroaromatic compounds serve as explosives.…”

mentioning

confidence: 99%

Basic Knowledge and Perspectives on Biodegradation of 2,4,6-Trinitrotoluene and Related Nitroaromatic Compounds in Contaminated Soil

Rieger

Knackmuss

1995

Biodegradation of Nitroaromatic Compounds

208

193

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The Occurrence of Nitro-Toxins in North American Astragalus (Fabaceae)

Cited by 75 publications

References 14 publications

Characterization and benefits of selenium uptake by an Astragalus hyperaccumulator and a non-accumulator

Characterization and benefits of selenium uptake by an Astragalus hyperaccumulator and a non-accumulator

Analysis and distribution of swainsonine and related polyhydroxyindolizidine alkaloids by thin layer chromatography

Basic Knowledge and Perspectives on Biodegradation of 2,4,6-Trinitrotoluene and Related Nitroaromatic Compounds in Contaminated Soil

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